KR101158379B1 - Cellulose acylate film, polarizing film and liquid crystal display - Google Patents

Abstract

(Problem) Cellulose acylate film with small optical anisotropy and small change in optical characteristics due to heat and humidity; Polarizing plate protective film having no surface failure and no change in performance in manufacturing a polarizing plate, and having excellent workability and durability; And a polarizing plate using the protective film in a liquid crystal display device, to provide a liquid crystal display device having a high display quality at a wide viewing angle.

(Solution means) The cellulose acylate film whose absolute value of the difference between Rth of 25 ° C and 60% RH is 25 nm or less, and the difference between Rth of 25 ° C and 10% RH and Rth of 25 ° C and 80% RH is 40 nm or less.

Cellulose acylate film, polarizing plate, liquid crystal display device

Description

Cellulose acylate film, polarizer and liquid crystal display {CELLULOSE ACYLATE FILM, POLARIZING FILM AND LIQUID CRYSTAL DISPLAY}

In FIG. 1, (A) is a schematic sectional drawing which shows the example which stuck the functional optical film to both surfaces on one side of the polarizing plate of this invention, and (B).

2 is a schematic view showing a liquid crystal display device using the polarizing plate of the present invention.

Explanation of symbols on the major symbols in the drawings

1a, 1b: protective film

2: polarizer

3: functional optical film

4: adhesion layer

11: upper polarizer

12: upper polarizer absorption axis

13: upper viewing angle enlarged film

14: direction of orientation of the upper optically anisotropic layer

15: upper electrode substrate of the liquid crystal cell

16: Upper substrate orientation control direction

17: liquid crystal molecules                 

18: lower electrode substrate of the liquid crystal cell

19: Lower substrate orientation control direction

20: lower viewing angle magnification film

21: direction of lower optically anisotropic layer orientation

22: lower polarizer

23: lower polarizer absorption axis

This invention relates to the cellulose acylate film used suitably for a polarizing plate, the polarizing plate using this film, and the liquid crystal display device provided with the polarizing plate.

Cellulose acylate film is widely used as a protective film of a polarizing plate for liquid crystal display device in view of having appropriate water vapor permeability and easy processing. On the other hand, however, there is a drawback that the change in retardation due to humidity is large. Since this causes problems such as light leakage in the long-term use of the polarizing plate, improvement is strongly demanded.

Conventionally, as a means of improving the humidity dependency of a cellulose acylate film, the method of (1) adding a low molecular weight compound with high hydrophobicity, and (2) the method of improving the hydrophobicity of cellulose acylate itself is proposed.

About said (1), the film with small humidity dependence of retardation value is disclosed by patent document 1 (Unexamined-Japanese-Patent No. 2001-114914). In addition, about (2), the patent document 2 (Unexamined-Japanese-Patent No. 8-231761) has the cellulose acylate whose substitution degree of the acyl group of 3 or more carbon atoms is 0.3 or more and 0.8 or less. Patent Publication No. 2003-170492) discloses a cellulose acylate film having an acetyl substitution degree of 1.4 or more and 2.85 or less and a total acyl substitution degree of 2.3 or more and 2.85 or less.

However, the method has a certain effect, but the improvement of the humidity is still insufficient because of the humidity dependence of the retardation.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2001-114914

[Patent Document 2] Japanese Patent Application Laid-Open No. 8-231761

[Patent Document 3] Japanese Unexamined Patent Publication No. 2003-170492

An object of the present invention is to provide a cellulose acylate film having a small optical anisotropy.

Another object of the present invention is to provide a cellulose acylate film having a small change in optical characteristics due to heat and humidity.

Still another object of the present invention is to provide a polarizing plate protective film which is excellent in processability and excellent in durability, without surface defects and performance changes in polarizing plate production.

Still another object of the present invention is to use a polarizing plate using a protective film having a small optical anisotropy and a small change in optical characteristics due to heat or humidity, in a liquid crystal display device, without causing problems such as light leakage and at a wide viewing angle. It is to provide a liquid crystal display device having high display quality.

As a result of careful examination by the present inventors, the humidity dependence of the retardation of a cellulose acylate film is mainly caused by the hydrogen bond formation of the water molecule and the carbonyl group in an acyl group, and the influence of the hydroxyl group in the cellulose acylate conventionally considered is small. I found that. Moreover, the present inventors found that two means using (ac) water absorption of a cellulose acylate film, and (B) using an acyl group which is difficult to hydrogen bond with water are effective as a means of solving the said subject.

On the other hand, hydrophobization of the substituent of a cellulose acylate is effective also in any of said (A) and (B), On the contrary, glass transition temperature (henceforth "Tg") of a cellulose acylate film falls by this and dimensional stability Is significantly worsened.

In order to solve this dilemma, the substitution degree of cellulose acetate is made high about (A), and the hydrophobization agent which hardly reduces Tg of cellulose acylate is combined, or (B), the carbon number of the acyl group in a cellulose acylate It is very effective to increase the ratio of hydrophobic groups to a small number of acyl groups and to increase the ratio of hydroxyl groups, thereby greatly reducing the retardation change due to humidity, and having excellent dimensional stability, low equilibrium moisture content, and low moisture permeability. The knowledge that a late film can be obtained was also acquired.

That is, according to this invention, the cellulose acylate film, polarizing plate, and liquid crystal display device of the following structure are provided, and the objective of this invention is achieved.

1. The cellulose acylate film characterized in that the absolute value of the difference between Rth of 25 ° C and 60% RH is 25 nm or less, and the absolute value of the difference between Rth of 25 ° C and 10% RH and Rth of 25 ° C and 80% RH is 40 nm or less. .

2. A cellulose acylate film, wherein the Re of 25 ° C. 60% RH is 0 nm or more and 20 nm or less, and the absolute value of the difference between Re of 25 ° C. 10% RH and Re of 25 ° C. 80% RH is 20 nm or less. .

3. The cellulose acylate film obtained by the manufacturing method which has a process which casts the cellulose acylate solution containing a cellulose acelate and a solvent on a support body, and removes the film obtained by casting | flow_spread from a support body,

I / O ratio of the residual solvent in the film obtained by casting | flow_spread is 0.65 or more and 4 or less at the time of removing this film from a support body,

A cellulose acylate film, wherein the cellulose acylate film has at least one hydrogen bondable hydrogen donor group and contains a compound having an octanol-water partition coefficient of 2 or more and 12 or less.

4. At least 1 sort (s) of the compound represented by following General formula (I) is contained, The cellulose acylate film of said 3 characterized by the above-mentioned.

General formula (Ⅰ)                     

[Formula 1]

In General Formula (I), R ¹ and R ² each independently represent an alkyl group which may have a substituent or an aryl group which may have a substituent.

5. At least 1 sort (s) of the compound represented by following General formula (II) is contained, The cellulose acylate film in any one of said 3 or 4 characterized by the above-mentioned.

General formula (Ⅱ)

[Formula 2]

In General Formula (II), X ² represents B, CR (R represents a hydrogen atom or a substituent), or N. R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ²¹ , R ²² , R ²³ , R ²⁴ , R ²⁵ , R ³¹ , R ³² , R ³³ , R ³⁴ to R ³⁵ represent a hydrogen atom or a substituent Indicates)

6. At least 1 alkylphthalyl alkylglycolate type compound is contained, The cellulose acylate film in any one of said 3-5 characterized by the above-mentioned.

7. At least 1 sort (s) of polyhydric alcohol ester of an aliphatic polyhydric alcohol and 1 or more types of monocarboxylic acid, The cellulose acylate film in any one of said 3-6 characterized by the above-mentioned.

8. The ratio of the phosphate ester compound with respect to cellulose acylate is 5 mass% or less, The cellulose acylate film in any one of said 3-7 characterized by the above-mentioned.

9. Cellulose acylate is cellulose acylate whose substitution degree of acetyl group is 2.80 or more and 3.00 or less, The cellulose acylate film in any one of said 3-8 characterized by the above-mentioned.

10. Substitution degree of acyl group is 1 or more and 2.9 or less, and substitution degree of acetyl group is less than 2.5, The cellulose acylate film in any one of said 3-8 characterized by the above-mentioned.

11. Substitution degree of acyl group is 1 or more and 2.6 or less, substitution degree of acetyl group is 1.4 and average carbon number of acyl group is 2.4 or more and 5 or less, The cellulose acylate film of said 10 characterized by the above-mentioned.

12. The solvent contains methylene chloride and alcohol, and

When the sum total of methylene chloride and alcohol is 100 mass%, the ratio of alcohol is 10 mass% or more and 40 mass% or less, The cellulose acylate film in any one of said 3-11 characterized by the above-mentioned.

13. It has physical property of said 1 or 2, The cellulose acylate film in any one of said 3-12 characterized by the above-mentioned.

14. Water vapor transmission rate when it is left to stand in 25 degreeC 90% RH atmosphere for 24 hours is 20 g / m <2> or more and 250g / m <2> or less, The cellulose acylate film in any one of said 1-13 characterized by the above-mentioned.

15. Equilibrium moisture content in 25 degreeC 80% RH is 6 mass% or less, The cellulose acylate film in any one of said 1-14 characterized by the above-mentioned.

16. The cellulose acylate film according to any one of 1 to 15 above, wherein the rate of dimensional change at 90 ° C for 24 hours is -0.5% or more and 0.5% or less.

17. The elastic modulus of any one of conveyance direction or width direction is 1.0 kPa or more and 6.0 kPa or less, The cellulose acylate film in any one of said 1-16 characterized by the above-mentioned.

18. A polarizing plate in which protective films are bonded to both sides of a polarizer, wherein at least one of the protective films is a cellulose acylate film according to any one of the above 1 to 17.

19. The polarizing plate of said 18 characterized by providing the adhesive layer in the polarizing plate.

20. The polarizing plate according to the above 18 or 19, wherein an antiglare layer is formed on the air side protective film.

21. The polarizing plate in any one of said 18-20 which has an antireflection film layer.

22. It has a retardation film layer or (lambda) / 4 plate, The polarizing plate in any one of said 18-21 characterized by the above-mentioned.

23. It has a viewing angle expansion film layer, The polarizing plate in any one of said 18-22 characterized by the above-mentioned.

24. A polarizing plate according to any one of claims 18 to 22, which has a luminance enhancing film layer.

25. The liquid crystal display device which consists of a liquid crystal cell and two polarizing plates arrange | positioned at both sides, and at least 1 polarizing plate is a polarizing plate in any one of said 18-24.

26. The liquid crystal display device according to 25, wherein the liquid crystal display device is in VA mode.

27. The liquid crystal display device according to 25, wherein the liquid crystal display device is in an IPS mode.

MEANS TO SOLVE THE PROBLEM This inventor succeeded in manufacturing the cellulose acylate film and polarizing plate which are small in the change of the optical compensation ability by humidity, and excellent in durability.                     

The polarizing plate having the optical compensation function can be particularly advantageously used for VA (vertically aligned) type and IPS (in-phase switching) type liquid crystal display device.

Best Mode for Carrying Out the Invention

[Cellulose acylate]

First, the cellulose acylate of the present invention will be described.

The substitution degree of a cellulose acylate means the ratio in which the three hydroxyl groups which exist in the structural unit (glucose couple | bonded with (beta) 1 -4 glycosidic bond) of a cellulose are acylated. The degree of substitution can be calculated by measuring the amount of bound fatty acid per constituent unit mass of cellulose. The measuring method is carried out in accordance with ASTM-D817-91.

The cellulose acylate of the present invention balances the hydrophobicity of the acyl group with the hydrophilicity of the hydroxyl group by appropriately balancing both the humidity dependence of the retardation and the dimensional stability. In other words, if the alkyl chain in the acyl group is too short on average or the hydroxyl group ratio is too high, the humidity dependency of the retardation increases. In addition, if the alkyl chain in the acyl group is too long on average or the hydroxyl group ratio is too high, the Tg is lowered and the dimensional stability deteriorates.

Therefore, it is preferable that the cellulose acylate of this invention is 2.80 or more and 3.0 or less of substitution degree (acetylation degree) of an acetyl group, and does not have an acyl group of 3 or more carbon atoms. The degree of acetylation is more preferably 2.85 or more and 3.0 or less, and most preferably 2.90 or more and 3.0 or less.

Moreover, as for the preferable cellulose acylate of another one of this invention, the substitution degree (acylation degree) of an acyl group is 1 or more and 2.9 or less, More preferably, it is 1 or more and 2.6 or less, More preferably, 1.7 or more and 2.5 or less , 1.8 or more and 2.2 or less are most preferable. Moreover, 2 or more and 7 or less are preferable, as for the average carbon number of an acyl group, 2.05 or more and 5 or less are more preferable, 2.4 or more and 5 or less are more preferable, 2.6 or more and 4 or less are most preferable.

As the acyl group, an acyl group having 2 to 6 carbon atoms is preferable, and an acetyl group, propionyl group and butyryl group are particularly preferable. In addition, when the cellulose acylate film of the present invention has an acetyl group and other acyl groups, the degree of substitution of the acetyl group is preferably less than 2.5, more preferably less than 1.9, still more preferably less than 1.4, and most preferably less than 1.1. desirable. In this invention, it is especially preferable that the substitution degree of an acyl group is 1 or more and 2.6 or less, the substitution degree of an acetyl group is 1.4 and the average carbon number of an acyl group is 2.4 or more and 5 or less.

It is preferable that the cellulose acylate of this invention has a mass average polymerization degree of 350-800, and it is more preferable to have a mass average polymerization degree of 370-600. The cellulose acylate of the present invention preferably has a number average molecular weight of 70000 to 230000, more preferably has a number average molecular weight of 75000 to 230000, and most preferably has a number average molecular weight of 78000 to 120000.

The cellulose acylate of the present invention can be synthesized using an acid anhydride or an 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 the reaction solvent. As the catalyst, a protic catalyst such as sulfuric acid is used. When the acylating agent is an acid chloride, a basic compound is used as a catalyst. In the most common synthetic methods in the industry, cellulose is esterified with an organic acid (acetic acid, propionic acid, butyric acid) corresponding to an acetyl group and other acyl groups or a mixed organic acid component containing these acid anhydrides (acetic anhydride, propionic anhydride, butyric anhydride). To synthesize a cellulose ester. In this method, cellulose, such as cotton linter and wood pulp, is often esterified using an organic acid component mixture in the presence of sulfuric acid catalyst after activation treatment with an organic acid such as acetic acid. The organic acid anhydride component is generally used in excess of the amount of hydroxyl groups present in the cellulose. In this esterification process, hydrolysis reaction (depolymerization reaction) of a cellulose main chain ((beta) 1 -4 glycoside bond) advances in addition to esterification reaction. As the hydrolysis reaction of the main chain proceeds, the degree of polymerization of the cellulose ester is lowered and the physical properties of the cellulose ester film to be produced are lowered. For this reason, it is preferable to determine reaction conditions, such as reaction temperature, in consideration of the polymerization degree and molecular weight of the cellulose ester obtained.

In order to obtain a cellulose ester with a high degree of polymerization (high molecular weight), it is important to adjust the maximum temperature in the esterification step to 50 ° C or lower. The maximum temperature is preferably adjusted to 35 to 50 ° C, more preferably 37 to 47 ° C. If reaction temperature is less than 35 degreeC, esterification reaction may not progress smoothly. When reaction temperature exceeds 50 degreeC, the polymerization degree of a cellulose ester will fall easily. When the reaction is stopped while controlling the temperature rise after the esterification reaction, the decrease in the degree of polymerization can be further suppressed, and a cellulose ester having a high degree of polymerization can be synthesized. That is, when the reaction terminator (for example, water and acetic acid) is added after the completion of the reaction, the excess acid anhydride that is not involved in the esterification reaction is hydrolyzed to produce the corresponding organic acid by addition. This hydrolysis reaction is accompanied by severe exotherm, and the temperature in the reaction apparatus is raised. If the rate of addition of the reaction terminator is large, it generates heat rapidly beyond the cooling capacity of the reactor. For this reason, the hydrolysis reaction of a cellulose main chain advances remarkably and the polymerization degree of the cellulose ester obtained falls. In addition, part of the catalyst is bound to cellulose during the esterification reaction, and most of it is dissociated from the cellulose during addition of the reaction terminator. However, if the rate of addition of the reaction terminator is large, there is no sufficient reaction time because the catalyst dissociates, and part of the catalyst remains bound to cellulose. The cellulose ester to which the strong acid catalyst couple | bonds is very bad, and it is easy to decompose | disassemble by the heat etc. at the time of drying of a product, and a polymerization degree falls. For these reasons, after the esterification reaction, it is preferable to add a reaction terminating agent over a time period of preferably 4 minutes or more, more preferably 4 to 30 minutes, to stop the reaction. When the addition time of the reaction terminator is more than 30 minutes, industrial productivity is lowered. As a reaction terminator, water or an alcohol which decomposes an acid anhydride is generally used. In the present invention, however, a triester having low solubility in various organic solvents is not precipitated. Thus, a mixture of water and an organic acid is preferably used as the reaction terminator. When the esterification reaction is carried out under the above conditions, a high molecular weight cellulose ester having a mass average degree of polymerization of 500 or more can be easily synthesized.

