KR101530805B1 - Stretched cellulose ester film and method for producing same - Google Patents

Abstract

Disclosure of the Invention Problems to be Solved by the Invention It is an object of the present invention to provide a cellulose acylate film which is capable of suppressing disturbance of the cellulose orientation even when the film is stretched at a high magnification, Stretched cellulose ester film and a method for producing the same. The stretched cellulose ester film of the present invention contains a cellulose ester having an acetyl group substitution degree within a range of 2.8 to 2.95, wherein a part of the cross-sectional shape of the stretch cellulose ester film in the width direction of the A- And the film thickness difference h (film maximum film thickness - film terminal film thickness) is in the range of 1.0 to 4.0 占 퐉. Here, the A side refers to a side opposite to a side contacting the belt surface or the drum surface when the belt dough is flexible on the belt or drum to form the film dope.

Description

[0001] STRETCHED CELLULOSE ESTER FILM AND METHOD FOR PRODUCING SAME [0002]

The present invention relates to a stretched cellulose ester film and a method for producing the same.

2. Description of the Related Art In recent years, there has been a strong demand for a liquid crystal display (hereinafter also referred to as LCD) from the spread of a liquid crystal display for mounting on a car, a display of a large liquid crystal television, a cellular phone, Various optical films such as a polarizing film and a retardation film are used for such LCD.

Demand for LCDs is increasing, and a polarizing plate used in accordance with the demand is also required to be thinned, lightweight, and aged. In addition, along with the large display of an LCD, optical films as members are also required to have a thin film and widening accompanied with aging, and studies are being made to improve the film characteristics centered on mechanical strength properties.

The cellulose ester film is commercially available as a polarizing plate protective film. However, in the case of producing such a film having a thin film and a wide width, in order to adjust the optical properties and planarity and the film thickness and width of the obtained film, (For example, refer to Patent Document 1).

When the cellulose ester film is stretched at a high magnification in order to make it wider and thinner, in particular, when a film having a width exceeding 1.6 m is produced, disturbance is likely to occur in the cellulose orientation of the film portions due to stretching at a high magnification, It was found that the notch breakdown occurred or the breakage occurred in severe cases. In addition, fluctuations in the retardation value Ro in the in-plane direction, which is important in the optical characteristics, in the film portions are increased, resulting in problems in productivity and optical characteristics, and improvement has been desired.

Japanese Patent Application Laid-Open No. 2010-1383

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems and it is an object of the present invention to provide a method of manufacturing a multilayer ceramic capacitor which is capable of suppressing disturbance of the cellulose orientation even when it is widened by high- And a method for producing the stretched cellulose ester film.

DISCLOSURE OF THE INVENTION In order to solve the above-described problems, the present inventors have conducted intensive studies on the cause of the above problems, and have found that a stretched cellulose ester film containing cellulose ester having a specific acetyl group substitution degree, In the case of a structure having a specific film thickness difference in the plane, disturbance of the cellulose orientation can be suppressed even if elongation at a high magnification is carried out and the notch breakdown is hard to occur even at a high speed conveyance, It is possible to obtain a stretched cellulose ester film having a small fluctuation in the retardation in the direction of the stretched cellulose ester film. Thus, the present invention has been accomplished.

That is, the above-described problems related to the present invention are solved by the following means.

1. A stretched cellulose ester film comprising a cellulose ester having an acetyl group degree of substitution in a range of 2.8 to 2.95, wherein a part of a cross-sectional shape in the width direction of the stretched cellulose ester film is represented by a hanging curve, h (film maximum film thickness - film terminal film thickness) is in the range of 1.0 to 4.0 탆,
Wherein an average value of the arithmetic mean roughness (Ra) at the center of the stretched cellulose ester film on the side A is in the range of 2.2 to 3.5 nm and a value of the average value of the arithmetic mean roughness (Ra) of the edge on the side of the stretched cellulose ester film To 1.0 nm. ≪ RTI ID = 0.0 > 11. < / RTI >

Here, the A side refers to a side opposite to a side contacting the belt surface or the drum surface when the belt dough is flexible to form a film dope, and the end portion refers to the total width of the stretched cellulose ester film L means the end portion of the film to L x 0.05 and the central portion refers to a portion of 占 L 占 0.1 in the width direction from the center portion of the film when the total width of the stretched cellulose ester film is L. [

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3. The stretched cellulose ester film according to claim 1, wherein the stretched cellulose ester film has a width of 2 to 3 m and a maximum film thickness of 30 to 70 탆.

4. A process for producing the stretched cellulose ester film according to claim 1, wherein the dope for forming the stretched cellulose ester film is formed on a belt or a drum so that a part of a cross-sectional shape in the width direction of the film A- Characterized in that a stretching treatment is carried out while forming a web by softening and peeling and lowering the surface temperature of the end portion of the web on the side A in the range of 10 to 50 DEG C compared with the surface temperature of the central portion, Way.

When the total width of the unstretched cellulose ester film is taken as Lo, the end portion refers to the end portion of the film or the Lo × 0.05 portion. When the total width of the unstretched cellulose ester film is Lo, Quot; Lo x 0.1 "

Wherein at least one pair of cold air generating portions is provided for adjusting the surface temperature of the end portion, and cool air having a low temperature within a range of 10 to 50 DEG C, as compared with the temperature of the central portion, The stretched cellulose ester film according to claim 4, wherein the stretching treatment is carried out while spraying on the end portion.

6. The method according to claim 4 or 5, wherein the stretching is carried out in the film width direction at a stretching magnification in the range of 160 to 190 DEG C and in a range of 25 to 100% ≪ / RTI >

According to the present invention, even when stretching at a high magnification to widen the width, disturbance of the cellulose orientation is suppressed and even if the film is transported at a high speed, the notch failure hardly occurs and the fluctuation in retardation value Ro in the in- A stretched cellulose ester film and a process for producing the same.

The mechanism and mechanism for manifesting the effect of the present invention are not clarified, but are estimated as follows.

The conventional stretched cellulose ester film is designed and adjusted uniformly over the entire film. Especially when the width is 2 m or more, when the web is stretched at a high magnification and then transported at a high speed, the fluctuation of the web itself, , The notch failure tends to occur easily, and in severe cases, breakage occurs frequently.

By increasing the thickness from the end portion to the center portion of the film as in the stretched cellulose ester film of the present invention, the center of gravity of the film can be localized at the center portion. As a result, fluctuation of the web is suppressed even after high- And the occurrence of the notch failure can be suppressed.

It is also possible to suppress the disturbance of the orientation of the cellulose in the width direction at the time of stretching by localizing the center of gravity of the film at the center portion at the same time so that the stretch cellulose ester film Is obtained.

1 is a schematic view showing a cross-sectional shape of an oriented cellulose ester film of the present invention.
Fig. 2 is a schematic side view of the production apparatus for producing the stretched cellulose ester film of the present invention. Fig.
3 is a schematic planar view of a drawing apparatus (tenter);
4 is a schematic view of a stretched cellulose ester film of the present invention.
5 is a schematic diagram showing a preferred stretching treatment method in the present invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail, but the present invention is not limited thereto.

The stretched cellulose ester film of the present invention is a stretched cellulose ester film containing a cellulose ester having an acetyl group substitution degree in the range of 2.8 to 2.95, wherein a part of the cross-sectional shape in the width direction of the A- And the film thickness difference h (film maximum film thickness-film terminal film thickness) is in the range of 1.0 to 4.0 占 퐉. With this configuration, even if the high magnification drawing is carried out to widen the pitch, And the retardation value Ro in the in-plane direction of the stretched cellulose ester film is small.

Here, the A side refers to a side opposite to a side contacting the belt surface or the drum surface when the belt dough is flexible on the belt or drum to form the film dope.

This feature is a technical feature that is common to the claims of the claims 1 to 6. [

As an embodiment of the present invention, it is preferable that the average value of the arithmetic average roughness (Ra) of the central portion on the A-plane of the stretched cellulose ester film is in the range of 2.2 to 3.5 nm, and the stretched cellulose ester It is preferable that the average value of the arithmetic mean roughness (Ra) of the end portions in the film A surface is in the range of 0.3 to 1.0 nm in terms of suppressing fluctuation of the web at the time of high speed conveyance and enhancing the effect of the present invention.

It is preferable that the width of the stretched cellulose ester film is within a range of 2 to 3 m and the maximum film thickness of the film is within a range of 30 to 70 탆.

As a method for producing the stretched cellulose ester film of the present invention, there can be used a method in which the dope for forming the stretched cellulose ester film is stretched so that a part of the cross-sectional shape in the width direction of the A- The web is formed on a belt or a drum and the stretching process is carried out while the surface temperature of the end of the web on the side A is lowered in the range of 10 to 50 DEG C compared with the surface temperature of the center portion Can control the arithmetic mean roughness (Ra) of the center portion and the end portion within a preferable range, and the fluctuation of the web is suppressed even when the high-speed conveyance is performed after the high-magnification drawing is performed.

Further, at least one pair of cold air generating portions is provided for adjusting the surface temperature of the end portion, and cool air having a low temperature within a range of 10 to 50 DEG C, as compared with the temperature of the central portion, It is more preferable as an embodiment to perform drawing treatment while spraying on the end portion.

In order to obtain a stretched cellulose ester film having a wide width in the film width direction at a stretching magnification in the range of 160 to 190 캜 and in the range of 25 to 100% This is a preferred production method.

The suspension curve will be described later, but the cross-sectional shape in the width direction of the stretched cellulose ester film of the present invention is shown in FIG. 1 as a schematic diagram.

Each symbol in Fig. 1 represents F: stretched cellulose ester film, A: A side, B: B side, Mh: maximum film thickness, Lh: terminal film thickness, and K: hanging curve.

In the present invention, the cellulose ester film after stretching treatment is referred to as "stretched cellulose ester film", and the cellulose ester film before stretching treatment is referred to as "unstretched cellulose ester film" or "web".

The stretched cellulose ester film of the present invention is characterized in that a part of the cross-sectional shape in the width direction of the A side is represented by a hanging curve. As shown in Fig. 1, the stretched cellulose ester film has a gentle curve with respect to the film end, And has a thicker film thickness. The " part of the cross-sectional shape in the width direction of the A side " specifically means the cross-sectional shape in the width direction of the A side surface indicated by K in Fig.

Hereinafter, the present invention will be described in detail.

<Explanation of the Suspension Curve>

The suspension curve referred to in the present invention refers to a curve having one vertex and being line-symmetric with respect to the normal at the vertex as an axis.

The stretched cellulose ester film of the present invention is characterized in that a part of the cross-sectional shape in the width direction of the A side is expressed by a formula showing a hanging curve. As shown in Fig. 1, part of the cross-sectional shape of the A-plane in the width direction is convex upward, so that the film thickness h with respect to the width direction is expressed by the following equation (1) .

h = - (e ^a + e ^-a ) / 2 Equation (1)

Here, when the product width of the stretched cellulose ester film is x, a changes in the range of -x / 2? A? X / 2.

A part of the sectional shape in the width direction of the A side may be expressed by the formula (1), but in the present invention, the film thickness difference h (film maximum film thickness - film end film thickness) at the end portion and the central portion of the film is 1.0 to 4.0 If a more specific approximate expression is obtained by adding the condition that the product width x is in the range of 1.0 탆 (i.e., 1.0 10 ^-6 to 4.0 10 ^-6 (m)) and the product width x changes in the range of 2 to 3 m, The relation of the hinge curves for (2) is as follows.

h (m) = - (e a + e -a) / b Equation (2)

In the formula, a is -x / 2? A? X / 2 (m), and b is in the range of 3.0 x 10 ^5? B? 7.0 x 10 ⁵ . In the present invention, it is determined that a part of the cross-sectional shape with respect to the width direction of the A side is represented by a suspen- sion curve when expressed by the above formula (2).

