JP7446710B2 - How to pass optical film - Google Patents

Description

The present invention relates to a method for passing an optical film such as a raw film of a polarizing film. In particular, the present invention relates to a method for passing an optical film that is less likely to cause defects in the appearance of the optical film.

Conventionally, optical films have been used in image display devices such as liquid crystal display devices and organic EL display devices. Examples of the optical film include a polarizing film (polarizer), a polarizing plate including a polarizing film, a retardation film, and an anti-glare film.
Optical films are usually manufactured using long strip-shaped raw films. Normally, a long strip-shaped optical film is manufactured as a product by sequentially carrying out various treatments while carrying the original film in the longitudinal direction using a carrying facility having carrying rollers (for example, Patent Documents 1 and 2). reference). The long strip-shaped optical film is cut into a size according to the intended use and used in image display devices and the like.
Hereinafter, in this specification, not only an optical film as a product but also a raw film and an intermediate product film will be referred to as an optical film.

For example, when the optical film is a polarizing film, the raw film can be immersed in processing baths in multiple processing tanks in order while being conveyed by a conveying equipment. In addition to dyeing with a dichroic substance such as, uniaxial stretching is performed (see, for example, Patent Document 2).

When starting the production of optical film products, it is necessary to pass the optical film through the pass line (the optical film transport path determined by the position of the transport roller) of the transport equipment that has the transport rollers mentioned above. There is. Paper passing is an operation in which a person manually pulls the leading end of the optical film, wraps the optical film around the conveyance roller, and aligns the optical film along the pass line.

For example, when the optical film is a polarizing film, one raw film and the next raw film are spliced (the rear end of one raw film and the leading edge of the next raw film). ) cannot be transported. This is because the original film of the polarizing film is subjected to a stretching process in a processing bath, so even if it is spliced using a general tape or laser welding, the spliced portion will come off. Therefore, each time the original film wound around the feeding roller runs out, the next original film wound around the feeding roller is passed by hand.

Conventionally, when passing an optical film through the above-mentioned processing tank, the optical film is not immersed in the processing bath in the processing tank, but is passed through a conveying roller provided in the processing tank, and after the paper passing operation is completed. , it was common to immerse the optical film in a processing bath. Specifically, the optical film is passed through the optical film without being immersed in the processing bath with the lifting roller, which is a transport roller that can be raised and lowered within the processing tank, raised above the liquid level of the processing bath in the processing tank. After the paper passing operation is completed, it has been common practice to lower the elevating roller to immerse the optical film in the processing bath.
In the conventional paper passing method described above, the optical film may be rubbed or cut. Particularly, the thinner the optical film, such as the original film of the polarizing film, is, the more likely it is to be scratched or cut during the paper passing operation. Even if the leading edge of the optical film is scratched or scratched, no particular problem will occur as long as the leading edge is not used as a product.
However, due to abrasion or breakage of the optical film, unevenness may occur on the surface of the conveyance roller (usually made of rubber material), or foreign matter made of the material forming the optical film or the rubber material on the surface of the conveyance roller may occur. Problems may arise. Specifically, once unevenness occurs on the surface of the conveyance roller, it cannot be corrected until it is replaced, so the unevenness on the surface of the conveyance roller is transferred to the optical film during normal conveyance after the sheet passing operation is completed. The optical film may have poor appearance. Further, the generated foreign matter floats for a long time in the atmosphere where the optical film transport equipment is provided or in the processing tank, so that the foreign matter may adhere to the optical film and cause the optical film to have a poor appearance. For example, even if unevenness or foreign matter with a size of about several tens of micrometers is visible in an optical film, it may result in poor appearance and lead to a decrease in product yield. For this reason, it is desired to prevent as much as possible the appearance defects of the optical film due to abrasion or tearing of the optical film that occurs during the paper passing operation.

Japanese Patent Application Publication No. 2013-248590 Japanese Patent Application Publication No. 2004-341515

The present invention has been made in order to solve the problems of the prior art as described above, and an object of the present invention is to provide a method for passing an optical film in which poor appearance of the optical film is unlikely to occur.

In order to solve the above-mentioned problem, the inventors of the present invention conducted extensive studies and found that one of the causes of scratches and cuts during paper passing is the hardness of the optical film. Specifically, conventionally, the optical film is hard because it is not immersed in the processing bath during paper passing, and the optical film is easily scratched or cut due to friction with the conveyance roller during paper passing. I understand.