Next, a hydrophobization agent having at least one hydrogen-bonded hydrogen donor group used in the present invention and an octanol-water partition coefficient (hereinafter logP) of 2 or more and 12 or less will be described.

As the hydrophobizing agent, a hydrophobic compound is preferred because it has a high water content lowering effect and a small Tg decrease. However, if the hydrophobicity is too high, on the contrary, the compatibility with cellulose acylate is too bad, and problems such as bleed-out occur.

The compound having a hydrogen bondable hydrogen donor group is preferable in view of the above low plasticity, water content lowering effect, and trade-off of prevention of bridging. As for logP which is a measure of the hydrophobicity of a hydrophobization agent, 2 or more and 12 or less are preferable, 2.5 or more and 11 or less are preferable, and 3 or more and 10 or less are most preferable. As the hydrogen bondable hydrogen donor group, functional groups such as -OH group and -NH group are particularly preferable.

As for the molecular weight of the hydrophobization agent of this invention, 250 or more and 2000 or less are preferable. Moreover, as for a boiling point, 260 degreeC or more is preferable. The boiling point can be measured using a commercially available measuring apparatus (for example, TG / DTA100, manufactured by Seiko Electronics Co., Ltd.).

As for the hydrophobization agent of this invention, 0.01-30 mass parts, Preferably 0.5-25 mass parts is used with respect to 100 mass parts of cellulose esters. The addition method of the hydrophobization agent of this invention can be added to dope, after melt | dissolving in the organic solvent of alcohol, methylene chloride, and dioxolane, or it can also be added in dope composition directly.

Although various compounds can be used as a hydrophobization agent which reduces water content without reducing the elasticity modulus and Tg of this invention, the compound represented by the following general formula (I) and (II) can be used especially preferably.

General formula (Ⅰ)

(3)

In General Formula (I), R ¹ and R ² each independently represent an alkyl group which may have a substituent or an aryl group which may have a substituent.

General formula (Ⅱ)

[Formula 4]

In General Formula (II), X ² represents B, CR (R represents a hydrogen atom or a substituent) or N. R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ²¹ , R ²² , R ²³ , R ²⁴ , R ²⁵ , R ³¹ , R ³² , R ³³ , R ³⁴ to R ³⁵ represent a hydrogen atom or a substituent Indicates.

Next, the compound of general formula (I) is demonstrated in detail.

In the general formula (I), it is particularly preferable that the total number of carbon atoms of R ¹ and R ² is 10 or more.

As a substituent of R <^1> and R <^2> , a fluorine atom, an alkyl group, an aryl group, an alkoxy group, a sulfone group, and a sulfonamide group is preferable, and an alkyl group, an aryl group, an alkoxy group, a sulfone group, and a sulfonamide group are especially preferable.

In addition, the alkyl group may be linear, branched or cyclic, preferably having 1 to 25 carbon atoms, more preferably 6 to 25, and having 6 to 20 (eg, methyl, ethyl, propyl, isopropyl, butyl, Isobutyl, t-butyl, amyl, isoamyl, t-amyl, hexyl, cyclohexyl, heptyl, octyl, bicyclooctyl, nonyl, adamantyl, decyl, t-octyl, undecyl, dodecyl, tridecyl, Tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, didecyl) are particularly preferred.

The aryl group is preferably 6 to 30 carbon atoms, particularly preferably 6 to 24 carbon atoms (e.g., phenyl, biphenyl, teruphenyl, naphthyl, binaphthyl, triphenylphenyl).                     

Although the preferable example of a compound represented by general formula (I) is shown below, this invention is not limited to these specific examples.

[Chemical Formula 5]

[Formula 6]

Next, the compound of general formula (II) is demonstrated in detail.

X represents B, C-R (R represents a hydrogen atom or a substituent), N, P or P = O. X is preferably B, CR (R is preferably an aryl group, a substituted or unsubstituted amino group, alkoxy group, aryloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, acylamino group, alkoxycar Carbonylamino group, aryloxycarbonylamino group, sulfonylamino group, hydroxy group, mercapto group, halogen atom (e.g., fluorine atom, chlorine atom, bromine atom, iodine atom), carboxyl group, more preferably aryl group, alkoxy group, aryl Oxy group, a hydroxy group, a halogen atom, more preferably an alkoxy group, a hydroxy group, particularly preferably a hydroxy group), N, P = O, more preferably CR, N, and particularly preferably CR. . The substituent T mentioned later can be applied as a substituent.

R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ²¹ , R ²² , R ²³ , R ²⁴ , R ²⁵ , R ³¹ , R ³² , R ³³ , R ³⁴ and R ³⁵ are each independently a hydrogen atom Or a substituent. The substituent T mentioned later can be applied as a substituent. R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ²¹ , R ²² , R ²³ , R ²⁴ , R ²⁵ , R ³¹ , R ³² , R ³³ , R ³⁴ and R ³⁵ are preferably alkyl groups, Alkenyl group, alkynyl group, aryl group, substituted or unsubstituted amino group, alkoxy group, aryloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group , Sulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio group, arylthio group, sulfonyl group, sulfinyl group, ureide group, phosphate amide group, hydroxy group, mercapto group, halogen atom (e.g., fluorine atom, chlorine atom) , Bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably 1 to 30 carbon atoms, more preferably 1-12, and heteroatoms include nitrogen atom, oxygen atom, sulfur atom, Examples thereof include imidazolyl, pyridyl, quinolyl, furyl, piperidyl, morpholino, benzooxazolyl, benzimidazolyl, benzthiazolyl), and silyl groups, more preferably. Is an alkyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, and more preferably an alkyl group, an aryl group or an alkoxy group.

These substituents may be substituted again. In addition, when there are two or more substituents, they may be same or different. In addition, when possible, they may be connected to form a ring.

The substituent T mentioned above is demonstrated below. The substituent T is, for example, an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms, for example, methyl, ethyl, iso-propyl, tert-butyl, n-octyl). , n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl and the like), alkenyl group (preferably carbon 2 to 20, more preferably carbon 2 to 12, particularly preferably carbon number) 2-8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), alkynyl group (preferably C2-C20, more preferably C2-C12, especially preferably C2-C8, for example, propargyl, 3-pentenyl, etc. are mentioned, Aryl group (preferably C6-C30, More preferably, C6-C20, Especially preferably, C6-C12 , For example, phenyl, p-methylphenyl, naphthyl, and the like), substituted or misleading Amino group (preferably 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, for example amino, methylamino, dimethylamino, diethylamino, dibenzylamino, etc.) Alkoxy group (preferably 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methoxy, ethoxy, butoxy, etc.), aryl Oxy group (preferably C6-C20, more preferably C6-C16, especially preferably C6-C12, for example, phenyloxy, 2-naphthyloxy, etc.), acyl group (preferably Preferably it is C1-C20, More preferably, it is C1-C16, Especially preferably, it is C1-C12, For example, acetyl, benzoyl, formyl, pivaloyl, etc. are mentioned, The alkoxycarbonyl group (preferably 2-20 carbon atoms, more preferable Preferably it is C2-C16, Especially preferably, it is C2-C12, For example, methoxycarbonyl, ethoxycarbonyl, etc. are mentioned, An aryloxycarbonyl group (preferably C7-20, More preferably, 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, for example, phenyloxycarbonyl and the like, and an acyloxy group (preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms), particularly preferred. Preferably it is C2-C10, For example, acetoxy, benzoyloxy etc. are mentioned, Acylamino group (preferably C2-C20, More preferably, it is C2-C16, Especially preferably, it is C2-C10 For example, acetylamine, benzoylamino, etc.), an alkoxycarbonylamino group (preferably C2-C20, More preferably, it is C2-C16, Especially preferably, it is C2-C12, For example, methoxy And aryloxycarbonylamino groups (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms), for example, phenyloxycarbonylamino and the like. The sulfonylamino group (preferably C1-C20, More preferably, it is C1-C16, Especially preferably, it is C1-C12, For example, methanesulfonylamino, benzenesulfonylamino, etc. are mentioned. Sulfamoyl group (preferably 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms, for example, sulfamoyl, methyl sulfamoyl, dimethyl sulfamoyl, phenyl sulfamoyl, etc.). Carbamoyl group (preferably C1-C20, More preferably, it is C1-C16, Especially preferably, it is C1-C12, For example, carbamoyl, methyl carbamoyl, diethylcar Bar Mole, Phenylcarbamoyl, etc.), alkylthio group (preferably C1-C20, More preferably, it is C1-C16, Especially preferably, it is C1-C12, For example, methylthio, ethylthio, etc. are mentioned. Arylthio group (preferably 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, for example, phenylthio, etc.), sulfonyl group (preferably Preferably it is C1-C20, More preferably, it is C1-C16, Especially preferably, it is C1-C12, For example, mesyl, tosyl, etc. are mentioned, A sulfinyl group (Preferably C1-C20, More preferable) Preferably it is C1-C16, Especially preferably, it is C1-C12, For example, methane sulfinyl, benzene sulfinyl, etc. are mentioned, A ureide group (Preferably C1-C20, More preferably, C1-C1) To 16, particularly preferably 1 to 1 carbon atoms 2, for example, ureide, methyl ureide, phenyl ureide, and the like, a phosphate amide group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms). And diethyl phosphate amide, phenyl phosphate amide, etc.), hydroxy group, mercapto group, halogen atom (e.g., fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro Groups, hydroxamic acid groups, sulfino groups, hydrazino groups, imino groups, heterocyclic groups (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and hetero atoms such as nitrogen atom, oxygen atom, sulfur atom, Specifically, for example, imidazolyl, pyridyl, quinolyl, furyl, piperidyl, morpholino, benzooxazolyl, benzimidazolyl, benzthiazolyl, etc.), silyl group (preferably carbon number) 3-40, more preferable Crabs, and the like may be mentioned, and the surface of 3 to 30 carbon atoms, particularly preferably having a carbon number of 3 to 24, for example, trimethylsilyl, triphenylsilyl). These substituents may be substituted again. In addition, when there are two or more substituents, they may be same or different. Also, where possible, they may be linked to each other to form a ring.

Although the specific example is given and demonstrated in detail about the compound represented by general formula (II) below, this invention is not limited at all by the following specific examples.                     

[Formula 7]

[Formula 8]

As the hydrophobing agent (a compound having a hydrogen bondable hydrogen donor group and having a logP of 2 or more and 12 or less), an aliphatic polyhydric alcohol ester or an alkylphthalyl alkylglycolate is also preferable.

Next, the aliphatic polyhydric alcohol ester used for this invention is demonstrated in detail. The aliphatic polyhydric alcohol ester of the present invention is an ester of a divalent or higher aliphatic polyhydric alcohol and at least one monocarboxylic acid.

(Aliphatic polyhydric alcohol)                     

The aliphatic polyhydric alcohol used for this invention is bivalent or more alcohol, and is represented by following General formula (III).

General formula (III); R1- (OH) n

R1 is an n-valent aliphatic organic group, n is a positive integer of 2 or more, and an OH group represents an alcoholic hydroxyl group.

Examples of the n-valent aliphatic organic group include an alkylene group (eg, methylene group, ethylene group, trimethylene group, tetramethylene group, etc.), an alkenylene group (eg, ethenylene group, etc.), an alkynylene group (eg, ethynylene group, etc.), cyclo Alkylene group (for example, 1, 4- cyclohexanediyl group etc.) and an alkanetriyl group (for example, 1,2, 3- propane triyl group etc.) are mentioned. n-valent aliphatic organic groups include those having a substituent (for example, a hydroxy group, an alkyl group, a halogen atom, etc.).

As for n, 2-20 are preferable. Examples of preferred polyhydric alcohols include, for example, adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene Glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-heptanediol, 1,6-hexanediol, hexane Triol, garactitol, mannitol, 3-methylpentane-1,3,5-triol, vinacol, sorbitol, trimethylolpropane, trimethylolethane, xylitol and the like. In particular, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, and xylitol are preferable.

(Monocarboxylic acid)

As monocarboxylic acid in the polyhydric alcohol ester of this invention, a well-known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid, etc. can be used. When alicyclic monocarboxylic acid and aromatic monocarboxylic acid are used, it is preferable at the point which improves moisture permeability and retention.

Although the following are mentioned as an example of a preferable monocarboxylic acid, This invention is not limited to this.

As aliphatic monocarboxylic acid, the fatty acid which has a C1-C32 linear or branched chain can be used preferably. As for carbon number, it is more preferable that it is 1-20, and it is especially preferable that it is 1-10. It is preferable to contain acetic acid because compatibility with cellulose ester increases, and it is also preferable to mix acetic acid and another monocarboxylic acid.

Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, gylic acid, caproic acid, enanthic acid, caprylic acid, peralgonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecyl acid, lauric acid , Tridecyl acid, myristic acid, pentadecyl acid, palmitic acid, heptadecyl acid, stearic acid, nonadecanoic acid, arginic acid, behenic acid, lignocerinic acid, cellotic acid, heptaconic acid, montanic acid, meric acid, And unsaturated fatty acids such as saturated fatty acids such as lacxel acid, undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid, and arachidonic acid. These may further have a substituent.

Examples of preferred aliphatic monocarboxylic acids include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, or derivatives thereof.

As an example of a preferable aromatic monocarboxylic acid, the thing which introduce | transduced the alkyl group into the benzene ring of benzoic acid, such as benzoic acid and toluic acid, and the benzene ring, such as biphenyl carboxylic acid, naphthaline carboxylic acid, tetrain carboxylic acid, Aromatic monocarboxylic acid which has two or more, or these derivatives is mentioned. Especially benzoic acid is preferable.

(Polyhydric alcohol ester)

Although the molecular weight of the polyhydric alcohol ester used for this invention does not have a restriction | limiting in particular, It is preferable that it is 300-1500, and it is more preferable that it is 350-750. The larger one is preferable in terms of retention, and the smaller one is preferable in terms of moisture permeability and compatibility with cellulose esters.

The carboxylic acid in the polyhydric alcohol ester of this invention may be one type, or two or more types may be mixed. In addition, all the OH groups in the polyhydric alcohol may be esterified, and some may be left in the state of the OH group. It is preferable to have three or more aromatic rings or cycloalkyl rings in a molecule.

Examples of the polyhydric alcohol ester used in the present invention are shown below.                     

[Chemical Formula 9]

[Formula 10]

[Formula 11]

[Chemical Formula 12]

Next, the alkylphthalyl alkylglycolate which is preferably used in the present invention will be described.

Alkyl of alkylphthalyl alkylglycolate is an alkyl group having 2 to 8 carbon atoms. Alkylphthalyl alkylglycolates include ethylphthalylethylglycolate, propylphthalylpropylglycolate, butylphthalylbutylglycolate, octylphthalyloctylglycolate, methylphthalylethylglycolate, ethylphthalylmethylglycolate, Ethylphthalylpropylglycolate, propylphthalylethylglycolate, methylphthalylpropylglycolate, methylphthalylbutylglycolate, ethylphthalylbutylglycolate, butylphthalylmethylglycolate, butylphthalylethylglycolate, Propylphthalyl butylglycolate, butylphthalylpropylglycolate, methylphthalyloctylglycolate, ethylphthalyloctylglycolate, octylphthalylmethylglycolate, octylphthalylethylglycolate, and the like. Methylglycolate, ethylphthalylethylglycolate, propylphthalylpropylglycolate, Tilpeu talril butyl glycolate, octyl tilpeu talril octyl glycolate and acrylate are preferable, and particularly preferably used are ethyl program talril ethyl glycolate.