In order to measure the film thickness in the transverse direction of the A-plane of the stretched cellulose ester film of the present invention, it is preferable to use a contact type film thickness meter (Micrometer Minicom M manufactured by Tokyo Seimitsu Co., Ltd.) The thickness can be determined by measuring at intervals. From the obtained film thickness value, it is possible to determine the regression equation of the film thickness variation with respect to the film width direction to determine whether it is expressed by the equation of the suspending curve.

&Lt; Film Formation Process >

In the present invention, a dope containing a cellulose ester and other additives is plied on a support (flexible process), then peeled off from the support (peeling process), the peeled web is subsequently stretched (stretched process) (Post-drying step), and the film is wound on a roller (winding step) to prepare an elongated cellulose ester film.

2, the apparatus for producing a cellulose ester film comprises a support 1 comprising a rotating metal endless belt, a die 2 for casting a dope as a raw material solution of a cellulose ester film on a support 1, A peeling roller 3 for peeling the web W formed on the support 1 by the die 2 from the support 1 and a film F peeled from the support 1 in the width direction A drying device 5 for drying the film F while conveying the film F via a plurality of conveying rollers 6 and a stretch cellulose ester film (for example, F which is wound around the take-up roller.

A slit process (ear notch) is provided between the tenter 4 and the drying device 5 or between the drying device 5 and the winding roller 8 to obtain a desired product film width. The slit device is provided at both left and right ends of the film, and the slit device is constituted by a disk-like rotating upper side blade and a roller-shaped lower rotating blade. When the stretched cellulose ester film is transported at high speed, if the shaking motion of the film is large, the slit section quality of the end portion is lowered in this step, and notch failure or breakage failure tends to occur.

2, before the stretching process by the tenter 4, the keeping step 4-1 is performed so that the temperature of the unstretched cellulose ester film Fo is not excessively lowered, After the step (1), a cooling step (4-2) for slow cooling the film is provided. Before the drying process by the drying device 5, the heat preservation step (5-1) and the drying device (5) (drying step) are performed so that the temperature of the stretched cellulose ester film (F) A cooling step (5-2) for performing slow cooling of the wafer W is provided.

<Flexible Process>

It is preferable that the softening process of the stretched cellulose ester film of the present invention is such that the filtered dope is fed to the pressure die through the pressure type metering gear pump and the dope is softened from the pressure die on the metal support at the flexible position. In order to make the cross-section (film thickness) with respect to the width direction of the A-surface surface to be represented by the suspension curves as in the present invention, a press die which is easy to change the flow rate in the flexible width direction is preferable. The pressure die may be a coat hanger die or a T die. Both are preferably used. In order to increase the film forming speed, two or more pressure dies may be provided on a metal support to divide the doping amount so as to form an intermediate layer.

Specifically, the film thickness control represented by the suspen- sion curve is carried out by controlling the dope concentration, the amount of the pump feed, the slit gap of the die cementing member, the die extrusion pressure, the speed of the metal support, Or by raising the temperature of the end portion so as to produce a difference in viscosity. It is preferable to control the film thickness at the time of softening such that the shape of the web surface is approximated to the hanging curve by simply adjusting the slit shape of the cementing member portion.

<Stretching Step>

An example of the mechanism of the tenter 4 is shown in Fig. 3, in the tenter 4, a plurality of clips 11 are connected in a chain state on both right and left side portions of the housing 10, and these clips 11 become one loop So that the unstretched cellulose ester film Fo is gripped and transported by running on the rail 12. Each of the clips 11 is provided with a pivotable pressing arm which is not shown in the drawing. Both widthwise ends of the unstretched cellulose ester film Fo on the pedestal on both sides of the tenter 4 are fixed to the tenter 4, (Clamped) between the curved front end of the pressing arm of the pressing arm of the pressing arm and the pedestal.

In the tenter 4, the unstretched cellulose ester film Fo is stretched in the film width-retaining zone A, the film width direction stretching zone B, And the width-retaining zone C, and stretched in the film width direction to obtain a stretched cellulose ester film (F).

Here, the film width-retaining zone A in the tenter 4 is a zone in which the distance between the gripping clips of the film width (both ends of the base) from the entrance of the tenter 4 to the starting point a is constant. The stretching zone B is a zone in which the distance between the gripping clips of the film width (both ends of the base) from the stretching start point a to the stretching end point b of the tenter 4 is extended in the advancing direction . The film width maintaining zone C in the stretched state refers to a zone in which the distance between the gripping clips of the film width (both ends of the base) after stretching from the stretching end point b of the tenter 4 to the releasing point c of the gripping clip 4 is constant It says. In the latter half of the film width maintaining zone C, it is also preferable to provide a relaxation treatment when the stress in the width direction of the stretched film F is excessively strong.

The rail 12 in the tenter 4 is generally a bendable rail and the rail 12 is bent so that the distance between the left and right ends of the rail 12 is changed. The width maintaining zone C can be formed. The stretching zone (B) corresponds to the stretching step of the present invention. Also, the combination of these zones is not limited to the one illustrated, and may be combined in any order.

The tenter 4 shown in the drawing is a clip tenter system, but this may be a pin tenter system. In addition, since the drying while maintaining the width of the stretched cellulose ester film (F) in a tenter system improves the planarity and dimensional stability desirable.

In order to widen the stretched cellulose ester film of the present invention, it is preferable that the unstretched cellulose ester film (Fo) is stretched in the film width direction at a stretching magnification in the range of 25 to 100%, and from the viewpoint of improving productivity and avoiding breakage It is more preferable that the draw ratio is in the range of 30 to 50%.

The stretched cellulose ester film of the present invention is characterized in that a part of the sectional shape in the width direction of the A side is represented by a hanging curve. Even if the stretching process is performed by the set stretching magnification, As shown, a part of the cross-sectional shape of the non-stretch-treated film with respect to the width direction of the side A is also flexible as shown by the hanging curve.

The stretching operation may be performed not only in the width direction (TD direction) of the film but also in the longitudinal direction (MD direction) of the film. For example, a peripheral speed difference is applied to a plurality of rollers, A method in which both ends of the web are fixed with clips or pins and the distance between the clips and the pin is extended in the advancing direction and the stretching is performed in the MD direction; And a method of stretching in the direction of the film.

The film transporting tension in the film forming process in a tenter or the like is preferably in the range of 120 to 200 N / m, more preferably in the range of 140 to 200 N / m, depending on the temperature. And most preferably in the range of 140 to 160 N / m.

The stretching temperature is preferably in the range of (Tg-30) to (Tg + 100) ° C, more preferably in the range of (Tg-20) to (Tg +80) DEG C, more preferably within the range of (Tg-5) to (Tg + 20) DEG C. The Tg of the film can be determined by the method described in JIS K7121. The specific stretching treatment temperature is preferably in the range of 160 to 190 캜. It is preferable that the entire tenter 4 is provided in the housing and hot air is supplied into the housing from the hot air supply device (not shown) so that the temperature becomes constant.

The stretching time is appropriately selected, but it is preferable that the stretching time is relatively short in view of the planarity and the dimensional stability. Specifically, it is preferably in the range of 1 to 10 seconds, more preferably 4 to 10 seconds. Further, the stretching speed in the width direction may be constant or may be changed. The stretching speed is preferably in the range of 50 to 500% / min, more preferably in the range of 100 to 400% / min, and most preferably in the range of 200 to 300% / min.

4 is a schematic view of the stretched cellulose ester film of the present invention.

The unstretched cellulose ester film (Fo) is transported to a tenter, and an end portion thereof is gripped with a clip or the like, and is stretched at a predetermined stretch magnification.

The elongated cellulose ester film (F) of the present invention has an arithmetic mean roughness (Ra) at the end portion and an arithmetic average roughness at the center portion of the stretched cellulose ester film (F) ) Is in the range of 2.2 to 3.5 nm and is higher in the range of 0.3 to 1.0 nm than the average value of the arithmetic average roughness (Ra) of the end portion of the film A surface in order to reduce the fluctuation on the roller in the high- From the viewpoint of further suppressing the notch failure.

Here, the end refers to the end Ho to L x 0.05 of the stretched cellulose ester film when the total width of the stretched cellulose ester film is L, and in Fig. 4, it refers to the area (H). The central portion refers to a portion of ± L × 0.1 in the width direction from the central portion (L / 2) of the film when the entire width of the stretched cellulose ester film is represented by L, and in FIG. 4, it refers to the area (T).

The average value of the arithmetic average roughness Ra of the end portion is obtained by selecting ten points in the longitudinal direction with respect to the end portion (the area H) and measuring the arithmetic average roughness Ra and obtaining the average value thereof.

The average value of the arithmetic average roughness Ra of the center portion is obtained by selecting ten points in the longitudinal direction with respect to the central portion (the area T) and measuring the arithmetic mean roughness Ra and obtaining the average value thereof.

The arithmetic average roughness (Ra) is a value specified in JIS B 0601, and examples of the measuring method include a touch method or an optical method.

The arithmetic mean roughness (Ra) according to the present invention can be measured using a noncontact surface fine shape measuring device WYKO NT-2000.

5 is a schematic diagram showing a preferred stretching treatment method in the present invention.

As a preferred method for producing the stretched cellulose ester film of the present invention, the surface temperature of the A-plane end portion of the unstretched cellulose ester film (Fo) is preferably 10 to 50 占 폚 And the stretching treatment is carried out at a low level in the range. However, the present invention is not limited to this method. Here, the A side of the unstretched cellulose ester film (Fo) refers to a side opposite to the belt side or the side contacting the drum side when the film is flexible on the belt or drum to form the film dope.

Here, the end portion refers to the end portion or Lo × 0.05 portion of the film when the total width of the unstretched cellulose ester film (Fo) is Lo, and the central portion refers to the total width of the unstretched cellulose ester film (Fo) Lo, &quot; refers to a portion of 占 L 占 0.1 in the width direction from the center portion of the film.

The film surface temperature at the end portion and the center portion can be measured using a contact type handy thermometer (ANRITSU DIGITAL THERMOMETER HA-100K). Concretely, five points are respectively measured with respect to the width direction at the point (a) at which the stretching process of the film being transported is started, and the average value can be set as the film temperature of the portion.

By changing the temperature during the stretching process at the end and the center, the arithmetic mean roughness (Ra) can be controlled to the above-mentioned numerical range. The mechanism has not yet departed from the estimation region. However, since the center portion of the cellulose ester resin is softened and the method of arranging the polymer chains of the cellulose ester resin is changed by changing the temperature during the stretching treatment to the central portion at a high temperature, It is considered that the matte is liable to be unevenly distributed, and the arithmetic mean roughness Ra varies.

The method of adjusting the temperature is preferably a method of locally spraying cold air to the end portion. At least one pair of cold air generating portions G1 are provided, and from the cold air generating portion at the end, It is preferable to conduct the stretching treatment while appropriately blowing a cold air to the end portion of the unstretched cellulose ester film (Fo) so as to be a low temperature within the range of 10 to 50 ° C.

