JP2013113943A - Polarizing plate protective film, polarizing plate, and liquid crystal display device - Google Patents

Abstract

An object of the present invention is to provide a polarizing plate protective film that maintains sufficient adhesion even when irradiated with light for a long period of time and has excellent scratch resistance.
A cellulose acylate film containing a hindered amine compound,
An active energy ray-curable resin layer;
Between the cellulose acylate film and the active energy ray curable resin layer, a mixed layer containing cellulose acylate and an active energy ray curable resin,
A polarizing plate protective film having a thickness ratio of 0.05 to 0.80 in the mixed layer represented by the following general formula (1).
General formula (1)
(Mixed layer thickness ratio) = (Mixed layer thickness) / [(Mixed layer thickness) + (Active energy ray cured resin layer thickness)]
[Selection figure] None

Description

  The present invention relates to 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 improving the scratch resistance, an active energy ray-curable resin layer that is cured by irradiation with an active energy ray is applied on a protective film of a polarizing plate to increase a layer having high hardness (hereinafter referred to as a hard coat layer). The method is common. It is also known that increasing the surface hardness of the polarizing plate protective film itself is effective, and Patent Document 1 discloses a method of using a cellulose acylate film having a high surface hardness as a polarizing plate protective film. Yes.

  As a polarizing plate in a liquid crystal display device, a configuration in which a polarizer using polyvinyl alcohol (PVA) and iodine is sandwiched between polarizing plate protective films such as a cellulose acylate film is widely used. However, a polarizer using PVA and iodine has a weak point that the polarizer performance is likely to deteriorate under a high temperature and high humidity environment, and improvement is required to meet the required performance for outdoor use.

  In outdoor applications, even more severe durability is required for the functional layer than in indoor applications. Among them, stability to light is an especially important item, but the conventional functional layer has a problem that the active energy ray curable resin layer is easily peeled off from the cellulose acylate film when irradiated for a long time. Was demanded.

As a means for improving the light resistance of the resin film, it is common to add an ultraviolet absorber or an antioxidant. For example, in Patent Document 2, a hindered amine light stabilizer is added to the ultraviolet curable hard coat resin layer. A resin film is disclosed. Patent Document 3 discloses a cellulose acylate film containing a hindered amine antioxidant.
On the other hand, in Patent Documents 4 to 6, when an active energy ray-curable resin layer is coated on a cellulose acylate film, the cellulose acylate is dissolved and swollen by components in the active energy ray-curable resin layer coating solution. And a method for improving the adhesion is disclosed.

JP 2005-206721 A JP 2003-94573 A JP 2009-208358 A JP 2006-106714 A JP 2007-272214 A JP 2009-122172 A

However, when the present inventors examined the methods described in Patent Documents 2 and 3, the films obtained by these methods were adhered between the functional layer and the cellulose acylate film when light was irradiated for a long time. It was found that the property was insufficient.
The present invention has been made in view of such circumstances, and the problem to be solved by the present invention is that the adhesion between the active energy ray-curable resin layer and the cellulose acylate film is sufficient even when light is irradiated for a long period of time. It is to provide a polarizing plate protective film that is maintained and excellent in scratch resistance. Another object of the present invention is to provide a polarizing plate and a liquid crystal display device using the polarizing plate protective film.

  Conventionally, the adhesion between the active energy ray-curable resin layer and the cellulose acylate film is caused by the affinity between the active energy ray-curable resin layer surface and the cellulose acylate film, and / or the degree of crosslinking in the active energy ray-curable layer. It was considered an important factor. However, as a result of intensive studies by the present inventors, peeling between the active energy ray-curable resin layer and the cellulose acylate film occurs due to brittle fracture of the cellulose acylate film surface layer and / or the active energy ray-curable resin layer surface layer. I figured out that there was a case. Furthermore, the present inventors have found that the brittle fracture is caused by radicals generated by the photoreaction of the additive in the active energy ray-curable resin layer or the cellulose acylate film, and the resin (cellulose acylate) in the cellulose acylate film and / or It was also found that the cause is that the resin constituting the active energy ray-curable resin layer is depolymerized.

  The inventors of the present invention are effective in adding a Hindamine-based antioxidant for the depolymerization, and in order to maximize the effect of the hindered amine-based antioxidant, a cellulose acylate film and an active energy ray are used. It is effective to provide a mixed layer in which the cellulose acylate and the active energy ray curable resin are mixed between the cured resin layer and to optimize the mixed state of the cellulose acylate and the active energy ray curable resin. I found out. That is, the hindered amine compound needs to suppress the depolymerization of both the cellulose acylate and the active energy ray curable resin by light, but the cellulose acylate and the active energy ray curable resin are not mixed at all (that is, the above mixture). In the case where there is no layer or the mixed layer is present but its thickness is extremely thin), it has been found that the hindered amine compound may not be able to suppress depolymerization of the active energy ray-curable resin by light. . On the other hand, if the cellulose acylate and the active energy ray curable resin are mixed too much (that is, if the mixed layer is too thick), the hindered amine compound diffuses throughout the active energy ray curable resin, so the concentration is reduced and the radical scavenging effect is obtained. It turned out that it becomes weak and it becomes impossible to suppress depolymerization enough.

That is, the present invention has the following configuration.
[1]
A cellulose acylate film containing a hindered amine compound;
An active energy ray-curable resin layer;
Between the cellulose acylate film and the active energy ray curable resin layer, a mixed layer containing cellulose acylate and an active energy ray curable resin,
A polarizing plate protective film having a thickness ratio of 0.05 to 0.80 in the mixed layer represented by the following general formula (1).
General formula (1)
(Mixed layer thickness ratio) = (Mixed layer thickness) / [(Mixed layer thickness) + (Active energy ray cured resin layer thickness)]
[2]
The polarizing plate protective film according to [1], wherein the mixed layer contains a hindered amine compound.
[3]
The polarizing plate protective film according to [1] or [2], wherein the thickness of the active energy ray-curable resin layer is 0.5 μm or more and 20 μm or less.
[4]
A polarizer layer and at least one polarizing plate protective film are included, and the polarizing plate protective film according to any one of [1] to [3] is arranged such that the surface opposite to the active energy layer is close to the polarizer. A polarizing plate characterized in that it is attached to the surface.
[5]
A liquid crystal display device comprising at least one polarizing plate protective film according to any one of [1] to [3] or a polarizing plate according to [4].

  According to the present invention, even when light is irradiated for a long period of time, the adhesion between the active energy ray-curable resin layer and the cellulose acylate film is sufficiently maintained. Can be maintained, and a polarizing plate protective film having excellent scratch resistance can be 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.

Hereinafter, 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.

