JP2017066288A - Cellulose acylate film, polarizing plate and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cellulose acylate film that acts as new means to improve durability of a polarizer.SOLUTION: The cellulose acylate film comprises a compound containing at least one fluorine-containing group selected from the group consisting of -CF, -CFH and -CF- in one molecule and at least one urethane bond in one molecule. The cellulose acylate film shows a peak intensity ratio (PA/PB) in the range from 0 to 0.90, which is a ratio of a peak intensity PA at a wavenumber of 1740 cmobtained by measuring an infrared absorption spectrum on one surface A of the cellulose acylate film to a peak intensity PB at a wavenumber of 1740 cmobtained by measuring an infrared absorption spectrum on the other surface B of the cellulose acylate film. A polarizing plate and a liquid crystal display device are also disclosed.SELECTED DRAWING: None

Description

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

  Cellulose acylate films are widely used as films constituting display devices such as liquid crystal display devices. Conventionally, it has been studied to improve the performance of such a cellulose acylate film (see, for example, Patent Documents 1 and 2).

JP, 2015-0667629, A WO2015 / 012407A1

  Useful applications of the cellulose acylate film include use as a polarizing plate protective film. The polarizing plate includes at least a polarizer, and usually a protective film (polarizing plate protective film) is laminated on one or both surfaces of the polarizer in order to prevent the polarizer from being damaged. In a liquid crystal display device, a polarizing plate plays a role of selectively transmitting light having a polarization plane in a certain direction, and a function for this role is exhibited by a polarizer.

  In recent years, in addition to indoor use, liquid crystal display devices have increased opportunities to be used outdoors (for example, large screen displays and portable devices installed outdoors). Therefore, the polarizing plate constituting the liquid crystal display device has high durability that can withstand use in various environments including outdoors (specifically, even if used in various environments, the above-mentioned role is achieved). (Hereinafter also referred to as “polarizing plate durability”), and there is an increasing need for polarizing plates having extremely excellent polarizing plate durability exceeding the normally required level.

  As a means for improving the durability of the polarizing plate, it is conceivable to increase the durability of the polarizer itself. However, any change to the polarizer (change in composition, change in manufacturing method, etc.) to improve the durability of the polarizer itself may cause changes in the performance of the polarizer. It is not easy to improve durability while maintaining the above. From this point, it can be said that it is desirable that the polarizing plate protective film can contribute to improvement of polarizing plate durability.

  The objective of this invention is providing the cellulose acylate film used as the new means which enables improvement of polarizing plate durability.

One embodiment of the present invention provides:
A cellulose acylate film,
A compound containing one or more fluorine-containing groups selected from the group consisting of —CF ₃ , —CF ₂ H, and —CF ₂ — in one molecule and one or more urethane bonds in one molecule (hereinafter, “ It is also referred to as “urethane bond-containing compound”).
The peak intensity PA at a wave number of 1740 cm ⁻¹ determined by infrared absorption spectrum measurement on one surface A of the cellulose acylate film, and the wave number of 1740 cm determined by infrared absorption spectrum measurement on the other surface B of the cellulose acylate film. ^A cellulose acylate film in which the peak intensity ratio with respect to the peak intensity PB at ^-1 , PA / PB is in the range of 0 to 0.90,
About.

  In one embodiment, the concentration ratio FA / FB between the fluorine concentration FA determined on the surface A by photoelectron spectroscopic analysis and the fluorine concentration FB determined on the surface B by photoelectron spectroscopic analysis is in the range of 0 to 0.90.

  In one embodiment, the compound contains two or more of the fluorine-containing groups in one molecule.

  In one embodiment, the compound contains two or more urethane bonds in one molecule.

  In one aspect | mode, the said compound contains 2-6 urethane bonds in 1 molecule.

  In one embodiment, the compound has a partial structure in which a urethane bond is directly connected to an aromatic ring. In the present invention and this specification, with respect to the connection between a certain group or partial structure, “direct connection” means a direct bond without any other atom such as a connection group between those groups or partial structures. It means that you are doing.

  In one embodiment, the aromatic ring is a benzene ring.

  In one aspect, in the partial structure, the urethane bond is directly connected to the aromatic ring by a nitrogen atom contained in the urethane bond.

  In one embodiment, the compound has one or two of the partial structures per molecule.

  In one embodiment, the molecular weight of the compound is 200 or more and 2000 or less.

  In one aspect | mode, the said cellulose acylate film contains 0.1-50.0 mass parts of said compounds with respect to 100.0 mass parts of cellulose acylates.

  The further aspect of this invention is related with the polarizing plate containing the said cellulose acylate film and a polarizer.

  In one aspect, the polarizer is an iodine dyed polyvinyl alcohol film.

  The further aspect of this invention is related with the liquid crystal display device containing the said polarizing plate and a liquid crystal cell.

  In one aspect, the liquid crystal display device includes the polarizing plate as at least a viewing-side polarizing plate.

  According to one embodiment of the present invention, a cellulose acylate film useful as a polarizing plate protective film, a polarizing plate having excellent polarizing plate durability including the film, and a liquid crystal display device including the polarizing plate can be provided.

It is a schematic diagram (partial enlarged view) which shows an example of the casting die used for the manufacturing method (co-casting) of a cellulose acylate film. It is a schematic diagram (partial enlarged view) which shows an example of the manufacturing method (co-casting) of a cellulose acylate film.

  The contents of the present invention will be described in detail below. In the present invention and the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

[Cellulose acylate film]
The cellulose acylate film according to one embodiment of the present invention (hereinafter, also simply referred to as “film”) is
A compound containing one or more fluorine-containing groups selected from the group consisting of —CF ₃ , —CF ₂ H, and —CF ₂ — in one molecule and one or more urethane bonds in one molecule;
The peak intensity PA at a wave number of 1740 cm ⁻¹ determined by infrared absorption spectrum measurement on one surface A of the cellulose acylate film, and the wave number of 1740 cm determined by infrared absorption spectrum measurement on the other surface B of the cellulose acylate film. ^A cellulose acylate film in which the peak intensity ratio with respect to the peak intensity PB at ^-1 , PA / PB is in the range of 0 to 0.90,
It is.

The inventor presumes the cellulose acylate film as follows.
The peak at a wave number of 1740 cm ⁻¹ in the infrared absorption spectrum is an absorption peak derived from C═O contained in the urethane bond, and the peak intensity of this absorption peak is used as an index of the abundance of the compound containing the urethane bond. Can do. The more compounds containing a urethane bond, the greater the peak intensity of the absorption peak. If the compound containing a urethane bond is evenly distributed throughout the film, the peak intensity of the peak measured on one surface of the film and the peak intensity of the peak measured on the other surface are not significantly different. The peak intensity ratio PA / PB is close to 1.
On the other hand, the cellulose acylate film has a peak intensity ratio (PA) between the peak intensity PA measured on one surface (surface A) and the peak intensity PB measured on the other surface (surface B). / PB) is from 0 to 0.90. This is because the peak intensity measured on the surface B is larger than the peak intensity measured on the surface A, that is, the urethane bond-containing compound is unevenly distributed on the surface B side (hereinafter, unevenly distributed). Is also referred to as “uneven distribution”). The inventor of the present invention provides that the urethane bond-containing compound contained in the cellulose acylate film contains one fluorine-containing group selected from the group consisting of —CF ₃ , —CF ₂ H, and —CF ₂ — in one molecule. I think that including more than one brings about this ubiquity. Specifically, the fluorine-containing group contributes to lowering the surface energy of the compound, and thereby the urethane bond-containing compound tends to be unevenly distributed on the air interface side in the drying step during film production. The present inventor speculates that this may be brought about. And it is thought that the moisture permeability of this film falls because the surface (surface B) suppresses permeation | transmission of the water to a film by uneven distribution of said urethane bond containing compound. As a result, by using this film as a polarizing plate protective film, the ability to reduce moisture reaching the polarizer from the external atmosphere may lead to maintenance of the performance of the polarizer, that is, improvement of polarizing plate durability. Thinks.
However, the above is only an estimation and does not limit the present invention.