The present invention was completed based on the above findings of the present inventors.
That is, in order to solve the above-mentioned problem, the present invention provides an optical film manufacturing facility that includes a transport facility having a plurality of transport rollers and a plurality of processing tanks, in which an optical film is passed through a pass line of the transport equipment. The method comprises: immersing the optical film in a processing bath located upstream in the transporting direction of the optical film; The optical film is passed through a roller , and the manufacturing equipment includes, as the plurality of processing tanks, a cleaning processing tank that performs a washing process on the optical film in order from the downstream side in the conveying direction of the optical film, and a cleaning processing tank that performs a washing process on the optical film; A stretching treatment tank for performing a stretching treatment and an upstream treatment tank for applying a predetermined treatment to the optical film are provided, and the tip of the optical film that has been immersed in the treatment bath in the upstream treatment tank is cut off. After that, the optical film following the cut tip portion is passed through conveyance rollers provided in the stretching treatment tank and the cleaning treatment tank, and among the conveyance rollers provided in the stretching treatment tank, the stretching treatment An elevating roller, which is a transport roller that can be raised and lowered within the tank, is raised above the liquid level of the processing bath in the stretching tank, and among the transport rollers provided in the cleaning tank, the The optical film is transferred to the processing bath in the stretching processing tank and the cleaning processing tank while the lifting roller, which is a transport roller that can be raised and lowered, is raised above the liquid level of the processing bath in the cleaning processing tank. After passing the paper through the conveying rollers provided in the stretching treatment tank and the cleaning treatment tank without immersing it in the treatment bath, the lifting roller provided in the cleaning treatment tank is moved to the liquid of the treatment bath in the cleaning treatment tank. The optical film is lowered below the surface to immerse the optical film in the processing bath in the cleaning treatment tank, and then the lifting roller provided in the stretching treatment tank is lowered from the liquid level of the treatment bath in the stretching treatment tank. Provided is a method for passing an optical film, in which the optical film is lowered downward and the optical film is immersed in a treatment bath in the stretching treatment tank . The pass line means a conveyance path of the optical film determined by the position of the conveyance roller, and the paper passing means that a person manually pulls the leading end of the optical film to cause the optical film to pass through the conveyance roller. It means the operation of applying the above-mentioned optical film along the above-mentioned pass line.

According to the present invention, after the optical film is immersed in the processing bath located in the processing tank located upstream in the transport direction of the optical film, the transport roller provided in the processing tank located downstream in the transport direction of the optical film is immersed. An optical film will be passed through it. In other words, when an optical film is passed through a transport roller provided in a processing tank located on the downstream side in the transport direction, the optical film is immersed in the processing bath in the processing tank located on the upstream side in the transport direction. Therefore, the optical film is softened, and the optical film is less likely to be scratched or cut when the paper is passed through a conveyance roller provided in a processing tank located downstream in the conveyance direction. As a result, appearance defects are less likely to occur in the optical film.
In the present invention, the optical film is immersed in a processing bath located in a processing tank located upstream in the transport direction by passing the optical film through a transport roller provided in a processing tank located upstream in the transport direction. This may be done later, or the optical film may be immersed while being passed through the paper.

According to the present invention, the manufacturing equipment includes, as the plurality of treatment tanks, a cleaning treatment tank for performing a cleaning treatment on the optical film, and a stretching treatment for the optical film, in order from the downstream side in the conveyance direction of the optical film. comprising a stretching treatment bath and an upstream treatment bath for subjecting the optical film to a predetermined treatment; after cutting off the tip of the optical film that has been immersed in the treatment bath in the upstream treatment bath, The optical film following the tip end is passed through conveyance rollers provided in the stretching tank and the cleaning tank.

For example, when the upstream processing tank consists of a plurality of processing tanks, the optical film immersed in the processing bath in the upstream processing tank may be repeatedly passed through paper and immersed (or repeatedly immersed while passing paper). There is a risk that it will become too soft. On the other hand, in the stretching treatment tank, the treatment bath is generally at a high temperature. For this reason, there is a risk that the optical film may be cut or melted if the optical film is immersed in the treatment bath of the stretching treatment bath.
According to the present invention, after the tip of the optical film that has been immersed in the processing bath in the upstream processing tank is cut off, the optical film following the cut tip is placed in the stretching processing tank and the cleaning processing tank. The paper will pass through the transport rollers. Specifically, the tip of the optical film that has been immersed in the processing bath in the upstream processing tank is wound up with a portable take-up roller, the rear end of this tip is cut off, and the tip is recovered. It is possible that Since the sheet feeding work to the conveying roller installed in the upstream processing tank has been completed, by winding up the leading end of the optical film with a portable take-up roller, the optical film following the leading end can be transported to the upstream processing tank. It will be immersed in the processing bath in the side processing tank. For this reason, the optical film following the leading end portion is softened, making it difficult for the optical film to be scratched or cut when it passes through the conveyance rollers provided in the stretching tank and the cleaning tank. Also, compared to the time that the tip of the cut optical film was immersed in the processing bath in the upstream processing tank, the time that the optical film following the tip was immersed in the processing bath in the upstream processing tank was longer. (The immersion time for the leading edge is longer by the time required for the paper to pass through the conveyance roller provided in the upstream processing tank), which may cause excessive softening of the optical film following the leading edge. Therefore, it is possible to suppress the risk of cutting or melting in the treatment bath of the stretching treatment tank.