[Polarizing plate protective film]
The polarizing plate protective film of the present invention includes a cellulose acylate film containing a hindered amine compound, an active energy ray curable resin layer, and a cellulose acylate between the cellulose acylate film and the active energy ray curable resin layer. And a thickness ratio of the mixed layer represented by the following general formula (1) is 0.05 or more and 0.80 or less.
General formula (1)
(Mixed layer thickness ratio) = (Mixed layer thickness) / [(Mixed layer thickness) + (Active energy ray cured resin layer thickness)]
Preferably, the mixed layer includes a hindered amine compound.

The thickness ratio of the mixed layer can be controlled by a material used for the active energy ray-curable resin layer, a solvent, a substitution degree of cellulose acylate, a dope solvent, an additive, a film forming method, and the like.
First, the cellulose acylate film which the polarizing plate protective film of this invention has is demonstrated.

1. Cellulose acylate film The cellulose acylate film used for the polarizing plate protective film of the present invention contains cellulose acylate and a hindered amine compound. In view of controlling the thickness ratio of the mixed layer, it preferably contains at least one plasticizer.
Hereinafter, the cellulose acylate film used in the present invention will be described.

<1-1: Cellulose acylate>
Cellulose acylate raw material cellulose used in the cellulose acylate film includes cotton linter and wood pulp (hardwood pulp, conifer pulp), and any cellulose acylate obtained from any raw material cellulose can be used. You may mix and use. 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. When two or more types of acyl groups are used, one of them is preferably an acetyl group, and the acyl group having 2 to 4 carbon atoms is preferably a propionyl group or a butyryl 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.

  First, 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 allyl group, and is not particularly limited. These are, for example, cellulose alkylcarbonyl esters, alkenylcarbonyl esters, aromatic carbonyl esters, aromatic alkylcarbonyl esters, and the like, each of which may further have a substituted group. Preferred examples of these are acetyl group, propionyl group, butanoyl group, heptanoyl group, hexanoyl group, octanoyl group, decanoyl group, dodecanoyl group, tridecanoyl group, tetradecanoyl group, hexadecanoyl group, octadecanoyl group, isobutanoyl group. Group, tert-butanoyl group, cyclohexanecarbonyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group and the like. 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 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 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, CHIMASORB 2020FDL (CAS-No. 192268-64-7), CHIMASSORB 944FDL (CAS-No. 71878-19-8), TINUVIN 123 (manufactured by BASF (former Ciba Specialty Chemicals)) CAS-No. 129757-67-1) and TINUVIN 770DF (CAS-No. 52829-07-9), Siasorb UV-3346 (CAS-No. 82541-48-7) manufactured by Sun Chemical Co., Ltd., and Siasorb UV- 3529 (CAS-No. 193098-40-7) is commercially available and excellent in availability, and thus suitable.

  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 vicinity of the interface between the active energy ray-curable resin layer and the cellulose acylate film and the mixing thereof. In order to make the hindered amine compound unevenly distributed in the layer, a high molecular weight is preferable. 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 molecular weight of 300 to 100,000, more preferably 700 to 50,000, and particularly preferably 2,000 to 30,000.

The cellulose acylate film preferably contains 0.001% by mass or more of a hindered amine compound relative to the cellulose acylate. The hindered amine compound is more preferably contained in an amount of 0.001% by mass to 15% by mass with respect to the cellulose acylate, further preferably 0.01% by mass or more and 10% by mass or less, and more preferably 0.05% by mass. The content is particularly preferably 5% by mass or less.
By setting the content of the hindered amine compound to 0.001% by mass or more based on the cellulose acylate film, the hindered amine compound is appropriately diffused into the mixed layer between the active energy ray-curable resin layer and the cellulose acylate film, and the active energy Adhesion between the wire curable resin layer and the cellulose acylate film can be sufficiently secured. In addition, in the case of 15 mass% or less, it becomes difficult to produce a bleed-out of a hindered amine compound, and it is preferable from the viewpoint of improving the polarization performance of the polarizing plate.

<1-3: Plasticizer>
The cellulose acylate film according to the present invention preferably contains a kind of plasticizer from the viewpoint of controlling the thickness ratio of the mixed layer. Examples of the plasticizer include carbohydrate derivatives and polycondensed esters. In particular, a polycondensed ester is preferable.

(Carbohydrate derivative plasticizer)
The carbohydrate derivative as a plasticizer is preferably a monosaccharide or a carbohydrate derivative containing 2 to 10 monosaccharide units (hereinafter referred to as a carbohydrate derivative plasticizer).

The monosaccharide or polysaccharide preferably constituting the carbohydrate derivative plasticizer is characterized in that a substitutable group in the molecule (for example, a hydroxyl group, a carboxyl group, an amino group, a mercapto group, etc.) is substituted. Examples of structures formed by substitution include alkyl groups, aryl groups, and acyl groups. In addition, an ether structure formed by substituting a hydroxyl group with an alkyl group, an ester structure formed by substituting a hydroxyl group with an acyl group, an amide structure or an imide structure formed by substituting with an amino group can be exemplified. .
Examples of the monosaccharide or the carbohydrate containing 2 to 10 monosaccharide units include, for example, erythrose, threose, ribose, arabinose, xylose, lyxose, allose, altrose, glucose, fructose, mannose, gulose, idose, galactose , Talose, trehalose, isotrehalose, neotrehalose, trehalosamine, caudibiose, nigerose, maltose, maltitol, isomaltose, sophorose, laminaribiose, cellobiose, gentiobiose, lactose, lactosamine, lactitol, lactulose, melibiose, primebelloose, rutiose , Sucrose, sucralose, turanose, vicyanose, cellotriose, cacotriose, gentianose, isomalt Lyose, isopanose, maltotriose, manninotriose, melezitoose, panose, planteose, raffinose, solatriose, umbelliferose, lycotetraose, maltotetraose, stachyose, baltopentaose, velval course, maltohexaose, Examples include α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, δ-cyclodextrin, xylitol, sorbitol and the like.

  Preferably, ribose, arabinose, xylose, lyxose, glucose, fructose, mannose, galactose, trehalose, maltose, cellobiose, lactose, sucrose, sucralose, α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, δ-cyclodextrin Xylitol, sorbitol, more preferably arabinose, xylose, glucose, fructose, mannose, galactose, maltose, cellobiose, sucrose, β-cyclodextrin, γ-cyclodextrin, more preferably xylose, glucose, fructose Mannose, galactose, maltose, cellobiose, sucrose, xylitol, sorbitol, particularly preferred It is sucrose.