The compound, polyhydric alcohol ester, and alkylphthalyl alkylglycolate represented by general formula (I)-(II) can be used individually or in mixture of 2 or more types.

[Production of Cellulose Acylate Film]

It is preferable to manufacture the cellulose acylate film of this invention by the solvent cast method. In the solvent cast method, a film is manufactured using the solution (dope) which melt | dissolved cellulose acylate in the organic solvent.

The organic solvent preferably contains a solvent selected from ethers having 3 to 12 carbon atoms, ketones having 3 to 12 carbon atoms, esters having 3 to 12 carbon atoms, and halogenated hydrocarbons having 1 to 6 carbon atoms. .

Ethers, ketones and esters may have a cyclic structure. Compounds having two or more of functional groups of ethers, ketones and esters (ie, -O-, -CO- and -COO-) can also be used as the organic solvent. The organic solvent may have other functional groups such as alcoholic hydroxyl groups. In the case of the organic solvent which has two or more types of functional groups, it is preferable that the carbon atom number exists in the preferable carbon atom number range mentioned above among the solvent which has any one functional group.

Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phentol It contains.

Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclohexane and methylcyclohexanone.

Examples of esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate.

Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol.

The number of carbon atoms of the halogenated hydrocarbon is preferably 1 or 2, most preferably 1. The halogen of the halogenated hydrocarbon is preferably chlorine. It is preferable that the ratio which the hydrogen atom of a halogenated hydrocarbon is substituted by halogen is 25-75 mol%, It is more preferable that it is 30-70 mol%, It is more preferable that it is 35-65 mol%, It is 40-60 mol% Most preferred. Methylene chloride is a representative halogenated hydrocarbon.

The organic solvent of the present invention is preferably used by mixing methylene chloride and alcohol, the ratio of alcohol to methylene chloride is preferably 1% by mass or more and 50% or less, preferably 10% by mass or more and 40% by mass or less, 12 mass% or more and 30 mass% or less are the most preferable. As alcohol, methanol, ethanol, n-butanol is preferable, and two or more types of alcohol can also be mixed and used.

A cellulose acylate solution can be prepared by the general method which consists of processing at the temperature (normal temperature or high temperature) 0 degreeC or more. The solution can be prepared using a method and apparatus for preparing dope in a conventional solvent cast method.

The amount of cellulose acylate is adjusted so as to contain 10 to 40 mass% in the solution obtained. The amount of cellulose acylate is more preferably 10 to 30% by mass. In an organic solvent (main solvent), you may add the arbitrary additives mentioned later.

A solution can be prepared by stirring a cellulose acylate and an organic solvent at normal temperature (0-40 degreeC). The high concentration solution may be stirred under pressurized and heated conditions. Specifically, the cellulose acylate and the organic solvent are placed in a pressurized container and sealed, and the mixture is stirred while heating to a temperature not lower than the boiling point at normal temperature of the solvent and not boiling.

Heating temperature is 40 degreeC or more normally, Preferably it is 60-200 degreeC, More preferably, it is 80-110 degreeC.

Each component may be mixed beforehand into a container. It may also be added to the container sequentially. The vessel needs to be configured to be able to stir. The vessel can be pressurized by injecting an inert gas such as nitrogen gas. It is also possible to use an increase in the vapor pressure of the solvent by heating. Or after sealing a container, each component can also be added under pressure.

When heating, it is preferable to heat from the exterior of a container. For example, a jacket type heating device can be used. Moreover, the whole container can also be heated by installing a plate heater outside the container, piping, and circulating a liquid.

It is preferable to provide a stirring blade inside a container and to stir using this. The stirring vane is preferably of a length reaching the vicinity of the wall of the vessel. In order to update the liquid film of a container wall, it is preferable to provide a scraping blade at the end of the stirring blade.

Instruments can also be provided with instruments such as pressure gauges and thermometers. Each component is dissolved in a solvent in a container. The prepared dope is taken out of the container after cooling or taken out, and then cooled using a heat exchanger or the like.

A solution can also be prepared by a cooling solution method. In the cooling dissolution method, the cellulose acylate can be dissolved in an organic solvent which is difficult to dissolve by the usual dissolution method. Moreover, even if it is a solvent which can melt | dissolve a cellulose acylate by a normal dissolution method, there exists an effect that a uniform solution can be obtained quickly by a cooling dissolution method.

In the cooling solution method, the cellulose acylate is slowly added in an organic solvent at room temperature at first.

It is preferable to adjust the amount of cellulose acylate to contain 10-40 mass% in this mixture. The amount of cellulose acylate is more preferably 10 to 30% by mass. Moreover, you may add arbitrary additives mentioned later in a mixture.

The mixture is then cooled to -100 to -10 ° C (preferably -80 to -10 ° C, more preferably -50 to -20 ° C, most preferably -50 to -30 ° C). Cooling can be performed, for example, in a dry ice methanol bath (-75 ° C) or a cooled diethylene glycol solution (-30 to -20 ° C). The mixture of cellulose acylate and an organic solvent solidifies by cooling.

The cooling rate is preferably 4 ° C / minute or more, more preferably 8 ° C / minute or more, and most preferably 12 ° C / minute or more. The faster the cooling rate is, the better, but 10000 ° C / sec is the theoretical upper limit, 1000 ° C / sec is the technical upper limit, and 100 ° C / sec is the practical upper limit. The cooling rate is a value obtained by dividing the difference between the temperature at the start of cooling and the final cooling temperature by the time from when the cooling is started until the final cooling temperature is reached.

Moreover, when this is heated to 0-200 degreeC (preferably 0-150 degreeC, more preferably 0-120 degreeC, most preferably 0-50 degreeC), a cellulose acylate will melt | dissolve in an organic solvent. An elevated temperature may be left only to room temperature, and may be heated in a warm bath.                     

The heating rate is preferably 4 ° C / minute or more, more preferably 8 ° C / minute or more, and most preferably 12 ° C / minute or more. The higher the heating rate is, the better, but 10000 ° C / sec is the theoretical upper limit, 1000 ° C / sec is the technical upper limit, and 100 ° C / sec is the practical upper limit. In addition, the heating rate is a value obtained by dividing the difference between the temperature at the start of heating and the final heating temperature by the time from the start of heating until the final heating temperature is reached.

A homogeneous solution is obtained as mentioned above. Moreover, when melt | dissolution is inadequate, cooling and warming operation can also be repeated. Whether or not dissolution is sufficient can be judged only by visually observing the appearance of the solution.

In the cooling dissolution method, it is preferable to use a sealed container in order to avoid water mixing due to condensation during cooling. In addition, in a cooling heating operation, when it pressurizes at the time of cooling and depressurizes at the time of heating, a dissolution time can be shortened. In order to perform pressurization and pressure reduction, it is preferable to use a pressure-resistant container.

In addition, the 20 mass% solution which melt | dissolved cellulose acylate (degree of acetination: 60.9%, viscosity average degree of polymerization: 299) in methyl acetate by the cooling dissolution method was a sol state around 33 degreeC according to the measurement by a differential scanning calorimeter (DSC). The pseudo transition point between the gel state and the gel state exists, and below this temperature, a uniform gel state is obtained. Therefore, this solution needs to be maintained at a temperature above the pseudo phase transition temperature, preferably at a temperature of about 10 ° C. plus a gel phase transition temperature. However, this pseudo phase transition temperature differs depending on the degree of acetylation of the cellulose acylate, the viscosity average polymerization degree, the solution concentration, or the organic solvent used.                     

The cellulose acylate film is manufactured from the prepared cellulose acylate solution (dope) by the solvent cast method. The dope is cast on a support such as a drum or a band, and the solvent is evaporated to form a film. It is preferable to adjust the density | concentration of the dope before casting | flow_spread so that solid content may be 18 to 35%. It is preferable to finish the surface of a drum or a band in a mirror surface state. The dope is preferably cast on a drum or band having a surface temperature of 10 ° C or lower.

Regarding the drying method in the solvent cast method, U.S. Patents 2336310, 2367603, 2492078, 2492977, 2492978, 2607704, 2739069, 2739070, British Patent 640731, and 736892 Each specification of Unexamined-Japanese-Patent No. 45-4554, 49-5614, 60-176834, 60-203430, 62-115035 is described. Drying on a band or drum can be performed by blowing inert gas, such as air and nitrogen.

The obtained film may be removed from the drum or the band, and dried again with a high temperature wind of gradually changing the temperature to 100 to 160 ° C to evaporate the residual solvent. The above method is described in JP-A-5-17844. According to this method, the time from casting to peeling can be shortened. In order to carry out this method, it is necessary to gel dope at the surface temperature of the drum or band at the time of casting.

The cellulose acylate film of the present invention is preferably used by mixing the methylene chloride and alcohol as described above, but adjusting the I / O ratio (inorganic / organic ratio) of the residual solvent during peeling from a support such as a drum or a band. By starting the conveyance, a film having a small Re and Rth and a small variation in Re and Rth due to the use environment temperature and humidity can be obtained.

The I / O ratio is an index showing the magnitude of the concept of hydrophilicity of the compound, and can be calculated by the calculation method described in Sankyo Publication, Koda Yoshio, and the Organic Concept.

In the present invention, the I / O ratio of the mixed solvent containing M percent of solvent A and (100-M) percent of solvent A is represented by Ra, and the ratio of I / O of solvent B is Rb. If you do,

Ra × M / 100 + Rb × (100-M) / 100

Calculate by

As for the I / O ratio of the residual solvent at the time of peeling off the cellulose acylate film of this invention, 0.65 or more and 4 or less are preferable, 0.75 or more and 3 or less are more preferable, 0.9 or more and 2.5 or less are the most preferable.

Moreover, when the sum total of both methylene chloride and alcohol of the residual solvent at the time of peeling is 100 mass%, 10 mass% or more and 40 mass% or less of alcohol are preferable, and 15 mass% or more and 37 mass% or less More preferably, 20 mass% or more and 34 mass% or less are the most preferable.

Using the adjusted cellulose acylate solution (dope), two or more layers can be cast to form a film. In this case, it is preferable to manufacture a cellulose acylate film by the solvent cast method. The dope is flexible on a drum or band and the solvent is evaporated to form a film. As for the dope before casting | flow_spread, it is preferable to adjust density | concentration so that solid content may become 10 to 40% of range. It is preferable to finish the surface of the drum or the band in a mirror state.

When plural cellulose acylate liquids of two or more layers are cast, a plurality of cellulose acylate solutions can be cast, and a solution containing cellulose acylate is respectively cast from a plurality of oil studies formed at intervals in the advancing direction of the support. It is also possible to produce a film while laminating. For example, the method of Unexamined-Japanese-Patent No. 61-158414, Unexamined-Japanese-Patent No. 1-22419, and Unexamined-Japanese-Patent No. 11-198285 can be used. Moreover, it can also form into a film by casting a cellulose acylate solution from two oil studies. For example, Japanese Patent Application Laid-Open No. 60-27562, Japanese Patent Application Laid-Open No. 61-94724, Japanese Patent Application Laid-Open No. 61-947245, Japanese Patent Application Laid-Open No. 61-104813, Japanese Patent Application Laid-Open No. 61-158413 And the methods described in Japanese Unexamined Patent Publication No. Hei 6-134933. Moreover, the cellulose acylate film which surrounds the flow of the high viscosity cellulose acylate solution of Unexamined-Japanese-Patent No. 56-162617 with the low viscosity cellulose acylate solution, and simultaneously extrudes the high viscosity and low viscosity cellulose acylate solution Flexible methods can also be used.

Moreover, using two oil studies, the film formed by the support body by the 1st oil study can be removed, and a film can also be manufactured by performing 2nd casting | flow_spread to the side which contacted the support surface. For example, the method of Unexamined-Japanese-Patent No. 44-20235 is mentioned.

The flexible cellulose acylate solution may use the same solution or another cellulose acylate solution. In order to give a function to the some cellulose acylate layer, what is necessary is just to extrude the cellulose acylate solution suitable for the function from each oil research. In addition, the cellulose acylate solution of the present invention may be flexible at the same time as other functional layers (such as an adhesive layer, a dye layer, an antistatic layer, an antihalation layer, an ultraviolet absorbing layer, a polarizing layer, etc.).

In the conventional monolayer liquid, it is necessary to extrude the cellulose acylate solution of high viscosity at high concentration in order to make the thickness of a required film. In this case, the stability of the cellulose acylate solution was poor, and solids were generated, which caused protrusion failure or poor planarity. As a solution to this problem, by casting a plurality of cellulose acylate solutions from oil studies, it is possible to simultaneously extrude a high viscosity solution onto the support, to improve planarity, and to produce an excellent planar film. By using one cellulose acylate solution, reduction of dry load can be achieved and the production speed of a film can be raised.

A deterioration inhibitor (for example, antioxidant, peroxide decomposer, radical inhibitor, metal deactivator, acid trapping agent, and amine) can also be added to a cellulose acylate film. Deterioration inhibitors are described in Japanese Unexamined Patent Publications No. 3-199201, 5-1907073, 5-194789, 5-271471, and 6-107854. It is preferable that it is 0.01-1 mass% of the solution (dope) to prepare, and, as for the addition amount of a deterioration inhibitor, it is more preferable that it is 0.01-0.2 mass%. If the added amount is less than 0.01% by mass, the effect of the deterioration inhibitor is hardly seen. When the addition amount exceeds 1 mass%, the bleed out (exuding) of the deterioration inhibitor to the film surface may be observed. Examples of particularly preferred deterioration inhibitors include butylated hydroxytoluene (BHT) and tribenzylamine (TBA).

The winding machine used for manufacture of the cellulose acylate film used for this invention should just be what is generally used, and it can wind up by winding methods, such as the constant tension method, the static torque method, the taper tension method, and the internal stress constant program tension control method. I can wind it up.

[Glass Transition Temperature of Cellulose Acylate Film]

The measurement of the glass transition temperature of a cellulose acylate film can be performed by the method of JIS standard K7121.

80 degreeC or more and 200 degrees C or less are preferable, and, as for the glass transition temperature of the cellulose acylate film of this invention, 100 degreeC or more and 170 degrees C or less are more preferable. Glass transition temperature can be reduced by containing low molecular weight compounds, such as a plasticizer and a solvent.

[Film thickness]

Moreover, the thickness (dry film thickness) of a cellulose acylate film is 120 micrometers or less, 20-100 micrometers is preferable and 30-90 micrometers is more preferable.

[Retardation of Film]

In this specification, Re and Rth represent in-plane retardation and retardation of thickness direction, respectively. Re is measured by injecting light with a wavelength of 590 nm in the direction of the film normal in KOBRA 21ADH (manufactured by Ow Clock Co., Ltd.). Rth is a retardation value measured by injecting light having a wavelength of 590 nm from a direction inclined at + 40 ° to the film normal direction using the Re, the in-plane slow axis (as determined by KOBRA 21ADH) as the inclination axis (rotation axis). And retardation values measured in a total of three directions of retardation values measured by injecting light having a wavelength of 590 nm from a direction inclined at -40 ° to the film normal direction using the in-plane slow axis as the inclination axis (rotation axis). Based on this, KOBRA 21ADH is calculated. Here, the hypothesis of the average refractive index can be used as a polymer handbook (JOHN WILEY & SONS, INC) and catalog values of various optical films. If the value of the mean refractive index is not known, it can be measured with an Abbe refractometer. The value of the average refractive index of the main optical film is illustrated below: cellulose acelate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), polystyrene (1.59). By inputting the assumption values and the film thicknesses of these average refractive indices, KOBRA 21ADH calculates nx, ny, and nz.

The cellulose acylate film of this invention can be used suitably as an optical compensation film for liquid crystal display devices in combination with another optically anisotropic layer or retardation film.