According to the present invention, among the conveyance rollers provided in the stretching treatment tank, the lifting roller, which is a conveyance roller that can be raised and lowered in the stretching treatment tank, is positioned above the liquid level of the processing bath in the stretching treatment tank. At the same time, among the conveyance rollers provided in the cleaning treatment tank, a lifting roller, which is a conveyance roller that can be raised and lowered in the cleaning treatment tank, is raised above the liquid level of the processing bath in the cleaning treatment tank. After passing the optical film through a conveying roller provided in the stretching tank and the cleaning tank without immersing the optical film in the processing bath in the stretching tank and the cleaning tank. , the optical film is immersed in the processing bath in the cleaning tank by lowering a lifting roller provided in the cleaning tank below the liquid level of the processing bath in the cleaning tank; An elevating roller provided in the stretching tank is lowered below the liquid level of the processing bath in the stretching tank to immerse the optical film in the processing bath in the stretching tank.

According to the present invention, the optical film is first immersed in a treatment bath in a cleaning treatment tank, and then immersed in a treatment bath in a stretching treatment tank. In this way, by immersing in the processing bath in the cleaning treatment tank before the treatment bath in the stretching treatment tank, the time required for immersion in the high temperature treatment bath in the stretching treatment tank is reduced compared to when the order is reversed. This makes it possible to further suppress the possibility that the optical film will be cut or melted.

In the present invention, among the conveyance rollers provided in the processing bath located upstream in the conveyance direction of the optical film, the elevating roller, which is a conveyance roller that can be raised and lowered within the processing bath, is used to remove the liquid of the processing bath in the processing bath. After passing the optical film through the transport roller in a state where the optical film is raised above the surface, the elevating roller is lowered below the liquid level of the processing bath to immerse the optical film in the processing bath. It is preferable to let

According to the above preferred method, it is possible to reliably immerse the optical film in the processing bath.
However, the present invention is not limited to this. For example, the optical film may be loosened between the lifting rollers while passing the optical film with the lifting rollers raised above the liquid level of the processing bath. It is also possible to adopt a method of immersing the material in a treatment bath.

In the present invention, the upstream treatment tank includes, in order from the upstream side in the transport direction of the optical film, a swelling treatment tank that applies a swelling treatment to the optical film, a dyeing treatment tank that applies a dyeing treatment to the optical film, and a dyeing treatment tank that applies a dyeing treatment to the optical film. An example of this is a crosslinking treatment tank that performs crosslinking treatment.

In the above preferred method, when a plurality of lifting rollers are provided as the lifting rollers in the transporting direction of the optical film in a processing tank located upstream in the transporting direction of the optical film, the plurality of lifting rollers are When descending below the liquid level, it is preferable to descend in sequence.

According to the above preferred method, the inclination angle (angle with the horizontal plane) of the optical film pushed by the first lowering roller becomes larger than when all the lifting rollers are lowered at the same time. This makes it easier for air bubbles accumulated on the lower surface of the optical film to pass through the optical film, making it difficult for problems caused by air bubbles to occur during the treatment applied to the optical film in the treatment bath.

Note that, if there are lifting rollers among the plurality of lifting rollers whose positions in the vertical direction after lowering are different from each other, it is preferable that the lifting roller whose position after lowering is the lowest is lowered first. Lowering the lifting roller that will be at the lowest position first will cause the tilt angle of the optical film to be larger than lowering the lifting roller that will be at a higher position after lowering, which will prevent air bubbles. This is because it becomes easier to come off.

The present invention is suitably used when the optical film is an original film of a polarizing film (including a film of an intermediate product).

According to the present invention, when the optical film is passed through, the optical film is less likely to be scratched or cut, and the optical film is less likely to have a poor appearance.

1 is a schematic diagram illustrating an example of a schematic configuration of a manufacturing facility for a polarizing plate manufactured from a raw film to which a paper passing method according to an embodiment of the present invention is applied. FIG. 2 is a schematic diagram showing an example of a schematic configuration of a processing tank shown in FIG. 1 and a conveying facility provided in the processing tank. Using the paper passing method according to an embodiment of the present invention, a procedure for passing a raw film through a pass line determined by a conveyance roller provided in a swelling treatment tank shown in FIG. 2, and immersing the raw film in a processing bath. It is an explanatory diagram showing a procedure to do. FIG. 3 is a diagram showing another example of the elevating roller provided in the swelling treatment tank shown in FIG. 2; FIG. 3 is an explanatory diagram showing the procedure of paper passing and dipping in a stretching treatment tank and a cleaning treatment tank using a paper passing method according to an embodiment of the present invention.

Hereinafter, with appropriate reference to the accompanying drawings, a method for passing an optical film according to an embodiment of the present invention will be described, taking as an example the case where the optical film is a raw film of a polarizing film.

FIG. 1 is a schematic diagram showing an example of a schematic configuration of a manufacturing facility for a polarizing plate manufactured from a raw film to which the paper passing method according to the present embodiment is applied. The arrows shown in FIG. 1 indicate the transport direction of each film.
In manufacturing the polarizing plate F using the manufacturing equipment shown in FIG. Then, it is dyed with a dichroic substance such as iodine or a dichroic dye, and uniaxially stretched. Then, by drying in an oven 3, a polarizing film F1 is obtained. The thickness of the polarizing film F1 (thickness of the polarizer) is not particularly limited, but is generally about 1 to 80 μm, preferably 1 to 20 μm.