Examples of the substituent of the carbohydrate derivative plasticizer include an alkyl group (preferably an alkyl group having 1 to 22 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms, for example, Methyl group, ethyl group, propyl group, hydroxyethyl group, hydroxypropyl group, 2-cyanoethyl group, benzyl group, etc.), aryl group (preferably having 6 to 24 carbon atoms, more preferably 6 to 18 carbon atoms, particularly preferably 6 to 6 carbon atoms). 12 aryl groups such as phenyl and naphthyl groups, acyl groups (preferably having 1 to 22 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, such as acetyl groups, (Propionyl, butyryl, pentanoyl, hexanoyl, octanoyl, benzoyl, toluyl, phthalyl, naphthal, etc.) It can be mentioned. Further, as a preferred structure formed by substitution with an amino group, an amide structure (preferably an amide having 1 to 22 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, such as formamide, acetamide, etc. And imide structure (preferably having 4 to 22 carbon atoms, more preferably 4 to 12 carbon atoms, and particularly preferably 4 to 8 carbon atoms, such as succinimide and phthalimide).
Among these, an alkyl group, an aryl group or an acyl group is more preferable, and an acyl group is particularly preferable.

Preferable examples of the carbohydrate derivative plasticizer include the following. However, the carbohydrate derivative plasticizer that can be used in the present invention is not limited to these.
Xylose tetraacetate, glucose pentaacetate, fructose pentaacetate, mannose pentaacetate, galactose pentaacetate, maltose octaacetate, cellobiose octaacetate, sucrose octaacetate, xylitol pentaacetate, sorbitol hexaacetate, xylose tetrapropionate, glucose pentapropioate , Fructose pentapropionate, mannose pentapropionate, galactose pentapropionate, maltose octapropionate, cellobiose octapropionate, sucrose octapropionate, xylitol pentapropionate, sorbitol hexapropionate, Xylose tetrabutyrate, glucose pentab Rate, fructose pentabylate, mannose pentabylate, galactose pentabylate, maltose octabutyrate, cellobiose octabutyrate, sucrose octabutyrate, sucrose acetate isobutyrate, xylitol pentabylate, sorbitol hexabutyrate, xylosetetra Benzoate, glucose pentabenzoate, fructose pentabenzoate, mannose pentabenzoate, galactose pentabenzoate, maltose octabenzoate, cellobiose octabenzoate, sucrose benzoate (such as sucrose octabenzoate), xylitol pentabenzoate, sorbitol hexabenzoate and the like are preferable. Xylose tetraacetate, glucose pentaacetate, fructose pentaacetate, mannose pentaacetate, galactose pentaacetate, maltose octaacetate, cellobiose octaacetate, sucrose octaacetate, xylitol pentaacetate, sorbitol hexaacetate, xylose tetrapropionate, glucose pentapropioate , Fructose pentapropionate, mannose pentapropionate, galactose pentapropionate, maltose octapropionate, cellobiose octapropionate, sucrose octapropionate, xylitol pentapropionate, sorbitol hexapropionate, Sucrose acetate isobutyrate, xylose Tiger benzoate, glucose pentabenzoate, fructose pentabenzoate, mannose pentabenzoate, galactose pentabenzoate, maltose octabenzoate, cellobiose octabenzoate, sucrose benzoate (sucrose octa benzoate), xylitol pentabenzoate, sorbitol hexabenzoate is more preferable. Maltose octaacetate, cellobiose octaacetate, sucrose octaacetate, xylose tetrapropionate, glucose pentapropionate, fructose pentapropionate, mannose pentapropionate, galactose pentapropionate, maltose octapropionate, cellobiose octane Propionate, sucrose octapropionate, sucrose acetate isobutyrate, xylose tetrabenzoate, glucose pentabenzoate, fructose pentabenzoate, mannose pentabenzoate, galactose pentabenzoate, maltose octabenzoate, cellobiose octabenzoate, sucrose benzoate (sucrose octabenzoate Etc.), Xylito Le pentabenzoate, sorbitol hexabenzoate are particularly preferred.
The carbohydrate derivative hydrophobizing agent preferably has a pyranose structure or a furanose structure.

  As the carbohydrate derivative used in the present invention, the following compounds are particularly preferred. However, the carbohydrate derivatives that can be used in the present invention are not limited to these. In the following structural formulas, R represents “Substituent 1” or “Substituent 2”, and “Degree of substitution” represents the number of “Substituent 1” or “Substituent 2”.

(how to get)
As a method for obtaining the carbohydrate derivative, it can be obtained as a commercial product from Tokyo Kasei Co., Ltd., Aldrich, etc., or known ester derivatization methods for commercially available carbohydrates (for example, JP-A-8-245678). Can be synthesized by carrying out the method described in the publication.

  The carbohydrate derivative-based plasticizer can be obtained as a commercially available product from Tokyo Kasei Co., Ltd., Aldrich, etc., or known ester derivatization methods for commercially available carbohydrates (for example, JP-A-8 The method can be synthesized by the method described in JP-A-245678.

(Polycondensed ester plasticizer)
The polycondensation ester as a plasticizer is obtained from at least one dicarboxylic acid having an aromatic ring (also referred to as aromatic dicarboxylic acid) and at least one aliphatic diol having an average carbon number of 2.5 to 8.0. It is preferred that Moreover, it is also preferable to obtain from the mixture of aromatic dicarboxylic acid and at least 1 type of aliphatic dicarboxylic acid, and at least 1 type of aliphatic diol whose average carbon number is 2.5-8.0.

Calculation of the average carbon number of the dicarboxylic acid residue is performed separately for the dicarboxylic acid residue and the diol residue.
The value calculated by multiplying the constituent carbon number by the composition ratio (molar fraction) of the dicarboxylic acid residue is defined as the average carbon number. For example, when the adipic acid residue and the phthalic acid residue are composed of 50 mol% each, the average carbon number is 7.0.
The same applies to the diol residue, and the average carbon number of the diol residue is a value calculated by multiplying the constituent carbon number by the composition ratio (molar fraction) of the diol residue. For example, when it is composed of 50 mol% of ethylene glycol residues and 50 mol% of 1,2-propanediol residues, the average carbon number is 2.5.

The number average molecular weight of the polycondensed ester is preferably 500 to 2000, more preferably 600 to 1500, and still more preferably 700 to 1200. If the number average molecular weight of the polycondensed ester is 600 or more, the volatility is low, and film failure or process contamination due to volatilization under high temperature conditions during stretching of the cellulose ester film is unlikely to occur. Moreover, if it is 2000 or less, compatibility with a cellulose ester will become high, and it will become difficult to produce the bleed-out at the time of film forming and the heat-stretching.
The number average molecular weight of the polycondensed ester can be measured and evaluated by gel permeation chromatography. Further, in the case of a polyester polyol having an unsealed terminal, it can also be calculated from the amount of hydroxyl groups per weight (hereinafter also referred to as hydroxyl value). In the present invention, the hydroxyl value is determined by measuring the amount (mg) of potassium hydroxide required for neutralizing excess acetic acid after acetylating the polyester polyol.

