JP2003211468A - Film manufacturing method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film manufacturing method and device by which a high- quality film with a planar appearance can be manufactured certainly. <P>SOLUTION: The film manufacturing device 10 has guide rollers 36A to 36D mounted between a drive drum 24 and a driven drum 26. The guide rollers 36A to 36D are arranged in row and at an equal interval L1 so that the top point of the guide rollers 36A to 36D are set at the same height as the top point of the drums 24 and 26. The guide roller 36A is arranged so that a distance L2 between the guide roller 36A and the drive drum 24 is smaller than the interval L1 and the guide roller 36D is arranged so that a distance L3 between the guide roller 36D and the driven drum 26 is smaller than the interval L1. The tension of a casting band 22 is adjusted by sliding the driven drum 26 by means of a cylinder 42 and the casting band 22 is adjusted so that it comes into contact with each of the guide rollers 36A to 36D at a specified wrap angle θ. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film manufacturing method and apparatus, and more particularly to a film for manufacturing a polarizing plate film, an optical film, an LCD film, an organic EL film, etc. by a casting band film forming method. The present invention relates to a manufacturing method and device.

[0002]

2. Description of the Related Art A protective film for a polarizing plate used in a liquid crystal display device and a film base for a photographic light-sensitive material have good transparency, large mechanical strength, and a dimensional change due to temperature change and heat. Cellulose ester films are used because of the need for small (ie, good dimensional stability) characteristics.

The cellulose ester film is usually produced by a solution casting method. That is, a cellulose ester film is produced by casting a dope (concentrated solution) from a casting die onto an endless support, and peeling the dope from the endless support after it has self-supporting properties.

As the endless support used in the solution casting method, for example, a casting band is used. Casting band
One metal (for example, stainless steel) strip plate is formed into an endless annular shape by welding both ends in the longitudinal direction to each other, and the endless annular casting bands are arranged at a predetermined interval. Wrapped around the drum. As a method of attaching the casting band to the pair of drums, there are an endless band type and an open band type. The endless band type is a method in which a band-shaped plate is formed into an endless annular casting band and then wound around a pair of drums.The open band type is a welding method in which the band-shaped plate is wrapped around a pair of drums and welded. It is to make a band. The endless annular casting band thus wound around the pair of drums runs by rotating at least one of the pair of drums.

The above-mentioned dope is cast on the surface of the casting band during running. Therefore, if the casting band becomes unstable while running, it may cause unevenness in the film. Therefore, in order to produce a uniform film, it is necessary to stabilize the casting band during running.

Therefore, conventionally, as shown in FIG. 5, a plurality of guide rollers 3, 3 are arranged between a pair of drums 1, 1 and the back surface of the casting band 2 is formed by the guide rollers 3, 3. Is guiding you. The guide rollers 3, 3 ... Are rotatably supported, and are arranged at a higher position toward the center side (that is, arranged in a convex shape as a whole). As a result, the casting band 2 contacts each guide roller 3 at a predetermined holding angle (0.01 to 1.0 °),
The guide roller 3 presses the casting band 2 to the outside while rotating along with the traveling casting band 2 to stabilize the casting band 2.

[0007]

However, in the conventional film manufacturing apparatus, when the tension applied to the casting band 2 is increased in order to further stabilize the running property of the casting band 2, the cracking of the casting band 2 occurs. And the like, and as a result, streak-like unevenness may occur on the outer surface of the film. In particular, when the casting band 2 was attached by the open band method, the unevenness of the film was sometimes remarkable. In order to improve the quality of the surface appearance of the film, it is necessary to pursue the cause of this unevenness and eliminate it.

The present invention has been made in view of the above circumstances, and provides a film manufacturing method and apparatus capable of reliably manufacturing a film having good running properties of a casting band and excellent appearance surface quality. The purpose is to provide.

[0009]

In order to achieve the above object, the invention described in claim 1 runs on an endless casting band wound around a pair of drums arranged at a predetermined interval. And casting a dope on the outer surface of the casting band, and peeling the dope from the casting band to produce a film, wherein a plurality of guide rollers are provided between the pair of drums. Are arranged in a line in a straight line to guide the back surface of the casting band, and the tension of the casting band is adjusted so that the casting band comes into contact with the guide roller at a predetermined wrapping angle by its own weight. It is characterized by doing.

