KR20180122659A - Method for producing optical film - Google Patents

Abstract

The production method of the optical film includes a stirring preparation process and a pouring process. The specific gravity of the resin to be stirred is A, the specific gravity of the solvent is B, and the specific gravity difference (B-A) is Δ, 0.1 <Δ <0.5. The first stirring jig 111 has a first rotating shaft 112 and an arm portion 113. The second stirring jig 121 has a second rotating shaft 122 and a first stirring blade 123a and a second stirring blade 123b. When the length along the vertical direction of the arm portion 113 is L, the first stirring vane 123a is positioned at a position A vertically downward (1/3) L from the uppermost portion 113a of the arm portion 113 And is located higher than that. The second stirring vane 123b is located below the position A. [

Description

Method for producing optical film

The present invention relates to a method for producing an optical film for film formation of an optical film by a solution casting film forming method, and more particularly to stirring of a dope which is flexible on a support.

Conventionally, as an agitating device for stirring a solution, for example, there is one disclosed in Patent Document 1. In this stirring apparatus, in the stirring tank into which the solution is injected, the first flat plate wing member and the second flat plate wing member are attached side by side along the rotational axis direction to the rotating shaft extending in the vertical direction. The first flat plate wing member and the second flat plate wing member are attached to the rotary shaft at an inclined angle to raise the solution based on the rotation of the rotary shaft. By rotating the first flat plate wing member and the second flat plate wing member about the rotation axis, the circulating flow of the solution is generated without being divided in the vertical direction of the stirring tank, so that the circulation mixing of the solution can be performed efficiently .

Japanese Patent Application Laid-Open No. 2010-42337 (see claim 1, paragraphs [0001], [0004], [0007], Figures 1 and 2, etc.)

However, when the stirring apparatus of Patent Document 1 is applied to the stirring of the resin and the solvent when preparing the dope used in the solution casting method, and the optical film is formed by using the dope prepared by stirring, It was confirmed that the thickness irregularity and foreign matters were generated. In view of these causes, the present inventors assume as follows.

Since the first and second flat blade members of the stirring apparatus are composed of the stirring blades for generating the upstream and downstream of the stirring, the stirring by the upward and downward circulation is possible, Horizontal direction, shear direction) can not be efficiently performed. As a result, irregularities occur in the stirring in the stirring tank, and the unevenness of the stirring causes the viscosity of the dope to become unstable, and film thickness irregularity occurs in the optical film to be formed using such a dope. In addition, if stirring irregularity occurs, the resin is agglomerated in the stirring tank to cause aggregation (unheated product) and other defective dissolution. When an optical film is formed by using a dope containing an unseasoned product, the unsealed product appears as a foreign object in the optical film.

Particularly, when a pellet-shaped resin (for example, an acrylic resin) having a small specific gravity is dissolved in a solvent having a high specific gravity (e.g., methylene chloride), the resin tends to float on the surface of the liquid to cause agglomeration, As a result of which the lumps remain as an untreated product, a foreign object is easily generated in the formed optical film.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problem, and an object of the present invention is to provide an optical film capable of reducing irregularity in stirring in a stirring tank and thereby reducing unevenness of film thickness of an optical film to be formed, And a method for producing the same.

The above object of the present invention is achieved by the following production method.

That is, a method for producing an optical film according to one aspect of the present invention is a method for producing an optical film by a solution casting method,

A stirring and mixing step of stirring at least a resin and a solvent in a stirring tank to prepare a dope,

And a softening step of softening the dope prepared in the stirring and mixing step on a support,

The resin is any one of an acrylic resin, a cycloolefin resin, and a polyarylate resin,

The specific gravity of the resin is represented by A, the specific gravity of the solvent is represented by B, and the specific gravity difference (B-A)

0.1 <

Lt;

In the stirring tank, a first stirring jig and a second stirring jig are provided,

Wherein the first stirring jig includes a first rotary shaft located on a vertical axis passing through the center of the bottom surface of the stirring tank and a second rotary shaft located above the lowermost portion in the stirring tank from the lowermost portion of the first rotary shaft, And an arm portion extending to a position spaced apart in a turning radial direction from the arm portion,

The second stirring jig includes the second rotation shaft extending in the vertical direction so as to pass through the space between the first rotation shaft and the arm portion and at least two stirring wings attached to the second rotation shaft so as to be arranged along the vertical direction Have,

A length of the arm portion of the first stirring jig is L and a stirring blade of the uppermost one of the at least two stirring blades of the second stirring jig and a stirring blade located below the one of the at least two stirring blades of the second stirring jig are respectively referred to as first When a stirring blade and a second stirring blade are used,

Wherein the first stirring vane is located above and including a position vertically downward by 1/3 L from the uppermost portion of the arm portion of the first stirring jig and is rotated by the rotation about the second rotation axis And a stirring blade for causing a flow of the resin in the vertical direction,

Wherein the second stirring blade is located below a position vertically downwardly downward by (1/3) L from the uppermost portion of the arm portion of the first stirring jig, and by rotation about the second rotation axis, And a stirring blade for causing a flow of the resin drawn vertically downward by a stirring blade in a direction perpendicular to the second rotation axis.

According to the above production method, it is possible to reduce stirring irregularities in the stirring tank, thereby making it possible to reduce uneven film thickness of the optical film to be formed and occurrence of foreign objects.

1 is an explanatory view showing a schematic structure of an optical film production apparatus according to an embodiment of the present invention.
2 is a flow chart showing the flow of the production process of the optical film.
3 is a cross-sectional view schematically showing an example of a stirring apparatus having a first stirring jig.
4 is a cross-sectional view showing another configuration of the first stirring jig.
5 is a perspective view showing still another structure of the first stirring jig.
6 is a perspective view showing still another structure of the first stirring jig.
7 is a perspective view showing still another structure of the first stirring jig.
8 is a perspective view showing a configuration example of a first stirring blade of a second stirring jig included in the stirring device;
9 is a perspective view showing another configuration example of the first stirring vane.
10 is a perspective view showing a configuration example of a second stirring blade of the second stirring jig.
11 is a perspective view showing another configuration example of the second stirring vane.
12 is a cross-sectional view showing another configuration of the second stirring jig.
13 is a cross-sectional view showing a configuration example of a stirring apparatus used in the embodiment.
14 is a cross-sectional view showing another configuration example of the stirring device.
15 is a cross-sectional view showing still another example of the structure of the stirring device.
16 is a cross-sectional view showing still another example of the structure of the stirring device.
17 is a cross-sectional view showing still another example of the structure of the stirring device.
18 is a cross-sectional view showing still another example of the stirring device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the drawings. In this specification, when numerical ranges are denoted by A to B, values of lower limit A and upper limit B are included in the numerical range.

[Production method of optical film]

1 is an explanatory view showing a schematic structure of an optical film production apparatus 1 of the present embodiment. 2 is a flowchart showing the flow of the manufacturing process of the optical film. As shown in Fig. 2, the optical film production method of this embodiment is a method of producing an optical film by a solution casting film forming method and includes a stirring preparation step S1, a softening step S2, a peeling step S3 ), A stretching step (S4), a drying step (S5), a cutting step (S6), an embossing step (S7), and a winding step (S8). Hereinafter, each step will be described with reference to Figs. 1 and 2. Fig.

<Stirring preparation process>

In the stirring and dispensing step, at least the resin and the solvent are stirred by the stirring tank 101 of the stirring apparatus 100 to prepare a dope which is flexible on the support 3 (endless belt). Details of the stirring apparatus 100 will be described later.

<Flexible Process>

In the flexible process, a support 3 including a rotary-driven stainless steel endless belt for feeding the dope prepared in the stirring and mixing process to the flexible die 2 through a conduit through a pressurized metering gear pump or the like, At the flexible position above, the dope is flexible from the flexible die 2, thereby forming a web 5 as a flexible film on the support 3.

The support 3 is held by a pair of rolls 3a and 3b and a plurality of rolls (not shown) located therebetween. On one or both sides of the rolls 3a and 3b, a driving device (not shown) for applying a tension to the supporting body 3 is provided, whereby the supporting body 3 is used in a state in which tension is applied.

In the flexible process, when the web 5 formed by the dope softened on the support 3 is heated on the support 3 and the web 5 is peelable by the peeling roll 4 from the support 3 To evaporate the solvent. In order to evaporate the solvent, there are a method of generating air from the web side, a method of transferring heat from the back surface of the support 3 by liquid, a method of transferring heat from the front and back by radiant heat, do.

<Peeling process>

In the above-mentioned softening step, the web 5 is dried and solidified or cooled and solidified until the web 5 becomes peelable film strength on the support 3, and then in the peeling step, the web 5 is peeled off with a self- (4).

The amount of the residual solvent in the web 5 on the support 3 at the time of peeling is preferably in the range of 50 to 120 mass%, depending on the strength of the drying condition, the length of the support 3 and the like. If the web 5 is too soft when it is peeled off at a point where the amount of residual solvent is larger, the planarity is deteriorated when peeling off, and wrinkles or vertical stripes are liable to occur due to peeling tension. The amount of residual solvent in the solvent is determined. Further, the amount of residual solvent is defined by the following formula.

(Mass%) = (mass before heat treatment of web-mass after heat treatment of web) / (mass after heat treatment of web) 占 100

Here, the heat treatment at the time of measuring the residual solvent amount means that the heat treatment is performed at 115 캜 for one hour.

<Stretching Step>

In the stretching step, the web 5 peeled off from the support 3 is stretched by the tenter 6. The stretching direction at this time is either the machine direction (MD direction) or the transverse direction (TD direction; transverse direction) perpendicular to the transport direction in the film plane. In the stretching process, a tenter system in which both side edges of the web 5 are fixed with a clip or the like and stretched is preferable because it improves the planarity and dimensional stability of the film. In addition, in the tenter 6, drying may be performed in addition to drawing. In the stretching process, the web 5 may be stretched (obliquely stretched) in a direction crossing obliquely with respect to the MD and TD directions by stretching the web 5 in both the MD and TD directions.