  Below, the said cellulose acylate film is demonstrated in detail.

<Peak intensity ratio PA / PB>
The peak intensity PA at a wave number of 1740 cm ⁻¹ determined by infrared absorption spectrum measurement on one surface (surface A) of the cellulose acylate film, and the wave number of 1740 cm determined by infrared absorption spectrum measurement on the other surface (surface B). The peak intensity ratio (PA / PB) with the peak intensity PB at ^-1 is 0 to 0.90. In this way, the presence of the urethane bond-containing compound on one surface (surface B) side contributes to a decrease in the moisture permeability of the film, and by using this film as a polarizing plate protective film, polarizing plate durability The present inventor has inferred that the improvement of the property becomes possible. The peak intensity ratio (PA / PB) means that the urethane bond (the urethane bond-containing compound) is unevenly distributed on the surface B side as the value decreases, and is in the range of 0 to 0.70. Preferably, the range is from 0 to 0.50, more preferably from 0 to 0.10, even more preferably from 0 to 0.08, and from 0 to 0.05. The range is even more preferable. The peak intensity ratio (PA / PB) is, for example, 0.01 or more, but may be zero.

The peak intensity ratio (PA / PB) is a value measured by the following method.
A film sample (for example, 1 cm × 1 cm size cut out from a film) is measured by ATR-IR (Attenuated Total Reflection-infrared spectroscopy) according to the following procedure. An infrared absorption spectrum is obtained.
1. A test piece is prepared by pressing and fixing the surface of the film sample on the ATR prism with a jig.
2. After setting the ATR prism surface of the test piece toward the light source inside the ATR-IR apparatus, infrared absorption spectrum measurement is performed by irradiating infrared rays (IR). Note that a Ge (germanium) prism is used for IR irradiation, and the incident angle is 45 °. In addition, measurement is performed with 64 times of accumulation while flowing dry air. As the blank value, a value in air (a state in which no test piece is introduced into the ATR-IR apparatus) is adopted.
In the infrared absorption spectrum thus obtained, the peak intensity at a wave number of 1740 cm ⁻¹ , which is a peak derived from C═O contained in the urethane bond, is obtained as a difference (actual measurement value−blank value) between the actual measurement value and the blank value.
3. The above operations 1 and 2 are performed on both sides of the film sample, and the average value of the measured number of integrations of 64 times is obtained for both sides, and the ratio between the average value of peak intensity PA and the average value of peak intensity PB is obtained. The peak intensity ratio (PA / PB) is obtained.

<Concentration ratio FA / FB>
In the cellulose acylate film, it is also desirable that the F (fluorine) concentration on the surface B side is higher than the surface A side because the urethane bond-containing compound containing the fluorine-containing group is unevenly distributed on the surface B side. Specifically, the fluorine concentration on the surface A side (hereinafter referred to as “FA”) and the fluorine concentration on the surface B side (hereinafter referred to as “FB”) measured by X-ray photoelectron spectroscopy analysis. Is preferably in the range of 0 to 0.90. The concentration ratio (FA / FB) is more preferably in the range of 0 to 0.70, further preferably in the range of 0 to 0.50, and still more preferably in the range of 0 to 0.10. The range of 0 to 0.08 is even more preferable, and the range of 0 to 0.05 is even more preferable. The concentration ratio (FA / FB) is, for example, 0.01 or more, but may be zero.

The concentration ratio (FA / FB) is a value measured by the following method.
A film sample (for example, 1 cm × 1 cm size cut out from the film) is obtained by XPS (X-ray Photoelectron Spectroscopy) according to the following procedure to determine the fluorine concentration on one surface side and the other surface side. .
1. A test piece is prepared by fixing the surface of the film sample to be measured to the air interface side and fixing the surface opposite to the air interface side to the sample table. A test piece is placed in the sample introduction section of the XPS apparatus and evacuated to adjust the degree of vacuum.
2. After adjusting the degree of vacuum to about 1 × 10 ⁻⁵ Pa, the test piece is moved to the apparatus measurement unit.
3. Using a monochromated Al-Kα ray (1486.6 eV, 25 W, 15 kV) as an X-ray light source and using a neutralizing gun with Pass Energy = 55 eV, to any location on the air interface surface of the test piece X-rays are irradiated and reflected photoelectrons are detected and measured.
4). The above operations 1 to 3 are carried out at 10 arbitrary positions on both sides of the film sample, and the average value of the measured values at 10 positions is obtained for both sides, and the average value of the fluorine concentration FA and the average value of the fluorine concentration FB. The concentration ratio (FA / FB) is obtained as the ratio with FB.

<Urethane bond-containing compound>
The urethane bond-containing compound contained in the cellulose acylate film has one or more urethane bonds (—NH—C (═O) —O—) in one molecule. From the viewpoint of further reducing the film moisture permeability, the number of urethane bonds contained in one molecule is preferably 2 or more, preferably 2 to 6, and 2 to 4. Is more preferable.

When the urethane bond-containing compound contains two or more urethane bonds in one molecule, adjacent urethane bonds may be directly connected, may be connected via a linking group, or may be connected via a linking group. Preferably it is. Examples of the linking group that connects adjacent urethane bonds include m-valent linking groups. Here, m is an integer of 2 or more, and m urethane bonds can be linked through an m-valent linking group. For example, as a divalent linking group,
_{* - (CH 2) a- *} (a is an integer ranging from 1 to 10.)
The alkylene group represented by these can be mentioned. Here, * indicates a bonding position with a urethane bond. In addition, examples of the linking group include the following linking groups. Also in the following, * shows a coupling | bonding position with a urethane bond. The linking group can be bonded to a nitrogen atom or an oxygen atom contained in the urethane bond in *, and is preferably bonded to the nitrogen atom.

The urethane bond-containing compound contains one or more fluorine-containing groups selected from the group consisting of —CF ₃ , —CF ₂ H, and —CF ₂ — in addition to the urethane bond. As described above, the present inventors speculate that the inclusion of this fluorine-containing group contributes to the uneven distribution of the urethane bond-containing compound on one surface of the film. Furthermore, since the fluorine-containing group is a hydrophobic group, the presence of this group is considered to contribute to a decrease in film moisture permeability. Note -CF 3 _{(trifluoromethyl)} and -CF 2 H _{(difluoromethyl} group) may be included as a molecular terminal group of the urethane compound, in a side chain of the substituent group for substituting the main chain It may be included. On the other hand, -CF ₂ - (perfluoro-methylene group) is, - _(CF 2) n-(perfluoroalkylene group; a n is an integer of 2 or more, for example in a range from 2 to 10, the range preferably of 2 to 6 And may be contained in the urethane bond-containing compound.

