KR101308171B1 - Cellulose acylate film and method for producing same, polarizer and liquid crystal display device - Google Patents

Abstract

assignment
Providing the cellulose acylate film which wavelength dispersion is reverse dispersion, the Rth per film thickness is large, and the display when affixed to a panel after polarizing plate processing becomes uniform in surface inside, and its manufacturing method.
Solution
The total acyl substitution degree contains the cellulose acylate of 2.1-2.8, the elasticity modulus of a film conveyance direction is 3200 Mpa or more, the variation of the elasticity modulus of a film width direction is 0.5 kPa or less, and satisfy | fills following formula (1)-(3) Cellulose acylate film, characterized in that.
Equation (1) 0 ≤ ΔRe ≤ 15.0
(DELTA Re represents the value (unit: nm) which subtracted the value of in-plane retardation in wavelength 450nm from the value of retardation of the in-plane direction in wavelength 630nm.)
(2) 2 × 10 ^-3 ≤ Rth / d ≤ 6 × 10 ^-3
(In formula, Rth represents the value (unit: nm) of retardation of the film thickness direction in wavelength 550nm, d shows the film thickness (unit: nm).)
Equation (3) 1.0 ≤ E '(TD) / E' (MD) ≤ 1.43
(In formula, E '(MD) shows the elasticity modulus (unit: Mpa) of a film conveyance direction, E' (TD) shows the elastic modulus (unit: MPa) of a film width direction.)

Description

Cellulose acylate film, its manufacturing method, polarizing plate, liquid crystal display device {CELLULOSE ACYLATE FILM AND METHOD FOR PRODUCING SAME, POLARIZER AND LIQUID CRYSTAL DISPLAY DEVICE}

This invention relates to a cellulose acylate film and its manufacturing method. More specifically, a cellulose acylate film containing cellulose acylate, having a wavelength dispersion of reverse dispersion, a large Rth per film thickness, and uniformity in the surface when affixed to the panel after polarizing plate processing; and The manufacturing method is related. Moreover, it also relates to the polarizing plate and liquid crystal display device which used this cellulose acylate film.

The liquid crystal display device of the VA (Vertically Aligned) mode is attracting attention as a liquid crystal display device for television because of its high contrast and relatively high production yield. In order to enlarge the viewing angle of the liquid crystal display device of VA mode, the cellulose acylate film is conventionally used as optical films, such as an optical compensation film.

In recent years, in the optical film for VA, the film which shows the reverse dispersion property which the retardation Re of an in-plane direction increases as the wavelength becomes large from a viewpoint of improving the color taste change when observing the display from an oblique orientation is calculated | required. At the same time, it is required to increase the thickness of the retardation Rth in the thickness direction per film thickness in order to reduce the thickness of the panel and the manufacturing cost. On the other hand, with the enlargement of a liquid crystal display device, the optical film which has preferable physical property which can achieve the in-plane uniformity of a panel is calculated | required.

For example, Patent Literature 1 discloses excellent expression properties of front and film thickness direction retardation by a method of adding a retardation expression agent or a method of forming a film so as to satisfy a specific elastic modulus, and for environmental changes such as humidity. The optical film and polarizing plate with little fluctuation | variation of the retardation value by this are disclosed. The document discloses that wavelength dispersion can be controlled by stretching, and in the document example, in the solution film formation method using a material such as CAP (cellulose acetate propionate) or CAB (cellulose acetate butyrate) The example which performed biaxial stretching of extending | stretching to the film conveyance direction and the film width direction of the film which peeled in the state of 25-35 mass% of residual volatile matter is disclosed.

In addition, Patent Document 2 discloses a cellulose acylate film having good haze and planar shape by controlling a water content and an SP value by using a solvent and a cellulose acylate resin having a specific acyl substitution degree. In the document example, the example which extended | stretched the film which peeled in the state of 25-35 mass% of residual volatile matter in 10 to 50% of range in the film width direction is disclosed in the solution film forming method.

Japanese Laid-Open Patent Publication 2006-030962 Japanese Unexamined Patent Publication No. 2009-263619

However, it is difficult to attain both the development of anti-dispersibility and the improvement of Rth of the film thickness, and at present, the cost has to be sacrificed by using productivity and expensive special additives. Moreover, as a result of examining the method of adding the additive for controlling the special optical performance by this inventor, only using the conventionally known additive, the in-plane display deviation at the time of sticking to a panel after polarizing plate processing does not become uniform, Dissatisfaction proved to remain. Moreover, when the film drying conditions on the support body at the time of casting film were changed, when the composition and extending | stretching conditions which are compatible with conventionally known Rth and wavelength dispersion are employ | adopted, the in-plane display deviation at the time of affixing on a panel similarly is uniform. It also proved not to go away. Therefore, in addition to the expression of reverse dispersion and the improvement of Rth per film thickness, it was very difficult to improve the in-plane display uniformity. Therefore, it is necessary to improve film forming conditions so that film properties may be changed so that extending | stretching conditions etc. can be changed into film forming conditions different from the past, and it can improve in-plane display uniformity in addition to expression of the said optical characteristic. I thought it was.

That is, the problem to be solved by this invention is a cellulose acylate film which wavelength dispersion is reverse dispersion, the Rth per film thickness is large, and the display when affixed on a panel after polarizing plate processing becomes uniform in surface, and its manufacturing method It is to offer.

In general, it is known that the axial deviation of the optical film is improved as the draw ratio in the TD direction (the direction orthogonal to the film conveying direction, that is, the film width direction) is increased (see Patent Document 1). Therefore, as a result of the present inventor's examination of the manufacturing method described in Patent Document 1, the film obtained in the document example also includes a film which becomes counter-dispersible, but CAP (cellulose acetate propionate) or CAB (cellulose acetate butyrate) Materials such as these have a low elastic modulus and have problems in view of panel in-plane uniformity when processed into a polarizing plate. Moreover, in this document, about the manufacturing method, the detail of the preferable residual volatile matter in each of longitudinal stretch and lateral stretch, and the draw ratio in each direction at that time is not examined in particular, Even if it refers to description of the said document, Could not be improved.

Moreover, even if extending | stretching only to the TD direction described in the Example of patent document 2 was performed, and controlling the solvent residual amount and drying conditions at the time of extending | stretching, the said subject could not be solved.

Then, this inventor examined the combination of the prescription and the manufacturing method which become in-plane dispersion | variation favorable about the solution film forming film from which the kind of various additives and cellulose acylate differs. As a result, for the film expressing the expression amount and the reverse dispersion of the intended Rth, the elastic modulus in the MD direction is raised to a specific value or more to control the TD / MD ratio of the elastic modulus to be within a specific range, and the variation in the elastic modulus in the TD direction is controlled. The film which controlled so that it might become below a specific value discovered that display deviation was remarkably reduced in surface when affixing on a panel after polarizing plate processing, and came to complete this invention.

Furthermore, the present inventors have found that by adopting specific stretching conditions according to the type of cellulose acylate, it is possible to provide various cellulose acylate films that can solve the above problems by making the physical properties and optical properties compatible, and the present invention. It came to complete the manufacturing method of the film.

Specifically, the problem was solved by the following means.

[1] The total acyl substitution degree contains cellulose acylate of 2.1 to 2.8, the elastic modulus in the film conveyance direction is 3200 MPa or more, and the variation in the elastic modulus in the film width direction is 0.5 kPa or less, and the following formulas (1) to (3 Cellulose acylate film, characterized in that to satisfy).

Equation (1) 0 nm ≤ ΔRe ≤ 15.0 nm

(DELTA Re represents the value (unit: nm) which subtracted the value of in-plane retardation in wavelength 450nm from the value of retardation of the in-plane direction in wavelength 630nm.)

(2) 2 × 10 ^-3 ≤ Rth / d ≤ 6 × 10 ^-3

(In formula, Rth represents the value (unit: nm) of retardation of the film thickness direction in wavelength 550nm, d shows the film thickness (unit: nm).)

Equation (3) 1.0 ≤ E '(TD) / E' (MD) ≤ 1.43

(In formula, E '(MD) shows the elasticity modulus (unit: Mpa) of a film conveyance direction, E' (TD) shows the elastic modulus (unit: MPa) of a film width direction.)

[2] The cellulose acylate film according to [1], wherein the elastic modulus in the film conveyance direction is 3500 MPa or more.

[3] The retardation value Re in the in-plane direction at the wavelength of 590 nm and the retardation value Rth in the film thickness direction at the wavelength of 590 nm satisfy the following formula: [1] or [2]. Cellulose acylate film.

35 nm ≤ Re ≤ 80 nm, 100 nm ≤ Rth ≤ 300 nm

[4] The cellulose acylate film according to any one of [1] to [3], wherein the cellulose acylate is cellulose acetate.

[5] The cellulose acylate film according to any one of [1] to [4], which contains a polycondensation ester.

[6] The cellulose acylate film according to any one of [1] to [5], wherein the Re expression agent is contained less than 3% by mass relative to the cellulose acylate.

[7] The cellulose acylate film according to any one of [1] to [6], which contains an organic acid represented by the following General Formula (1).

In general formula (1)

XL- (R ¹ ) _n

(In the formula (1), X is the acid dissociation constant of 5.5 or less represents a substituent containing an acidic group, L is a single bond or a represents a more linking group, R ¹ is an alkyl group having 6 to 30 carbon atoms, having 6 to 30 carbon atoms It may represent an alkenyl group, a C6-C30 alkynyl group, a C6-C30 aryl group, or a C6-C30 heterocyclic group, and may have a substituent further, n is 1 when L is a single bond, and L is When these two or more coupling groups are (the valence of L-1))

[8] R ¹ in General Formula (1) represents an alkyl group having 6 to 24 carbon atoms, an alkenyl group having 6 to 24 carbon atoms, or an alkynyl group having 6 to 24 carbon atoms (however, may further have a substituent. The cellulose acylate film as described in [7] characterized by the above-mentioned.

[9] X in the general formula (1) has at least one group selected from the group consisting of at least one carboxyl group, sulfonic acid group, sulfinic acid group, phosphoric acid group, sulfonimide group and ascorbic acid group The cellulose acylate film as described in [7] or [8].

[10] The L in the general formula (1) is a single bond or a linking group obtained by combining two or more units selected from the following unit group or two or more units selected from the following unit group. ]-The cellulose acylate film according to any one of [9].

Units: -O-, -CO-, -N (R ² )-(wherein R ² represents an alkyl group having 1 to 5 carbon atoms), -OH, -CH = CH-, -CH (OH)-, -CH _2- , -SO _2- ,

[Formula 1]

[11] The organic acid represented by the general formula (1) is formed by combining one molecule of a fatty acid and one molecule of a polycarboxylic acid with one molecule of a polyhydric alcohol, and at least one unsubstituted carboxyl group derived from a polyvalent carboxylic acid. The cellulose acylate film as described in any one of [7]-[10] which has it.

[12] The cellulose acylate film according to any one of [7] to [11], wherein the organic acid represented by General Formula (1) is 200 to 1000.

[13] The cellulose acylate film according to any one of [1] to [12], wherein the cellulose acylate film has a laminated structure of two or more layers and the average total acyl substitution degree of the cellulose acylate contained in each layer is different from each other.

[14] The cellulose acylate film according to any one of [1] to [13], wherein the standard deviation (σ) of the slow axis orientation in the film width direction edge part is 0.10 or less.

[15] a step of obtaining a film by solution casting a dope containing cellulose acetate having a total acyl substitution degree of 2.1 to 2.8 on a metal support, and peeling the film from the metal support with residual volatile matter H1 satisfying the following formula (VII): The process of extending | stretching and the process of extending | stretching the peeled film to 5 to 100% in a film conveyance direction in the state of residual volatile matter H2 which satisfy | fills following formula (ii), and the residual volatile matter which satisfy | fills the peeled film below formula (i) The extending | stretching process satisfy | fills following formula (i) including the process of extending | stretching 20 to 150% in the direction orthogonal to a film conveyance direction in the state of H3, The manufacturing method of the cellulose acetate film characterized by the above-mentioned.

Formula (i) 20% ≤ H1 ≤ 60%

Formula (ii) 10% ≤ H2 ≤ 60%

Formula (VIII) 5% ≤ H3 ≤ 45%

Formula (i) (MD draw ratio + 100%) / (TD draw ratio + 100%) ≥ 0.70

(In formula, MD draw ratio shows the draw ratio (unit:%) to a film conveyance direction, TD draw ratio shows the draw ratio (unit:%) to the direction orthogonal to a film conveyance direction.)

[16] a step of solution casting of a dope containing cellulose butyrate or cellulose propionate having a total acyl substitution degree of 2.1 to 2.8 on a metal support, and obtaining the film from the metal support; The process of peeling with residual volatile matter H1 to make, the process of extending | stretching the peeled film to 20-100% in a film conveyance direction in the state of residual volatile matter H2 which satisfy | fills following formula (ii), and the peeled film are the following formula (ⅰ) In the state of residual volatile matter H3 which satisfy | fills), the process of extending | stretching 35 to 150% in the direction orthogonal to a film conveyance direction is included, The said extending | stretching process satisfies following formula (i) of the cellulose acylate film characterized by the above-mentioned. Manufacturing method.

Formula (i) 20% ≤ H1 ≤ 60%

Formula (ii) 10% ≤ H2 ≤ 60%

Formula (VIII) 5% ≤ H3 ≤ 45%

Formula (i) (MD draw ratio + 100%) / (TD draw ratio + 100%) ≥ 0.70

(In formula, MD draw ratio shows the draw ratio (unit:%) to a film conveyance direction, TD draw ratio shows the draw ratio (unit:%) to the direction orthogonal to a film conveyance direction.)

[17] The method for producing a cellulose acylate film according to [15] or [16], wherein the stretching in the film conveyance direction is performed while the tension variation is controlled in a state of less than 10 N / m.

[18] The above-mentioned dope, wherein two or more dopes having different total acyl substitution degrees of cellulose acylates are used, and each dope is co-flexible on a support. The manufacturing method of the cellulose acylate film of any one of Claims.

[19] The moving part from the peeling step to the stretching step, wherein the film passes three or more pass rolls having a wrap angle of at least 60 °, wherein the film passes at least three. The manufacturing method of a cellulose acylate film.

[20] The method for producing a cellulose acylate film according to any one of [15] to [19], wherein the pass roll includes at least one dancer.

[21] The cellulose acyl according to any one of [15] to [20], wherein the dope cast on the metal support is blown with dry air from both the back surface and the surface of the metal support. Method for producing a late film.

[22] The cellulose acylate film according to any one of [15] to [21], wherein stretching is performed in a direction orthogonal to the film conveying direction by a tenter to satisfy the following formula (i). Method of preparation.

Formula (ⅴ) W × 30 ≥ L ≥ W × 2

(In formula, L represents the distance (unit: mm) to the said tenter in the said peeling process, W represents the width (unit: mm) of the peeled film.)

[23] A cellulose acylate film, produced by the method for producing a cellulose acylate film according to any one of [15] to [22].

[24] A polarizing plate comprising a polarizer and the cellulose acylate film according to any one of [1] to [14] and [23].

[25] A liquid crystal display device comprising the cellulose acylate film according to any one of [1] to [14] and [23] or the polarizing plate according to [24].

The cellulose acylate film which wavelength dispersion is reverse dispersion, the Rth per film thickness is large, and the display when affixed to a panel after polarizing plate processing becomes uniform in surface can be provided, and its manufacturing method can be provided. Moreover, even when it enlarges, the front contrast is favorable for the liquid crystal display device using the cellulose acylate film of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic diagram which shows an aspect at the time of manufacturing the cellulose acylate film of this invention using a dancer mechanism.
2 is a schematic view showing details of a dancer mechanism that can be used in the method for producing a cellulose acylate film of the present invention.

Hereinafter, the contents of the present invention will be described in detail. The description of constituent elements described below may be made based on a representative embodiment of the present invention, but the present invention is not limited to such embodiment. In addition, it is used by the meaning which includes with "-" the numerical value described before and after that as a lower limit and an upper limit in this specification. In this specification, what is a film conveyance direction may be called a longitudinal direction, a film longitudinal direction, or MD direction, and what is a direction orthogonal to a film conveyance direction may be called a lateral direction, a film width direction, or a TD direction.

[Cellulose Acylate Film]

The cellulose acylate film of the present invention (hereinafter also referred to as the film of the present invention) contains cellulose acylate having a total acyl substitution degree of 2.1 to 2.8, the elastic modulus in the film conveyance direction is 3200 MPa or more, and the elastic modulus in the film width direction It is characterized by the deviation of 0.5 Pa or less, and satisfy | filling following formula (1)-(3).

Equation (1) 0 ≤ ΔRe ≤ 15.0

(DELTA Re represents the value (unit: nm) which subtracted the value of in-plane retardation in wavelength 450nm from the value of retardation of the in-plane direction in wavelength 630nm.)

(2) 2 × 10 ^-3 ≤ Rth / d ≤ 6 × 10 ^-3

(In formula, Rth represents the value (unit: nm) of retardation of the film thickness direction in wavelength 550nm, d shows the film thickness (unit: nm).)

Equation (3) 1.0 ≤ E '(TD) / E' (MD) ≤ 1.43

(In formula, E '(MD) shows the elasticity modulus (unit: Mpa) of a film conveyance direction, E' (TD) shows the elastic modulus (unit: MPa) of a film width direction.)

Moreover, the film of this invention can be manufactured by the manufacturing method of the film of this invention. Hereinafter, the film of this invention is demonstrated.

<Film characteristics>

(Retardation)

In this specification, Re ((lambda)) and Rth ((lambda)) represent the in-plane retardation in the wavelength (lambda), and the retardation of the thickness direction, respectively. In the present specification, when there is no particular substrate, the wavelength? Is 550 nm. Re ((lambda)) is measured by injecting light of wavelength (lambda) nm in a film normal line direction in KOBRA 21ADH or WR (Oji Measurement Instruments Co., Ltd. product). At the time of selecting the measurement wavelength λ nm, the wavelength selection filter can be replaced by a manual, or the measured value can be converted by a program or the like and measured.

When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (?) Is calculated by the following method.

Rth (λ) refers to Re (λ) as the in-plane slow axis (as determined by KOBRA 21ADH or WR) as the inclination axis (rotation axis) (when there is no ground axis, any direction in the film plane is the rotation axis). ) A total of 6 points were measured by injecting light having a wavelength of λ nm from the inclined direction in 10-degree steps from the normal direction to the 50-degree side with respect to the film normal direction, and measuring all 6 points of the measured retardation value and the average refractive index; Based on the input film thickness value, KOBRA 21ADH or WR is calculated.