It is preferable that the end cold air generating portion injects the cold air whose temperature is controlled by a cold air generating device (not shown) to the entire end portion of the unstretched cellulose ester film (Fo) from the nozzle-like air outlet, The distance to the end of the film, and the like can be appropriately selected, but it is preferable to positionally cover at least the front and rear of the point (a) at which the stretching treatment of the unstretched cellulose ester film (Fo) is started. Further, when the entire width of the unstretched cellulose ester film (Fo) is defined as Lo as an area for spraying the cold wind, it is possible to effectively adjust the temperature at the end portion and the central portion .

In the stretching step, the temperature distribution in the width direction of the atmosphere is preferably small from the viewpoint of enhancing the uniformity of the film, and the temperature distribution in the width direction at the end portion and the central portion is preferably within ± 5 ° C, More preferably, within ± 1 ° C.

In Fig. 5, a pair of cold-air generating zones G1 are provided in the vicinity of the starting point (a) of the stretching treatment so as to cover both ends of the unstretched cellulose ester film Fo. The position of the end cold air generating portion G1 in Fig. 5 indicates a preferable position, but is not limited thereto.

Further, it is also preferable to provide the end cold wind generating portion G2 after the stretching end point (b). By setting the cold wind temperature to be between the middle portion temperature and the end portion temperature of the stretched cellulose ester film, have.

Hereinafter, materials used in the present invention will be described.

<Cellulose Ester>

The cellulose ester used in the stretched cellulose ester film of the present invention has an average acetyl group substitution degree in the range of 2.8 to 2.95 as a whole of the cellulose ester. The average degree of acetyl group substitution is more preferably in the range of 2.85 to 2.95. The acetyl group substitution degree of the cellulose ester can be measured according to ASTM-D817-96.

The cellulose ester used in the present invention is not particularly limited as long as it satisfies the acetyl group degree of substitution. The cellulose ester is a carboxylic acid ester having about 2 to 22 carbon atoms and may be an ester of an aromatic carboxylic acid. In particular, Ester is preferred. A lower fatty acid in a lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms. The acyl group bonded to the hydroxy group may be linear, branched or may form a ring. Other substituents may be substituted. In the case of the same degree of substitution, since the birefringence is lowered when the number of carbon atoms is larger, the number of carbon atoms is preferably selected from an acyl group having 2 to 6 carbon atoms. The cellulose ester preferably has 2 to 4 carbon atoms, more preferably 2 to 3 carbon atoms.

The cellulose ester may be an acyl group derived from a mixed acid, particularly preferably an acyl group having 2 or 3 carbon atoms or 2 or 4 carbon atoms. In the present invention, a mixed fatty acid ester of cellulose having a propionate group or a butyrate group bonded to an acetyl group such as cellulose acetate propionate, cellulose acetate butyrate, or cellulose acetate propionate butyrate may be used as the cellulose ester. The butyryl group forming the butyrate may be linear or branched.

The cellulose ester particularly preferably used in the present invention is triacetyl cellulose having an average acetyl group degree of substitution in the range of 2.8 to 2.95.

When the degree of substitution of the acetyl group is within the above range, the unreacted portion of the hydroxy group of the pyranose ring constituting the skeleton of the cellulose resin is small and the residual hydroxyl group is decreased, thereby causing dimensional changes and warping, Occurrence of slit failure at the time is not shown and the physical properties as a binder are high.

When the substitution degree of the average acetyl group is within the above range, orientation disturbance of the cellulose when stretched at a high magnification is small, and the effect of suppressing the fluctuation of the retardation is high.

The weight average molecular weight (Mw) of the cellulose ester according to the present invention is preferably 75000 or more, and more preferably 75000 to 300000.

When the weight average molecular weight (Mw) of the cellulose ester resin is in the range of 75000 to 300000, excellent heat resistance and brittleness are obtained, and the viscosity range is suitable, so that film formation is easy.

The weight average molecular weight (Mw) of the cellulose ester can be measured as follows.

It is measured by high performance liquid chromatography under the following conditions.

Solvent: methylene chloride

Column: Shodex K806, K805, K803G (connected by using three connections manufactured by Showa Denko K.K.)

Column temperature: 25 ° C

Sample concentration: 0.1 mass%

Detector: RI Model 504 (manufactured by GL Science)

Pump: L6000 (manufactured by Hitachi Seisakusho Co., Ltd.)

Flow rate: 1.0 ml / min

Calibration curve: standard polystyrene STK standard Polystyrene (manufactured by TOSOH CORPORATION) Using a calibration curve of 13 samples with Mw = 1000000 to 500, 13 samples are preferably used at almost regular intervals

The cellulose used as the raw material of the cellulose ester used in the present invention is not particularly limited, but wood pulp (softwood pulp, hardwood pulp) and cotton linter can be used. The Mw of the cellulose ester can be controlled by using a kind of cellulose or a plurality of raw material cellulose. For example, when the hardwood hydrolysis kraft pulp is used for esterification, the Mw of the cellulose ester increases, and when the softwood sulphite pulp is used, the Mw tends to be small. Therefore, the cellulose may be used singly or in combination of two or more kinds. For example, softwood pulp, cotton linter or hardwood pulp may be used in combination. As the cellulose, pulp (especially softwood pulp) is often used. The content (% by mass) of the? -Cellulose in cellulose may be generally from 94 to 99 (for example, from 95 to 99), preferably from 96 to 98.5 (for example, from 97.3 to 98).

When the acylating agent as the cellulose raw material according to the present invention is an acid anhydride (acetic anhydride, propionic anhydride, butyric anhydride), an organic acid such as acetic acid or an organic solvent such as methylene chloride is used and a proton The reaction is carried out using a catalyst. When the acylating agent is an acid chloride (CH ₃ COCl, C ₂ H ₅ COCl, or C ₃ H ₇ COCl), the reaction is carried out using a basic compound such as amine as a catalyst. Specifically, it can be synthesized by referring to the method described in JP-A-10-45804.

In addition, the cellulose ester is also affected by trace metal components in the cellulose ester. These are considered to be related to the water used in the manufacturing process. It is preferable that the amount of the component which can be insoluble nuclei is small, and the metal ion such as iron, calcium, and magnesium may contain an organic acidic group It is preferable to form an insoluble matter by forming a salt with a polymer degradation product or the like. And it is preferably 1 ppm or less with respect to the iron (Fe) component. For the calcium (Ca) component, an acidic component such as a carboxylic acid or a sulfonic acid, and a scum (insoluble sediments, turbidity) derived from most insoluble calcium are easy to form with a coordination compound, .

The content of the calcium (Ca) component is 60 ppm or less, preferably 0 to 30 ppm. With respect to the magnesium (Mg) component, too large an amount of undissolved components is preferably generated in the range of 0 to 70 ppm, more preferably 0 to 20 ppm. The metal components such as iron (Fe) content, calcium (Ca) content and magnesium (Mg) content can be obtained by pretreating the completely dried cellulose ester with a micro digest wet cracking apparatus (sulfuric acid decomposition) Can be analyzed using an ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometer).

(Plasticizer)

The stretched cellulose ester film of the present invention preferably contains a suitable amount of a plasticizer in the absence of stretching at the time of stretching and, if necessary, from the viewpoint of obtaining the effect of the present invention. The plasticizer is not particularly limited, but is preferably selected from a polyhydric alcohol ester plasticizer, a polycarboxylic acid ester plasticizer, a glycolate plasticizer, a phthalate ester plasticizer, a fatty acid ester plasticizer, a polyester plasticizer and an acrylic plasticizer .

The polyhydric alcohol ester is preferably composed of an ester of a divalent or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and has an aromatic ring or a cycloalkyl ring in the molecule.

The polyhydric alcohol used is represented by the following formula (1).

R1- (OH)_n (1)

(Wherein R &lt; 1 &gt; is an organic group of n, and n represents a positive integer of 2 or more)

Examples of preferred polyhydric alcohols include, for example, the following, but the present invention is not limited thereto. Propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,2-butanediol, 1,2-butanediol, 1,3-propanediol, 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, trimethylol propane, trimethylol ethane, xylitol, pentaerythritol, dipentaerythritol and the like. Among them, trimethylolpropane and pentaerythritol are preferable.

The monocarboxylic acid used in the polyhydric alcohol ester is not particularly limited and known aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, and aromatic monocarboxylic acids can be used. The use of an alicyclic monocarboxylic acid or an aromatic monocarboxylic acid is preferable in terms of improving moisture permeability and retention. Examples of preferred monocarboxylic acids include, but are not limited to, the following.

As the aliphatic monocarboxylic acid, a linear or branched chain fatty acid having 1 to 32 carbon atoms can be preferably used. More preferably from 1 to 20 carbon atoms, and particularly preferably from 1 to 10 carbon atoms. Use of acetic acid increases the compatibility with the cellulose ester, so that it is preferable to use acetic acid and other monocarboxylic acids in combination.

Preferred aliphatic monocarboxylic acids are acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2- ethylhexanecarboxylic acid, undecylic acid, But are not limited to, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, myristic acid, pentadecylic acid, palmitic acid, Unsaturated fatty acids such as maleic acid, maleic acid and lactic acid, and unsaturated fatty acids such as undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid. Examples of preferred alicyclic monocarboxylic acids include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, and derivatives thereof. Examples of preferred aromatic monocarboxylic acids include those obtained by introducing an alkyl group into a benzene ring of a benzoic acid such as benzoic acid or toluic acid, a benzene ring containing two or more benzene rings such as biphenylcarboxylic acid, naphthalenecarboxylic acid and tetralinecarboxylic acid Or an aromatic monocarboxylic acid, and derivatives thereof. In particular, benzoic acid is preferred.

The molecular weight of the polyhydric alcohol ester is preferably in the range of 300 to 1500, more preferably in the range of 350 to 750. A larger molecular weight is preferable because it is less likely to volatilize, and a smaller molecular weight is preferable from the viewpoint of moisture permeability and compatibility with a cellulose ester. The carboxylic acid used in the polyhydric alcohol ester may be one type, or may be a mixture of two or more types. The OH group in the polyhydric alcohol may be all esterified, or a part thereof may be left as an OH group. Specific compounds of polyhydric alcohol esters are shown below.

Trimethylolpropane triacetate, pentaerythritol tetraacetate and the like are also preferably used.

The glycolate-based plasticizer is not particularly limited, but alkyl phthalyl alkyl glycolates can be preferably used. The alkyl phthalyl alkyl glycolates include, for example, methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octylphthalyl octyl glycolate, Ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl Glycolate, butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octylphthalyl methyl glycolate, and octylphthalyl ethyl glycolate.

Examples of the phthalate ester plasticizers include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, dicyclohexyl terephthalate, .

Examples of the citrate ester plasticizer include acetyltrimethyl citrate, acetyltriethyl citrate, and acetyl tributyl citrate.

Examples of the fatty acid ester plasticizers include butyl oleate, methyl acetyl ricinolate, and dibutyl sebacate.

Examples of the phosphate ester plasticizer include triphenyl phosphate, tricresyl phosphate, cresyldiphenyl phosphate, octyldiphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate and the like.

The polycarboxylic acid ester compound is composed of an ester of a polyhydric carboxylic acid and an alcohol having a valence of 2 or more, preferably 2 to 20, The aliphatic polycarboxylic acid is preferably 2 to 20 carbon atoms, and in the case of an aromatic polycarboxylic acid and an alicyclic polycarboxylic acid, it is preferably 3 to 20 carbon atoms.

The polycarboxylic acid is represented by the following formula (2).