The fluorine-containing group may be directly connected to a urethane bond or may be connected via a linking group. In addition, the fluorine-containing groups may be directly connected to each other or may be connected via a connecting group.
Examples of the linking group include, but are not limited to, alkylene groups having 1 to 10 carbon atoms. Further, a linking group (—CFH—) in which one of two hydrogen atoms contained in a methylene group is substituted with a fluorine atom can also be mentioned as a preferred linking group.

The urethane bond-containing compound preferably contains one or more fluorine-containing groups selected from the group consisting of —CF ₃ , —CF ₂ H, and —CF ₂ — in one molecule, and preferably contains two or more. More preferably, 6 are included, and 2-4 are still more preferable.

  The urethane bond-containing compound preferably includes one or more cyclic structures in the structure. Examples of the cyclic structure include an aliphatic ring (such as a cyclohexane ring) and an aromatic ring (such as a benzene ring and a naphthalene ring), and may be an aromatic heterocycle. An aromatic heterocycle refers to a cyclic structure containing a hetero atom in the aromatic ring. An example is a triazine ring. The cyclic structure may be a single ring or a condensed ring. Two or more ring structures may be directly connected or may be connected via a connecting group. As the linking group, reference can be made to the above description regarding a linking group capable of linking fluorine-containing groups or fluorine-containing groups and urethane bonds.

  As a preferable embodiment of the urethane bond-containing compound, a compound having a partial structure in which a urethane bond is directly connected to an aromatic ring can be exemplified. It is preferable that one or two such partial structures are contained in one molecule of the urethane bond-containing compound.

  In the partial structure, the urethane bond is more preferably linked to the aromatic ring by a nitrogen atom contained in the urethane bond. More preferably, the aromatic ring is a benzene ring. Specific examples of the partial structure include the following structures. In the following, * indicates a bonding position with another structure constituting the compound.

  Moreover, it is also preferable that the partial structures are connected to each other via a connecting group. As an example, the following structure can be exemplified in which two urethane bonds are linked via a divalent linking group in which two benzene rings are linked via a methylene group.

  Specific examples of the urethane bond-containing compound include the following exemplary compounds A to H.

  Furthermore, the following compounds can also be illustrated as specific examples of the urethane bond-containing compound. However, the present invention is not limited to the exemplified compounds.

The molecular weight of the urethane bond-containing compound is preferably 2000 or less, more preferably 1500 or less, and still more preferably 1000 or less, from the viewpoint of compatibility with cellulose acylate. Further, from the viewpoint of low volatility, the molecular weight is preferably 200 or more, and more preferably 300 or more.
When the above compound is a polymer, the molecular weight means a weight average molecular weight unless otherwise specified. The average molecular weight (weight average molecular weight, number average molecular weight) in the present invention and the present specification refers to a value measured in terms of polystyrene by gel permeation chromatography (GPC). Examples of specific measurement conditions include the following measurement conditions. The average molecular weight shown in the below-mentioned examples is a value measured under the following conditions.
GPC device: HLC-8320 (manufactured by Tosoh Corporation):
Column: TSK gel SuperHZM-H, TSK gel SuperHZ4000, TSK gel SuperHZ2000 combined use (manufactured by Tosoh, 4.6 mm ID (inner diameter) x 15.0 cm)
Eluent: Tetrahydrofuran (THF)

  The urethane bond-containing compound described above can be produced by a known method.

(Content)
The cellulose acylate film preferably contains 0.1 to 50.0 parts by mass, and 0.5 to 30.0 parts by mass of the urethane bond-containing compound with respect to 100.0 parts by mass of cellulose acylate. It is more preferable that 1.0 to 20.0 parts by mass is included, and 2.0 to 15.0 parts by mass is particularly preferable. About the aspect which uses together 2 or more types of compounds as said urethane bond containing compound, said content shall say the total amount of 2 or more types of compounds.

<Cellulose acylate>
The cellulose acylate film contains cellulose acylate together with the urethane bond-containing compound. In the cellulose acylate film, the component (main component) occupying the most is preferably cellulose acylate. The cellulose acylate content of the cellulose acylate film can be, for example, about 50 to 95% by mass with respect to the film mass, but is not limited thereto.

As the cellulose acylate, a known cellulose acylate used for producing a cellulose acylate film can be used without any limitation. The degree of substitution of cellulose acylate means the ratio of acylation of three hydroxy groups present in the structural unit of cellulose (glucose having a (β) 1,4-glycoside bond). The degree of substitution (acylation degree) can be calculated by measuring the amount of bound fatty acid (or bound carboxylic acid) per unit mass of cellulose. In the present invention and this specification, the degree of substitution of the cellulose body is determined by measuring the ¹³ C-NMR spectrum by dissolving the cellulose body in a solvent such as dimethyl sulfoxide substituted with deuterium, and measuring the peak of the carbonyl carbon in the acyl group. It can be calculated by obtaining from the intensity ratio. It can be determined by ¹³ C-NMR measurement after substituting the remaining hydroxy group of cellulose acylate with another acyl group different from the acyl group of cellulose acylate itself. Details of the measurement method are described in Tezuka et al. (Carbohydrate. Res., 273 (1995) 83-91).

  The substitution degree of cellulose acylate is preferably 1.50 or more and 3.00 or less, more preferably 2.00 to 2.97, and further preferably 2.30 or more and less than 2.97. It is particularly preferably 2.30 to 2.95.

In the cellulose acetate using only acetyl group as the acyl group of cellulose acylate, the degree of substitution is preferably 2.00 or more and 3.00 or less, more preferably 2.20 to 3.00. It is preferably 2.30 to 3.00, more preferably 2.30 to 2.97, and particularly preferably 2.30 to 2.95.
As the acyl group of cellulose acylate, an acetyl group, a propionyl group, and a butyryl group are preferable, and an acetyl group is more preferable.

A mixed fatty acid ester composed of two or more acyl groups can also be preferably used as the cellulose acylate in one embodiment of the present invention. Also in this case, the acyl group is preferably an acetyl group and an acyl group having 3 to 4 carbon atoms. Moreover, when using mixed fatty acid ester, when an acetyl group is included as an acyl group, the substitution degree is preferably less than 2.5, and more preferably less than 1.9. On the other hand, the substitution degree in the case of containing an acyl group having 3 to 4 carbon atoms is preferably 0.1 to 1.5, more preferably 0.2 to 1.2, and 0.5 to 1 .1 is particularly preferred.
In one embodiment of the present invention, two types of cellulose acylates having different substituents and / or degree of substitution may be used in combination or mixed, or different cellulose acylates may be used by the co-casting method described later. You may form the film which consists of several layers which consist of.

  Furthermore, mixed acid esters having fatty acid acyl groups and substituted or unsubstituted aromatic acyl groups described in paragraphs 0023 to 0038 of JP-A-2008-20896 can also be preferably used in one embodiment of the present invention.