In order to achieve the above object, the invention according to claim 2 runs an endless casting band wound around a pair of drums arranged at a predetermined interval, and the casting band. The dope is cast on the outer surface of the dope, in a film production apparatus for producing a film by stripping the dope from the casting band, the dope is arranged linearly in a line between the pair of drums, A plurality of guide rollers for guiding the back surface of the spreading band; and tension adjusting means for adjusting the tension of the casting band so that the casting band comes into contact with the guide rollers at a predetermined wrap angle by its own weight. It is characterized by having.

In order to achieve the above object, the invention according to claim 3 runs an endless casting band wound around a pair of drums arranged at a predetermined interval, and the casting band. In the film manufacturing method of casting a dope on the outer surface of the dope, to produce a film by stripping the dope from the casting band, a plurality of guide rollers are linearly arranged in a line between the pair of drums. The guide band is arranged to guide the back surface of the casting band, and the distance between the guide roller arranged closest to the drum among the plurality of guide rollers and the drum is smaller than the distance between the guide rollers. Is characterized by.

In order to achieve the above object, the invention according to claim 4 runs an endless casting band wound around a pair of drums arranged at a predetermined interval, and the casting band is run. The dope is cast on the outer surface of the dope, in a film production apparatus for producing a film by stripping the dope from the casting band, the dope is arranged linearly in a line between the pair of drums, A guide roller provided with a plurality of guide rollers for guiding the back surface of the stretched band, and the guide roller arranged on the most drum side among the guide rollers has a distance between the guide roller and the drum that is larger than a distance between the guide rollers. It is characterized by being small.

The inventor of the present invention has found that as a cause of unevenness, guide rollers arranged in a convex shape in order to stabilize the running property of the casting band may be a new cause of unevenness. That is, if the guide roller is arranged in a convex shape in order to stabilize the running property of the casting band, a strong pressing force is applied from the guide roller to the casting band, and the physical influence on the back surface of the casting band (unevenness or foreign matter). It has been found that (mixture) affects even the surface side and causes streaky unevenness. Furthermore, in order to stabilize the running performance of the casting band, if a higher tension is applied, the above problem becomes noticeable and the band will be broken, so that both running stability and quality assurance are achieved. Was difficult. In particular, when the casting band is attached with the open band type, dust and dust are likely to be generated because the welding work is performed on site, and when these adhere to the back surface of the casting band and are pressed by the guide roller. In addition, it was found that the film cast on the surface of the casting band was affected, and the appearance of the film was uneven.

Therefore, the inventor of the present invention changes the conventional idea of strongly pressing and stabilizing the casting band with the guide roller to adjust the tension of the casting band to an appropriate range, or to cast the casting band. By arranging the guide roller at the most unstable part of the band, the casting band is stabilized with a minimum pressing force.

Specifically, as described in claims 1 and 2, a plurality of guide rollers are linearly arranged in a line so that the casting band has a predetermined wrapping angle with respect to the guide rollers by its own weight. The tension of the casting band was adjusted. As a result, the casting band comes into contact with the guide roller with an appropriate pressing force and rotates together with the casting band, so that the physical influence of the back surface of the casting band can be prevented from affecting the film on the front surface side. Therefore, the appearance quality of the film can be improved. In addition, "arranging a plurality of guide rollers in a straight line in a row" means that the uppermost portions of the guide rollers are in contact with the straight line connecting the uppermost portions of the two drums. Therefore, the diameter of the guide roller does not matter as long as the uppermost portion is linear.

Further, in the invention described in claims 3 and 4, the plurality of guide rollers are linearly arranged in a line, and
The distance between the guide roller closest to the drum and the drum is set smaller than the distance between the guide rollers. Casting band
Since it becomes the most unstable in the vicinity of the drum, by arranging the guide roller in this portion, the casting band becomes stable without applying a strong pressing force to the casting band. Further, since the guide rollers are linearly arranged in a line, the pressing force of the guide rollers does not increase even when the tension of the casting band is increased. Therefore, according to the third and fourth aspects of the present invention, the casting band is stabilized with a small pressing force, so that the quality of the surface appearance of the film can be improved.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the film manufacturing method and apparatus according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a conceptual diagram showing the overall structure of a film manufacturing apparatus according to the present invention.

As shown in the figure, the film manufacturing apparatus 10
Is mainly composed of a casting process unit 12, a stretching and drying process unit 14, a drying process unit 16, and a winding process unit 18. The casting process unit 12 includes a casting die 20, a casting band 22, and a driving drum 24. , And a driven drum 26 are provided. A dope such as a cellulose triacetate solution is supplied to the casting die 20 through a supply line 28, and the dope is extruded from the tip of the casting die 20 onto the casting band 22 and cast.