In the above description, in the case of a film having a direction in which the value of the retardation is zero at any inclination angle with the in-plane slow axis as the rotation axis from the normal direction, the retardation value at the inclination angle that is larger than the inclination angle is the symbol. After changing to negative, calculate KOBRA 21ADH or WR.

In addition, the slow axis is set as the inclination axis (rotation axis) (when there is no ground axis, any direction in the film plane is used as the rotation axis), and the retardation value is measured from any inclined two directions, and the value and the average refractive index Rth can also be calculated from the following equations (11) and (12) based on the assumption value and the input film thickness value.

Re ((theta)) represents the retardation value in the direction which inclined angle (theta) from a normal line direction. Nx in Formula (11) represents the refractive index of the slow-axis direction in surface inside, ny represents the refractive index of the direction orthogonal to nx in surface, and nz represents the refractive index of the direction orthogonal to nx and ny. d is the film thickness.

Equation (12)

Rth = {(nx + ny) / 2-nz} × d

In the case where the film to be measured cannot be expressed by a refractive index ellipsoid of one axis or two axes, or a film without an so-called optical axis, Rth (λ) is calculated by the following method.

Rth (λ) is a 10 degree step from -50 to +50 degrees with respect to the film normal direction using Re (λ) as the in-plane slow axis (judged by KOBRA 21ADH or WR) as the inclined axis (rotation axis). 11 points | pieces of light of wavelength (lambda) nm is made to inject from the inclined direction, respectively, and KOBRA21ADH or WR is computed based on the measured retardation value, the assumption value of an average refractive index, and the input film thickness value.

In the said measurement, the hypothetical value of average refractive index can use the value of the catalog of a polymer handbook (JOHN WILEY & SONS, INC) and various optical films. If the value of the average refractive index is not already known, it can be measured with an Abbe refractometer. The value of the average refractive index of a main optical film is illustrated below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), polystyrene (1.59). By inputting the assumption values and film thicknesses of these average refractive indices, KOBRA 21ADH or WR calculates nx, ny, and nz. From the calculated nx, ny, and nz, Nz = (nx-nz) / (nx-ny) is also calculated.

It is preferable that Re is 35 nm <Re <70 nm, and it is more preferable that Re is 40 nm <Re <60 nm.

In addition, Rth preferably satisfies 60 nm ≤ Rth ≤ 300 nm, more preferably 80 nm ≤ Rth ≤ 150 nm. By setting it as such Rth, VA retardation film with less color shift can be manufactured.

(Wavelength dispersion)

The film of this invention differs in retardation Re (630) of the in-plane direction in wavelength 630nm, and retardation Re (450) of the in-plane direction in wavelength 450nm (that is, ΔRe = Re (630)- Re (450)) is a reverse dispersion film that satisfies the following formula (1), and the change in viewing angle color taste when attached to the liquid crystal display device can be improved.

Equation (1) 0 nm ≤ ΔRe ≤ 15.0 nm

(DELTA Re represents the value (unit: nm) which subtracted the value of in-plane retardation in wavelength 450nm from the value of retardation of the in-plane direction in wavelength 630nm.)

As for the film of this invention, it is more preferable that said (DELTA) Re is 0.5-10 nm, and it is especially preferable that it is 1.0-9.0 nm.

(Rth / d)

The film of this invention satisfy | fills following formula (2), makes thin film of film and sufficient Rth expression compatible, and can lower the raw material cost of a film.

(2) 2 × 10 ^-3 ≤ Rth / d ≤ 6 × 10 ^-3

(In formula, Rth represents the value (unit: nm) of retardation of the film thickness direction in wavelength 550nm, d shows the film thickness (unit: nm).)

The Rth / d is 2.0 ~ 5.0 × 10 ^- more preferably ^3-3, and should preferably, 2.5 ~ 4.5 × 10.

(Standard deviation σ600 and σ-600 of slow axis orientation in the film longitudinal direction)

It is preferable that the deviation standard deviation (sigma) of the slow-axis orientation in the film width direction edge part of the film of this invention is 0.10 or less. A film width direction edge part is a place 600 mm-1000 mm away from a film width direction center part from a film width direction center part, and means the arbitrary place which is 100 mm or more from a film width direction edge part, and changes with film width.

Film of this invention is 1340 mm or more in film width, and satisfying following formula (4) and (5) is preferable from a viewpoint of fully exhibiting the effect of this invention, when used for a wide liquid crystal display device, , It is more preferable to satisfy the following formulas (4 ') and (5').

Equation (4) σ600 ≤ 0.13 °

Equation (5) σ-600 ≤ 0.13 °

(Equation (4) and (5), sigma 600 is the standard of the slow axis orientation when detecting the slow axis orientation in the film longitudinal direction on a line 600 mm away from the center line in the film width direction in one film end direction. Represents a deviation, and sigma -600 represents the standard deviation of the slow axis orientation when the slow axis orientation in the film longitudinal direction is detected on a line 600 mm away from the centerline in the film width direction to the other film end direction)

Equation (4 ') σ600 ≤ 0.10 °

Equation (5 ') σ-600 ≤ 0.10 °

Here, it is preferable that said (sigma) 600 and (sigma) -600 satisfy | fill Formula (4) and (5) when measured over 2000 m in a film longitudinal direction, and when it measures over 4000 m in a film longitudinal direction, Formula (4) And (5) is more preferable.

Although the standard deviation (sigma) 600 and (sigma) -600 of the slow-axis orientation of a film longitudinal direction may be measured offline or inline, it is preferable to measure inline from a viewpoint of eliminating the balance | deviation with the film longitudinal direction at the time of cutting. .

Moreover, when the in-line measurement of the longitudinal direction is performed on the conditions which a film flutters up and down, since each slow-axis deviation is detected largely more than actual, it is preferable to measure on the conditions which the flutter of the film up and down was suppressed to 2 mm or less. . As a method of suppressing the flutter of the upper and lower sides of such a film, the method of measuring, conveying the film of this invention on the pass roll which ran in parallel, for example is mentioned, and using the pass roll parallel-paralleled within 0.5 mm It is preferable.

When the standard deviations sigma 600 and sigma -600 of the slow axis orientation in the film longitudinal direction are measured inline, the conveyance speed and the detection time interval are not particularly limited and can be measured by any method. In the present invention, each standard deviation was calculated using data which continued 2000 m measurement every 0.033 m at 0.1 second intervals when conveyed at 20 m / min.

Moreover, about the other measurement conditions of the standard deviation (sigma) 600 and (sigma) -600 of the slow-axis orientation of a film longitudinal direction, it set as follows, and detected and calculated by the following method.

Device: High Speed Retardation Measuring Device Re100 OTSUKA Electronics Co., Ltd.

Measuring length: 2000 m

Measurement pitch: Continuous measurement every 0.1 second at 20 m / min transport

About 60000 points of data,

Calculated by (where x _i is each slow axis angle deviation and n is 60000). Variance σ

Calculated as

(Elastic modulus)

The film of this invention is 3200 Mpa or more in elasticity modulus E '(MD) of a film conveyance direction, the deviation of elastic modulus E' (TD) of a film width direction is 0.5 kPa or less, and satisfy | fills following formula (3).

Equation (3) 1.0 ≤ E '(TD) / E' (MD) ≤ 1.43

(In formula, E '(MD) shows the elasticity modulus (unit: Mpa) of a film conveyance direction, E' (TD) shows the elastic modulus (unit: MPa) of a film width direction.)

By using the film which satisfies such a physical property, the detail of the reason why the display at the time of sticking to a panel after polarizing plate processing reduces remarkably in an inside is unclear. Although not bound by any reason, in the stretching of the film containing the residual volatile matter peculiar to the actual solution film formation method, the elastic modulus of the film itself and the elastic modulus variation of the film which are thought to occur because of the low elastic modulus are consequently resulting. It was possible to improve than before. On the other hand, at the time of polarizing plate processing, when affixing the film of this invention after film forming to a polarizer as a polarizing plate protective film, it bonds, adding a tension to a film. However, the problem that the optical characteristic of the film immediately after film forming is acquired in the width | variety and the longitudinal direction by the tension of the magnitude | size which differs in the width direction and the longitudinal direction which apply to a film at the time of polarizing plate processing has not been studied much before. Therefore, when using the film of this invention which improved even the physical property, such as an elasticity modulus, it is thought that the width | variety of the tension and the nonuniformity of the length direction which apply | coat to a film at the time of polarizing plate processing can be suppressed, and the performance of a polarizing plate can be made uniform. .

It is preferable that the elasticity modulus E '(MD) of the said film conveyance direction is 3200-4500 Mpa, It is more preferable that it is 3300-4100 Mpa, It is especially preferable that it is 3500-4000 Mpa.

On the other hand, it is preferable that the elasticity modulus E '(TD) of the said film conveyance direction is 3200-5000 Mpa, It is more preferable that it is 3300-4800 Mpa, It is especially preferable that it is 4000-4700 Mpa.

Moreover, it is preferable that E '(TD) / E' (MD) is 1.05-1.40, It is more preferable that it is 1.10-1.35, It is especially preferable that it is 1.15-1.30.

The variation in the elastic modulus E '(TD) in the film width direction is 0.5 kPa or less, preferably 0.4 kPa or less, and particularly preferably 0.3 kPa or less.

(Film thickness)

Although the thickness of the film of this invention can be suitably determined according to the kind etc. of the polarizing plate to be used, Preferably it is 30-60 micrometers, More preferably, it is 35-55 micrometers. By making thickness of a film 60 micrometers or less, cost can be reduced and it is preferable.

(Layer Structure of Cellulose Acylate Film)

The film of this invention may be a single | mono layer film, and may have a laminated structure of two or more layers. In particular, when substitution degree of a cellulose acylate is 2.6-2.8, it is preferable that it is a single layer, and in the case of substitution degree 2.1-2.6, two or more layers are preferable. In that case, it is preferable that the film of this invention has a laminated structure of two or more layers, and the average total acyl substitution degree of the cellulose acylate contained in each layer differs from each other.

(Film width)

It is preferable that the film width of this invention is 1000 mm or more, It is more preferable that it is 1500 mm or more, It is especially preferable that it is 1800 mm or more.

<Cellulose acylate>

(Raw material)

A cellulose acylate used for this invention is not specifically determined except containing the cellulose acylate of at least 1 sort (s) of total acyl substitution degree 2.1-2.8. The cellulose acylate is preferably a cellulose acylate, and examples of the cellulose of the acylate raw material include cotton linter and wood pulp (softwood pulp, softwood pulp). You may mix and use according to this. For detailed descriptions of these raw celluloses, see, for example, Maruzawa, Uda, "Plastic Material Course (17) Fibrin-Based Resin," Daily Industrial Newspaper Company (Issued in 1970) or the Invention Association Publication No. 2001-1745. The cellulose described in (pages 7 to 8) can be used.

First, it describes in detail about the cellulose acylate used preferably for this invention. The glucose unit which (beta) -1,4 couple | bonded which comprises cellulose has the hydroxyl group of glass in 2, 3, and 6 positions. A cellulose acylate is a polymer (polymer) which esterified some or all of these hydroxyl groups by the acyl group of 2 or more carbon atoms. Acyl substitution degree means the ratio (100% esterification is substitution degree 1) in which the hydroxyl group of the cellulose located in 2nd, 3rd, and 6th positions is esterified.

As for the film of this invention, the total acyl substitution degree of the said cellulose acylate, ie, DS2 + DS3 + DS6, is 2.1-2.8, It is preferable that it is 2.2-2.7, More preferably, it is 2.3-2.7, Especially preferably, 2.4 to 2.6. Moreover, as for DS6 / (DS2 + DS3 + DS6), 0.08-0.66 are preferable, More preferably, it is 0.15-0.60, More preferably, it is 0.20-0.45. Here, DS2 is the substitution degree by the acyl group of the hydroxyl group of 2-position of a glucose unit (henceforth "acyl substitution degree of 2-position"), DS3 is the substitution degree by the acyl group of the hydroxyl group of 3-position (hereinafter, "3 DS6 is a substitution degree by the acyl group of the hydroxyl group of 6-position (henceforth "acyl substitution degree of 6-position"). Moreover, DS6 / (DS2 + DS3 + DS6) is a ratio of the 6-position acyl substitution degree with respect to the total acyl substitution degree, and is also called "the 6-position acyl substitution rate."

The acyl group of the cellulose acylate used for the film of this invention may be only one type, or two or more types of acyl groups may be used. When using two or more types of acyl groups, it is preferable that one is an acetyl group, and a propionyl group or a butyryl group is preferable as an acyl group of C2-C4. When the sum of the substitution degree by the acetyl group of the hydroxyl group of 2nd, 3rd and 6th position is DSA, and the sum of the substitution degree by the propionyl group or butyryl group of the hydroxyl group of 2nd, 3rd and 6th position is DSB, It is preferable that the value of DSA + DSB is 1.5-2.7. It is preferable that the value of DSB is 0-1.70, It is more preferable that it is 0-1.2, It is especially preferable that it is 0-0.5, In this invention, it is 0, ie, it is especially preferable that the said cellulose acylate is cellulose acetate. Do. By setting the values of DSA and DSB in the above ranges, a film having a small change in Re value and Rth value due to environmental humidity can be obtained, which is preferable.

Moreover, 28% or more of DSB is a substituent of 6-position hydroxyl group, More preferably, 30% or more is a substituent of 6-position hydroxyl group, It is further more preferable that 31% or more is a substituent of 6-position hydroxyl group, Especially it is 32% or more It is also preferable that it is a substituent of this 6-position hydroxyl group. By these films, a solution having a favorable solubility can be produced, and in particular, in a non-chlorinated organic solvent, a good solution can be produced. Further, a solution having a low viscosity and good filterability can be produced.

As a C2 or more acyl group of the cellulose acylate in this invention, an aliphatic group may be sufficient, an allyl group may be sufficient, and it is not specifically limited. They are alkylcarbonyl ester, alkenylcarbonyl ester, aromatic carbonyl ester, aromatic alkylcarbonyl ester, etc. of cellulose, for example, and may have group substituted further, respectively. Preferred examples thereof include propionyl group, butanoyl group, heptanoyl group, hexanoyl group, octanoyl group, decanoyl group, dodecanoyl group, tridecanoyl group, tetradecanoyl group, hexadecanoyl group, octadecanoyl group, Isobutanoyl group, tert-butanoyl group, cyclohexanecarbonyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group, etc. are mentioned. Among these, propionyl group, butanoyl group, dodecanoyl group, octadecanoyl group, tert-butanoyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group and the like are more preferable, and particularly preferably propionyl Group, butanoyl group.

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

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

The most common method for industrial synthesis of mixed fatty acid esters of cellulose is a method of acylating cellulose with mixed organic acid components containing fatty acids (acetic acid, propionic acid, valeric acid, etc.) corresponding to acetyl groups and other acyl groups or their acid anhydrides. .

The cellulose acylate used for this invention can be synthesize | combined by the method of Unexamined-Japanese-Patent No. 10-45804, for example.

<Additives>

The film of this invention may contain various additives.

In the present invention, as the additive, known high molecular weight additives and low molecular weight additives can be widely employed as additives of cellulose acylate films.

In the film of this invention, it is preferable that the addition amount of an additive is 1-35 mass% with respect to cellulose acylate, It is more preferable that it is 4-30 mass%, It is further more preferable that it is 10-25 mass%. It is easy to respond to a temperature-humidity change that the addition amount of an additive is 1 mass% or more, and a film does not whiten well if an addition amount is 35 mass% or less. In addition, the physical properties are also excellent.

Here, the additive in this invention means the component added for the purpose of the improvement of various functions, etc. of the cellulose acylate film of this invention. That is, impurities, residual solvents, etc. are not the additive in this invention.

Moreover, in this invention, two or more types of additives can be used. By using two or more types, there is an advantage that the optical properties, the film elastic modulus, the film brittleness and the web handling aptitude can be made compatible with each additive.

As said additive, For example, polycondensation ester; Retardation regulators (retardation expression agent and retardation reducing agent); Plasticizers such as phthalic acid ester and phosphoric acid ester compounds; Deterioration (oxidation) inhibitors; UV absorber; Mat agent; Organic acid (may be a peeling accelerator); Additives, such as a sugar ester compound, can be added.

Hereinafter, the additive which can be used for the film of this invention is demonstrated in detail.

(Polycondensation ester)

The polycondensation ester according to the present invention is a mixture of dicarboxylic acid (also called aromatic dicarboxylic acid) having at least one aromatic ring and at least one aliphatic dicarboxylic acid, for example, a carbon number average It is preferable that it is obtained from the dicarboxylic acid which is 5.5 or more and 10.0 or less, and the aliphatic diol whose at least 1 sort (s) of average carbon number is 2.5 or more and 7.0 or less.

The calculation of the average carbon number of an aliphatic dicarboxylic acid residue is performed separately from a dicarboxylic acid residue and a diol residue.

The value calculated by multiplying the composition carbon number by the composition carbon number (mole fraction) of the dicarboxylic acid residue is taken as the average carbon number. For example, when an adipic acid residue and a phthalic acid residue consist of 50 mol% each, it becomes 7.0 carbon atoms on average.

Moreover, also in the case of a diol residue, the average carbon number of an aliphatic diol residue is made into the value computed by multiplying the composition ratio (mole fraction) of an aliphatic diol residue by the constituent carbon number. For example, when it consists of 50 mol% of ethylene glycol residues and 50 mol% of 1, 2- propanediol residues, it becomes an average carbon number of 2.5.

It is preferable that the number average molecular weights of a polycondensation ester are 500-2000, 600-1500 are more preferable, 700-1200 are further more preferable. If the number average molecular weight of a polycondensation ester is 600 or more, volatility will become low and it will become difficult to produce the film failure and process contamination by volatilization under the high temperature conditions at the time of extending | stretching a cellulose-ester film. Moreover, compatibility with a cellulose ester becomes it high that it is 2000 or less, and the bleeding-out at the time of film forming and the heating extending | stretching hardly arises.

The number average molecular weight of the polycondensation ester of this invention can be measured and evaluated by gel permeation chromatography. Moreover, when the terminal is a polyester polyol without sealing, it can also calculate by the quantity of hydroxyl groups per weight (henceforth a hydroxyl value). The hydroxyl value measures the amount (mg) of potassium hydroxide required for neutralization of excess acetic acid after acetylating the polyester polyol.