When a mixture of an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid is used as the dicarboxylic acid component, the dicarboxylic acid component is preferably a dicarboxylic acid having an average carbon number of 5.5 to 10.0, more preferably 5 .6-8.
If the average carbon number is 5.5 or more, a polarizing plate having excellent durability can be obtained. If the average number of carbon atoms is 10 or less, the compatibility with the cellulose ester is excellent, and the occurrence of bleed out can be suppressed in the process of forming the cellulose ester film.

The polycondensation ester obtained from a diol and a dicarboxylic acid containing an aromatic dicarboxylic acid contains an aromatic dicarboxylic acid residue.
In the present specification, a residue is a partial structure of a polycondensed ester and represents a partial structure having the characteristics of a monomer forming the polycondensed ester. For example, the dicarboxylic acid residue formed from dicarboxylic acid HOOC-R-COOH is -OC-R-COO-.
The aromatic dicarboxylic acid residue ratio of the polycondensed ester used in the present invention is preferably 40 mol% or more, and more preferably 40 mol% to 95 mol%.
By setting the aromatic dicarboxylic acid residue ratio to 40 mol% or more, a cellulose ester film exhibiting sufficient optical anisotropy can be obtained, and a polarizing plate excellent in durability can be obtained. Moreover, if it is 95 mol% or less, it is excellent in compatibility with a cellulose ester, and it can make it hard to produce a bleed-out also at the time of film forming of a cellulose ester film, and the time of heat-stretching.

Examples of the aromatic dicarboxylic acid that can be used to form the polycondensed ester plasticizer that can be used in the present invention include phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4- Examples thereof include naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,8-naphthalenedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid. Of these, phthalic acid, terephthalic acid, and 2,6-naphthalenedicarboxylic acid are preferable, phthalic acid and terephthalic acid are more preferable, and terephthalic acid is still more preferable.
An aromatic dicarboxylic acid residue derived from the aromatic dicarboxylic acid used for mixing is formed in the polycondensed ester.
That is, the aromatic dicarboxylic acid residue preferably includes at least one of a phthalic acid residue, a terephthalic acid residue, and an isophthalic acid residue, more preferably at least one of a phthalic acid residue and a terephthalic acid residue. A seed, more preferably a terephthalic acid residue.
By using terephthalic acid as the aromatic dicarboxylic acid for mixing in the formation of the polycondensed ester, it is more compatible with the cellulose ester, and bleed-out is less likely to occur during film formation and heat stretching of the cellulose ester film. It can be set as a cellulose ester film. The aromatic dicarboxylic acid may be used alone or in combination of two or more. When two types are used, it is preferable to use phthalic acid and terephthalic acid.
By using together two kinds of aromatic dicarboxylic acids of phthalic acid and terephthalic acid, the polycondensation ester at normal temperature can be softened, which is preferable in terms of easy handling.
The content of the terephthalic acid residue in the dicarboxylic acid residue of the polycondensed ester is preferably 40 mol% to 100 mol%.
By setting the terephthalic acid residue ratio to 40 mol% or more, a cellulose ester film exhibiting sufficient optical anisotropy can be obtained.

A polycondensation ester obtained from a diol and a dicarboxylic acid containing an aliphatic dicarboxylic acid contains an aliphatic dicarboxylic acid residue.
Examples of the aliphatic dicarboxylic acid that can form a polycondensation ester hydrophobizing agent that can be preferably used in the present invention include oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, and adipic acid. , Pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid or 1,4-cyclohexanedicarboxylic acid.
In the polycondensed ester, an aliphatic dicarboxylic acid residue derived from the aliphatic dicarboxylic acid used for mixing is formed.
The aliphatic dicarboxylic acid residue preferably has an average carbon number of 5.5 to 10.0, more preferably 5.5 to 8.0, and preferably 5.5 to 7.0. Further preferred. If the average carbon number of the aliphatic dicarboxylic acid residue is 10.0 or less, the heat loss of the compound can be reduced, and the occurrence of surface failure that may be caused by process contamination due to bleed-out during drying of the cellulose acylate web is prevented. be able to. Moreover, it is preferable that the aliphatic dicarboxylic acid residue has an average carbon number of 5.5 or more because it is excellent in compatibility and precipitation of the polycondensed ester hardly occurs.
Specifically, the aliphatic dicarboxylic acid residue preferably includes a succinic acid residue, and when two types are used, it preferably includes a succinic acid residue and an adipic acid residue.
That is, one kind of aliphatic dicarboxylic acid or two or more kinds may be used for mixing in the formation of the polycondensed ester. When two kinds are used, it is preferable to use succinic acid and adipic acid. When one kind of aliphatic dicarboxylic acid is used for mixing in the formation of the polycondensed ester, it is preferable to use succinic acid. The average carbon number of the aliphatic dicarboxylic acid residue can be adjusted to a desired value, which is preferable in terms of compatibility with the cellulose ester.

  In the present invention, it is also preferable to use two or three dicarboxylic acids for mixing in the formation of the polycondensed ester. When using two kinds, it is preferable to use one kind of aliphatic dicarboxylic acid and one kind of aromatic dicarboxylic acid. When using three kinds, one kind of aliphatic dicarboxylic acid and two kinds of aromatic dicarboxylic acid or aliphatic dicarboxylic acid are used. Two kinds of acids and one kind of aromatic dicarboxylic acid can be used. This is because the average carbon number value of the dicarboxylic acid residue can be easily adjusted, the content of the aromatic dicarboxylic acid residue can be within a preferable range, and the durability of the polarizer can be improved.

The polycondensation ester obtained from diol and dicarboxylic acid contains a diol residue.
In the present specification, the diol residue formed from the diol HO—R—OH is —O—R—O—.
Examples of the diol that forms the polycondensed ester include aromatic diols and aliphatic diols. The polycondensed ester used in the hydrophobizing agent used in the present invention is preferably formed from at least an aliphatic diol.
The polycondensed ester preferably contains an aliphatic diol residue having an average carbon number of 2.5 to 7.0, more preferably an aliphatic diol residue having an average carbon number of 2.5 to 4.0. Including. When the average carbon number of the aliphatic diol residue is less than 7.0, the compatibility with the cellulose ester is improved, bleed-out is less likely to occur, and the heat loss of the compound is less likely to be increased. It is difficult for surface failures that are thought to be caused by process contamination during drying to occur. Further, the synthesis is easy if the average carbon number of the aliphatic diol residue is 2.5 or more.
Preferred examples of the aliphatic diol that can form the polycondensation ester hydrophobizing agent that can be used in the present invention include alkyl diols and alicyclic diols, such as ethylene glycol, 1,2, and the like. -Propanediol, 1,3-propanediol, 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-hexa Diol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10- Decanediol, 1,12-octadecanediol, diethylene glycol, cyclohexanedimethanol and the like are preferable. These are preferably used together with ethylene glycol as one or a mixture of two or more.