Next, one side of the protective film F2 fed out from the feeding roller 5 is coated with an ultraviolet curable adhesive (hereinafter referred to as UV adhesive) using a gravure coater 6. Then, the protective film F2 coated with UV adhesive is pasted on both sides of the polarizing film F1 by the pasting roller 7. Next, the UV adhesive is cured using an ultraviolet irradiation device 8 and then dried in an oven 9. Finally, the surface protection film F3 fed out from the feeding roller 10 is bonded to one side of the polarizing film F1 with the protective film F2 bonded to both sides by the bonding roller 11, thereby obtaining the polarizing plate F. The obtained polarizing plate F is wound up by a winding roller 12.

FIG. 2 is a schematic diagram showing an example of a schematic configuration of the processing tank 2 shown in FIG. 1 and the conveyance equipment provided in the processing tank 2. FIG. 2 shows a state in which the original film F0 (including intermediate product films) is normally transported after passing.
As shown in FIG. 2, in this embodiment, a plurality of processing tanks are provided as the processing tank 2. As shown in FIG. The plurality of processing tanks shown in FIG. 2 are an upstream processing tank, a stretching processing tank 24, and a cleaning processing tank 25 in order from the upstream side (left side in FIG. 2) in the conveyance direction (right direction in FIG. 2) of the original film F0. be. The upstream processing tanks are a swelling processing tank 21, a dyeing processing tank 22, and a crosslinking processing tank 23 in this order from the upstream side in the conveyance direction of the original film F0.

The swelling treatment tank 21 is a treatment tank that performs a swelling treatment on the original film F0. As the treatment bath L in the swelling treatment tank 21, water is used, for example. By immersing the raw film F0 in the processing bath L in the swelling treatment tank 21, the raw film F0 can be cleaned, and by swelling the raw film F0, non-uniformity such as uneven dyeing can be prevented. You can expect the effect of Glycerin, potassium iodide, etc. may be added to the treatment bath L as appropriate. The temperature of the treatment bath L is preferably 20 to 45°C, more preferably 25 to 40°C. The immersion time of the original film F0 in the processing bath L during the production of the polarizing plate F is preferably 2 to 180 seconds, more preferably 10 to 150 seconds, and preferably 60 to 120 seconds. Particularly preferred. Note that the raw film F0 may be stretched in the treatment bath L in the swelling treatment tank 21, and the stretching ratio at this time is about 1.1 to 3.5 times, including expansion due to swelling.

The dyeing treatment tank 22 is a treatment tank that performs a dyeing treatment on the raw film F0 that has been subjected to the swelling treatment. As the treatment bath L in the dyeing treatment tank 22, for example, a solution in which a dichroic substance such as iodine is dissolved in a solvent is used. As the solvent, water is generally used, but an organic solvent compatible with water may be further added. By immersing the raw film F0 in the treatment bath L in the dyeing treatment tank 22, the dichroic substance is adsorbed onto the raw film F0. The temperature of the treatment bath L is preferably 5 to 42°C, more preferably 10 to 35°C. The immersion time of the original film F0 in the processing bath L during the production of the polarizing plate F is preferably 1 to 20 minutes, more preferably 2 to 10 minutes. Note that the raw film F0 may be stretched in the treatment bath L in the dyeing treatment tank 22, and the cumulative total stretching ratio at this time is about 1.1 to 4.0 times.

The crosslinking treatment tank 23 is a treatment tank that performs a crosslinking treatment on the raw film F0 that has been subjected to the dyeing treatment. As the treatment bath L in the crosslinking treatment tank 23, for example, a solution in which a crosslinking agent such as boric acid is dissolved in a solvent is used. As the solvent, water is generally used, but an organic solvent compatible with water may be further added. The raw film F0 is immersed in the treatment bath L in the crosslinking treatment tank 23, thereby crosslinking the raw film F0. The temperature of the treatment bath L is usually 20 to 70°C. The immersion time of the original film F0 in the processing bath L during the production of the polarizing plate F is usually 1 second to 15 minutes, preferably 5 seconds to 10 minutes. Note that the raw film F0 may be stretched in the treatment bath L in the crosslinking treatment tank 23, and the cumulative total stretching ratio at this time is about 1.1 to 4.0 times.

The stretching treatment tank 24 is a treatment tank that performs a stretching treatment on the original film F0 that has been subjected to a crosslinking treatment. As the treatment bath L in the stretching treatment tank 24, for example, a solution containing various metal salts or a compound of iodine, boron, or zinc is used. As the solvent, water, ethanol, or various organic solvents are appropriately used. With the original film F0 immersed in the treatment bath L in the stretching treatment tank 24, the original film F0 is stretched so that the cumulative total stretching ratio is about 2 to 7 times. The temperature of the treatment bath L is preferably 40 to 67°C, more preferably 50 to 62°C.