  The cellulose acylate preferably has a weight average degree of polymerization of 250 to 800, and more preferably has a weight average degree of polymerization of 300 to 600. In addition, the cellulose acylate used in one embodiment of the present invention preferably has a number average molecular weight of 40000 to 230,000, more preferably 60000 to 230,000, and a number average molecular weight of 75000 to 200000. Most preferred.

  Cellulose acylate can be synthesized using an acid anhydride or acid chloride as an acylating agent. When the acylating agent is an acid anhydride, an organic acid (for example, acetic acid) or methylene chloride is used as a reaction solvent. Further, a protic catalyst such as sulfuric acid can be used as the catalyst. When the acylating agent is an acid chloride, a basic compound can be used as a catalyst. In the most common synthetic method in the industry, cellulose is an organic acid corresponding to acetyl group and other acyl groups (acetic acid, propionic acid, butyric acid) or their acid anhydrides (acetic anhydride, propionic anhydride, butyric anhydride). Cellulose acylate is synthesized by esterification with a mixed organic acid component containing.

  In the above method, cellulose such as cotton linter and wood pulp is activated with an organic acid such as acetic acid, and then in the presence of a sulfuric acid catalyst, the mixture of organic acid components as described above is used. Often esterified. The organic acid anhydride component is generally used in excess relative to the amount of hydroxy groups present in the cellulose. In this esterification treatment, in addition to the esterification reaction, a hydrolysis reaction (depolymerization reaction) of the cellulose main chain (β) 1,4-glycoside bond) proceeds. When the hydrolysis reaction of the main chain proceeds, the degree of polymerization of the cellulose acylate is lowered, and the physical properties of the cellulose acylate film to be produced are lowered. For this reason, the reaction conditions such as the reaction temperature are preferably determined in consideration of the degree of polymerization and molecular weight of the cellulose acylate obtained.

<Additives optionally contained in cellulose acylate film>
The cellulose acylate film may contain other additives in addition to the urethane bond-containing compound and the cellulose acylate. Examples of the additive include known plasticizers, organic acids, dyes, polymers, retardation adjusting agents, ultraviolet absorbers, antioxidants, matting agents, and the like. About these, description of Paragraph Nos. 0062-0097 of JP, 2012-155287, A can be referred to, and these contents are built into this specification. Examples of the additive include a peeling accelerator, an organic acid, and a polyvalent carboxylic acid derivative. Regarding these, the description of International Publication WO2015 / 005398, paragraphs 0212 to 0219 can be referred to, and the contents thereof are incorporated in the present specification.
The content of additives (when the cellulose acylate film contains two or more additives, the total content thereof) is 50.0 parts by mass or less with respect to 100.0 parts by mass of cellulose acylate. Preferably, it is 30.0 parts by mass or less.

(Plasticizer)
One preferred additive is a plasticizer. By adding a plasticizer, the hydrophobicity of the cellulose acylate film can be further increased. The molecular weight of the plasticizer is preferably 3000 or less, more preferably 1500 or less, and still more preferably 1000 or less, from the viewpoint of obtaining the above-described effect by adding it satisfactorily. The molecular weight of the plasticizer is, for example, 300 or more, preferably 350 or more, from the viewpoint of low volatility. As for the plasticizer for the polymer, the molecular weight means the number average molecular weight.

  As the plasticizer, a polyhydric ester compound of polyhydric alcohol (hereinafter also referred to as “polyhydric alcohol ester plasticizer”), a polycondensed ester compound (hereinafter also referred to as “polycondensed ester plasticizer”), And carbohydrate compounds (hereinafter also referred to as “carbohydrate derivative plasticizers”). For polyhydric alcohol ester plasticizers, paragraphs 0081 to 0098 of JP2014-077130, for polycondensed ester plasticizers, paragraphs 00099 to 0124, and for carbohydrate derivative plasticizers, paragraphs 0125 to 0140 of the publication. You can refer to it. The content of these plasticizers is 1.0 to 20.0 parts by mass with respect to 100.0 parts by mass of cellulose acylate from the viewpoint of achieving both the effect of adding the plasticizer and suppressing the precipitation of the plasticizer. Is more preferable, and it is more preferable to set it as 2.0-15.0 mass parts, and it is still more preferable to set it as 5.0-15.0 mass parts.

(Antioxidant)
One preferable additive may include an antioxidant. Regarding the antioxidant, the description of International Publication WO2015 / 005398, paragraphs 0143 to 0165 can be referred to, and the contents thereof are incorporated in the present specification.

(Radical scavenger)
One preferred additive is a radical scavenger. Regarding the radical scavenger, the description in paragraphs 0166 to 0199 of International Publication No. WO2015 / 005398 can be referred to, and the contents thereof are incorporated herein.

(Deterioration inhibitor)
As one of preferable additives, a deterioration preventing agent can be mentioned. Regarding the deterioration preventing agent, the description in paragraphs 0205 to 0206 of International Publication No. WO2015 / 005398 can be referred to, and the contents thereof are incorporated herein.

(Barbituric acid compound)
The cellulose acylate film may also contain a compound having a barbituric acid structure (barbituric acid compound). A barbituric acid compound is a compound which can express various functions in a cellulose acylate film by adding this compound. For example, a barbituric acid compound is effective for improving the hardness of a cellulose acylate film. The barbituric acid compound is also effective in improving the durability against light, heat, humidity and the like of a polarizing plate provided with a cellulose acylate film containing this compound. About the barbituric acid compound which can be added to the said cellulose acylate film, description of the international publication WO2015 / 005398 paragraph 0029-0060 paragraph can be referred, for example, These content is integrated in this specification.

<Method for producing cellulose acylate film>
The method for producing the cellulose acylate film is not particularly limited, but it is preferably produced by a melt film formation method or a solution film formation method (solvent cast method). It is more preferable to manufacture by a film forming method (solvent cast method). Examples of production of a cellulose acylate film using a solvent cast method are described in U.S. Pat. Nos. 2,336,310, 2,367,603, 2,492,078, and 2,492. No. 977, No. 2,492,978, No. 2,607,704, No. 2,739,069 and No. 2,739,070, British Patent No. 640731 and Refer to each specification of No. 736892, and Japanese Patent Publication Nos. 45-4554, 49-5614, JP-A-60-176634, 60-203430 and 62-1115035. Can do. Further, the cellulose acylate film may be subjected to a stretching treatment.

(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. There is a method using a reverse roll coater that adjusts with a reverse rotating roll, and a method using a pressure die is preferable. 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 polymer solution, and each condition is set in consideration of differences in the boiling point of the solvent used. be able to.

-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. .) Method is particularly preferred from the viewpoints of stable production and production cost reduction.
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), the dope for casting of each layer (which may be three layers or more) is simultaneously pressed from another 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. Using a co-casting giusa, three layers of the surface layer dope and the core layer dope can be extruded simultaneously on the casting support. FIG. 1 is a schematic diagram showing an example of a casting die used for co-casting. FIG. 2 is a schematic diagram (partially enlarged view) showing an example of co-casting. When casting the dope, as shown in FIG. 1, the dope is cast from the casting die 89 on the traveling band 85 so as to have a three-layer structure of skin layer A / core layer / skin layer B. As shown in FIG. 2, co-casting (simultaneous multilayer casting) can be performed. The core layer refers to a layer located in the center in a three-layer structure, and the skin layers A and B refer to layers located outside in a three-layer structure.