R2 (COOH)_m(OH)_n (2)

(Wherein m is an integer of 2 or more, n is an integer of 0 or more, a COOH group is a carboxyl group, and an OH group is an alcoholic or phenolic hydroxy group)

Examples of preferred polyvalent carboxylic acids include, but are not limited to, the following. Aromatic polycarboxylic acids or derivatives thereof having three or more valences such as trimellitic acid, trimesic acid and pyromellitic acid, aliphatic polycarboxylic acids or derivatives thereof such as succinic acid, adipic acid, azelaic acid, sebacic acid, oxalic acid, fumaric acid, maleic acid and tetrahydrophthalic acid Oxycarboxylic acids such as polycarboxylic acids, tartaric acid, tartronic acid, malic acid and citric acid may be preferably used. Particularly, it is preferable to use oxydacarboxylic acid in view of improvement in retention property and the like.

As the alcohol used in the polyvalent carboxylic acid ester compound usable in the present invention, known alcohols and phenols can be used without particular limitation. For example, aliphatic saturated alcohols or aliphatic unsaturated alcohols having 1 to 32 carbon atoms may be preferably used. More preferably from 1 to 20 carbon atoms, and particularly preferably from 1 to 10 carbon atoms. In addition, alicyclic alcohols such as cyclopentanol and cyclohexanol or derivatives thereof, aromatic alcohols such as benzyl alcohol and cinnamyl alcohol, and derivatives thereof may also be preferably used.

When an oxydarboxylic acid is used as the polycarboxylic acid, the alcoholic or phenolic hydroxy group of the oxydarboxylic acid may be esterified using a monocarboxylic acid. Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.

As the aliphatic monocarboxylic acid, a linear or branched chain fatty acid having 1 to 32 carbon atoms can be preferably used. More preferably from 1 to 20 carbon atoms, and particularly preferably from 1 to 10 carbon atoms.

Preferred aliphatic monocarboxylic acids are acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2- ethylhexanecarboxylic acid, undecylic acid, But are not limited to, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, tridecanoic acid, myristic acid, pentadecylic acid, palmitic acid, Unsaturated fatty acids such as maleic acid, maleic acid and lactic acid, and unsaturated fatty acids such as undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid.

Examples of preferred alicyclic monocarboxylic acids include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, and derivatives thereof.

Examples of preferred aromatic monocarboxylic acids include those obtained by introducing an alkyl group into a benzene ring of a benzoic acid such as benzoic acid or toluic acid, a benzene ring containing two or more benzene rings such as biphenylcarboxylic acid, naphthalenecarboxylic acid and tetralinecarboxylic acid Or an aromatic monocarboxylic acid, and derivatives thereof. Particularly preferred are acetic acid, propionic acid and benzoic acid.

Although the molecular weight of the polycarboxylic acid ester compound is not particularly limited, it is preferably in the range of 300 to 1000, more preferably in the range of 350 to 750. In view of improving the retention property, the larger one is preferable, and the smaller the water permeability and the compatibility with the cellulose ester, the smaller is preferable.

The alcohols used in the polycarboxylic acid ester may be one kind or two or more kinds.

The acid value of the polycarboxylic acid ester compound is preferably 1 mgKOH / g or less, more preferably 0.2 mgKOH / g or less. By setting the acid value in the above range, fluctuation of the environment of retardation is suppressed, which is preferable.

(Acid value)

Refers to the number of milligrams of potassium hydroxide needed to neutralize the acid (the carboxyl group present in the sample) contained in 1 g of acid. The acid value is measured in accordance with JIS K0070.

Examples of particularly preferable polyvalent carboxylic acid ester compounds are shown below, but the present invention is not limited thereto. For example, there may be mentioned triethyl citrate, tributyl citrate, acetyl triethyl citrate (ATEC), acetyl tributyl citrate (ATBC), benzoyl tributyl citrate, acetyltriphenyl citrate, acetyl tribenzyl citrate, Dibutyl tartarate, diacetyl dibutyl tartrate, tributyl trimellitate, tetrabutyl pyromellitate, and the like.

(Ester ester compound)

The stretched cellulose ester film of the present invention is characterized in that it contains a sugar ester compound represented by the following formula (3) (in the present invention, a sugar ester compound other than a cellulose ester is referred to as a sugar ester compound) And is preferable in terms of promoting uniform phase difference expression.

(Wherein R ₁ to R ₈ represent a hydrogen atom, a substituted or unsubstituted alkylcarbonyl group having 2 to 22 carbon atoms, or a substituted or unsubstituted arylcarbonyl group having 2 to 22 carbon atoms, and R ₁ to R ₈ may be the same Lt; / RTI &gt;

The average substitution degree of the compound represented by the formula (3) used in the present invention is 3.0 to 6.5, which is effective in suppressing an increase in haze in the stretching treatment and exhibiting a uniform phase difference. The average degree of substitution is more preferably in the range of 4.5 to 6.5.

In the present invention, the substitution degree of the compound represented by the formula (3) represents the number of substituents other than hydrogen among the eight hydroxyl groups contained in the formula (3), that is, R ₁ to R 3 in the formula (3) R &lt; ₈ &gt; represents a group containing a group other than hydrogen. Therefore, when all of R ₁ to R ₈ are substituted by substituents other than hydrogen, the degree of substitution is a maximum value of 8.0, and when R ₁ to R ₈ are both hydrogen atoms, the degree of substitution is 0.0.

It is known that it is difficult to synthesize a single kind of compound in which the number of hydroxyl groups and the number of OR groups are fixed, and the compound represented by the formula (3) is a compound in which several kinds of components having different numbers of hydroxyl groups and OR groups are mixed Therefore, it is appropriate to use an average degree of substitution as the substitution degree of the formula (3) in the present invention, and the average degree of substitution can be measured from the area ratio of the chart showing the degree of substitution degree by high performance liquid chromatography .

Examples of the sugar of the synthesis material of the sugar ester compound used in the present invention include the following, but the present invention is not limited thereto.

The present invention also relates to a method for producing a compound of formula (I) or a salt thereof, wherein the compound is selected from the group consisting of glucose, galactose, mannose, fructose, xylose, arabinose, lactose, sucrose, Maltose, celotriose, maltotriose, raffinose or kestose.

Other examples include gentiobiose, gentiootriose, gentiootetraose, xylotriose, and galactosyl sucrose.

The monocarboxylic acid used in the synthesis of the sugar ester compound used in the present invention is not particularly limited and known aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, and aromatic monocarboxylic acids can be used. One carboxylic acid may be used, or two or more carboxylic acids may be used.

Examples of preferred aliphatic monocarboxylic acids are acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enantic acid, caprylic acid, pelargonic acid, capric acid, 2- ethylhexanecarboxylic acid, But are not limited to, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachic acid, behenic acid, lignoceric acid, Unsaturated fatty acids such as montanic acid, melissic acid and lactic acid, and unsaturated fatty acids such as undecylenic acid, oleic acid, sorbic acid, linolic acid, linolenic acid, arachidonic acid and octetic acid.

Examples of preferred alicyclic monocarboxylic acids include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, and derivatives thereof.

Examples of preferred aromatic monocarboxylic acids include aromatic monocarboxylic acids, benzoic acid, biphenylcarboxylic acid, naphthalenecarboxylic acid, benzenecarboxylic acid, benzenecarboxylic acid, and naphthalenecarboxylic acid in which 1 to 5 alkyl or alkoxy groups are introduced into a benzene ring of benzoic acid such as benzoic acid and toluic acid. An aromatic monocarboxylic acid having two or more benzene rings such as tetracarboxylic acid, tetracarboxylic acid and the like, or derivatives thereof, and benzoic acid is particularly preferable.

Particular examples of the sugar ester compound represented by the formula (3) are shown below, but they are all cases where R ₁ to R ₈ are all the same substituent R, and the present invention is not limited thereto. In the following table, when the average degree of substitution is less than 8.0, any one of R ₁ to R ₈ represents a hydrogen atom.

The sugar ester compound used in the present invention can be produced by reacting a sugar with an acylating agent (also referred to as an esterifying agent, for example, an acid halide of acetyl chloride, an anhydride such as acetic anhydride) The amount of the acylating agent, the timing of addition, and the esterification reaction time. However, by mixing a compound having a degree of substitution of a sugar ester compound having a degree of substitution or a compound having a degree of substitution purely isolated, The following components in Fig. 4 can be adjusted.

(Synthesis Example: Synthesis of Compound According to the Present Invention)

34.2 g (0.1 mol) of sucrose, 135.6 g (0.6 mol) of anhydrous benzoic acid and 284.8 g (3.6 mol) of pyridine were fed into a four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen gas introducing tube, The temperature was raised while bubbling nitrogen gas through the gas introduction pipe, and the esterification reaction was carried out at 70 ° C for 5 hours.

Subsequently, the inside of the flask was depressurized to 4 × 10 ² Pa or less, excess pyridine was distilled off at 60 ° C., the pressure in the flask was reduced to 1.3 × 10 5 Pa or less, and the temperature was raised to 120 ° C. to remove anhydrous benzoic acid. And distilled off. Subsequently, 300 g of an aqueous solution of sodium carbonate of 0.5% by mass in 1 L of toluene was added, stirred at 50 캜 for 30 minutes, and then allowed to stand to separate the toluene layer. Finally, 100 g of water was added to the separated toluene layer, and the mixture was washed with water at room temperature for 30 minutes. Then, the toluene layer was collected and toluene was distilled off at 60 캜 under reduced pressure (4 × 10 ² Pa or less) , A-2, A-3, A-4 and A-5.

The obtained mixture was analyzed by high performance liquid chromatography-mass spectrometry (HPLC-MS) to find that the content of A-1 was 1.2% by mass, that of A-2 was 13.2% by mass, that of A-3 was 14.2% %, A-5 and the like were 40.0% by mass. The average degree of substitution was 5.2.

Similarly, 158.2 g (0.7 mole), 146.9 g (0.65 mole), 135.6 g (0.6 mole), and 124.3 g (0.55 mole) of anhydrous benzoic acid were reacted with pyridine having a sugar moiety .

Subsequently, a part of the obtained mixture was purified by column chromatography using silica gel to obtain A-1, A-2, A-3, A-4 and A-5 with a purity of 100%.

In addition, A-5 and the like mean a mixture of all components having a degree of substitution of 4 or less, that is, a compound of substitution degree 4, 3, 2 or 1. The average degree of substitution was calculated as A-5, etc. as the degree of substitution 4.

In the present invention, average degree of substitution was adjusted by adding the sugar ester and the isolated A-1 to A-5 or the like which are close to the desired degree of substitution desired by the method described herein.

&Lt; Measurement conditions of HPLC-MS >

1) LC section

(JASCO CO-965), a detector (JASCO UV-970-240nm), a pump (JASCO PU-980) and a deaerator (JASCO DG-980-50) manufactured by Nippon Bunko Co.,

Column: Inertsil ODS-3 Particle diameter 5 占 퐉 4.6 占 250 mm (manufactured by GL Science Co., Ltd.)

Column temperature: 40 DEG C

Flow rate: 1 ml / min

Mobile phase: THF (1% acetic acid): H ₂ O (50:50)

Injection amount: 3 μl

2) MS Department

Apparatus: LCQ DECA (manufactured by Thermo Quest Co., Ltd.)

Ionization method: Electrospray ionization (ESI) method

Spray voltage: 5kV

Capillary temperature: 180 ° C

Vaporizer temperature: 450 DEG C

The stretched cellulose ester film of the present invention preferably contains the sugar ester compound in an amount of 1 to 20 mass%, particularly 3 to 15 mass%. Within this range, excellent effects of the present invention, namely stabilization of retardation, are exhibited, and bleeding-out during storage of the raw material is not required.