It is preferable that the dicarboxylic acid as a mixture of the aromatic dicarboxylic acid and aliphatic dicarboxylic acid which concerns on this invention is dicarboxylic acid whose average of carbon number is 5.5 or more and 10.0 or less. More preferably, they are 5.6 or more and 8 or less.

If the average number of carbon atoms is 5.5 or more, a polarizing plate excellent in durability can be obtained. If the average of carbon number is 10 or less, it is excellent in compatibility with respect to a cellulose ester, and generation | occurrence | production of a bleed out can be suppressed in the film forming process of a cellulose ester film.

The polycondensation ester which concerns on this invention can be used as a plasticizer.

Aromatic dicarboxylic acid residue is contained in the polycondensation ester obtained from the dicarboxylic acid containing diol and aromatic dicarboxylic acid.

In this specification, a residue is a partial structure of a polycondensation ester, and shows the partial structure which has the characteristic of the monomer which forms a polycondensation ester. For example, the dicarboxylic acid residue formed from dicarboxylic acid HOOC-R-COOH is -OC-R-CO-.

It is preferable that it is 40 mol% or more, and, as for the aromatic dicarboxylic acid residue ratio of the polycondensation ester used for this invention, it is preferable that they are 40 mol%-95 mol%. It is more preferable that they are 45 mol%-70 mol%, and it is still more preferable that they are 50 mol%-70 mol%.

By making aromatic dicarboxylic acid residue ratio into 40 mol% or more, the cellulose-ester film which shows sufficient optical anisotropy is obtained, and the polarizing plate excellent in durability can be obtained. Moreover, when it is 95 mol% or less, it is excellent in compatibility with a cellulose ester, and it can prevent that a bleed out does not generate | occur | produce well also at the time of film forming and heat extending | stretching of a cellulose ester film.

The aromatic dicarboxylic acid used in the present invention is, for example, an aromatic dicarboxylic acid such as phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, Acid, 2,8-naphthalene dicarboxylic acid, or 2,6-naphthalene dicarboxylic acid. Phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid are preferable, phthalic acid and terephthalic acid are more preferable, and terephthalic acid is more preferable.

An aromatic dicarboxylic acid residue is formed by the aromatic dicarboxylic acid used for mixing in the polycondensation ester.

Specifically, the aromatic dicarboxylic acid residue preferably contains at least one of phthalic acid residue, terephthalic acid residue and isophthalic acid residue, more preferably at least one of phthalic acid residue and terephthalic acid residue, Preferably a terephthalic acid residue.

That is, by using terephthalic acid as the aromatic dicarboxylic acid for mixing in the formation of the polycondensation ester, the compatibility with the cellulose ester is more excellent, and the bleed-out is well performed at the time of film forming and heat stretching of the cellulose ester film. It can be set as the cellulose-ester film which does not generate | occur | produce. Moreover, 1 type may be sufficient as aromatic dicarboxylic acid, and 2 or more types may be used for it. When using 2 types, it is preferable to use phthalic acid and terephthalic acid.

By using together two aromatic dicarboxylic acids of phthalic acid and terephthalic acid, it is preferable at the point which can soften the polycondensation ester at normal temperature, and becomes easy to handle.

It is preferable that content of the terephthalic acid residue in the dicarboxylic acid residue of a polycondensation ester is 40 mol%-95 mol%, It is preferable that it is 45 mol%-70 mol%, It is preferable that it is 50 mol%-70 mol%. .

By making terephthalic acid residue ratio into 40 mol% or more, the cellulose-ester film which shows sufficient optical anisotropy is obtained. Moreover, when it is 95 mol% or less, it is excellent in compatibility with a cellulose ester, and it can prevent that a bleed out does not generate | occur | produce well also at the time of film forming and heat extending | stretching of a cellulose ester film.

Aliphatic dicarboxylic acid residue is contained in the polycondensation ester obtained from the dicarboxylic acid containing diol and aliphatic dicarboxylic acid.

In this specification, a residue is a partial structure of a polycondensation ester, and shows the partial structure which has the characteristic of the monomer which forms a polycondensation ester. For example, the dicarboxylic acid residue formed from dicarboxylic acid HOOC-R-COOH is -OC-R-CO-.

Aliphatic dicarboxylic acids preferably used in the present invention include, for example, oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, pimeric acid, suberic acid, azelaic acid, Sebacic acid, dodecanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and the like.

In the polycondensation ester, an aliphatic dicarboxylic acid residue is formed from an aliphatic dicarboxylic acid used for mixing.

It is preferable that average carbon number is 5.5 or more and 10.0 or less, It is more preferable that it is 5.5-8.0, It is still more preferable that dicarboxylic acid residue is 5.5-7.0. When the average carbon number of the aliphatic diol is 7.0 or less, it is possible to reduce the heating loss of the compound and to prevent the occurrence of a planar failure caused by process contamination due to bleed out during drying of the cellulose acylate web. Moreover, when the average carbon number of aliphatic diol is 2.5 or more, it is excellent in compatibility, and precipitation of a polycondensation ester does not occur easily, and it is preferable.

It is preferable to contain a succinic acid residue specifically, and when using two types, it is preferable to contain a succinic acid residue and an adipic acid residue.

That is, one type of aliphatic dicarboxylic acid may be sufficient for mixing in formation of a polycondensation ester, 2 or more types may be used, and when using 2 types, it is preferable to use succinic acid and adipic acid. When using 1 type, it is preferable to use succinic acid. The average carbon number of a diol residue can be adjusted to a desired value, and it is preferable at the point of compatibility with a cellulose ester.

In this invention, it is preferable to use 2 types or 3 types of dicarboxylic acid. When using 2 types, it is necessary to use 1 type of aliphatic dicarboxylic acid and aromatic dicarboxylic acid, and when using 3 types, 1 type of aliphatic dicarboxylic acid and 2 types of aromatic dicarboxylic acid, or aliphatic Two kinds of dicarboxylic acid and one kind of aromatic dicarboxylic acid can be used. It is because it is easy to adjust the value of the average carbon number of a dicarboxylic acid residue, can make content of an aromatic dicarboxylic acid residue into a preferable range, and can improve durability of a polarizer.

Aliphatic diol residue is contained in the polycondensation ester obtained from the dicarboxylic acid containing aliphatic diol and dicarboxylic acid.

In this specification, a residue is a partial structure of a polycondensation ester, and shows the partial structure which has the characteristic of the monomer which forms a polycondensation ester. For example, the diol residue formed from diol HO-R-OH is -O-R-O-.

Diols forming the polycondensation esters include aromatic diols and aliphatic diols and include at least aliphatic diols.

The polycondensation ester preferably contains an aliphatic diol residue having an average carbon number of 2.5 or more and 7.0 or less. Preferably they are aliphatic diol residues whose average carbon number is 2.5 or more and 4.0 or less. When the average carbon number of the aliphatic diol residue is 3.0 or less, the compatibility with the cellulose ester is not lowered, the bleed out is less likely to occur, and the heating loss of the compound is not excessively increased, and at the time of drying the cellulose acylate web Surface defects that are thought to be caused by process contamination are less likely to occur. Moreover, when average carbon number of aliphatic diol residue is less than 2.0, synthesis becomes difficult.

Examples of the aliphatic diols used in the present invention include alkyldiols and alicyclic diols, and examples thereof include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1, 3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentylglycol), 2,2- Diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl-1 , 5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, diethylene glycol, cyclohexanedimethanol, and the like, which are used together with ethylene glycol as one kind or a mixture of two or more kinds. desirable.

The preferred aliphatic diol is at least one of ethylene glycol, 1,2-propanediol and 1,3-propanediol, and particularly preferably at least one of ethylene glycol and 1,2-propanediol. When using 2 types, it is preferable to use ethylene glycol and 1, 2- propanediol. Crystallization of the polycondensation ester can be prevented by using 1,2-propanediol or 1,3-propanediol.

The diol residue is formed in the polycondensation ester by the diol used for mixing.

The diol residue preferably contains at least one of an ethylene glycol residue, a 1,2-propanediol residue and a 1,3-propanediol residue, more preferably an ethylene glycol residue or a 1,2-propanediol residue.

In the aliphatic diol residue, the ethylene glycol residue is preferably 20 mol% to 100 mol%, more preferably 50 mol% to 100 mol%.

The terminal of the polycondensation ester of the present invention may be a diol or carboxylic acid without sealing, or may be subjected to a so-called terminal sealing by reacting monocarboxylic acids or monoalcohols.

As monocarboxylic acids used for sealing, acetic acid, propionic acid, butanoic acid, etc. are preferable, acetic acid or propionic acid is more preferable, and acetic acid is most preferable. As monoalcohols used for sealing, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, etc. are preferable, and methanol is the most preferable. If carbon number of the monocarboxylic acids used at the terminal of a polycondensation ester is three or less, the heating loss of a compound will not become large and a planar failure will not arise.

More preferably, the terminal of the polycondensation ester of the present invention is free of encapsulation and thus remains a diol residue, or more preferably encapsulated with acetic acid or propionic acid.

Both ends of the polycondensation ester according to the present invention may be sealed or unsealed.

When both ends of the condensate are unsealed, the polycondensation ester is preferably a polyester polyol.

As one of the aspects of the polycondensation ester which concerns on this invention, the polycondensation ester whose carbon number of an aliphatic diol residue is 2.5 or more and 7.0 or less and the both ends of a condensate is mentioned.

When both ends of a condensate are sealed, it is preferable to make it react by monocarboxylic acid and to seal. At this time, both ends of the polycondensation ester are monocarboxylic acid residues. In this specification, a residue is a partial structure of a polycondensation ester, and shows the partial structure which has the characteristic of the monomer which forms a polycondensation ester. For example, the monocarboxylic acid residue formed from monocarboxylic acid R-COOH is R-CO-. Preferably it is an aliphatic monocarboxylic acid residue, It is more preferable that a monocarboxylic acid residue is a C22 or less aliphatic monocarboxylic acid residue, It is still more preferable that it is a C3 or less aliphatic monocarboxylic acid residue.

Moreover, it is preferable that it is a C2 or more aliphatic monocarboxylic acid residue, and it is especially preferable that it is a C2 aliphatic monocarboxylic acid residue.

As one of the aspects of the polycondensation ester which concerns on this invention, the polycondensation ester whose carbon number of aliphatic diol residue is larger than 2.5 and is 7.0 or less, and both ends of a condensate are monocarboxylic acid residue is mentioned.

When the carbon number of the monocarboxylic acid residues at both ends of the polycondensation ester is 3 or less, volatility decreases, and the loss by heating of the polycondensation ester does not increase, and the occurrence of process contamination and the occurrence of surface failure can be reduced. have.

That is, as monocarboxylic acids used for sealing, aliphatic monocarboxylic acid is preferable. The monocarboxylic acid is more preferably an aliphatic monocarboxylic acid having 2 to 22 carbon atoms, still more preferably an aliphatic monocarboxylic acid having 2 to 3 carbon atoms, and particularly preferably an aliphatic monocarboxylic acid residue having 2 carbon atoms.

For example, acetic acid, propionic acid, butanoic acid, benzoic acid and derivatives thereof are preferable, acetic acid or propionic acid is more preferable, and acetic acid is most preferable.

The monocarboxylic acid used for sealing may mix 2 or more types.

The both ends of the polycondensation ester of the present invention are preferably sealed with acetic acid or propionic acid, and most preferably, both ends are acetyl ester residues (sometimes referred to as acetyl residues).

When sealing both ends, the state in normal temperature does not become a solid form, handling becomes favorable, and the cellulose-ester film excellent in humidity stability and polarizing plate durability can be obtained.

Although the specific example of the polycondensation ester concerning this invention is described in the following Table 1, it is not limited to these.

Synthesis of the polycondensation ester according to the present invention is a thermal melt condensation method of a polyester reaction of a diol and dicarboxylic acid or a transesterification reaction by a conventional method, or an interface between acid chlorides of these acids and glycols. It can be synthesize | combined easily by any of the condensation methods. Moreover, about the polycondensation ester which concerns on this invention, there is a detailed description in Murai Koichi horseshoe plasticizer "Theory and application of a plasticizer" (the Saisho Shobo Co., Ltd., the first edition of March 1, 1973). Japanese Unexamined Patent Application Publication Nos. Hei 05-155809, Japanese Unexamined Patent Publication No. 05-155810, Japanese Unexamined Patent Application Publication No. 5-197073, Japanese Unexamined Patent Application Publication No. 2006-259494 and Japanese Unexamined Patent Application Publication No. 07-330670 The material described in each of Unexamined-Japanese-Patent No. 2006-342227, Unexamined-Japanese-Patent No. 2007-003679, etc. can also be used.

It is preferable that content of the said polycondensation ester in a cellulose ester film is 5-40 mass% with respect to the amount of cellulose esters, It is more preferable that it is 8-30 mass%, It is most preferable that it is 10-25 mass%. .

Less than 1 mass% is preferable, and, as for content in the cellulose-ester film of aliphatic diol, dicarboxylic acid ester, or diol ester which is a raw material which the polycondensate of this invention contains, more preferably less than 0.5 mass%. Examples of the dicarboxylic acid esters include dimethyl phthalate, di (hydroxyethyl) phthalate, dimethyl terephthalate, di (hydroxyethyl) terephthalate, di (hydroxyethyl) adipate and di (hydroxyethyl) have. Ethylene diacetate, propylene diacetate, etc. are mentioned as diol ester.

The type and ratio of each residue of the dicarboxylic acid residue, diol residue, and monocarboxylic acid residue contained in the polycondensation ester used in the present invention can be measured by a conventional method using H-NMR. Usually, chloroform can be used as a solvent.

The number average molecular weight of the polycondensation ester can be measured by a conventional method using GPC (Gel Permeation Chromatography), and polystyrene can be used as standard data.

The measurement of the hydroxyl value of the polycondensation ester can be carried out by the acetic anhydride method described in Japanese Industrial Standard JIS K 3342 (abolished). In the case where the polycondensate is a polyester polyol, the hydroxyl value is preferably 50 or more and 190 or less, and more preferably 50 or more and 130 or less.

(Retardation expression agent)

It is preferable that the film of this invention does not contain 3 mass% or more of Re expression agents with respect to the said cellulose acylate. In addition, in order to express a retardation value, you may contain a retardation expression agent, It is preferable that content of Re expression agent is less than 3 mass% with respect to the said cellulose acylate. Although there is no restriction | limiting in particular as said retardation expression agent, What consists of rod-shaped or disk shaped compounds is mentioned. As the rod-shaped or disk-shaped compound, a compound having at least two aromatic rings can be preferably used as the retardation expression agent.

It is preferable that it is 0.1 mass part or more and less than 3 mass parts with respect to 100 mass parts of cellulose acylate components, and, as for the addition amount of the retardation expression agent which consists of rod-shaped compounds, it is more preferable that it is 0.5 mass part or more and less than 2 mass parts. It is preferable that the disk shaped compound contained in the said retardation expression agent is 0.1 mass part or more and less than 3 mass parts with respect to 100 mass parts of said cellulose acylates, It is more preferable that it is 0.5 mass part or more and less than 2 mass parts, 0.5 mass parts It is especially preferable that it is less than 1 mass part or more.

Since the disk-shaped compound is superior to the rod-shaped compound in the Rth retardation expression property, it is preferably used especially when a large Rth retardation is required. You may use together two or more types of retardation expression agents.

It is preferable that a retardation expression agent has maximum absorption in the wavelength range of 250-400 nm, and it is preferable that it does not have absorption in a visible region substantially.

A disk shaped compound is demonstrated. As the disk shaped compound, a compound having at least two aromatic rings can be used.

In the present specification, the "aromatic ring" includes an aromatic hetero ring in addition to the aromatic hydrocarbon ring.

The aromatic hydrocarbon ring is particularly preferably a 6 membered ring (ie, a benzene ring).

Aromatic hetero rings are generally unsaturated hetero rings. It is preferable that it is a 5-membered ring, a 6-membered ring, or a 7-membered ring, and, as for an aromatic hetero ring, it is more preferable that it is a 5-membered ring or a 6-membered ring. Aromatic heterocycles generally have the largest number of double bonds. As a hetero atom, a nitrogen atom, an oxygen atom, and a sulfur atom are preferable, and a nitrogen atom is especially preferable. Examples of aromatic hetero rings include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole Ring, pyran ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring.

As an aromatic ring, a benzene ring, a condensed benzene ring, and biphenyls are preferable. Especially 1,3,5-triazine ring is used preferably. Specifically, for example, the compound disclosed in JP 2001-166144 A is preferably used.

It is preferable that carbon number of the aromatic ring which a retardation expression agent has is 2-20, It is more preferable that it is 2-12, It is still more preferable that it is 2-8, It is most preferable that it is 2-6.

The bonding relationship between two aromatic rings can be classified into (a) forming a condensed ring, (b) directly connecting to a single bond, and (c) bonding through a linking group (because it is an aromatic ring, Spiro bonds cannot be formed). The coupling relationship may be any of (a)-(c).

Examples of the condensed ring (condensed ring of two or more aromatic rings) of (a) include indene ring, naphthalene ring, azulene ring, fluorene ring, phenanthrene ring, anthracene ring, acenaphthylene ring, biphenylene ring, Naphthacene ring, pyrene ring, indole ring, isoindole ring, benzofuran ring, benzothiophene ring, indoliazine ring, benzoxazole ring, benzothiazole ring, benzoimidazole ring, benzotriazole ring, purine ring, Indazole ring, chromen ring, quinoline ring, isoquinoline ring, quinolysin ring, quinazoline ring, cinnaline ring, quinoxaline ring, phthalazine ring, pteridine ring, carbazole ring, acridine ring , Phenanthridine rings, xanthene rings, phenazine rings, phenothiazine rings, phenoxatiin rings, phenoxazine rings and thianthrene rings. Preferred are naphthalene ring, azulene ring, indole ring, benzoxazole ring, benzothiazole ring, benzoimidazole ring, benzotriazole ring and quinoline ring.

It is preferable that the single bond of (b) is a bond between carbon atoms of two aromatic rings. Two aromatic rings may be bonded by two or more single bonds, and an aliphatic ring or a non-aromatic heterocyclic ring may be formed between two aromatic rings.