More preferably, the aliphatic diol is at least one of ethylene glycol, 1,2-propanediol, and 1,3-propanediol, and particularly preferably at least one of ethylene glycol and 1,2-propanediol. It is. In the case where the polycondensation ester is formed using two kinds of the aliphatic diol, it is preferable to use ethylene glycol and 1,2-propanediol. By using 1,2-propanediol or 1,3-propanediol, crystallization of the polycondensed ester can be prevented.
In the polycondensed ester, a diol residue is formed by the diol used for mixing.
That is, the polycondensation ester preferably contains at least one of an ethylene glycol residue, a 1,2-propanediol residue, and a 1,3-propanediol residue as a diol residue. More preferably, it is a 1,2-propanediol residue.
The aliphatic diol residue contained in the polycondensed ester preferably contains 10 mol% to 100 mol%, more preferably 20 mol% to 100 mol% of ethylene glycol residue.

The terminal of the polycondensed ester may be left as it is without being blocked, and may be left as a diol or carboxylic acid, or may be further blocked with a so-called terminal by reacting with a monocarboxylic acid or monoalcohol.
As monocarboxylic acids used for sealing, acetic acid, propionic acid, butanoic acid, benzoic acid and the like are preferable. As monoalcohols used for sealing, methanol, ethanol, propanol, isopropanol, butanol, isobutanol and the like are preferable, and methanol is most preferable. When the number of carbon atoms of the monocarboxylic acid used at the terminal of the polycondensed ester is 7 or less, the loss on heating of the compound does not increase, and no surface failure occurs.
More preferably, the end of the polycondensed ester remains as a diol residue without being sealed, or is sealed with acetic acid, propionic acid or benzoic acid.
It does not matter whether both ends of the polycondensed ester have the same sealing performance.
When both ends of the condensate are unsealed, the polycondensed ester is preferably a polyester polyol.
One aspect of the polycondensed ester is a polycondensed ester in which the aliphatic diol residue has 2.5 to 8.0 carbon atoms, and both ends of the polycondensed ester are unblocked.
When both ends of the polycondensed ester are sealed, it is preferably sealed by reacting with a monocarboxylic acid. At this time, both ends of the polycondensed ester are monocarboxylic acid residues. In the present specification, the monocarboxylic acid residue formed from the monocarboxylic acid R-COOH is R-CO-. When both ends of the polycondensed ester are sealed with a monocarboxylic acid, the monocarboxylic acid is preferably an aliphatic monocarboxylic acid residue, and the monocarboxylic acid residue is an aliphatic monocarboxylic acid having 22 or less carbon atoms. It is more preferably a carboxylic acid residue, and even more preferably an aliphatic monocarboxylic acid residue having 3 or less carbon atoms. In addition, an aliphatic monocarboxylic acid residue having 2 or more carbon atoms is preferable, and an aliphatic monocarboxylic acid residue having 2 carbon atoms is particularly preferable.
In one embodiment of the polycondensation ester, the aliphatic diol residue has a carbon number of more than 2.5 and 7.0 or less, and both ends of the polycondensation ester are capped with monocarboxylic acid residues. Mention may be made of condensed esters.
When the carbon number of the monocarboxylic acid residue sealing both ends of the polycondensed ester is 3 or less, the volatility is lowered, the weight loss due to heating of the polycondensed ester is not increased, and the occurrence of process contamination It is possible to reduce the occurrence of planar failures.
That is, the monocarboxylic acid used for sealing is preferably an aliphatic monocarboxylic acid, more preferably an aliphatic monocarboxylic acid having 2 to 22 carbon atoms, and an aliphatic monocarboxylic acid having 2 to 3 carbon atoms. A carboxylic acid is more preferable, and an aliphatic monocarboxylic acid residue having 2 carbon atoms is particularly preferable.
For example, acetic acid, propionic acid, butanoic acid, benzoic acid and derivatives thereof are preferable, acetic acid or propionic acid is more preferable, and acetic acid is most preferable.
Two or more monocarboxylic acids used for sealing may be mixed.
Both ends of the polycondensed ester are preferably sealed with acetic acid or propionic acid, and most preferably both ends are acetyl ester residues (sometimes referred to as acetyl residues).
When both ends of the polycondensed ester are sealed, a cellulose ester film that is difficult to be in a solid state at normal temperature, has good handling, and is excellent in humidity stability and polarizing plate durability can be obtained.

  Specific examples J-1 to J-40 of the polycondensed ester are shown in Tables 5 and 6 below, but the present invention is not limited to these.

  The abbreviations in the above Table 5 and Table 6 represent the following compounds, respectively. PA: phthalic acid, TPA: terephthalic acid, AA: adipic acid, SA: succinic acid, 2,6-NPA: 2,6-naphthalenedicarboxylic acid.

  The synthesis of the polycondensed ester is performed either by a conventional method, a hot melt condensation method by a polyesterification reaction or transesterification reaction between a diol and a dicarboxylic acid, or an interfacial condensation method between an acid chloride of these acids and glycols Can be easily synthesized. The polycondensation ester is described in detail in Koichi Murai, “Plasticizers, Theory and Application” (Kobo Publishing Co., Ltd., first published on March 1, 1973). In addition, Japanese Patent Laid-Open Nos. 05-155809, 05-155810, Japanese Patent Laid-Open Nos. 05-97073, 2006-259494, 07-330670, 2006-342227, 2007-003679. The materials described in each publication can also be used.

  It is preferable that the addition amount of these plasticizers is 1-20 mass% with respect to a cellulose acylate. If the content is 1% by mass or more, the effect of improving the durability of the polarizer can be easily obtained, and if the content is 20% by mass or less, bleeding out hardly occurs. A more preferable addition amount is 2 to 15% by mass, and particularly preferably 5 to 15% by mass.

  Moreover, it is also preferable to use 2 or more types of plasticizers from the viewpoint of controlling the thickness ratio of the mixed layer. In this case, the two kinds of plasticizers are preferably those having a rigid structure (for example, a terephthalic acid group) and those having a flexible structure (for example, a terephthalic acid group or a linear aliphatic group). 1-15 mass% is preferable with respect to a cellulose acylate, and, as for the addition amount of the former plasticizer, 2-10 mass% is more preferable. 1-15 mass% is preferable with respect to a cellulose acylate, and, as for the addition amount of the latter plasticizer, 2-10 mass% is more preferable.