(Polyester compound)

The stretched cellulose ester film of the present invention preferably contains a polyester-based compound represented by the following formula (4) in view of preventing haze by stretching and suppressing breakage or the like.

The polyester-based compound is preferably a polyester-based compound having an aromatic ring or a cycloalkyl ring in the molecule. As the polyester compound, it is preferable to use an aromatic terminal ester plasticizer which can be represented by the following chemical formula (4).

B- (GA) _n- GB &lt; _RTI ID = 0.0 &gt;

(Wherein B is a benzene monocarboxylic acid residue, G is an alkylene glycol residue having 2 to 12 carbon atoms or an aryl glycol residue having 6 to 12 carbon atoms or an oxyalkylene glycol residue having 4 to 12 carbon atoms, A is an alkylene glycol residue having 4 to 12 carbon atoms Or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more)

In the formula (4), an alkylene glycol residue or an oxyalkylene glycol residue or an aryl glycol residue represented by G, a benzene monocarboxylic acid residue represented by B, an alkylenedicarboxylic acid residue represented by A, And is obtained by a reaction similar to that of a conventional polyester-based plasticizer.

Examples of the benzene monocarboxylic acid component of the polyester plasticizer include benzoic acid, para-tert-butylbenzoic acid, orthotoluenic acid, meta-toluic acid, paratoluic acid, dimethylbenzoic acid, ethylbenzoic acid, Acetoxybenzoic acid, and the like, and these may be used individually or as a mixture of two or more kinds.

Examples of the alkylene glycol component having 2 to 12 carbon atoms in the polyester plasticizer include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, Methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2- 1,3-propanediol (3,3-dimethylol pentane), 2-n-butyl-2-ethyl- Pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, -Nonanediol, 1,10-decanediol, 1,12-octadecanediol, and the like, and these glycols are used as one kind or as a mixture of two or more kinds. Particularly, the alkylene glycol having 2 to 12 carbon atoms is particularly preferable because of its excellent compatibility with the cellulose ester.

Examples of the oxyalkylene glycol component having 4 to 12 carbon atoms in the aromatic terminal ester include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol. These glycols include one kind Or a mixture of two or more thereof.

Examples of the alkylene dicarboxylic acid component having 4 to 12 carbon atoms in the aromatic terminal ester include succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid and dodecanedicarboxylic acid. These may be used individually or as a mixture of two or more. Examples of the arylene dicarboxylic acid component having 6 to 12 carbon atoms include phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalene dicarboxylic acid, and 1,4-naphthalene dicarboxylic acid.

The number average molecular weight of the polyester plasticizer is preferably in the range of 300 to 1500, more preferably in the range of 400 to 1000. The acid value is not more than 0.5 mg KOH / g, the hydroxyl value is not more than 25 mg KOH / g, more preferably the acid value is not more than 0.3 mg KOH / g, and the hydroxyl value is not more than 15 mg KOH / g.

Hereinafter, synthesis examples of an aromatic terminal ester plasticizer are shown.

&Lt; Sample No.1 (aromatic terminal ester sample) >

410 parts of phthalic acid, 610 parts of benzoic acid, 737 parts of dipropylene glycol and 0.40 part of tetraisopropyl titanate as a catalyst were fed into a reaction vessel, and a reflux condenser was attached in a nitrogen stream while stirring to reflux the excess monohydric alcohol. The heating was continued in the range of 130 to 250 캜 until the temperature became 2 or less to continuously remove the generated water. Subsequently, the effluent was removed under a reduced pressure of 1.33 × 10 ⁴ Pa to finally 4 × 10 ² Pa or less within the range of 200 to 230 ° C., and then filtered to obtain an aromatic terminal ester plasticizer having the following characteristics.

Viscosity (25 占 폚, mPa 占 퐏); 43400

Acid value; 0.2

&Lt; Sample No. 2 (aromatic terminal ester sample) >

An aromatic terminal ester having the following characteristics was obtained in the same manner as in Sample No. 1, except that 410 parts of phthalic acid, 610 parts of benzoic acid, 341 parts of ethylene glycol and 0.35 part of tetraisopropyl titanate as a catalyst were used in the reaction vessel.

Viscosity (25 占 폚, mPa 占 퐏); 31000

Acid value; 0.1

&Lt; Sample No. 3 (aromatic terminal ester sample) >

The same procedure as in Sample No. 1 was repeated except that 410 parts of phthalic acid, 610 parts of benzoic acid, 418 parts of 1,2-propanediol, and 0.35 part of tetraisopropyl titanate were used as a catalyst, and the aromatic terminal ester .

Viscosity (25 占 폚, mPa 占 퐏); 38000

Acid value; 0.05

&Lt; Sample No. 4 (aromatic terminal ester sample) >

The reaction was carried out in the same manner as in Sample No. 1 except that 410 parts of phthalic acid, 610 parts of benzoic acid, 418 parts of 1,3-propanediol and 0.35 parts of tetraisopropyl titanate were used as the catalyst, and the aromatic terminal ester .

Viscosity (25 占 폚, mPa 占 퐏); 37000

Acid value; 0.05

Specific compounds of the aromatic terminal ester plasticizer are shown below, but the present invention is not limited thereto.

In the stretched cellulose ester film of the present invention, it is preferable that the polyester-based compound is contained in the stretched cellulose ester film in the range of 1 to 20 mass%, particularly 3 to 11 mass%. Within this range, the excellent effect of the present invention can be exhibited and failure such as breakage can be suppressed.

(Ultraviolet absorber)

The stretched cellulose ester film of the present invention may contain an ultraviolet absorber. The ultraviolet absorber is intended to improve durability by absorbing ultraviolet rays of 400 nm or less, and particularly preferably has a transmittance at a wavelength of 370 nm of 10% or less, more preferably 5% or less, further preferably 2% to be.

The ultraviolet absorber to be used in the present invention is not particularly limited, and examples thereof include oxybenzophenone compounds, benzotriazole compounds, salicylic ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, Based compounds, inorganic powders, and the like.

Benzotriazole, (2-2H-benzotriazol-2-yl) -6- (3,5-di-sec- (Straight chain and branched dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2,4-benzyloxybenzophenone and the like, and also Tinuvin 109, Tinuvin 171, Tinuvin 234, Tinuvin 326, Tinuvin 327 and Tinuvin 328, all of which are commercially available from BASF Japan and can be preferably used.

The ultraviolet absorber preferably used in the present invention is a benzotriazole ultraviolet absorber, a benzophenone ultraviolet absorber, a triazine ultraviolet absorber, and particularly preferably a benzotriazole ultraviolet absorber or a benzophenone ultraviolet absorber.

Specific examples of the benzotriazole-based ultraviolet absorber used in the present invention are illustrated below, but the present invention is not limited thereto.

UV-1: 2- (2'-hydroxy-5'-methylphenyl) benzotriazole

UV-2: 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole

UV-3: 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole

UV-4: 2- (2'-hydroxy-3 ', 5'-di-tert- butylphenyl) -5-chlorobenzotriazole

UV-5: 2- (2 ' -hydroxy-3 '-( 3 &quot;, 4 &quot;, 5 &quot;, 6 &quot; -tetrahydrophthalimidomethyl) -5 ' -methylphenyl) benzotriazole

UV-6: 2,2-methylene bis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-

UV-7: 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole

UV-8: 2- (2H-benzotriazol-2-yl) -6- (straight and branched dodecyl) -4-methylphenol (Tinuvin 171)

UV-9: octyl-3- [3- tert -butyl-4-hydroxy-5- (chloro-2H-benzotriazol- 2-yl) phenyl] propionate and 2-ethylhexyl- (tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate

Specific examples of the benzophenone ultraviolet absorber are shown below, but the present invention is not limited thereto.

UV-10: 2,4-dihydroxybenzophenone

UV-11: 2,2'-dihydroxy-4-methoxybenzophenone

UV-12: 2-hydroxy-4-methoxy-5-sulfobenzophenone

UV-13: bis (2-methoxy-4-hydroxy-5-benzoylphenylmethane)

In addition, a discotic compound such as a compound having 1,3,5-triazine ring is also preferably used as an ultraviolet absorber.

The stretched cellulose ester film of the present invention preferably contains two or more ultraviolet absorbers.

As the ultraviolet absorber, a polymer ultraviolet absorber can be preferably used. In particular, a polymer-type ultraviolet absorber described in JP-A-6-148430 is preferably used.

The ultraviolet absorber may be added by dissolving an ultraviolet absorber in an alcohol such as methanol, ethanol, butanol, or an organic solvent such as methylene chloride, methyl acetate, acetone, or dioxolane, or a mixed solvent thereof, . The organic solvent and cellulose ester which are not dissolved in an organic solvent such as an inorganic powder are dispersed using a dissolver or a sand mill and then added to the dope.

The amount of the ultraviolet absorber to be used is not uniform depending on the kind of the ultraviolet absorber and the conditions of use, but when the dried film thickness of the stretched cellulose ester film is within the range of 30 to 200 탆, the stretched cellulose ester film is preferably used in a range of 0.5 to 10% By mass, more preferably in the range of 0.6 to 4% by mass.

(Fine particles)

The stretched cellulose ester film of the present invention is preferably a film containing fine particles from the viewpoint of improving the slipperiness by adjusting the arithmetic mean roughness (Ra) and eliminating defective conveying such as pulling.

Examples of the fine particles include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate . The fine particles include silicon, which is preferable in that turbidity is low, and silicon dioxide is particularly preferable.

The average particle diameter of the primary particles of the fine particles is preferably in the range of 5 to 400 nm, more preferably in the range of 10 to 300 nm. These particles may be mainly contained as secondary aggregates having a particle diameter in the range of 0.05 to 0.3 탆, and may be contained as primary particles without aggregation if the particles have an average particle diameter within the range of 100 to 400 nm. The content of these fine particles in the stretched cellulose ester film is preferably in the range of 0.01 to 1 mass%, particularly preferably in the range of 0.05 to 0.5 mass%. In the case of a multi-layered stretched cellulose ester film obtained by a covalent bonding method, it is preferable to contain the added amount of fine particles on the surface.

The fine particles of silicon dioxide are commercially available, for example, under the trade names AEROSIL R972, R972V, R974, R812, 200, 200V, 300, R202, OX50 and TT600 (manufactured by Nippon Aerosil Co., And can be used.

The fine particles of zirconium oxide are commercially available, for example, under the trade names AEROSIL R976 and R811 (manufactured by NIPPON AEROSIL CO., LTD.) And can be used.

Examples of the polymer include a silicone resin, a fluororesin, and an acrylic resin. Silicone resin is preferable, and it is particularly preferable to have a three-dimensional network structure. For example, it is commercially available under the trade names of Tosepearl 103, 105, 108, 120, 145, 3120 and 240 And can be used.

Among them, Aerosil 200V and Aerosil R972V are particularly preferably used because they have a large effect of lowering the friction coefficient while keeping the haze of the stretched cellulose ester film low. In the stretched cellulose ester film of the present invention, it is preferable that the coefficient of dynamic friction of at least one surface is in the range of 0.2 to 1.0.

(dyes)

In the stretched cellulose ester film of the present invention, a dye may be added to adjust color taste. For example, a blue dye may be added to suppress the yellowishness of the film. Preferred examples of the dye include anthraquinone dyes.