It is preferable that the linking group of (c) couple | bonds with the carbon atom of two aromatic rings. It is preferable that a coupling group is an alkylene group, an alkenylene group, an alkynylene group, -CO-, -O-, -NH-, -S-, or a combination thereof. An example of a connector made of a combination is shown below. In addition, the relationship between the left and right of the following example of a connector may be reversed.

c1: -CO-O-

c2: -CO-NH-

c3: -alkylene-O-

c4 is: -NH-CO-NH-

c5: -NH-CO-O-

c6: -O-CO-O-

c7: -O-alkylene-O-

c8: -CO-alkenylene-

c9: -CO-alkenylene-NH-

c10: -CO-alkenylene-O-

C11: -alkylene-CO-O-alkylene-O-CO-alkylene-

C12: -O-alkylene-CO-O-alkylene-O-CO-alkylene-

c13: -O-CO-alkylene-CO-O-

c14: -NH-CO-alkenylene-

c15: -O-CO-alkenylene-

The aromatic ring and the linking group may have a substituent.

Examples of the substituent include halogen atom (F, Cl, Br, I), hydroxyl group, carboxyl group, cyano group, amino group, nitro group, sulfo group, carbamoyl group, sulfamoyl group, ureide group, alkyl group, alkenyl group , Alkynyl group, aliphatic acyl group, aliphatic acyloxy group, alkoxy group, alkoxycarbonyl group, alkoxycarbonylamino group, alkylthio group, alkylsulfonyl group, aliphatic amide group, aliphatic sulfonamide group, aliphatic substituted amino group, aliphatic substituted carbamoyl group , Aliphatic substituted sulfamoyl groups, aliphatic substituted uraid groups and non-aromatic heterocyclic groups.

It is preferable that carbon number of an alkyl group is 1-8. A chain alkyl group is more preferable than a cyclic alkyl group, and a linear alkyl group is especially preferable. The alkyl group may further have a substituent (for example, a hydroxyl group, a carboxy group, an alkoxy group, an alkyl substituted amino group). Examples of the alkyl group (including a substituted alkyl group) include a methyl group, ethyl group, n-butyl group, n-hexyl group, 2-hydroxyethyl group, 4-carboxybutyl group, 2-methoxyethyl group and 2-diethylaminoethyl group Each group of is included.

It is preferable that carbon number of an alkenyl group is 2-8. A chain alkenyl group is more preferable than a cyclic alkenyl group, and a linear alkenyl group is especially preferable. The alkenyl group may further have a substituent. Examples of the alkenyl group include a vinyl group, allyl group, and 1-hexenyl group.

It is preferable that carbon number of an alkynyl group is 2-8. A chain alkynyl group is more preferable than a cyclic alkynyl group, and a linear alkynyl group is especially preferable. The alkynyl group may further have a substituent. Examples of the alkynyl group include an ethynyl group, 1-butynyl group and 1-hexynyl group.

It is preferable that carbon number of an aliphatic acyl group is 1-10. Examples of aliphatic acyl groups include acetyl groups, propanoyl groups and butanoyl groups.

It is preferable that carbon number of an aliphatic acyloxy group is 1-10. Examples of aliphatic acyloxy groups include acetoxy groups.

It is preferable that carbon number of an alkoxy group is 1-8. The alkoxy group may further have a substituent (for example, an alkoxy group). Examples of the alkoxy group (including a substituted alkoxy group) include methoxy group, ethoxy group, butoxy group and methoxyethoxy group.

It is preferable that carbon number of an alkoxycarbonyl group is 2-10. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group.

It is preferable that carbon number of the alkoxycarbonylamino group is 2-10. Examples of the alkoxycarbonylamino group include a methoxycarbonylamino group and an ethoxycarbonylamino group.

It is preferable that carbon number of an alkylthio group is 1-12. Examples of the alkylthio group include methylthio group, ethylthio group and octylthio group.

It is preferable that carbon number of an alkylsulfonyl group is 1-8. Examples of the alkylsulfonyl group include a methanesulfonyl group and an ethanesulfonyl group.

It is preferable that carbon number of an aliphatic amide group is 1-10. Examples of aliphatic amide groups include acetamide.

It is preferable that carbon number of an aliphatic sulfonamide group is 1-8. Examples of aliphatic sulfonamide groups include methanesulfonamide groups, butanesulfonamide groups and n-octanesulfonamide groups.

It is preferable that carbon number of an aliphatic substituted amino group is 1-10. Examples of the aliphatic substituted amino group include a dimethylamino group, diethylamino group and 2-carboxyethylamino group.

It is preferable that carbon number of an aliphatic substituted carbamoyl group is 2-10. Examples of aliphatic substituted carbamoyl groups include methylcarbamoyl groups and diethylcarbamoyl groups.

It is preferable that carbon number of an aliphatic substituted sulfamoyl group is 1-8. Examples of the aliphatic substituted sulfamoyl group include a methyl sulfamoyl group and a diethyl sulfamoyl group.

It is preferable that carbon number of an aliphatic substituted ureide group is 2-10. Examples of the aliphatic substituted ureide group include a methyl ureide group.

Examples of the nonaromatic heterocyclic group include a piperidino group and a morpholino group.

It is preferable that the molecular weight of a retardation expression agent is 300-800.

It is preferable to use the triazine compound represented by following General formula (I) as a disk shaped compound.

[Formula 2]

In general formula (I)

In the general formula (I):

R ²⁰¹ each independently represents an aromatic ring or a heterocyclic ring having a substituent on at least any of ortho, meta and para positions.

X ²⁰¹ each independently represents a single bond or -NR ^202- . Here, R ²⁰² each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, an alkenyl group, an aryl group, or a heterocyclic group.

The aromatic ring represented by R ²⁰¹ is preferably phenyl or naphthyl, and particularly preferably phenyl. The aromatic ring represented by R ²⁰¹ may have at least one substituent at any substitution position. Examples of the substituent include halogen atoms, hydroxyl groups, cyano groups, nitro groups, carboxyl groups, alkyl groups, alkenyl groups, aryl groups, alkoxy groups, alkenyloxy groups, aryloxy groups, acyloxy groups, alkoxycarbonyl groups and alkenyloxy Carbonyl group, aryloxycarbonyl group, sulfamoyl group, alkyl substituted sulfamoyl group, alkenyl substituted sulfamoyl group, aryl substituted sulfamoyl group, sulfonamide group, carbamoyl, alkyl substituted carbamoyl group, alkenyl substituted carbamoyl group, Aryl substituted carbamoyl groups, amide groups, alkylthio groups, alkenylthio groups, arylthio groups and acyl groups are included.

It is preferable that the heterocyclic group represented by R ²⁰¹ has aromaticity. The heterocyclic ring having aromaticity is generally an unsaturated heterocyclic ring, preferably a heterocyclic ring having the largest double bond. The heterocyclic ring is preferably a 5-membered ring, a 6-membered ring or a 7-membered ring, more preferably a 5-membered ring or a 6-membered ring, and most preferably a 6-membered ring. It is preferable that the hetero atom of a hetero ring is a nitrogen atom, a sulfur atom, or an oxygen atom, and it is especially preferable that it is a nitrogen atom. As the aromatic ring-containing heterocyclic ring, a pyridine ring (2-pyridyl or 4-pyridyl) is particularly preferable as the heterocyclic ring group. The heterocyclic group may have a substituent. Examples of the substituent of the heterocyclic group are the same as those of the substituent of the aryl moiety.

It is preferable that the heterocyclic group in the case where X ²⁰¹ is a single bond is a heterocyclic group having a free valence in the nitrogen atom. It is preferable that the heterocyclic group which has a free valency in a nitrogen atom is a 5-membered ring, a 6-membered ring, or a 7-membered ring, It is more preferable that it is a 5-membered ring or a 6-membered ring, It is most preferable that it is a 5-membered ring. The heterocyclic group may have a plurality of nitrogen atoms. Moreover, the heterocyclic group may have hetero atoms (for example, O and S) other than a nitrogen atom. The example of the heterocyclic group which has a free valency in a nitrogen atom is shown below. Here, -C ₄ H ₉ ⁿ represents nC ₄ H ₉ .

(3)

Although the alkyl group which R <^202> represents may be a cyclic alkyl group or a chain alkyl group, a chain alkyl group is preferable and a linear alkyl group is more preferable than a branched chain alkyl group. The number of carbon atoms in the alkyl group is preferably 1 to 30, more preferably 1 to 20, still more preferably 1 to 10, still more preferably 1 to 8, and most preferably 1 to 6 . The alkyl group may have a substituent. Examples of the substituent include a halogen atom, an alkoxy group (eg, methoxy group, ethoxy group) and an acyloxy group (eg, acryloyloxy group, methacryloyloxy group).

The alkenyl group represented by R ²⁰² may be a cyclic alkenyl group or a chain alkenyl group, preferably a chain alkenyl group, and more preferably a linear alkenyl group than a branched chain alkenyl group. . The number of carbon atoms in the alkenyl group is preferably 2 to 30, more preferably 2 to 20, still more preferably 2 to 10, still more preferably 2 to 8, and most preferably 2 to 6 desirable. The alkenyl group may have a substituent. Examples of the substituent are the same as the substituent of the alkyl group described above.

The aromatic ring group and heterocyclic group which R <^202> represents is the same as the aromatic ring and heterocyclic ring which R <^201> represents, and its preferable range is also the same. An aromatic ring group and a heterocyclic group may further have a substituent, and the example of a substituent is the same as the substituent of the aromatic ring and heterocyclic ring of R <^201> .

The compound represented by general formula (I) can be synthesize | combined by a well-known method, such as the method of Unexamined-Japanese-Patent No. 2003-344655, for example. Details of the retardation expression agent are described on page 49 of Publication Gazette 2001-1745.

As a retardation expression agent of this invention, a polymeric additive can also be used similarly to the said low molecular weight compound. Here, in the present invention, the polymer used as the polycondensation ester may also function as a retardation expression agent. As a polymeric retardation expression agent which is also said polycondensation ester, the copolymer of the said aromatic polyester type polymer, the said aromatic polyester type polymer, and other resin is preferable.

It is more preferable that the retardation expression agent of the present invention is a Re expression agent from the viewpoint of efficiently expressing Re and realizing an appropriate Nz factor. As Re expression agent, the disk shaped compound, rod-shaped compound, etc. are mentioned among the said retardation expression agents.

(Retardation reducer)

In this invention, the compound of ester type which is a phosphoric acid type, and a compound known as an additive of a cellulose acylate film can be employ | adopted widely as a retardation reducing agent.

As a polymeric retardation reducing agent, it selects from the polyester type polymer which is phosphoric acid type, a styrene type polymer and an acryl type polymer, these copolymers, and an acrylic type polymer and a styrene type polymer are preferable. Moreover, it is preferable that at least 1 sort (s) of polymer which has negative intrinsic birefringence, such as a styrene polymer and an acryl-type polymer, is contained.

As a low molecular weight retardation reducing agent, the following is mentioned. These may be solid or an oily substance may be sufficient as them. That is, it is not specifically limited in the melting point or boiling point. For example, it is mixing of 20 degrees C or less and 20 degrees C or more ultraviolet absorbing material, similarly mixing deterioration inhibitor, etc. Moreover, as an infrared absorbing dye, it is described, for example in Unexamined-Japanese-Patent No. 2001-194522. Moreover, although the addition time may be added at any time in a cellulose acylate solution (dope) manufacturing process, you may add and perform the process of adding and preparing an additive to the last preparation process of a dope preparation process. In addition, the addition amount of each raw material is not specifically limited as long as a function is expressed.

Although it does not specifically limit as a low molecular weight retardation reducing agent, The detail is described in Unexamined-Japanese-Patent No. 2007-272177.

The compound described as general formula (1) in Unexamined-Japanese-Patent No. 2007-272177 can be manufactured with the following method.

The compound of the publication general formula (1) can be obtained by condensation reaction of a sulfonyl chloride derivative and an amine derivative.

The compound of Unexamined-Japanese-Patent No. 2007-272177 General formula (2) is a dehydration condensation reaction of carboxylic acids and amines using a condensing agent (for example, dicyclohexylcarbodiimide (DCC), etc.) or car It can obtain by substitution reaction of an acid chloride derivative and an amine derivative, and the like.

(Plasticizer)

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

(Deterioration inhibitor)

In the present invention, known deterioration (oxidation) inhibitors in cellulose acylate solution, for example, 2,6-di-tert-butyl-4-methylphenol, 4,4'-thiobis- (6-tert-butyl -3-methylphenol), 1,1'-bis (4-hydroxyphenyl) cyclohexane, 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,5-di-tert Phenolic or hydroquinone-based antioxidants such as -butylhydroquinone and pentaerythryl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] can be added. have. Further, tris (4-methoxy-3,5-diphenyl) phosphite, tris (nonylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, bis (2,6-di It is preferable to use phosphorus antioxidants, such as -tert- butyl- 4-methylphenyl) pentaerythritol diphosphite and bis (2, 4- di-tert- butylphenyl) pentaerythritol diphosphite. The addition amount of a deterioration inhibitor adds 0.05-5.0 mass parts with respect to 100 mass parts of cellulose resins.

(Ultraviolet absorber)

In this invention, a ultraviolet absorber is preferably used for the cellulose acylate solution from a viewpoint of prevention of deterioration, such as a polarizing plate or a liquid crystal. As a ultraviolet absorber, the thing which is excellent in the absorption ability of the ultraviolet-ray of wavelength 370nm or less, and has the low absorption of the visible light of wavelength 400nm or more from a viewpoint of favorable liquid crystal display property is used preferably. As a specific example of the ultraviolet absorber used preferably for this invention, a hindered phenol type compound, a hydroxy benzophenone type compound, a benzotriazole type compound, a salicylic acid ester type compound, a benzophenone type compound, a cyanoacrylate, for example The compound, nickel complex salt compound, etc. are mentioned. Examples of the hindered phenolic compound include 2,6-di-tert-butyl-p-cresol and pentaerythryl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate], N, N'-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamid), 1,3,5-trimethyl-2,4,6-tris ( 3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris (3,5-di-tert-butyl-4-hydroxybenzyl) -isocyanurate, etc. are mentioned. Examples of the benzotriazole-based compound include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole and 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6 -(2H-benzotriazol-2-yl) phenol), (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino)- 1,3,5-triazine, triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], N, N'-hexamethylenebis (3, 5-di-tert-butyl-4-hydroxy-hydrocinnamid), 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) Benzene, 2 (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, (2 (2'-hydroxy-3', 5'-di-tert- Amylphenyl) -5-chlorobenzotriazole, 2,6-di-tert-butyl-p-cresol, pentaerythryl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxy Phenyl) propionate], etc. The addition amount of these ultraviolet inhibitors is cellulose acylate. A mass ratio in the total flow 1 ppm ~ 1.0% is preferred, and, 10 ~ 1000 ppm are more preferred.

(Made by Matt)

It is preferable that the film of this invention contains a mat agent from a viewpoint of film slipperiness | lubricacy and stable manufacture. The mat agent may be a mat agent of an inorganic compound or a mat agent of an organic compound.

Specific examples of the matting agent of the inorganic compound include inorganic compounds containing silicon (for example, silicon dioxide, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, etc.), titanium oxide, zinc oxide, and oxidation Aluminum, barium oxide, zirconium oxide, strontium oxide, antimony oxide, tin oxide, tin oxide and antimony, calcium carbonate, talc, clay, calcined kaolin and calcium phosphate are preferable, and more preferably inorganic compounds containing silicon, Although it is zirconium oxide, since the turbidity of a cellulose acylate film can be reduced, silicon dioxide is used especially preferably. As microparticles | fine-particles of the said silicon dioxide, the commercial item which has brand names, such as aerosil R972, R974, R812, 200, 300, R202, OX50, TT600 (above Nippon Aerosil Co., Ltd. product), is mentioned, for example. Can be used. As microparticles | fine-particles of the said zirconium oxide, what is marketed under brand names, such as aerosil R976 and R811 (above Nippon Aerosil Co., Ltd. product), can be used, for example.

As a preferable specific example of the mat agent of the said organic compound, polymer, such as a silicone resin, a fluororesin, and an acrylic resin, for example, is preferable, and a silicone resin is used preferably especially. Among the silicone resins, in particular, those having a three-dimensional network structure are preferable, and for example, tospul 103, tospul 105, tospul 108, tospul 120, tospul 145, tospul 3120 and tospul 240 (or more). A commercial item which has brand names, such as Toshiba Silicone Co., Ltd., can be used.

When adding these mat agents to a cellulose acylate solution, it is not specifically limited to the method, If a desired cellulose acylate solution can be obtained by any method, there will be no problem. For example, you may contain an additive in the step of mixing a cellulose acylate and a solvent, and may add an additive after preparing a mixed solution with a cellulose acylate and a solvent. Furthermore, you may add and mix immediately before dope is cast | flow_spread, it is what is called immediately before, and the mixing is used by providing a screw kneading | mixing online. Specifically, a static mixer such as an inline mixer is preferable, and as the inline mixer, for example, a static mixer SWJ (Toray Stationary Tube Mixer Hi-Mixer) (manufactured by Toray Engineering) is preferable. In addition, regarding inline addition, in order to eliminate density | variation fluctuations, agglomeration of particle | grains, etc., Unexamined-Japanese-Patent No. 2003-053752 mixes additive liquids of a different composition with main raw material dope in the manufacturing method of a cellulose acylate film. The invention which removes aggregation of concentration variation, mat particle | grains, etc. is described by making the distance L of the addition nozzle front end and the start end of an inline mixer into 5 times or less of the main raw material piping internal diameter d. As a further preferred embodiment, the distance L between the leading end opening of the additive liquid supply nozzle having a composition different from the main raw material dope and the starting end of the inline mixer is set to 10 times or less of the inner diameter d of the supply nozzle leading opening, and the inline mixer It is described that it is a static agitated tube mixer or a dynamic stirred tube mixer. More specifically, it is disclosed that the flow rate ratio of the cellulose acylate film main raw material dope / in-line addition liquid is 10/1 to 500/1, preferably 50/1 to 200/1. Moreover, it melt | dissolves as a method of adding an additive also to Unexamined-Japanese-Patent No. 2003-014933 which is an invention aimed at the retardation film which has little additive bleed-out, and there is no peeling phenomenon between layers, and it is also excellent in slipperiness | lubricacy, and is excellent in transparency. Although it may add in a kiln, the solution which melt | dissolved or disperse | distributed or disperse | distributed the additive and the additive between the melting kiln and the co-fuel die may be added to the dope in a liquid feeding, In the latter case, in order to improve mixing property, mixing with a static mixer etc. It is described that it is desirable to form the means.

(Organic acid)

It is preferable that the film of this invention contains the organic acid represented by following General formula (1).

