Drying apparatus and drying method for polarizing film

Abstract

The present application provides a drying device and drying method for polarizing film, which can prevent the polarizing film end from being damaged. The drying device blows warm air to a long strip-shaped polarizing film during conveying the polarizing film along the length direction, and has a warm air pipeline (5) with a warm air blowing part (52) arranged opposite to the surface of the polarizing film (2Y), and a covering sheet (7) covering the area in the warm air blowing part (52) corresponding to the width direction end of the polarizing film (2Y).

Description

TECHNICAL FIELD

[0001] The present application relates to a drying apparatus for a polarizing film including a polarizing plate and a drying method thereof. BACKGROUND

[0002] In the past, as a constituent material of a liquid crystal display device, a polarizing light sunglass, or the like, a polarizing film including a polarizing plate has been used. As the polarizing film, for example, a laminate in which a protective film is layered on a polarizing plate or the like can be cited.

[0003] Such a polarizing film composed of a laminate is obtained by adhering a protective film to a polarizing plate using an adhesive after the polarizing plate is manufactured.

[0004] For example, in Patent Document 1, after a long strip-shaped polarizing plate is adhered to a protective film (cellulose acetate-based resin film) using an adhesive to form a polarizing film (laminate), the polarizing film is dried using a drying oven.

[0005] The drying oven is of a type in which a long strip-shaped laminate is conveyed while warm air is blown against the laminate. The drying oven of the type in which warm air is blown generally has a warm air duct that is formed with a warm air blow-out portion that blows warm air against the surface of the polarizing film.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2013-205721

[0007] However, if the polarizing film including the polarizing plate is dried by blowing warm air against it, there is a case in which the width direction end portion of the polarizing film is curled.

[0008] If the polarizing film whose end portion is curled at the time of drying like this is conveyed while being dried using a warm air duct, there is a case in which the curled end portion comes into contact with the warm air blow-out portion. If the end portion of the polarizing film comes into contact with the warm air blow-out portion, there is a risk that the end portion of the polarizing film is damaged by being shaved off by the warm air blow-out portion. Moreover, shaving off the end portion of the polarizing film causes film scraps to be generated, and there is a risk that the film scraps adhere to the end portion of the polarizing film. Such damage to the end portion and the adhesion of foreign matter such as the film scraps reduce the yield of the polarizing film, and improvement thereof is required.

[0009] In addition, polarizing films of various lateral widths are dried depending on the manufacturing lot. The polarizing film of a larger lateral width and the polarizing film of a smaller lateral width differ in the position of the width direction end portion, and thus differ in the position at which the warm air blow-out portion is contacted. SUMMARY

[0010] A first object of the present application is to provide a drying apparatus for a polarizing film and a drying method that can prevent damage to the end portion of the polarizing film.

[0011] The second object of the present application is to provide a drying apparatus and a drying method for polarizing films, which can prevent end portions of polarizing films from being damaged even when the polarizing films having different lateral widths are dried.

[0012] The drying apparatus for polarizing films of the present application blows warm air against a long strip-shaped polarizing film being conveyed in a length direction, and has a warm air duct having a warm air blowing portion disposed opposite to a surface of the polarizing film, and a cover sheet covering a region in the warm air blowing portion corresponding to an end portion in a width direction of the polarizing film.

[0013] The preferred drying apparatus for polarizing films of the present application is such that one end portion of the cover sheet is fixed to one side portion of the warm air blowing portion of the warm air duct, and the opposite end portion of the cover sheet is provided as a free end, a rod member is attached to the opposite end portion of the cover sheet, and a clamping portion capable of clamping the rod member is provided to the opposite side portion of the warm air blowing portion of the warm air duct, and the cover sheet covers the region by clamping the rod member to the clamping portion.

[0014] The preferred drying apparatus for polarizing films of the present application is such that the cover sheet covers the region in a state of being applied with tension.

[0015] The preferred drying apparatus for polarizing films of the present application is such that the cover sheet has two or more pieces, a first cover sheet covers a region corresponding to an end portion in a width direction of a first polarizing film, and a second cover sheet covers an end portion in a width direction of a second polarizing film having a narrower width than the first polarizing film.

[0016] The preferred drying apparatus for polarizing films of the present application is such that the cover sheet is composed of a pair of left and right pieces so as to cover regions corresponding to both end portions in a width direction of the polarizing film, respectively.

[0017] The preferred drying apparatus for polarizing films of the present application is such that the cover sheet contains a polyimide-based resin sheet.

[0018] According to another aspect of the present application, there is provided a drying method for polarizing films.