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. The dope for casting is extruded from the casting gear, and if necessary, the dope is successively cast and laminated to the third layer or more, and peeled off from the support at an appropriate time and dried. This is a casting method for forming a cellulose acylate film. In general, the core layer is formed into a film by a solution casting method, and a coating solution is prepared to be applied to the surface layer. In this method, a liquid is applied and dried to form a cellulose acylate film having a laminated structure.
A cellulose acylate film can be obtained by containing the urethane bond-containing compound in any one or more of these layers or in all layers.

(Extension process)
In the manufacturing method of a cellulose acylate film, it is preferable to include the process of extending | stretching formed into a film. The stretching direction of the cellulose acylate film is preferably either the cellulose acylate film transport direction (MD (Machine Direction) direction) or the direction orthogonal to the transport direction (TD (Transverse Direction) direction), but in the cellulose acylate film transport direction. An orthogonal direction (TD direction) is particularly preferable from the viewpoint of a polarizing plate processing process using a subsequent cellulose acylate film. In addition, you may perform a extending | stretching process in multiple steps in two steps or more.

  Methods for stretching in the TD 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 MD direction, for example, if the speed of the cellulose acylate film is adjusted so that the take-up speed of the cellulose acylate film is higher than the speed of peeling off the cellulose acylate film, the cellulose acylate film Is stretched. In the case of stretching in the TD direction, the cellulose acylate film can also be stretched by conveying while holding the width of the cellulose acylate film with a tenter and gradually increasing the width of the tenter. After the cellulose acylate film is dried, it can be stretched using a stretching machine (preferably uniaxial stretching using a long stretching machine).

  When the cellulose acylate film is used as a protective film for a polarizer (polarizing plate protective film), in order to suppress light leakage when the polarizing plate is viewed from an oblique direction, the transmission axis of the polarizer and the cellulose acylate film An embodiment in which in-plane slow axes are arranged in parallel is also preferred. Since the transmission axis of the roll film-like polarizer produced continuously is generally parallel to the width direction of the roll film, it is composed of the roll film-like polarizer and the roll film-like cellulose acylate film. In order to continuously bond the protective film, the in-plane slow axis of the roll film-shaped protective film needs to be parallel to the width direction of the cellulose acylate film. Therefore, it is also preferable to stretch more in the TD direction. The stretching process may be performed in the middle of the film forming process, or the original fabric that has been formed and wound may be stretched.

  The stretching in the TD direction is preferably 5 to 100%, more preferably 5 to 80%, particularly preferably 5 to 40%. In addition, unstretched means that stretching is 0%. The stretching process may be performed in the middle of the film forming process, or the original fabric that has been formed and wound may be stretched. In the former case, stretching may be performed in a state including the residual solvent amount, and the residual solvent amount = (residual volatile matter mass / heat-treated film mass) × 100% is preferably stretched at 0.05 to 50%. be able to. It is particularly preferable to perform 5 to 80% stretching in a state where the residual solvent amount is 0.05 to 5%.

<Physical properties of cellulose acylate film>
(Moisture permeability)
The moisture permeability of the cellulose acylate film is determined by measuring the mass of water vapor passing through the sample in 24 hours in an atmosphere at a temperature of 40 ° C. and a relative humidity of 90% according to JIS Z0208 moisture permeability test (cup method). it can be obtained as a value in terms of the mass of water vapor passing through the 24-hour per 1 m ^2.
Moisture permeability of the cellulose acylate film is preferably 500~1300g ^/ m 2 · day, more preferably from 500~1200g ^/ m 2 · day, it is 500~1000g ^/ m 2 · day More preferably, it is particularly preferably 500 to 900 g / m ² · day.
In the above-mentioned cellulose acylate film, the present inventors consider that the urethane bonds are unevenly distributed on one surface (surface B) side as described above, which contributes to a decrease in moisture permeability. The present inventors speculate that this is the reason why the polarizing plate durability can be improved by using a cellulose acylate film containing the above compound as a polarizing plate protective film.

(Film thickness)
The film thickness of a cellulose acylate film can be suitably determined according to the application, and is, for example, 5 to 100 μm. When the thickness is 5 μm or more, the handling property when producing a web-like film is improved, which is preferable. Moreover, by setting it as 100 micrometers or less, it becomes easy to respond to a humidity change and it becomes easy to maintain an optical characteristic. As for the film thickness of a cellulose acylate film, 8-80 micrometers is more preferable, and 10-70 micrometers is still more preferable.
Moreover, when the cellulose acylate film has a laminated structure of three or more layers, the thickness of the core layer is preferably 3 to 70 μm, more preferably 5 to 60 μm. When the cellulose acylate film has a three-layer structure, the thickness of the skin layer A and the skin layer B is preferably 0.5 to 20 μm, more preferably 0.5 to 10 μm, and more preferably 0.5 to 3 μm. Further preferred.

(width)
When producing a cellulose acylate film, the width is preferably 700 to 3000 mm, more preferably 1000 to 2800 mm, and particularly preferably 1300 to 2500 mm.

(Saponification treatment)
The cellulose acylate film can be used as a polarizing plate protective film by imparting adhesion to a polarizer material such as polyvinyl alcohol by alkali saponification treatment.
As a saponification method, for example, the methods described in paragraphs 0211 and 0212 of JP-A-2007-86748 can be used.

  For example, the alkali saponification treatment for the cellulose acylate film is preferably performed in a cycle in which the film surface is immersed in an alkali solution, neutralized with an acidic solution, washed with water and dried. Examples of the alkaline solution include a potassium hydroxide solution and a sodium hydroxide solution, and the concentration of hydroxide ions is preferably in the range of 0.1 to 5.0 mol / L, and preferably 0.5 to 4.0 mol / L. More preferably, it is in the range of L. The alkaline solution temperature is preferably in the range of room temperature to 90 ° C, and more preferably in the range of 40 to 70 ° C.

  Alternatively, instead of the alkali saponification treatment, easy adhesion processing as described in JP-A-6-94915 and JP-A-6-118232 may be applied to the cellulose acylate film.

[Polarizer]
(Configuration of polarizing plate)
The polarizing plate concerning one mode of the present invention has the above-mentioned cellulose acylate film and light polarizer.
In one aspect, the polarizing plate includes a polarizer and one polarizing plate protective film for protecting one side of the polarizer, or at least one of the cellulose acylate films, the polarizing plate protective film. Can have as.
In addition, the liquid crystal display device usually has a configuration in which a liquid crystal cell is disposed between the viewing side polarizing plate and the backlight side polarizing plate. In the viewing side polarizing plate and the backlight side polarizing plate, the polarizing plate protective film located between the polarizing plate and the liquid crystal cell is the inner side protective film, and the protective film located on the side opposite to the inner side is the outer side protective film. When it says, the above-mentioned cellulose acylate film can be used also as any protective film of the inner side of a visual recognition side polarizing plate, an outer side, the inner side of a backlight side polarizing plate, and an outer side.
Therefore, in one aspect, the cellulose acylate film is included in the liquid crystal display device as an outer-side polarizing plate protective film positioned on the surface opposite to the surface facing the liquid crystal cell of the polarizer.
Moreover, in another one aspect | mode, the said cellulose acylate film is contained in a liquid crystal display device as an inner side polarizing plate protective film located between a polarizer and a liquid crystal cell.
The cellulose acylate film is considered to have an effect of reducing moisture reaching the polarizer from the outside atmosphere, and from the viewpoint of effectively exhibiting such an effect, it should be included as a protective film for the viewing side polarizing plate. It is more preferable that it is included as an outer protective film for the viewing side polarizing plate.
Further, from the viewpoint of improving the adhesion with the polarizer, in any of the polarizing plates, the surface bonded to the polarizer directly or via an adhesive is preferably the surface B. In this regard, a more preferable aspect will be described later.