In general formula (1)

XL- (R ¹ ) _n

(In formula, X represents an acidic group whose acid dissociation constant is 5.5 or less, L represents a single bond or a bivalent or more coupling group, R <^1> is a C6-C30 alkyl group, a C6-C30 alkenyl group, and C6-C30 is It may represent an alkynyl group, a C6-C30 aryl group, or a C6-C30 heterocyclic group, and may have a substituent further, n is 1 when L is a single bond, and when L is a bivalent or more coupling group (L is the mantissa-1)

In the organic acid represented by the said General formula (1), the peelability from a solution film forming installation (metal support body when casting dope) can be improved by the said X part which is an acidic group.

Further, the X moiety, which is an acidic group, is attached to the metal surface of the support, and the R ¹ moiety, which is a hydrophobic group of a specific structure, blocks the metal surface of the support from an oxidizing agent such as oxygen, thereby leaving an organic acid having a hydrophobic group that deviates from the range of R ¹ . In comparison with this, metal corrosion can be prevented.

Hereinafter, the peeling accelerator which can be used for the film of this invention is demonstrated.

In General formula (1), X represents the acid whose acid dissociation constant is 5.5 or less, A carboxyl group, a sulfonic acid group, a sulfinic acid group, a phosphoric acid group, a sulfonimide group, an ascorbic acid group are preferable, A carboxyl group and a sulfonic acid group are more preferable, and a carboxyl group is the most desirable. Moreover, when X represents an ascorbic acid group, it is preferable that the hydrogen atom of the 5th and 6th positions among the hydrogen atoms of ascorbic acid separates and is connected to L.

In this specification, as an acid dissociation constant, the value of chemical manual and a Maruzen Corporation publication is employ | adopted.

In general formula (1), R <^1> represents a hydrogen atom, a C6-C30 alkyl group (you may have a substituent), an alkenyl group (you may have a substituent), an alkynyl group (you may have a substituent), an aryl group ( And a heterocyclic group (you may have a substituent) are shown. Halogen atom, aryl group, heterocyclic group, alkoxyl group, aryloxy group, alkylthio group, arylthio group, acyl group, hydroxyl group, acyloxy group, amino group, alkoxycarbonyl group, acylamino group, oxycarbonyl group, carbamoyl group as a substituent , Sulfonyl group, sulfamoyl group, sulfonamide group, sulfolyl group, carboxyl group and the like.

More preferably, R <^1> is a C8-C24 alkyl group, an alkenyl group, and an alkynyl group, Most preferably, they are a C10-C24 linear alkyl group and an alkenyl group.

It is preferable that L in General formula (1) is a bivalent or more coupling group obtained by combining a single bond or the bivalent or more coupling group obtained from the following unit group, or two or more units selected from the following unit group.

Units: -O-, -CO-, -N (-R ² )-(wherein R ² is an alkyl group having 1 to 5 carbon atoms), -CH = CH-, -CH (OH)-, -CH ₂ -,- SO _2- ,

[Formula 4]

In the formula (1) L is a single bond, a linking group (-COO-, -OCO-), or a linking group of the amide group derived from the ester group derived from - a (-CONR ^2, -NR ² CO-) as a partial structure It is especially preferable to have.

In addition, the L is may have a substituent in addition, the substituent is not particularly limited, as there does not include a substituent which the above R ¹ may have, particularly preferred is -OH.

Among these, it is more preferable that L is a linking group containing a group derived from glycerin.

As said L, it is specifically preferable that it is the following structures. However, below, p, q, and r show the integer of 1-40, respectively, It is preferable that it is 1-20, It is more preferable that it is 1-10, It is especially preferable that it is 1-6. Moreover, it is especially preferable that q is 2-4.

In addition, R <^3> contained in the specific example of said L is the same meaning as said R <^1> in the said General formula (1). That _{is, - (CH 2) p -CO} -O- (CH 2) q - (CH (OCO-R 3)) - (CH 2) _r -O- in the linking group of R ³ is in the interior of convenience L Only described, the linking group L means a part except R ³ . In short, in this case L is trivalent. In the general formula (1), XL- (R ¹ ) ₂ , where L is-(CH ₂ ) _p -CO-O- (CH ₂ ) _q- (CH (OCO-))-(CH ₂ ) _r -O-]. That is, the linking group L at this time is a trivalent linking group.

It is preferable that the said L and said X are couple | bonded with the ester bond or the amide bond, and it is more preferable that they are couple | bonded with the ester bond. Moreover, it is more preferable that ester bond and amide bond do not exist in said X.

It is preferable that said L and said R <^1> are couple | bonded with an ester bond, an ether bond, or an amide bond, It is more preferable that they are couple | bonded with an ester bond or an amide bond, It is especially preferable that they are couple | bonded with an ester bond. Moreover, it is more preferable that ester bond, ether bond, and an amide bond do not exist in said R <^1> .

The preferable specific example of the organic acid represented by the said General formula (1) is given below.

"fatty acid"

Myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, ricinonoic acid, undecanoic acid.

<< alkyl sulfuric acid >>

Myristyl sulfuric acid, cetyl sulfuric acid, oleyl sulfuric acid.

<< alkylbenzene sulfonic acid >>

Dodecylbenzenesulfonic acid, pentadecylbenzenesulfonic acid.

<< alkyl naphthalene sulfonic acid >>

Sesquibutylnaphthalenesulfonic acid, diisobutylnaphthalenesulfonic acid.

<< dialkyl sulfosuccinic acid >>

Dioctyl sulfosuccinic acid, dihexyl sulfosuccinic acid, dicyclohexyl succinic acid, diamyl sulfosuccinic acid, ditridecyl cyclosuccinic acid.

`` Some derivatives of polyvalent organic acids ''

It is preferable that the organic acid represented by the said General formula (1) is some derivative of polyhydric organic acid. In this specification, some derivatives of a polyhydric organic acid have the structure where one fatty acid molecule and the polyhydric organic acid ester-bonded to 1 molecule of polyhydric alcohol, and have a compound which has at least one unsubstituted acidic group derived from polyhydric carboxylic acid. In addition, in this specification, a fatty acid means an aliphatic monocarboxylic acid. That is, the fatty acid in this specification is not limited to what is called higher aliphatic, but also lower fatty acids of 12 or less carbon atoms, such as acetic acid and a propionic acid, are included.

It is preferable that some derivatives of the said polyhydric organic acid are some derivatives of polyhydric carboxylic acid. That is, the organic acid represented by the said General formula (1) has a structure in which 1 fatty acid molecule and 1 polyhydric carboxylic acid ester-bonded to 1 molecule of polyhydric alcohols, and at least 1 unsubstituted carboxyl group derived from polyhydric carboxylic acid. It is desirable to have. Although it does not specifically limit as polyhydric carboxylic acid used for some derivatives of the said polyhydric carboxylic acid, For example, succinic acid, citric acid, tartaric acid, diacetyl tartaric acid, malic acid, adipic acid is preferable.

Examples of the polyhydric alcohol used in some derivatives of the polyvalent organic acid include adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, galactitol, mannitol, 3-methylpentane-1 , 3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylol ethane, xylitol, glycerin and the like. Especially, glycerin is preferable and it is preferable that the organic acid represented by the said General formula (1) is what is called organic acid glyceride.

The organic acid represented by the general formula (1), the acidic group X of an organic acid via a linking group L comprises a group of the glycerol derived from the organic acid glycerides (glycerol fatty acid ester) that is combined with a small number of part R ¹ is preferred. Here, with the organic acid glyceride in this specification, one or two of the three hydroxyl groups of glycerin make an ester bond with a fatty acid, and one or two of the remaining hydroxyl groups make an ester bond with a polyvalent organic acid, and the polyvalent organic acid The compound of the structure which has an derived acidic group is said.

Especially, organic acid monoglyceride or organic acid diglyceride is more preferable, and organic acid monoglyceride is especially more preferable. In the present specification, the organic acid monoglyceride is one of three hydroxyl groups of glycerin, which forms an ester bond with a fatty acid, and one or two of the remaining hydroxyl groups form an ester bond with a polyvalent organic acid, and the acid group derived from the polyvalent organic acid. The compound of having a structure is said. In the present specification, the organic acid diglyceride is a compound having a structure in which two of three hydroxyl groups of glycerin form an ester bond with a fatty acid, and one of the remaining hydroxyl groups forms an ester bond with a polyvalent organic acid, and the polyhydric organic acid has an acid group. Say

Of the organic acid monoglycerides, one of the three hydroxyl groups of glycerin makes an ester bond with a fatty acid, one of the remaining hydroxyl groups is an unsubstituted hydroxyl group, and one of the other hydroxyl groups makes an ester bond with a polyvalent organic acid, the polyvalent organic acid derived It is especially preferable that it is a compound of the structure which has an acidic group of. It is preferable that the hydroxyl group ester-bonded with the fatty acid of the said organic acid monoglyceride is an asymmetric position (so-called a position of (alpha) monoglyceride), and the hydroxyl group ester-bonded with the polyhydric organic acid of the said organic acid monoglyceride is the same asymmetric position (so-called position of α monoglyceride). That is, among the said organic acid monoglycerides, it is a compound of the structure which has an unsubstituted hydroxyl group, and the carbon atom which the direct carbon atom of the hydroxyl group ester-bonded with a fatty acid, and the direct carbon atom of the hydroxyl group ester-bonded with a polyhydric organic acid do not adjoin. It is preferable.

Among the organic acid monoglycerides, monoglycerides of polyhydric carboxylic acids are particularly preferred. The monoglyceride of the said polyhydric carboxylic acid means the organic acid in which at least 1 has an unsubstituted carboxyl group in polyhydric carboxylic acid, and the other carboxyl group is substituted by the monoglyceride. That is, the carboxyl group-containing organic acid monoglyceride which 1 molecule of fatty acids and 1 molecule of polyhydric carboxylic acid couple | bonded with 1 molecule of glycerin is especially preferable.

Although it does not specifically limit as said polyhydric carboxylic acid used for the monoglyceride of the said polyhydric carboxylic acid, For example, succinic acid, citric acid, tartaric acid, diacetyl tartaric acid, malic acid, adipic acid is preferable.

Although the said fatty acid used for the monoglyceride of the said polyhydric carboxylic acid is not limited, C8-C22 saturated or unsaturated fatty acid is preferable, Specifically, caprylic acid, capric acid, lauric acid, and myristic Acids, palmitic acid, stearic acid, behenic acid, oleic acid and the like.

Below, the carboxyl group-containing organic acid monoglyceride which can be used for this invention is demonstrated in detail.

The carboxyl group-containing organic acid monoglycerides that can be used in the present invention are generally reacted by reacting anhydrides of polyhydric organic acids with fatty acid monoglycerides according to the methods described in JP-A-4-218597, JP 3823524, and the like. Obtained.

The reaction is usually carried out under solvent-free conditions. For example, in the reaction between succinic anhydride and a fatty acid monoglyceride having 18 carbon atoms, the reaction is completed at about 120 ° C. for about 90 minutes. The organic acid monoglyceride thus obtained is usually a mixture containing organic acid, unreacted monoglyceride, diglyceride, and other oligomers. In this invention, you may use as such a mixture.

In order to improve the purity of the carboxyl group-containing organic acid monoglyceride, the carboxyl group-containing organic acid monoglyceride in the mixture as described above may be purified by distillation or the like, and as the carboxyl group-containing organic acid monoglyceride having high purity, it is commercially available as distilled monoglyceride. I can use it. As a commercial item of the said carboxyl group-containing organic acid monoglyceride, copper poem K-37V (glycerin citric acid oleate ester), step SS (glycerin stearic acid / palmitic acid succinic acid ester) manufactured by Cao Corporation, etc. are mentioned, for example.

The addition amount of the organic acid represented by the said General formula (1) contained in the film of this invention is 0.1 mass%-20 mass% with respect to the said cellulose acylate, It is especially preferable that they are 0.5 mass%-10 mass%, It is especially preferable that they are 0.6 mass%-5 mass%, and it is especially more preferable that they are 1.5 mass%-5 mass%.

A polarizer durability improvement effect and peelability improvement effect become enough that addition amount is 0.1% or more. Moreover, if it is the addition amount of 20 mass% or less, organic acid does not bleed out well in the passage of high temperature, high humidity time, and the orthogonal transmittance of a polarizing plate does not rise easily, and it is preferable.

It is preferable that the molecular weight of the organic acid represented by the said General formula (1) is 200-1000.

(Ester ester compound)

- sugar residue -

The sugar ester compound refers to a compound in which at least one of the substitutable groups (eg, hydroxyl group, carboxyl group) in the polysaccharide constituting the compound and at least one substituent group are ester-bonded. That is, the sugar ester compound mentioned here also includes the sugar derivatives of a broad meaning, For example, the compound containing a sugar residue, such as gluconic acid, as a structure is included. In other words, the sugar ester compound includes an ester of glucose and a carboxylic acid and an ester of gluconic acid and an alcohol.

It is preferable that the substitutable group in the polysaccharide which comprises the said sugar ester compound is a hydroxyl group.

In the said sugar ester compound, the structure (henceforth a sugar residue) derived from the polysaccharide which comprises a sugar ester compound is contained. The structure of the monosaccharide of the said sugar residue is called the structural unit of a sugar ester compound. It is preferable that the structural unit of the said sugar ester compound contains a pyranose structural unit or a furanose structural unit, and it is more preferable that all the sugar residues are a pyranose structural unit or a furanose structural unit. Moreover, when the said sugar ester consists of polysaccharides, it is preferable to include both a pyranose structural unit or a furanose structural unit.

Although the sugar residue of the said sugar ester compound may be derived from 5 monosaccharides or may be derived from 6 monosaccharides, it is preferable that it is derived from 6 monosaccharides.

It is preferable that it is 2-4, as for the number of the structural units contained in the said sugar ester compound, it is more preferable that it is 2-3, and it is especially preferable that it is two. That is, it is preferable that the sugar which comprises the said sugar ester compound is a disaccharide-a tetrasaccharide, It is more preferable that it is a disaccharide-a trisaccharide, It is especially preferable that it is a disaccharide.

In this invention, it is more preferable that the said sugar ester compound is a sugar ester compound containing 2-4 pyranose structural units or furanose structural units in which at least 1 of hydroxyl groups was esterified, and in a hydroxyl group More preferably, at least one is a sugar ester compound comprising two esterified pyranose structural units or two furanose structural units.

Examples of the monosaccharide or a saccharide comprising 2 to 4 monosaccharide units include, for example, erythrose, treose, ribose, arabinose, xylose, riseose, allose, altrose, glucose, fructose. Lactose, Mannose, Gulose, Idoose, Galactose, Taloose, Trehalose, Isotrehalose, Neotrehalose, Trehalosamine, Cozibiose, Nigerose, Maltose, Maltitol, Isomaltose , Sophorose, Laminaribiose, Cellobiose, Genthiobiose, Lactose, Lactosamine, Lactitol, Lactulose, Melibiose, Primeberose, Lutinose, Silaviose, Sucrose, Sucralose, Turanose , Bicyanos, cellotlios, cacotrios, gentianos, isomaltrios, isophanose, maltotriose, manninotriose, meletchiose, panos, plantos, raffinose,Eilat Rios, Titanium Valley Perot agarose, and the like Rico tetrahydro agarose, malto-tetra-Osu, stachyose, trehalose Balto penta, suberic to coarse, malto-hexahydro agarose, xylitol, sorbitol.

Preferably, ribose, arabinose, xylose, lyose, glucose, fructose, mannose, galactose, trehalose, maltose, cellobiose, lactose, sucrose, sucralose, xylitol, sorbitol , More preferably, arabinose, xylose, glucose, fructose, mannose, galactose, maltose, cellobiose, sucrose, and particularly preferably xylose, glucose, fructose, mannose, galactose , Maltose, cellobiose, sucrose, xylitol, sorbitol.

Preferable examples of the substituent of the sugar ester compound include an alkyl group (preferably an alkyl group having 1 to 22 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, particularly preferably an alkyl group having 1 to 8 carbon atoms, for example, a methyl group, an ethyl group, and a propyl group). Group, hydroxyethyl group, hydroxypropyl group, 2-cyanoethyl group, benzyl group, etc., aryl group (preferably C6-C24, more preferably 6-18, Especially preferably, 6-12 aryl Groups, for example, a phenyl group, a naphthyl group, an acyl group (preferably a C1-C22, more preferably a C2-C12, especially preferably an C2-C8 acyl group, for example, an acetyl group, Propionyl group, butyryl group, pentanoyl group, hexanoyl group, octanoyl group, benzoyl group, toluyl group, phthalyl group, etc.), an amide group (preferably C1-C22, more preferably C2-C12, especially preferably Is carbon number 2-8 amides, such as formamide group, acetamide group, etc., imide group (preferably C4-C22, More preferably, C4-C12, Especially preferably, C4-C8 amide group For example, a succinimide group, a phthalimide group, etc. are mentioned. Especially, an alkyl group or an acyl group is more preferable, a methyl group, an acetyl group, and a benzoyl group are more preferable, it is especially preferable that it is at least one of a benzoyl group and an acetyl group, and a benzoyl group is especially more preferable.

Although the specific example of the sugar ester compound which can be used for this invention is given to the following, this invention is not limited to this. Moreover, although the ester substitution degree of each sugar ester compound is not described in the following specific example, even if it uses as a sugar ester compound mixture using the sugar ester compound of arbitrary ester substitution degree, unless it contradicts the meaning of this invention. do.

[Chemical Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

[Chemical Formula 9]

In the following structural formulae, R represents an arbitrary substituent each independently, and some R may be same or different.

[Formula 10]

[Formula 11]

[Chemical Formula 12]

In addition, as said sugar ester compound, the sugar described in Unexamined-Japanese-Patent No. 2001-247717, Unexamined-Japanese-Patent No. 2005-515285, International Publication WO2007 / 125764, International Publication WO2009 / 011228, International Publication WO2009 / 031464, etc. Ester compounds can also be used.

As a method for obtaining the sugar ester compound, a commercially available ester derivatization method can be obtained commercially from Tokyo Chemical Co., Ltd., Aldorich Co., Ltd., or commercially available carbohydrates (e.g. By the method described in Japanese Patent Application Laid-Open No. Hei 8-245678).

As for the said sugar ester compound, the number average molecular weight becomes like this. Preferably it is 200-3500, More preferably, it is 420-3000, Especially preferably, the range of 450-2000 is preferable.

It is preferable to contain 2-30 mass% with respect to a cellulose acylate, and, as for the said sugar ester compound, it is more preferable to contain 5-20 mass%.

[Production Method of Film]

The film of this invention is a case where cellulose acetate is used as a cellulose acylate by the manufacturing method (henceforth a manufacturing method of this invention) of the film of this invention mentioned below in detail, and a cellulose butyrate or cellulose propio. When using a nate, it can manufacture efficiently by employ | adopting different film forming conditions according to each.