  The timing for adding these plasticizers to the cellulose acylate film is not particularly limited as long as it is added at the time of film formation. For example, it may be added at the time of cellulose acylate synthesis, or may be mixed with cellulose acylate during dope preparation.

<1-4: Other additives>
In the cellulose acylate film, additives such as an ultraviolet absorber; an antioxidant other than the hindered amine compound; and a matting agent may be added.

(Antioxidant)
In the present invention, a known antioxidant for the cellulose acylate solution such as 2,6-di-tert-butyl-4-methylphenol, 4,4′-thiobis- (6-tert-butyl-3-methylphenol) is used. ), 1,1′-bis (4-hydroxyphenyl) cyclohexane, 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 2,5-di-tert-butylhydroquinone, pentaerythrityl-tetrakis A phenolic or hydroquinone antioxidant such as [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 the cellulose resin.

(UV absorber)
In the present invention, an ultraviolet absorber may be added to the cellulose acylate solution from the viewpoint of preventing deterioration of the polarizing plate or the liquid crystal. As the ultraviolet absorber, those excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less and having little absorption of visible light having a wavelength of 400 nm or more are preferably used from the viewpoint of good liquid crystal display properties. Specific examples of ultraviolet absorbers preferably used in the present invention include, for example, hindered phenol compounds, hydroxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds Etc. Examples of hindered phenol compounds include 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]. N, N′-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert) -Butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-tert-butyl-4-hydroxybenzyl) -isocyanurate and the like. Examples of benzotriazole compounds include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6 (2H-benzotriazol-2-yl) phenol), (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5- Triazine, triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], N, N′-hexamethylenebis (3,5-di-tert-butyl-4- Hydroxy-hydrocinnamide), 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole, (2 (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) -5 -Chlorobenzotriazole, 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] and the like. The addition amount of these ultraviolet light inhibitors is preferably 1 ppm to 1.0%, more preferably 10 to 1000 ppm in terms of mass ratio with respect to cellulose acylate in the cellulose acylate film.

(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 which aims at a retardation film with little additive bleed-out, no delamination phenomenon, good 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 mass, and included in a proportion of 0.03 to 3.0% by mass with respect to the cellulose acylate. More preferably, it is particularly preferably included at a ratio of 0.05 to 1.0% by mass.

<1-5: Configuration and physical properties of cellulose acylate film>
(Layer structure of film)
The cellulose acylate film may be a single layer or a laminate of two or more layers.
When the cellulose acylate film is a laminate of two or more layers, a two-layer structure or a three-layer structure is more preferable, and a three-layer structure is preferable. In the case of a three-layer structure, a layer in contact with the metal support (hereinafter also referred to as a support surface or a skin B layer) when the film of the present invention is produced by solution casting, and the side opposite to the metal support It is preferable to have an air interface layer (hereinafter also referred to as an air surface or a skin A layer) and a single core layer sandwiched therebetween. That is, the film of the present invention preferably has a three-layer structure of skin B layer / core layer / skin A layer.

(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)
In the cellulose acylate film, the average thickness of the low substitution layer is preferably 30 to 100 μm, more preferably 30 to 80 μm, and further preferably 30 to 70 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 the said core layer is 30-70 micrometers, It is more preferable that it is 30-60 micrometers, It is 30-50 micrometers. Is particularly preferred. When the film of the present invention has a laminated 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 0.5 to 20 μm, preferably 0.5 to It is particularly preferably 10 μm, and more preferably 0.5 to 3 μm.

(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.

<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.

(Organic solvent for cellulose acylate solution)
In the present invention, the film is preferably produced using a solution (dope) obtained by dissolving cellulose acylate in an organic solvent. The organic solvent preferably used as the main solvent of the present invention is preferably a solvent selected from esters, ketones, ethers having 3 to 12 carbon atoms, and halogenated hydrocarbons having 1 to 7 carbon atoms. The ester, ketone and ether may have a cyclic structure. A compound having two or more functional groups of esters, ketones and ethers (that is, —O—, —CO— and —COO—) can also be used as a main solvent, such as an alcoholic hydroxyl group. It may have a functional group of In the case of the main solvent having two or more kinds of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group.

For the cellulose acylate film of the present invention, chlorine-based halogenated hydrocarbon is used as a main solvent (good solvent), and at least one monovalent alcohol having 10 or less carbon atoms is mixed as a poor solvent. Are preferably used. The secondary structure of cellulose acylate on the surface of the cellulose acylate film can be changed by changing the number of carbon atoms of the alcohol to be mixed and the mixing ratio with respect to the main solvent. The thickness of the mixed layer after application can be adjusted. That is, the higher the poor solvent ratio, the thicker the mixed layer thickness.
As the good solvent of the present invention, methylene chloride is particularly preferable, and as the poor solvent, methanol, ethanol, and n-butanol are particularly preferable. The mass ratio of methylene chloride to the alcohol is preferably 98/2 or more and 70/30, and more preferably 95/5 or more and 78/22 or less. By making the mass ratio of methylene chloride and the alcohols in the above range, the thickness ratio of the mixed layer after application of the active energy ray-curable resin layer without causing a surface failure of the film due to insoluble matter derived from cellulose acylate Can be adjusted to the desired ratio.

(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 the formation of the cellulose acylate film, it is preferable to use a laminating casting method such as a co-casting method, a sequential casting method, and a coating method. In particular, the simultaneous co-casting method is preferably used to reduce stable production and production costs. From the viewpoint of
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.
FIG. 2 is a cross-sectional view showing a state in which the co-casting giesser 3 is used to simultaneously extrude and cast the surface layer dope 1 and the core layer dope 2 on the casting support 4.

  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 surface layer, and then applied to the film one side at a time or both sides simultaneously using an appropriate applicator. This is a method of forming a film having a laminated structure by applying and drying a liquid.

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).

  The secondary structure of cellulose acylate in the cellulose acylate film can also be changed by changing the temperature of the support during dope casting, and the thickness of the mixed layer after application of the active energy ray-curable resin layer is adjusted. be able to. The support temperature during the production of the cellulose acylate film of the present invention is preferably from -15 ° C to 30 ° C, and more preferably from -10 ° C to 25 ° C. By setting the support temperature within the above range, the thickness of the mixed layer after application of the active energy ray-curable resin layer can be adjusted while maintaining the uniformity of the film. When the support temperature is lowered, a cellulose acylate film having a large free volume can be produced, and the thickness of the mixed layer can be increased.