(Drying step)

The web 5 stretched by the tenter 6 is dried by the drying device 7. In the drying apparatus 7, the web 5 is transported by a plurality of transport rolls arranged in a staggered shape when viewed from the side, and the web 5 is dried therebetween. The drying method in the drying apparatus 7 is not particularly limited, and generally, the web 5 is dried using hot air, infrared rays, a heating roll, a microwave, or the like. From the viewpoint of simplicity, a method of drying the web 5 with hot air is preferred.

The web 5 is dried by the drying device 7 and then transported toward the winding device 10 as an optical film F.

(Cutting process, embossing process)

Between the drying device 7 and the winding device 10, a cutting portion 8 and an embossing portion 9 are arranged in this order. The cutting section 8 carries out a cutting step of cutting both ends in the width direction of the formed optical film F by a slitter while conveying the formed optical film F. [ In the optical film F, the portions left after cutting at both ends constitute a product portion which is a film product. On the other hand, the portion cut from the optical film F is recovered by the shooter, and is reused as a part of the raw material for film formation.

After the cutting process, embossing (knurling) is performed on both end portions in the width direction of the optical film F by the embossing portion 9. The embossing is performed by pressing the heated embossing rollers against both ends of the optical film F. [ Concave and convex portions are formed on both ends of the optical film F by pressing the embossing roller against the both end portions of the optical film F. By embossing in this manner, winding displacement and blocking (adhesion between films) in the next winding step can be suppressed as much as possible.

(Winding process)

Finally, the optical film F which has been subjected to emboss processing is wound up by the winding device 10 to obtain a basic roll (film roll) of the optical film F. That is, in the winding step, the optical film F is wound and wound on the winding core while the film F is being conveyed, thereby producing a film roll. As a method for winding the optical film F, a commonly used winder may be used, and there is a method of controlling the tension such as a constant torque method, a constant tension method, a taper tension method, and an internal stress constant program tension control method. You can use it. The winding length of the optical film F is preferably 1000 to 7200 m. The width at that time is preferably 1000 to 3200 mm, and the film thickness is preferably 10 to 60 mu m.

[About the stirring apparatus]

Next, the stirring apparatus 100 used in the above-described stirring and mixing process will be described. 3 is a cross-sectional view schematically showing an example of the stirring apparatus 100. As shown in Fig. The first stirring jig 111 and the second stirring jig 121 are provided in the stirring tank 101 of the stirring apparatus 100. For the sake of convenience in the following description, the bottom surface 101a side of the stirring tank 101 is referred to as &quot; below &quot;, and the top surface 101b side is referred to as &quot; top &quot;. A direction in which the bottom surface 101a and the ceiling surface 101b face each other is referred to as a vertical direction (vertical direction), and a direction perpendicular to the vertical direction is referred to as a horizontal direction.

The first stirring jig 111 has a first rotating shaft 112 and an arm portion 113 and only one is provided in the stirring tank 101. The first rotating shaft 112 is positioned on the vertical axis AX passing through the center O of the bottom surface 101a of the stirring tank 101. [ The first rotary shaft 112 is connected to a driving source (for example, a motor) not shown, and is rotated by driving the driving source. The rotation speed of the first rotation shaft 112 (= rotation speed of the first stirring jig 111) is appropriately adjusted in the range of 5 to 100 rpm, for example.

The arm portion 113 is located at a position higher than the lowermost portion 112a in the stirring tank 101 from the lowermost portion 112a which is the lower end portion of the first rotary shaft 112, And is attached to the first rotation shaft 112 so as to extend to the uppermost portion 113a at a position spaced apart from the first rotation shaft 112 in the direction (the direction perpendicular to the first rotation shaft 112). Two arm portions 113 are attached to the first rotation shaft 112 so as to be symmetrically positioned in a direction perpendicular to the first rotation shaft 112. [ The first rotary shaft 112 and the arm portions 113 may be integrally formed or may be formed by joining separate members. Each of the arm portions 113 is curved from the lowermost portion 112a of the first rotary shaft 112 and extends upward monotonously as a result of which the lower arm portion 113 is generally U-shaped in cross section and convex downward. The first stirring jig 111 having the above configuration is also referred to as an anchor type in that it looks like an anchor.

4 is a sectional view showing another structure of the first stirring jig 111. Fig. Each of the arm portions 113 of the first stirring jig 111 may have a W-shaped cross section as a whole. That is, each of the arm portions 113 may have a shape that descends downward from the lowermost portion 112a of the first rotary shaft 112 toward the outer side in the radial direction and extends toward the uppermost portion 113a therefrom . The first stirring jig 111 is also an anchor type.

Figs. 5 to 7 are perspective views showing still another structure of the first stirring jig 111. Fig. 5, when the first stirring jig 111 is configured to have the arm portion 113 having a shape bent upwardly after extending from the lowermost portion of the first rotation shaft 112 outward in the rotation radial direction do. The first stirring jig 111 is also an anchor type. 6 and 7, the first stirring jig 111 is configured as an anchor paddle type, in which the area of the arm portion 113 is increased to improve the efficiency of stirring (webbing) .

The second stirring jig 121 shown in Fig. 3 has a second rotation shaft 122 and at least two stirring blades 123. [ In the present embodiment, two second stirring jigs 121 are provided in the stirring tank 101 and are located on opposite sides of the first stirring jig 111 with the first rotation shaft 112 therebetween.

The second rotation shaft 122 of the second stirring jig 121 extends in the vertical direction so as to pass through a space between the first rotation shaft 112 of the first stirring jig 111 and the arm portion 113. That is, the first rotation axis 112 and the second rotation axis 122 are parallel to each other. The second rotation shaft 122 is connected to a driving source (for example, a motor) not shown, and is rotated by driving of the driving source. The rotation speed of the second rotation shaft 122 (= rotation speed of the second stirring jig 121) is appropriately adjusted, for example, between 200 and 2000 rpm, and rotates at a speed higher than that of the first rotation shaft 112.

At least two stirring blades 123 are attached to the second rotation shaft 122 so as to be arranged along the vertical direction. When the two stirring blades 123 are distinguished, the uppermost stirring blade is referred to as a first stirring blade 123a and the stirring blade located below one of the first stirring blades 123a is referred to as a second stirring blade 123b do.

Here, the length along the vertical direction from the lowermost portion to the uppermost portion 113a of the arm portion 113 of the first stirring jig 111 is referred to as L (mm). That is, the length L of the arm portion 113 extends from the position Q corresponding to the lowermost portion of the arm portion 113 (equivalent to the lowermost portion 112a of the first rotary shaft 112 in Fig. 3) To the position P. 4, since the arm portion 113 extends upward toward the uppermost portion 113a after bending to a position R lower than the lowermost portion 112a of the first rotary shaft 112, The length L of the arm portion 113 is a length along the vertical direction from the position R to the position P. [ The length L of the arm portion 113 is preferably 1/4 or more of the length (depth) in the vertical direction of the stirring tank 101, more preferably 1/3 or more, and further preferably 1/2 or more .

3 and 4, a position vertically downward (1/3) L from the uppermost portion 113a of the arm portion 113 of the first stirring jig 111 (equivalent to the position P) , And position A, respectively. In this embodiment, the first stirring vane 123a of the second stirring jig 121 includes the position A and is located above the position A, and by rotation about the second rotation shaft 122, And a stirring blade for generating a flow in the vertical direction. As the stirring blade, a paddle type shown in Fig. 8 or a propeller type stirring blade shown in Fig. 9 can be used.

The second stirring vane 123b of the second stirring jig 121 is located below the position A and rotates around the second rotation shaft 122 to rotate the first stirring vane 123a And a stirring blade for causing a flow of the resin vertically downwardly drawn in the direction perpendicular to the second rotation shaft 122. [ The stirring blade is composed of a turbine-type stirring blade shown in Fig. 10 or a disk-type (dissolution type) stirring blade shown in Fig.

In the stirring and dispensing step, the dope composition is charged into the stirring tank 101 of the stirring apparatus 100 having the above-described configuration. The dope composition includes a resin, a solvent and an additive. Here, as the resin, a pellet-shaped resin such as an acrylic resin, a cycloolefin resin, or a polyarylate resin is used. As the solvent, methylene chloride, chloroform or the like is used. As the additive, fine particles (matting agent), plasticizer and the like are used. Since the specific gravity of the pellet-shaped resin is smaller than the specific gravity of the solvent (that is, since the resin is lighter than the solvent), even if a part of the resin is dissolved in the solvent initially, .

When the resin and the solvent are stirred by rotating the first stirring jig 111 and the second stirring jig 121 respectively, the first stirring wing 123a of the second stirring jig 121 rotates, The resin flows in the vertical direction (vertical direction in Fig. 3), that is, the resin flows downward from the upper side. By the rotation of the second stirring vane 123b, the flow of the resin vertically downwardly drawn by the first stirring vane 123a in the direction perpendicular to the second rotation axis 122, that is, A flow in the horizontal direction (left-right direction in Fig. 3) occurs. At this time, since the arm portion 113 of the first stirring jig 111 is rotated around the first rotation shaft 112, the resin and the solvent flowing in the horizontal direction by the second stirring vane 123b are transferred to the front Direction (the depth direction in Fig. 3).

The mixing ratio of the resin in the stirring tank 101 with the stirring of the first stirring blade 123a and the stirring of the second stirring blade 123b and the arm portion 113 (horizontal direction and shearing direction) And the solvent are uniformly and efficiently stirred to reduce stirring irregularity. Thereby, since the viscosity of the dope prepared by stirring is stabilized, the film thickness irregularity can be reduced when the optical film is formed using the dope. In addition, since the resin can be uniformly stirred in the stirring tank 101, it is difficult for the resin to aggregate in the stirring tank 101 and to cause aggregation (unmelted) It is possible to reduce the occurrence of spots on the spot caused by the defects.

