JP2021033086A - Drying device and drying method of polarization film - Google Patents

Abstract

To provide a drying device of a polarization film capable of preventing a damage on an edge part of a polarization film.SOLUTION: A drying device is configured to blow a warm wind to a long belt-like polarization film during a process of conveying the polarization film in a longer direction. The drying device includes: a warm wind duct 5 having a warm wind blowout part 52 arranged opposing to a surface of the polarization film 2Y; and a coating sheet 7 covering an area corresponding to a width direction end part of the polarization film 2Y in the warm wind blowout part 52.SELECTED DRAWING: Figure 17

Description

The present invention relates to a polarizing film drying apparatus containing a polarizer and a method for drying the same.

Conventionally, a polarizing film containing a polarizing element has been used as a constituent material for a liquid crystal display device, polarized sunglasses, and the like. Examples of the polarizing film include a laminate in which a protective film is laminated on a polarizing element.
A polarizing film made of such a laminate can be obtained by manufacturing a polarizing element and then attaching a protective film to the polarizing element using an adhesive.
For example, in Patent Document 1, a long strip-shaped polarizing element and a protective film (cellulose acetate-based resin film) are bonded together using an adhesive to form a polarizing film (laminated body), and then the polarizing film is dried in an oven. It is disclosed that it is dried using.
Such a drying oven is a method of blowing warm air onto the laminated body while transporting the long strip-shaped laminated body. A drying oven of a type that blows warm air usually has a hot air duct in which a hot air blowing portion for blowing warm air is formed on the surface of the polarizing film.

Japanese Unexamined Patent Publication No. 2013-205721

However, when the polarizing film containing the polarizing element is dried by blowing warm air, the widthwise end portion of the polarizing film may be curled.
When the polarizing film having a curled end is conveyed and dried using a warm air duct during drying in this way, the curled end may come into contact with the hot air blowing portion. When the edge of the polarizing film comes into contact with the hot air blowing portion, the edge of the polarizing film may be scraped off by the warm air blowing portion and damaged. Further, when the edge portion of the polarizing film is scraped off, film slag is generated, and the slag may adhere to the edge portion of the polarizing film. Such scratches on the edges and adhesion of foreign substances such as film slag reduce the yield of the polarizing film, and improvement thereof is required.

Also, depending on the production lot, polarizing films having various widths are dried. Since the position of the end portion in the width direction is different between the polarizing film having a relatively large width and the polarizing film having a relatively small width, the location where it comes into contact with the warm air blowing portion is also different.

A first object of the present invention is to provide a polarizing film drying device and a drying method capable of preventing scratches on the edges of the polarizing film.
A second object of the present invention is to provide a polarizing film drying device and a drying method capable of preventing scratches on the edges of the polarizing films even when the polarizing films having different widths are dried.

The polarizing film drying device of the present invention is a drying device that blows warm air onto the polarizing film in the process of transporting the long strip-shaped polarizing film in the longitudinal direction, and the warm air blowing device is arranged to face the surface of the polarizing film. It has a warm air duct having a protruding portion and a covering sheet covering a region of the warm air blowing portion corresponding to the widthwise end portion of the polarizing film.

In the preferred polarizing film drying device of the present invention, one end of the covering sheet is fixed to one side of the warm air blowing portion of the hot air duct, and the opposite end of the covering sheet is a free end. A rod member is attached to the opposite end of the covering sheet, and a locking portion capable of locking the rod member is provided on the opposite side of the hot air blowing portion of the hot air duct. By locking the rod member to the locking portion, the covering sheet covers the region.
In the preferred polarizing film drying apparatus of the present invention, the coating sheet covers the region in a tensioned state.
The preferred polarizing film drying apparatus of the present invention has two or more of the coating sheets, the first coating sheet covers the region corresponding to the widthwise end of the first polarizing film, and the second coating sheet is the said. It covers the widthwise end of the second polarizing film, which is narrower than the first polarizing film.
The preferred polarizing film drying apparatus of the present invention is composed of a pair of left and right covering sheets so as to cover the regions corresponding to both ends in the width direction of the polarizing film.
In the preferred polarizing film drying apparatus of the present invention, the coating sheet includes a polyimide resin sheet.

According to another aspect of the present invention, there is provided a method for drying a polarizing film.
The method for drying a polarizing film of the present invention has a warm air blowing portion arranged to face the surface of the polarizing film in the drying method for drying the polarizing film in the process of transporting the long strip-shaped polarizing film in the longitudinal direction. A step of covering the region of the hot air duct corresponding to the widthwise end of the polarizing film in the hot air blowing portion with a coating sheet, and blowing warm air from the hot air duct covered with the coating sheet. The polarizing film is dried by transporting the polarizing film in the longitudinal direction.

In a preferred method for drying a polarizing film of the present invention, the warm air duct is provided with two or more of the covering sheets, and depending on the polarizing films having different widths, the two or more covering sheets can be selected. The area is covered with a coating sheet of choice.

According to the drying apparatus and drying method of the present invention, the polarizing film can be dried while preventing the edges of the polarizing film from being scratched.
Further, according to the preferred drying apparatus and drying method of the present invention, polarizing films having different widths can be dried while preventing scratches on the edges.

A partially omitted plan view of the polarizing film of the present invention. A cross-sectional view of a polarizing film (basic polarizing film) according to one embodiment (cross-sectional view taken along line II-II of FIG. 1). Sectional drawing of the polarizing film (basic polarizing film) which concerns on another embodiment. FIG. 5 is a cross-sectional view of a polarizing film (laminated polarizing film) according to still another embodiment. FIG. 5 is a cross-sectional view of a polarizing film (laminated polarizing film) according to still another embodiment. The schematic front view which shows the manufacturing apparatus of a polarizing film. The front view which shows the 1st warm air duct and the 2nd warm air duct in the state before covering the hot air blowing part by a covering sheet. The bottom view of the first warm air duct seen from the direction of arrow VIII of FIG. The left side view of the first warm air duct seen from the direction of the arrow IX of FIG. The right side view of the first warm air duct seen from the direction of arrow X of FIG. Top view of the first warm air duct seen from the direction of arrow XI in FIG. 7. FIG. 11 is an enlarged cross-sectional view taken along the line XII-XII of FIG. FIG. 11 is an enlarged cross-sectional view taken along the line XIII-XIII of FIG. Top view of the second warm air duct as seen from the direction of arrow XIV in FIG. The front view which shows the procedure of covering the hot air blowing part of the 1st hot air duct with a covering sheet. An enlarged cross-sectional view showing a state in which the hot air blowing portion of the first hot air duct is covered with the first covering sheet. Bottom view seen from the direction of arrow XVII in FIG. An enlarged cross-sectional view showing a state in which the hot air blowing portion of the second hot air duct is covered with the first covering sheet. Top view seen from the direction of arrow XIX in FIG. An enlarged cross-sectional view showing a state in which the hot air blowing portion of the first hot air duct is covered with the second covering sheet. An enlarged cross-sectional view showing a state in which the hot air blowing portion of the first hot air duct is covered with the third covering sheet.

In the present specification, the numerical range represented by "lower limit value X to upper limit value Y" means a lower limit value X or more and an upper limit value Y or less. When a plurality of the numerical values are described separately, it is possible to select an arbitrary lower limit value and an arbitrary upper limit value and set "arbitrary lower limit value to arbitrary upper limit value".
In the present specification, "first" and "second" may be added to the beginning of terms, but the first and the like are added only for distinguishing the terms, and the order and superiority or inferiority thereof. It has no special meaning such as.