The cleaning treatment tank 25 is a treatment tank that performs a cleaning treatment on the original film F0 that has been subjected to the stretching treatment. As the treatment bath L in the cleaning treatment tank 25, for example, an aqueous solution containing an iodide such as sodium iodide or potassium iodide is used. By immersing the original film F0 in the processing bath L in the cleaning treatment tank 25, the original film F0 is washed (washed with water). The temperature of the treatment bath L is preferably 10 to 60°C, more preferably 15 to 40°C.

The paper passing method according to this embodiment is used in the conveying equipment provided in the processing tank 2 described above.
As shown in FIG. 2, the transport equipment provided in the processing tank 2 includes a plurality of transport rollers R11a to R15.
The conveyance roller R11a is a nip roller provided at the entrance of the swelling treatment tank 21, and is composed of a pair of rollers arranged vertically to face each other. The conveyance roller R11b is a nip roller provided at the exit of the swelling treatment tank 21 (at the entrance of the dyeing treatment tank 22), and is composed of a pair of rollers disposed opposite to each other in the horizontal direction (left-right direction in FIG. 2). The conveyance roller R12 is a nip roller provided at the exit of the dyeing treatment tank 22 (at the entrance of the crosslinking treatment tank 23), and is composed of a pair of rollers arranged horizontally to face each other. The conveyance roller R13 is a nip roller provided at the exit of the crosslinking treatment tank 23 (at the entrance of the stretching treatment tank 24), and is composed of a pair of rollers arranged horizontally to face each other. The conveyance roller R14 is a nip roller provided at the exit of the stretching tank 24 (at the entrance of the cleaning tank 25), and is composed of a pair of rollers arranged horizontally to face each other. The conveyance roller R15 is a nip roller provided at the outlet of the cleaning treatment tank 25, and is composed of a pair of rollers arranged to face each other in the horizontal direction. Hereinafter, the above-mentioned conveyance rollers R11a to R15 will be appropriately referred to as nip rollers R11a to R15. In this embodiment, one of the pair of rollers constituting the nip rollers R11a to R15 is a drive roller (which is driven by a motor to rotate and transport the original film F0 in the longitudinal direction by frictional force). The other roller is a driven roller (a roller that rotates freely and guides the original film F0 that is conveyed in the longitudinal direction).

The conveyance roller R2 is an elevating roller that can be moved up and down (movable in the vertical direction in FIG. 2) within each processing tank 2 (swelling processing tank 21 to cleaning processing tank 25). Hereinafter, the conveyance roller R2 will be appropriately referred to as a lifting roller R2. The elevating roller R2 is configured to be movable up and down by elevating means (not shown) such as a jack. In this embodiment, a pair of elevating rollers R2 are provided at positions upstream and downstream in the transport direction of the original film F0 of each processing tank 2.

FIG. 3 shows the procedure for passing the original film F0 through the pass line determined by the transport rollers R11a and R11b provided in the swelling treatment tank 21 shown in FIG. FIG. 3 is an explanatory diagram showing a procedure for immersing a film F0 in a processing bath L. Note that the pass line is an imaginary line determined by the position of each conveyance roller (conveyance rollers R11a, R11b) when performing the paper passing operation, and includes a common tangent line of two adjacent conveyance rollers used for the paper passing operation. .
First, as shown in FIG. 3(a), nip rollers R11a and R11b are opened. Specifically, one roller (for example, a driven roller) constituting the nip roller R11a is moved in the direction of arrow A. Similarly, one roller (for example, a driven roller) constituting the nip roller R11b is moved in the direction of arrow B.
Further, the lifting roller R2 provided in the swelling treatment tank 21 is raised above the liquid level of the treatment bath L in the swelling treatment tank 21. In this embodiment, the lifting roller R2 is raised above the nip rollers R11a and R11b, but the present invention is not limited to this. May be raised. Note that when the elevating roller R2 is raised below the nip rollers R11a and R11b, the original film F0 will be passed through the pass line determined by the transport rollers R11a, R2, and R11b in the procedure described later.

Next, as shown in FIG. 3(a), a person manually pulls the leading end of the original film F0 (the right end in FIG. 3(a)), and the lower roller constituting the nip roller R11a, The original film F0 is applied to the left roller constituting the nip roller R11b and the right roller constituting the nip roller R11b in this order, and the original film F0 is made to follow a pass line determined by the positions of these three rollers. This completes the paper passing operation up to the nip roller R11b. At this time, the drive roller (in this embodiment, the lower roller) that makes up the nip roller R11a and the drive roller (in this embodiment, the right roller) that makes up the nip roller R11b are driven and rotated to pass the paper. It is preferable.

When the paper passing operation is completed as described above, the nip roller R11a is closed. Specifically, one roller constituting the nip roller R11a is moved in the direction of arrow C shown in FIG. 3(b) and brought into contact with the original film F0.