The anthraquinone-based dye may have an arbitrary substituent at any position from the 1-position to the 8-position of the anthraquinone. Preferred examples of the substituent include an anilino group, a hydroxy group, an amino group, a nitro group or a hydrogen atom. It is particularly preferable to contain the blue dye described in Japanese Patent Laid-Open No. 2001-154017, especially an anthraquinone dye.

The various additives may be added to the dope, which is a solution containing the cellulose ester before the film formation, or may be separately prepared and added in-line. Particularly, in order to reduce the load on the filter medium, the particulate matter is preferably added in a part or in the whole amount.

When the additive solution is added in-line, it is preferable to dissolve it in a small amount of cellulose ester in order to improve the mixing property with the dope. The amount of the cellulose ester is preferably in the range of 1 to 10 parts by mass, more preferably in the range of 3 to 5 parts by mass with respect to 100 parts by mass of the solvent.

In order to perform inline addition and mixing in the present invention, for example, an inline mixer such as a static mixer (manufactured by TORAY ENGINEERING) or an SWJ (Toray stationary type in-line mixer Hi-Mixer) is preferably used.

&Lt; Process for producing stretched cellulose ester film >

Next, the manufacturing method of the stretched cellulose ester film of the present invention will be described in addition to the softening step and the stretching treatment step for controlling the flow rate by the die.

The stretched cellulose ester film of the present invention can be preferably used either as a film produced by the solution casting method or a film produced by the melt casting method.

The preparation of the stretched cellulose ester film of the present invention by the solution softening method includes a step of dissolving the cellulose ester and the additive in a solvent to prepare a dope, a step of softening the dope on an endless metal support to be infinitely shifted, A step of drying as a web, a step of peeling from a metal support, a step of stretching or width holding, a step of drying, and a step of winding a finished film.

The process for producing the dope will be described. The concentration of the cellulose ester in the dope is preferable because it can reduce the drying load after the cellulose ester is soft on the metal support. However, if the concentration of the cellulose ester is too high, the load upon filtration increases and the filtration accuracy deteriorates. The concentrations compatible therewith are preferably in the range of 10 to 35 mass%, and more preferably in the range of 15 to 25 mass%.

The solvent used in the dope may be used alone or in combination of two or more kinds. However, it is preferable to use a mixture of a cellulose ester ester and a poor solvent in view of production efficiency, and both cellulose esters From the viewpoint of solubility. A preferable range of the mixing ratio of the both agent and the poor solvent is within the range of from 70 to 98% by mass and the content of the poor solvent within the range of from 2 to 30% by mass. As the two-component solvent and the low-boiling solvent, the two solvents in which the cellulose ester to be used is solely dissolved are defined as the two solvents, and those that are not swollen or dissolved solely are defined as the poor solvent. Therefore, depending on the average degree of acetalization (degree of acetyl group substitution) of the cellulose ester, both the solvent and the poor solvent are changed. For example, when acetone is used as a solvent, the ester of cellulose ester (acetyl group substitution degree 2.4) Acetate propionate is a biodegradable agent, and an acetic acid ester of cellulose (acetyl group substitution degree 2.8) becomes a poor solvent.

There are no particular restrictions on the two agents, but organic halogen compounds such as methylene chloride, dioxolanes, acetone, methyl acetate, and methyl acetoacetate can be given. Particularly preferred are methylene chloride or methyl acetate.

The poor solvent is not particularly limited, and for example, methanol, ethanol, n-butanol, cyclohexane, cyclohexanone and the like are preferably used. It is preferable that water is contained in the dope in the range of 0.01 to 2 mass%. The solvent used for dissolving the cellulose ester is used by recovering the solvent removed from the film by drying in the film-forming step, and reusing the solvent. In some cases, a small amount of an additive added to cellulose ester such as a plasticizer, an ultraviolet absorber, a polymer, a monomer component and the like is contained in the recovery solvent. However, even if these additives are contained, they can be preferably reused, It can also be reused.

As a method of dissolving the cellulose ester in the preparation of the dope, a general method can be used. When heating and pressurization are combined, heating can be performed at a boiling point or more at normal pressure. It is preferable to stir and dissolve the solvent while heating at a temperature not lower than the boiling point of the solvent at normal pressure and under a pressure range at which the solvent does not boil, thereby preventing the generation of massive solids called gels and agglomerates. Further, a method in which the cellulose ester is mixed with a poor solvent to wet or swell the cellulose ester, followed by further adding a two-component agent to dissolve the cellulose ester is also preferably used.

The pressurization may be performed by a method of injecting an inert gas such as nitrogen gas or a method of raising the vapor pressure of the solvent by heating. The heating is preferably performed from the outside, and for example, a jacket type is preferable because temperature control is easy.

The heating temperature to which the solvent is added is preferably from the viewpoint of the solubility of the cellulose ester, but if the heating temperature is excessively high, the pressure required becomes large and the productivity becomes poor. The heating temperature is preferably in the range of 45 to 120 캜, more preferably in the range of 60 to 110 캜, still more preferably in the range of 70 캜 to 105 캜. The pressure is also adjusted so that the solvent does not boil at the set temperature.

Alternatively, a cooling dissolution method is preferably used, whereby the cellulose ester can be dissolved in a solvent such as methyl acetate.

Next, this cellulose ester solution is filtered using a suitable filter medium such as a filter paper. As the filter medium, it is preferable that the absolute filtration accuracy is small in order to remove insolubles and the like. However, if the absolute filtration accuracy is too small, there is a problem that clogging of the filter medium tends to occur. Therefore, a filter material having an absolute filtration accuracy of 0.008 mm or less is preferable, a filter material having a range of 0.001 to 0.008 mm is more preferable, and a filter material having a range of 0.003 to 0.006 mm is more preferable.

The material of the filter medium is not particularly limited and a normal filter material can be used. However, a plastic filter material such as polypropylene or Teflon (registered trademark) or a metal filter material such as stainless steel is preferable because the fiber does not fall off. It is preferable to remove and reduce impurities contained in cellulose ester as a raw material, in particular, foreign matter by spots by filtration.

The spot foreign matter means two polarizing plates arranged in crossed Nicols state and a stretched cellulose ester film placed therebetween so that light from one side of the polarizing plate and light from the opposite side when viewed from the other side of the polarizing plate Refers to a point (foreign body), and it is preferable that the number of points having a diameter of 0.01 mm or more is 200 pieces / cm ² or less. More preferably 100 pieces / cm ² or less, still more preferably 50 pieces / m ² or less, still more preferably 0 to 10 pieces / cm ² Or less. Further, it is preferable that the luminescent viscosity is 0.01 mm or less.

The filtration of the dope can be carried out by a usual method, but a method of filtration while heating the solvent at a temperature not higher than the boiling point of the solvent under atmospheric pressure and under a pressure not higher than the boiling point is a difference in filtration pressure before and after filtration ) Is small, which is preferable. The preferable temperature is in the range of 45 to 120 占 폚, more preferably in the range of 45 to 70 占 폚, and still more preferably in the range of 45 to 55 占 폚.

The filtration pressure is preferably small. The filtration pressure is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, and further preferably 1.0 MPa or less.

Here, the dope flexing will be described.

The metal support in the casting step preferably has a mirror-finished surface, and as the metal support, a stainless steel belt or a cast iron finish drum is preferably used. The width of the cast may be 1 to 4 m. The surface temperature of the metal support of the softening process is from -50 ° C to the boiling point of the solvent. The higher the temperature, the faster the drying speed of the web. However, if too high, the web may foam or deteriorate in planarity There is a case. The preferred support temperature is in the range of 0 to 40 占 폚, more preferably in the range of 5 to 30 占 폚. Alternatively, the web may be gelled by cooling to peel off the drum in a state containing a large amount of residual solvent. A method of controlling the temperature of the metal support is not particularly limited, but there is a method of blowing hot air or cold air, or a method of bringing hot water to the side of the metal support. Since the heat is efficiently transferred to the use of the hot water, the time until the temperature of the metal support becomes constant is short, which is preferable. In the case of using hot air, a wind having a temperature higher than the target temperature may be used.

In order for the stretched cellulose ester film to exhibit good planarity, the amount of residual solvent when peeling the web from the metal support is preferably in the range of 10 to 150 mass%, more preferably in the range of 20 to 40 mass%, or in the range of 60 To 130% by mass, particularly preferably in the range of 20 to 30% by mass or in the range of 70 to 120% by mass.

In the present invention, the amount of the residual solvent is defined by the following formula.

Amount of residual solvent (mass%) = {(M-N) / N} 100

M is the mass of the sample taken from the web or film at any point during or after the production, and N is the mass after heating the M at 115 占 폚 for 1 hour.

Subsequently, the peeled web is conveyed to the stretching treatment step (preferably a tenter) described above, and the stretching treatment according to the present invention is carried out, and the stretched cellulose ester film is returned to the film drying step.

In the film drying step, the residual solvent amount is preferably 1 mass% or less, more preferably 0.1 mass% or less, and particularly preferably 0 to 0.01 mass% or less.

In the film drying process, generally, a method of roller drying (a method in which a plurality of rollers arranged at upper and lower portions are alternately passed through the web to dry) or a method in which a web is conveyed in a tenter method is used.

The means for drying the web is not particularly limited and generally can be performed by hot air, infrared rays, a heating roller, a microwave or the like, but it is preferable to conduct the air by hot air for simplicity.

The drying temperature in the drying process of the web is preferably in the range of 90 to 200 占 폚, more preferably in the range of 110 to 160 占 폚. It is preferable that the drying temperature is increased stepwise.

The preferred drying time depends on the drying temperature, but is preferably in the range of 5 to 60 minutes, more preferably in the range of 10 to 30 minutes.

The film thickness of the stretched cellulose ester film is not particularly limited, but is preferably in the range of 10 to 200 占 퐉, more preferably in the range of 10 to 100 占 퐉, still more preferably in the range of 30 to 70 占 퐉 Within the range.

The stretched cellulose ester film of the present invention is used in a range of 2 to 4 m in width, more preferably in a range of 2 to 3 m. If it exceeds 4 m, it becomes difficult to transport.

The stretched cellulose ester film is preferably thermally fixed after the stretching treatment described above. It is preferable that the thermosetting is performed within a temperature range of Tg-20 占 폚 or less and usually within a range of 0.5 to 300 seconds. At this time, it is preferable that heat-setting is performed while sequentially raising the temperature in a range where the temperature difference is in the range of 1 to 100 占 폚 in the region divided into two or more parts.

The heat-set film is usually cooled to below Tg, and the clip gripping portions at both ends of the film are cut and wound. It is preferable that the cooling is progressively cooled from the final heat fixing temperature to the Tg at a cooling rate of 100 DEG C or less per second. The means for cooling and relaxation is not particularly limited and can be carried out by conventionally known means. In particular, it is preferable from the viewpoint of improving the dimensional stability of the film that these treatments are carried out sequentially while cooling in a plurality of temperature ranges.

More optimal conditions for these heat fixing conditions, cooling, and relaxation treatment conditions are different depending on additives such as cellulose ester and plasticizer constituting the film. Therefore, the physical properties of the obtained stretched film are measured and appropriately adjusted .

When the slow axis or the fast axis of the stretched cellulose ester film of the present invention is present in the film surface and the angle formed with the film forming direction is? 1,? 1 is preferably -1 degrees or more and +1 degrees or less, more preferably -0.5 degrees or more + Is more preferable. This? 1 can be defined as an orientation angle, and the measurement of? 1 can be performed using an automatic birefringence system KOBRA-21ADH (Oji Keisoku Kiki). and? 1 satisfy the above-described relationships can contribute to obtaining a high luminance in a display image and contributing to suppressing or preventing light leakage, and contributing to obtaining faithful color reproduction in a color liquid crystal display device.