[Polarizer and laminated polarizing film]
FIG. 1 is a partially omitted plan view of the polarizing film 1 of the present invention.
The polarizing film 1 obtained by the drying method (manufacturing method) of the present invention has a long strip shape. This long strip-shaped polarizing film is cut into an appropriate shape and used for various purposes.
In the present invention, the polarizing film to be dried (manufactured) is a film containing a polarizer. Here, the polarizer is an optical element having a property of transmitting light (polarized light) vibrating in only one specific direction and blocking light vibrating in the other direction (this property is a polarization characteristic). Say.
The polarizing film may contain a polarizer. The polarizing film of the present invention is conceptually polarized with an arbitrary film such as a polarizer itself, a film in which a polarizer and a support film are laminated, a film in which an arbitrary film such as a protective film is laminated, and an arbitrary film such as a protective film. A film in which a child and a support film are laminated, and the like are included.

FIG. 2 is a cross-sectional view of the polarizing film 1 cut along the line II-II of FIG.
With reference to FIG. 2, the polarizing film 1 according to one embodiment includes a support film 11 and a polarizer 12 laminated on one surface of the support film. The polarizer 12 is composed of a hydrophilic polymer layer dyed with a dichroic substance. Such a hydrophilic polymer layer has polarization properties.
FIG. 3 is a cross-sectional view of the polarizing film 1 according to another embodiment. This cross-sectional view is also a cross-sectional view of the polarizing film 1 of another embodiment cut at the same location as the line II-II of FIG.
With reference to FIG. 3, the polarizing film 1 of another embodiment is composed of the polarizer 13 itself. The polarizer 13 is composed of a hydrophilic polymer film dyed with a dichroic substance. Such hydrophilic polymer films have polarization properties.
Hereinafter, the polarizing film 1 composed of the support film 11 and the polarizing element 12 shown in FIG. 2 and the polarizing film 1 composed of only the polarizing element 13 shown in FIG. 3 are collectively referred to as “basic polarizing film 1”.

Further, it may be a polarizing film in which one or two or more suitable arbitrary films are laminated on the basic polarizing film 1. Hereinafter, the arbitrary film is referred to as an "arbitrary film", and a polarizing film obtained by laminating an arbitrary film on the basic polarizing film 1 is collectively referred to as a "laminated polarizing film".
4 and 5 are cross-sectional views of some laminated polarizing films 2.
With reference to FIG. 4, the laminated polarizing film 2 according to one embodiment has a basic polarizing film 1 having a support film 11 and a polarizer 12 and an adhesive layer 211 on the polarizing element 12 of the basic polarizing film 1. The first optional film 21 and the laminated film 21 are provided.
With reference to FIG. 5, the laminated polarizing film 2 according to another embodiment is laminated on one surface of the basic polarizing film 1 composed of only the polarizer 13 and the basic polarizing film 1 via an adhesive layer 211. It has a first optional film 21 and a second optional film 22 laminated on the opposite surface of the basic polarizing film 1 via an adhesive layer 221.

<Arbitrary film>
Examples of the optional film include a protective film, a retardation film, a brightness improving film, and a transparent conductive film. The arbitrary film to be laminated on the basic polarizing film 1 is appropriately selected from these.
For example, a protective film is used as the first optional film 21. For example, a protective film is used as the second optional film 22. For example, as the third optional film 23, a protective film or a retardation film is used.
The protective film is a film for protecting the polarizer. As will be described later, the protective film is laminated on the basic polarizing film after preparing the basic polarizing film.
The protective film is a film used for the purpose of protecting a polarizer or the like, which is a protected body, from scratches and dirt. Examples of the protective film include olefin resins such as polyethylene and polypropylene; ester resins such as polyethylene terephthalate; amide resins such as nylon 6; vinyl polymers such as polyvinyl chloride and vinyl chloride-vinyl acetate copolymer; Examples thereof include films made of cellulose-based resins such as cellulose triacetate and cellulose diacetate; acrylic resins such as polymethylmethacrylate; styrene-based resins; carbonate-based resins; polyarylate-based resins; and imide-based resins.
The retardation film is an optical film that exhibits optical anisotropy. Examples of the retardation film include anisotropic films such as 1 / 2λ plate and 1 / 4λ plate.
The brightness improving film is an optical film that transmits only specific polarized light and reflects other polarized light.

<Adhesive layer>
The adhesive layer is a solidifying layer of an adhesive, which is a layer interposed between two films and adhering the two films.
The adhesive layer is composed of, for example, an active energy ray-curable adhesive such as an ultraviolet curable adhesive, a solvent-volatile adhesive, and the like.

[Manufacturing equipment for basic polarizing film and laminated polarizing film]
The manufacturing apparatus of the present invention has a basic polarizing film production zone for producing a long strip-shaped basic polarizing film and a laminated polarizing film production zone for producing a long strip-shaped laminated polarizing film.
In the basic polarizing film production zone, a basic polarizing film is produced by wet-treating a long strip-shaped raw film. The basic polarizing film production zone is preferably a method in which a series of steps from wet-treating the raw film to obtaining a basic polarizing film by drying it is performed on one production line.
In the laminated polarizing film production zone, a laminated polarizing film is produced by laminating an arbitrary long strip-shaped film on a long strip-shaped basic polarizing film. The laminated polarizing film production zone is a method in which a series of steps from laminating an arbitrary film on a basic polarizing film via an adhesive and drying the film to obtain a laminated polarizing film is performed on one production line. preferable.

Further, in the manufacturing apparatus of the present invention, the basic polarizing film manufacturing zone and the laminated polarizing film manufacturing zone may be independent of each other, or the basic polarizing film manufacturing zone and the laminated polarizing film manufacturing zone are combined into one manufacturing zone. It may be a method arranged on a line.
Specifically, in the production of a laminated polarizing film, (a) after producing a basic polarizing film, the basic polarizing film is once wound on a roll, the basic polarizing film wound on the roll is unwound, and an arbitrary film is laminated and bonded. The method may be used, or (b) after manufacturing the basic polarizing film, an arbitrary film may be laminated and adhered to the basic polarizing film on one production line. From the viewpoint of manufacturing efficiency, the method (b) described above is preferable.
The manufacturing apparatus according to the method (b) is a method in which a basic polarizing film manufacturing zone and a laminated polarizing film manufacturing zone are arranged in a series on one manufacturing line (until obtaining a laminated polarizing film from the basic polarizing film). This is a method in which a series of processes is performed on one production line).

FIG. 6 shows a preferable configuration example of the apparatus 10 for manufacturing the polarizing film (basic polarizing film and laminated polarizing film) of the method (b).
With reference to FIG. 6, the manufacturing apparatus 10 includes a transport device 101 for transporting each film such as the original film Y, the basic polarizing film 1Y, the laminated polarizing film 2Y, and the arbitrary films 21Y and 22Y, and the basic polarizing film manufacturing zone. It has at least 3 and a laminated polarizing film manufacturing zone 4 for adhering at least one film to the basic polarizing film 1Y. The transport device 101 includes various rollers such as guide rollers.
The basic polarizing film manufacturing zone 3 includes a wet processing device 31 for wet-treating the original film Y and a drying device 32 for drying the basic polarizing film 1Y.
The laminated polarizing film manufacturing zone 4 is a laminated polarizing film in which an arbitrary film is bonded to the basic polarizing film 1Y obtained by the basic polarizing film manufacturing zone 3 by using an adhesive, and a laminated polarizing film in which the optional film is bonded. It has a drying device 42 for drying 2Y.