Further, if the dope viscosity is unstable, adjustment of the doped viscosity (film thickness adjustment) becomes necessary in order to reduce unevenness in the film thickness, and the productivity of the optical film deteriorates as the adjustment time is required. However, in the present embodiment, since the dope viscosity is stabilized by the uniform stirring, the productivity of the optical film can be prevented from lowering.

When the specific gravity of the resin is represented by A, the specific gravity of the solvent is represented by B, and the specific gravity difference BA is represented by DELTA> 0.1, a resin is liable to be generated on the liquid surface of the solvent due to the specific gravity difference, Loses. However, in the present embodiment, since stirring unevenness can be reduced and the stirring tank 101 can be uniformly stirred as described above, even if the condition of?> 0.1, the generated mass is reduced by stirring, The occurrence of unheated seawater can be suppressed. As a result, in the formed optical film, foreign objects due to the unheated product can be reduced. If the specific gravity difference between the solvent and the resin is too large, the resin may not flow downward under the solvent even by stirring in the up and down direction, which may reduce the effect of reducing stirring irregularity. Therefore,? Is preferably less than 0.5. That is, the stirring method of the present embodiment is said to be particularly effective when the optical film is formed by preparing a dope by selecting a resin and a solvent that satisfy 0.1 <? <0.5.

Incidentally, the specific gravity of the acrylic resin, polymethyl methacrylate (PMMA) is 1.17, the specific gravity of the cycloolefin resin is 1.01, and the specific gravity of the polyarylate resin is 1.21. The specific gravity of methylene chloride was 1.32 and the specific gravity of chloroform was 1.48. Therefore, since any of the above resins satisfies 0.1 < DELTA < 0.5 between any of the above-mentioned solvents, the dope is produced by using the resin and the solvent in the method of this embodiment to form the optical film, , It is possible to reduce unevenness in film thickness due to agitation irregularity and generation of foreign objects. A more preferable range of the specific gravity difference? May be 0.1 <? <0.31 from the minimum value and the maximum value of the specific gravity difference in the combination of the resins and the respective solvents.

In addition, in the configuration in which two stirring blades for generating the upstream and downstream are used as in the conventional stirring apparatus, the force of the resin flowing from the upper side to the lower side is increased so that the resin is injected upwardly from below by the reaction at the bottom of the stirring tank The resin may adhere to the ceiling surface (lid portion) of the stirring tank. In this respect, in the present embodiment, since the stirring blades (first stirring blades 123a) for generating the upstream and downstream and the stirring blades (second stirring blades 123b) for generating the horizontal flow are used, The resin and the solvent can be uniformly stirred in the stirring tank 101. In addition, Therefore, the resin is hardly attached to the ceiling surface 101b of the stirring tank 101.

In the present embodiment, the first stirring vane 123a located at the uppermost position among the plurality of stirring vanes of the second stirring jig 121 includes the position A and is located above the second stirring vane 123a, The second stirring blade 123b and the arm portion 113 of the first stirring jig 111 are rotated by the rotation of the first stirring blade 123a so that the resin And the drawn resin and solvent can be surely stirred in the horizontal direction and the front end direction by the rotation of the second stirring vane 123b and the rotation of the arm portion 113. [

Since the first stirring blade 123a located at the uppermost position among the plurality of stirring blades of the second stirring jig 121 is a paddle type or propeller type stirring blade, the rotation of the first stirring blade 123a It is possible to reliably generate a flow in the vertical direction into the stirring tank 101, in particular, a flow of resin from the upper side to the lower side. On the other hand, since the second stirring vane 123b located below the first stirring vane 123a is a turbine or disc type stirring vane, the rotation of the second stirring vane 123b causes the horizontal direction resin It is possible to reliably generate the flow of the gas.

Since the first stirring jig 111 is composed of an anchor or anchor paddle type stirring vane (bottom blade), a space is formed between the first rotating shaft 112 and the arm portion 113. Therefore, as in the present embodiment, the second stirring jig 121 can be positioned in a part of the space. It is also possible to realize a configuration in which the resin and the solvent in the stirring tank 101 are uniformly stirred by the rotation of the first stirring jig 111 and the rotation of the second stirring jig 121. [

12 is a cross-sectional view showing another structure of the second stirring jig 121. As shown in Fig. The second stirring jig 121 may further include a third stirring vane 123c in addition to the first stirring vane 123a and the second stirring vane 123b. The third stirring vane 123c is located under one of the second stirring vanes 123b and is provided with a turbine type as shown in Fig. 10 or a disk-shaped stirring vane as shown in Fig. 11 like the second stirring vane 123b. .

The second stirring jig 121 has three stirring blades (the first stirring blade 123a, the second stirring blade 123b and the third stirring blade 123c) The second stirring vane 123b and the third stirring vane 123c are turbine or disk type stirring vanes so that the resin that has been drawn downward by the rotation of the first stirring vane 123a, (Depth direction) in the stirring tank 101 by the rotation of the first stirring blade 123b and the third stirring blade 123c and the resin and the solvent are supplied to the arm portion 113, It is possible to stir in a shear direction in a wide range in the vertical direction. That is, the rotation of the third stirring vane 123c generates a flow of resin in the horizontal direction even at a deeper position in the stirring tank 101, and the stirring in the shearing direction by the rotation of the arm portion 113 can be performed have. Thereby, the uniform stirring in the stirring tank 101 can be efficiently performed in a short time.

In the above description, the number of the arm portions 113 of the first stirring jig 111 is two, but the number of the arm portions 113 may be one or three or more. However, considering the efficiency of stirring, it is preferable that the number of the arm portions 113 is plural.

When the plurality of arm portions 113 are attached to the first rotation axis 112, the plurality of arm portions 113 are arranged in a plane perpendicular to the first rotation axis 112, It is preferable from the viewpoint of further reducing stirring irregularity in the stirring tank 101. [ For example, when the two arm portions 113 are attached to the first rotation axis 112 as shown in FIG. 3, it is preferable that the arm portions 113 are arranged at intervals of 180 degrees around the first rotation axis 112 Do. When the three arm portions 113 are attached to the first rotation shaft 112, it is preferable that the arm portions 113 are disposed at intervals of 120 degrees around the first rotation shaft 112. [ When the four arm portions 113 are attached to the first rotation shaft 112, it is preferable that the arm portions 113 are arranged at intervals of 90 degrees around the first rotation shaft 112. [

In the above description, the number of the second stirring jigs 121 in the stirring tank 101 is two, but the number of the second stirring jigs 121 may be one or three or more. However, considering the efficiency of stirring, it is preferable that the number of the second stirring jigs 121 is plural.

When the second stirring jig 121 is provided in a plurality of the jig 121, the second stirring jig 121 is arranged in the stirring tank 101 so as to face the first stirring jig 111, It is preferable to provide a plurality of the first rotary shaft 112 at the same angular intervals around the first rotary shaft 112 from the viewpoint of further reducing stirring irregularity in the stirring tank 101. [ For example, when the two second stirring jigs 121 are installed in the stirring tank 101 as shown in FIG. 3, the second stirring jigs 121 are arranged at intervals of 180 ° around the first rotation shaft 112 . When the three second stirring jigs 121 are provided in the stirring tank 101, each of the second stirring jigs 121 is preferably arranged at an interval of 120 degrees around the first rotating shaft 112 . When the four second stirring jigs 121 are provided in the stirring tank 101, it is preferable that the second stirring jigs 121 are arranged at intervals of 90 degrees around the first rotation shaft 112 . The number of the second stirring jigs 121 and the number of the arm portions 113 of the first stirring jig 111 may be the same or different.

〔Suzy〕

In the present embodiment, any of acrylic resin, cycloolefin resin, and polyarylate resin may be used as the resin used for producing the optical film, that is, the resin that is put into the stirring tank 101 and stirred and mixed with the solvent.

&Lt; Acrylic resin &

As the (meth) acrylic resin, the Tg (glass transition temperature) is preferably 115 ° C or more, more preferably 120 ° C or more, further preferably 125 ° C or more, particularly preferably 130 ° C or more. When the Tg is 115 占 폚 or more, the durability of the optical film is improved. The upper limit value of the Tg of the (meth) acrylic resin is not particularly limited, but is preferably 170 占 폚 or less from the viewpoint of moldability.

As the (meth) acrylic resin, any suitable (meth) acrylic resin may be employed as long as the effect of the present embodiment is not impaired. Examples thereof include poly (meth) acrylate esters such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylate ester copolymer, methyl methacrylate- (Meth) acrylic acid copolymer, a methyl methacrylate-styrene copolymer (MS resin, etc.), a polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate - (meth) acrylate norbornyl copolymer). Preferably, poly (meth) acrylate C1-6 alkyl such as poly (meth) acrylate is exemplified. More preferred is a methyl methacrylate resin having methyl methacrylate as a main component (50 to 100 mass%, preferably 70 to 100 mass%). As such, the acrylic resin includes a copolymer of an acrylic resin and another resin (compound) in addition to the acrylic resin itself.

Specific examples of the (meth) acrylic resin include acrylate VH and acrylate VRL20A, dianal BR52, BR80, BR83, BR85 and BR88 (manufactured by Mitsubishi Rayon Co., Ltd.) and KT75 (manufactured by Denki Kagaku Kogyo Co., (Meth) acrylic resin having a ring structure in the molecule described in Delpet 60N, 80N (manufactured by Asahi Kasei Chemicals Co., Ltd.) and JP-A No. 2004-70296, an intramolecular crosslinking or intramolecular cyclization And high Tg (meth) acrylic resin systems obtained by the reaction.