The type of solvent for the dope is not particularly limited as long as it can dissolve the polymer. The concentration of the polymer in the solution depends on the kind of the polymer, but is generally 3 to 50 wt%, and in the solution, other than the polymer and the solvent, a lubricant, a plasticizer, conductive particles, Antioxidants, UV absorbers, and other additives may be blended. Examples of the polymer include aromatic polyamide, aromatic polyimide, polyarylate, polycarbonate, cellulose polymers such as cellulose diacetate and cellulose triacetate, vinyl acetate, polyvinyl alcohol and the like.

The casting band 22 is an endless belt in which the ends of strip-shaped plates are joined together to form an endless belt. The material of the casting band 22 is iron, stainless steel (SU
S), nickel, titanium, tantalum, copper or the like, and the surface thereof may be plated with chromium or nickel or surface-treated.

Further, the casting band 22 preferably has a thickness of 0.5 to 3 mm which provides good flatness. More preferably, it has a thickness of 1 to 2 mm. Also, casting band 2
The width of 2 is preferably wide from the viewpoint of productivity, but is preferably 1 to 4 m in terms of use.

Further, the surface roughness of the casting band 22 is preferably 0.5 μm or less, and more preferably 0.1 μm or less in the maximum height Rt in both the welded portion and the non-welded portion. Surface roughness is 0.
If it is larger than 5 μm, the surface of the film becomes rough, which is not preferable. In order to improve surface properties, corrosion resistance, and hardness, the casting band 22 may be made of chromium, gold, or
You may perform plating or surface treatment of silver, nickel, etc.

The casting band 22 is wound around the driving drum 24 and the driven drum 26, and runs by rotating the driving drum 24. Casting band 22 while running
The dope cast above is peeled off from the casting band 22 after being self-supporting. Peeled film 30
Is first dried in the stretching and drying step section 14, and further dried in the drying step section 16.

The stretching / drying process section 14 is provided with a tenter 32 for drying the film 30 while stretching the film 30 in the width direction. On the other hand, the drying process unit 16 is provided with transport rolls 34, 34 ...
The film 30 is conveyed while being wrapped around it, and the film 30 is dried by blowing dry air. The film 30 thus dried is wound into a roll in the winding step unit 18.

By the way, the driving drum 24 and the driven drum 2
Between 6 are four guide rollers 3 as shown in FIG.
6A to 36D are installed. Each guide roller 36A
The outer diameters of ~ 36D are formed with a diameter of approximately 50 mm to 200 mm, and are rotatably supported so that they can be rotated with the casting band 22. In addition, each guide roller 36
A to 36D may be configured to be rotationally driven in accordance with the running flow band 22. Further, in the present embodiment, the guide rollers 36A to 36D are four, but
The number is not limited to this, and the number can be selected as necessary.

The guide rollers 36A to 36D are arranged horizontally in a line as shown in FIG. Specifically, the four guide rollers 36A to 36D have an equal interval L1 (for example, 500 to 5000 m) so that their uppermost points have the same height as the uppermost points of the driving drum 24 and the driven drum 26.
m).

The guide roller 36A closest to the drive drum 24 is arranged so that the distance L2 from the drive drum 24 is smaller than the distance L1 between the guide rollers 36A to 36D. Further, the guide roller 36D installed on the driven drum 26 side is arranged such that the distance L3 from the driven drum 26 is smaller than the distance L1 between the guide rollers 36A to 36D. In particular, the guide roller 36A is arranged as close to the drive drum 24 as possible within a range that does not affect the drive drum 24. When the casting band 22 is guided by the guide rollers 36A and 36D arranged in this way, the fluctuation of the casting band 22 can be efficiently suppressed.

The drive drum 24 is rotatably supported and connected to a motor 38 via a belt 40. As a result, the rotational driving force of the motor 38 is applied to the belt
It is transmitted to the drive drum 24 via 0, and the drive drum 24 rotates. The driving drum 24 and the driven drum 26 generally have an outer diameter of 500 to 4000 mm and a width of 500 to 50 mm.
00 mm is used.