[0019] The drying method for polarizing films of the present application dries a long strip-shaped polarizing film being conveyed in a length direction, and has a step of covering a region in a warm air blowing portion of a warm air duct having the warm air blowing portion disposed opposite to a surface of the polarizing film, using a cover sheet, and a step of blowing warm air from the warm air duct covered by the cover sheet while conveying the polarizing film in the length direction, thereby drying the polarizing film.

[0020] The drying method of the preferred polarizing film of the present application is a method in which the warm air duct is provided with two or more of the cover sheets, and the regions are covered with the cover sheets selected from among the two or more cover sheets according to the lateral width of the polarizing film.

[0021] According to the drying apparatus and the drying method of the present application, the polarizing film can be dried while preventing damage to the end portion of the polarizing film.

[0022] Further, according to the preferred drying apparatus and the drying method of the present application, the polarizing film having a different lateral width can be dried while preventing damage to the end portion. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a partial plan view of a polarizing film of the present application.

[0024] Figure 2 is a sectional view of a polarizing film (basic polarizing film) of one embodiment (sectional view taken along line II-II of Figure 1 ).

[0025] Figure 3 is a sectional view of a polarizing film (basic polarizing film) of another embodiment.

[0026] Figure 4 is a sectional view of a polarizing film (laminated polarizing film) of still another embodiment.

[0027] Figure 5 is a sectional view of a polarizing film (laminated polarizing film) of further another embodiment.

[0028] Figure 6 is a schematic front view showing a manufacturing apparatus of a polarizing film.

[0029] Figure 7 is a front view of a first warm air duct and a second warm air duct showing a state before a warm air blowing portion is covered with a cover sheet.

[0030] Figure 8 is a bottom view of the first warm air duct as viewed in the direction of arrow VIII of Figure 7 .

[0031] Figure 9 is a left side view of the first warm air duct as viewed in the direction of arrow IX of Figure 7 .

[0032] Figure 10 is a right side view of the first warm air duct as viewed in the direction of arrow X of Figure 7 .

[0033] Figure 11 is a right side view of the first warm air duct as viewed in the direction of arrow X of Figure 7The top view of the first heating duct is observed in the direction of arrow XI.

[0034] Figure 12 Therefore Figure 11 Enlarged cross-sectional view of the section cut along line XII-XII.

[0035] Figure 13 Therefore Figure 11 Enlarged cross-sectional view of the section cut along line XIII-XIII.

[0036] Figure 14 From Figure 7 The top view of the second heating duct is observed in the direction of arrow XIV.

[0037] Figure 15 This is a front view showing the step of covering the warm air outlet of the first warm air duct with a cover plate.

[0038] Figure 16 This is an enlarged cross-sectional view showing the state in which the warm air outlet of the first warm air duct is covered by the first cover plate.

[0039] Figure 17 From Figure 6 The view from below, taken in the direction of arrow XVII.

[0040] Figure 18 This is an enlarged cross-sectional view showing the state in which the warm air outlet of the second warm air duct is covered by the first cover plate.

[0041] Figure 19 From Figure 6 The top view is viewed in the direction of the arrow XIX.

[0042] Figure 20 This is an enlarged cross-sectional view showing the state in which the warm air outlet of the first warm air duct is covered by the second cover plate.

[0043] Figure 21 This is an enlarged cross-sectional view showing the state where the warm air outlet of the first warm air duct is covered by the third cover plate.

[0044] Explanation of reference numerals in the attached figures

[0045] 1, 2, 1Y, 2Y polarizing films

[0046] The width-direction side edges of 2Y-1 and 2Y-2 stacked polarizing films (polarizing films)

[0047] 5, 5A, 5B Heating air ducts

[0048] 52 Warm air outlet

[0049] 6-bar component

[0050] 7 Cover sheet

[0051] 71 One end of the cover plate

[0052] 72. Opposite ends of the cover plate

[0053] 7a First Covering Sheet

[0054] 7b Second Cover Sheet

[0055] 7c Third Covering Sheet

[0056] 8. Maintenance section

[0057] 9. Calibration Section Detailed Implementation

[0058] In this specification, the numerical range represented by "lower limit X to upper limit Y" means that the lower limit X is above the upper limit Y and the upper limit Y is below the upper limit Y. When multiple numerical ranges are described separately, any lower limit value and any upper limit value can be selected to set "any lower limit value to any upper limit value".

[0059] In this specification, terms such as "first" and "second" are sometimes added at the beginning of the terms, but these prefixes are only for distinguishing the terms and do not have any special meaning such as order or superiority.

[0060] [Polarizers and stacked polarizing films]

[0061] Figure 1 This is a partially omitted top view of the polarizing film 1 of the present invention.

[0062] The polarizing film 1 obtained by the drying method (manufacturing method) of the present invention is in the form of a long strip. This long strip-shaped polarizing film is cut into appropriate shapes for various applications.