As the (meth) acrylic resin, it is also preferable to use a (meth) acrylic resin having a lactone ring structure. Examples of the (meth) acrylic resin having a lactone ring structure are disclosed in Japanese Patent Application Laid-Open Nos. 2000-230016, 2001-151814, 2002-120326, 2002-254544 And Japanese Patent Application Laid-Open No. 2005-146084.

As the (meth) acrylic resin, an acrylic resin having a structural unit of an unsaturated carboxylic acid alkyl ester and a structural unit of a glutaric acid anhydride can be used. As the acrylic resin, there can be mentioned, for example, Japanese Patent Application Laid-Open Nos. 2004-70290, 2004-70296, 2004-163924, 2004-292812, 2005 -314534, 2006-131898, 2006-206881, 2006-265532, 2006-283013, 2006, 2006 -299005, 2006-335902, and the like.

As the (meth) acrylic resin, a thermoplastic resin having a glutarimide unit, a (meth) acrylate unit, and an aromatic vinyl unit can be used. Examples of the thermoplastic resin include those described in JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328329, JP-A-2006-328334, JP- -337491, JP-A-2006-337492, JP-A-2006-337493, JP-A-2006-337569, etc.

<Cycloolefin Resin>

Examples of the cycloolefin resin (cycloolefin polymer) include a polymer or copolymer of a monomer having the structure represented by the following formula (S).

Wherein R ¹ to R ⁴ each independently represent a hydrogen atom, a hydrocarbon group, a halogen atom, a hydroxy group, a carboxyl group, an acyloxy group, an aryloxycarbonyl group, an alkoxycarbonyl group, an alkoxy group, a cyano group, A silyl group or a hydrocarbon group substituted with a polar group (i.e., a halogen atom, a hydroxy group, an acyloxy group, an aryloxycarbonyl group, an alkoxycarbonyl group, an alkoxy group, a cyano group, an amide group, an imide group or a silyl group).

Provided that at least two of R ¹ to R ⁴ may combine with each other to form an unsaturated bond, a monocyclic or polycyclic ring, and the monocyclic or polycyclic ring may have a double bond or may form an aromatic ring. R ¹ and R ² , or R ³ and R ⁴ , and may form an alkylidene group. p and m are an integer of 0 or more.

The hydrocarbon group represented by R ¹ and R ^{3 in} the general formula (S) is preferably a hydrocarbon group having 1 to 10 carbon atoms, more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 2 carbon atoms.

R ² and R ⁴ are each a hydrogen atom or a monovalent organic group, at least one of R ² and R ⁴ is preferably a polar group having a polarity other than a hydrogen atom and a hydrocarbon group, m is an integer of 0 to 3, p Is an integer of 0 to 3, more preferably m + p = 0 to 4, more preferably 0 to 2, particularly preferably m = 1 and p = 0.

Specific monomers having m = 1 and p = 0 are preferable in that the obtained cycloolefin resin has a high glass transition temperature and excellent mechanical strength. The glass transition temperature is a value obtained by a method based on JIS K 7121-2012 using DSC (Differential Scanning Colorimetry).

Examples of the polar group of the specific monomer include a carboxyl group, a hydroxy group, an alkoxycarbonyl group, an allyloxycarbonyl group, an amino group, an amide group and a cyano group. These polar groups may be bonded through a linking group such as a methylene group.

Further, a hydrocarbon group in which a divalent organic group having a polarity such as a carbonyl group, an ether group, a silyl ether group, a thioether group, or an imino group is bonded as a linking group may also be used as the polar group.

Among them, a carboxy group, a hydroxy group, an alkoxycarbonyl group or an allyloxycarbonyl group is preferable, and an alkoxycarbonyl group or an allyloxycarbonyl group is particularly preferable.

Further, a monomer in which at least one of R ² and R ⁴ is a polar group represented by the formula - (CH ₂ ) _n COOR is a monomer in which the cycloolefin resin obtained has a high glass transition temperature, low hygroscopicity, .

In the formula according to the specific polar group, R is a hydrocarbon group having 1 to 12 carbon atoms, more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 2 carbon atoms, preferably an alkyl group.

Specific examples of the copolymerizable monomers include cycloolefin resins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene and dicyclopentadiene.

The number of carbon atoms of the cycloolefin is preferably from 4 to 20, more preferably from 5 to 12.

In the present embodiment, the cycloolefin resin may be used singly or in combination of two or more.

The preferred molecular weight of the cycloolefin resin, and an intrinsic viscosity [η] _inh 0.2 to 5㎤ / g, more preferably from 0.3 to 3㎤ / g, particularly preferably 0.4 to 1.5㎤ / g, measured by gel permeation chromatography ( The number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC) is 8000 to 100000, more preferably 10000 to 80000, particularly preferably 12000 to 50000, a weight average molecular weight (Mw) Preferably 30,000 to 250,000, and particularly preferably 40,000 to 200,000.

When the intrinsic viscosity [?] _Inh , the number average molecular weight and the weight average molecular weight are within the above ranges, the heat resistance, water resistance, chemical resistance, mechanical properties and molding processability of the cycloolefin resin are improved.

The glass transition temperature (Tg) of the cycloolefin resin is usually 110 占 폚 or higher, preferably 110 to 350 占 폚, more preferably 120 to 250 占 폚, particularly preferably 120 to 220 占 폚. The Tg of 110 DEG C or higher is preferable because it is hard to cause deformation by use under high temperature conditions or secondary processing such as coating or printing.

On the other hand, by setting the Tg to 350 占 폚 or less, it is possible to prevent the molding process from being difficult and reduce the possibility that the resin is deteriorated by heat during molding.

The cycloolefin resin may contain, for example, a specific hydrocarbon-based resin described in JP-A-9-221577 and JP-A-10-287732, or a specific hydrocarbon- It may contain a known thermoplastic resin, a thermoplastic elastomer, a rubbery polymer, an organic fine particle, an inorganic fine particle and the like and may contain additives such as a specific wavelength dispersant, a sugar ester compound, an antioxidant, a peel promoter, rubber particles, a plasticizer, .

As the cycloolefin resin, commercially available products can be preferably used. Examples of commercially available products are commercially available from JSR Corporation under the trade names ARTON (registered trademark) G, ATON F, ATON R, and ATON RX. They are also commercially available under the trade names ZEONOR (registered trademark) ZF14, ZF16, ZEONEX (registered trademark) 250 or Zeonex 280 from Nippon Zeon Co., Ltd. These can be used.

<Polyarylate resin>

The polyarylate resin includes at least an aromatic dialcohol component unit and an aromatic dicarboxylic acid component unit.

(Aromatic dialcohol component unit)

The aromatic dialcohol for obtaining an aromatic dialcohol component unit is preferably a bisphenol represented by the following formula (1), more preferably a bisphenol represented by the following formula (1 ').

L in formulas (1) and (1 ') is a divalent organic group. The divalent organic group is preferably a single bond, an alkylene group, -S-, -SO-, -SO ₂ -, -O-, -CO- or -CR ₁ R ₂ - (R ₁ and R ₂ are bonded to each other To form an aliphatic or aromatic ring.

The alkylene group is preferably an alkylene group having 1 to 10 carbon atoms, and examples thereof include a methylene group, an ethylene group, and an isopropylidene group. The alkylene group may further have a substituent such as a halogen atom or an aryl group.

R ₁ and R ₂ of -CR ₁ R ₂ - are bonded to each other to form an aliphatic or aromatic ring. The aliphatic ring is preferably an aliphatic hydrocarbon ring having 5 to 20 carbon atoms, and is preferably a cyclohexane ring which may have a substituent. The aromatic ring is an aromatic hydrocarbon ring having 6 to 20 carbon atoms, and is preferably a fluorene ring which may have a substituent. Examples of -CR ₁ R ₂ - forming a cyclohexane ring which may have a substituent include cyclohexane-1,1-diyl group, 3,3,5-trimethylcyclohexane-1,1-diyl group and the like do. Examples of -CR ₁ R ₂ - which form a fluorene ring which may have a ring include a fluorenediyl group represented by the following formula.

R in formulas (1) and (1 ') may independently be an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. n is independently an integer of 0 to 4, preferably an integer of 0 to 3.

Examples of bisphenols in which L is an alkylene group include 1,1-bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) Hydroxyphenyl) methane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) methane, 2,2- (4-hydroxyphenyl) propane (BPA), 2,2-bis (3-methyl-4-hydroxyphenyl) propane (BPC), 2,2- ) Propane (TMBPA). Among them, 2,2-bis (4-hydroxyphenyl) propane (BPA), 2,2-bis (3-methyl-4-hydroxyphenyl) propane (BPC) -Dimethyl-4-hydroxyphenyl) propane (TMBPA).

Examples of bisphenols wherein L is -S-, -SO- or -SO ₂ - include bis (4-hydroxyphenyl) sulfone, bis (2-hydroxyphenyl) sulfone, bis (3,5-diethyl-4-hydroxyphenyl) sulfone, bis (3-methyl-4-hydroxyphenyl) sulfone, bis (3,5-dimethyl-4-hydroxyphenyl) sulfide, bis (3,5-diethyl-4-hydroxyphenyl) sulfide, bis , Bis (3-methyl-4-hydroxyphenyl) sulfide, bis (3-ethyl-4-hydroxyphenyl) sulfide and 2,4-dihydroxydiphenyl sulfone. Examples of bisphenols in which L is -O- include 4,4'-dihydroxydiphenyl ether. Examples of bisphenols in which L is -CO- include 4,4'-dihydroxydiphenyl ketone.

Examples of bisphenols in which L is -CR ₁ R ₂ - and R ₁ and R ₂ are bonded to each other to form an aliphatic ring include 1,1-bis (4-hydroxyphenyl) cyclohexane (BPZ) And bisphenols having a cyclohexane skeleton such as 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (BPTMC).