The drying device 32 of the basic polarizing film manufacturing zone 3 blows warm air onto the basic polarizing film 1Y in the process of transporting the long strip-shaped basic polarizing film 1Y (polarizing film) in the longitudinal direction.
The drying device 42 of the laminated polarizing film manufacturing zone 4 blows warm air onto the laminated polarizing film 2Y in the process of transporting the long strip-shaped laminated polarizing film 2Y (polarizing film) in the longitudinal direction.
In the present invention, as a drying device that blows warm air onto the polarizing film in the process of transporting the long strip-shaped polarizing film in the longitudinal direction, the widthwise end of the polarizing film in the hot air blowing portion of the hot air duct. It is characterized by using an apparatus having a covering sheet covering the area corresponding to the above.
The drying device having such a coating sheet may be applied to the drying device 32 of the basic polarizing film manufacturing zone 3 and / or may be applied to the drying device 42 of the laminated polarizing film manufacturing zone 4. ..
In the configuration example of FIG. 6, the case where the characteristic drying device (drying device having a coating sheet) of the present invention is adopted as the drying device 42 of the laminated polarizing film manufacturing zone 4 is illustrated.

<Basic polarizing film production zone>
The basic polarizing film production zone 3 includes a wet processing device 31 that obtains a basic polarizing film 1Y by wet-treating the original film Y, and a drying device 32 that dries the basic polarizing film 1Y obtained by the wet treatment. Have.
The wet processing apparatus 31 can adopt a conventionally known structure.
For example, the wet treatment apparatus 31 includes a swelling treatment tank 311, a dyeing treatment tank 312, a cross-linking treatment tank 313, a stretching treatment tank 314, and a cleaning treatment tank 315 in this order from the upstream side. The wet treatment apparatus 31 is not limited to the above configuration, and may not have, for example, the swelling treatment tank 311 or the stretching treatment tank 314. When the stretch treatment tank 314 is not provided, the stretch treatment is performed on the film raw fabric Y in a tank such as the dyeing treatment tank 312. Further, the wet treatment apparatus 31 may have another treatment tank such as an adjustment treatment tank.
In the present specification, the downstream side refers to the film transporting direction side (the film traveling direction side), and the upstream side refers to the opposite side (the side opposite to the film transporting direction).
The untreated film raw fabric Y is transported to the downstream side of the swelling treatment tank 311 or the like by a transport device 101 provided with a guide roll or the like. The white arrows in FIG. 6 indicate the traveling direction (conveying direction) of the film.

The original film Y has a long strip shape. In the present specification, the long strip shape refers to a rectangular shape whose length in the longitudinal direction is sufficiently larger than the length in the lateral direction (direction orthogonal to the longitudinal direction). The length of the long strip in the longitudinal direction is, for example, 10 m or more, preferably 50 m or more.
As the original film Y, a long strip-shaped film containing a hydrophilic polymer is used.
As the original film Y, for example, a laminate composed of a long strip-shaped support film and a hydrophilic polymer layer laminated on one surface of the support film, or a hydrophilic polymer film can be used. When the laminate is used as the original film Y, the basic polarizing film shown in FIG. 2 can be obtained. When the hydrophilic polymer film is used as the original film Y, the basic polarizing film shown in FIG. 3 can be obtained.

As the original film Y, a conventionally known untreated film is used.
Briefly, the hydrophilic polymer layer of the laminate can be formed by applying a coating liquid containing a hydrophilic polymer to one surface of a support film and drying the coating liquid. As the support film, a colorless and transparent resin film can be used, and for example, an ester resin film such as a polyethylene terephthalate resin can be used.
Examples of the hydrophilic polymer include polyvinyl alcohol (PVA) -based resin and ethylene-vinyl alcohol copolymer.
The hydrophilic polymer film is obtained by forming a hydrophilic polymer into a film. Examples of the hydrophilic polymer include PVA-based resins and ethylene-vinyl alcohol copolymers, as described above.

The swelling treatment tank 311 is a treatment tank containing a swelling liquid. The swelling liquid swells the original film Y. As the swelling liquid, for example, water or an aqueous solution containing an iodine compound such as potassium iodide can be used.
The dyeing treatment tank 312 is a treatment tank containing a dyeing solution. The dyeing solution stains the hydrophilic polymer of the original film Y. As the staining solution, for example, an aqueous solution containing a dichroic substance can be used, and preferably an aqueous solution containing a dichroic substance and an iodine compound such as potassium iodide can be used. Examples of the dichroic substance include iodine and organic dyes.
The cross-linking treatment tank 313 is a treatment tank containing a cross-linking liquid. The cross-linking solution cross-links the dyed film raw fabric Y. As the cross-linking solution, for example, an aqueous solution containing a boron compound such as boric acid can be used, and preferably an aqueous solution containing an iodine compound such as a boron compound and potassium iodide can be used.
The stretching treatment tank 314 is a treatment tank containing a stretching liquid. As the stretching liquid, for example, an aqueous solution containing a boron compound can be used, and preferably an aqueous solution containing an iodine compound such as a boron compound and potassium iodide can be used. By dyeing and stretching, the original film Y becomes the basic polarizing film 1Y.
The cleaning treatment tank 315 is a treatment tank containing a cleaning liquid. The cleaning liquid cleans the basic polarizing film 1Y (film raw fabric Y after dyeing and stretching). As the cleaning liquid, for example, water or an aqueous solution containing an iodine compound such as potassium iodide can be used.
If necessary, on the downstream side of the cleaning treatment tank 315, there is a shower portion 316 that sprays the cleaning liquid onto the basic polarizing film 1Y drawn from the cleaning treatment tank 315, and a blower portion 317 (liquid) that removes the cleaning liquid adhering to the film. A cut part) is provided.

The drying device 32 of the basic polarizing film manufacturing zone 3 is provided on the downstream side of the cleaning treatment tank 315. The drying device 32 is provided for drying the basic polarizing film 1Y after the cleaning treatment. One drying device 32 may be provided, or two or more drying devices 32 may be provided side by side in the transport direction of the basic polarizing film 1Y. The drying device 32 is preferably, for example, a method in which warm air is blown onto the basic polarizing film 1Y to dry the film. Such a drying device 32 has, for example, a chamber 321 and a hot air duct (not shown) having a hot air blowing portion for blowing hot air, and the hot air duct is arranged in the chamber 321. ..

<Laminated polarizing film production zone>
The laminated polarizing film manufacturing zone 4 includes a laminating device 41 in which an arbitrary film is bonded to the basic polarizing film 1Y obtained in the basic polarizing film manufacturing zone 3 using an adhesive, and a laminated polarizing film 2Y in which the optional film is bonded. It has a drying device 42 and a drying device 42 for drying the film.
The stacking device 41 can adopt a conventionally known structure. To briefly explain the laminating device 41 with reference to FIG. 6, the laminating device 41 includes adhesive coating portions 421 and 413 for applying an adhesive to the first and second arbitrary films 21Y and 22Y, and basic polarization. It has a bonding portion 414 for bonding the film 1Y and an arbitrary film. An appropriate coater can be adopted for the adhesive coating portion, and for example, a gravure roll is used as shown in the figure. For the bonding portion 414, for example, a nip roll is used.
When the adhesive is an active energy ray-curable type, the active energy ray irradiation device 415 is arranged after the bonded portion.
The laminating device 41 of the illustrated example is a double-sided laminating type in which the first arbitrary film 21Y and the second arbitrary film 22Y are laminated on one side and the opposite side of the basic polarizing film 1Y. When such a laminating device 41 is used, for example, a laminated polarizing film as shown in FIG. 5 can be obtained. The laminating device 41 may be a one-sided laminating type in which an arbitrary film is laminated only on one side of the basic polarizing film 1Y. When such a one-sided laminated type laminating device 41 is used, for example, a laminated polarizing film as shown in FIG. 4 can be obtained.
After a surface protective film (not shown) is attached to the obtained laminated polarizing film, the laminated polarizing film is wound up.