[0063] In this invention, the polarizing film that is to be dried (manufactured) is a film that includes a polarizer. Here, a polarizer refers to an optical element that has the property (polarizing characteristic) of allowing light (polarized light) that vibrates only in one specific direction to pass through while blocking light that vibrates in other directions.

[0064] A polarizing film only needs to include a polarizer. Conceptually, the polarizing film of this invention includes a polarizer itself, a film formed by stacking a polarizer and a support film, a protective film, or any other film formed by stacking a polarizer and a support film.

[0065] Figure 2 Therefore Figure 1 A cross-sectional view of polarizing film 1 cut along line II-II.

[0066] Reference Figure 2The polarizing film 1 of one embodiment has a support film 11 and a polarizing plate 12 laminated to one face of the support film. The polarizing plate 12 is composed of a hydrophilic polymer layer colored with a dichroic substance. The hydrophilic polymer layer has polarizing properties.

[0067] Figure 3 FIG. 1B is a cross-sectional view of the polarizing film 1 of another embodiment. The cross-sectional view is obtained by cutting the polarizing film 1 of another embodiment at the same position as the II-II line of FIG. 1A. Figure 1

[0068] Referring to FIG. 1A and FIG. 1B, Figure 3 the polarizing film 1 of another embodiment is composed of a polarizing plate 13 itself. The polarizing plate 13 is composed of a hydrophilic polymer film colored with a dichroic substance. The hydrophilic polymer film has polarizing properties.

[0069] Hereinafter, Figure 2 the polarizing film composed of the support film 11 and the polarizing plate 12 and Figure 3 the polarizing film 1 composed of only the polarizing plate 13 are collectively referred to as a "basic polarizing film 1".

[0070] In addition, a polarizing film in which one or more than two arbitrary films are further laminated to the basic polarizing film 1 can also be used. Hereinafter, the arbitrary film is referred to as an "arbitrary film" and a polarizing film in which an arbitrary film is laminated to the basic polarizing film 1 is collectively referred to as a "laminated polarizing film".

[0071] Figure 4 and Figure 5 FIGS. 2A and 2B are cross-sectional views of several laminated polarizing films 2.

[0072] Referring to FIG. 2A and FIG. 2B, Figure 4 the laminated polarizing film 2 of one embodiment has a basic polarizing film 1 and a first arbitrary film 21, the basic polarizing film 1 has a support film 11 and a polarizing plate 12, and the first arbitrary film 21 is laminated to the polarizing plate 12 of the basic polarizing film 1 via an adhesive layer 211.

[0073] Referring to FIG. 3A and FIG. 3B, Figure 5 the laminated polarizing film 2 of another embodiment has a basic polarizing film 1, a first arbitrary film 21, and a second arbitrary film 22, the basic polarizing film 1 is composed of only a polarizing plate 13, the first arbitrary film 21 is laminated to one face of the basic polarizing film 1 via an adhesive layer 211, and the second arbitrary film 22 is laminated to the opposite face of the basic polarizing film 1 via an adhesive layer 221.

[0074] <Arbitrary Film>

[0075] As the arbitrary film, a protective film, a phase difference film, a brightness improvement film, a transparent conductive film, and the like can be given. The arbitrary film laminated to the basic polarizing film 1 can be appropriately selected from among them.​

[0076] For example, a protective film is used as the first arbitrary film 21. For example, a protective film is used as the second arbitrary film 22. For example, a protective film or a phase difference film is used as the third arbitrary film 23.

[0077] The protective film is a film for protecting a polarizing plate. As described later, the protective film is laminated to a base polarizing film after the base polarizing film is produced.

[0078] The protective film is a film used for the purpose of protecting a polarizing plate or the like as a protected body from damage or contamination. As the protective film, for example, a film made of an olefin-based resin such as polyethylene or polypropylene; an ester-based resin such as polyethylene terephthalate; an amide-based resin such as nylon 6; a vinyl polymer such as polyvinyl chloride or a vinyl chloride-vinyl acetate copolymer; a cellulose-based resin such as triacetyl cellulose or diacetyl cellulose; an acrylic-based resin such as polymethyl methacrylate; a styrene-based resin; a carbonate-based resin; a polyarylate-based resin; an imide-based resin; or the like can be exemplified.

[0079] The phase difference film is an optical film exhibiting optical anisotropy. As the phase difference film, for example, an anisotropic film such as a 1 / 2λ plate or a 1 / 4λ plate can be exemplified.

[0080] The brightness improving film is an optical film that transmits only a specific polarized light and reflects other polarized light.