Examples of bisphenols in which L is -CR ₁ R ₂ - and R ₁ and R ₂ are bonded to each other to form an aromatic ring include 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene BCF), and 9,9-bis (3,5-dimethyl-4-hydroxyphenyl) fluorene (BXF).

The aromatic dialcohol component constituting the polyarylate may be one kind or two or more kinds.

Among them, from the viewpoint of enhancing the solubility of the resin in a solvent or enhancing the adhesiveness of the film with the metal, it is preferable to use, for example, a compound containing a sulfur atom (-S-, -SO- or -SO ₂ -) in the main chain Bisphenols are preferred. From the viewpoint of enhancing heat resistance of the film, for example, bisphenols containing a sulfur atom or bisphenols having a cycloalkylene skeleton in the main chain are preferable. From the viewpoint of reducing the birefringence of the film or increasing the abrasion resistance, bisphenols having a fluorene skeleton are preferred.

Bisphenols having a cyclohexane skeleton or bisphenols having a fluorene skeleton are preferably used in combination with bisphenols containing an isopropylidene group. In this case, the content ratio of the bisphenols having a cyclohexane skeleton or the bisphenols having a fluorene skeleton and the bisphenols containing an isopropylidene group is preferably 10/90 to 90/10 (molar ratio), preferably 20/80 To 80/20 (molar ratio).

The polyarylate may further contain an aromatic polyhydric alcohol component unit other than the aromatic dialcohol component within a range that does not impair the effect of the present embodiment. Examples of the aromatic polyhydric alcohol component include the compounds described in paragraph [0015] of Japanese Patent No. 4551503. Specific examples thereof include tris (4-hydroxyphenyl) methane, 4,4 '- [1- [4- [1- (4- hydroxyphenyl) (4-hydroxyphenyl) methyl] -2-methoxyphenol, tris (3-methyl-4-hydroxyphenyl) methane, and the like . The content ratio of these aromatic polyhydric alcohol component units may be appropriately set in accordance with required properties, but may be set to, for example, not more than 5 mol% with respect to the total amount of the aromatic dialcohol component units and other aromatic polyhydric alcohol component units have.

(Aromatic dicarboxylic acid component unit)

The aromatic dicarboxylic acid constituting the aromatic dicarboxylic acid component unit may be terephthalic acid, isophthalic acid or a mixture thereof.

A mixture of terephthalic acid and isophthalic acid is preferable from the standpoint of enhancing the mechanical properties of the film and the like. The content ratio of terephthalic acid and isophthalic acid is preferably terephthalic acid / isophthalic acid = 90/10 to 10/90 (molar ratio), more preferably 70/30 to 30/70, still more preferably 50/50. If the content of terephthalic acid is within the above range, polyarylate having a sufficient degree of polymerization tends to be obtained, and a film having sufficient mechanical properties tends to be obtained.

The polyarylate may further contain an aromatic dicarboxylic acid component unit other than terephthalic acid and isophthalic acid within a range that does not impair the effect of the present embodiment. Examples of such aromatic dicarboxylic acid components include orthophthalic acid, 2,6-naphthalene dicarboxylic acid, diphenic acid, 4,4'-dicarboxy diphenyl ether, bis (p-carboxyphenyl) , 4'-dicarboxyphenylsulfone, and the like. The content ratio of the aromatic dicarboxylic acid component units other than terephthalic acid and isophthalic acid can be appropriately set according to the required properties. However, the content of the aromatic dicarboxylic acid component units other than terephthalic acid component, isophthalic acid component unit, For example, 5 mol% or less.

(Glass transition temperature)

The glass transition temperature of the polyarylate is preferably 260 占 폚 or more and 350 占 폚 or less, more preferably 265 占 폚 or more and less than 300 占 폚, and still more preferably 270 占 폚 or more and less than 300 占 폚.

The glass transition temperature of the polyarylate can be measured in accordance with JIS K7121 (1987). Specifically, DSC6220 manufactured by Seiko Instruments Inc. can be used as a measuring device, and measurement can be performed under the conditions of 10 mg of a polyarylate sample and a temperature raising rate of 20 캜 / min.

The glass transition temperature of the polyarylate can be adjusted by the kind of the aromatic dialcohol component constituting the polyarylate. In order to increase the glass transition temperature, it is preferable to include, for example, an aromatic dialcohol component unit "a unit derived from a bisphenol containing a sulfur atom in the main chain".

(Intrinsic viscosity)

The intrinsic viscosity of the polyarylate is preferably 0.3 to 1.0 dl / g, more preferably 0.4 to 0.9 dl / g, still more preferably 0.45 to 0.8 dl / g, even more preferably 0.5 to 0.7 dl / g desirable. If the intrinsic viscosity of the polyarylate is 0.3 dl / g or more, the molecular weight of the resin composition tends to be more than a certain level, and a film having sufficient mechanical properties and heat resistance tends to be obtained. If the intrinsic viscosity of the polyarylate is 1.0 dl / g or less, excess viscosity of the solution at the time of film formation can be suppressed.

The intrinsic viscosity can be measured in accordance with ISO1628-1. Specifically, a solution prepared by dissolving a polyarylate sample at a concentration of 1 g / dl in 1,1,2,2-tetrachloroethane is prepared. The intrinsic viscosity at 25 ° C is measured in this solution using a Ubbelohde type viscosity tube.

The polyarylate may be produced by a known method, preferably an interfacial polymerization method (WM) in which an aromatic dicarboxylic acid halide dissolved in an organic solvent not compatible with water is mixed with an aromatic dialcohol dissolved in an aqueous alkali solution EARECKSON, J. Poly. Sci., XL 399, 1959, Japanese Patent Publication No. 40-1959).

The content of the polyarylate may be 50% by mass or more, preferably 60% by mass or more, and more preferably 80% by mass or more, based on the entire polyarylate film.

〔menstruum〕

Examples of the solvent used in the production of the optical film, that is, the solvent for dissolving the above-mentioned resin in the stirring tank of the stirring device in this embodiment include dichloromethane (methylene chloride, methylene chloride), chloroform, ethanol, Butanol, isopropanol, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, N, N-dimethylacetamide, N, N-diethylacetamide, N, , N-diethylformamide, N-methylcaprolactam, hexamethylphosphoramide, tetramethylene sulfone, dimethyl sulfoxide, m-cresol, phenol, p- chlorophenol, But are not limited to, tetrahydrofuran (THF), tetrahydrofuran (THF), tetrahydrofuran, tetrahydrofuran, dioxane, ) May be used, and these may be used singly or in combination of two or more. In addition to these solvents, a poor solvent such as hexane, heptane, benzene, toluene, xylene, chlorobenzene or o-dichlorobenzene may be used.

〔additive〕

As the additive to be contained in the dope of the present embodiment, fine particles, plasticizer, ultraviolet absorber, antioxidant, sugar ester compound, retardation adjuster, light stabilizer, antistatic agent, exfoliating agent and thickener may be used. Only the main additives will be described below.

&Lt; Particles (Mat) >

The optical film of the present embodiment preferably contains a matting agent in order to impart unevenness to the surface of the film at the time of film formation, ensure slidability, and achieve a stable winding shape. By containing the matting agent, scratches or deterioration in conveying property can be suppressed when the produced optical film is handled.

Examples of the matting agent include fine particles of an inorganic compound and fine particles of a resin. Examples of the fine particles of the inorganic compound 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 . It is preferable that the fine particles include silicon because the turbidity is lowered, 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 within a range of particle diameters of 0.05 to 0.3 탆. If the particles have an average particle diameter within a range of 80 to 400 nm, they are preferably contained as primary particles without aggregation.

The content of these fine particles in the optical film is preferably in the range of 0.01 to 3.0 mass%, more preferably in the range of 0.01 to 2.0 mass%.

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., Ltd.) have.

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 these can be used.

Examples of the fine particles of the resin 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, they are commercially available under the trade names of Tospearl 103, 105, 108, 120, 145, 3120 and 240 (manufactured by Toshiba Silicone Co., Ltd.).

Of these, Aerosil 200V, Aerosil R972V and Aerosil R812 are particularly preferably used since they have a large effect of lowering the friction coefficient while keeping the haze of the optical film low.

<Plasticizer>

As the plasticizer to be added to the optical film, a polyester resin can be used. The polyester resin is obtained by polymerizing a dicarboxylic acid and a diol, and 70% or more of the dicarboxylic acid constituent unit (constituent unit derived from the dicarboxylic acid) is derived from an aromatic dicarboxylic acid, More than 70% of units (constitutional units derived from diol) are derived from aliphatic diols.

The proportion of the structural unit derived from an aromatic dicarboxylic acid is 70% or more, preferably 80% or more, and more preferably 90% or more. The proportion of the constitutional unit derived from an aliphatic diol is 70% or more, preferably 80% or more, and more preferably 90% or more. Two or more kinds of polyester resins may be used in combination.

Examples of the aromatic dicarboxylic acid include naphthalene dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid and 2,7-naphthalene dicarboxylic acid, 4 , 4'-biphenyldicarboxylic acid, 3,4'-biphenyldicarboxylic acid and the like, and ester-forming derivatives thereof.

As the polyester resin, aliphatic dicarboxylic acids such as adipic acid, azelaic acid and sebacic acid, and monocarboxylic acids such as benzoic acid, propionic acid and butyric acid may be used as long as the object of the present invention is not impaired.

Examples of the aliphatic diol include ethylene glycol, 1,3-propylene diol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, and the like, and ester-forming derivatives thereof.

To the polyester resin, monohydric alcohols such as butyl alcohol, hexyl alcohol and octyl alcohol, and polyhydric alcohols such as trimethylol propane, glycerin and pentaerythritol may be used as long as the object of the present invention is not impaired.