On the other hand, the driven drum 26 is horizontally (see FIG. 3).
Is supported slidably in the direction of the arrow), and the bar 44 is attached to the rod 44 of the cylinder 42 that is horizontally expandable and contractible.
It is connected via 6. Therefore, the cylinder 42
When the rod 44 is expanded and contracted, the driven drum 26 moves in the arrow direction, and the tension of the casting band 22 is adjusted.
The tension is preferably 10 to 200 N / mm ² , 20
-100 N / mm ² is more preferable. At this time, the widthwise traveling position of the casting band 22 can be made constant by controlling the operation of the cylinder 42. The tension of the casting band 22 is as shown in FIG.
Is set to have a predetermined holding angle θ with respect to the guide roller 36A (or 36B to 36D). That is,
Since the casting band 22 is bent (suspended) by its own weight, it is adjusted to have a predetermined holding angle θ. Here, the predetermined holding angle θ means that the casting band 22 has the respective guide rollers 36A.
To 36D and the direction in which the casting band 22 is sent out from each of the guide rollers 36A to 36D, and is preferably set to 0.01 to 1.0 °. It should be noted that the drum 26 is not limited to the driven type, and a separate driving method or a driving method connected to the driving drum 24 may be selected.

The guide roller 36D may be configured to slide along with the driven drum 26.
As a result, even if the driven drum 26 slides, the relative positional relationship with the guide roller 36D does not change, and the casting band 22 can always be stabilized.

Next, the operation of the film manufacturing apparatus 10 configured as described above will be described.

The casting drum 2 is rotated by rotating the driving drum 24.
If the casting band 22 fluctuates and moves in an unstable manner during traveling of No. 2, the dope cast from the casting die 20 is adversely affected and unevenness occurs. Also, this casting band 2
2 in order to prevent the fluctuation of the guide rollers 36A to 36A.
When the casting band 22 was strongly pressed and supported by D, the physical influence of the back surface of the casting band 22 and the surfaces of the guide rollers 36A to 36D, or foreign matter between them was cast on the band surface. There is a problem that unevenness is generated by being transmitted to the film 30.

Therefore, the film manufacturing apparatus 10 of the present embodiment is designed to stabilize the casting band 22 without pressing it strongly. For example, the guide roller 36A and the drive drum 2
4 and the distance L3 between the guide roller 36D and the driven drum 26 are smaller than the distance L1 between the guide rollers 36A to 36D. As a result, the guide rollers 36A and 36D are arranged close to the drive drum 24 and the driven drum 26, respectively.
Can be efficiently suppressed. Therefore, it is not necessary to strongly press the casting band 22 with the guide rollers 36A to 36D, and the casting band 22 can be pressed with a small pressing force.
Can be stabilized. In addition, the guide roller 36A
~ By changing the arrangement of 36D, guide roller 36A ~
Since the casting band 22 can be stabilized without increasing the number of 36D, the resistance of the guide rollers 36A to 36D with respect to the running casting band 22 does not increase.

Further, in the film manufacturing apparatus 10, the tension of the casting band 22 is adjusted so that the casting band 22 comes into contact with the guide rollers 36A to 36D at a predetermined holding angle θ. That is, since the casting band 22 is bent by its own weight to come into contact with the guide rollers 36A to 36A, the casting band 22 can be stabilized without being strongly pressed.

Further, in the film manufacturing apparatus 10, the guide rollers 36A to 36D, the uppermost point of which is the drive drum 24,
The guide rollers 36A to 36D are arranged linearly in a line so that they are at the same height as the highest point of the driven drum 26.
It is possible to prevent the pressing force from being excessive. That is, when the guide roller 3 is arranged as shown in FIG.
When the tension of the casting band 1 is increased, the pressing force of the guide roller 3 becomes excessive, and problems such as unevenness are likely to occur. On the other hand, in the present embodiment shown in FIG. 3, when the tension of the casting band 22 is increased, the pressing force by the guide rollers 36A to 36D is reduced, and therefore the pressing force can be prevented from becoming excessive. It is possible to reliably prevent the occurrence of defects such as unevenness.

As described above, according to the film manufacturing apparatus 10 of the present embodiment, the casting band 22 can be stabilized without being strongly pressed, so that the back surface of the casting band 22 and the guide rollers 36A to 36D are formed. The physical influence of the surface or foreign matter between the two is not transmitted to the film 30 cast on the surface of the band, and the appearance quality of the film 30 can be improved.

Further, since the film manufacturing apparatus 10 does not strongly press the casting band 22, a large load is not applied to the casting band 22 and the guide rollers 36A to 36D, and the casting band 22, the driving drum 24, and the driven drum. 26, and the life of the guide rollers 36A to 36D can be improved.