[0081] <Adhesive Layer>

[0082] The adhesive layer is a cured layer of an adhesive, and is a layer that is interposed between two films and adheres the two films.

[0083] The adhesive layer is constituted by, for example, an active energy ray-curable adhesive such as an ultraviolet-curable adhesive, a solvent evaporation-type adhesive, or the like.

[0084] [Manufacturing Apparatus for Base Polarizing Film and Laminated Polarizing Film]

[0085] The manufacturing apparatus of the present application has a base polarizing film production region that produces a long strip-shaped base polarizing film, and a laminated polarizing film production region that produces a long strip-shaped laminated polarizing film.

[0086] The base polarizing film production region produces a base polarizing film by wet processing a long strip-shaped film raw material. The base polarizing film production region is preferably a system in which a series of processes of wet processing a film raw material and drying the same to obtain a base polarizing film are performed on one production line.

[0087] The laminated polarizing film manufacturing area manufactures the laminated polarizing film by laminating the arbitrary film on the long strip-shaped base polarizing film. The laminated polarizing film manufacturing area is preferably a type in which a series of processes from laminating the arbitrary film on the base polarizing film via the adhesive and drying it to obtain the laminated polarizing film are performed on one production line.

[0088] In addition, the manufacturing apparatus of the present application can be a type in which the base polarizing film manufacturing area and the laminated polarizing film manufacturing area are independent of each other, or a type in which the base polarizing film manufacturing area and the laminated polarizing film manufacturing area are connected together and disposed on one production line.

[0089] Specifically, the manufacturing of the laminated polarizing film can be (a) a type in which the base polarizing film is temporarily wound into a roll after the base polarizing film is manufactured, and the base polarizing film wound into the roll is sent out and laminated and adhered to the arbitrary film, or (b) a type in which the base polarizing film is manufactured, and then the arbitrary film is laminated and adhered to the base polarizing film on one production line. From the viewpoint of manufacturing efficiency, the (b) type is preferable.

[0090] The manufacturing apparatus of the (b) type is a type in which the base polarizing film manufacturing area and the laminated polarizing film manufacturing area are connected together and disposed on one production line (a type in which a series of processes from the base polarizing film to the laminated polarizing film are performed on one production line).

[0091] Figure 6 A preferable configuration example of the manufacturing apparatus 10 of the polarizing film (the base polarizing film and the laminated polarizing film) of the (b) type is shown.

[0092] Referring to Figure 6 , the manufacturing apparatus 10 has at least a conveying apparatus 101 that conveys each film of the film raw material Y, the base polarizing film 1Y, the laminated polarizing film 2Y, and the arbitrary films 21Y, 22Y, a base polarizing film manufacturing area 3, and a laminated polarizing film manufacturing area 4 that adheres at least one film to the base polarizing film 1Y. The conveying apparatus 101 is provided with various rollers such as guide rollers.

[0093] The base polarizing film manufacturing area 3 has a wet treatment apparatus 31 that performs wet treatment on the film raw material Y, and a drying apparatus 32 that dries the base polarizing film 1Y.

[0094] The laminated polarizing film manufacturing area 4 has a laminating apparatus 41 that adheres the arbitrary film to the base polarizing film 1Y obtained by the base polarizing film manufacturing area 3 using an adhesive, and a drying apparatus 42 that dries the laminated polarizing film 2Y to which the arbitrary film is adhered.

[0095] The drying device 32 of the basic polarizing film production area 3 blows warm air against the long strip-shaped basic polarizing film 1Y (polarizing film) while conveying the basic polarizing film 1Y in the longitudinal direction.

[0096] The drying device 42 of the laminated polarizing film production area 4 blows warm air against the long strip-shaped laminated polarizing film 2Y (polarizing film) while conveying the laminated polarizing film 2Y in the longitudinal direction.

[0097] The present application is characterized in that, as a drying device that blows warm air against a polarizing film while conveying the polarizing film in the longitudinal direction, a device having a cover sheet that covers a region in a warm air blowing-out portion of a warm air duct corresponding to an end portion in a width direction of the polarizing film is used.

[0098] The drying device having a cover sheet can be applied to the drying device 32 of the basic polarizing film production area 3, and / or can also be applied to the drying device 42 of the laminated polarizing film production area 4.

[0099] In Figure 6 In the configuration example of the laminated polarizing film production area 4, a case in which the drying device (drying device having a cover sheet) characteristic of the present application is used as the drying device 42 of the laminated polarizing film production area 4 is exemplified.

[0100] <Basic polarizing film production area>

[0101] The basic polarizing film production area 3 has a wet treatment device 31 that obtains a basic polarizing film 1Y by wet treatment of a film raw material Y, and a drying device 32 that dries the basic polarizing film 1Y obtained by the wet treatment.