  Along with the cellulose acylate film, other film members can be used as a polarizing plate protective film. Other film members used in this case are not particularly limited, and various film members usually used as a polarizing plate protective film can be used.

  Moreover, as a polarizer, an iodine dyeing polyvinyl alcohol film can be used, for example. As such a film, for example, a film obtained by immersing and stretching a polyvinyl alcohol film in an iodine solution can be used. When using a polarizer obtained by immersing and stretching a polyvinyl alcohol film in an iodine solution, for example, the saponification surface of the cellulose acylate film can be directly bonded to at least one surface of the polarizer using an adhesive. . In the present invention and the present specification, the term “adhesive” is used to include an adhesive and a pressure-sensitive adhesive. As the adhesive, an aqueous solution of polyvinyl alcohol or polyvinyl acetal (for example, polyvinyl butyral), a latex of a vinyl polymer (for example, polybutyl acrylate), or an ultraviolet curable adhesive can be used. A particularly preferred adhesive is an aqueous solution of fully saponified polyvinyl alcohol.

The polarizing plate protective film is preferably bonded to the polarizer so that the transmission axis of the polarizer and the slow axis of the polarizing plate protective film are substantially parallel, orthogonal or 45 °. The slow axis can be measured by various known methods, for example, using a birefringence meter (KOBRADH, manufactured by Oji Scientific Instruments).
Here, substantially parallel, orthogonal or 45 ° means that the deviation between the direction of the main refractive index nx of the polarizing plate protective film and the direction of the transmission axis of the polarizing plate is within 5 °. It is preferable that the angle is within 1 °, preferably within 0.5 °. If the deviation is within 1 °, the polarization degree performance under the polarizing plate crossed Nicol is unlikely to deteriorate, and light leakage is not likely to occur.

  As described above, the surface B is a surface on which the urethane bond-containing compound is unevenly distributed. Using the surface B as a bonding surface with a polarizer, the cellulose acylate film is bonded directly to the polarizer or via an adhesive (preferably via an adhesive having a hydroxy group such as polyvinyl alcohol). It is preferable to produce a polarizing plate from the viewpoint of improving the adhesion between the polarizing plate protective film (the cellulose acylate film) and the polarizer. In this regard, the present inventor has an interaction between a urethane bond contained in the urethane bond-containing compound that is unevenly distributed on the surface B side and a partial structure (eg, a hydroxy group) having hydrogen bonding properties contained in a polarizer or an adhesive. Thus, it is presumed that the formation of hydrogen bonds brings about an improvement in adhesion. From this point, it is preferable to use the iodine-stained polyvinyl alcohol film as the polarizer.

(Multi-functionalization of polarizing plate)
The polarizing plate is an antireflection film for improving the visibility of a liquid crystal display device, a brightness enhancement film, a hard coat layer, a forward scattering layer, an antiglare (antiglare) layer, etc., without departing from the spirit of the present invention. It can also be used as a functionalized polarizing plate combined with an optical film having a functional layer. Details of these can be referred to the descriptions in paragraphs 0229 to 0242, paragraphs 0249 to 0250 and paragraphs 0086 to 0103 in JP 2012-215812 A, and the contents thereof are incorporated in the present specification. It is.

  As an example, a hard coat layer will be described below.

(Hard coat layer)
If desired, a hard coat layer can be provided on the cellulose acylate film. For example, the hard coat layer can be formed on the cellulose acylate film by applying the coating composition onto the cellulose acylate film and curing it. By adding fillers and additives to the hard coat layer, chemical performance such as mechanical, electrical and optical physical performance and water / oil repellency can be imparted to the hard coat layer. The thickness of the hard coat layer is preferably in the range of 0.1 to 6 μm, and more preferably in the range of 3 to 6 μm. By having a thin hard coat layer in such a range, it is possible to obtain a polarizing plate including a hard coat layer that has improved physical properties such as brittleness and curl suppression, reduced weight, and reduced manufacturing costs.

  An example of the coating composition for forming the hard coat layer contains a monomer or oligomer for matrix forming binder, a polymer and an organic solvent. A hard coat layer can be formed by curing the coating composition after coating. For curing, a crosslinking reaction or a polymerization reaction can be used. Details of these can be referred to the description in paragraphs 0088 to 0101 of JP2012-215812A, the contents of which are incorporated herein.

  The coating composition can be prepared, for example, by dissolving and / or dispersing the above-described components in an organic solvent. A coating composition suitable for forming the hard coat layer is a curable composition containing a (meth) acrylate compound. The (meth) acrylate compound includes an acrylic compound and a methacrylic compound.

[Liquid Crystal Display]
A liquid crystal display device according to one embodiment of the present invention includes at least one polarizing plate according to one embodiment of the present invention. Details of the liquid crystal display device can be referred to the descriptions in paragraphs 0251 to 0260 of JP2012-082235A, and the contents thereof are incorporated in this specification. The polarizing plate can be used as any polarizing plate of a viewing side polarizing plate and a backlight side polarizing plate. In one embodiment, it is preferable to use the polarizing plate as at least the viewing side polarizing plate.

  Although not illustrated, as another configuration, as a part of a circularly polarizing plate arranged as an antireflection application of a self-luminous element such as a reflective or transflective liquid crystal display device or organic EL (Electro Luminescence) The polarizing plate according to one embodiment of the present invention can also be used.

  In addition, since the cellulose acylate film according to one embodiment of the present invention can exert an effect of reducing the influence of moisture, it is not limited to a polarizing plate protective film, but is used for various applications where it is desirable to reduce the influence of moisture. It is also useful as a film.

The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.
All synthesized compounds were identified by using ¹ H-NMR (Nuclear Magnetic Resonance) (300 MHz) and infrared spectroscopy (IR).

[Examples of compound synthesis]
<Synthesis of Exemplified Compound A>
In a three-necked flask with a condenser (300 ml), 30.0 g of hexamethylene diisocyanate (manufactured by Wako Pure Chemical Industries), 59.9 g of 1,1,1,3,3,3-hexafluoro-2-propanol (manufactured by Wako Pure Chemical Industries) and After adding 150 g of tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd.) and stirring at room temperature under a nitrogen stream, 1 mg of bismuth catalyst (Neoto U-600 manufactured by Nitto Kasei) was added and the liquid temperature was raised to 50 ° C. Stir for 48 hours. At this time, the equivalent when the reaction of isocyanate (NCO) and alcohol (OH) was charged was 1. Thereafter, the reaction solution was allowed to cool to room temperature, and poured into 3 L of separately stirred water to precipitate the target solid. The precipitated solid was separated by filtration, and the obtained solid was dried under normal pressure (101.33 kPa) and an ambient temperature of 50 ° C. for 48 hours to obtain Illustrative Compound A solid.