When cellulose acetate is used as a cellulose acylate, the manufacturing method of this invention is a process of solution-casting the dope containing the cellulose acetate of total acyl substitution degree 2.1-2.8 on a metal support body, and obtaining a film, and the said film a metal support body From the step of peeling to residual volatile matter H1 satisfying the following formula (i), the step of stretching the peeled film to 5 to 100% in the film conveying direction in the state of residual volatile matter H2 satisfying the following formula (ii), Including the process of extending | stretching 20 to 150% of the peeled film in the direction orthogonal to a film conveyance direction in the state of residual volatile matter H3 which satisfy | fills following formula (i), The said extending process satisfy | fills following formula (i) It features.

Formula (i) 20% ≤ H1 ≤ 60%

Formula (ii) 10% ≤ H2 ≤ 60%

Formula (VIII) 5% ≤ H3 ≤ 45%

Formula (i) (MD draw ratio + 100%) / (TD draw ratio + 100%) ≥ 0.70

(In formula, MD draw ratio shows the draw ratio (unit:%) to a film conveyance direction, TD draw ratio shows the draw ratio (unit:%) to the direction orthogonal to a film conveyance direction.)

In the case where cellulose butyrate or cellulose propionate is used as the cellulose acylate, a step of solution-casting a dope containing cellulose butyrate or cellulose propionate with a total acyl substitution degree of 2.1 to 2.8 on a metal support to obtain a film; The film is peeled from the metal support with residual volatile matter H1 satisfying the following formula (i), and the peeled film is 20 to 100% in the film conveying direction in the state of residual volatile matter H2 satisfying the following formula (ii). The process of extending | stretching and the process of extending | stretching a peeled film 35-150% in the direction orthogonal to a film conveyance direction in the state of residual volatile matter H3 which satisfy | fills following formula (iii), The said extending process is a following formula (ⅳ It is characterized by satisfying

Formula (i) 20% ≤ H1 ≤ 60%

Formula (ii) 10% ≤ H2 ≤ 60%

Formula (VIII) 5% ≤ H3 ≤ 45%

Formula (i) (MD draw ratio + 100%) / (TD draw ratio + 100%) ≥ 0.70

(In formula, MD draw ratio shows the draw ratio (unit:%) to a film conveyance direction, TD draw ratio shows the draw ratio (unit:%) to the direction orthogonal to a film conveyance direction.)

Hereinafter, the manufacturing method of this invention is demonstrated.

<Step of Forming Cellulose Acylate in Film Shape>

In the manufacturing method of this invention, in the process of forming a cellulose acylate into a film form, the solution casting film forming method may be used, or the melt film forming method may be used. Especially, it is preferable to use the solution casting film forming method, and it is more preferable to use the method of casting the dope containing a cellulose acylate and a solvent on a support body. Moreover, in the manufacturing method of this invention, it is especially preferable that dope is cast on a support body, and a solvent is evaporated and a cellulose acylate film is formed.

(Preparation of Dope)

In the manufacturing method of this invention, each component preferable to be contained in dope is demonstrated. However, it is preferable that 3 mass% or more of Re expression agents are not contained with respect to the said cellulose butyrate or cellulose propionate. About other additives, it can use preferably in the range illustrated in description of the film of this invention, and there is no restriction | limiting in particular also about the addition time to dope.

In the dope used for this invention, it is preferable to adjust the amount of cellulose acylate so that 10-40 mass% may be contained in dope obtained. The amount of cellulose acylate is more preferably 10 to 30 mass%.

If the solvent used in dope in the manufacturing method of this invention is a solvent used for solution casting | flow_spread, a well-known thing can be employ | adopted, From a viewpoint of reducing haze more, Ether of 3-12 carbon atoms, 3 carbon atoms It is preferable to contain the solvent chosen from the ketone of -12, the ester of 3-12 carbon atoms, and the halogenated hydrocarbon of 1-6 carbon atoms. The ether, ketone and ester may have a cyclic structure. The compound which has two or more of functional groups (that is, -O-, -CO-, and -COO-) of an ether, a ketone, and ester can also be used as a solvent. The solvent may have other functional groups, such as an alcoholic hydroxyl group. In the case of the solvent which has two or more types of functional groups, the carbon atom number should just be in the prescribed range of the compound which has any 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. Included.

Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclohexanone 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. It is preferable that halogen of halogenated hydrocarbon is chlorine. It is preferable that it is 25-75 mol%, It is more preferable that it is 30-70 mol%, It is still more preferable that it is 35-65 mol%, The ratio in which the hydrogen atom of halogenated hydrocarbon is substituted by halogen is 40-60 mol% Is most preferred. Examples of halogenated hydrocarbons include dichloromethane, chloroform, methyl chloride, carbon tetrachloride, trichloroacetic acid, methyl bromide, methyl sulfide, tri (tetra) chloroethylene, and the like, and preferably at least dichloromethane.

In this invention, it is also preferable to contain a poor solvent in the ratio of 3-30 weight%, and it is more preferable to contain in the ratio of 5-20 weight%. By containing a poor solvent within the said range, compatibility with a cellulose acylate improves and haze tends to fall further, and it is preferable.

Moreover, it is preferable that the boiling point of a poor solvent is 120 degrees C or less, It is more preferable that it is 40-100 degreeC, The drying rate of a solvent can be made faster by making a boiling point 120 degrees C or less, and it is preferable. As such a poor solvent, methanol, ethanol, propanol, butanol, and water are mentioned as a preferable example, and methanol is more preferable.

The said dope can be prepared by a general method. The general method means processing at a temperature of 0 ° C. or higher (normal temperature or high temperature). The solution can be prepared by using a method and apparatus for preparing dope in a conventional solvent casting method. Dope can be prepared by stirring a cellulose acylate and a 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 solvent are put in a pressurized container to be 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 the solvent. Heating temperature is 40 degreeC or more normally, Preferably it is 60-200 degreeC, More preferably, it is 80-110 degreeC.

You may mix each component previously, and may put in a container (tank etc.). Moreover, you may input to a 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. Moreover, you may use the vapor pressure raise of a solvent by heating. Or after sealing a container, you may add each component 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 providing a plate heater in the exterior of a container, piping, and circulating a liquid.

It is preferable to form a stirring blade inside a container, and to stir using this. It is preferable that the stirring blade is a length reaching near the wall of the container. It is preferable to form a scraper blade at the end of the stirring blade in order to update the liquid film of the container wall.

Instruments may be provided with instruments such as a pressure gauge and a thermometer. 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 cooled using a heat exchanger or the like.

The said dope can also be prepared by a cooling dissolution method.

(Film forming process)

In this invention, it is preferable to manufacture a cellulose acylate film from the prepared dope by the solvent cast method.

As the method and equipment for producing the film of the present invention, the same solution casting film forming method and solution casting film forming apparatus as those used for conventionally producing cellulose triacetate film are used. The dope (cellulose acylate solution) prepared from the dissolver (kiln) is once stored in a storage kiln, and the air bubbles contained in the dope are defoamed to make final preparation. The pressurization die which can adjust the slit shape of the die | dye part of die | dye, and is easy to make film thickness uniform is preferable. There exist a coat hanger die, a T die, etc. in pressurization die | dye, and all are used preferably. The surface of the metal support is mirror-finished. In order to increase the film forming speed, two or more press dies may be formed on the metal support, and the amount of the dope may be divided into a middle layer. Alternatively, it is also preferable to obtain a laminated film by a covalent bonding method in which a plurality of doughs are simultaneously flexible.

The dope is sent from the dope outlet to a pressurized die through a pressurized metering gear pump capable of metering and feeding with high precision at a rotational speed, for example, and the dope is running endlessly from the detention (slit) of the pressurized die. It is preferable to peel off a less dry dope film (also called a web) from a metal support at the peeling point which is uniformly flexible on the metal support of a casting part, and the metal support is almost round. Both ends of the web to be obtained are sandwiched with a clip, conveyed by a tenter and dried, then conveyed by a roll group of a drying apparatus to complete drying, and wound up to a predetermined length by a winder. The combination of a tenter and a drying apparatus of a roll group changes with the objective. In the solution casting film forming method used for the functional protective film for electronic displays, in addition to the solution casting film forming apparatus, a coating device may be added for surface processing on films such as an undercoat layer, an antistatic layer, an antihalation layer, a protective layer, and the like. many. Although each manufacturing process is briefly described below, it is not limited to these.

The prepared dope is cast on an endless metal support, for example, on a metal drum or a metal support (band or belt), and the solvent is evaporated to form a film. It is preferable that the dope before casting | flow_spread adjusts density | concentration so that a cellulose amount may be 10-35 mass%. It is preferable to finish the surface of a drum or a band in a mirror surface state. As for the casting and drying method in the solvent cast method, U.S. Pat.Nos.2336310, 2367603, 2492078, 2492977, 2492978, 262607704, 2739069, and 2739070, British Patent No. 640731, each specification of No. 73,896, Japanese Patent Publication Nos. 45-4554, 49-5614, 60-176834, 60-203430, 62 Each publication of -115035 is described.

In addition, Japanese Unexamined Patent Publication No. 2000-301555, Japanese Unexamined Patent Publication No. 2000-301558, Japanese Unexamined Patent Publication No. Hei 7-032391, Japanese Unexamined Patent Publication No. 3-193316, Japanese Unexamined Patent Application Publication No. 5-086212, Japan Each of Unexamined-Japanese-Patent No. 62-037113, Unexamined-Japanese-Patent No. 2-276607, Unexamined-Japanese-Patent No. 55-014201, Unexamined-Japanese-Patent No. 2-111511, and Unexamined-Japanese-Patent No. 2-208650. The cellulose acylate film forming technique described in the publication can be applied in the present invention.

It is preferable that dope is cast | flow_spread on the drum or band whose surface temperature is 30 degrees C or less, and it is especially preferable that it is a metal support temperature of -50-20 degreeC. It is preferable that the manufacturing method of this invention blows dry air from both the back surface and the surface of the said metal support body with respect to the said dope cast on the said metal support body. It is preferable to let it dry for 2 seconds or more after it is soft. The obtained film may be peeled off from the drum or the band, and further dried by hot air having a temperature changed sequentially from 100 ° C 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.

In the production method of the present invention, it is preferable that, as the dope, each dope is co-lead on the support using two or more kinds of dope having different total acyl substitution degrees of cellulose acylate.

In the formation of the film of the present invention, it is preferable to use a lamination casting method such as a co-combustion method, a sequential casting method, a coating method, and the like, and in particular, it is particularly preferable from the viewpoint of stable manufacturing and production cost reduction.

In the case of producing by the common method and the continuous casting method, first, a cellulose acetate solution (dope) for each layer is prepared. The co-combustion method (medium-layer simultaneous casting) is used to remove the dope from a casting base that simultaneously extrudes each casting layer (may be three or more layers) onto the casting support (band or drum) from a separate slit or the like. It is a casting | flow_spread method which is extruded, each layer is cast | flow_spread simultaneously, peels from a support body at an appropriate time, and it dries and shape | molds a film.

The sequential casting method first extrudes the casting dope for the first layer from the casting base and casts it on, or does not dry, the extrusion dope for the second layer from the casting base. In order to cast | flow, it is a casting | flow_spread method of carrying out casting | flow_spreading and laminating | stacking to a 3rd layer or more sequentially, peeling from a support body at an appropriate time, drying, and shape | molding a film. In general, the coating method is to form a film of a core layer into a film by a solution film forming method, to prepare a coating liquid to be applied to the surface layer, and to coat and dry the coating liquid to the film one by one or both sides simultaneously using a suitable applicator. It is a method of shape | molding the film of a laminated structure.

(Peeling)

It is a process of peeling the web in which the solvent evaporated on the metal support body in a peeling position. The peeled web is sent to the next process. In addition, when the residual volatile matter (following formula) of the web at the time of peeling is too large, it is difficult to peel, or, on the contrary, if the film is peeled off after being sufficiently dried on a metal support, part of the web may peel off in the middle.

Here, there is a gel casting method (gel casting) as a method of increasing the film forming speed (the film forming speed can be increased by peeling as much of the residual solvent amount as possible). For example, there is a method of adding a poor solvent to cellulose acylate in dope, gelling after dope casting, lowering the temperature of the metal support, and gelling. By gelling on a metal support and increasing the film strength at the time of peeling, peeling can be advanced and film forming speed can be raised.

Although the amount of residual solvent at the time of peeling of a web on a metal support body peels in the range of 5-150 mass% according to the strength and dryness of a dry condition, the length of a metal support, etc., when an amount of residual solvent peels in more time, it is economical The balance of speed and quality determines the amount of residual solvent at the time of peeling. In this invention, it is preferable to make temperature in the peeling position on the said metal support body into -50-40 degreeC, 10-40 degreeC is more preferable, and it is most preferable to set it as 15-30 degreeC.

The manufacturing method of this invention includes the process of peeling the said film from the metal support body with residual volatile matter H1 which satisfy | fills following formula (VII) irrespective of the kind of cellulose acylate.

Formula (i) 20% ≤ H1 ≤ 60%

It is preferable that said H1 is 22 to 55%, and it is especially preferable that it is 25 to 45%.

The residual solvent amount can be represented by the following formula.

Residual solvent amount (mass%) = {(M - N) / N} 100

Here, M is mass at arbitrary time points of a web, and N is mass when the thing of mass M is dried at 110 degreeC for 3 hours.

(Tension control by dancer mechanism)

In the manufacturing method of this invention, when forming the said cellulose acylate into a film form, it uses a flexible film forming apparatus, and uses the dancer mechanism between peeling the said film from the said flexible film forming apparatus and before the said extending process. It is more preferable to include the process of controlling the tension | tensile_strength applied to a film from a viewpoint of improving the dispersion | variation in the slow-axis orientation of a film longitudinal direction. The tension control by the dancer mechanism means controlling to maintain a constant amount of tension applied to the film by the dancer mechanism having the dancer roller.

Although the tension control by the dancer mechanism in this invention is not specifically limited to the following aspects, In the manufacturing method of this invention, the web (film) dried and peeled on the drum or the belt is shown before FIG. 2, it is preferable to carry it through the roll group arrange | positioned as FIG. 2, and to convey the tension | tensile_strength applied to a film, driving a dancer mechanism variably so that the fluctuation from a preferable specific center value may not become large. Moreover, although it is preferable that the tension control part by such a dancer mechanism is formed in front of the apparatus which performs an extending process, it may be before or after a drying process. Especially, when using a tenter method in the extending process mentioned later, it is preferable to dry a film smoke film, carrying out fixed drive, holding both ends of a film with a tenter, ie, drum or a band of a film forming apparatus. It is preferable to let the tension control part by a dancer mechanism pass in the film smoke film state after peeling from before a drying process.

As such a dancer mechanism, a well-known apparatus can be used, and the dancer mechanism 10 of FIG. 1 and FIG. 2 is mentioned especially. 2 is a schematic diagram of a dancer mechanism 10 that can be preferably used in the present invention. The dancer mechanism 10 includes a dancer roller 11, guide rollers 17a and 17b, a load control device (dancer load control unit) 13 that controls the weighting of the dancer roller 11, and a dancer roller. It consists of the angle detector (dancer position detection sensor) 12 which detects the position of 11. The dancer roller 11 is attached so that the guide roller 17a, 17b can move freely in the up-down direction in the figure. And the magnitude | size of the tension applied to the film (web) smoke film 24 peeled from the peeling drum 21 is determined according to the magnitude | size of the weight loaded on the dancer roller 11.

It is preferable that the magnitude | size of the tension applied to the film (web) smoke film 24 peeled from the peeling drum 21 exists in the range of 0-300N. Moreover, it is preferable that the fluctuation | variation of the magnitude | size of tension applied to the film (web) smoke film peeled from the peeling drum 21 is the center value +/- 30N or less of set tension.

In addition, the load control method may be (1) load control by an air cylinder, or (2) any method of putting a weight on the opposite side to the side which contact | connects a film to up-down may be controlled.

In FIG. 2, the position of the dancer roller 11 is detected by the angle detector (dancer position detection sensor) 12. And as a method of response control of the dancer roller 11 based on this position detection result, (1) the method of increasing / decelerating tenter drive when a dancer raises and falls may be used, and (2) lightens the load on a dancer. Any method may be sufficient. For example, the dancer roller 11 uses a conveying speed in a process subsequent to the dancer mechanism (for example, a tenter device in the stretching step) so that the dancer roller 11 is held at an intermediate position between the movable upper limit position and the lower limit position. In the case of conveying and extending | stretching while holding a film, the tenter drive speed) can be increased and decreased and controlled. For example, when the dancer roller 11 moves from the neutral position to the lower limit direction, the dancer roller 11 can be returned to the neutral position by increasing the tenter driving speed.

The film peeled from the drum or band of a flexible film forming apparatus becomes soft, so that the temperature is high. Therefore, in this invention, it is preferable to make temperature of a dancer part into the range of 25-100 degreeC, and the tension magnitude | size which hangs on the film (web) smoke film 24 peeled from the peeling drum 21 within such a temperature range. It is preferable to set the magnitude of the weight to be loaded on the dancer roller 11 so that the variation is within the range of the center value ± 30 N or less of the set tension.

The surface temperature of the film (web) smoke film 24 peeled from the peeling drum 21 is arrange | positioned between the peeling drum 21 and the dancer mechanism 10, and is connected to the probe for temperature measurement which measures the surface temperature of a film. Measured by the temperature sensor 14. In addition, as a probe for temperature measurement, as long as it does not damage the surface of the film in conveyance, you may use the probe of arbitrary shape and a material. In addition, in this invention, the position of the temperature sensor 14 of FIG. 2 is not limited to this, For example, you may arrange | position it in the other position of the upstream of the dancer mechanism 10. As shown in FIG.

The control of each part of the tension control unit by the above dancer mechanism is performed by a system controller (not shown). As a system controller, the thing of the stage of Unexamined-Japanese-Patent No. 2005-306019 can be used, for example, and it can collectively control the operation | movement of a film manufacturing facility. The system controller (not shown) includes, for example, a drive motor (not shown), a tension sensor 15, a load control device 13, an angle detector 12, a warm air control unit (not shown). ), A temperature sensor 14, an operation panel (not shown), and the like are connected. The system controller controls the load control device 13 for the dancer based on the set tension value input through the operation panel (not shown), and loads the weight on the dancer roller 11, and the angle detector. Based on the position detection result by 12, a drive motor (not shown) can be controlled and the drive speed of the tenter apparatus 23 can be adjusted so that the dancer roller 11 may be maintained at a preferable position. In addition, the system controller can control the warm air control unit (not shown) based on the film surface temperature detection result by the temperature sensor 14 to adjust the temperature of the warm air sprayed from the air blow (not shown).