[0102] The wet treatment device 31 can adopt a configuration known in the past.

[0103] For example, the wet treatment device 31 has, in order from the upstream side, 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. The wet treatment device 31 is not limited to the structure, and for example, the wet treatment device 31 can not have the swelling treatment tank 311, or can not have the stretching treatment tank 314. In the case where the stretching treatment tank 314 is not provided, the film raw material Y is subjected to stretching treatment in the tank such as the dyeing treatment tank 312. In addition, the wet treatment device 31 can have other treatment tanks such as an adjustment treatment tank.

[0104] Note that, in the present specification, the downstream side refers to the conveying direction side of the film (the advancing direction side of the film), and the upstream side refers to the opposite side thereof (the side opposite to the conveying direction of the film).

[0105] The untreated film raw material Y is conveyed to the downstream side of the swelling treatment tank 311 and the like by the conveying device 101 provided with a guide roller and the like. Figure 6 The hollow arrow indicates the advancing direction (conveying direction) of the film.

[0106] The film raw material Y is a long strip shape. In the present specification, the long strip shape means a rectangular shape in which the length in the length direction is sufficiently greater than the length in the width direction (direction orthogonal to the length direction). The length in the length direction of the long strip shape is, for example, 10 m or more, and preferably 50 m or more.

[0107] The film raw material Y can use a long strip-shaped film containing a hydrophilic polymer.

[0108] As the film raw material Y, for example, a laminate composed of a long strip-shaped support film and a hydrophilic polymer layer laminated on one face of the support film or a hydrophilic polymer film can be used. In the case where the laminate is used as the film raw material Y, the basic polarizing film shown in FIG. 1 can be obtained. In the case where the hydrophilic polymer film is used as the film raw material Y, the basic polarizing film shown in FIG. 2 can be obtained. Figure 2 Figure 3

[0109] The film raw material Y can use a conventionally known untreated film.

[0110] Briefly, the hydrophilic polymer layer of the laminate can be formed by applying a coating liquid containing a hydrophilic polymer to one face of a support film and drying the coating liquid. The support film can use a colorless transparent resin film, for example, an ester-based resin film such as a polyethylene terephthalate-based resin, and the like.

[0111] As the hydrophilic polymer, a polyvinyl alcohol (PVA)-based resin, an ethylene-vinyl alcohol copolymer, and the like can be listed.

[0112] The hydrophilic polymer film can be obtained by forming a hydrophilic polymer into a film shape. As the hydrophilic polymer, as described above, a PVA-based resin, an ethylene-vinyl alcohol copolymer, and the like can be listed.

[0113] The swelling treatment tank 311 is a treatment tank in which a swelling liquid is housed. The swelling liquid swells the film raw material Y. As the swelling liquid, for example, water or an aqueous solution containing an iodine compound such as potassium iodide can be used.

[0114] The dyeing treatment tank 312 is a treatment tank in which a dyeing liquid is housed. The dyeing liquid dyes the hydrophilic polymer of the film raw material Y. As the dyeing liquid, 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. As the dichroic substance, iodine, an organic dye, and the like can be listed.

[0115] ​​The cross-linking treatment tank 313 is a treatment tank in which a cross-linking solution is stored. The cross-linking solution cross-links the dyed film raw material 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 a boron compound and an iodine compound such as potassium iodide can be used.

[0116] The stretching treatment tank 314 is a treatment tank in which a stretching solution is stored. The stretching solution can use, for example, an aqueous solution containing a boron compound, and preferably an aqueous solution containing a boron compound and an iodine compound such as potassium iodide. By dyeing and stretching, the film raw material Y becomes the basic polarizing film 1Y.

[0117] The cleaning treatment tank 315 is a treatment tank in which a cleaning solution is stored. The cleaning solution cleans the basic polarizing film 1Y (the dyed and stretched film raw material Y). As the cleaning solution, for example, water or an aqueous solution containing an iodine compound such as potassium iodide, or the like can be used.

[0118] As needed, on the downstream side of the cleaning treatment tank 315, a spray section 316 that blows the cleaning solution against the basic polarizing film 1Y drawn out of the cleaning treatment tank 315, and a blow-off section 317 (liquid breaking section) that removes the cleaning solution adhering to the film can be provided.

[0119] The drying device 32 of the basic polarizing film production area 3 is provided on the downstream side of the cleaning treatment tank 315. The drying device 32 is provided in order to dry the basic polarizing film 1Y after the cleaning treatment. The drying device 32 can be one, or two or more can be arranged in the transport direction of the basic polarizing film 1Y. The drying device 32 is preferably, for example, a type that dries by blowing warm air against the basic polarizing film 1Y. The drying device 32 has, for example, a chamber 321 and a warm air duct (not shown) having a warm air blowing section that blows out warm air, and the warm air duct is disposed in the chamber 321.