<Synthesis of Exemplified Compounds B to H and Comparative Compounds I to K>
Exemplified compounds B to H and comparative compounds I to K were synthesized by the same synthesis method as that for Exemplified Compound A, except that the types of the raw material fluorine group-containing alcohol and isocyanate were changed. In addition, in the synthesis | combination of any compound, the equivalent at the time of reaction preparation of isocyanate and alcohol was made to become 1.

The structures of exemplary compounds A to H are as described above. Comparative compounds I to K are compounds having the following structures.
It was confirmed by ¹ H-NMR spectrum and IR spectrum that the product obtained by the synthesis was the target product.

[Film formation of cellulose acylate film]
<Preparation of cellulose acylate solution>
The following composition is put into a mixing tank, stirred to dissolve each component, further heated at a liquid temperature of 90 ° C. for about 10 minutes, and then sequentially filtered through a filter paper having an average pore size of 34 μm and a sintered metal filter having an average pore size of 10 μm. Then, a cellulose acylate solution I was prepared.

―――――――――――――――――――――――――――――――――――――
Composition of cellulose acylate solution I ――――――――――――――――――――――――――――――――――――――
Cellulose acylate (degree of substitution 2.88, number average molecular weight 163000)
100.0 parts by mass The compounds described in Table 1 10.0 parts by mass polycondensation ester plasticizer S3 3.0 parts by mass Methylene chloride 451.0 parts by mass Methanol 39.0 parts by mass ―――――――――――――――――――――――――――

Polycondensation ester plasticizer S3:
Adipic acid: ethanediol = 100: 100 (molar ratio) polycondensed ester compound (no end-capping, hydroxyl value 112 mgKOH / g, number average molecular weight: 1000)

<Preparation of matting agent dispersion>
Next, the following composition containing the cellulose acylate solution prepared by the above method was charged into a disperser to prepare a mat agent dispersion.
―――――――――――――――――――――――――――――――――――――
Composition of matting agent dispersion ―――――――――――――――――――――――――――――――――――――
-Matting agent (Aerosil (registered trademark) R972 manufactured by Nippon Aerosil Co., Ltd.) 0.2 parts by mass-Methylene chloride 72.4 parts by mass-Methanol 10.8 parts by mass-Cellulose acylate solution I 10.3 parts by mass ―――――――――――――――――――――――――――――――――

<Preparation of dope for film formation>
The cellulose acylate solution I was mixed in an amount of 100 parts by mass, and the matting agent dispersion was mixed with the cellulose acylate resin in an amount such that the matting agent fine particles were 0.20 parts by mass to prepare a dope for film formation.

<Casting>
The film-forming dope was cast using a band casting machine. The band was made of stainless steel (SUS; Steel Special Use Stainless).

<Drying>
The web (film) obtained by casting was peeled off from the band, and then dried for 20 minutes in a tenter device (temperature in the device: 100 ° C.) using a tenter device that holds and conveys both ends of the web with clips. .
Thereafter, the web was further dried by carrying it through a drying zone at a drying temperature of 120 ° C.
Thus, a cellulose acylate film having a thickness of 60 μm was obtained.

[Preparation of polarizing plate]
<Saponification treatment of polarizing plate protective film>
The cellulose acylate films of Examples and Comparative Examples were immersed in a 2.3 mol / L sodium hydroxide aqueous solution (liquid temperature 55 ° C.) for 3 minutes. It wash | cleaned in the room temperature water bath, and neutralized using 0.05 mol / L sulfuric acid at the liquid temperature of 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 saponification process was performed with respect to the cellulose acylate film.

<Production of polarizer>
A 75 μm-thick polyvinyl alcohol film (9X75RS manufactured by Kuraray Co., Ltd.) is continuously conveyed by a guide roll, immersed in a 30 ° C. water bath to swell 1.5 times, and stretched twice by stretching. After the magnification, it is immersed in a dyeing bath (30 ° C.) containing iodine and potassium iodide, dyeing treatment and stretching treatment to obtain a drawing magnification of 3 times, and then it is added with boric acid and potassium iodide. The film was subjected to crosslinking treatment in a bath (60 ° C.) and stretched to a draw ratio of 6.5 times and dried in an atmosphere at an atmosphere temperature of 50 ° C. for 5 minutes to obtain a polarizer having a thickness of 20 μm.

<Lamination of polarizer and polarizing plate protective film>
A polyvinyl alcohol-based adhesive (about 10 ml) was dropped onto the saponified cellulose acylate film. The surface of the cellulose acylate film on which the polyvinyl alcohol adhesive was dropped and the one side of the polarizer prepared above were bonded together to obtain a laminate. In addition, about the cellulose acylate film of an Example, polyvinyl alcohol adhesive is dripped with respect to the surface (surface B) where the peak intensity was higher in the measurement of the peak intensity ratio described later, and the surface to be bonded to the polarizer did.
Thereafter, the obtained laminate was placed in an oven with an atmospheric temperature of 50 ° C. in a state where a SUS plate having a length of 30 cm × width of 30 cm × thickness of 1 cm was placed on the surface of the cellulose acylate film and a load was applied. Heated for minutes. After removing the laminate from the oven, the SUS plate was removed.
Subsequently, the same cellulose cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Film Co., Ltd.) was subjected to the same saponification treatment, and each cellulose acylate film of the laminate produced above was attached using a polyvinyl alcohol-based adhesive. It was affixed to the surface of the polarizer opposite to the attached side.
At this time, the transmission axis of the polarizer and the slow axis of the obtained cellulose acylate film were arranged in parallel. Further, the transmission axis of the polarizer and the slow axis of the commercially available cellulose triacetate film were arranged so as to be orthogonal to each other.
Thus, each polarizing plate was produced. In addition, separately from preparation of a polarizing plate, the laminated body of a polarizer and each cellulose acylate film was produced by the said method, and it used as a sample of the adhesive evaluation mentioned later.

[Evaluation method]
<Peak intensity ratio PA / PB, concentration ratio FA / FB>
A film sample of 1 cm × 1 cm size was cut out from the cellulose acylate films of Examples and Comparative Examples, and the peak intensity ratio PA / PB and the concentration ratio FA / FB were determined by the method described above.
For measurement of the peak intensity ratio PA / PB, an IR apparatus (FT-IR Nicolet670 manufactured by Thermo Fisher) was used, and for measurement of the concentration ratio FA / FB, an XPS apparatus (Quantera SXM manufactured by ULVAC-PHI) was used. . Since the cellulose acylate films of the examples had different peak intensities on one surface and the other surface, the surface having a smaller peak intensity was designated as surface A, and the surface on the larger side was designated as surface B. PA was determined, and for these surface A and surface B, the concentration ratio FA / FB was determined.