In this case, from the viewpoint of viewing angle dependency, the absolute value of Rth measured at 25 ° C. 60% RH of the cellulose acylate film is preferably 25 nm or less, more preferably 20 nm or less, most preferably 10 nm or less. Re measured at 25 ° C 60% RH is preferably 0 nm or more and 20 nm or less, more preferably 0 nm or more and 10 nm or less, and more preferably 0 nm or more and 5 nm or less.

In one aspect of the cellulose acylate film of the present invention having a small change due to the temperature-humidity of the optical characteristic, the absolute value of the difference between the Rth of 25 ° C and 10% RH and the Rth of 25 ° C and 80% RH is 40 nm or less. In another embodiment, the absolute value of the difference between Re at 25 ° C and 10% RH and Re at 25 ° C and 80% RH is 20 nm or less.

Moreover, 120 micrometers or less are preferable, as for the thickness (dry film thickness) of a cellulose acylate film, 20-110 micrometers is more preferable, 40-100 micrometers is the most preferable.

[Surface Treatment of Cellulose Acylate Film]

It is preferable to surface-treat a cellulose acylate film. Specific methods include corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment or ultraviolet irradiation treatment. Moreover, as described in Unexamined-Japanese-Patent No. 7-333433, it is also preferable to form a undercoat layer.

When using the cellulose acylate film of this invention as a transparent protective film of a polarizing plate, it is especially preferable to perform acid treatment or alkali treatment, ie, saponification process with respect to a cellulose acylate, from an adhesive viewpoint with a polarizer.

The surface energy is preferably 55 mN / m or more, more preferably 60 mN / m or more and 75 mN / m or less.

The alkali saponification treatment will now be described in detail.

The alkali saponification treatment of the cellulose acylate film is preferably performed in a cycle in which the film surface is immersed in an alkaline solution, neutralized with an acidic solution, washed with water and dried.

Examples of the alkali solution include a potassium hydroxide solution and a sodium hydroxide solution. The prescribed concentration of hydroxide ions is preferably in the range of 0.1 to 3.0 N, more preferably in the range of 0.5 to 2.0 N. The alkali solution temperature is preferably in the range from room temperature to 90 ° C, more preferably in the range from 40 to 70 ° C.

The surface energy of a solid can be calculated | required by the contact angle method, the wet heat method, and the adsorption method as described in "The basis and application of wetness" (issued by Riarise Co., 1989.12.10). In the case of this cellulose acylate film, it is preferable to use a contact angle method.

Specifically, two solutions containing known surface energy are added dropwise to the cellulose acylate film, and at the intersection between the surface of the droplet and the film surface, the liquid containing the droplet at an angle formed by the tangent drawn on the droplet and the surface of the film. The angle of is defined as a contact angle, and the surface energy of the film can be calculated by calculation.

[Water Content of Cellulose Acylate Film]

The water absorption of the cellulose acylate film can be evaluated by measuring the equilibrium moisture content at a constant temperature and humidity. The equilibrium water content is calculated by dividing the amount of water (g) by the sample mass (g) by measuring the amount of water in the sample that has reached equilibrium after allowing it to stand at constant temperature and humidity for 24 hours.

The equilibrium moisture content at 25 ° C 80% RH of the cellulose acylate film of the present invention is preferably 6 mass% or less, more preferably 4 mass% or less, and most preferably 3.5 mass% or less.

[Water vapor transmission rate]                     

The moisture permeability measures the moisture permeability of each sample by the method described in JIS Z 0208, and is calculated as the amount of water (g) evaporated for 24 hours per 1 m 2 of area.

The water vapor transmission rate of a cellulose acylate film can be adjusted by various methods. The water vapor transmission rate can be reduced by adding a hydrophobic compound to a cellulose acylate film and reducing the water absorption of a cellulose acylate film.

In addition, the moisture permeability can also be reduced by stretching in the conveying direction and / or the width direction during film formation and densifying the orientation in the molecular chain of cellulose acylate.

Stretching may be performed by either uniaxial stretching or biaxial stretching.

Biaxial stretching includes simultaneous biaxial stretching and sequential biaxial stretching, but from the viewpoint of continuous manufacturing, sequential biaxial stretching is preferred. After dope is flexible, the film is removed from the band or drum and stretched in the width direction (length direction). After that, the film is stretched in the longitudinal direction (width direction).

As a method of extending | stretching in the width direction, each publication, such as Unexamined-Japanese-Patent No. 62-115035, Unexamined-Japanese-Patent No. 4-152125, 4-284211, 4-298310, 11-48271, etc. is mentioned, for example. It is described in. Stretching of a film is performed under normal temperature or heating conditions. The heating temperature is preferably below the glass transition temperature of the film. The film can be stretched by the treatment during drying, and is particularly effective when a solvent remains. In the case of the stretching in the longitudinal direction, for example, by adjusting the speed of the conveying roller of the film and making the winding speed of the film faster than the peeling speed of the film, the film is stretched. In the case of extending | stretching of the width direction, it can convey, maintaining a width of a film with a tenter, and extending | stretching a film can also extend | stretch the width of a tenter gradually. After drying of the film, stretching using a stretching machine (preferably uniaxial stretching using a long stretching machine) is also possible. The stretching ratio of the film (ratio of increase by stretching to original length) is preferably in the range of 5 to 50%, more preferably in the range of 10 to 40%, most preferably in the range of 15 to 35%. desirable.

As for the water vapor transmission rate of the cellulose acylate film of this invention measured by the method of JIS Z 0208, the condition A (after measuring for 24 hours in 25 degreeC 90% RH atmosphere), 20 g / m <2> or more and 250 g / m <2> or less are preferable, and 40g / M 2 or more and 225 g / m 2 or less are more preferable, and 100 g / m 2 or more and 200 g / m 2 or less are most preferable.

[Hygroscopic expansion coefficient]

The moisture absorption expansion coefficient represents the amount of change in the sample length when the relative humidity is changed under a certain temperature.

In order to prevent the increase in the transmittance of the frame shape, the moisture absorption expansion coefficient of the cellulose acylate film is preferably 30 × 10 ⁻⁵ /% RH or less, more preferably 15 × 10 ⁻⁵ /% RH or less, Most preferably, it is 10x10 <^-5> /% RH or less. In addition, although the moisture absorption expansion coefficient is small, it is usually a value of 1.0x10 <^-5> /% RH or more.

It shows below about the measuring method of a moisture absorption expansion coefficient. The sample of width 5mm and length 20mm was cut out from the produced polymer film (retardation plate), and one end was fixed, and it was suspended in 25 degreeC and 20% RH (R0) atmosphere. A 0.5 g weight was hung on the other end and left for 10 minutes to measure the length (L0). Next, in the state of 25 degreeC, the humidity was made into 80% RH (R1), and length L1 was measured. The hygroscopic expansion coefficient was calculated by the following equation. The measurement performed 10 samples with respect to the same sample, and adopted the average value.

Hygroscopic expansion coefficient [/% RH] = {(L1-L0) / L0} / (R1-R0)

In order to reduce the dimensional change due to moisture absorption, it is preferable to reduce the amount of residual solvent during film formation to reduce the free volume in the polymer film.

The general technique for reducing residual solvent is to dry at a high temperature for a long time, but if it is too long, of course, productivity decreases. Therefore, the amount of the residual solvent with respect to the cellulose acylate film is preferably in the range of 0.01 to 1% by mass, more preferably in the range of 0.02 to 0.07% by mass, and most preferably in the range of 0.03 to 0.05% by mass.

By controlling the amount of the residual solvent, a polarizing plate having optical compensation ability can be produced at low cost and high productivity.

The residual solvent amount was measured by dissolving a certain amount of sample in chloroform and using a gas chromatograph (GC18A) and Shimadzu Corporation.

In the solution softening method, a film is prepared using a solution (dope) in which a polymer material is dissolved in an organic solvent. As described later, drying in the solution softening method is largely divided into drying on the drum (or band) surface and drying at the time of conveyance of the film. In the case of drying on the drum (or bend) side, it is preferable to dry slowly at a temperature not exceeding the boiling point of the solvent in use (if it exceeds the boiling point, it becomes a foam). Moreover, it is preferable to perform drying at the time of film conveyance at the glass transition point of a polymer material at +/- 30 degreeC, More preferably, to +/- 20 degreeC.

Moreover, it is preferable to add the compound which has a hydrophobic group as another method of making the dimensional change by the said moisture absorption small. The material having a hydrophobic group is not particularly limited as long as it is a material having a hydrophobic group such as an alkyl group or a phenyl group in the molecule, and a material corresponding to the plasticizer or anti-degradant added to the cellulose acylate film is particularly preferably used. Examples of these preferred materials include triphenylphosphate (TPP), tribenzylamine (TBA), and the like.

It is preferable to exist in 0.01-30 mass% with respect to the solution (dope) to adjust, and, as for the addition amount of the compound which has these hydrophobic groups, it is more preferable to exist in 0.1-20 mass% range.

[Dimension Change Rate]

The dimensional change rate of a cellulose acylate film can measure the dimensional change before and after time at a fixed temperature with a pin gauge, L1 can be calculated by the following formula, let L1 be the dimension before time, and L2 after the time.

Dimensional rate of change (%) = [(L2-L1) / L1] × 100

The dimensional change rate of the cellulose acylate film of the present invention at 90 ° C. over 24 hours is preferably -0.5% or more and 0.5% or less, more preferably -0.3% or more and 0.3% or less, most preferably -0.2% or more and 0.2% or less desirable.

[Elastic Modulus of Cellulose Acylate Film]

The elastic modulus of the cellulose acylate film can be obtained by a tensile test. The cellulose acylate film of the present invention preferably has a modulus of elasticity in the plane of at least one direction (preferably in the width direction or the flexible direction) of 1.0 GPa or more and 6.0 GPa or less, more preferably 2.0 GPa or more and 5.5 GPa or less, and 2.5 GPa or more 5.0 kPa or less is most preferable.

[Photoelasticity]

The photoelastic coefficient of the cellulose acylate film of the present invention is preferably 60 × 10 ^-8 cm 2 / N or less, more preferably 20 × 10 ^-8 cm 2 / N or less. The photoelastic coefficient can be obtained by ellipsometer.

Next, the polarizing plate of this invention is demonstrated.

1. Composition of Polarizer

First, the protective film and polarizer which comprise the polarizing plate of this invention are demonstrated.

The polarizing plate of this invention may have an adhesive layer, a separator film, and a protective film as a component other than a polarizer and a protective film.

(1) protective film

Although the polarizing plate of this invention has two pieces of protective films in total by one piece on both sides of a polarizer, it is preferable that at least one of these has a function as retardation film together.

The protective film of the present invention is preferably a polymer film made of norbornene resin, polyethylene terephthalate, polystyrene naphthalate, polycarbonate, polystyrene, polyallylate, polysulfone, cellulose acylate and the like.

Among these, the said cellulose acylate is the most preferable.

(2) polarizer

The polarizer of the present invention is preferably composed of polyvinyl alcohol (PVA) and dichroic molecules. However, as described in Japanese Patent Laid-Open No. 11-248937, the polarizer is dehydrated and dechlorinated to remove poly The polyvinylene polarizer which produced the yen structure and orientated this can also be used.

Although PVA is a polymer material which saponified polyvinyl acetate, it may contain the component copolymerizable with vinyl acetate, such as unsaturated carboxylic acid, unsaturated sulfonic acid, olefins, vinyl ethers, for example. Moreover, modified PVA containing acetoacetyl group, sulfonic acid group, carboxyl group, oxyalkylene group, etc. can also be used.

Although the saponification degree of PVA is not specifically limited, From a viewpoint of solubility, etc., 80-100 mol% is preferable and 90-100 mol% is especially preferable. Moreover, although the polymerization degree of PVA is not specifically limited, 1000-10000 are preferable and 1500-5000 are especially preferable.

The syndiotacticity of PVA is preferably 55% or more in order to improve durability as described in Japanese Patent No. 2978219, but 45 to 52.5% described in Japanese Patent No. 3317494 can also be preferably used. .

After PVA film-forming, it is preferable to introduce | transduce a dichroic molecule and comprise a polarizer. As the method for producing a PVA film, a method of flexibly forming a film of a stock solution obtained by dissolving PVA-based resin in water or an organic solvent is generally used. The concentration of polyvinyl alcohol-based resin in the stock solution is usually 5 to 20% by mass, and a PVA film having a film thickness of 10 to 200 µm can be produced by forming the stock solution by a casting method. The production of the PVA film can be carried out with reference to Japanese Patent No. 3342516, Japanese Patent Application Laid-Open No. 09-328593, Japanese Patent Application Laid-Open No. 2001-302817, and Japanese Patent Application Laid-Open No. 2002-144401.

Although the crystallinity degree of a PVA film is not specifically limited, 50-75 mass% of average crystallinity degree (Xc) described in Unexamined-Japanese-Patent No. 332573, and it describes in Unexamined-Japanese-Patent No. 2002-236214 in order to reduce in-plane color variation. A PVA film having a degree of crystallinity of 38% or less can be used.

It is preferable that birefringence ((DELTA) n) of a PVA film is small, and the PVA film whose birefringence described in Japanese Patent No. 3342516 is 1.0x10 <^-3> or less can be used preferably. However, as described in JP 2002-228835 A, the birefringence of the PVA film may be 0.02 or more and 0.01 or less, in order to obtain high polarization while avoiding cutting during stretching of the PVA film. As described in 2002-060505, the value of (nx + ny) / 2-nz may be 0.0003 or more and 0.01 or less. 0 nm or more and 100 nm or less are preferable, and, as for the retardation (in-plane) of a PVA film, 0 nm or more and 50 nm or less are more preferable. Moreover, 0 nm or more and 500 nm or less are preferable, and, as for Rth (film thickness direction) of a PVA film, 0 nm or more and 300 nm or less are more preferable.

In addition, in the polarizing plate of the present invention, a PVA film having a 1,2-glycol bond amount described in Japanese Patent No. 3021494 or less and 1.5 mol% or less, and an optical foreign material of 5 μm or more described in Japanese Unexamined Patent Publication No. 2001-316492 PVA films having 500 or less P100 per 100 cm 2, PVA films having a hydrothermal cleavage temperature variation in the TD direction of the film described in JP-A-2002-030163, 1.5 ° C. or lower, and polyhydric alcohols such as glycerin and trivalent hexavalent polyhydric alcohols such as PVA 100 PVA film which mix | blended 1-100 mass parts per mass part, or formed into a solution which mixed 15 mass% or more of the plasticizers of Unexamined-Japanese-Patent No. 06-289225 can be used preferably.

Although the film film thickness before extending | stretching a PVA film is not specifically limited, 1 micrometer-1 mm are preferable from a viewpoint of the stability of film retention and the homogeneity of extending | stretching, and 20-200 micrometers is especially preferable. As described in Japanese Laid-Open Patent Publication No. 2002-236212, a thin PVA film in which the stress generated when stretching four times to six times in water is 10 N or less can also be used.

As the dichroic molecule, higher order iodine ions or dichroic dyes such as I ₃ ^- and I ₅ ^- can be preferably used. In the present invention, higher order iodine ions are particularly preferably used. Higher-order iodine ions are described in "Application of Polarizing Plates", CMC Publications and Industrial Materials, Vol. 28, No. 7, p39-p45, and / or boric acid solution of iodine in an aqueous solution of potassium iodide. PVA is immersed in aqueous solution, and it can produce | generate in the state which adsorbed and aligned to PVA.

When using a dichroic dye as a dichroic molecule, an azo dye is preferable and a bis azo dye and a tris azo dye are especially preferable. The dichroic dye is preferably a water-soluble one, and for this reason, hydrophilic substituents such as sulfonic acid groups, amino groups and hydroxyl groups are introduced into the dichroic molecules, and are preferably used as free acids or salts of alkali metal salts, ammonium salts and amines.

Specific examples of such dichroic dyes include, for example, CIDirect Red 37, Congo Red (CIDirect Red 28), CIDirect Violet 12, CIDirect Blue 90, CIDirect Blue 22, CIDirect Blue 1, CIDirect Blue 151. , Benzidine series such as CIDirect Green 1, diphenyl urea series such as CIDirect Yellow 44, CIDirect Red 23, CIDirect Red 79, stilbene series such as CIDirect Yellow 12, and dinaphthylamine such as CIDirect Red 31 And J oxygen such as CIDirect Red 81, CIDirect Violet 9, and CIDirect Blue 78.