Next, the lifting roller R2 is lowered below the liquid level of the processing bath L in the swelling processing tank 21 to immerse the original film F0 in the processing bath L. In this embodiment, when lowering the pair of lifting rollers R2 below the liquid level of the processing bath L, one of the pair of lifting rollers R2 is moved first as shown in FIG. 3(b). After lowering it in the direction of arrow D, the other lifting roller R2 is lowered in the direction of arrow E as shown in FIG. 3(c).

Finally, the nip roller R11b is closed. Specifically, one roller constituting the nip roller R11b is moved in the direction of the arrow F shown in FIG. 3(c) and brought into contact with the original film F0.

After the raw film F0 is immersed in the treatment bath L in the swelling treatment tank 21 as described above, the leading end of the raw film F0 is transferred between the transport roller R11b and the transport roller R12 provided in the dyeing treatment tank 22. The paper is passed through the pass line determined by the following, and after passing, the paper is immersed in the processing bath L in the dyeing processing tank 22. The procedure for passing and dipping the original film F0 in the dyeing treatment tank 22 is the same as in the case of the swelling treatment tank 21 described above. That is, first, the elevating roller R2 is lowered to immerse the original film F0 in the processing bath L, and then the conveying roller R12 is closed. In this embodiment, the same paper passing and dipping procedures as in the swelling treatment tank 21 are performed up to the crosslinking treatment tank 23.

According to the sheet passing method according to the present embodiment described above, after the original film F0 is immersed in the processing bath L in the processing tank 2 located upstream in the conveyance direction of the original film F0, the original film F0 is The original film F0 is passed through a conveyance roller provided in the processing tank 2 located downstream of F0 in the conveyance direction. That is, when the original film F0 is passed through the transport roller provided in the processing tank 2 (for example, the dyeing processing tank 22) located on the downstream side in the transport direction, the original film F0 is passed on the upstream side in the transport direction. Since the paper has been immersed in the processing bath L in the processing tank 2 (for example, the swelling processing tank 21) located there, it is softened, and the paper is passed through the transport rollers provided in the processing tank 2 located on the downstream side in the transport direction. When doing so, the original film F0 is less likely to be scratched or cut. As a result, appearance defects are less likely to occur in the original film F0.

Furthermore, according to the paper passing method according to the present embodiment, one of the pair of lifting rollers R2 is lowered first. Therefore, compared to the case where the pair of lifting rollers R2 are lowered at the same time, when only one lifting roller R2 is lowered (see FIG. 3(b)), the original film is pushed by the pair of lifting rollers R2. The inclination angle of F0 (the angle formed with the horizontal plane) increases. This makes it easier for the air bubbles B accumulated on the lower surface of the original film F0 to pass through the original film F0 and escape to the other lifting roller R2 (in the example shown in FIG. 3(b), the left lifting roller R2). Problems caused by air bubbles B in the treatment applied to the raw film F0 in the tank 2 are less likely to occur.

FIG. 4 is a diagram showing another example of the lifting roller R2 provided in the swelling treatment tank 21. The pair of lifting rollers R2 shown in FIG. 3 have the same vertical position after being lowered (see FIG. 3(c)). On the other hand, the pair of lifting rollers R2 shown in FIG. 4 have different vertical positions after being lowered. In the example shown in FIG. 4(a), the position after lowering of the elevating roller R2 on the downstream side in the conveying direction of the original film F0 (the right side in FIG. 4(a)) is on the upstream side in the conveying direction of the original film F0 (the The position is lower than the position after the lifting roller R2 has been lowered (on the left side of 4(a)). In the example shown in FIG. 4(b), the position of the lifting roller R2 on the upstream side in the transport direction after being lowered is lower than the position after lowering of the lifting roller R2 on the downstream side in the transport direction.
As shown in FIG. 4, when the vertical positions of the pair of lifting rollers R2 after being lowered are different from each other, the position of the pair of lifting rollers R2 after being lowered is lower than the position of the other lifting roller R2 after being lowered. It is preferable to lower it first. In the example shown in FIG. 4(a), it is preferable to lower the lifting roller R2 on the downstream side in the transport direction first, and in the example shown in FIG. 4(b), it is preferable to lower the lifting roller R2 on the upstream side in the transport direction first. This is preferable. It is better to first lower one of the lifting rollers R2, which will be in the lower position after lowering, than to lower the other lifting roller R2, which will be in the upper position after lowering, because the inclination angle of the original film F0 will be lower. This is because the bubbles B become larger and become easier to escape.