<Properties>

(Refractive index control)

In the stretched cellulose ester film of the present invention, it is also an important operation to adjust the retardation by stretching. The stretched cellulose ester film of the present invention preferably has an in-plane retardation value Ro in the range of 0 to 20 nm and a retardation value Rt in the thickness direction within a range of -100 to 100 nm, More preferably, it is in the range of Ro? 5 nm and -30 nm? Rt? 30 nm.

In this case, the retardation value Ro in the in-plane direction is in the range of 30 to 100 nm and the retardation value Rt in the thickness direction is in the range of 70 to &lt; RTI ID = 0.0 &gt; Preferably within a range of 400 nm to 400 nm.

Formula _{(i) Ro = (n x} -n y) × d

Formula (ii) Rt = ((n x + n y) / 2-n z) × d

(Where n _x is refractive index in the slow axis direction in the film plane, n _y is refractive index in the fast axis direction in the film plane, n _z is refractive index in the thickness direction of the film, and d is the thickness (nm)

The refractive index can be obtained at a wavelength of 590 nm under an environment of 23 ° C and 55% RH using, for example, KOBRA-WR (Oji Keisei Kikuchi).

(Other properties)

The moisture permeability of the stretched cellulose ester film of the present invention is preferably in the range of 10 to 1200 g / m ² 24 ²⁴ h at 40 캜 and 90% RH, more preferably in the range of 20 to 1000 g / m ² 24 ²⁴ h, / m &lt; ² &gt; The moisture permeability can be measured according to the method described in JIS Z 0208.

The visible light transmittance of the stretched cellulose ester film of the present invention is preferably 90% or more, more preferably 93% or more.

The haze of the stretched cellulose ester film of the present invention is preferably less than 1%, particularly preferably in the range of 0 to 0.1%.

<Polarizer>

A polarizing plate using the stretched cellulose ester film of the present invention and a liquid crystal display using the polarizing plate will be described.

The polarizing plate joins the stretched cellulose ester film of the present invention to at least one surface of the polarizer.

The polarizing plate can be manufactured by a general method. It is preferable to bond the polarized film on the polarizer side of the stretched cellulose ester film of the present invention by alkali saponification treatment and immersion stretching in iodine solution on at least one side of the polarizer using a fully saponified polyvinyl alcohol aqueous solution. On the other side, the stretched cellulose ester film may be used, or another optical film may be used. KC4UY, KC8UR, KC8UCR-3, KC8UCR-4, KC8UCR-5, KC4FR-1, KC8UY-HA, KC8UX-RHA, KC4UY, KC4UY, KC4UX, KC4UX, KC4UX, , KC6UA (manufactured by Konica Minolta Opto Co., Ltd.) are also preferably used.

For example, in the stretched cellulose ester film of the present invention, when the in-plane retardation value Ro is in the range of 0 to 20 nm and the retardation value Rt in the thickness direction is in the range of -100 to 100 nm, The retardation value Ro in the in-plane direction measured at a wavelength of 590 nm is within a range of 20 to 100 nm and the retardation value Rt in the thickness direction is within a range of 70 to 300 nm It is preferably an optical film.

The optical film having the retardation function is not particularly limited, and can be manufactured by the method described in, for example, Japanese Patent Laid-Open Nos. 2005-196149 and 2005-275104. It is also preferable to use an optical film also serving as an optical compensation film having an optically anisotropic layer formed by aligning a liquid crystal compound such as a discotic liquid crystal. For example, an optically anisotropic layer can be formed by the method described in Japanese Patent Application Laid-Open No. 2005-275083. By using an optical film having the retardation function in combination, a polarizing plate and a liquid crystal display device having a stable viewing angle magnification effect can be obtained.

The polarizer, which is a main component of the polarizing plate, is a device that passes only light of a polarization plane in a certain direction. A typical polarizer currently known is a polyvinyl alcohol polarizing film. This is a film obtained by dyeing a polyvinyl alcohol film with iodine, Some dye is dyed. The polarizer is preferably a film obtained by forming a polyvinyl alcohol aqueous solution, uniaxially stretching it, dyeing it, uniaxially stretching it, and preferably durability treatment with a boron compound. The thickness of the polarizer is preferably in the range of 5 to 30 mu m, more preferably in the range of 10 to 20 mu m.

The content of the ethylene unit in the range of 1 to 4 mol%, the degree of polymerization in the range of 2,000 to 4,000, and the content of the ethylene units described in Japanese Patent Application Laid-Open Nos. 2003-248123 and 2003-342322, Ethylene-modified polyvinyl alcohol having a degree of 99.0 to 99.99 mol% is also preferably used. Among them, an ethylene-denatured polyvinyl alcohol film having a hot water cutting temperature in the range of 66 to 73 占 폚 is preferably used. The difference in hot water cutting temperature between two points spaced by 5 cm in the TD direction of the film is more preferably 1 ° C or less in terms of reducing color unevenness and the difference in hot water cutting temperature between two points spaced by 1 cm in the TD direction of the film 0.5 DEG C or less is more preferable in terms of reducing color unevenness.

The polarizer using the ethylene-denatured polyvinyl alcohol film has excellent polarizing performance and durability, and is uneven in color and is particularly preferably used for a large-sized liquid crystal display device.

The polarizer obtained as described above is generally used as a polarizer by bonding a protective film to both surfaces or one side of the polarizer. Examples of the adhesive used for the bonding include a PVA adhesive and a urethane adhesive. Among them, a PVA adhesive Is preferably used.

<Liquid Crystal Display Device>

By incorporating the polarizing plate into a display device, a liquid crystal display device having excellent visibility can be manufactured. Liquid crystal display devices of various types such as TN type, STN type, OCB type, VA type, IPS type and ECB type, VA type (MVA type, PVA type) liquid crystal display device.

Since the retardation value Ro in the in-plane direction of the stretched cellulose ester film of the present invention fluctuates little in the width direction, the polarizing plate using the polarizing plate has good visibility even when used in a large screen liquid crystal display device, Can be given.

In the liquid crystal display device having a screen of 17-inch or larger size, especially a screen of 30-inch or larger size, there is no distortion such as color unevenness or wavy unevenness, and therefore, there is an effect that eyes do not become tired even for a long time.

<Examples>

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

Example 1

&Lt; Preparation of stretched cellulose ester film 1 >

<Fine Particle Dispersion 1>

11 parts by mass of fine particles (Aerosil R812V manufactured by Nippon Aerosil Co., Ltd.)

Ethanol 89 parts by mass

The resulting mixture was stirred with a dissolver for 50 minutes and dispersed with Manton-Gaulin.

&Lt; Fine Particle Addition Solution 1 >

The fine particle dispersion 1 was slowly added to the dissolution tank containing methylene chloride while sufficiently stirring. Further, the particles were dispersed in the attritor so that the particle diameter of the secondary particles became a predetermined value. This was filtrated with Fine Mat NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle addition liquid 1.

99 parts by mass of methylene chloride

Fine particle dispersion 1 5 parts by mass

The main doping of the following composition was prepared. First, methylene chloride and ethanol were added to the pressure-melting tank. A cellulose acetate solution having an acetyl group substitution degree of 2.60 was added to a pressurized dissolution tank containing a solvent with stirring. This was completely dissolved while heating and stirring. This was filtered using Azumi Rossi No.244 manufactured by Azumi Co., Ltd. to prepare a main dope.

<The composition of main dop>

550 parts by mass of methylene chloride

40 parts by mass of ethanol

Cellulose acetate (acetyl group degree of substitution: 2.60, weight average molecular weight: 260,000)

100 parts by mass

Triphenylphosphate 10 parts by mass

5 parts by mass of ethyl phthalyl ethyl glycolate

Fine particle addition liquid 1 5 parts by mass

Tinuvin 928 (manufactured by BASF Japan) 2.6 parts by mass

Was added to a sealed container and dissolved while stirring to prepare a dope. Subsequently, the dope was softened to have a uniform film thickness on the stainless steel belt support at a temperature of 33 DEG C and a width of 1600 mm by using an endless belt softening apparatus. The temperature of the stainless steel belt was controlled at 30 占 폚.

On the stainless steel belt support, the solvent was evaporated until the amount of residual solvent in the cast (cast) film was 75%, and then peeled off from the stainless belt support with a peel tension of 130 N / m.

The peeled cellulose acetate film was adjusted by adjusting the temperature of the housing 10 using the tenter shown in Fig. 3 to adjust the stretching temperature of the film surface to 170 占 폚 and stretching the stretched film at a stretching ratio of 35% in the transverse direction .

The surface temperature of the film end portion and the center portion was measured using a contact type handy thermometer (ANRITSU DIGITAL THERMOMETER HA-100K) at five points in the width direction of the film being transported, and the average value was taken as the surface temperature of the portion.

Subsequently, drying was terminated while the drying zone was transported at a high speed by a plurality of rollers, and the end slits were made so as to have a desired product width and then wound. The drying temperature was 130 占 폚, and the conveying tension was 100 N / m.

Thus, a stretched cellulose ester film 1 having a film width of 1490 mm, a dried film thickness of the film terminal end of 60 mu m and a length of 5000 m was produced.

The film thickness of the finished stretched cellulose ester film 1 was measured at intervals of 10 cm from the end portion in the width direction using a contact type film thickness measuring instrument (Micrometer Minicom M manufactured by Tokyo Seimitsu Co., Ltd.) h (maximum film thickness - end film thickness) was found to be 0.5 탆. In addition, whether or not the film thickness measurement value is represented by a suspension curve was judged by a regression equation, and it was not represented by a suspension curve.

&Lt; Preparation of stretched cellulose ester film 2 >

The elongated cellulose ester film 2 was prepared in the same manner as in the preparation of the stretched cellulose ester film 1 except that the dope was made flexible so as to have a uniform film thickness on the stainless steel belt support at a temperature of 33 ° C and a width of 2,400 mm and a finishing film width of 2300 mm. Respectively.

The film thickness of the finished stretched cellulose ester film 1 was measured at intervals of 10 cm from the end portion in the width direction using a contact type film thickness measuring instrument (Micrometer Minicom M manufactured by Tokyo Seimitsu Co., Ltd.) h (maximum film thickness - end film thickness) was found to be 0.5 탆. In addition, whether or not the film thickness measurement value is represented by a suspension curve was judged by a regression equation, and it was not represented by a suspension curve.

&Lt; Preparation of stretched cellulose ester film 3 >

Except that in the production of the stretched cellulose ester film 2, the slit gap of the dicing sleeve member was flexible so that the central portion became thicker than the end portion in such a manner that the film thickness became approximate to the hanging curve when the dope was softened on the stainless steel belt support, To prepare an ester film 3.

The film thickness of the finished stretched cellulose ester film 3 was measured at intervals of 10 cm from the end portion in the width direction using a contact type film thickness measuring instrument (Micrometer Minicom M manufactured by Tokyo Seimitsu Co., Ltd.) h (maximum film thickness-end film thickness) was found to be 1.5 占 퐉. In addition, whether the film thickness measurement value is represented by a suspension curve or not is determined by a regression equation, and it is represented by a suspension curve.

&Lt; Preparation of stretched cellulose ester film 4 >

The composition of the main doping was changed as follows.