[0120] <Stacked Polarizing Film Production Area>

[0121] The stacked polarizing film production area 4 has a laminating device 41 that laminates the basic polarizing film 1Y obtained by the basic polarizing film production area 3 with an arbitrary film using an adhesive, and a drying device 42 that dries the laminated polarizing film 2Y to which the arbitrary film is laminated.

[0122] The laminating device 41 can adopt a configuration known in the art. See, for example, Patent Document 1. Figure 6 The laminating device 41 is briefly described. The laminating device 41 has an adhesive coating section 412, 413 that coats the first arbitrary film 21Y and the second arbitrary film 22Y with an adhesive, and a laminating section 414 that laminates the basic polarizing film 1Y with the arbitrary film. The adhesive coating section can adopt a suitable coater, and for example, a gravure roll can be used as illustrated. The laminating section 414 can use, for example, a nip roll.

[0123] Note that, in the case where the adhesive is a radiation-curable type, a radiation irradiation device 415 is arranged after the bonding section.

[0124] The laminating device 41 of the illustrated example is a double-sided laminating type that bonds the first arbitrary film 21Y and the second arbitrary film 22Y to one face and the opposite face of the base polarizing film 1Y. In the case of using this laminating device 41, for example, the laminated polarizing film illustrated in Figure 5 is obtained. Note that the laminating device 41 can also be a single-sided laminating type that bonds an arbitrary film to only one face of the base polarizing film 1Y. In the case of using the laminating device 41 of this single-sided laminating type, for example, the laminated polarizing film illustrated in Figure 4 is obtained.

[0125] After bonding a surface protective film (not illustrated) to the obtained laminated polarizing film, the laminated polarizing film is wound up.

[0126] [DRYING DEVICE OF THE INVENTION]

[0127] The drying device 42 of the laminated polarizing film production area 4 is provided on the downstream side of the laminating device 41. The drying device 42 is provided in order to dry the laminated polarizing film 2Y (a laminate of a base polarizing film and an arbitrary film). The drying device 42 can be one, or two or more can be arranged in line in the conveying direction of the laminated polarizing film 2Y.

[0128] In the illustrated example, the laminated polarizing film 2Y is conveyed approximately horizontally, and two drying devices 42 are arranged during the conveying thereof.

[0129] The drying device 42 has a warm air duct 5 having a warm air blow-out section arranged so as to oppose the surface of the base polarizing film 1Y, a cover sheet 7 that covers the region in the warm air blow-out section corresponding to the width direction end portion of the laminated polarizing film 2Y, and a chamber 421 as necessary.

[0130] The chamber 421 is a housing that encloses the outside of the warm air duct 5 equipped with the cover sheet 7. The warm air duct 5 is housed in the chamber 421 in a sealed state.

[0131] The cover sheet 7 can use a resin sheet that is soft and has excellent smoothness. The material of the resin sheet is not particularly limited, and examples include a mixture of one or two or more materials selected from the group consisting of polyester-based resins such as polyethylene terephthalate, olefin-based resins such as polypropylene, styrene-based resins such as polystyrene and styrene-butadiene copolymer, cyclic olefin-based resins, vinyl chloride-based resins, vinyl chloride-based copolymers, polyamide-based resins, polyimide-based resins, polycarbonate-based resins, fluororesins, and the like.

[0132] Since the cover sheet 7 is used for the warm air duct 5, the cover sheet 7 is preferably a resin sheet excellent in heat resistance. The resin sheet excellent in heat resistance is, for example, preferably a resin having a glass transition temperature of 100°C or higher, more preferably a resin having a glass transition temperature of 200°C or higher, and examples thereof include a polyimide-based resin sheet, a polycarbonate-based resin sheet, a fluororesin sheet, and the like. Among them, a polyimide-based resin sheet having a glass transition temperature of 216°C is preferable. Note that in the case of using 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, there is a risk that the sheet is elongated or wrinkled due to heat.

[0133] The thickness of the cover sheet 7 is not particularly limited and is, for example, 50 μm to 200 μm.

[0134] The cover sheet 7 is formed in a band shape.

[0135] The lateral width of the cover sheet 7 is not particularly limited, but if it is too small, the cover width of the region corresponding to the widthwise end portion of the laminated polarizing film 2Y (polarizing film) is too small, and if it is too large, the warm air blow-out portion is blocked in a large range, and the blow-out amount of the warm air is excessively limited. From this perspective, the lateral width W7 of the cover sheet 7 is preferably 30 mm to 150 mm, more preferably 50 mm to 100 mm. Note that in the present specification, the lateral width refers to the length in the widthwise direction.