In this embodiment, an example has been described in which a pair of elevating rollers R2 are provided at the upstream and downstream positions in the transport direction of the original film F0 of each processing tank 2, but the present invention is not limited to this. Instead, it is also applicable to a case where each processing tank 2 is provided with three or more lifting rollers R2 in the conveying direction of the original film F0.
When three or more lifting rollers R2 are provided, it is preferable to lower all the lifting rollers R2 one after another rather than lowering them all at the same time. In addition, in the case where three or more lifting rollers R2 are provided, and when there are lifting rollers R2 whose positions in the vertical direction after lowering are different from each other, the lifting roller R2 whose position after lowering is the lowest is present. is preferably lowered first.
Regarding the fact that the number of elevating rollers R2 provided in each of the above-mentioned processing tanks 2 may be three or more, and the preferable order in which the elevating rollers R2 are lowered, it is noted that the upstream processing tanks (swelling processing tank 21, dyeing processing tank 22 and The same applies not only to the crosslinking treatment tank 23) but also to the stretching treatment tank 24 and the cleaning treatment tank 25.

Hereinafter, the procedure of paper passing and dipping in the stretching treatment tank 24 and the cleaning treatment tank 25 using the paper passing method according to the present embodiment will be explained.

FIG. 5 is an explanatory diagram showing the procedure of paper passing and dipping in the stretching bath 24 and the cleaning bath 25 using the paper passing method according to the present embodiment.
FIG. 5A shows a state in which paper passing and dipping in the upstream processing tanks (swelling processing tank 21, dyeing processing tank 22, and crosslinking processing tank 23) have been completed according to the above-described procedure. Specifically, the work of passing the original film F0 through the transport rollers R11a to R13 provided in the swelling treatment tank 21, the dyeing treatment tank 22, and the crosslinking treatment tank 23, and This shows a state in which the original film F0 has been immersed in the treatment bath L in the crosslinking treatment tank 23.
In this embodiment, the leading end of the original film F0 that has been immersed in the processing bath L in the upstream processing tank shown in FIG. The entire portion or a portion thereof from the roller R11a to the conveying roller R13 provided in the crosslinking treatment tank 23 is cut out. Specifically, the leading end of the original film F0 that has been immersed in the processing bath L in the upstream processing tank is wound up by hand or with a portable take-up roller (not shown), and after this leading end is rolled up. Cut the end and collect the tip.

Next, as shown in FIG. 5B, the original film F0 following the cut end portion is passed through transport rollers R14 and R15 provided in the stretching tank 24 and the cleaning tank 25. Specifically, the lifting roller R2 provided in the stretching tank 24 is raised above the liquid level of the processing bath L in the stretching tank 24, and the lifting roller R2 provided in the cleaning tank 25 is cleaned. The raw film F0 is raised above the liquid level of the processing bath L in the processing tank 25 without immersing it in the processing bath L in the stretching processing tank 24 and the processing bath L in the cleaning processing tank 25. The paper is passed through transport rollers R14 and R15 provided in the stretching tank 24 and the cleaning tank 25.

Next, as shown in FIG. 5(c), the lifting roller R2 provided in the cleaning tank 25 is lowered below the liquid level of the processing bath L in the cleaning tank 25 to clean the original film F0. It is immersed in the processing bath L in the processing tank 25. After this, as shown in FIG. 5(d), the nip roller R15 is closed.

Finally, as shown in FIG. 5(d), the lifting roller R2 provided in the stretching tank 24 is lowered below the liquid level of the processing bath L in the stretching tank 24 to stretch the original film F0. It is immersed in the processing bath L in the processing tank 24. After this, the nip roller R14 is closed. Since the processing bath L in the stretching bath 24 is generally at a higher temperature than the other processing baths 2, if the original film F0 is immersed in the treatment bath L, there is a risk that it will be cut or melted. For this reason, it is preferable to immerse the nip rollers R13 and R15 in a closed state (with the original film F0 stretched).
After performing the above procedure, the paper is subsequently passed through a conveyance roller (not shown) located on the downstream side in the conveyance direction.

The raw film F0 immersed in the processing bath L in the upstream processing tanks (swelling processing tank 21, dyeing processing tank 22, and crosslinking processing tank 23) may become too soft due to repeated paper passing and dipping. On the other hand, as described above, the treatment bath L in the stretching bath 24 is generally at a higher temperature than the other treatment baths 2. Therefore, if the optical film that has become too softened is immersed in the treatment bath L of the stretching treatment tank 24, there is a risk that the original film F0 will be cut or melted.
According to the paper passing method according to the present embodiment, after cutting off the leading end of the original film F0 that has been immersed in the processing bath L in the upstream processing tank, the following original film F0 is attached to the cut leading end. The paper passes through transport rollers R14 and R15 provided in the stretching tank 24 and the cleaning tank 25. Since the sheet passing work to the transport roller provided in the upstream processing tank (sheet passing work up to transport roller R13) has been completed, the leading end of the original film F0 is removed by hand or with a portable take-up roller. By winding up, the original film F0 following the leading end is immersed in the processing bath L in the upstream processing tank. For this reason, the original film F0 following the leading edge is softened, and when it passes through the transport rollers R14 and R15 provided in the stretching treatment tank 24 and the cleaning treatment tank 25, the original film F0 is scratched or cut. It becomes difficult to occur. Also, compared to the time that the leading end of the cut original film F0 was immersed in the processing bath L in the upstream processing tank, the length of the original film F0 following the leading end was immersed in the processing bath L in the upstream processing tank. (The immersion time for the leading edge is longer by the time required for the sheet to pass through the conveyance roller provided in the upstream processing tank), so the original film F0 following the leading edge is The softening of the film does not proceed excessively, and the risk of it being cut or melted in the treatment bath L of the stretching treatment tank 24 can be suppressed.