<Evaluation of polarizing plate durability>
The polarizing plate durability test was performed as follows in a form in which the produced polarizing plate was attached to glass via an adhesive.
Two samples (about 5 cm × 5 cm) were prepared by attaching polarizing plates on glass so that the cellulose acylate films of Examples and Comparative Examples were on the air interface side. In the single plate orthogonal transmittance measurement, this sample was measured with the glass side facing the light source. The measurement is performed in the range of 380 nm to 780 nm using an automatic polarizing film measuring device VAP-7070 manufactured by JASCO Corporation, and the orthogonal transmittance at 410 nm, which is a wavelength at which the influence of the deterioration in the performance of the polarizer is prominent. The measured value was adopted. Two samples were measured, and the average value was defined as the single plate orthogonal transmittance of the polarizing plate.
The parallel transmittance was measured by the same method as in the case of the above-mentioned single-plate orthogonal transmittance measurement except that the produced sample was rotated by 90 °. Two samples were measured, and the average value was taken as the parallel transmittance of the polarizing plate.
From the values of the single plate orthogonal transmittance and the parallel transmittance measured above, the degree of polarization (degree of polarization before aging) was determined by the following formula.
Polarization degree (%) = [(single plate orthogonal transmittance−parallel transmittance) / (single plate orthogonal transmittance + parallel transmittance)] 1/2 × 100

Thereafter, in the same manner as described above, a sample in which the produced polarizing plate was attached to glass via an adhesive was prepared, and after being stored for 500 hours in an environment with an atmospheric temperature of 85 ° C. and a relative humidity of 85%, the same as above. The degree of polarization (degree of polarization after time) was determined by the method. In addition, the relative humidity in the environment without humidity control was in the range of 0 to 20%.
From the degree of polarization before and after aging, the amount of change in the degree of polarization was calculated according to the following formula.
Change in polarization degree (%) = [degree of polarization after time (%) − degree of polarization before time (%)]

The polarizing plate durability was evaluated based on the following criteria from the calculated amount of change in polarization degree. It can be determined that the smaller the amount of change in the degree of polarization obtained by the above method, the better the polarizing plate durability. Storage for 500 hours in an environment with an atmospheric temperature of 85 ° C. and a relative humidity of 85% is a severe storage condition, and if the evaluation result is B or more under this condition, it can be said that the polarizing plate has normally required durability. If the evaluation result is A or A + or higher, it is judged to have extremely excellent polarizing plate durability that can continue to exert its role as a polarizing plate even when used in various environments. Can do.
A +: Polarization degree change before and after aging is less than 0.05% A: Polarization degree change before and after aging is 0.05% or more and less than 2.0% B: Polarization degree change before and after aging is 2.0% or more Less than 3.0% C: The degree of polarization change before and after aging is 3.0% or more

<Moisture permeability>
The moisture permeability of the cellulose acylate films of Examples and Comparative Examples is the mass of water vapor passing through the sample in 24 hours in an atmosphere at a temperature of 40 ° C. and a relative humidity of 90% according to the moisture permeability test (cup method) of JIS Z0208. Was determined as a value converted to the mass of water vapor passing in 24 hours per 1 m ^{2 of} the sample area.

  The results are shown in Table 1.

  From the results shown in Table 1, it can be confirmed that the polarizing plates of the examples have extremely excellent polarizing plate durability. Moreover, the cellulose acylate film of the Example had a low moisture permeability as compared with the cellulose acylate film of the comparative example. The inventor speculates that this contributes to the improvement of the durability of the polarizing plate.

<Adhesion between polarizing plate protective film and polarizer>
About the polarizing plate of an Example and a comparative example, the adhesiveness of a polarizing plate protective film (cellulose acylate film) and a polarizer was evaluated with the following method using the laminated body produced above. The laminate was cut into a size of 200 mm in parallel with the stretching direction of the polarizer and 15 mm in the orthogonal direction, and cut with a cutter knife between the cellulose acylate films of the examples and comparative examples and the polarizer, and then laminated. The surface of the cellulose acylate film was bonded to a glass plate. Using the Tensilon universal testing machine RTG series (manufactured by A & D Co., Ltd.), the cellulose acylate film and the polarizer were peeled at a peeling speed of 3000 mm / min in the 90-degree direction, and the peel strength (unit: N ( Newton)) was measured. A similar test was performed on five laminates, and the arithmetic average value of the obtained peel strengths was used as an evaluation of adhesion. The larger the measured value, the greater the force required for peeling, that is, the better the adhesion. The measurement results are shown in Table 2.

[Production of liquid crystal display devices]
Peel off the polarizing plate on the viewing side of a commercially available liquid crystal television (BRAVIA J5000 from Sony Corporation), and make each polarizing plate produced in the above examples so that the polarizing plate protective film in each of the above examples is on the outer side. A liquid crystal display device was obtained by pasting via an adhesive.

  The present invention is useful in the technical field of liquid crystal display devices.

70 Casting film 85 Casting band 89 Casting die 120 Core layer dope 121 Skin layer A dope 122 Skin layer B dope 120a Core layer 121a Skin layer A
122a Skin layer B
150 Skin layer B (support layer) die 151 Core layer (base layer) die 152 Skin layer A (air surface layer) die

Claims (15)

A cellulose acylate film,
A compound containing one or more fluorine-containing groups selected from the group consisting of —CF ₃ , —CF ₂ H, and —CF ₂ — in one molecule and one or more urethane bonds in one molecule;
The peak intensity PA at a wave number of 1740 cm ⁻¹ determined by infrared absorption spectrum measurement on one surface A of the cellulose acylate film, and the wave number of 1740 cm determined by infrared absorption spectrum measurement on the other surface B of the cellulose acylate film. ^A cellulose acylate film in which the peak intensity ratio with respect to the peak intensity PB at ^-1 , PA / PB is in the range of 0 to 0.90. The concentration ratio FA / FB between the fluorine concentration FA determined on the surface A by photoelectron spectroscopy and the fluorine concentration FB determined on the surface B by photoelectron spectroscopy is in the range of 0 to 0.90. Cellulose acylate film. The cellulose acylate film according to claim 1 or 2, wherein the compound contains two or more fluorine-containing groups in one molecule. The cellulose acylate film according to claim 1, wherein the compound contains two or more urethane bonds in one molecule. The cellulose acylate film according to any one of claims 1 to 4, wherein the compound contains 2 to 6 urethane bonds in one molecule. The cellulose acylate film according to any one of claims 1 to 5, wherein the compound has a partial structure in which a urethane bond is directly connected to an aromatic ring. The cellulose acylate film according to claim 6, wherein the aromatic ring is a benzene ring. The cellulose acylate film according to claim 6 or 7, wherein in the partial structure, the urethane bond is directly connected to the aromatic ring by a nitrogen atom contained in the urethane bond. The cellulose acylate film according to any one of claims 6 to 8, wherein the compound has one or two of the partial structures in one molecule. The cellulose acylate film according to any one of claims 1 to 9, wherein the compound has a molecular weight of 200 or more and 2000 or less. The cellulose acylate film according to any one of claims 1 to 10, wherein the compound is contained in an amount of 0.1 to 50.0 parts by mass with respect to 100.0 parts by mass of the cellulose acylate. The polarizing plate containing the cellulose acylate film of any one of Claims 1-11, and a polarizer. The polarizing plate according to claim 12, wherein the polarizer is an iodine-stained polyvinyl alcohol film. A liquid crystal display device comprising the polarizing plate according to claim 13 and a liquid crystal cell. The liquid crystal display device according to claim 14, comprising the polarizing plate as at least a viewing-side polarizing plate.