<The composition of main dop>

550 parts by mass of methylene chloride

40 parts by mass of ethanol

Cellulose acetate (acetyl group degree of substitution: 2.85, weight average molecular weight: 270000)

100 parts by mass

8 parts by mass of a sugar ester plasticizer (Exemplary Compound 1-7)

5 parts by mass of an aromatic terminal ester plasticizer (Exemplary Compound 2-16)

Fine particle addition liquid 1 5 parts by mass

Tinuvin 928 (manufactured by BASF Japan) 2.6 parts by mass

In the same manner as in the production of the stretched cellulose ester film 3, when the gap between the slits of the spinneret member of the dice was softened on the stainless steel belt support, the film was flexible so that the film thickness became thicker at the center than the end, To prepare an oriented cellulose ester film 4.

The film thickness of the finished stretched cellulose ester film 4 was measured at intervals of 10 cm from the end portion in the width direction using a contact type film thickness measuring instrument (Micrometer Minicom M manufactured by Tokyo Seimitsu Co., Ltd.) h (maximum film thickness-end film thickness) was found to be 1.5 占 퐉. In addition, whether the film thickness measurement value is represented by a suspension curve or not is determined by a regression equation, and it is represented by a suspension curve.

&Lt; Preparation of stretched cellulose ester films 5 and 6 >

In the preparation of the stretched cellulose ester film 4, stretched cellulose ester films 5 and 6 were prepared in the same manner, except that the film thickness of the central portion and the end portion was adjusted by changing the slit gap of the dicing member of the die so as to satisfy the conditions described in Table 2 .

The film thicknesses of the finished stretched cellulose ester films 5 and 6 were measured at intervals of 10 cm from the ends in the width direction using a contact type film thickness measuring instrument (Micrometer Minicom M manufactured by Tokyo Seimitsu Co., Ltd.) The thickness difference h (maximum film thickness-end film thickness) was obtained, and the value shown in Table 2 was obtained. In addition, whether the film thickness measurement value is represented by a suspension curve or not is determined by a regression equation, and it is represented by a suspension curve.

&Lt; Preparation of stretched cellulose ester film 7 >

In the preparation of the stretched cellulose ester film 4, the temperature of the housing 10 was adjusted by using the tenter shown in Fig. 2 on the peeled unstretched cellulose acetate film, and the stretching temperature of the film surface was adjusted to 170 캜 , And an end cold room generating portion G1 was provided at a position shown in Fig. 5, and the stretched cellulose ester film 7 was stretched by 45% in the width direction while adjusting the temperature so that the film end surface had a stretching temperature of 155 캜.

The film thickness of the finished stretched cellulose ester film 7 was measured at intervals of 10 cm in the width direction from the end portion using a contact type film thickness measuring instrument (Micrometer Minicom M manufactured by Tokyo Seimitsu Co., Ltd.) h (maximum film thickness-end film thickness) was obtained. In addition, whether the film thickness measurement value is represented by a suspension curve or not is determined by a regression equation, and it is represented by a suspension curve.

&Lt; Preparation of stretched cellulose ester films 8 to 12 >

Except that the cellulose ester acetyl group degree of substitution, film maximum film thickness, film end film thickness, finish width, and stretching temperature were changed as shown in Table 2 in the preparation of the stretched cellulose ester film 7, the stretched cellulose ester film 8 to 12 Respectively.

The film thicknesses of the finished stretched cellulose ester films 8 to 12 were measured at intervals of 10 cm in the width direction from the ends using a contact type film thickness measuring instrument (Micrometer Minicom M manufactured by Tokyo Seimitsu Co., Ltd.) The thickness difference h (maximum film thickness-end film thickness) was obtained, and the value shown in Table 2 was obtained. In addition, whether the film thickness measurement value is represented by a suspension curve or not is determined by a regression equation, and it is represented by a suspension curve.

&Lt; Preparation of stretched cellulose ester film 13 >

In the production of the stretched cellulose ester film 9, the stretched cellulose ester film 13 was obtained in the same manner as in Example 1 except that the end cold-weather-generating portion G1 shown in Fig. 5 was provided only in the central portion and the temperature in the central portion was lowered by 30 deg. Respectively.

The film thickness of the finished stretched cellulose ester film 13 was measured at intervals of 10 cm from the end portion in the width direction using a contact type film thickness measuring instrument (Micrometer Minicom M manufactured by Tokyo Seimitsu Co., Ltd.) h (maximum film thickness - end film thickness) was found to be 5.3 탆. In addition, whether or not the film thickness measurement value is represented by a suspension curve was judged by a regression equation, and it was not represented by a suspension curve.

"evaluation"

The following evaluations were performed on the prepared stretched cellulose ester films 1 to 13.

(Measurement of arithmetic mean roughness (Ra)) [

The average value of the arithmetic average roughness Ra of the ends was selected in the longitudinal direction with respect to the end portion of the film (area H in Fig. 3), and the arithmetic average roughness Ra was measured.

The average value of the arithmetic average roughness Ra of the central portion was selected in the longitudinal direction with respect to the center portion (the area T in Fig. 3), and the arithmetic average roughness Ra was measured.

The arithmetic average roughness (Ra) was measured by using a non-contact surface fine-shape measuring apparatus WYKO HD3300 according to JIS B 0601. [

(Slit suitability in high-speed transportation)

The slit suitability at the time of high-speed conveyance was evaluated under the following high-speed conditions at a high-speed condition of 1.3 times the film conveying speed under the reference condition.

◎: No notch failure occurred at high speed

○: When a high-speed transport is performed, the notch defect rarely occurs

△: Notch failure frequently occurred at high speed transport

X: Frequent breakage of notch after high-speed transport

Practical allowable range is ◯ or more.

(Fluctuation of Ro)

Ten samples were taken from each of the end portions and the central portion of the prepared stretched cellulose ester film, and the samples were measured at a wavelength of 590 nm in an in-plane direction at 23 ° C and 55% RH using KOBRA-WR (Oji Keisei Kikuchi) The retardation value Ro was measured, and the average value of the retardation value Ro at the center portion and the end portion was obtained. Subsequently, the car was evaluated by the following evaluation criteria.

Formula _{(i) Ro = (n x} -n y) × d

(Where n _x is refractive index in the slow axis direction in the film plane, n _y is refractive index in the fast axis direction in the film plane, and d is the thickness (nm) of the film)

A: Difference between (central portion and end) less than 0.5 nm

B: a difference in (central portion to end) from 0.5 nm to less than 1.0 nm

C: Difference between (central portion and end) 1.0 nm or more and less than 2.0 nm

D: a difference of (center portion to end portion) of 2.0 nm or more

Practical allowable range is B or more.

The composition and evaluation results of the above elongated cellulose ester film are shown in Tables 2 and 3.

From the results shown in Tables 2 and 3, it is understood that the stretched cellulose ester film of the present invention is excellent in slit suitability at the time of high-speed conveying even when the stretched cellulose ester film of the comparative example is widened, It was found that the variation of the optical characteristics was also excellent because the fluctuation of the retardation value Ro was small.

Example 2

<Production of polarizing plate>

The prepared stretched cellulose ester films 1 to 13 were subjected to alkali treatment for 60 seconds with a 2.5 mol / L aqueous solution of sodium hydroxide at 40 占 폚, followed by washing with water for 3 minutes to obtain an alkali-treated film.

Subsequently, a polyvinyl alcohol film having a thickness of 120 占 퐉 was uniaxially stretched (temperature: 110 占 폚, stretching magnification: 5 times). This was immersed in an aqueous solution containing 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, and subsequently immersed in an aqueous solution of 68 DEG C comprising 6 g of potassium iodide, 7.5 g of boric acid and 100 g of water. This was washed with water and dried to obtain a long polarizer.

Next, each of the stretched cellulose ester films 1 to 13 was bonded to both surfaces of a polarizer using a 5% aqueous solution of completely saponified polyvinyl alcohol as an adhesive to prepare polarizers 1 to 13.

(Fabrication of liquid crystal display device)

A liquid crystal panel for performing viewing angle measurement was manufactured as follows to evaluate the characteristics as a liquid crystal display device.

The polarizing plate on the side of the viewer which had been preliminarily bonded to the 40-inch type display KLV-40J3000 of VA mode liquid crystal display device was peeled off and the polarizing plates 1 to 13 were bonded to the glass surface of the liquid crystal cell so that the absorption axes of the polarizing plates coincided A VA mode liquid crystal display device was manufactured, and color unevenness and frontal contrast were visually evaluated.

As a result, the polarizing plate and the liquid crystal display device using the stretched cellulose ester film of the present invention are polarizing plates and liquid crystal display devices which are free of color unevenness and excellent in front contrast because the fluctuation of the retardation value Ro in the in- Could know.

&Lt; Industrial applicability >

The stretched cellulose ester film of the present invention suppresses the disturbance of the cellulose orientation even when the film is stretched at a high magnification and is not likely to cause notch failure even at a high speed, And thus can be suitably used for a polarizing plate protective film and an optical film for a liquid crystal display device.

A: A side
B: B side
Mh: Maximum film thickness
Lh: end membrane thickness
K: Suspension curve
W, Fo: unstretched cellulose ester film (web)
F: stretched cellulose ester film
1: Stainless steel endless belt (support)
3: peeling roller
4: Tentor
5: Drying device
6: conveying roller
8:
10: Housing
11: Clip
12: Rail
G1, G2: End cold air generation part

Claims (6)

A stretched cellulose ester film containing a cellulose ester having an acetyl group degree of substitution in the range of 2.8 to 2.95, wherein the A-side is a stretched cellulose ester film obtained by stretching the stretched cellulose ester film on the surface A when the film is flexible on a belt or drum (The film maximum film thickness - the film end film thickness) is 1.0 or more, and the film thickness difference h (film maximum film thickness - film end film thickness) is 1.0 To 4.0 m,
The arithmetic average roughness (the center portion in this case, the total width of the stretched cellulose ester film is referred to as L in the width direction from the center portion of the film when the entire width of the stretched cellulose ester film is referred to as the portion of the stretched cellulose ester film in A side) Ra) is in the range of 2.2 to 3.5 nm, and an end portion of the stretched cellulose ester film on the surface A (where the end portion means the total width of the stretched cellulose ester film is L, 0.05) of the elongated cellulose ester film is 0.3 to 1.0 nm higher than the average value of the arithmetic mean roughness (Ra) of the stretched cellulose ester film. delete The stretched cellulose ester film according to claim 1, wherein the stretched cellulose ester film has a width of 2 to 3 m and a maximum film thickness of 30 to 70 탆. A process for producing a stretched cellulose ester film according to claim 1, wherein the dope for forming the stretched cellulose ester film is a flexible film on a belt or drum as shown by a part of the cross- And the end portion on the A side of the web after peeling is referred to as an end portion of the film or a portion of Lo x 0.05 when the entire width of the unstretched cellulose ester film is Lo The surface temperature is set at a value of 10 to 50 占 폚 relative to the surface temperature of the center portion (here, the central portion refers to a portion of 占 L 占 0.1 in the width direction from the center portion of the film when the entire width of the unstretched cellulose ester film is taken as Lo) Wherein the stretching treatment is carried out while the film is kept at a low level within a range of from 0.1 to 10% by weight. 5. The apparatus according to claim 4, wherein at least one pair of cold air generating portions is provided for adjusting the surface temperature of the end portion, and a temperature lower than the temperature of the central portion in a range of 10 to 50 DEG C Is stretched while spraying the cold wind of the stretched cellulose ester film on the end portion. The method according to claim 4 or 5, characterized in that the stretching is carried out in the film width direction at a stretching magnification in the range of 160 to 190 캜 and in the range of 25 to 100% A method for producing an elongated cellulose ester film.

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