In addition, CIDirect Yellow 8, CIDirect Yellow 28, CIDirect Yellow 86, CIDirect Yellow 87, CIDirect Yellow 142, CIDirect Orange 26, CIDirect Orange 39, CIDirect Orange 72, CIDirect Orange 106, CIDirect Orange 107, CIDirect Red 2, CIDirect Red 39, CIDirect Red 83, CIDirect Red 89, CIDirect Red 240, CIDirect Red 242, CIDirect Red 247, CIDirect Violet 48, CIDirect Violet 51, CIDirect Violet 98, CIDirect Blue 15, CIDirect Blue 67, CIDirect Blue 71, CIDirect Blue 98, CIDirect Blue 168, CIDirect Blue 202, CIDirect Blue 236, CIDirect Blue 249, CIDirect Blue 270, CIDirect Green 59, CIDirect Green 85, CIDirect Brown 106, CIDirect Brown 195, CIDirect Brown 210, CIDirect Brown 223, CIDirect Brown 224, CIDirect Black 1, CIDirect Black 17, CIDirect Black 19, CIDirect Black 54 and the like, and further, JP-A-62-70802, JP-A-1-161202, JP-A-172906 , Japanese Unexamined Patent Publication No. Hei 1-72907, Japanese Unexamined Patent Publication No. Hei 1-83602, Japanese Unexamined Patent Publication No. Hei 1-248105, Japanese Patent Application Laid-open No. Hei 1-265205, The dichroic dye described in each publication can also be used preferably.

In order to produce dichroic molecules having various colors, these dichroic dyes may be used in combination of two or more kinds. When using a dichroic dye, adsorption thickness may be 4 micrometers or more, as described in Unexamined-Japanese-Patent No. 2002-082222.

If the content of this dichroic molecule in the film is too small, the polarization degree is low, and even if the content of the dichroic molecule is too high, the single plate transmittance is lowered, so that the polyvinyl alcohol-based polymer constituting the matrix of the film is usually in the range of 0.01% by mass to 5% by mass. Adjusted.

A (편광자 막두께)/B (보호막 막두께)

0.16 범위로 하는 것도 바람직하다.As a preferable film thickness of a polarizer, 5 micrometers-40 micrometers are preferable, More preferably, they are 10 micrometers-30 micrometers. The ratio of the thickness of a polarizer and the thickness of the protective film mentioned later is 0.01 described in Unexamined-Japanese-Patent No. 2000-174727.

A (polarizer film thickness) / B (shield film thickness)

It is also preferable to set it as 0.16 range.

Although the arbitrary value may be sufficient as the crossing angle of the slow axis of a protective film, and the absorption axis of a polarizer, it is preferable that it is parallel or the azimuth angle of 45 +/- 20 degrees.

2. Manufacturing process of polarizing plate

Next, the manufacturing process of the polarizing plate of this invention is demonstrated.

It is preferable that the manufacturing process of the polarizing plate in this invention consists of a swelling process, a dyeing process, a film-forming process, an extending process, a drying process, a protective film bonding process, and a post-bonding drying process. May be changed arbitrarily, and several processes may be combined and performed simultaneously. Moreover, as described in the specification of 3333615, washing with water after a film-forming process can also be performed preferably.

In the present invention, it is particularly preferable to sequentially perform the swelling step, the dyeing step, the dura mating step, the stretching step, the drying step, the protective film bonding step, and the post-bonding drying step in the described order. In addition, you may provide an online surface inspection process during or after the process mentioned above.

The swelling step is preferably performed only with water. However, as described in Japanese Patent Application Laid-open No. Hei 10-153709, the polarizing plate substrate is applied to an aqueous solution of boric acid to stabilize optical properties and avoid wrinkle occurrence of the polarizing plate substrate in a production line. By swelling, and the degree of swelling of the polarizing plate substrate can also be managed.

In addition, although the temperature and time of a swelling process can be arbitrarily determined, 10 degreeC or more and 60 degrees C or less, 5 second or more and 2000 second or less are preferable.

The dyeing process can use the method of Unexamined-Japanese-Patent No. 2002-86554. In addition, as a dyeing method, arbitrary means, such as application | coating or spraying of iodine or a dye solution, as well as dipping, are possible. As described in Japanese Unexamined Patent Application Publication No. 2001-290025, a method of dyeing with stirring the concentration of iodine, the dye bath temperature, the draw ratio in the bath, and the solution in the bath can also be used.

When using higher order iodine ion as a dichroic molecule, in order to obtain a high contrast polarizing plate, it is preferable to use the liquid which melt | dissolved iodine in the aqueous solution of potassium iodide for a dyeing process. In this case, the iodine of the aqueous solution of potassium iodide is 0.05-20 g / l, the potassium iodide is 3-200 g / l, and the mass ratio of iodine and potassium iodide is 1-2000. 10-1200 second of dyeing time is preferable, and 10-60 degreeC of liquid temperature is preferable. More preferably, iodine is 0.5-2 g / l, potassium iodide is 30-120 g / l, mass ratio of iodine and potassium iodide is 30-120, the dyeing time is 30-600 seconds, and the liquid temperature is 20-50 degreeC. good.

As described in the specification of Patent No. 3145747, boron-based compounds such as boric acid and borax may also be added to the dyeing solution.

It is preferable that a film-forming process contains a crosslinking agent by immersing in a crosslinking agent solution or apply | coating a solution. Moreover, as described in Unexamined-Japanese-Patent No. 11-52130, a dura mater process can also be performed in several times.

As the crosslinking agent, those described in US Reissue Patent No. 232897 may be used. In order to improve dimensional stability as described in Patent No. 3357109, polyhydric aldehyde may be used as the crosslinking agent, but boric acids are most preferably used. .                     

When boric acid is used as a crosslinking agent used for a film-forming process, metal ion can also be added to boric-acid potassium iodide aqueous solution. Although zinc chloride is preferable as the metal ion, zinc salts such as zinc halides such as zinc iodide, zinc sulfate, and zinc nitrate may be used in place of zinc chloride, as described in JP-A-2000-35512.

In the present invention, it is preferable to prepare a boric acid-potassium iodide aqueous solution to which zinc chloride is added, and to immerse the PVA film to perform a dura mater. The boric acid is preferably 1 to 100 g / l, the potassium iodide to 1 to 120 g / l, the zinc chloride is preferably 0.01 to 10 g / l, the film formation time is 10 to 200 seconds, and the liquid temperature is preferably 10 to 60 ° C. More preferably, boric acid is 10-80 g / l, potassium iodide is 5-100 g / l, zinc chloride is 0.02-8 g / l, film-forming time is 30-600 second, and liquid temperature is 20-50 degreeC.

(보호막 접합시의 편광자 폭/최종 욕을 나왔을 때의 편광자의 폭)

0.95 로 하는 것도 바람직하게 실행할 수 있다.The stretching step may preferably be a one-day stretching method, as described in US Patent No. 2,454, 515, or the like, or a tenter method as described in JP-A-2002-86554. Preferable draw ratios are 2 times or more and 12 times or less, More preferably, they are 3 times or more and 10 times or less. In addition, the relationship between the draw ratio, the disk thickness, and the polarizer thickness is set to (Polarizer film thickness / disk thickness after protective film bonding) × (total draw ratio)> 0.17 described in JP-A-2002-040256, and the final bath The relationship between the width of the polarizer at the time of exiting and the width of the polarizer at the time of protective film bonding is 0.80 described in Japanese Patent Laid-Open No. 2002-040247.

(Width of the polarizer when out of polarizer width / final bath at the time of protective film bonding)

0.95 can also be preferably performed.

The drying process may use a method known in Japanese Laid-Open Patent Publication No. 2002-86554, but a preferable temperature range is 30 ° C to 100 ° C, and a preferable drying time is 30 seconds to 60 minutes. In addition, as described in patent 3148513, a heat treatment is performed in which the water color fading temperature is 50 ° C. or higher, or as described in JP-A-07-325215 or JP-A-07-325218. Aging in an atmosphere in which temperature and humidity is managed can also be preferably performed.

A protective film bonding process is a process of bonding both surfaces of the above-mentioned polarizer which exited the drying process with two protective films. The method of bonding with a pair of rolls is used preferably so that an adhesive liquid may be supplied just before joining, and a polarizer and a protective film may overlap. Moreover, in order to suppress the groove-shaped unevenness | corrugation of the record resulting from extending | stretching of a polarizer as described in Unexamined-Japanese-Patent No. 2001-296426 and 2002-86554, the moisture content of the polarizer at the time of bonding is adjusted. It is desirable to. In this invention, the moisture content of 0.1%-30% is used preferably.

Although the adhesive agent of a polarizer and a protective film is not specifically limited, PVA system resin (containing modified PVA, such as an acetacetyl group, a sulfonic acid group, a carboxyl group, an oxyalkylene group), an aqueous solution of a boron compound, etc. are mentioned, Especially, PVA system resin is mentioned. Is preferred. 0.01-5 micrometers is preferable and, as for an adhesive bond layer thickness, 0.05-3 micrometers is especially preferable.

In addition, in order to improve the adhesive force of a polarizer and a protective film, it is preferable to carry out the surface treatment of a protective film, and to make it adhere | attach after making it hydrophilic. Although the method of surface treatment is not specifically limited, Well-known methods, such as the method of saponifying using alkaline solution and the corona treatment method, can be used. Moreover, you may form easily bonding layers, such as a gelatin undercoat layer, after surface treatment. As described in Japanese Patent Laid-Open No. 2002-267839, the contact angle with water on the surface of the protective film is preferably 50 ° or less.

Although the drying conditions after bonding are based on the method of Unexamined-Japanese-Patent No. 2002-86554, the preferable temperature range is 30 degreeC-100 degreeC, and is 30 second-60 minutes in preferable drying time. Moreover, as described in Unexamined-Japanese-Patent No. 07-325220, it is also preferable to age in the atmosphere which controlled temperature-humidity.

The element content in the polarizer is preferably 0.1 to 3.0 g / m 2 of iodine, 0.1 to 5.0 g / m 2 of boron, 0.1 to 2.0 g / m 2 of potassium, and 0 to 2.0 g / m 2 of zinc. In addition, potassium content may be 0.2 mass% or less as described in Unexamined-Japanese-Patent No. 2001-166143, and zinc content in a polarizer is 0.04 mass%-0.5 mass% described in Unexamined-Japanese-Patent No. 2000-035512. You can also do

As described in Japanese Patent No. 3323255, in order to increase the dimensional stability of the polarizing plate, an organic titanium compound and / or an organic zirconium compound are added and used in any one of a dyeing step, an extending step and a film forming step, and an organic titanium compound And at least one compound selected from organic zirconium compounds. In addition, a dichroic dye may be added to adjust the color of the polarizing plate.

3. Characteristics of polarizer                     

(1) transmittance and polarization degree

Although the preferable single plate transmittance of the polarizing plate of this invention is 42.5% or more and 49.5% or less, More preferably, they are 42.8% or more and 49.0% or less. The preferable range of polarization degree defined by following formula (4) is 99.900% or more and 99.999% or less, More preferably, it is 99.940% or more and 99.995% or less. The preferred range of parallel transmittance is 36% or more and 42% or less, and the preferred range of orthogonal transmittance is 0.001% or more and 0.05% or less. Although the preferable range of the dichroism ratio defined by following formula (5) is 48 or more and 1215 or less, More preferably, they are 53 or more and 525 or less.

The above-mentioned transmittance is defined by the following formula (2) based on JIS Z8701.

Equation 2

[1]

In said Formula (2), K, S ((lambda)), y ((lambda)), (tau) (lambda) are as follows.

(3)

[Number 2]

S (λ): Spectral distribution of standard light used for color display                     

y (λ): Orange function in XYZ system

τ (λ): Spectral transmittance

(Equation 4)

[Number 3]

(5)

[4]

The iodine concentration and the single plate transmittance may be in the range described in Japanese Laid-Open Patent Publication No. 2002-258051.

The parallel transmittance may have a small wavelength dependency, as described in Japanese Unexamined Patent Application Publication No. 2001-083328 or 2002-022950. The optical characteristic in the case of arranging the polarizing plates in cross nicols may be in the range described in JP 2001-091736, and the relationship between parallel transmittance and orthogonal transmittance is in the range described in JP 2002-174728. Maybe tomorrow.

As described in Japanese Laid-Open Patent Publication No. 2002-221618, the standard deviation of parallel transmittance every 10 nm between the wavelength of light and 420 to 700 nm is 3 or less, and the wavelength of light is between 420 and 700 nm. The minimum value of (parallel transmittance / orthogonal transmittance) per 10 nm may be 300 or more.

Parallel transmittance and orthogonal transmittance at wavelength 440 nm of the polarizing plate, parallel and orthogonal transmittance at wavelength 550 nm, and parallel and orthogonal transmittance at wavelength 610 nm are disclosed in Japanese Patent Application Laid-Open No. 2002-258042 or JP 2002-2002A. The range described in 258043 can also be preferably executed.

(2) color

The color of the polarizing plate of the present invention is preferably evaluated using the brightness index L * and chromaticity index a * and b * in the L * a * b * color system which is recommended as a CIE equal perceptual space.

L *, a *, b * are defined by the following formula (6) using X, Y, Z described above.

(6)

[Number 5]

Here, X ₀ , Y ₀ , Z ₀ represents the tristimulus value of the illumination light source, for standard light C, X ₀ = 98.072, Y ₀ = 100, Z ₀ = 118.225, and for standard light D ₆₅ , ₀ = 95.045, Y ₀ = 100, Z ₀ = 108.892.

The range of preferable a * of one polarizing plate is -2.5 or more and 0.2 or less, More preferably, it is -2.0 or more and 0 or less. The range of preferable b * of one polarizing plate is 1.5 or more and 5 or less, More preferably, it is 2 or more and 4.5 or less. The preferable range of a * of parallel transmitted light of two polarizing plates is -4.0 or more and 0 or less, More preferably, they are -3.5 or more and -0.5 or less. The preferable range of b * of parallel transmitted light of two polarizing plates is 2.0 or more and 8 or less, More preferably, it is 2.5 or more and 7 or less. The preferable range of a * of orthogonal light of two polarizing plates is -0.5 or more and 1.0 or less, More preferably, it is 0 or more and 2 or less. The preferable range of b * of orthogonal light of two polarizing plates is -2.0 or more and 2 or less, More preferably, they are -1.5 or more and 0.5 or less.

The color may be evaluated by the chromaticity coordinates (x, y) calculated from the above-described X, Y, and Z, for example, the chromaticity (x _p , y _p ) of the parallel transmitted light of the two polarizing plates and the chromaticity of the orthogonal transmitted light (x _c). , y _c ) is in the range described in JP-A-2002-214436, JP-A-2001-166136 and JP-A-2002-169024, or the relationship between color and absorbance is JP-A-2001. It is also possible to carry out within the range described in -311827.

(3) viewing angle characteristics

Transmittance ratio and xy chromaticity difference in the case where vertical light is incident when the polarizing plate is arranged in cross nicol and the light having a wavelength of 550 nm is incident, and when the polarizing plate is incident at an angle of 40 degrees with respect to the normal from a 45 degree orientation with respect to the polarization axis. It is also preferable to set it as the range of Unexamined-Japanese-Patent No. 2001-166135 and Unexamined-Japanese-Patent No. 2001-166137. Further, Japanese Laid-open as described in Patent Application No. Hei 10-068817, the light transmittance of the crossed-Nicol arrangement in the vertical direction, a polarizing plate laminated body (T ₀₎ and, 60 ° oblique direction from the light transmission of the laminate of the normal ( T ₆₀ ) and the ratio (T ₆₀ / T ₀ ) to 10000 or less, or as described in Japanese Patent Laid-Open No. 2000-139625, incident natural light at any angle from the normal to the elevation angle of 80 degrees in the polarizing plate In the case of the above, the transmittance difference of the transmitted light within the wavelength range of 20 nm within the wavelength range of 520 to 640 nm of the transmission spectrum is 6% or less, or is described in JP 08-248201A. It is also preferable to set the luminance difference of the transmitted light at an arbitrary distance of 1 cm within 30%.