In addition, although the tension control part by such a dancer mechanism is formed in one point on the film conveyance path | route in FIG. 1, this invention is not limited to such an aspect, You may form two or more points according to the length of a conveyance path | route. Moreover, as described in Unexamined-Japanese-Patent No. 2005-306019, the dancer mechanism may be used together with a suction drum, for example.

The drying method of the web dried and peeled on a drum or a belt is described. The web peeled off at the peeling position just before the drum or the belt is rounded is alternately passed through the roll group arranged in a zigzag shape and conveyed, or the method of gripping both ends of the peeled web with a clip or the like and conveying it in a non-contact manner. It is preferable to be conveyed.

In the manufacturing method of this invention, in the moving part from the said peeling process to the said extending process, it is preferable that the said film passes 3 or more pass rolls of at least 60 degrees of wrap angles, and it passes through 5 or more pass rolls. More preferably, it is especially preferable to pass through 7 to 51 pass rolls. Moreover, it is preferable that the manufacturing method of this invention contains at least 1 dancer as said pass roll of 60 degrees or more of said lap angles, and it is preferable that one said dancers is one. In addition, the dancer mentioned here also includes the guide roll of 17a or 17b of FIG. 2, and the path | pass of at least 60 degrees or more of lap angles between the guide roll 17a and the extending | stretching apparatus 23 in FIGS. 1 and 2 is shown. It is preferable to pass more than the number of rolls mentioned above. In addition, the lap angle in this specification means the magnitude | size of the center angle which connects the arc center and the roll center which the film wraps a roll, for example, the wrap angle in the case where a film passes the roll arrange | positioned in perfect zigzag shape. Is 180 degrees.

Drying is performed by the method of making wind of predetermined temperature apply to both surfaces of the web (film) in conveyance, the method of using heating means, such as a microwave. Since rapid drying may impair the planarity of the film formed, in the initial stage of drying, it is preferable to dry at a temperature such that the solvent does not foam, and to carry out drying at a high temperature after drying proceeds. In the drying step after peeling from the support, the film tends to shrink longitudinally or widthwise by evaporation of the solvent. Shrinkage becomes large as it dries at high temperature. Drying while suppressing this shrinkage as much as possible is preferable in order to improve the planarity of the finished film. In this regard, for example, as disclosed in Japanese Patent Application Laid-Open No. 62-46625, a method of carrying out the entire process or part of the drying process while maintaining both ends of the width of the web with a clip or pin in the width direction. (Tenter system) is preferable. It is preferable that the drying temperature in the said drying process is 100-145 degreeC. Although drying temperature, dry air volume, and drying time differ according to the solvent used, what is necessary is just to select suitably according to the kind and combination of solvents used.

In the manufacturing method of this invention, extending | stretching to the direction orthogonal to the said film conveyance direction is performed by a tenter, and it is preferable from a viewpoint of the standard deviation reduction of the slow axis orientation of a film longitudinal direction to satisfy following formula (i). .

Formula (ⅴ) W × 30 ≥ L ≥ W × 2

(In formula, L represents the distance (unit: mm) to the said tenter in the said peeling process, W represents the width (unit: mm) of the peeled film.)

As for the manufacturing method of this invention, it is more preferable to satisfy Wx28≥L≥Wx2.5, and it is especially preferable to satisfy Wx25≥L≥Wx3.

(Drawing step)

In manufacture of the film of this invention, the process of extending | stretching the web (film) peeled from a support body is included. Since the preferable range differs when (1) cellulose acetate is used as cellulose acylate and (2) cellulose butyrate or cellulose propionate is used as cellulose acylate, it demonstrates in order below.

(1) When cellulose acetate is used as cellulose acylate

When the cellulose acetate is used as a cellulose acylate, the manufacturing method of this invention is a process of extending | stretching 5 to 100% in a film conveyance direction in the state of residual volatile matter H2 which satisfy | fills following formula (ii), and peeling 20 to 150% of the stretched film in a direction orthogonal to the film conveying direction in the state of residual volatile matter H3 satisfying the following formula (i), wherein the stretching step satisfies the following formula (i) It is done.

Formula (ii) 10% ≤ H2 ≤ 60%

Formula (VIII) 5% ≤ H3 ≤ 45%

Formula (i) (MD draw ratio + 100%) / (TD draw ratio + 100%) ≥ 0.70

(In formula, MD draw ratio shows the draw ratio (unit:%) to a film conveyance direction, TD draw ratio shows the draw ratio (unit:%) to the direction orthogonal to a film conveyance direction.)

When cellulose acetate is used as a cellulose acylate, it is preferable that it is 5 to 25%, and, as for the draw ratio in extending | stretching to a film conveyance direction, it is more preferable that it is 8 to 22%.

In addition, "stretch ratio (%)" here means what is calculated | required by the following formula | equation.

Stretch ratio (%) = 100 × {(length after stretching)-(length before stretching)} / length before stretching

There is no restriction | limiting in particular in the method of extending | stretching a web to a film conveyance direction. For example, a method of providing a circumferential speed difference to a plurality of rolls and stretching in the longitudinal direction using a roll circumferential speed therebetween, fixing both ends of the web with clips or pins, The method of extending | stretching a longitudinal direction and extending | stretching to a longitudinal direction, or the method of extending | stretching longitudinally and simultaneously simultaneously and extending | stretching in both longitudinal and horizontal directions, etc. are mentioned. Of course, you may use these methods in combination. In addition, in the so-called tenter method, when the clip portion is driven by the linear drive method, stretching can be performed smoothly, which is preferable because the risk of breaking or the like can be reduced. Stretching to the said longitudinal direction uses the apparatus which has two nip rolls, and makes cellulose acylate to a conveyance direction (vertical direction) by making the rotation speed of the nip roll of an exit side faster than the rotation speed of the nip roll of an inlet side. It is preferable to extend a film. By performing such extending | stretching, the expression property of retardation can also be adjusted.

Moreover, at this time, it is preferable that it is 20 to 55%, and, as for said H2, it is more preferable that it is 25 to 50%.

When there is too much residual volatile content in a web, the effect of extending | stretching will not be acquired, and when too small, extending | stretching will become difficult remarkably and breakage of a web may occur.

In the manufacturing method of this invention, it is preferable to extend | stretch extending | stretching in the state with a tension fluctuation value less than 10 N / m, extending | stretching to the said film conveyance direction, It is more preferable to control to less than 8 N / m, More preferably, 0 N / It is especially preferable to control by m-6 N / m.

When using cellulose acetate as a cellulose acylate, it is preferable that it is 15 to 60%, and, as for the draw ratio in extending | stretching in the direction orthogonal to a film conveyance direction, it is more preferable that it is 20 to 50%.

There is no restriction | limiting in particular in the method of extending | stretching a web in the direction orthogonal to a film conveyance direction. For example, the both ends of a web are fixed with a clip or a pin, the method of extending a space | interval of a clip or a pin in a transverse direction, and extending | stretching in a transverse direction, or the method of extending | stretching in both a longitudinal and a transverse direction simultaneously. Of course, you may use these methods in combination. In addition, in the so-called tenter method, when the clip portion is driven by the linear drive method, stretching can be performed smoothly, which is preferable because the risk of breaking or the like can be reduced. In this invention, it is preferable to extend | stretch using a tenter apparatus as a method of extending | stretching in the direction orthogonal to a film conveyance direction.

Moreover, it is preferable at this time that said H3 is 8 to 40%, and it is more preferable that it is 10 to 35%.

When there is too much residual volatile content in a web, the effect of extending | stretching will not be acquired, and when too small, extending | stretching will become difficult remarkably and breakage of a web may occur.

The manufacturing method of this invention can improve a film elastic modulus by controlling draw ratio so that MD draw ratio and TD draw ratio may satisfy | fill following formula (i).

Formula (i) (MD draw ratio + 100%) / (TD draw ratio + 100%) ≥ 0.70

(In formula, MD draw ratio shows the draw ratio (unit:%) to a film conveyance direction, TD draw ratio shows the draw ratio (unit:%) to the direction orthogonal to a film conveyance direction.)

Moreover, when extending | stretching in a film width direction, distribution may generate | occur | produce in the refractive index in width. Although this may be seen, for example, when the tenter method is used, it is a phenomenon caused by the contraction force generated in the film center portion by stretching in the width direction, and the end portion is fixed. Also in this case, by extending | stretching to a casting | flow_spread direction, a bowing phenomenon can be suppressed and the phase difference distribution of width can be improved little. Moreover, the film thickness variation of the film obtained by extending | stretching in the biaxial direction orthogonal to each other can be reduced. When the film thickness variation of a cellulose acylate film is too big | large, it will become a deviation of a phase difference. It is preferable to make the film thickness variation of a cellulose acylate film into the range of +/- 3% and +/- 1%. Also for the above purposes, the method of extending | stretching in the biaxial direction orthogonal to each other so that Formula (i) may be satisfied is effective.

In the manufacturing method of this invention, extending | stretching temperature is Te + 30 degrees C or less, provided

Drawing temperature ≤ Te + 30 ℃ (Ⅰ)

Te = T [tanδ]-ΔTm (II)

ΔTm = Tm (0)-Tm (x) (III)

(In formula (II), T [tanδ] represents the temperature at which tanδ shows a peak when the dynamic viscoelastic tanδ of the cellulose acylate when the amount of residual solvent is 0%, and Tm (0) represents 0% of the residual solvent amount. The crystal melting temperature of the cellulose acylate at the time of, and Tm (x) represents the crystal melting temperature of the cellulose acylate when the amount of residual solvent with respect to the cellulose acylate is x%). Hereinafter, extending | stretching in such a temperature range is also called low temperature stretching. By extending | stretching the film formed in the film form at low temperature, Rth expressability can be improved without making the film thickness of the film of this invention thick, ie, Rth (550) / d can be made higher and it is preferable. Although not bound by any theory, since the orientation of the polymer or the additive in the stretching is less likely to occur in the above-described low temperature stretching, Re can be expressed without lowering Rth. As for the said extending | stretching temperature, it is more preferable that it is Te-30-Te degreeC. Even when extending | stretching in a film conveyance direction, even if extending | stretching in a film width direction, the preferable range is the same.

(2) When cellulose butyrate or cellulose propionate is used as cellulose acylate

The manufacturing method of this invention WHEREIN: When using a cellulose butyrate or a cellulose propionate, the process of extending | stretching the peeled film by 20 to 100% in a film conveyance direction in the state of residual volatile matter H2 which satisfy | fills said Formula (ii), and And extending | stretching the peeled film in the direction orthogonal to a film conveyance direction in the state of residual volatile matter H3 which satisfy | fills the said Formula (VII), The said extending process satisfy | fills said Formula (VII) It is characterized by.

When cellulose butyrate or cellulose propionate is used as a cellulose acylate, it is preferable that it is 20 to 60%, and, as for the draw ratio in extending | stretching to a film conveyance direction, it is more preferable that it is 25 to 45%.

When using cellulose butyrate or cellulose propionate as a cellulose acylate, it is preferable that it is 38 to 80%, and, as for the draw ratio in extending | stretching in the direction orthogonal to a film conveyance direction, it is more preferable that it is 40 to 60%. .

In addition, when cellulose butyrate or cellulose propionate is used as a cellulose acylate, the preferable range of other extending | stretching conditions is the same as the case where cellulose acetate is used as a cellulose acylate.

(Heat treatment process)

The manufacturing method of the film of this invention may provide the heat processing process mentioned above after completion | finish of a drying process. The heat treatment in the heat treatment step may be carried out after the completion of the drying step, may be performed immediately after the stretching / drying step, or may be separately provided only after the winding step is completed by the method described later after the drying step is completed.

Heat processing is performed by the method of making the film | membrane in conveyance wind the predetermined temperature, the method of using heating means, such as a microwave.

It is preferable to perform heat processing at the temperature of 150-200 degreeC, and it is more preferable to carry out at the temperature of 160-180 degreeC. Moreover, it is preferable to perform heat processing for 1 to 20 minutes, and it is more preferable to carry out for 5 to 10 minutes.

(Winding)

The winding machine generally used can be used for the winding machine which winds up the obtained film, and can be wound up by winding methods, such as a static tensioning method, the static torque method, the taper tensioning method, and a program tension control method with a constant internal stress. . In the cellulose acylate film roll obtained as mentioned above, it is preferable that the slow-axis direction of a film is +/- 2 degree with respect to a winding direction (the longitudinal direction of a film), and it is more preferable that it is the range of +/- 1 degree. Or it is preferable that it is +/- 2 degree with respect to the direction orthogonal to the winding direction (width direction of a film), and it is more preferable to exist in the range of +/- 1 degree. It is preferable that especially the slow-axis direction of a film is within +/- 0.1 degree with respect to the winding direction (the longitudinal direction of a film). Or it is preferable that it is within ± 0.1 degree with respect to the width direction of a film.

(Residue volatile)

The cellulose acylate film obtained by the method for producing a film of the present invention described above is preferably 1% by mass or less and 0.2% by mass or less in the residual volatile content of the final finish film, in order to obtain a film having good dimensional stability.

Moreover, the manufacturing method of this invention may include the process of manufacturing a film, detecting the slow-axis orientation of a film longitudinal direction inline. The preferable aspect in that case is the same as the aspect mentioned above as a method of obtaining in-line the standard deviation of the slow-axis orientation of the film longitudinal direction of the film of this invention.

<Polarizer>

The polarizing plate of this invention contains a polarizer and the cellulose acylate film of this invention. It is characterized by the above-mentioned.

Since the film optical characteristic is favorable and film elasticity is also favorable, the film of this invention is used suitably for the protective film for polarizing plates. Moreover, since the film of this invention has favorable surface shape and there is little variation when the film surface shape is observed under polarizing plate cross nicol, it is suitable for the protective film for polarizing plates. A polarizing plate is formed by bonding a protective film to at least one surface of a polarizer, and laminating | stacking. A polarizer can use what is known conventionally, For example, it extends | stretches by treating a hydrophilic polymer film like a polyvinyl alcohol film with a dichroic dye like iodine. Although bonding of a cellulose acylate film and a polarizer does not have limitation in particular, It can carry out by the adhesive agent which consists of aqueous solution of a water-soluble polymer. As this water-soluble polymer adhesive, the fully saponified polyvinyl alcohol aqueous solution is used preferably.

Moreover, the polarizing plate using the film of this invention has little variation in slow-axis distribution, and can provide the liquid crystal display device of favorable display performance. In addition, when the film of this invention is a preferable aspect of a wide width | variety, when bonding with a polarizer using the film of this invention and manufacturing a polarizing plate, what is called 2 pieces and 3 pieces of what is called a polarizing plate is performed in a film width direction. It becomes possible and can reduce the manufacturing cost of a polarizing plate. Moreover, when (sigma) 600 and (sigma) -600 of a film width direction are also a favorable aspect, the performance of the polarizing plate which performed two pieces and three pieces can also be improved.

<Liquid Crystal Display Device>

The liquid crystal display device of this invention contains a cellulose acylate film or the polarizing plate of this invention, It is characterized by the above-mentioned.

The film of this invention is a structure of the protective film for polarizing plates, the protective film for polarizing plates, the polarizing plate, the protective film for liquid crystal cells, the film, polarizer, polarizing plate of this invention, or the protective film for polarizing plates, and the film / liquid crystal cell of this invention. / It can use suitably with the structure of the protective film for polarizing plates of this invention, the polarizer / protective film for polarizing plates. In particular, by bonding to a liquid crystal cell such as a TN type, a VA type, or an OCB type, it is possible to provide a liquid crystal display device having excellent viewing angle, little coloration, excellent visibility, and excellent in-plane uniformity. Moreover, the polarizing plate using the film of this invention has little deterioration under high temperature, high humidity conditions, and can maintain stable performance for a long time, ie, the liquid crystal display device of this invention is also favorable in durability.

Example

Hereinafter, the present invention will be described in more detail with reference to examples. The materials, the amounts to be used, the ratios, the contents of the treatments, the processing procedures, and the like shown in the following examples can be appropriately changed as long as they do not depart from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples.

Example 1: Film formation of cellulose acylate film

(2) dope preparation

<1-1> cellulose acylate solution

The following composition was put into a mixing tank, stirred to dissolve each component, and heated at 90 ° C. for about 10 minutes, and then filtered through a filter paper having an average pore diameter of 34 μm and a sintered metal filter having an average pore diameter of 10 μm.

<1-2> Matte dispersion

Next, the following composition containing the cellulose acylate solution prepared by the above method was introduced into a disperser to prepare a dispersion of a mat agent.

<1-3> additive solution

The cellulose acylate solution prepared by the above method was put into a mixing tank, stirred to dissolve while heating, and each additive described in Table 6 was added to prepare an additive solution. Moreover, each additive is demonstrated below. Additives A-C are the compositions shown in Table 5 below. In Table 5, EG represents ethylene glycol, PG represents propylene glycol, BG represents butylene glycol, TPA represents terephthalic acid, PA represents phthalic acid, AA represents adipic acid, and SA represents succinic acid.

Compound D represents the retardation expression agent of the following structure.

Compound D

[Chemical Formula 13]

The compound E shows the poem K-37V by Riken Vitamin Co., Ltd. which is a peeling promoter.

Compound U represents the retardation expression agent of the following structure.

Compound u

[Formula 14]

Compound T represents TPP / BDP (1/1, mass ratio).

In Example 6 using CAP, Compound X having the following structure was used as the additive.

Compound X

[Formula 15]

100 mass parts of the said cellulose acylate solution, 1.35 mass part of the mat dispersion, and the said additive solution were mixed, and the dope for film forming was prepared.

In addition, the cellulose acylate used as a raw material of dope, and various additives used what was previously dried at 120 degreeC using the silo manufactured by Nara Machinery Co., Ltd. for 2 hours.

Here, in the following Table 6, an alphabet shows the kind of each additive, and a numerical value shows an addition amount. In addition, the addition ratio of the said additive solution is a ratio in which the addition amount (mass part) of each additive when the amount of cellulose acylate is 100 mass parts becomes a value shown in following Table 6.

(softness)

Only the Examples 5, 6, 7, and Comparative Examples 7 and 8 were plied by the metal band softener 20 which is the installation which has the dancer mechanism described in FIG. 1 and FIG. All of them were flexible with the same film making machine except that they did not have a dancer function. Air supply temperature of 80 degreeC-130 degreeC (exhaust temperature is 75 degreeC-120 degreeC) from both the back surface and the surface of a band, and after drying by blowing dry air, residual volatile matter is H1 (mass in Table 6 below). %), The film was peeled from the band by the peeling drum 21.