For the production of the polyester resin, known methods such as a direct esterification method and an ester exchange method can be applied. Examples of the polycondensation catalyst to be used in the production of the polyester resin include known antimony compounds such as antimony trioxide and antimony pentoxide, germanium compounds such as germanium oxide, titanium compounds such as titanium acetate and aluminum compounds such as aluminum chloride But are not limited to these.

Preferable examples of the polyester resin include polyethylene terephthalate resin, polyethylene terephthalate-isophthalate copolymer resin, polyethylene-1,4-cyclohexanedimethylene-terephthalate copolymer resin, polyethylene-2,6-naphthalene dicarboxylate resin, polyethylene- 2,6-naphthalenedicarboxylate-terephthalate copolymer resin, polyethylene-terephthalate-4,4'-biphenyldicarboxylate resin, poly-1,3-propylene-terephthalate resin, polybutylene terephthalate Resin, polybutylene-2,6-naphthalenedicarboxylate resin, and the like.

Examples of the more preferable polyester resin include polyethylene terephthalate resin, polyethylene terephthalate-isophthalate copolymer resin, polyethylene-1,4-cyclohexanedimethylene-terephthalate copolymer resin, polybutylene terephthalate resin, and polyethylene- And naphthalene dicarboxylate resins.

The intrinsic viscosity (value measured at 25 占 폚 in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane = 60/40 mass ratio) of the polyester resin is preferably in the range of 0.7 to 2.0 cm3 / g, More preferably 0.8 to 1.5 cm 3 / g. When the intrinsic viscosity is 0.7 cm 3 / g or more, the molecular weight of the polyester resin is sufficiently high. Therefore, the molded article containing the polyester resin composition obtained by using the polyester resin composition has mechanical properties required as a molded product and good transparency. When the intrinsic viscosity is 2.0 cm 3 / g or less, moldability is improved. As other plasticizers, the compounds described in the general formulas (PEI) and (PEII) in paragraphs [0056] to [0080] of Japanese Patent Laid-Open Publication No. 2013-97279 may be used.

[Examples]

Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples.

<Preparation of stirring apparatuses A to I>

First, stirring apparatuses A to I, which satisfied the conditions shown in Table 1, were prepared. The width of the stirring tank 101 (diameter of the bottom surface 101a) is 2100 mm and the height of the liquid surface when the resin and the solvent are put into the stirring tank 101 The height from the bottom surface 101a of the top portion 113a of the arm portion 113 is 2000 mm and the height of the arm portion 113 is 500 mm above the top portion 113a of the arm portion 113 of the stirring jig 111, 113 are 1800 mm and the distance between the uppermost portions 113a of the two arm portions 113 (the distance in the direction perpendicular to the first rotary shaft 112) is 2050 mm, and the length L of the first rotary shaft 112, And the second rotating shaft 122 is 750 mm.

Further, the configurations of the stirring devices A to I are schematically shown in Figs. 13 to 18. Fig. In these figures, the position of the central portion in the height direction of the arm portion 113 of the first stirring jig 111 is shown by the position B.

&Lt; Production of optical film 1 >

(Synthesis of Acrylic Resin 1 (Copolymer A1)

As a monomer, 2,2-bis (4 (meth) acrylic acid) was added to a mixed solution of 93.6 parts by mass (90 mol%) of styrene, 7.2 parts by mass (10% by mole) of acrylic acid, 29.4 parts by mass of ethylbenzene and 3.3 parts by mass of 2-ethylhexanol , 4-di-tert-butyl peroxide) propane was added in an amount of 0.04 parts by mass, and the polymerization solution was continuously introduced into a polymerization apparatus having a 5.0 L complete mixed type reactor at 1.67 L / hr. At this time, the temperature of the fully mixed reactor was adjusted to 135 캜. Subsequently, the polymer solution continuously discharged from the polymerization reactor was fed to a deep groove type screw extruder reduced in pressure to 2.7 to 4.0 kPa, and volatile components were removed to obtain a pellet-shaped copolymer A1. The proportion of the monomer units in the copolymer A1 was 90 mol% of the styrene monomer, 10 mol% of the acrylic acid monomer, and the weight average molecular weight was 300,000.

The following components were stirred using the stirring apparatus A prepared above and fully dissolved while heating to prepare Dope 1. At this time, the stirring speed (rotation speed) of the first stirring jig of the stirring device A was 50 rpm, and the stirring speed (rotation speed) of the second stirring jig was 500 rpm. The agitation time in the stirring apparatus A was 5 hours.

(Composition of Dope 1)

Copolymer A1 (styrene: 90 mol%, acrylic acid: 10 mol%, weight average molecular weight: 300,000)

100 parts by mass

Matte R812 (manufactured by Nippon Aerosil Co., Ltd., silica particles, average particle diameter 8 nm)

0.30 parts by mass

Methylene chloride 150 parts by mass

ethanol 5 parts by mass

The prepared dope 1 was uniformly plied with a stainless steel band support at a temperature of 22 캜 and a width of 2 m by using a belt softener. The solvent was evaporated by a stainless steel band support until the amount of the residual solvent became 50%, and the obtained film was peeled off from the stainless steel band support at a peeling tension of 162 N / m.

Next, the peeled film material was dried at a drying temperature of 135 캜 while being stretched by 1.25 times in the transverse direction (TD direction) by stretching the solvent at 35 캜 by tenter stretching. The amount of the residual solvent when the stretching by the stretching by the zone was started was 20.0%, and the amount of the residual solvent when the stretching by the tenter was started was 8.0%.

After stretching with a tenter, the film was subjected to a relaxation treatment at 130 占 폚 for 5 minutes, and the drying was then carried out while conveying the drying zone at 120 占 폚 and 140 占 폚 by a plurality of rollers. The resulting film was slit at a width of 1.5 m, knurled at both ends of the film by 10 mm in width and 5 탆 in height, and then wound around a core to prepare an optical film 1 as an acrylic film. The film thickness of the produced optical film 1 was 40 μm and the winding length was 4000 m.

&Lt; Production of optical films 2 to 6 >

Optical films 2 to 6 were respectively prepared in the same manner as in the production of optical film 1 except that the resin or the like was stirred using stirring devices B to F instead of stirring apparatus A to prepare dope.

&Lt; Production of optical film 7 >

(Synthesis of cycloolefin resin COP1)

As the cycloolefin resin, a cycloolefin resin COP1 synthesized as follows was prepared.

First, 50 g of 8-methoxycarbonyl-8-methyltetracyclo [4.4.0.12,5.17,10] -3-dodecene represented by the above structural formula, 2.3 g of 1-hexene as a molecular weight modifier and 100 g of toluene were charged And the mixture was heated to 80 ° C. To this was added 0.09 ml of a toluene solution of triethyl aluminum (0.6 mol / L) and 0.29 ml of a toluene solution (0.025 mol / L) of methanol-denatured WCl ₆ , and the mixture was reacted at 80 ° C for 3 hours to obtain a polymer. Then, the obtained ring-opening copolymer solution was placed in an autoclave, and 100 g of toluene was further added. The hydrogenation catalyst RuHCl (CO) [P (C ₆ H ₅ )] ₃ was added in an amount of 2500 ppm based on the amount of the monomer introduced, and the hydrogen gas pressure was adjusted to 9 to 10 MPa for 3 hours at 160 to 165 ° C. After completion of the reaction, a large amount of methanol solution was precipitated to obtain a hydrogenated product. The cycloolefin resin COP1, which is a hydrogenated product of the ring opening polymer, had a glass transition temperature (Tg) of 167 占 폚, a weight average molecular weight (Mw) of 13.5 占⁰⁴ and a molecular weight distribution (Mw / Mn) of 3.06.

(Preparation of fine particle dispersion)

12 parts by mass of fine particles (Aerosil R972V, manufactured by Nippon Aerosil Co., Ltd.) and 88 parts by mass of ethanol were mixed with a dissolver for 50 minutes with stirring, and then dispersed with mannitol-gaulin to prepare a fine particle dispersion.

Subsequently, 100 parts by mass of the fine particle dispersion was slowly added to dichloromethane (100 parts by mass) stirred in the stirring apparatus A. Further, dispersion was carried out with an attritor so that the particle diameter of the secondary particles became a predetermined size. The solution was filtered with Fine Mat NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle addition liquid.

(Preparation of main doping)

The main dope of the following composition was prepared. First, dichloromethane and ethanol were added to the stirring apparatus A. The cycloolefin resin COP1 and the particulate addition liquid were added to the stirring apparatus A containing dichloromethane while stirring. This was heated, and the resin was dissolved while stirring, and this was dissolved in Azumi Co., Ltd., manufactured by Azumi Co., Ltd. 244, and the main dope was prepared. The stirring conditions in the stirring apparatus A are the same as those in the production of the optical film 1.

<The composition of main dop>

Cycloolefin resin COP1 100 parts by mass

Methylene chloride 200 parts by mass

ethanol 10 parts by mass

The particulate additive liquid 10 parts by mass

(Film Formation of Optical Film)

The prepared dope 1 was uniformly plied with a stainless steel band support at a temperature of 22 캜 and a width of 2 m by using a belt softener. In the stainless steel band support, the solvent was evaporated until the residual solvent amount became 30%, and the obtained film was peeled off on a stainless steel band support at a peel tension of 162 N / m.

Next, the peeled film-like material was evaporated at 35 占 폚 and dried at a drying temperature of 160 占 폚 while being stretched by 1.25 times in the transverse direction (TD direction) by tenter stretching. The amount of the residual solvent when the stretching by the stretching by the zone was started was 10.0%, and the amount of the residual solvent when the stretching by the tenter was started was 5.0%.