(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, the cellulose acylate film of the present invention preferably has improved wavelength dispersion characteristics, but it becomes possible to impart such optical performance by stretching treatment, and further, the cellulose acylate film has a desired property. It is possible to impart retardation. 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 5% to 200%, more preferably 10% to 100%, and particularly preferably 20% 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. This is not the case when the cast 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 further 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 curable resin layer The polarizing plate protective film of the present invention has an active energy ray curable resin layer laminated on the cellulose acylate film. In this specification, the active energy ray-curable resin layer refers to a layer containing a resin that can be cured by active energy rays, and the resin is cured by active energy rays.
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-curable resin layer will be described.

<2-1: Kind of active energy ray cured resin layer>
The active energy ray-curable resin 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 curable resin layer is a functional layer such as a forward scattering layer, an antiglare (antiglare) layer, a gas barrier layer, a slipping layer, an antistatic layer, an undercoat layer, a hard coat layer, an antireflection layer or a protective layer. Preferably there is.
The active energy ray-curable resin layer is more preferably an antireflection layer or a hard coat layer, and particularly preferably a hard coat layer.
In addition, these functional layers are used in combination in the same layer as the antireflection layer in the antireflection film other than the active energy ray-curable resin layer or the optically anisotropic layer in other viewing angle compensation films. It is also preferable.
These active energy ray-curable resin 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). .
The thickness of the active energy ray-curable resin layer is preferably 0.5 μm or more and 20 μm or less.

Hereinafter, the functional layer used as the active energy ray-curable resin layer in the present invention will be described.
The polarizing plate protective film of the present invention is characterized by having at least one active energy ray-curable resin 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-curable resin layer may be provided, or a plurality of layers may be provided. The plurality of active energy ray curable resin layers may be the same or different.

(1) Hard coat layer The polarizing plate protective film of the present invention is preferably provided on the surface of the cellulose acylate film as an active energy ray-curable resin layer in order to impart mechanical strength such as scratch resistance. .
The thickness of the hard coat layer is preferably 0.5 to 20 μm, more preferably 1.0 to 15 μm, and particularly preferably 1.5 to 10 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-curable resin 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. 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 with the forward scattering layer as an active energy ray-curable resin 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 with the antiglare layer as an active energy ray-curable resin 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: Method for producing active energy ray-curable resin layer>
There is no restriction | limiting in particular as a formation method of the said active energy ray hardening resin layer, A well-known method can be used. Among these, it is preferable to form the active energy ray-curable resin layer in which the material for dissolving the active energy ray-curable resin layer is 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 ester solvent, a hydrocarbon solvent, or an alcohol solvent.
Examples of the solvent include MiBK (methyl isobutyl ketone), MEK (methyl ethyl ketone), cyclohexanenon, ethyl acetate, toluene, ethanol, and the like.
From the viewpoint of controlling the thickness ratio of the mixed layer, cyclohexanone, ethyl acetate, and ethanol are preferable.
Two or more solvents can be used. In that case, at least one is preferably cyclohexanone, ethyl acetate, or ethanol.
In the coating solution for an active energy ray-curable resin layer, the amount of the solvent is preferably 20 to 80% by mass, and more preferably 30 to 70% by mass.

Although there is no restriction | limiting in particular also about the specific method of coating the said active energy ray cured resin 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-curable resin layer is more preferably active energy rays such as radiation, γ rays, α rays, electron rays, and ultraviolet rays among active energy rays, and considering safety and productivity, It is particularly preferable to use 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). There is no particular restriction on the strength and the like of the active energy ray, for example, in the case of ultraviolet irradiation, intensity 10 to 1000 mW / cm ^2, it is preferred to an irradiation dose of 50 to 5000 mJ / cm ^2.

<2-4: Measurement of thickness of mixed layer>
The polarizing plate protective film of the present invention has a layer (mixed layer) in which the active energy ray-curable resin and the cellulose acylate are mixed between the active energy ray-curable resin layer and the cellulose acylate film.
When the active energy ray-curable resin layer coating solution is applied onto the cellulose acylate film to form the active energy ray-curable resin layer, the mixed layer is an interface between the cellulose acylate film and the active energy ray-curable resin layer. Then, it is formed by mixing cellulose acylate and active energy ray curable resin.
As described above, the thickness ratio of the mixed layer can be controlled by a material used for the active energy ray-curable resin layer, a solvent, a substitution degree of cellulose acylate, a dope solvent, an additive, a film forming method, and the like.
The presence of the mixed layer improves the adhesion between the active energy ray-curable resin layer and the cellulose acylate film. On the other hand, if the mixed layer is too thick, there is a problem that the pencil hardness is lowered. Therefore, the thickness of the mixed layer of the polarizing plate protective film of the present invention is preferably such that the mixed layer thickness ratio represented by the following general formula (1) is 0.05 or more and 0.8 or less. More preferably, it is 0.1 or more and 0.60 or less.
General formula (1)
(Mixed layer thickness ratio) = (Mixed layer thickness) / [(Mixed layer thickness) + (Active energy ray cured resin layer thickness)]
The thickness ratio of the mixed layer can be determined by cutting the obtained film, etching the cross section, observing with a SEM, and measuring the thickness of each layer.

[Polarizer]
The present invention also relates to a polarizing plate using at least one polarizing plate protective film of the present invention.
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. 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.

[Example 101]
(1) Production of cellulose acylate film <Preparation of cellulose acylate>
A cellulose acylate having an acetyl substitution degree of 2.88 was prepared. This was carried out by adding sulfuric acid (7.8 parts by mass with respect to 100 parts by mass of cellulose) as a catalyst, adding carboxylic acid as a raw material for the acyl substituent, and carrying out an acylation reaction at 40 ° C. In addition, aging was performed at 40 ° C. after acylation. Further, the low molecular weight component of the cellulose acylate was removed by washing with acetone.

(Preparation of cellulose acylate solution (dope))
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 ――――――――――――――――――――――――――――――――――――
Cellulose acetate with an acetyl substitution degree of 2.88 and a polymerization degree of 350
100.0 parts by mass Plasticizer 1 (described in Table 7) 2.0 parts by mass Plasticizer 2 (described in Table 7) 6.0 parts by mass antioxidant (CHIMASSORB 944FDL (manufactured by BASF))
0.2 parts 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. The prepared dope was cast on a stainless casting support (support temperature 20 ° C.). Stripped in a state where the amount of residual solvent in the dope is approximately 40% by mass, held both ends in the width direction of the film with a tenter, and stretched in the transverse direction by 1.15 times 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) Formation of active energy ray-curable resin layer <Preparation of coating solution for active energy ray-curable resin layer (HC-1)>
Each component was produced with the composition shown below, and filtered through a polypropylene filter having a pore diameter of 30 μm to prepare a coating liquid HC-1 for active energy ray-curable resin layer.