[Drying device of the present invention]
The drying device 42 of the laminated polarizing film manufacturing zone 4 is provided on the downstream side of the laminated device 41. The drying device 42 is provided for drying the laminated polarizing film 2Y (a laminated body in which a basic polarizing film and an arbitrary film are bonded together). One drying device 42 may be provided, or two or more drying devices 42 may be provided side by side in the transport direction of the laminated polarizing film 2Y.
In the illustrated example, the laminated polarizing film 2Y is conveyed substantially horizontally, and two drying devices 42 are arranged in the transfer process.
The drying device 42 has a warm air duct 5 having a hot air blowing portion arranged so as to face the surface of the basic polarizing film 1Y, and a region of the warm air blowing portion corresponding to the widthwise end portion of the laminated polarizing film 2Y. It has a covering sheet 7 and, if necessary, an additional chamber 421.
The chamber 421 is a case that surrounds the outside of the warm air duct 5 provided with the covering sheet 7. The hot air duct 5 is housed in the chamber 421 in a sealed manner.

As the coating sheet 7, a resin sheet that is flexible and has excellent smoothness is used. The material of the resin sheet is not particularly limited, and is a polyester resin such as polyethylene terephthalate; an olefin resin such as polypropylene; a styrene resin such as polystyrene or a styrene-butadiene copolymer; a cyclic olefin resin; a vinyl chloride resin; Examples thereof include one kind selected from vinyl chloride-based copolymers; polyamide-based resins; polyimide-based resins; polycarbonate-based resins; fluororesins and the like, or a mixture of two or more kinds.
Since it is used for the hot air duct 5, the covering sheet 7 is preferably a resin sheet having excellent heat resistance. As the resin sheet having excellent heat resistance, for example, a resin having a glass transition temperature of 100 ° C. or higher is preferable, and a resin having a glass transition temperature of 200 ° C. or higher is more preferable. Fluororesin sheet and the like can be mentioned. Of these, a polyimide resin sheet having a glass transition temperature of 216 ° C. is preferable. When a polypropylene sheet having a glass transition temperature of around 0 ° C. or a polyethylene terephthalate sheet having a glass transition temperature of less than 100 ° C. is used, the sheet may be stretched or wrinkled due to heat.
The thickness of the covering sheet 7 is not particularly limited, and is, for example, 50 μm to 200 μm.

The covering sheet 7 is formed in a band shape.
The width of the covering sheet 7 is not particularly limited, but if it is too small, the covering width of the region corresponding to the widthwise end of the laminated polarizing film 2Y (polarizing film) becomes too small, and if it is too large, the warm air blowing portion is widened. It blocks up and the amount of warm air blown out is too limited. From this point of view, the width W7 of the covering sheet 7 is preferably 30 mm to 150 mm, more preferably 50 mm to 100 mm. In addition, in this specification, a width means a length in a width direction.
For the strip shape and width W7 of the covering sheet 7, refer to FIG. 17, for example.

The warm air duct 5 provided with the covering sheet 7 is arranged on both surfaces (one side and the opposite side) of the laminated polarizing film 2Y, respectively. In the present specification, the warm air duct 5 arranged on one side of the laminated polarizing film 2Y (polarizing film) is referred to as "first hot air duct 5A", and is located on the opposite side of the laminated polarizing film 2Y (polarizing film). The arranged hot air duct 5 is referred to as "second hot air duct 5B", and the whole is collectively referred to as "warm air duct 5".
The first hot air duct 5A and the second hot air duct 5B may be independently provided by only one unit, but preferably two or more units are arranged side by side in the longitudinal direction of the laminated polarizing film 2Y, and more preferably, they are laminated. Three or more polarizing films 2Y are arranged side by side in the longitudinal direction. There is no particular upper limit on the number of the first hot air duct 5A and the second hot air duct 5B, but each of them is independently, for example, 15 or less, preferably 12 or less.
In the illustrated example, a case where three first hot air ducts 5A and three second hot air ducts 5B are arranged side by side in the longitudinal direction is illustrated for reference in one drying device 42.
When a plurality of the first hot air ducts 5A and the second hot air ducts 5B are arranged side by side, the distance between the hot air ducts 5 adjacent to each other in the longitudinal direction is not particularly limited and is appropriately set.

<1st warm air duct>
FIG. 7 is a front view in which the first hot air duct 5A and the second hot air duct 5B provided in the drying device 42 are taken out one by one. FIG. 7 shows the first hot air duct 5A and the second hot air duct 5B in a state before the covering sheet 7 covers the hot air blowing portion (the state in which the covering sheet 7 is stored). The thin broken line in FIG. 7 shows the transport path of the laminated polarizing film 2Y.
FIG. 8 is a bottom view of the first warm air duct 5A in a state before the covering sheet 7 covers the hot air blowing portion, FIG. 9 is a left side view of the first warm air duct 5A, and FIG. 10 is a first temperature. The right side view of the air duct 5A, FIG. 11 is a top view of the first hot air duct 5A, and FIGS. 12 and 13 are cuts in the middle part of the first warm air duct 5A in the width direction in a direction orthogonal to the width direction. It is also an enlarged enlarged cross-sectional view.
In FIGS. 8 to 11 and 14, the intermediate portion in the width direction in which the same structure is continuous is omitted.

With reference to FIGS. 7 to 13, the first warm air duct 5A is composed of an elongated hollow body extending in the width direction. The elongated first warm air duct 5A is arranged with its long axis substantially parallel to the width direction of the laminated polarizing film 2Y.
The first hot air duct 5A includes a warm air blowing portion 52 having an opening 51 (nozzle portion), a one side surface portion 53 arranged on one side of the warm air blowing portion 52, and the warm air blowing portion 52. It has a other side surface portion 54 arranged on the opposite side portion of the above, and a top surface portion 55 arranged so as to bridge between the one side surface portion 53 and the other side surface portion 54. The hollow first warm air duct 5A is formed by connecting the warm air blowing portion 52, the one side surface portion 53, the top surface portion 55, and the other side surface portion 54 to each other.
The warm air blowing portion 52 is arranged to face the laminated polarizing film 2Y (polarizing film).
The warm air blowing portion 52 is provided with an opening 51 for blowing warm air. The opening 51 is a slit-shaped opening extending in the width direction (long axis direction of the first warm air duct 5A). The openings 51 are formed in pairs, for example. The opening 51 is not limited to an elongated slit-shaped opening, and may be, for example, a plurality of small holes arranged in the width direction (not shown). Hot air is supplied into the first hot air duct 5A from a hot air supply machine (not shown), and the hot air is blown from the hot air blowing portion 52 to the laminated polarizing film 2Y through the opening 51.
The outer surface of the warm air blowing portion 52 is a substantially flat flat surface except for the opening 51.
The first hot air duct 5A including the hot air blowing portion 52 is usually formed of a metal such as iron or stainless steel.

The first hot air duct 5A is provided with a covering sheet 7. The covering sheet 7 covers a region of the warm air blowing portion 52 corresponding to the widthwise end portion of the laminated polarizing film 2Y.
One first warm air duct 5A may be provided with one covering sheet 7 that covers the region corresponding to the widthwise end portion of the laminated polarizing film 2Y in the warm air blowing portion 52, but is preferable. One first warm air duct 5A is provided with two or more covering sheets 7.