[0136] With regard to the band shape and the lateral width W7 of the cover sheet 7, for example, refer to Figure 17 .

[0137] The warm air ducts 5 each equipped with the cover sheet 7 are disposed on both surfaces (one surface and the opposite surface) of the laminated polarizing film 2Y. In the present specification, the warm air duct 5 disposed on the one surface side of the laminated polarizing film 2Y (polarizing film) is referred to as "first warm air duct 5A", the warm air duct 5 disposed on the opposite surface side of the laminated polarizing film 2Y (polarizing film) is referred to as "second warm air duct 5B", and the whole is collectively referred to as "warm air duct 5".

[0138] The first warm air duct 5A and the second warm air duct 5B can each independently be only one, but it is preferable that two or more be arranged side by side in the lengthwise direction of the laminated polarizing film 2Y, more preferably three or more. Although the upper limit of the number of the first warm air duct 5A and the second warm air duct 5B is not particularly limited, each is, for example, 15 or less, preferably 12 or less.

[0139] In the illustrated example, an example in which three first warm air ducts 5A and three second warm air ducts 5B are arranged side by side in the lengthwise direction for each drying device 42 is illustrated as a reference.

[0140] When multiple first heating air ducts 5A and second heating air ducts 5B are arranged side by side, the spacing between adjacent heating air ducts 5 along the length direction is not particularly limited and can be set appropriately.

[0141] <First Heating Duct>

[0142] Figure 7 This is a front view showing one of each of the first warm air duct 5A and the second warm air duct 5B of the drying device 42. Figure 7 The image shows the first warm air duct 5A and the second warm air duct 5B in the state where the warm air outlet is covered by the cover plate 7 (the state where the cover plate 7 is stored). Figure 7 The thin dashed line represents the transport path of the stacked polarizing film 2Y.

[0143] Figure 8 This is a bottom view of the first heating air duct 5A with the cover plate 7 covering the front of the heating air outlet. Figure 9 This is the left-side view of the first heating air duct, 5A. Figure 10 This is a right-side view of the first heating air duct, 5A. Figure 11 This is a top view of the first heating air duct, 5A. Figure 12 as well as Figure 13 It is an enlarged cross-sectional view of the middle section of the first heating air duct 5A in the width direction, cut along a direction orthogonal to the width direction.

[0144] Note that in Figure 8 to Figure 11 , Figure 14 In the text, the middle part in the width direction that has the same continuous structure is omitted.

[0145] Reference Figure 7 to Figure 13 The first heating air duct 5A is composed of a slender hollow body extending along its width. The slender first heating air duct 5A is configured such that its long axis is approximately parallel to the width direction of the stacked polarizing film 2Y.

[0146] The first heating air duct 5A includes: a heating air outlet 52 having an opening 51 (nozzle); a side portion 53 disposed on one side of the heating air outlet 52; a side portion 54 disposed on the opposite side of the heating air outlet 52; and a top portion 55 disposed between the side portion 53 and the side portion 54. The heating air outlet 52, the side portion 53, the top portion 55, and the side portion 54 are interconnected to form a hollow first heating air duct 5A.

[0147] The warm air blowing part 52 is arranged opposite to the stacked polarizing film 2Y (polarizing film).

[0148] In the warm air blow-out portion 52, an opening portion 51 for blowing out warm air is provided through. The opening portion 51 is provided as a slit-like opening extending in the width direction (the long axis direction of the first warm air duct 5A). The opening portion 51 is formed, for example, in a pair. Note that the opening portion 51 is not limited to an elongated slit-like opening, and can be, for example, a plurality of small holes (not shown) arranged in the width direction. Warm air is supplied from a not-shown warm air supply machine into the first warm air duct 5A, and the warm air is blown out from the warm air blow-out portion 52 toward the stacked polarizing film 2Y through the opening portion 51.

[0149] The outer surface of the warm air blow-out portion 52 is a substantially flat surface except for the opening portion 51.

[0150] The first warm air duct 5A including the warm air blow-out portion 52 is generally formed of a metal such as iron, stainless steel, or the like.

[0151] A cover sheet 7 is provided to the first warm air duct 5A. The cover sheet 7 covers a region in the warm air blow-out portion 52 corresponding to the width direction end portion of the stacked polarizing film 2Y.

[0152] For one first warm air duct 5A, one cover sheet 7 that covers a region in the warm air blow-out portion 52 corresponding to the width direction end portion of the stacked polarizing film 2Y can be provided, but it is preferable that two or more cover sheets 7 be provided to one first warm air duct 5A.