After being stretched by a tenter, the sheet was subjected to a relaxation treatment at 160 DEG C for 5 minutes, and then the drying zone was conveyed by a plurality of rollers at a temperature of 120 DEG C to terminate the drying. The obtained film was slit with a width of 1.5 m, knurled at both ends of the film by 10 mm in width and 5 탆 in height, and then wound around a core to prepare an optical film 7 as a cycloolefin. The film thickness of the produced optical film 7 was 40 탆 and the winding length was 4000 m.

&Lt; Production of optical film 8 >

An optical film 8 was prepared in the same manner as in the production of the optical film 1 except that methylene chloride was replaced with methylene chloride in the same amount as chloroform and stirred to prepare a dope.

<Production of optical film 9>

An optical film 9 was produced in the same manner as in the production of the optical film 1, except that Dope 2 having the following composition containing acrylic resin 2 was used in place of Dope 1.

(Composition of Dope 2)

Acrylic resin 2 (Dianal BR85, manufactured by Mitsubishi Rayon Co., Ltd.)

100 parts by mass

Matte R812 (manufactured by Nippon Aerosil Co., Ltd., silica particles, average particle diameter 8 nm)

0.30 parts by mass

Methylene chloride 150 parts by mass

ethanol 5 parts by mass

&Lt; Fabrication of optical film 10 >

(Production of polyarylate)

After 2514 parts by weight of water was added to the reaction vessel, 22.7 parts by weight of sodium hydroxide, 35.6 parts by weight of 9,9-bis (3,5-dimethyl-4-hydroxyphenyl) fluorene (BCF) as an aromatic dialcohol component, 18.5 parts by weight of 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane (TMBPA) and 0.049 parts by weight of p-tert-butylphenol (PTBP) as a molecular weight regulator were dissolved to obtain 0.34 parts by weight of a polymerization catalyst Tributylbenzylammonium chloride) was added and stirred.

On the other hand, 26.8 parts by weight of an equimolar mixture of terephthalic acid chloride and isophthalic acid chloride as an aromatic dicarboxylic acid component was weighed and dissolved in 945 parts by weight of methylene chloride. The methylene chloride solution was added to the alkali aqueous solution prepared as described above with stirring to initiate polymerization. The polymerization reaction temperature was adjusted to be not less than 15 ° C and not more than 20 ° C. The polymerization was carried out for 2 hours. Thereafter, acetic acid was added to the system to terminate the polymerization reaction, and the organic phase and water phase were separated.

The obtained organic phase was washed with twice the amount of the organic phase ion-exchanged water every washing, and then the operation of separating the organic phase and water phase was repeated. The cleaning was completed when the electrical conductivity of the washing water became less than 50 占 / / cm. The organic phase after washing was charged into a hot water bath equipped with a homomixer at 50 DEG C to evaporate methylene chloride to obtain a powdery polymer. Further, dehydration and drying were carried out to obtain polyarylate.

14 parts by mass of the polyarylate prepared above and 100 parts by mass of methylene chloride were placed in an agitator A, and the temperature was gradually raised to 45 캜 while stirring to completely dissolve the mixture. The obtained solution was dispersed in a solution prepared by dissolving the obtained solution in an aqueous solution of azulic acid (manufactured by Azumi Co., Ltd.). 244 to obtain a polymer solution.

The resulting polymer solution was uniformly plied onto a stainless steel belt of a belt casting machine. A stainless steel belt having a length of 20 m was used. The surface temperature of the stainless steel belt was set at 35 DEG C, and the flexible film was allowed to air at 35 DEG C, the solvent was evaporated until the residual solvent amount became 38%, and the film was peeled off from the stainless steel belt to obtain a film.

The film-like material thus obtained was stretched 1.2 times at 170 DEG C in the MD direction using the difference in speed between rolls, and then stretched 1.2 times at 230 DEG C in the TD direction by a tenter.

The stretched film was dried in a dryer at 125 DEG C for 30 minutes while being conveyed by a plurality of rolls and knurled at both ends in the width direction of the film to a width of 15 mm and a height of 10 mu m to form a film An optical film 10 having a thickness of 40 탆 was obtained.

&Lt; Fabrication of optical films 11 to 13 >

Optical films 11 to 13 were respectively prepared in the same manner as in the production of optical film 1 except that the resin or the like was stirred using agitation apparatuses G to I in place of stirring apparatus A to prepare dope.

&Lt; Fabrication of optical film 14 >

An optical film 14 was prepared in the same manner as in the production of the optical film 1 except that methylene chloride was replaced with methylene chloride in the same amount as THF (tetrahydrofuran) instead of methylene chloride to prepare a dope.

<Evaluation>

(Evaluation of Film Thickness Unevenness)

For each of the optical films 1 to 14 prepared above, the film thickness (占 퐉) was measured using a micrometer at intervals of 10 mm in the width direction of the film, and the difference (占 퐉) between the maximum value and the minimum value of each film thickness And the film thickness was uneven. If the film thickness unevenness is 1.0 占 퐉 or less, there is no problem in actual use, and if it exceeds 1.0 占 퐉, there is a problem in practical use.

(Evaluation of foreign objects)

A sample (optical film produced) was placed between two polarizing plates arranged in an orthogonal state (Cross Nicol), light was radiated from the outside of one polarizing plate, and the outside of the other polarizing plate was irradiated with a transmission electron microscope 50 times , And the number of foreign objects (bright spots) visible at an area of 25 cm 2 was counted and converted into the number per 1 cm 2. Then, the observation was performed at 10 sites per sample, and the number of foreign objects was measured, and the average value was determined as the number of foreign objects. Based on the following evaluation criteria, the foreign object was evaluated.

"Evaluation standard"

◎ ... The number of foreign objects is less than 0.15 per 1 cm 2

○ ... The number of foreign objects is greater than 0.15 pieces per 1 cm 2, and not more than 0.20 pieces

△ ... The number of foreign matters is greater than 0.20 per 1 cm 2, and not more than 0.25

× ... The number of foreign objects is greater than 0.25 and less than 0.35 per 1 cm 2, but there is a problem in practical use

Xx ... The number of foreign objects is larger than 0.35 per 1 cm 2, and there is a considerable problem in practical use

Table 2 shows the results of evaluation of the resin, solvent, stirring apparatus, and evaluation used for the film formation of each optical film 1 to 14.

From Table 2, in the optical film 11, the film thickness unevenness and the evaluation of the foreign matter were poor. This is because the dope used for film formation of the optical film 11 is prepared by using the stirring device G, but in the stirring device G, as shown in Fig. 17, the first stirring blade 123a is lower than the position A vertically downwardly downward (1/3) L from the uppermost portion 113a of the arm portion 113 of the first stirring jig 111, the specific gravity is small, The resin floating above can not be drawn down efficiently by the first stirring vane 123a, and as a result, stirring irregularity occurs.

Also in the case of the optical film 12, unevenness of the film thickness and evaluation of foreign matter were poor. This is because the dope used for the film formation of the optical film 12 was prepared using the stirring device H, but in the stirring device H, as shown in Table 1, the first stirring blade 123a at the top of the second stirring jig 121 Shaped stirring blade that makes a flow in a direction perpendicular to the second rotation axis 122, the resin floating above the solvent also has a specific gravity smaller than that of the resin by the first stirring blade 123a It can not be efficiently drawn downward, and as a result, stirring irregularity occurs.

Also in the optical film 13, unevenness in film thickness and evaluation of foreign matter were poor. This is because the dope used for the film formation of the optical film 13 was prepared using the stirring apparatus I, but in the stirring apparatus I, as shown in Fig. 18, the stirring blade of the second stirring jig 121 was rotated by the first stirring blade And the resin drawn downward by the first stirring vane 123a can not be stirred in the front end direction between the arm portions 113. As a result, large irregularity in agitation has occurred I think.

Also in the optical film 14, unevenness in film thickness and evaluation of foreign matter were poor. This is presumably because the resin used in the film formation of the optical film 13 has a larger specific gravity than the solvent and is heavy, so that even when the resin is stirred in the stirring tank 101, the resin does not flow upward, and stirring irregularity occurs.

On the contrary, in the optical films 1 to 10, the film thickness unevenness and the evaluation of foreign matters were all good. This is because the dope used in the film formation of the optical films 1 to 10 was prepared by using any one of the stirring devices A to F. In these stirring devices, (1) the first stirring wing 123a of the second stirring jig 121 (Propeller type, paddle type) for generating a flow in the vertical direction of the resin, (2) the second stirring blade 123b is located at a position higher than the position A, (Disk type, turbine type) which is located below the position B and causes a flow in a direction perpendicular to the second rotation axis 122, so that uniform stirring in the stirring tank 101 I think it is possible. That is, by the above-described (1) and (2), the stirring in the vertical direction by the first stirring vane 123a and the stirring in the shearing direction by the second stirring vane 123b and the arm portion 113 Therefore, even if the specific gravity difference? Between the solvent and the resin is 0.1 <? &Lt; 0.5, it is considered that the resin and the solvent in the stirring tank 101 are uniformly and efficiently stirred to reduce stirring irregularity.

Particularly, in the stirring device F, since the second stirring jig 121 has three stirring blades and stirring is performed more efficiently, evaluation of the unevenness of the film thickness and the evaluation of the foreign matter are more favorable due to the reduction of stirring unevenness I think it is.

<Preparation of stirring apparatus J to L>

Next, stirring devices J to L satisfying the conditions shown in Table 3 were prepared. The stirring apparatus J has the same structure as the stirring apparatus A except that the number of arm portions of the first stirring jig of the stirring apparatus A is changed from two to one. The stirring apparatus K has the same configuration as the stirring apparatus A except that the number of arm portions of the first stirring jig of the stirring apparatus A is changed from two to three. At this time, the three arm portions are arranged at regular intervals of 120 DEG around the first rotation axis. The stirring apparatus L has the same structure as the stirring apparatus A except that the number of arm portions of the first stirring jig of the stirring apparatus A is changed from two to four. At this time, the four arm portions are arranged around the first rotation axis at regular intervals of 90 degrees.