(4) durability

(4-1) Moist Heat Durability

As described in Japanese Unexamined Patent Publication No. 2001-116922, it is preferable that the rate of change of light transmittance and polarization degree before and after the case of being left at 60 ° C. and 90% RH atmosphere for 500 hours is 3% or less based on absolute values. . In particular, the change rate of light transmittance is 2% or less, and the change rate of polarization degree is preferably 1.0% or less, more preferably 0.1% or less, based on the absolute value. Moreover, as described in Unexamined-Japanese-Patent No. 07-077608, it is also preferable that polarization degree after being left to stand 80 degreeC, 90% RH, and 500 hours is 95% or more and single transmittance is 38% or more.                     

(4-2) dry durability

It is preferable that the change rate of the light transmittance and polarization degree before and after when it is left to stand for 80 hours at 80 degreeC and dry atmosphere is 3% or less based on absolute value. In particular, the change rate of light transmittance is 2% or less, and the change rate of polarization degree is preferably 1.0% or less, more preferably 0.1% or less, based on the absolute value.

(4-3) other durability

In addition, as described in Japanese Patent Application Laid-Open No. 06-167611, the shrinkage after leaving for 2 hours at 80 ° C is 0.5% or less, or the polarizing plate laminate having cross nicol arrangement on both surfaces of the glass plate is 750 in an atmosphere of 69 ° C. X value and y value after leaving for a time to fall within the range described in JP-A-10-068818, or 105 cm ^-1 by Raman spectroscopy after 200 hours in 80 ° C, 90% RH atmosphere. It is also preferable to make the change of the spectral intensity ratio of 157 cm <^-1> into the range as described in Unexamined-Japanese-Patent No. 08-094834 and 09-197127.

(5) orientation

The higher the degree of orientation of the PVA, the better polarization performance is obtained, but 0.2 to 1.0 is a preferred range as an order parameter value calculated by means such as polarized Raman scattering or polarized light FT-IR. Further, as described in Japanese Laid-Open Patent Publication No. 59-133509, the difference between the orientation coefficient of the polymer segment in the entire amorphous region of the polarizer and the orientation coefficient (0.75 or more) of the occupant molecule is at least 0.15, or Japan As described in Japanese Patent Application Laid-Open No. 04-204907, the orientation coefficient of the amorphous region of the polarizer is 0.65 to 0.85, or the degree of orientation of the higher order iodine ions of I ₃ or I ₅ is 0.8 to 1.0 as the order parameter value. It is also possible to carry out preferably.

(6) other characteristics

As described in JP 2002-006133 A, the shrinkage force in the absorption axis direction per unit width when heated at 80 ° C. for 30 minutes is 4.0 N / cm or less, or is described in JP 2002-236213 A. As described above, when the polarizing plate is placed under a heating condition of 70 ° C. for 120 hours, the dimensional change rate in the absorption axis direction and the dimensional change rate in the polarization axis direction of the polarizing plate are both within ± 0.6%, or the moisture content of the polarizing plate is disclosed in JP 2002-090546 A. As described, it can also be preferably set to 3% by mass or less. In addition, as described in Japanese Unexamined Patent Application Publication No. 2000-249832, the surface roughness in the direction perpendicular to the stretching axis becomes 0.04 µm or less based on the center line average roughness, or described in Japanese Unexamined Patent Publication No. 10-268294. As described above, the refractive index n ₀ in the transmission axis direction is larger than 1.6, or the relationship between the thickness of the polarizing plate and the protective film thickness can also be preferably performed in the range described in JP-A-10-111411.

4. Functionalization of Polarizer

The polarizing plate of the present invention is a viewing angle magnification film of an LCD, a λ / 4 plate for applying to a reflective LCD, an antireflection film for improving the visibility of a display, a brightness enhancement film, a hard coat layer, a front scattering layer, an antiglare (anti-glare) It is preferably used as a functionalized polarizing plate in combination with an optical film having a functional layer such as a layer.

The structural example which combined the polarizing plate of this invention and the above-mentioned functional optical film is shown in FIG. As the protective film on one side of the polarizing plate, the functional optical film and the polarizer may be adhered through an adhesive (FIG. 1 (A)), or the functional optical film may be adhered to the polarizing plate having a protective film formed on both surfaces of the polarizer through an adhesive. 1 (B)). In the former case, an arbitrary transparent protective film can be used for the other protective film. It is also preferable to set the peeling strength between each layer, such as a functional layer and a protective film, to 4.0N / 25mm or more as described in Unexamined-Japanese-Patent No. 2002-311238. It is preferable to arrange | position a functional optical film in the liquid crystal module side according to the function aimed at, or arrange | positioning on the opposite side to a liquid crystal module, ie, a display side or a backlight side.

Hereinafter, a functional optical film used in combination with the polarizing plate of the present invention will be described.

(1) viewing angle magnification film

Polarizing plate of the present invention and the viewing angle magnification film proposed in display modes such as twisted nematic (TN), In-Plane Switching (IPS), Optically Compensatory Bend (OCB), Vertically Aligned (VA), Electrically Controlled Birefringence (ECB) and It can be used in combination.

As a viewing angle expanding film for TN mode, Japanese Printing Society 36, No. 3 (1999) p40-44, Monthly Display August issue (2002) p20-24, Japanese Patent Laid-Open No. 4-229828, Japanese Laid-Open Patent Publication WV films (manufactured by Fuji Photographic Film) described in JP-A-6-75115, JP-A-6-214116, JP-A-8-50206 and the like are preferably used in combination.

The preferable structure of the viewing angle magnification film for TN mode has an orientation layer and an optically anisotropic layer in this order on the transparent polymer film mentioned above. Although the viewing angle magnification film may be bonded to the polarizing plate through the pressure-sensitive adhesive, as described in SID '00 Dig., P551 (2000), it is particularly preferable in view of thinness that it is also used as one of the protective films of the polarizer.

The alignment layer can be formed by means such as rubbing treatment of an organic compound (preferably a polymer), evaporation of an inorganic compound, formation of a layer having microgroups. Moreover, although the orientation layer which generate | occur | produces an orientation function by provision of an electric field, provision of a magnetic field, or light irradiation is known, the orientation layer formed by the rubbing process of a polymer is especially preferable. The rubbing treatment is preferably carried out by rubbing the surface of the polymer layer several times in a predetermined direction of paper or cloth. It is preferable that the absorption axis direction of a polarizer and a rubbing direction are substantially parallel. As a kind of polymer used for an orientation layer, the polymer etc. which have a polymerizable group of polyimide, polyvinyl alcohol, Unexamined-Japanese-Patent No. 9-152509, etc. can be used preferably. It is preferable that it is 0.01-5 micrometers, and, as for the thickness of an orientation layer, it is more preferable that it is 0.05-2 micrometers.

It is preferable that an optically anisotropic layer contains a liquid crystalline compound. It is particularly preferable that the liquid crystalline compound used in the present invention has a discotic compound (discotic liquid crystal). The discotic liquid crystal molecule has a disk-like core portion like the triphenylene derivative of the following D-1, and has a structure in which side chains extend radially therefrom. In addition, in order to impart time-lapse stability, it is also preferable to further introduce a group that reacts with heat, light, or the like. Preferable examples of the discotic liquid crystal are described in Japanese Patent Laid-Open No. 8-50206.

Triphenylene Derivative D-1

[Chemical Formula 13]

In the vicinity of the alignment layer, the discotic liquid crystal molecules are oriented substantially parallel to the film plane with a pretilt angle in the rubbing direction, and the discotic liquid crystal molecules are aligned in a form close to the plane perpendicular to the plane on the opposite air surface side. The entire discotic liquid crystal layer has a hybrid orientation, and by this layer structure, the viewing angle enlargement of the TFT-LCD in the TN mode can be realized.

The optically anisotropic layer is generally applied to an alignment layer with a solution of a discotic compound and other compounds (for example, a polymerizable monomer, a photopolymerization initiator) in a solvent, dried, and then up to a discotic nematic phase formation temperature. After heating, it superimposes by irradiation of UV light etc., and is obtained by cooling again. As a discotic nematic liquid crystal phase-solid-state transition temperature of the discotic liquid crystalline compound used for this invention, 70-300 degreeC is preferable and especially 70-170 degreeC is preferable.

In addition, as a compound other than the discotic compound added to the said optically anisotropic layer, it has compatibility with a discotic compound, and unless the change of the preferable inclination angle is provided to a liquid crystalline discotic compound, or an orientation is not impaired, Compounds can also be used. Among these, additives for orientation control on the air interface side such as a polymerizable monomer (eg, a compound having a vinyl group, a vinyloxy group, an acryloyl group and a methacryloyl group) and a fluorine-containing triazine compound are cellulose acylate and cellulose acyl. And polymers such as late propionate, hydroxypropyl cellulose and cellulose acylate butyrate. These compounds are generally used in an amount of 0.1 to 50 mass%, preferably 0.1 to 30 mass%, based on the discotic compound.

It is preferable that it is 0.1-10 micrometers, and, as for the thickness of an optically anisotropic layer, it is more preferable that it is 0.5-5 micrometers.

A preferred embodiment of the viewing angle expanding film comprises a cellulose acylate film as a transparent base film, an alignment layer formed thereon, and an optically anisotropic layer composed of discotic liquid crystals formed on the alignment layer, wherein the optically anisotropic layer is UV light. It is bridge | crosslinked by irradiation.

In addition to the above, in the case of combining the viewing angle expanding film and the polarizing plate of the present invention, for example, as described in Japanese Patent Application Laid-Open No. 07-198942, the optical axis has an optical axis in a direction crossing the plate and has anisotropy in birefringence. It is also preferable to laminate the retardation film to be shown or to make the dimensional change rate of the protective film and the optically anisotropic layer substantially equal as described in JP-A-2002-258052. Further, as described in Japanese Patent Application Laid-Open No. 2000-258632, the moisture content of the polarizing plate bonded to the viewing angle magnification film is set to 2.4% or less, or as described in Japanese Patent Application Laid-Open No. 2000-267839. It is also preferable to set the contact angle with water on the surface to 70 degrees or less.

The viewing angle magnification film for an IPS mode liquid crystal cell is used for optical compensation of liquid crystal molecules oriented parallel to the substrate surface and for improving viewing angle characteristics of orthogonal transmittance of a polarizing plate in black display in an electric field-free state. In the IPS mode, the black display is performed in the state where no electric field is applied, and the transmission axes of the upper and lower pairs of polarizing plates are perpendicular to each other. However, when obliquely observed, the crossing angle of the transmission axis is not 90 degrees, leakage light is generated, and contrast is lowered. When using the polarizing plate of this invention for an IPS mode liquid crystal cell, in-plane retardation as described in Unexamined-Japanese-Patent No. 10-54982 is close to 0, and has retardation in thickness direction, in order to reduce leakage light. It is preferably used in combination with the viewing angle magnifying film.

The viewing angle magnification film for liquid crystal cells of the OCB mode is used to perform optical compensation of the liquid crystal layer vertically aligned at the center of the liquid crystal layer by the application of an electric field, obliquely aligned near the substrate interface, and to improve the viewing angle characteristics of the black display. When using the polarizing plate of this invention for an OCB mode liquid crystal cell, it uses suitably in combination with the viewing angle magnification film which hybrid-aligned the disk-shaped liquid crystalline compound as described in US Patent 5805253.

The viewing angle magnification film for the liquid crystal cell of VA mode improves the viewing angle characteristic of the black display of the liquid crystal molecule perpendicularly aligned with respect to the board | substrate surface in the absence of an electric field. Such a viewing angle expanding film is a film having an in-plane retardation close to zero and having a retardation in the thickness direction as described in Patent No. 2866372, or a film in which discotic compounds are arranged in parallel to a substrate. Used in combination with a film in which a stretched film having an in-plane retardation value is laminated so that the slow axis is orthogonal, or a film made of a rod-like compound such as liquid crystal molecules is laminated in order to prevent deterioration of orthogonal transmittance in the oblique direction of the polarizing plate. do.

(2) λ / 4 plate

The polarizing plate of the present invention can be used as a circularly polarizing plate laminated with a λ / 4 plate. The circularly polarizing plate has a function of converting incident light into circularly polarized light, and is preferably used for a semi-transmissive liquid crystal display device such as a reflective liquid crystal display device, an ECB mode, or an organic EL element.

5㎚ 인 것이 더욱 바람직하고, Re590-Re450

10㎚ 인 것이 특히 바람직하다. It is preferable that the λ / 4 plate used in the present invention is a retardation film having a retardation (Re) of approximately 1/4 of the wavelength in the visible light wavelength range in order to obtain approximately complete circularly polarized light in the visible light wavelength range. . The term "retardation of approximately 1/4 in the wavelength range of visible light" means that the longer the wavelength is, the longer the retardation is at the wavelength of 400 to 700 nm, and the retardation value (Re450) measured at the wavelength of 450 nm is 80 to 125 nm. The range which satisfies the relationship whose retardation value Re590 measured at 590 nm is 120-160 nm is shown. Re590-Re450

More preferably, it is 5 nm, Re590-Re450

It is especially preferable that it is 10 nm.

The λ / 4 plate used in the present invention is not particularly limited as long as the above conditions are satisfied. For example, JP-A-5-27118, JP-A-10-68816, JP-A-10. (Lambda) / 4 board which laminated | stacked the some polymer film of Unexamined-90521, (lambda) / 4 board which extended | stretched one polymer film of WO00 / 65384, WO00 / 26705, Unexamined-Japanese-Patent No. 2000-284126 A well-known (lambda) / 4 board, such as (lambda) / 4 board which formed at least 1 or more optically anisotropic layers on the polymer film of Unexamined-Japanese-Patent No. 2002-31717, can be used. In addition, the direction of the slow axis of a polymer film, and the orientation direction of an optically anisotropic layer can be arrange | positioned in arbitrary directions according to a liquid crystal cell.

In the circular polarizing plate, the slow axis of the λ / 4 plate and the transmission axis of the polarizer may cross at an arbitrary angle, but are preferably crossed in the range of 45 ° ± 20 °. However, the slow axis of the λ / 4 plate and the transmission axis of the polarizer may cross each other in the ranges other than the above.

When the λ / 4 plate is formed by laminating the λ / 4 plate and the λ / 2 plate, as described in Patent No. 3236304 and Japanese Patent Laid-Open Publication No. Hei 10-68816, the λ / 4 plate and λ / It is preferable to join so that the angle which the in-plane slow axis of a 2nd plate and the transmission axis of a polarizing plate make may become 75 degrees and 15 degrees substantially.

(3) Antireflection Film                     

The polarizing plate of the present invention can be used by bonding with an antireflection film. As the antireflection film, any one of a film having a reflectance of about 1.5% that provides only a single layer of low refractive index material such as a fluorine-based polymer or a film having a reflectance of 1% or less using multilayer interference of a thin film can be used. In this invention, the structure which laminated | stacked the low refractive index layer and the at least 1 layer (namely, the high refractive index layer, the medium refractive index layer) which has a refractive index higher than the low refractive index layer on a transparent support body is used preferably. In addition, antireflection films described in Nitto Kibo, vol. 38, No. 1, 2000, May, pages 26 to 28, and Japanese Unexamined Patent Publication No. 2002-301783 can also be preferably used.

The refractive index of each layer satisfies the following relationship.

Refractive index of the high refractive index layer> refractive index of the medium refractive index layer> refractive index of the transparent support> refractive index of the low refractive index layer

As a transparent support body used for an antireflection film, the transparent polymer film used for the protective film of the polarizing layer mentioned above can be used preferably.

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

As a fluorine-containing compound, for example, Unexamined-Japanese-Patent No. 9-222503 Paragraph No. [0018]-[0026], 11-38202 Paragraph No. [0019]-[0030], Unexamined-Japanese-Patent No. 2001-40284 The compounds described in paragraphs [0027] to [0028], JP 2000-284102 and the like can be preferably used.