Here, the width of the laminated polarizing film 2Y (polarizing film) to be dried varies. That is, usually, one manufacturing apparatus 10 is used to manufacture laminated polarizing films 2Y (polarizing films) having various widths. A laminated polarizing film 2Y (polarizing film) having a width of, for example, 500 mm to 4000 mm can be manufactured by one manufacturing apparatus 10. Therefore, the drying device 42 can also dry the laminated polarizing film 2Y having various widths. Usually, the length in the width direction of the first warm air duct 5A is designed to be larger than the maximum width thereof in consideration of manufacturing the laminated polarizing film 2Y having the largest width (the laminated polarizing film having the maximum width). Therefore, the case where the relatively wide laminated polarizing film 2Y is dried and the case where the relatively narrow laminated polarizing film 2Y is dried correspond to the widthwise end portion of the laminated polarizing film 2Y in the warm air blowing portion 52. The area to be used is different. When the laminated polarizing film 2Y having a relatively wide width is conveyed and dried, the widthwise end portion of the laminated polarizing film 2Y passes relatively outside in the width direction of the warm air blowing portion 52. When the laminated polarizing film 2Y having a relatively narrow width is transported and dried, the widthwise end portion of the laminated polarizing film 2Y is inside the width direction of the warm air blowing portion 52 with respect to the wide laminated polarizing film 2Y. Pass through.
Even when the laminated polarizing films 2Y (polarizing films) having different widths are dried, it is desirable to prevent the edges of the laminated polarizing films 2Y from being scratched. Therefore, it is preferable that a plurality of covering sheets 7 are provided to cover different regions in the width direction of the warm air blowing portion 52.

The plurality of covering sheets 7 are composed of, for example, the first covering sheet 7a covering the region corresponding to the widthwise end portion of the first laminated polarizing film (first polarizing film) having a predetermined width, and the first laminated polarizing film. Also includes a second coating sheet 7b that covers the region corresponding to the widthwise end of the narrow second laminated polarizing film (second polarizing film). As shown in the illustrated example, the covering sheet 7 covers a region corresponding to the widthwise end portion of the third laminated polarizing film (third polarizing film) narrower than the second laminated polarizing film 2Y. Includes more.
The first laminated polarizing film, the second laminated polarizing film, and the third laminated polarizing film satisfy the relationship of the width of the first laminated polarizing film> the width of the second laminated polarizing film> the width of the third laminated polarizing film. .. In the illustrated example, the first warm air duct 5A includes the first to third covering sheets 7a, 7b, and 7c corresponding to the laminated polarizing film (polarizing film) having the three types of widths. Even when the laminated polarizing films are dried, scratches on their edges can be prevented. The covering sheet 7 is not limited to the case where it is provided corresponding to each of the three types of width-width laminated polarizing films (polarizing film), and the coating sheet 7 corresponds to each of four or more types of width-width laminated polarizing films 4 More than one sheet may be provided.

From another point of view, there are a pair of left and right edges of the laminated polarizing film in the width direction. Therefore, from the viewpoint of preventing scratches on the right end portion and the left end portion (both ends in the width direction) of the laminated polarizing film in the width direction, the covering sheet 7 is a single laminated polarizing film (polarizing film) having a predetermined width. It is preferable that it is composed of a pair of left and right portions corresponding to the right end portion and the left end portion in the width direction. In this case, a coating sheet 7 in which a pair of left and right is paired is provided for one laminated polarizing film (polarizing film) having a predetermined width.
Therefore, in a more preferred embodiment, the first coating sheet 7a has a first temperature so as to cover regions corresponding to the right end portion and the left end portion in the width direction of the first laminated polarizing film (first polarizing film), respectively. The wind duct 5A is provided on the left and right sides in the width direction, respectively.
The second coating sheet 7b is in the width direction of the first warm air duct 5A so as to cover the regions corresponding to the right end portion and the left end portion in the width direction of the second laminated polarizing film (second polarizing film), respectively. It is provided on each side.
The third coating sheet 7c is in the width direction of the first warm air duct 5A so as to cover the regions corresponding to the right end portion and the left end portion in the width direction of the third laminated polarizing film (second polarizing film), respectively. It is provided on each side.
The pair of left and right first covering sheets 7a are arranged on the outermost side in the width direction of the first warm air duct 5A, and the pair of left and right second covering sheets 7b are arranged inside the first covering sheet 7a in the width direction. The pair of left and right third covering sheets 7c are arranged inside in the width direction with respect to the second covering sheet 7b.
The first covering sheet 7a, the second covering sheet 7b, and the third covering sheet 7c (a plurality of covering sheets 7) are arranged side by side with a gap in the width direction so as not to overlap each other.

Further, the covering sheet 7 may be provided in the first hot air duct 5A in a state of being independent from the first hot air duct 5A, or may be partially connected to the first hot air duct 5A. It may be provided in the first warm air duct 5A. Since the setting work of the covering sheet 7 can be performed efficiently, one end of the covering sheet 7 is fixed to one side of the warm air blowing portion 52 of the first hot air duct 5A, and the opposite of the covering sheet 7. It is preferable that the end portion is a free end (see FIGS. 12 and 13). Further, it is more preferable that the rod member 6 is attached to the opposite end portion of the covering sheet 7 which is the free end. Examples of the method of attaching the rod member 6 to the opposite end of the covering sheet 7 include attachment using a fastener such as a screw screw or a bolt nut.
The rod member 6 is, for example, a metal cylinder, and may have a solid shape or a hollow shape (pipe shape). Since the weight is relatively small and the workability is improved, the rod member 6 is preferably hollow as shown in the figure. The rod member 6 is not limited to a cylinder, and may have another shape such as a quadrangular prism.
As shown in FIGS. 12 and 13, the covering sheet 7 (covered sheet 7 in the stored state) before covering the warm air blowing portion 52 is wound around the rod member 6 and held by the holding portion 8. There is.

The holding portion 8 is provided on one side surface portion 53, which is one side portion of the warm air blowing portion 52. The holding portion 8 is fixed to one side surface portion 53 of the first warm air duct 5A. Examples of the method of fixing the holding portion 8 to the one side surface portion 53 include attachment using fasteners such as screw screws and bolts and nuts, welding, and the like. A pair of left and right holding portions 8 are provided in the width direction. The holding portion 8 has a fixing portion 81 for fixing one end of the covering sheet 7 and a receiving portion 82 for holding the rod member 6. The fixing portion 81 includes a main bar provided on the holding portion 8 and a sub-bar detachably attached to the main bar. The secondary bar is smaller than the primary bar. Examples of the method of attaching the secondary bar to the main bar include attachment using fasteners such as screw screws and bolts and nuts. By sandwiching one end of the covering sheet 7 between the main bar and the sub bar, one end of the covering sheet 7 is fixed to the fixing portion 81 of the holding portion 8. The receiving portion 82 is open on the upper side in the vertical direction (the vertical direction is the direction perpendicular to the horizontal direction), and has a substantially U-shape when viewed from the front as shown in FIG. The receiving portions 82 are provided at a plurality of locations, and in the illustrated example, they are provided at three different locations when viewed from the front.