Further, according to the paper passing method according to the present embodiment, the original film F0 is first immersed in the processing bath L in the cleaning processing tank 25 and then in the processing bath L in the stretching processing tank 24. become. In this way, by immersing the body in the treatment bath L in the cleaning treatment tank 25 before the treatment bath L in the stretching treatment tank 24, the high-temperature treatment bath in the stretching treatment tank 24 can be immersed, compared to the case where the order is reversed. The time for immersion in L is shortened, and the possibility that the original film F0 is cut or melted can be further suppressed.

In the embodiment described above, the optical film is the original film F0 of the polarizing film F1, but the present invention is not limited to this, and can be applied to various other optical films. Applicable.

2... Processing tank 21... Swelling processing tank 22... Dyeing processing tank 23... Crosslinking processing tank 24... Stretching processing tank 25... Washing processing tank F0... Optical film (original film) film)
F1...Polarizing film L...Processing bath R11a, R11b, R12, R13, R14, R15...Conveyance roller (nip roller)
R2... Conveyance roller (elevating roller)

Claims (6)

A method for passing an optical film through a pass line of the transport equipment in an optical film manufacturing equipment including a transport equipment having a plurality of transport rollers and a plurality of processing tanks, the method comprising:
After the optical film is immersed in a processing bath in a processing tank located upstream in the transport direction of the optical film, the optical film is transferred to a transport roller provided in a processing tank located downstream in the transport direction of the optical film. pass through the paper ,
The manufacturing equipment includes, as the plurality of processing tanks, sequentially from the downstream side in the transport direction of the optical film, a cleaning processing tank that performs a cleaning process on the optical film, a stretching processing tank that performs a stretching process on the optical film, and the an upstream treatment tank for subjecting the optical film to a predetermined treatment;
After cutting off the tip of the optical film that has been immersed in the processing bath in the upstream processing tank, the optical film following the cut tip is placed in the stretching processing tank and the cleaning processing tank. Pass the paper through the transport roller,
Among the conveyance rollers provided in the stretching treatment tank, an elevating roller, which is a conveyance roller that can be raised and lowered in the stretching treatment tank, is raised above the liquid level of the processing bath in the stretching treatment tank, and the cleaning Among the transport rollers provided in the processing tank, the lifting roller, which is a transport roller that can be raised and lowered in the cleaning processing tank, is raised above the liquid level of the processing bath in the cleaning processing tank, and the optical After passing the film through the conveying rollers provided in the stretching tank and the cleaning tank without immersing the film in the processing bath in the stretching tank and the cleaning tank, the film is placed in the cleaning tank. The optical film is immersed in the processing bath in the cleaning processing tank by lowering the provided lifting roller below the liquid level of the processing bath in the cleaning processing tank, and then A method for passing an optical film, the method comprising lowering an elevating roller below the liquid level of a processing bath in the stretching tank to immerse the optical film in the processing bath in the stretching tank .
The pass line refers to a conveyance path of the optical film determined by the position of the conveyance roller, and the paper passing means that a person manually pulls the leading end of the optical film to cause the optical film to pass through the conveyance roller. It means the operation of applying the above-mentioned optical film along the above-mentioned pass line. Among the transport rollers provided in the processing tank located upstream in the transport direction of the optical film, the lifting roller, which is a transport roller that can be raised and lowered within the processing tank, is placed above the liquid level of the processing bath in the processing tank. After the optical film is passed through the conveying roller in a state where the optical film is raised to a height of 100.degree. C., the elevating roller is lowered below the liquid level of the processing bath to immerse the optical film in the processing bath. 1. The method for passing the optical film according to 1. The upstream treatment tank includes, in order from the upstream side in the transport direction of the optical film, a swelling treatment tank that applies a swelling treatment to the optical film, a dyeing treatment tank that applies a dyeing treatment to the optical film, and a crosslinking treatment to the optical film. The method for passing an optical film according to claim 1 or 2, which is a crosslinking treatment tank. A plurality of elevating rollers are provided as the elevating rollers in the transporting direction of the optical film in a processing tank located upstream in the transporting direction of the optical film, and the plurality of elevating rollers are lowered below the liquid level of the processing bath. The method for passing an optical film according to claim 2 or 3 , wherein the optical film is lowered in order when the film is moved. 5. The optical film according to claim 4 , wherein among the plurality of lifting rollers, there are lifting rollers having different positions in the vertical direction after lowering, and the lifting roller whose position after lowering is the lowest is lowered first. How to pass paper. The method for passing an optical film according to any one of claims 1 to 5 , wherein the optical film is an original film of a polarizing film.

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