Although the silicon-containing compound is preferably a compound having a polysiloxane structure, reactive silicones (e.g., cyraplane (manufactured by Chisso Co., Ltd.) or polysiloxanes containing silanol groups at both ends (Japanese Patent Laid-Open No. 11-258403), etc.) are preferable. An organometallic compound such as a silane coupling agent and a fluorine-containing hydrocarbon group-containing silane coupling agent may be cured by a condensation reaction in the presence of a catalyst (JP-A-58-142958, 58-147483). And compounds described in Japanese Patent Application Laid-Open No. 58-147484, Japanese Patent Laid-Open Nos. 9-157582, 11-106704, Japanese Laid-Open Patent Publication No. 2000-117902, 2001-48590, 2002-53804, and the like.

In the low refractive index layer, as an additive other than the above, a low refractive index inorganic compound having a primary particle average diameter of 1 to 150 nm, such as filler (for example, silicon dioxide (silica) and fluorine-containing particles (magnesium fluoride, calcium fluoride, barium fluoride)) , Organic fine particles described in paragraphs [0020] to [0038] of JP-A-11-3820), silane coupling agents, lubricants, surfactants, and the like can also be preferably carried out.

Although the low refractive index layer may be formed by a gas phase method (vacuum deposition method, sputtering method, ion plating method, plasma CVD method, etc.), it is preferable to form by a coating method from the point that it can manufacture at low cost. As the coating method, a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coat or a microgravure method can be preferably used.

It is preferable that the film thickness of a low refractive index layer is 30-200 nm, It is more preferable that it is 50-150 nm, It is most preferable that it is 60-120 nm.

It is preferable that the medium refractive index layer and the high refractive index layer have a structure in which inorganic particles ultrafine particles having a high refractive index having an average particle diameter of 100 nm or less are dispersed in a matrix material. As the high refractive index inorganic compound fine particles, inorganic compounds having a refractive index of 1.65 or more, for example, oxides such as Ti, Zn, Sb, Sn, Zr, Ce, Ta, La, In, composite oxides containing these metal atoms, etc. are preferable. Can be used.

Such ultra-fine particles are treated with a surface treatment agent (such as a silane coupling agent: Japanese Patent Laid-Open No. 11-295503, Japanese Patent Laid-Open No. 11-153703, Japanese Patent Laid-Open No. 2000-9908, an anionic compound or an organic metal coupling agent). : Japanese Laid-Open Patent Publication No. 2001-310432, etc.), a core shell structure having high refractive index particles as a core (Japanese Laid-Open Patent Publication No. 2001-166104, etc.), or using a specific dispersant in combination (for example, 11-153703, Patent No. US6210858B1, Japanese Laid-Open Patent Publication No. 2002-2776069 and the like).

As the matrix material, conventionally known thermoplastic resins, curable resin coatings, and the like can be used, but the polyfunctionality described in JP 2000-47004, 2001-315242, 2001-31871, 2001-296401, and the like. The curable film obtained from a material and the metal alkoxide composition of Unexamined-Japanese-Patent No. 2001-293818 etc. can also be used.

It is preferable that the refractive index of a high refractive index layer is 1.70-2.20. It is preferable that it is 5 nm-10 micrometers, and, as for the thickness of a high refractive index layer, it is more preferable that it is 10 nm-1 micrometer.                     

The refractive index of the medium 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. It is preferable that the refractive index of a medium refractive index layer is 1.50-1.70.

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

(4) brightness enhancement film

The polarizing plate of this invention can be used in combination with a brightness improving film. The brightness enhancement film has a separation function of circularly polarized light or linearly polarized light, and is disposed between the polarizing plate and the backlight, and one circularly polarized light or linearly polarized light is reflected back or backscattered on the backlight side. Since the re-reflected light from the backlight portion is partially transmitted when the polarization state is changed and partially reenters the luminance enhancement film and the polarizing plate, the light utilization is improved by repeating this process, and the front luminance is about 1.4 times. Is improved. Anisotropic reflection methods and anisotropic scattering methods are known as brightness enhancement films, and both can be combined with the polarizing plate of the present invention.

In the anisotropic reflection method, a uniaxially stretched film and an unstretched film are laminated in multiple layers, and a brightness enhancement film having anisotropy of reflectance and transmittance is known by increasing the refractive index difference in the stretching direction. The respective specifications of WO95 / 17691, WO95 / 17692, and WO95 / 17699) and the cholesteric liquid crystal system (European Patent 606940A2 specification, Japanese Unexamined Patent Publication No. 8-271731) are known. DBEF-E, DBEF-D, DBEF-M (all manufactured by 3M Co., Ltd.) and NIPOCS (Nitto Electric Co., Ltd.) for cholesteric liquid crystal type ) Is preferably used in the present invention. NIPOCS can be found in Nitto Kibo, vol.38, No.1, 2000, May, pages 19-21.

In addition, in the present invention, each of the specifications of WO97 / 32223, WO97 / 32224, WO97 / 32225, WO97 / 32226, and Japanese Patent Application Laid-Open Nos. Hei 9-274108 and 11-174231 has been described. It is also preferable to use it in combination with an anisotropic scattering type luminance enhancement film obtained by mixing the intrinsic birefringent polymer and the negative intrinsic birefringent polymer. As an anisotropic scattering type brightness enhancement film, DRPF-H (made by 3M) is preferable.

It is preferable to use the polarizing plate and brightness improvement film of this invention in the form bonded together via the adhesive, or integrally which made one of the protective films of a polarizing plate into a brightness improvement film.

(5) other functional optical films

The polarizing plate of the present invention may further be used in combination with a functional optical film in which a hard coat layer, a front scattering layer, an antiglare (antiglare) layer, a gas barrier layer, an active layer, an antistatic layer, an undercoat or a protective layer are formed. Do. It is also preferable to use these functional layers in combination with each other and in the same layer as the above-described antireflection layer, optically anisotropic layer and the like.                     

(5-1) Hard Coat Layer

In order to impart mechanical strength such as scratch resistance, the polarizing plate of the present invention is preferably combined with a functional optical film formed on the surface of the transparent support. In the case where the hard coat layer is applied to the above-described antireflection film and used, the hard coat layer is preferably formed between the transparent support and the high refractive index layer.

The hard coat layer is preferably formed by crosslinking or polymerization of the curable compound by light and / or heat. As a curable functional group, a photopolymerizable functional group is preferable, and, as for the organometallic compound containing a hydrolysable functional group, an organic alkoxy silyl compound is preferable. As a specific structural composition of a hard-coat layer, the thing of Unexamined-Japanese-Patent No. 2002-144913, 2000-9908, WO0 / 46617, etc. can be used preferably, for example.

It is preferable that the film thickness of a hard-coat layer is 0.2-100 micrometers.

In the pencil hardness test according to JIS K 5400, the strength of the hard coat layer is preferably at least H, more preferably at least 2H, and most preferably at least 3H. In the taper test according to JIS K5400, the smaller the amount of wear of the test pieces before and after the test, the better.

As the material for forming the hard coat layer, a compound containing an ethylenically unsaturated group and 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 triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacryl Polyacrylates of polyols such as acrylate and dipentaerythritol hexaacrylate; Epoxy acrylates such as diacrylate of bisphenol A diglycidyl ether and diacrylate of hexanediol diglycidyl ether; Urethane acrylate obtained by reaction of hydroxyl-containing acrylates, such as polyisocyanate and hydroxyethyl acrylate, is mentioned as a preferable compound. In addition, commercially available compounds include EB-600, EB-40, EB-140, EB-1150, EB-1290K, IRR214, EB-2220, TMPTA, TMPTMA (above, manufactured by Daicel UPSI Co., Ltd.), UV- 6300 and UV-1700B (above, Nippon Synthetic Chemical Co., Ltd. product) etc. are mentioned.

Preferable examples of the compound containing a ring-opening polymerizable group include ethylene glycol diglycidyl ether, bisphenol A diglycidyl ether, trimethylol ethane triglycidyl ether, and trimethylolpropane triglycidyl as glycidyl ethers. Ether, glycerol triglycidyl ether, triglycidyl trishydroxyethyl isocyanurate, sorbitol tetraglycidyl ether, pentaerythritol tetraglycidyl ether, polyglycidyl ether of cresol novolac resin, phenol novolak resin As an alicyclic epoxy, such as polyglycidyl ether of Ceroxide 2021P, Ceroxide 2081, Eporide GT-301, Eporide GT-401, EHPE3150CE (above Daicel Chemical Industries Ltd. make), phenol novolak resin Examples of the oxetanes such as polycyclohexyl epoxy methyl ether of OXT-121, OXT-221, OX-SQ, PNOX-1009 (above, Toa Synthetic Co., Ltd.), etc. are mentioned. In addition, the polymer of glycidyl (meth) acrylate or the copolymer with the monomer copolymerizable with glycidyl (meth) acrylate can also be used for a hard-coat layer.

The hard coat layer includes oxide fine particles such as silicon, titanium, zirconium, aluminum, polyethylene, polystyrene, to reduce hardening shrinkage of the hard coat layer, to improve adhesion to the substrate, and to reduce curl of the hard coat processed article of the present invention. It is also preferable to add crosslinked fine particles such as crosslinked particles such as poly (meth) acrylic acid esters and polydimethylsiloxane, and organic fine particles such as crosslinked rubber fine particles such as SBR and NBR. It is preferable that the average particle diameters of these crosslinked microparticles | fine-particles are 1 nm-20000 nm. In addition, the shape of crosslinked microparticles | fine-particles can be used without a restriction | limiting in particular, such as spherical shape, rod shape, needle shape, and plate shape. It is preferable that it is 60 volume% or less of the hard coat layer after hardening, and, as for the addition amount of microparticles | fine-particles, 40 volume% or less is more preferable.

In the case of adding the inorganic fine particles described above, since affinity with the binder polymer is generally poor, it contains metals such as silicon, aluminum and titanium, and further contains alkoxide groups, carboxylic acid groups, sulfonic acid groups, phosphonic acid groups and the like. Surface treatment using a surface treating agent having a functional group of is also preferably performed.

It is preferable to harden the hard coat layer using heat or an active energy ray, and in particular, it is more preferable to use active energy rays such as radiation, gamma ray, alpha ray, electron ray, and ultraviolet ray. Particular preference is given to using ultraviolet light. In the case of curing by heat, considering the heat resistance of the plastic itself, the heating temperature is preferably 140 ° C. or lower, and more preferably 100 ° C. or lower.

(5-2) Forward Scattering Layer                     

The front scattering layer is used to improve the viewing angle characteristics (color and luminance distribution) in the up, down, left, and right directions when the polarizing plate of the present invention is applied to a liquid crystal display device. In this invention, the structure which binder disperse | distributed the microparticles | fine-particles with which refractive index differs is preferable, for example, Unexamined-Japanese-Patent No. 11-38208 which specified the forward scattering coefficient, Unexamined-Japanese-Patent which made the relative refractive index of transparent resin and microparticles into a specific range. The structure of Unexamined-Japanese-Patent No. 2000-199809, Unexamined-Japanese-Patent No. 2002-107512 which prescribed | regulated haze value 40% or more can be used. In addition, in order to control the viewing angle characteristic of a haze, it can also perform using the polarizing plate of this invention in combination with "Lumisti" described in the technical report "optical functional film" pages 31-39 of Sumitomo Chemical.

(5-3) Antiglare Layer

Antiglare (anti-glare) layers are 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. Usually, an antiglare layer is formed on the protective film on the air side of a polarizing plate. The haze of the optical film having an antiglare function is preferably 3 to 30%, more preferably 5 to 20%, and most preferably 7 to 20%.

The method of forming the unevenness on the surface of the film is, for example, a method of forming unevenness on the surface of the film by adding fine particles (for example, Japanese Patent Application Laid-Open No. 2000-271878, etc.), and a small amount of relatively large particles (particle diameter of 0.05 to 2 µm) (0.1 To 50 mass%) to form a surface asperity film (for example, Japanese Patent Application Laid-Open No. 2000-281410, 2000-95893, 2001-100004, 2001-281407, etc.), and physically irregularities on the film surface. A method of transferring a shape (for example, described in JP-A-63-278839, JP-A-11-183710, JP-A-2000-275401, etc.) as the embossing method can be preferably used. .

These functional layers can be formed and used on either one side or both sides of a polarizer side and an opposite surface to a polarizer side.

5. Liquid Crystal Display Using Polarizer

Next, a liquid crystal display device in which the polarizing plate of the present invention is used will be described.

2 is an example of a liquid crystal display device in which the polarizing plate of the present invention is used.

The liquid crystal display device shown in FIG. 2 has liquid crystal cells 15-19, and the upper polarizing plate 11 and the lower polarizing plate 22 which pinched | interposed the liquid crystal cells 15-19. Although the polarizing plate is sandwiched by a polarizer and a pair of transparent protective films, it is shown as an integrated polarizing plate in FIG. 2, and the detailed structure is abbreviate | omitted. The liquid crystal cell consists of a liquid crystal layer formed of the upper substrate 15 and the lower substrate 18 and the liquid crystal molecules 17 sandwiched therebetween. The liquid crystal cell is a difference between the alignment states of the liquid crystal molecules that perform ON / OFF display. TN (Twisted Nematic), IPS (In-Plane Switching), OCB (Optically Compensatory Bend), VA (Vertically Aligned), ECB (Electrically Controlled) Although classified as a display mode such as Birefringence, the polarizing plate of the present invention can be used in any display mode irrespective of transmission and reflection type.

An alignment film (not shown) is formed on a surface (hereinafter sometimes referred to as "inner surface") in contact with the liquid crystal molecules 17 of the substrates 15 and 18, and an electric field is applied by a rubbing treatment or the like performed on the alignment film. The orientation of the liquid crystal molecules 17 in the unapplied state or the low applied state is controlled. Moreover, the transparent electrodes (not shown) which can apply an electric field to the liquid crystal layer which consists of liquid crystal molecules 17 are formed in the inner surface of the board | substrates 15 and 18. As shown in FIG.

The rubbing direction in the TN mode is performed in the direction perpendicular to each other on the upper and lower substrates, and the magnitude of the tilt angle can be controlled by the strength, the number of rubbings, and the like. The alignment film is formed by applying a polyimide film and baking it. The magnitude of the twist angle (twist angle) of the liquid crystal layer is determined by the crossing angle of the rubbing direction of the upper and lower substrates and the chiral agent added to the liquid crystal material. In this case, a chiral agent having a pitch of about 60 μm was added so that the twist angle was 90 °.

The twist angle is set at 90 ° (85 to 95 °) in the case of a liquid crystal display device for a notebook, a personal computer monitor or a television, and 0 to 70 ° when used as a reflective display device such as a mobile phone. . In addition, in the IPS mode or the ECB mode, the twist angle is 0 degrees. In the IPS mode, the electrode is arranged only on the lower substrate 8, and an electric field parallel to the substrate surface is applied. In the OCB mode, there is no twist angle, the tilt angle becomes large, and in the VA mode, the liquid crystal molecules 7 are oriented perpendicular to the upper and lower substrates.

Here, the magnitude of the product Δnd of the thickness d of the liquid crystal layer and the refractive index anisotropy Δn changes the brightness at the time of white display. For this reason, the range is set for each display mode to obtain the maximum brightness.                     

The crossing angle between the absorption axis 12 of the upper polarizing plate 11 and the absorption axis 23 of the lower polarizing plate 22 is generally laminated at approximately orthogonal heights to obtain high contrast. The crossing angle between the absorption axis 12 of the upper polarizing plate 11 of the liquid crystal cell and the rubbing direction of the upper substrate 15 varies depending on the liquid crystal display mode, but is generally set parallel or vertical in the TN and IPS modes. It is often set to 45 ° in OCB and ECB modes. However, the optimum value is different in each display mode for the adjustment of the color tone and the viewing angle of the display color, but is not limited to this range.

The liquid crystal display device in which the polarizing plate of the present invention is used is not limited to the configuration of FIG. 2 and may include other members. For example, a color filter may be disposed between the liquid crystal cell and the polarizer. In addition, the above-mentioned viewing angle expanding films 13 and 20 may be disposed separately between the liquid crystal cell and the polarizing plate. The polarizing plates 11 and 23 and the viewing angle magnification films 13 and 20 may be arranged in a laminated form bonded with an adhesive, or may be arranged as a so-called integrated elliptical polarizing plate using one side of the liquid crystal cell side protective film for expanding the viewing angle.