Specifically, each one end portion of the first to third covering sheets 7a, 7b, 7c is fixed to one side surface portion 53, which is one side portion of the warm air blowing portion 52, respectively. In the illustrated example, one end of each of the first to third covering sheets 7a, 7b, 7c is fixed to the fixing portion 81 of the holding portion 8. Therefore, each one end portion of the first to third covering sheets 7a, 7b, 7c is fixed to the one side surface portion 53 via the holding portion 8.
The opposite ends of the first to third covering sheets 7a, 7b, and 7c are free ends. A rod member 6 is attached to each of the opposite ends of the first to third covering sheets 7a, 7b, and 7c. Both ends of the rod member 6 have a large diameter in order to make it easy to hold.
The pair of left and right first covering sheets 7a are wound around the rod member 6 attached to the opposite end portion thereof. The rod member 6 around which the first covering sheet 7a is wound is placed on the receiving portion 82 of the holding portion 8 and held by the holding portion 8.
The pair of left and right second covering sheets 7b are wound around the rod member 6 attached to the opposite end portion thereof. The rod member 6 around which the second covering sheet 7b is wound is placed on another receiving portion 82 of the holding portion 8 and held by the holding portion 8.
The pair of left and right third covering sheets 7c are wound around the rod member 6 attached to the opposite end portion thereof. The rod member 6 around which the third covering sheet 7c is wound is placed on another receiving portion 82 of the holding portion 8 and held by the holding portion 8.

On the other hand, the other side surface portion 54, which is the opposite side portion of the warm air blowing portion 52, is provided with a locking portion 9 capable of locking the rod member 6. The locking portion 9 is fixed to the other side surface portion 54 of the first warm air duct 5A. Examples of the method of fixing the locking portion 9 to the other side surface portion 54 include attachment using a fastener, welding, and the like. A pair of left and right locking portions 9 are provided in the width direction. The locking portion 9 has a groove portion 91 that receives the rod member 6 and a cylindrical portion 92 that contacts the covering sheet 7. The groove 91 is open on the upper side in the vertical direction (the vertical direction is the direction perpendicular to the horizontal direction), and has a substantially U-shape when viewed from the front as shown in FIG. The columnar portion 92 extends in the width direction. The cylindrical portion 92 may be fixedly provided on the locking portion 9, or may be pivotally supported by the locking portion 9 in a rotatable state. Preferably, the cylindrical portion 92 is rotatably provided.
The groove portion 91 is arranged closer to the other side surface portion 54, and the columnar portion 92 is arranged outside the groove portion 91.
The holding portion 8 and the locking portion 9 are made of metal, for example.

<Second warm air duct>
FIG. 14 is a top view of the second warm air duct 5B in a state before the covering sheet 7 covers the warm air blowing portion 52.
With reference to FIGS. 7 and 14, the second hot air duct 5B, like the first hot air duct 5A, is composed of an elongated hollow body extending in the width direction and is arranged to face the laminated polarizing film (polarizing film). It has a warm air blowing portion 52.
As is clear from comparing FIGS. 7 and 14 showing the second hot air duct 5B with FIGS. 7 to 13 showing the first hot air duct 5A, the second hot air duct 5B is (a). The hot air blowing portion 52 is arranged on the upper side in the vertical direction, and (b) the locking portion 9 is not provided. The details of the second hot air duct 5B are the same as those in the <1st hot air duct> column, except for the above (a) and (b). Therefore, the description of the second hot air duct 5B is described by replacing "first hot air duct 5A" in the above <first hot air duct> column with "second hot air duct 5B". A specific example of 5B will be described here.
The other side surface portion 54 of the second warm air duct 5B may be provided with a locking portion for locking the rod member 6 (not shown).

<1st hot air duct and 2nd hot air duct whose hot air outlet is covered with a covering sheet>
As described above, in the first hot air duct 5A shown in FIGS. 7 to 13 and the second hot air duct 5B shown in FIGS. 7 and 14, the warm air blowing portion 52 is not covered by the covering sheet 7. The covering sheet 7 is held by the holding portion 8. That is, the above-mentioned first hot air duct 5A and second hot air duct 5B are in a state before the drying device 42 is operated and before the covering sheet 7 is set. In operating the drying device 42, the area corresponding to the widthwise end of the laminated polarizing film 2Y (polarizing film) in the warm air blowing portion 52 of the first warm air duct 5A is covered with the covering sheet 7. Similarly, the area corresponding to the widthwise end of the laminated polarizing film 2Y (polarizing film) in the warm air blowing portion 52 of the second warm air duct 5B is covered with the covering sheet 7.

FIG. 15 is a front view showing a procedure of covering the warm air blowing portion 52 of the first hot air duct 5A with the covering sheet 7.
As shown in FIG. 8A, the covering sheet 7 is taken out from the holding portion 8. In the illustrated example, the case where the first covering sheet 7a is taken out is illustrated. Since the rod member 6 is attached to the opposite end of the covering sheet 7 and the covering sheet 7 is wound around the rod member 6, the rod member 6 is removed from the holding portion 8 and the covering sheet 7 is fed out from the rod member 6. While pulling out the covering sheet 7. Since one end of the covering sheet 7 is fixed to the holding portion 8, the drawn covering sheet 7 does not fall off from the first warm air duct 5A. Next, as shown in FIG. 6B, the covering sheet 7 is inverted over the columnar portion 92 of the locking portion 9 while being bridged over the warm air blowing portion 52. Finally, as shown in FIG. 6C, the rod member 6 is inserted into the groove 91 of the locking portion 9. The covering sheet 7 includes the warm air blowing portion 52 so as to straddle the holding portion 8 (one side portion of the warm air blowing portion 52) and the locking portion 9 (opposite side portion of the warm air blowing portion 52). It is bridged by.
By simply removing the rod member 6 from the holding portion 8 and locking the rod member 6 to the locking portion 9 in this way, the covering sheet 7 can be set on the warm air blowing portion 52 extremely easily.

FIG. 16 is an enlarged cross-sectional view showing a state in which the first covering sheet 7a is set in the warm air blowing portion 52 of the first hot air duct 5A. FIG. 16 is also an enlarged cross-sectional view of the first warm air duct 5A in the state of FIG. 15 (c) cut at a longitudinal portion of the covering sheet 7. The thin broken line in FIG. 16 indicates the transport path of the laminated polarizing film 2Y.
With reference to FIG. 16, the rod member 6 inserted into the groove 91 is suspended in the air. One end portion 71 of the covering sheet 7 is fixed to one side surface portion 53 (holding portion 8) which is one side portion of the warm air blowing portion 52, and the rod member 6 is attached to the opposite end portion 72 of the covering sheet 7. Is suspended in the air, so that the covering sheet 7 is in a state in which tension is applied by the weight of the rod member 6. In particular, the tension is applied so that the covering sheet 7 is in close contact with the warm air blowing portion 52. In this way, since the covering sheet 7 covers the region of the warm air blowing portion 52 in a tense state, it becomes difficult for the covering sheet 7 to separate from the warm air blowing portion 52. As a method of putting the covering sheet 7 in a tense state when covering the region of the warm air blowing portion 52, for example, a method of pulling the covering sheet 7 using an elastic member such as a spring can be adopted. In this respect, as described above, the structure of the covering sheet 7 is extremely simple if the method uses the weight of the rod member 6 (weight of the rod member 6) to apply tension to the covering sheet 7. Further, the rod member 6 can be used as an operation portion when the covering sheet 7 is taken out from the holding portion 8 or the covering sheet 7 is stored in the holding portion 8.