Before the longitudinal stretching and the lateral stretching were performed by the stretching apparatus 23, the dancer mechanism 10 including the dancer roller 11 was passed through. Film formation is performed, controlling the temperature of the dancer part in the temperature sensor 14 of FIG. 2 so that the tension with respect to the film in 50 degreeC and the tension sensor 15 may be set to 200 N / m, and the tension shown in Table 6 is carried out. It was driven while controlling the load by the load control device 13 and the angle detector 12 of the dancer mechanism 10 so as to be a variation. After passing the guide roll 17b, 15 pass rolls 18 of 60 degree or more of lap angles were passed, and the film was introduce | transduced into the extending | stretching apparatus 23. At this time, the distance L to the tenter in the peeling step was 15000 mm, the width W of the peeled film was 1900 mm, and W x 30? L? W x 2 was satisfied.

(Stretching)

Then, when it was residual solvent density | concentration H2 of following Table 6, it extended | stretched in the tenter zone by fixed edge uniaxial stretching in the film conveyance direction at 130 degreeC by MD draw ratio shown in following Table 6. At this time, the variation of the tension at the time of MD stretching was measured by tension pickup, and it is shown in following Table 6.

Next, when it was residual solvent concentration H3, it extended | stretched in the tenter zone by fixed edge uniaxial stretching in the film width direction at 160 degreeC by the TD draw ratio of Table 6 below, and produced the cellulose acylate film. Moreover, MD / TD draw ratio was calculated | required and it is shown in following Table 6. At this time, the casting film thickness was adjusted so that the film thickness after extending | stretching and drying might become the film thickness of following Table 7.

In order to manufacture the film of the composition shown in following Table 6, and to judge the manufacture suitability, the roll of 1980 m roll and 2000 m roll length was produced at least 24 rolls on the said conditions. The sample (length 1980mm) of length 1m was cut out at 100m interval with respect to 1 roll of 24 rolls continuously manufactured. This was used as the cellulose acylate film of Example 1.

[Examples 2 to 10 and Comparative Examples 1 to 13]

As shown in following Table 6, except having changed the used cellulose acylate resin, the additive, and film manufacturing conditions, it carried out similarly to Example 1, and obtained the cellulose acylate film of each Example and a comparative example. In Example 10, three-layer covalent lead was performed in the order of the outer layer dope, the core layer dope, and the outer layer dope from the support side.

<Measurement method>

(Film optical characteristics)

The in-plane retardation Re is determined by three-dimensional birefringence measurement at a wavelength of 550 nm using the automatic birefringence meter KOBRA-WR (manufactured by Oji Meter Co., Ltd.) by the method described above, and the retardation Rth in the film thickness direction is It calculated | required by changing Re and measuring Re.

Moreover, the measurement wavelength was changed into 450 nm and 630 nm, the value of Re (450) and Re (630) was measured, and wavelength dispersion (DELTA) Re = Re (630) -Re (450) was calculated.

In addition, the obtained value of Rth (unit: nm) was divided by the film thickness d (unit: nm) of each film, and Rth and Rth / d per film thickness were calculated | required.

Their results are shown in Table 7 below.

(Standard deviation of slow axis deviation of film longitudinal end (σ600, σ-600)

The slow-axis deviation standard deviation (sigma) 600 and (sigma) -600 of the film longitudinal direction edge part were measured with the following method.

The sample film was conveyed at 20 m / min, controlling the deviation of the vertical up-down direction of a film between 2 mm or less between the pass rolls parallel-paralleled within 0.5 mm. On a line 600 mm away from the center line in the film width direction in one direction and the other film end direction, every 6 mm at 33 mm (measured at 0.1 second intervals) over 2000 m in the film conveying direction (length direction), respectively. The slow axis orientation was measured. Their average values were determined and the standard deviations sigma 600 and sigma -600 of slow axis deviations were calculated by calculation.

In addition, about the other measurement conditions of standard deviation (sigma) 600 and (sigma) -600 of the slow-axis orientation of a film longitudinal direction, it set as follows, and detected and calculated by the following method.

Device: High Speed Retardation Measuring Device Re100 OTSUKA Electronics Co., Ltd.

Measuring length: 2000 m

Measurement pitch: Continuous measurement every 0.1 s at 20 m / min conveyance

About 60000 points of data,

(Where x _i is each slow axis angle deviation and n is 60000). Variance σ

Respectively.

The obtained result was evaluated based on the following criteria.

(Double-circle): (sigma) 600 or (sigma) -600 is 0.08 or less.

(Circle): (sigma) 600 or (sigma) -600 is 0.10 or less.

(Triangle | delta): (sigma) 600 or (sigma) -600 is 0.13 or less.

▲: sigma 600 or sigma-600 is 0.15 or less.

X: sigma 600 or sigma -600 is larger than 0.15.

The obtained results are shown in Table 7 below.

(Film elastic modulus)

A sample 10 mm x 150 mm (TD x MD) was moistened at 25 ° C and 65% relative humidity for 2 hours, using an universal tensile tester STM T50BP manufactured by Toyo Baldwin, at 23 ° C in an atmosphere of 60% relative humidity. The stress deformation curve was measured by extending | stretching process to MD direction to sample length 50mm and 10% / min, and the film elastic modulus E '(MD) (unit: Mpa) of MD direction was calculated | required. Similarly, using 150 mm x 10 mm (TD x MD) of the sample, the extending | stretching process was performed in the TD direction on the same conditions, and the film elastic modulus E '(TD) (unit: MPa) of the TD direction was calculated | required. Moreover, E '(TD) / E' (MD) was computed from the elasticity modulus in each obtained direction.

In addition, E '(TD) was measured in 19 samples for every 100 mm of width. These average values were calculated | required and the standard deviation (sigma) (unit: kPa) of the elasticity modulus E '(TD) in a film width direction was calculated | required from the following method.

For the 19 data obtained,

Calculated by (where x _i is the deviation of each E '(TD) and n is 19). Variance σ

Respectively.

The obtained results are shown in Table 7 below.

(Panel performance)

[Production of Polarizing Plate]

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

The cellulose acylate film of Example 1 subjected to saponification was affixed to one side of the polarizer using a polyvinyl alcohol-based adhesive. The same saponification process was performed to the commercially available cellulose triacetate film (Fuji-Tak TD80UF, Fujifilm Co., Ltd. product), and the side with which the polarizing plate protective film of Example 101 which was manufactured using the polyvinyl alcohol-type adhesive agent is stuck. Attached a cellulose triacetate film after saponification to the surface of the polarizer on the opposite side.

Under the present circumstances, the transmission axis of a polarizer and the slow axis of the polarizing plate protective film of Example 1 manufactured were arrange | positioned so that it might become parallel. Moreover, the transmission axis of a polarizer and the slow axis of a commercially available cellulose triacetate film were arrange | positioned so that it may cross.

Thus, the polarizing plate of Example 1 was manufactured.

[Manufacture of Liquid Crystal Display Device]

About the obtained polarizing plate, it bonded together to the following panel.

Evaluation evaluated the liquid crystal display device in each Example and a comparative example which used the said polarizing plate about the thing which remove | eliminated the front side and the rear side polarizing plate (henceforth a panel) from the liquid crystal display of Sharp Corporation LC-42DS6. It was. In addition, the panel size was 1025 mm x 673 mm.

(1) viewing angle color taste (contrast in oblique direction)

Using a measuring instrument (BM5A, manufactured by TOPCON), the luminance values of the black display and the white display in the polar directions 60 degrees and the azimuth directions 0 degrees, 45 degrees, and 90 degrees in the dark room were measured. The viewing angle characteristics of the liquid crystal display device were evaluated by calculating the viewing angle contrast (white luminance / black luminance).

(Circle): All viewing angle contrasts are 60 or more, and light leakage cannot be recognized.

(Triangle | delta): The minimum value of viewing angle contrast is less than 60 and 30 or more, and light leak is recognized slightly but an acceptable degree.

X: The viewing angle contrast minimum value is less than 30, and large light leakage is recognized and cannot be tolerated.

The column which shows the evaluation result of the viewing angle contrast in the following table | surface evaluates with the said reference | standard about the said 3 directions, and shows the average result.

The obtained results are shown in Table 7 below.

(2) durability evaluation

Each liquid crystal display device was left to stand in 50 degreeC and the thermostat of 95% of a relative humidity for 500 hours, and it lighted after taking out. Thereafter, using a measuring device (BM5A, manufactured by TOPCON), the viewing angle contrast in the polar angle direction 60 degrees and the azimuth direction 45 degrees from the front of the device was measured in the dark room. The viewing angle contrast before and after continuous lighting was compared, and durability was evaluated based on the following references | standards.

(Double-circle): The difference of viewing angle contrast is less than five.

(Circle): The difference of viewing angle contrast is 5 or more and less than 10 (the light leakage after continuous lighting is small and the tolerance is acceptable).

X: The difference in viewing angle contrast is 10 or more (large light leakage is recognized and cannot be allowed after continuous lighting).

The obtained results are shown in Table 7 below.

(3) panel in-plane uniformity

In each of these Examples and Comparative Examples, white display was performed on the panel of the liquid crystal display device, and the luminance was measured every 10 mm in-plane using a BM-5 luminance meter manufactured by Topcon Corporation. Next, black display was performed and luminance was measured every 10 mm of in-planes using the BM-5 luminance meter by Topcon Corporation.

T white / T black was defined as contrast, with the luminance at the time of white display being T white and the luminance at the time of black display T black.

The homogeneity of the obtained panel was evaluated based on the following criteria.

(Double-circle): The dispersion | variation in contrast in panel surface is less than 3%.

(Circle): The deviation of contrast in panel surface is within 5%.

(Triangle | delta): The deviation of contrast in the inside of a panel is 10% or less.

▲: The variation in contrast within the panel plane is within 15%.

X: The deviation of contrast in the inside of a panel is 20% or less.

The results obtained in the above evaluations are shown in Table 7 below.

From Table 7, all of the cellulose acylate films of the present invention have reverse wavelength dispersion having ΔRe> 0 nm, and are excellent in the expression of retardation in the film thickness direction per film thickness, the elastic modulus in the film longitudinal direction is large, and in the width direction It was found that the variation in the modulus of elasticity was small, and the in-plane uniformity when it was attached to the polarizing plate and combined with the panel was good.

Moreover, the liquid crystal display device using the film of this invention was all favorable in viewing angle color taste and durability.

On the other hand, Comparative Example 1 and 10 are the aspect which did not perform TD extending | stretching, and it turned out that the obtained film has a bad elasticity modulus and has a problem in panel surface uniformity. Comparative Examples 2 and 3 are aspects which followed the structure similar to the Example of Unexamined-Japanese-Patent No. 2006-030962. In Comparative Example 2, cellulose acylate butyrate was used to add 5% by mass of additive U which is a retardation expression agent, and the MD stretching ratio and the TD stretching ratio deviate from the ranges defined by the production method of the present invention, and the reverse wavelength It did not disperse | distribute and was also bad in elasticity modulus, and when attached to the liquid crystal display device, it turned out that there is a problem in viewing angle color taste and panel in-plane uniformity. In Comparative Example 3, the TD draw ratio was increased in the range of the present invention without adding the additive U in Comparative Example 2, but the MD draw ratio deviated from the range defined by the production method of the present invention, and the film per film thickness The expression of retardation in the thickness direction was inferior, and the elasticity modulus was also bad, and it turned out that there is a problem in panel in-plane uniformity when it attaches to a liquid crystal display device.

Comparative Examples 4-6 are similar to the Example of Unexamined-Japanese-Patent No. 2009-263619, and are the aspect which did not extend | stretch in the MD direction, and since both are inferior in film optical characteristic or film elastic modulus, it mounts in a liquid crystal display device It turned out that there is a problem in panel in-plane uniformity.

Comparative Examples 7 and 8 are embodiments in which 5 mass% of additive U which is a retardation expression agent is used, and in the case of Comparative Example 7 in which the total acyl substitution degree and MD draw ratio of cellulose acylate are outside the range of the production method of the present invention, the film thickness The expression of retardation in the film thickness direction of the sugar and the elastic modulus in the MD direction were inferior, and it was found that there was a problem in the in-plane uniformity when mounted on the liquid crystal display device. Moreover, in the case of the comparative example 8 which made MD draw ratio into the range of the manufacturing method of this invention, and only total acyl substitution degree of cellulose acylate was out of the range of the manufacturing method of this invention, reverse wavelength dispersion does not become a liquid crystal display device. It was found that there was a problem in viewing angle color taste and panel in-plane uniformity when it was attached to.

The comparative example 9 is an aspect using the cellulose acylate below the range of the total substitution degree of the cellulose acylate of this invention, when the expression property and film elastic modulus of the retardation of the film thickness direction per film thickness fall, and when attached to the liquid crystal display device, It was found that there was a problem in the in-plane uniformity of the panel.

In Comparative Example 11, the draw ratio ratio between MD stretching and TD stretching was outside the range of the production method of the present invention, and it was found that the obtained film had a low film elastic modulus and had problems in panel in-plane uniformity when attached to a liquid crystal display device. there was.

In Comparative Examples 12 and 13, the residual volatile matter at the time of film forming was outside the range of the production method of the present invention, and in Comparative Example 12, the film was broken. Moreover, in Comparative Example 13, it was found that the resulting film had a poor expression and film elastic modulus in the retardation in the film thickness direction per film thickness, and thus had problems in panel in-plane uniformity when attached to the liquid crystal display device.

10: dancer equipment
11: dancer (dancer roller pass pass roll. Movable, non-moving material)
12: angle detector
13: load control device
14: temperature sensor
15: tension sensor
16: film conveyance direction
17a, 17b: guide roll (part of pass roll)
18: pass roll
20: band softener
21: peeling drum
22: dope
23: drawing device
24: Film (Web) Smokescreen

Claims (25)

As a cellulose acylate film containing the cellulose acylate of total acyl substitution degree 2.1-2.8,
Carbon number of the acyl group of the said cellulose acylate is 2-4,
The cellulose acylate film contains at least one of a polycondensation ester and a sugar ester,
The elasticity modulus of the film conveyance direction of the said cellulose acylate film is 3200 Mpa or more,
The variation of the elasticity modulus of the film width direction of the said cellulose acylate film is 0.5 kPa or less,
The following formula (1)-(3) is satisfied, The cellulose acylate film characterized by the above-mentioned.
Equation (1) 0 nm ≤ ΔRe ≤ 15.0 nm
(DELTA Re represents the value (unit: nm) which subtracted the value of in-plane retardation in wavelength 450nm from the value of retardation of the in-plane direction in wavelength 630nm.)
(2) 2 × 10 ^-3 ≤ Rth / d ≤ 6 × 10 ^-3
(In formula, Rth represents the value (unit: nm) of retardation of the film thickness direction in wavelength 550nm, d shows the film thickness (unit: nm).)
Equation (3) 1.0 ≤ E '(TD) / E' (MD) ≤ 1.43
(In formula, E '(MD) shows the elasticity modulus (unit: Mpa) of a film conveyance direction, E' (TD) shows the elastic modulus (unit: MPa) of a film width direction.) The method of claim 1,
The elasticity modulus of a film conveyance direction is 3500 Mpa or more, The cellulose acylate film characterized by the above-mentioned. The method of claim 1,
The retardation value Re of the in-plane direction in wavelength 590 nm, and the retardation value Rth of the film thickness direction in wavelength 590 nm satisfy | fill the following formula, The cellulose acylate film characterized by the above-mentioned.
35 nm ≤ Re ≤ 80 nm, 100 nm ≤ Rth ≤ 300 nm The method of claim 1,
The cellulose acylate is cellulose acetate, characterized in that the cellulose acylate film. The method of claim 1,
The organic acid represented by following General formula (1) is contained, The cellulose acylate film characterized by the above-mentioned.
In general formula (1)
XL- (R ¹ ) _n
(In the formula (1), X is the acid dissociation constant of 5.5 or less represents a substituent containing an acidic group, L is a single bond or a represents a more linking group, R ¹ is an alkyl group having 6 to 30 carbon atoms, having 6 to 30 carbon atoms It may represent an alkenyl group, a C6-C30 alkynyl group, a C6-C30 aryl group, or a C6-C30 heterocyclic group, and may have a substituent further, n is 1 when L is a single bond, and L is When these two or more coupling groups are (the valence of L-1)) The method of claim 5, wherein
R <^1> in the said General formula (1) represents a C6-C24 alkyl group, a C6-C24 alkenyl group, or a C6-C24 alkynyl group (however, you may further have a substituent), It is characterized by the above-mentioned A cellulose acylate film made into. The method of claim 5, wherein
X in the said General formula (1) has at least 1 group chosen from the group which consists of at least 1 carboxyl group, a sulfonic acid group, a sulfinic acid group, a phosphoric acid group, a sulfonimide group, and an ascorbic acid group, The cellulose acylate characterized by the above-mentioned. film. The method of claim 5, wherein
L in the said General formula (1) is a single bond or the coupling group obtained by combining the 2 or more units selected from the following unit group, or 2 or more units selected from the following unit group, The cellulose acylate film characterized by the above-mentioned.
Units: -O-, -CO-, -N (R ² )-(wherein R ² represents an alkyl group having 1 to 5 carbon atoms), -OH, -CH = CH-, -CH (OH)-, -CH _2- , -SO _2- ,
[Formula 1]

The method of claim 5, wherein
The organic acid represented by the general formula (1) is formed by combining one molecule of a fatty acid and one molecule of a polyvalent carboxylic acid with one molecule of a polyhydric alcohol, and further has at least one unsubstituted carboxyl group derived from the polyvalent carboxylic acid. A cellulose acylate film made into. The method of claim 5, wherein
The molecular weight of the organic acid represented by the said General formula (1) is 200-1000, The cellulose acylate film characterized by the above-mentioned. The method of claim 1,
Has a laminated structure of two or more layers,
A cellulose acylate film, wherein the average total acyl substitution degree of the cellulose acylate contained in each layer is different from each other. The method of claim 1,
The deviation standard deviation ((sigma)) of the slow-axis orientation in a film width direction edge part is 0.10 or less, The cellulose acylate film characterized by the above-mentioned. The polarizing plate using the cellulose acylate film of any one of Claims 1-12. The liquid crystal display device using the cellulose acylate film of any one of Claims 1-12.
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