―――――――――――――――――――――――――――――――――――
Composition of coating solution HC-1 for active energy ray curable resin layer ―――――――――――――――――――――――――――――――――――
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 Ciba Specialty Chemicals)
―――――――――――――――――――――――――――――――――――

<Formation of active energy ray-curable resin layer>
On the surface that was in contact with the support during the formation of the cellulose acylate film formed above, the coating solution for active energy ray-curable resin layer (HC-1) was transported at a speed of 30 m by the microgravure coating method. The coating was performed under the conditions of / min. 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 an active energy ray curable resin layer.
The obtained polarizing plate protective film with active energy ray-curable resin layer was used as the polarizing plate protective film of Example 101.

<Measurement of mixed layer thickness ratio>
The polarizing plate protective film obtained above is cut, the cross section is etched, and then observed with an SEM, the thickness of the active energy ray-curable resin layer and the thickness of the mixed layer are measured, and mixed according to the following general formula (1) The layer ratio was calculated. The thicknesses of the active energy ray-curable resin layer and the mixed layer and the thickness ratio of the mixed layer in each example and comparative example are shown in Table 8 below.
General formula (1)
(Mixed layer thickness ratio) = (Mixed layer thickness) / [(Mixed layer thickness) + (Active energy ray cured resin layer thickness)]

(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 active energy ray-curable resin 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 121 and Comparative Examples 201 to 208]
[Production of Polarizing Plate Protective Films of Examples 102 to 121 and Comparative Examples 201 to 208]
In Example 101, Table 7 shows the substitution degree of cellulose acylate, the kind and addition amount of plasticizer, the composition of the dope solvent, the casting support temperature, the thickness of the cellulose acylate film, and the composition of the active energy ray-curable resin layer. The polarizing plate protective film of Examples 102-121 and Comparative Examples 201-206 was manufactured similarly except having changed as it was. In Comparative Examples 207 and 208, a dope in which cellulose acylate or the like was dissolved could not be prepared, and a cellulose acylate film and a polarizing plate protective film could not be produced.
Although the composition of the active energy ray-curable resin layer is not described in Table 7, Irgacure 184 (polymerization initiator) is used in Example 101 as the active energy ray-curable resin layer coating liquid in each Example and Comparative Example. Used in the same way.

  In addition, in the following Table 7, the addition amount of the plasticizer 1, the plasticizer 2, and the antioxidant represents a part by mass with respect to 100 parts by mass of the cellulose acylate resin. In Table 7 below, CHIMASSORB 944FDL, CHIMASSORB 2020FDL, and TINUVIN123 are manufactured by BASF.

[Saponification of polarizing plate protective film and preparation of polarizing plate]
For the polarizing plate protective films of Examples 102 to 121 and the polarizing plate protective films of Comparative Examples 201 to 206, saponification treatment and production of polarizing plates were performed in the same manner as in Example 101, and the polarized light of each Example and Comparative Example was used. A plate was made.

[Evaluation]
<Evaluation of adhesion>
First, with respect to the polarizing plate protective film with an active energy ray-curable resin layer of each Example and Comparative Example prepared above, a Super Xenon Weather Meter SX75 manufactured by Suga Test Instruments Co., Ltd., 60 ° C., 50% relative humidity. The light was irradiated for 100 hours in the environment.
Next, the polarizing plate protective film with an active energy ray-curable resin layer was conditioned for 2 hours under conditions of a temperature of 25 ° C. and a relative humidity of 60%. On the surface having the active energy ray-cured resin layer, 11 vertical and 11 horizontal cuts are made in a grid pattern with a cutter knife, and a total of 100 square squares are engraved on the surface. Nitto Denko Corporation ) Made of polyester adhesive tape (No. 31B). 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.
○: 1 to 20 mm peeling was observed at 100 mm.
(Triangle | delta): The peeling of 21-40cm was recognized in 100%.
X: Peeling of 41 mm or more was observed at 100 mm.
The obtained results are shown in Table 8 below.

<Evaluation of pencil hardness>
The pencil hardness evaluation described in JIS K 5400 was performed. After the polarizing plate protective film was conditioned for 2 hours at a temperature of 25 ° C. and a humidity of 60% RH, the test was performed 20 times with a load of 500 g using a 3H test pencil specified in JIS S 6006 as follows. It was evaluated by the judgment. The obtained results are shown in Table 8 below.
○: No scratch was observed in 13 to 20 experiments.
Δ: No scratch was observed in 6 to 12 experiments.
X: The test by which the damage | wound was not recognized was 5 times or less.

  From the results of Table 8 above, the polarizing plate using the polarizing plate protective film of the present invention hardly peels between the active energy ray-curable resin layer and the cellulose acylate film even when irradiated with light for a long time. It was also found to be excellent in scratch resistance and preferable.

[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 the liquid crystal cell side. The transmission axis of the polarizing plate on the viewer side was arranged in the vertical direction.
Moreover, it replaced with the polarizing plate protective film of Example 101 in the above, and produced the liquid crystal display device of the comparative example similarly except having used the polarizing plate protective film of Comparative Examples 201-206.
The liquid crystal display device of the present invention thus produced is less susceptible to scratches on the surface of the display device than the liquid crystal display device using the polarizing plate protective film of each comparative example, and is exposed to direct sunlight outdoors. Even when used for a long time, the degradation of display quality was small.

Claims (5)

A cellulose acylate film containing a hindered amine compound;
An active energy ray-curable resin layer;
Between the cellulose acylate film and the active energy ray curable resin layer, a mixed layer containing cellulose acylate and an active energy ray curable resin,
A polarizing plate protective film having a thickness ratio of 0.05 to 0.80 in the mixed layer represented by the following general formula (1).
General formula (1)
(Mixed layer thickness ratio) = (Mixed layer thickness) / [(Mixed layer thickness) + (Active energy ray cured resin layer thickness)]   The polarizing plate protective film according to claim 1, wherein the mixed layer contains a hindered amine compound.   The polarizing plate protective film according to claim 1 or 2, wherein the thickness of the active energy ray-curable resin layer is 0.5 µm or more and 20 µm or less.   A polarizer layer and at least one polarizing plate protective film are included, and the polarizing plate protective film according to any one of claims 1 to 3 is attached so that the surface opposite to the active energy layer is close to the polarizer. A polarizing plate characterized by being struck.   A liquid crystal display device comprising at least one polarizing plate protective film according to claim 1 or at least one polarizing plate according to claim 4.