FIG. 17 is a bottom view of the first warm air duct 5A in a state where the first covering sheet 7a is set in the warm air blowing portion 52, as viewed from the vertical direction. FIG. 17 is also a view seen from the direction of arrow XVII in FIG. In FIG. 17, the intermediate portion in the width direction in which the same structure is continuous is omitted (the same applies to FIGS. 19 to 21).
With reference to FIG. 17, the covering sheet 7 covers the region of the warm air blowing portion 52 corresponding to the widthwise end portion of the laminated polarizing film 2Y (polarizing film). In the figure, the widthwise side edges 2Y-1,2Y-2 of the laminated polarizing film 2Y (polarizing film) are represented by alternate long and short dash lines which are virtual lines. The widthwise end portion of the laminated polarizing film 2Y (polarizing film) refers to a portion near the side edge including the widthwise side edge.
Preferably, the covering sheet 7 is arranged so that the widthwise side edge of the laminated polarizing film 2Y is located substantially in the center of the covering sheet 7 in the width direction. One end of the covering sheet 7 is fixed so as to have such an arrangement.
In the illustrated example, the outermost first coating sheet 7a covers the regions corresponding to both ends in the width direction of the laminated polarizing film 2Y. The first covering sheet 7a is a covering sheet 7 arranged so as to cover the regions corresponding to both ends in the width direction of the first laminated polarizing film (first polarizing film). Therefore, FIG. 17 is an example of drying the widest first laminated polarizing film. The width W1 of the first laminated polarizing film is the length between both edges in the width direction.
Since the region of the warm air blowing portion 52 is covered by the first coating sheet 7a, even if the widthwise end portion is curled when the first laminated polarizing film is conveyed and dried, the warm air blowing portion is formed. There is no direct contact with 52. Even if the end portion is curled, the end portion of the first laminated polarizing film comes into contact with the covering sheet 7, so that the end portion can be prevented from being scratched.

FIG. 18 is an enlarged cross-sectional view showing a state in which the first covering sheet 7a is set in the warm air blowing portion 52 of the second warm air duct 5B. The thin broken line in FIG. 18 shows the transport path of the laminated polarizing film 2Y.
With reference to FIG. 18, for the second hot air duct 5B as well, the rod member 6 is removed from the holding portion 8 and the region of the warm air blowing portion 52 is formed by the first covering sheet 7a in the same manner as in the first hot air duct 5A. Bring the rod member 6 to the other side surface portion 54 while covering it. By simply moving the rod member 6 to the other side surface portion 54 in this way, the covering sheet 7 can be set on the warm air blowing portion 52 extremely easily. In the illustrated example, the case where the first covering sheet 7a is set is illustrated.
As for the second hot air duct 5B, similarly to the first hot air duct 5A, the covering sheet 7 covers the region of the warm air blowing portion 52 in a state where tension is applied by the weight of the rod member 6.

FIG. 19 is a bottom view of the second warm air duct 5B in a state where the first covering sheet 7a is set in the warm air blowing portion 52, as viewed from the vertical direction. FIG. 19 is also a view seen from the direction of arrow XIX in FIG.
With reference to FIG. 19, in the second warm air duct 5B as well, the covering sheet 7 is the widthwise end of the laminated polarizing film 2Y (polarizing film) of the warm air blowing portion 52, as in the case of the first hot air duct 5A. It covers the area corresponding to the part. In the figure, the widthwise side edges 2Y-1,2Y-2 of the laminated polarizing film 2Y (polarizing film) are represented by alternate long and short dash lines which are virtual lines.
Preferably, the covering sheet 7 is arranged so that the widthwise side edge of the laminated polarizing film 2Y is located substantially in the center of the covering sheet 7 in the width direction. One end of the covering sheet 7 is fixed so as to have such an arrangement.
In the illustrated example, the outermost first coating sheet 7a covers the regions corresponding to both ends in the width direction of the laminated polarizing film 2Y.
As for the second warm air duct 5B as well, since the region of the warm air blowing portion 52 is covered with the first covering sheet 7a, when the first laminated polarizing film is conveyed and dried, the end portion in the width direction thereof is formed. Even if it is curled, it does not come into direct contact with the warm air blowing portion 52. Therefore, it is possible to prevent the edge of the first laminated polarizing film from being scratched.

[Manufacturing method of basic polarizing film and laminated polarizing film]
<Process of covering the warm air blowing part with a covering sheet>
Before operating the drying device 42, a predetermined covering sheet 7 is taken out from the first hot air duct 5A and the second hot air duct 5B in the state shown in FIG. 7, and set in the warm air blowing portion 52. Regarding the procedure for covering the warm air blowing portion 52 with the covering sheet 7 and the structure of the first and second hot air ducts 5A and 5B after covering with the covering sheet 7, the above <covering sheet allows the warm air blowing portion to be formed. Please refer to the column of Covered 1st Hot Air Duct and 2nd Hot Air Duct>.
For example, as shown in FIGS. 16 to 19, the first coating sheet 7a covers the regions corresponding to both ends in the width direction of the first laminated polarizing film, the first warm air duct 5A and the second hot air duct 5B. Prepare.

<Manufacturing process of basic polarizing film and laminated polarizing film>
The manufacturing apparatus 10 having the drying apparatus 42 in which the covering sheet 7 is set is operated to manufacture a basic polarizing film and a laminated polarizing film.
The production of the basic polarizing film and the production of the laminated polarizing film may be carried out by a conventionally known method. Hereinafter, a brief description will be given.
With reference to FIG. 6, the untreated film raw fabric Y is pulled out from the feeding portion, and the film raw fabric Y is conveyed to the swelling treatment tank 311 by the transport device 101 to swell the film raw fabric Y. Then, the film raw fabric Y is dyed in the dyeing treatment tank 312 and then crosslinked in the crosslinking treatment tank 313. The raw film Y after cross-linking is stretched while being conveyed in the stretching liquid of the stretching treatment tank 314. The basic polarizing film 1Y is obtained by washing the original film Y after dyeing and stretching in the washing treatment tank 315 and then drying it in the drying device 32.
An arbitrary film is laminated on the obtained long strip-shaped basic polarizing film 1Y.
As shown in FIG. 6, an adhesive is applied to one surface of the long strip-shaped first arbitrary film 21Y (for example, a protective film) by the adhesive coating portion 412. An adhesive is applied to one side of a long strip-shaped second arbitrary film 22Y (for example, a protective film) by the adhesive coating portion 413. These are attached to one side and the opposite side of the basic polarizing film 1Y and inserted into the nip roll. The adhesive of the laminated body is cured. When an active energy ray-curable adhesive is used, the adhesive is cured by irradiating the adhesive with active energy rays, and the first optional film / adhesive layer / basic polarizing film is used. A laminated polarizing film 2Y composed of / an adhesive layer / a second arbitrary film can be obtained.

<Drying process>
The laminated polarizing film 2Y is introduced into the drying device 42. In the drying device 42, warm air is blown from the hot air blowing portion 52 of the first hot air duct 5A and the second hot air duct 5B. The air volume and temperature of the warm air are not particularly limited, and may be set in the same manner as conventionally known settings. The laminated polarizing film 2Y is dried by conveying the laminated polarizing film 2Y (polarizing film) in the longitudinal direction while blowing warm air from the first and second warm air ducts 5A and 5B covered with the coating sheet 7. .. The warm air from the first hot air duct 5A is blown in a direction substantially orthogonal to one surface of the laminated polarizing film 2Y, for example, and the warm air from the second hot air duct 5B is, for example, the laminated polarizing film 2Y. It is sprayed in a direction substantially orthogonal to the opposite surface of. After blowing warm air to dry, the laminated polarizing film 2Y is wound up.
The laminated polarizing film 2Y is dried by warm air, and at this time, the widthwise end portion of the laminated polarizing film 2Y may be curled. In particular, since the laminated polarizing film 2Y (polarizing film) contains a polarizer, edge curl is likely to occur during drying.
Conventionally, the curled end portion comes into contact with the uneven warm air blowing portion, the edge portion of the polarizing film is damaged, and the film is slightly scraped off, resulting in film slag. This film slag accumulates on the hot air outlet and adheres to the curled end, creating a vicious cycle.
In this regard, according to the present invention, since the region of the warm air blowing portion 52 corresponding to the widthwise end portion of the laminated polarizing film 2Y (polarizing film) is covered by the covering sheet 7, the curled end portion is formed. It comes into contact with the surface of the covering sheet 7. Since the coating sheet 7 has excellent surface smoothness, the edges of the laminated polarizing film 2Y are not easily scratched, and film slag due to the polarizing film can be prevented from being generated.