Moreover, when using as a transmission type, the backlight which uses a cold cathode or a hot cathode fluorescent tube, or a light emitting diode, a field emission element, an electroluminescent element as a light source can be arrange | positioned at the back surface. In addition, the liquid crystal display device in which the polarizing plate of the present invention is used may be a reflection type, and in such a case, only one polarizing plate may be disposed on the observer's side, and may be disposed on the rear surface of the liquid crystal cell or the inner surface of the lower substrate of the liquid crystal cell. Install a reflective film. Of course, the front light using the light source may be formed on the liquid crystal cell observation side.                     

[Example]

The present invention will be described in detail with reference to the following Examples.

Example 1

(Preparation of cellulose acylate solution)

The following composition was thrown into the mixing tank, it stirred, each component was melt | dissolved, and the cellulose acylate solution A was prepared.

(Composition of Cellulose Acylate Solution A>

Acyl substitution degree 2.4, butyrylation degree 1.7, acetylation degree of 0.7

100.0 parts by mass of cellulose acylate

Hydrophobizer C-7 7.0 parts by mass

Hydrophobizer C-10 7.0 parts by mass

Methylene chloride (first solvent) 307.0 parts by mass

93.0 parts by mass of ethanol (second solvent)

(Preparation of Matte Solution)

The following composition was put into the disperser, and it stirred and disperse | distributed and melt | dissolved each component, and the mat agent solution was prepared.

<Mat agent solution composition>

Silica particles with an average particle diameter of 16 nm

(2.0 parts by mass of AEROSIL R972, Nippon Aerosol Co., Ltd.)

Methylene chloride (first solvent) 72.4 parts by mass                     

10.8 parts by mass of methanol (second solvent)

Cellulose acylate solution A 10.3 parts by mass

(Preparation of Ultraviolet Absorber Solution)

The following composition was put into the mixing tank, stirred while heating to dissolve each component, and the cellulose acylate solution was prepared.

<Ultraviolet absorber solution composition>

40 parts by mass of the following ultraviolet absorber C

Methylene chloride (first solvent) 58.3 parts by mass

8.7 parts by mass of ethanol (second solvent)

Cellulose Acelate Solution A 12.8 parts by mass

UV absorber C

[Formula 14]

(Manufacture of cellulose acylate film 1)

94.6 parts by mass of the cellulose acylate solution A, 1.3 parts by mass of the matte solution and 2.1 parts by mass of the ultraviolet absorber solution were filtered, and then mixed, and the mixture was cast using a band softener. The film was peeled from the band at an I / O ratio of 1.5 of the residual solvent, and the film was transversely stretched at a stretch ratio of 4% using a tenter at 130 ° C., and the width after stretching was maintained at 140 ° C. for 30 seconds. Then, the clip was removed and dried at 140 degreeC for 40 minutes, and the cellulose acylate film 1 was produced. The residual solvent amount of the completed cellulose acylate film was 0.2%, and the film thickness was 80 µm.

Cellulose acylate film in the same manner except for changing the kind of cellulose acylate and the kind of hydrophobization agent, the addition amount, the solvent composition of the cellulose acylate solution A, and the I / O ratio of the residual solvent at the time of peeling to the content of Table 1. 2-18 were produced.

[Example 2]

<Measurement of Retardation>

Re and Rth were measured in the environment of 25 degreeC 10%, 25 degreeC 60%, 25 degreeC 80% by the following method.

The in-plane retardation Re (0) was measured using an automatic birefringence meter (KOBRA-21ADH, manufactured by OW Clock Co., Ltd.). In addition, the retardation Re (40) and Re (-40) were measured by turning 40 degrees and -40 degrees with the in-plane slow axis as the gate axis. Using the film thickness and the refractive index nx in the slow axis direction as parameters, the refractive index ny in the fast axis direction and the refractive index nz in the thickness direction are calculated to fit these measured values Re (0), Re (40) and Re (-40). It calculated | required and the Rth retardation value was determined. The measurement wavelength was 590 nm.

<Measurement of dimension change rate>

The film was humidified for 4 hours in a room moistened at a temperature of 25 ° C. and a relative humidity of 60%, and then each hole in the lengthwise direction was drilled with a pin gauge, and the dimension (L1) was measured with a pin gauge. Next, after storing for 24 hours in a 90 degreeC constant temperature layer, it humidified for 4 hours in the room humidified at the temperature of 25 degreeC and 60% of relative humidity again, and measured the dimension (L2) by pin gauge. The rate of dimensional change was calculated by the following formula.

Dimensional rate of change (%) = [(L2-L1) / L1] × 100

<Measurement of moisture permeability>

According to the method described in JIS Z0208, the water vapor transmission rate of each sample was measured. The temperature and humidity conditions tested were 25 ℃ 90% RH.

<Measurement of moisture content>

After humidifying for 24 hours in an environment of 25 ° C and 80% RH, the equilibrium moisture content was measured by AQ-2000 Cul fischer moisture measuring apparatus manufactured by Hiranuma Industries.

<Measurement of elastic modulus>

The sample was humidified for 24 hours in 25 degreeC 60% RH environment, and the elasticity modulus was measured in accordance with the method of JISK7127. Tensile tester manufactured by A & D Co., Ltd. was used for the tensile tester. The test piece was 50 mm x 10 mm, and the chuck distance was 30 mm, and the test speed was 30 mm / min.

The above result is shown in Table 2.                     

The result shown in Table 2 shows that the cellulose acylate film of this invention is preferable because it is small in humidity dependence of retardation, and also excellent in dimensional stability.

[Example 3]                     

(Saponification)

The cellulose acylate film 1 was immersed in a 1.5% sodium hydroxide aqueous solution at 55 ° C for 2 minutes. It wash | cleaned in the water washing bath of room temperature, and it neutralized using 0.1 sulfuric acid at 30 degreeC. It wash | cleaned again in the water washing bath of room temperature, and dried again by the warm air of 100 degreeC. In this manner, the surface of the cellulose acylate film was saponified.

(Manufacture of Polarizing Plate)

Iodine was adsorbed on the stretched polyvinyl alcohol film to prepare a polarizing film.

Next, the transparent support side of the saponified cellulose acylate film was adhere | attached on one side of a polarizing film using the polyvinyl alcohol-type adhesive agent. It was arrange | positioned so that the slow axis of a saponified cellulose acylate film and the transmission axis of a polarizing film may become parallel.

A commercially available cellulose acylate film (Fujitack TD80UF, manufactured by Fuji Photo Film Co., Ltd.) was saponified in the same manner as described above, and adhered to the opposite side of the polarizing film using a polyvinyl alcohol-based adhesive. In this way, the polarizing plate 1 was manufactured.

(Manufacture of polarizing plate with retardation film)

A norbornene-based resin film (manufactured by JSR, Atom) having a thickness of 100 μm was stretched at 175 ° C. with a tenter stretching machine to produce a retardation film having a refractive index characteristic of nx> ny> nz and having Re of 40 nm and Rth of 30 nm. And it adhere | attached on the cellulose acylate film 1 side of the polarizing plate 1 manufactured using the adhesive.

Example 4                     

The norbornene-based resin film was removed from the polarizer on the observer side formed in the 22-inch liquid crystal display device (manufactured by Sharp Co., Ltd.) using the VA-type liquid crystal cell. It adhere | attached on the observer side through an adhesive so that it might become a liquid crystal cell side. It was arrange | positioned so that the transmission axis of the polarizing plate of an observer side, and the transmission axis of the polarizing plate of a backlight side may orthogonally cross.

It was found that the polarizing plate of the present invention is preferable because of its small dependence and low change in the use environment humidity of contrast and color viewing angle.

[Example 5]

(Preparation of cellulose acylate film solution B)

The following composition was thrown into the mixing tank, it stirred, heating, each component was melt | dissolved and the cellulose acylate solution B was prepared.

<Cellulose Acylate Solution B Composition>

Of acyl substitution degree 2.4, butyrylation degree 1.4, and acetylation degree 1.0

100 parts by mass of cellulose acylate

Hydrophobization agent A-2 7.8 parts by mass

Hydrophobizer A-5 3.9 parts by mass

280 parts by mass of methylene chloride (first solvent)

64 parts by mass of methanol (second solvent)

21 parts by mass of 1-butanol

The following composition was thrown into another mixing tank, it stirred while heating, each component was melt | dissolved, and the ultraviolet absorber solution C was prepared.

<Ultraviolet absorber solution C composition>

80 parts by mass of methylene chloride

20 parts by mass of methanol

2 parts by mass of the following ultraviolet absorbent (A)

4 parts by mass of the following ultraviolet absorber (B)

[Formula 15]

(Manufacture of cellulose acylate film 21)

40 mass parts of hydrophobization agent solutions C were added to 474 mass parts of cellulose acylate solution B, and it fully stirred, and dope was prepared. The dope was cast on a drum cooled from 0 ° C. to 0 ° C. The residual solvent was separated at an I / O ratio of 1.1, and both ends in the width direction of the film were fixed with a pin tenter (the pin tenter described in FIG. 3 of JP-A-4-1009), and the solvent content was 3 to 5 mass%. In the phosphorus state, it dried for 10 minutes at 140 degreeC, maintaining the space | interval which the elongation of a horizontal direction (direction perpendicular | vertical to a machine direction) becomes 3%. Then, it conveyed between the rolls of the heat processing apparatus, it dried again at 150 degreeC for 20 minutes, and produced the cellulose acylate film 21 of thickness 80micrometer.

<Production of Cellulose Acylate Films 22 to 26>

In the manufacture of the cellulose acylate film 21, cellulose acylate films 22 to 26 were produced in the same manner as in the cellulose acylate film 21 except that the cellulose acylate and the hydrophobizing agent were changed to those in Table 3.

About the produced cellulose acylate films 22-26, the humidity dependency of the optical characteristic was measured by the method similar to Example 2. The results are shown in Table 4.

From the result shown in Table 4, it is understood that the cellulose acylate film of the present invention is preferable because Re and Rth are small and the humidity dependency is small.

[Example 6]

(Evaluation of IPS LCD Display)

Using the cellulose acylate film 1 of the present invention prepared in Example 1, a uniaxially stretched optical compensation film was bonded to the polarizing plate produced in the same manner as in Example 3 to give an optical compensation function. At this time, by making the slow axis of the in-plane retardation of the optical compensation film orthogonal to the transmission axis of the polarizing plate, the visual characteristics can be improved without changing the front characteristics at all. The in-plane retardation Re of the optical compensation film used was 270 nm, the retardation Rth of the thickness direction was 0 nm, and the Nz factor was 0.5.

The laminated body of the polarizing plate and the optical compensation film using the cellulose acylate film 1 of this invention manufactured as mentioned above, the liquid crystal cell of an IPS type, and it assembled and superimposed from the top in order of the polarizing plate using the cellulose acylate film 1 of this invention. One display device was manufactured. At this time, the transmission axis of the upper and lower polarizing plates was orthogonal to each other, and the transmission axis of the upper polarizing plate was parallel to the molecular long axis direction of the liquid crystal cell (that is, the slow axis of the optical compensation layer and the molecular long axis direction of the liquid crystal cell were orthogonal). The liquid crystal cell, the electrode, and the board | substrate can use what is conventionally used as IPS as it is. The orientation of the liquid crystal cell is horizontal orientation, and the liquid crystal has positive dielectric anisotropy, and those developed and marketed for IPS liquid crystal can be used. The physical properties of the liquid crystal cell were set to Δn: 0.099 of the liquid crystal, the cell gap of the liquid crystal layer: 3.0 µm, the pretilt angle: 5 degrees, and the rubbing direction: 75 degrees both above and below the substrate.

In the liquid crystal display device manufactured as described above, the optical leakage rate at the time of black display at 45 degrees in the azimuth direction and 70 degrees in the polar angle direction from the front of the apparatus was measured, and the optical produced by the cellulose acylate film of the present invention. Compensation film and polarizing plate, it can be seen that the use environment humidity dependence of the viewing angle characteristics is preferable.

According to the present invention, it is possible to provide a cellulose acylate film having a small optical anisotropy and a small change in optical characteristics due to heat and humidity.

Moreover, according to this invention, it is possible to provide the polarizing plate protective film which is excellent in processing suitability and excellent in durability, without the surface failure and performance change at the time of polarizing plate manufacture.

According to the present invention, a polarizing plate using a protective film having a small optical anisotropy and a small change in optical characteristics due to heat or humidity is used in a liquid crystal display device, so that problems such as light leakage do not occur and are displayed at a wide viewing angle. A liquid crystal display device of high quality can be provided.

Claims (23)

delete delete As a cellulose acylate film obtained by the manufacturing method which has a process which casts the cellulose acylate solution containing a cellulose acylate and a solvent on a support body, and removes the film obtained by the said casting | flow_spread from the said support body, The inorganic / organic ratio (I / O ratio) of the residual solvent in the film obtained by the said casting | flow_spread is 0.65 or more and 4 or less at the time of peeling off the said film from the said support body, The cellulose acylate film has a compound having one or more hydrogen bondable hydrogen donor groups and an octanol-water partition coefficient of 2 or more and 12 or less, Substitution degree of an acyl group is 1 or more and 2.6 or less, substitution degree of an acetyl group is 1.4 and the average carbon number of the said acyl group is 2.4 or more and 5 or less, The cellulose acylate film characterized by the above-mentioned. delete delete delete The method of claim 3, wherein The solvent contains methylene chloride and alcohol, When the sum total of the said methylene chloride and the said alcohol is 100 mass%, the ratio of the said alcohol is 10 mass% or more and 40 mass% or less, The cellulose acylate film characterized by the above-mentioned. The method of claim 3, wherein The absolute value of the in-plane retardation (Rth) of 25 ° C 60% RH is 25 nm or less, and the difference between the in-plane retardation (Rth) of 25 ° C 10% RH and the in-plane retardation (Rth) of 25 ° C 10% RH is 40nm. The cellulose acylate film characterized by the following. The method of claim 3, wherein Retardation Re in the thickness direction of 25 ° C. 60% RH is 0 nm or more and 20 nm or less, and retardation Re in the thickness direction 25 ° C. 10% RH and retardation in the thickness direction 25 ° C. 80% RH ( The difference of Re) is 20 nm or less, The cellulose acylate film characterized by the above-mentioned. The method of claim 3, wherein The water vapor transmission rate when it is left to stand in 25 degreeC 90% RH atmosphere for 24 hours is 20 g / m <2> or more and 250g / m <2> or less, The cellulose acylate film characterized by the above-mentioned. The method of claim 3, wherein Equilibrium moisture content in 25 degreeC 80% RH is 6 mass% or less, The cellulose acylate film characterized by the above-mentioned. The method of claim 3, wherein A cellulose acylate film, wherein the dimensional change rate at 90 ° C. over time is 0.5% or more and 0.5% or less. The method of claim 3, wherein The modulus of elasticity of one or more directions in a film plane is 1.0 kPa or more and 6.0 kPa or less, The cellulose acylate film characterized by the above-mentioned. A polarizing plate on which protective films are bonded to both sides of a polarizer, wherein at least one of the protective films is a cellulose acylate film according to claim 3. 15. The method of claim 14, It has an adhesive layer, The polarizing plate characterized by the above-mentioned. 15. The method of claim 14, It has an antiglare layer, The polarizing plate characterized by the above-mentioned. 15. The method of claim 14, Polarizing plate having an anti-reflection film layer. 15. The method of claim 14, It has a retardation film layer or (lambda) / 4 plate, The polarizing plate characterized by the above-mentioned. 15. The method of claim 14, It has a viewing angle magnification film layer, The polarizing plate characterized by the above-mentioned. 15. The method of claim 14, It has a brightness improving film layer, The polarizing plate characterized by the above-mentioned. A liquid crystal display device having a liquid crystal cell and a polarizing plate on both sides of the liquid crystal cell, wherein at least one polarizing plate is a polarizing plate according to claim 14. 22. The method of claim 21, And the liquid crystal cell is a VA cell liquid crystal cell. 22. The method of claim 21, And the liquid crystal cell is an IPS mode liquid crystal cell.

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