Although the four guide rollers 36A to 36D are installed in the above-described embodiment, the number of the guide rollers 36A to 36D is not limited to this, and may be two or more.

Further, in the above-mentioned embodiment, the four guide rollers 36A to 36D are arranged at the equal intervals L1, but the present invention is not limited to this and may be arranged at different intervals. Also in this case, the four guide rollers 36A
It is preferable that the distance L2 or the distance L3 be smaller than any of the intervals of 36D.

Further, each of the guide rollers 36A to 36D (in particular, the guide rollers 36A and 36D) is preferably constructed so that its position can be adjusted in the horizontal direction.

Further, in the above-described embodiment, the distance L
Although 2 and L3 were made smaller than the interval L1 and adjusted to a predetermined holding angle θ at the same time, they may be performed separately, and even when they are performed separately, the appearance surface quality of the film 30 may be different. The effect of improving can be obtained.

[0043]

As described above, according to the film manufacturing method and apparatus of the present invention, a plurality of guide rollers are arranged in a straight line, and the casting band has a predetermined wrapping angle with respect to the guide rollers. The tension of the casting band is adjusted so that the casting band is stable, even if the casting band is not strongly pressed. Therefore, the physical influence of the back surface of the casting band is less likely to be transmitted to the film on the front surface side, and the quality of the surface appearance of the film can be improved.

Further, according to the present invention, the plurality of guide rollers are linearly arranged in a line, and the distance between the guide roller on the most drum side and the drum is set smaller than the distance between the guide rollers. The spreading band is easily stabilized, and the casting band can be stabilized with a small pressing force. Therefore, the physical influence of the back surface of the casting band is less likely to be transmitted to the film on the front side, and the appearance quality of the film can be improved.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing the overall configuration of a film manufacturing apparatus according to the present invention.

FIG. 2 is a perspective view showing a configuration of a casting process unit.

FIG. 3 is a side view showing a configuration of a casting process unit.

FIG. 4 is an explanatory view showing a holding angle of a casting band with respect to a guide roller.

FIG. 5 is a side view showing the configuration of a conventional casting process unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Film manufacturing apparatus, 12 ... Casting process part, 14 ... Stretching / drying process part, 16 ... Drying process part, 18 ... Winding process part,
20 ... Casting die, 22 ... Casting band, 24 ... Driving drum, 26 ... Followed drum, 28 ... Supply line, 30 ... Film, 32 ... Tenter, 34 ... Conveying roll, 36A to 3
6D ... Guide roller, 38 ... Motor, 40 ... Belt, 4
2 ... Cylinder, 44 ... Rod, 46 ... Bar

Claims (4)

[Claims] 1. An endless casting band wound around a pair of drums arranged at predetermined intervals is run, and the dope is cast on the outer surface of the casting band. In the film manufacturing method of manufacturing a film by stripping from the casting band, while guiding the back surface of the casting band by linearly arranging a plurality of guide rollers between the pair of drums, A film manufacturing method comprising adjusting the tension of the casting band so that the casting band comes into contact with the guide roller by its own weight at a predetermined wrapping angle. 2. An endless casting band wound around a pair of drums arranged at predetermined intervals is run, and the dope is cast on the outer surface of the casting band. In the film manufacturing apparatus for manufacturing a film by stripping from the casting band, linearly arranged in a line between the pair of drums,
A plurality of guide rollers for guiding the back surface of the casting band, and tension adjusting means for adjusting the tension of the casting band so that the casting band comes into contact with the guide rollers by its own weight at a predetermined wrap angle. A film manufacturing apparatus comprising: 3. An endless casting band wound around a pair of drums arranged at predetermined intervals is run, and the dope is cast on the outer surface of the casting band, and the dope is cast. In the film manufacturing method of manufacturing a film by stripping from the casting band, while guiding the back surface of the casting band by linearly arranging a plurality of guide rollers between the pair of drums, Among the plurality of guide rollers, the distance between the guide roller disposed closest to the drum and the drum is set smaller than the distance between the guide rollers. 4. An endless casting band wound around a pair of drums arranged at predetermined intervals is run, and the dope is cast on the outer surface of the casting band. In the film manufacturing apparatus for manufacturing a film by stripping from the casting band, linearly arranged in a line between the pair of drums,
A plurality of guide rollers for guiding the back surface of the casting band are provided, and among the guide rollers, the guide roller arranged closest to the drum has a space between the guide roller and the drum,
A film manufacturing apparatus characterized in that it is smaller than the interval between the guide rollers.