&Lt; Production of optical films 15 to 17 >

Optical films 15 to 17 were respectively prepared in the same manner as in the production of optical film 1 except that the resin and the like were stirred using stirring apparatuses J to L instead of stirring apparatus A to prepare dope.

<Preparation of stirring apparatus M to O>

Next, stirring devices M to O satisfying the conditions shown in Table 4 were prepared. The stirring apparatus M has the same configuration as the stirring apparatus A except that the number of the second stirring jigs of the stirring apparatus A is changed from two to one. The stirring apparatus N has the same configuration as the stirring apparatus A except that the number of the second stirring jigs of the stirring apparatus A is changed from two to three. At this time, the three second stirring jigs are arranged around the second rotation axis at equal intervals of 120 DEG. The stirring apparatus O has the same structure as the stirring apparatus A except that the number of the second stirring jig of the stirring apparatus A is changed from two to four. At this time, the four second stirring jigs are arranged around the second rotation axis at regular intervals of 90 degrees.

&Lt; Fabrication of optical films 18 to 20 >

Optical films 18 to 20 were respectively prepared in the same manner as in the production of optical film 1 except that the resin or the like was stirred using agitation apparatuses M to O instead of stirring apparatus A to prepare dope.

The optical films 15 to 20 prepared above were evaluated for film thickness unevenness and foreign matters in the same manner as the optical film 1 and the like. Table 5 shows the results of the evaluation.

The stirrer J used in the film formation of the optical film 15 has a smaller number of arms than the stirrer A. Further, the stirring apparatus M used in the film formation of the optical film 18 has a smaller number of the second stirring jig than the stirring apparatus A. However, these stirring apparatuses J and M do not differ in that the conditions (1) and (2) are satisfied. Therefore, in the optical films 15 and 18, the film thickness unevenness and the evaluation of the foreign matters are lower than those of the optical film 1, but there is no problem in practical use, and the stirring apparatuses J and M also have the effect of reducing stirring irregularity .

Further, since the stirring devices K and L used in the film formation of the optical films 16 to 17 have a larger number of arms than the stirring device A, the stirring efficiency is further improved as compared with the stirring device A, stirring unevenness is further reduced, And the evaluation of foreign matter is considered to be better.

Further, since the stirring apparatuses N and O used in the film formation of the optical films 19 to 20 have a larger number of second stirring jigs than the stirring apparatus A, the stirring efficiency is further improved as compared with the stirring apparatus A, It is considered that the evaluation of the film thickness unevenness and the foreign matter becomes better.

〔supplement〕

Although the embodiment of the present invention has been described above, the scope of the present invention is not limited to this, but various modifications may be made without departing from the gist of the invention.

The manufacturing method of the optical film of the present embodiment described above can be expressed as follows.

1. A method for producing an optical film by solution casting film forming method,

A stirring and mixing step of stirring at least a resin and a solvent in a stirring tank to prepare a dope,

And a softening step of softening the dope prepared in the stirring and mixing step on a support,

The resin is any one of an acrylic resin, a cycloolefin resin, and a polyarylate resin,

The specific gravity of the resin is represented by A, the specific gravity of the solvent is represented by B, and the specific gravity difference (B-A)

0.1 <

Lt;

In the stirring tank, a first stirring jig and a second stirring jig are provided,

Wherein the first stirring jig includes a first rotating shaft located on a vertical axis passing through the center of the bottom surface of the stirring tank and a second rotating shaft located above the lowermost portion in the stirring tank from the lowermost portion of the first rotating shaft, And an arm portion extending from the rotation axis to a position spaced apart in the radial direction of rotation,

The second stirring jig includes the second rotation shaft extending in the vertical direction so as to pass through the space between the first rotation shaft and the arm portion and at least two stirring wings attached to the second rotation shaft so as to be arranged along the vertical direction Have,

A length of the arm portion of the first stirring jig is L and a stirring blade of the uppermost one of the at least two stirring blades of the second stirring jig and a stirring blade located below the one of the at least two stirring blades of the second stirring jig are respectively referred to as first When a stirring blade and a second stirring blade are used,

Wherein the first stirring vane includes a position vertically downwardly downward (1/3) L from the uppermost portion of the arm portion of the first stirring jig and is located above the first stirring vane, and is rotated by the rotation about the second rotation axis And a stirring blade for causing a flow of the resin in the vertical direction,

Wherein the second stirring blade is located below a position vertically downwardly downward by (1/3) L from the uppermost portion of the arm portion of the first stirring jig, and by rotation about the second rotation axis, And a stirring blade which generates a flow of the resin drawn vertically downward by the stirring blade in a direction perpendicular to the second rotation axis.

2. 0.1 <? <0.31

(2) The method for producing an optical film according to (1) above,

3. The process for producing an optical film according to 1 or 2, wherein the solvent comprises methylene chloride or chloroform.

4. The method for producing an optical film according to any one of 1 to 3 above, wherein the first stirring blade is a stirring blade of a paddle type or a propeller type.

5. The method for producing an optical film according to any one of 1 to 4, wherein the second stirring blade is a turbine-type or disk-type stirring blade.

6. The method for producing an optical film as described in any one of 1 to 5 above, wherein the first stirring jig is composed of an anchor type or an anchor paddle type stirring blades.

7. The second stirring jig further has a third stirring blade located under one of the second stirring blades,

The method for producing an optical film according to any one of 1 to 6 above, wherein the third stirring blade is a turbine-type or disk-type stirring blade.

8. The stirring jig according to any one of 1 to 7 above, wherein the first stirring jig has a plurality of the arm portions at the same angular intervals around the first rotation axis in a plane perpendicular to the first rotation axis Gt;

9. The stirring jig according to any one of claims 1 to 8, wherein a plurality of the second stirring jigs are provided at the same angular intervals around the first rotation axis in a plane perpendicular to the first rotation axis of the first stirring jig The method for producing an optical film according to any one of 1 to 8 above.

10. The method for producing an optical film according to 8 or 9, wherein the same angular interval is 180 DEG.

INDUSTRIAL APPLICABILITY The present invention is applicable to the production of an optical film by a solution casting method.

101: stirring tank
101a:
111: first stirring jig
112: first rotating shaft
112a:
113:
113a:
121: second stirring jig
122: second rotating shaft
123: stirring wing
123a: first stirring blade
123b: second stirring blade
123c: third stirring blade
A: Location
F: Optical film
S1: Stirring preparation process
S2: Flexible process

Claims (10)

A method for producing an optical film by a solution casting method,
A stirring and mixing step of stirring at least a resin and a solvent in a stirring tank to prepare a dope,
And a softening step of softening the dope prepared in the stirring and mixing step on a support,
The resin is any one of an acrylic resin, a cycloolefin resin, and a polyarylate resin,
When the specific gravity of the resin is A, the specific gravity of the solvent is B, and the specific gravity difference (BA) is DELTA,
0.1 <
Lt;
In the stirring tank, a first stirring jig and a second stirring jig are provided,
Wherein the first stirring jig includes a first rotating shaft located on a vertical axis passing through the center of the bottom surface of the stirring tank and a second rotating shaft located above the lowermost portion in the stirring tank from the lowermost portion of the first rotating shaft, And an arm portion extending from the rotation axis to a position spaced apart in the radial direction of rotation,
The second stirring jig includes the second rotation shaft extending in the vertical direction so as to pass through the space between the first rotation shaft and the arm portion and at least two stirring wings attached to the second rotation shaft so as to be arranged along the vertical direction Have,
A length of the arm portion of the first stirring jig is L and a stirring blade of the uppermost one of the at least two stirring blades of the second stirring jig and a stirring blade located below the one of the at least two stirring blades of the second stirring jig are respectively referred to as first When a stirring blade and a second stirring blade are used,
Wherein the first stirring vane includes a position vertically downwardly downward (1/3) L from the uppermost portion of the arm portion of the first stirring jig and is located above the first stirring vane, and is rotated by the rotation about the second rotation axis And a stirring blade for causing a flow of the resin in the vertical direction,
Wherein the second stirring blade is located below a position vertically downwardly downward by (1/3) L from the uppermost portion of the arm portion of the first stirring jig, and by rotation about the second rotation axis, And a stirring blade for causing a flow in a direction perpendicular to the second rotation axis of the resin drawn vertically downward by a stirring blade. The method according to claim 1,
0.1 <
, Wherein the optical film has a thickness of 100 nm or less. 3. The method according to claim 1 or 2,
Wherein the solvent comprises methylene chloride or chloroform. 4. The method according to any one of claims 1 to 3,
Wherein the first stirring blade is a stirring blade of a paddle type or a propeller type. 5. The method according to any one of claims 1 to 4,
Wherein the second stirring blade is a turbine type or disk type stirring blade. 6. The method according to any one of claims 1 to 5,
Wherein the first stirring jig is composed of an agitating blade of an anchor type or an anchor paddle type. 7. The method according to any one of claims 1 to 6,
The second stirring jig further includes a third stirring blade located under one of the second stirring blades,
Wherein the third stirring blade is a turbine or disk type stirring blade. 8. The method according to any one of claims 1 to 7,
Wherein the first stirring jig has a plurality of arm portions at a same angular interval around the first rotation axis in a plane perpendicular to the first rotation axis. 9. The method according to any one of claims 1 to 8,
Wherein a plurality of the second stirring jigs are provided at the same angular intervals around the first rotation axis in a plane perpendicular to the first rotation axis of the first stirring jig in the stirring tank. &Lt; / RTI &gt; 10. The method according to claim 8 or 9,
Wherein the same angular interval is 180 DEG apart.

Images