16 to 19 show a case where the first laminated polarizing film is manufactured and dried, but when a laminated polarizing film having a different width from the first laminated polarizing film is manufactured, the coating sheet 7 is replaced.
Specifically, for the first hot air duct 5A, the first covering sheet 7a is removed in the reverse procedure of FIG. 15, and the first covering sheet 7a is once returned to the state of FIGS. 8 to 13. Next, the second covering sheet 7b is removed, and the second covering sheet 7b is set in the warm air blowing portion 52 of the first hot air duct 5A according to the procedure described with reference to FIG. The second hot air duct 5B is also replaced with the second covering sheet 7b in the same manner as the first hot air duct 5A.
FIG. 20 is a bottom view of the first warm air duct 5A in a state where the second covering sheet 7b is set in the warm air blowing portion 52, as viewed from the vertical direction.
With reference to FIG. 20, the second coating sheet 7b covers the region of the warm air blowing portion 52 corresponding to the widthwise end portion of the second laminated polarizing film. In the figure, both side edges of the laminated polarizing film (polarizing film) in the width direction are represented by alternate long and short dash lines, which are virtual lines. The width W2 of the second laminated polarizing film is smaller than the width W1 of the first laminated polarizing film.
The first hot air duct 5A and the second hot air duct 5B covered with the second coating sheet 7b are prepared and dried while transporting the second laminated polarizing film, whereby the second laminated polarizing film is also produced in the width direction. It is possible to prevent scratches on the edges.

Similarly, the third covering sheet 7c can be set in the hot air blowing portion 52 of the first hot air duct 5A and the second hot air duct 5B.
FIG. 21 is a bottom view of the first warm air duct 5A in a state where the third covering sheet 7c is set in the warm air blowing portion 52, as viewed from the vertical direction.
With reference to FIG. 21, the third coating sheet 7c covers the region of the warm air blowing portion 52 corresponding to the widthwise end portion of the third laminated polarizing film. The width W3 of the third laminated polarizing film is smaller than the width W2 of the second laminated polarizing film.
The first hot air duct 5A and the second hot air duct 5B covered with the third coating sheet 7c are prepared and dried while conveying the third laminated polarizing film, so that the third laminated polarizing film is also produced in the width direction. It is possible to prevent scratches on the edges.

In the drying method of the present invention, two or more covering sheets 7 (first to third covering sheets 7a, 7b, 7c) are provided on the first and second warm air ducts 5A and 5B, and laminated with different widths. Depending on the polarizing film (polarizing film), the covering sheet 7 selected from these covering sheets 7 is used to cover the region of the warm air blowing portion 52.
Therefore, according to the drying method and the drying apparatus of the present invention, laminated polarizing films (polarizing films) having various widths can be dried, and scratches on the edges thereof can be prevented.
Further, since a plurality of covering sheets 7 are provided in the warm air duct 5 according to the type (difference in width) of the laminated polarizing film to be dried, the covering sheet 7 can be easily replaced.
In particular, since one end of the covering sheet 7 is fixed and the rod member 6 is attached to the opposite end, the covering sheet 7 can be set and stored by operating the rod member 6. Therefore, the replacement work of the covering sheet 7 can be easily performed.

[Modification example]
The above-mentioned drying device 42 corresponds to the laminated polarizing film 2Y (in other words, the conveying path of the polarizing film is substantially horizontal) that is conveyed substantially horizontally, and the first hot air duct 5A and the second hot air duct. 5B is arranged. However, the present invention is not limited to the case where the first and second warm air ducts 5A and 5B are arranged with respect to the polarizing film conveyed substantially horizontally, and for example, the first and the second with respect to the polarizing film conveyed while meandering. The 1st and 2nd warm air ducts 5A and 5B may be arranged, or the 1st and 2nd hot air ducts 5A and 5B may be arranged with respect to the polarizing film conveyed in the direction inclined with respect to the vertical direction or the horizontal direction. May be placed.

[Use of polarizing film, etc.]
The polarizing film of the present invention (basic polarizing film and laminated polarizing film) is typically used as an optical film for a display such as a liquid crystal display device or an organic display device.
Further, the polarizing film of the present invention is not limited to the case where it is used for the above-mentioned display, and can be used for applications other than the display. Applications other than displays include optical equipment, buildings, medical / food fields, and the like. When a polarizing film is used in an optical instrument, the polarizing film is processed into, for example, a polarizing lens, a transparent radio wave blocking film, or the like. When a polarizing film is used in an electronic device, the polarizing film is processed into, for example, a dimming window film. When the polarizing film is used in the medical / food field, the polarizing film is processed into, for example, a photodegradation prevention film.

1,2,1Y, 2Y Polarizing film 2Y-1,2Y-2 Width side edge of laminated polarizing film (polarizing film) 5,5A, 5B Warm air duct 52 Warm air blowing part 6 Bar member 7 Coating sheet 71 Coating sheet One end 72 Opposite end of the covering sheet 7a First covering sheet 7b Second covering sheet 7c Third covering sheet 8 Holding part 9 Locking part

Claims (8)

In a drying device that blows warm air onto the polarizing film in the process of transporting the long strip-shaped polarizing film in the longitudinal direction.
A warm air duct having a hot air blowing portion arranged to face the surface of the polarizing film, and a hot air duct.
A polarizing film drying device comprising a coating sheet covering a region of the warm air blowing portion corresponding to the widthwise end portion of the polarizing film. One end of the covering sheet is fixed to one side of the hot air blowing portion of the warm air duct, and the opposite end of the covering sheet is a free end.
A rod member is attached to the opposite end portion of the covering sheet, and a locking portion capable of locking the rod member is provided on the opposite side portion of the warm air blowing portion of the hot air duct.
The polarizing film drying apparatus according to claim 1, wherein the covering sheet covers the region by locking the rod member to the locking portion. The polarizing film drying apparatus according to claim 1 or 2, wherein the covering sheet covers the region in a tensioned state. Having two or more of the covering sheets
The first coating sheet covers the area corresponding to the widthwise edge of the first polarizing film.
The polarizing film drying apparatus according to any one of claims 1 to 3, wherein the second coating sheet covers the widthwise end portion of the second polarizing film narrower than the first polarizing film. The polarizing film drying apparatus according to any one of claims 1 to 4, wherein the covering sheet is composed of a pair of left and right so as to cover regions corresponding to both ends in the width direction of the polarizing film. The polarizing film drying apparatus according to any one of claims 1 to 5, wherein the coating sheet includes a polyimide resin sheet. In the drying method of drying the polarizing film in the process of transporting the long strip-shaped polarizing film in the longitudinal direction,
A step of covering a region of the hot air blowing portion having a warm air blowing portion arranged opposite to the surface of the polarizing film corresponding to the widthwise end portion of the polarizing film with a covering sheet. ,
A method for drying a polarizing film, comprising a step of drying the polarizing film by conveying the polarizing film in the longitudinal direction while blowing warm air from a hot air duct covered with the covering sheet. The hot air duct is provided with two or more of the covering sheets.
The method for drying a polarizing film according to claim 7, wherein the region is covered with a coating sheet selected from the two or more coating sheets according to the polarizing films having different widths.

Images