[0153] Here, the lateral width of the stacked polarizing film 2Y (polarizing film) that is the object of drying is various. That is, generally, a manufacturing device 10 is used to manufacture stacked polarizing films 2Y (polarizing films) of various lateral widths. With one manufacturing device 10, for example, it is possible to manufacture stacked polarizing films 2Y (polarizing films) having a lateral width of 500 mm to 4000 mm. Therefore, the drying device 42 is also able to dry stacked polarizing films 2Y of various lateral widths. Generally, the width direction length of the first warm air duct 5A is designed to be larger than the largest lateral width of the stacked polarizing film 2Y (the largest lateral width stacked polarizing film) considering that the largest lateral width stacked polarizing film is to be manufactured. Thus, the region in the warm air blow-out portion 52 corresponding to the width direction end portion of the stacked polarizing film 2Y is different in the case of drying a stacked polarizing film 2Y having a wide width and in the case of drying a stacked polarizing film 2Y having a narrow width. When a stacked polarizing film 2Y having a wide width is transported while being dried, the width direction end portion of the stacked polarizing film 2Y passes on the outer side in the width direction of the warm air blow-out portion 52. When a stacked polarizing film 2Y having a narrow width is transported while being dried, the width direction end portion of the stacked polarizing film 2Y passes at a position on the inner side in the width direction of the warm air blow-out portion 52 than the stacked polarizing film 2Y having a wide width.

[0154] It is desirable to prevent damage to the end portions of the stacked polarizing films 2Y (polarizing films) even in the case where the stacked polarizing films 2Y (polarizing films) are dried while the lateral widths are thus made different. Thus, it is preferable to provide a plurality of cover sheets 7 that cover different regions in the width direction of the warm air blowing portion 52.

[0155] The plurality of cover sheets 7 include, for example, a first cover sheet 7a that covers a region corresponding to a width direction end portion of a first stacked polarizing film (first polarizing film) of a prescribed lateral width, and a second cover sheet 7b that covers a region corresponding to a width direction end portion of a second stacked polarizing film (second polarizing film) that is narrower in width than the first stacked polarizing film. As in the illustrated example, the cover sheets 7 also include a third cover sheet 7c that covers a region corresponding to a width direction end portion of a third stacked polarizing film (third polarizing film) that is narrower in width than the second stacked polarizing film 2Y.

[0156] The first, second, and third stacked polarizing films satisfy the relationship of first stacked polarizing film lateral width > second stacked polarizing film lateral width > third stacked polarizing film lateral width. In the illustrated example, the first warm air duct 5A is provided with the first cover sheet 7a, the second cover sheet 7b, and the third cover sheet 7c corresponding to the stacked polarizing films (polarizing films) having these three lateral widths, and thus damage to the end portions of the stacked polarizing films can be prevented regardless of which stacked polarizing film is being dried. Note that the cover sheets 7 are not limited to cases where they are provided corresponding to stacked polarizing films (polarizing films) having three lateral widths, and four or more cover sheets can be provided corresponding to stacked polarizing films having four or more lateral widths, respectively.

[0157] From another perspective, there are a left and right pair of width direction end portions of the stacked polarizing films. Thus, from the perspective of preventing damage to each of the width direction right and left end portions (both width direction end portions) of the stacked polarizing films, it is preferable that the cover sheets 7 be composed of a left and right pair corresponding to the width direction right and left end portions of one stacked polarizing film (polarizing film) having a prescribed lateral width. In this case, the cover sheets 7 are provided in groups of left and right pairs for one stacked polarizing film (polarizing film) having a prescribed lateral width.

[0158] Thus, in a more preferable mode, the first cover sheet 7a is provided on each of the left and right sides in the width direction of the first warm air duct 5A so as to be able to cover each of the regions corresponding to the width direction right and left end portions of the first stacked polarizing film (first polarizing film).

[0159] The second cover plate 7b is respectively disposed on the left and right sides of the width direction of the first warm air duct 5A, so as to cover the areas corresponding to the right end and the left end of the width direction of the second layered polarizing film (second polarizing film) respectively.

[0160] The third cover plate 7c is respectively disposed on the left and right sides of the width direction of the first warm air duct 5A, so as to cover the area corresponding to the right end and the left end of the width direction of the third layered polarizing film (second polarizing film).

[0161] A pair of first cover plates 7a are positioned on the outermost side in the width direction of the first heating duct 5A, a pair of second cover plates 7b are positioned on the inner side in the width direction than the first cover plates 7a, and a pair of third cover plates 7c are positioned on the inner side in the width direction than the second cover plates 7b.

[0162] The first cover sheet 7a, the second cover sheet 7b, and the third cover sheet 7c (multiple cover sheets 7) are arranged with gaps in the width direction in a manner that does not overlap with each other.

[0163] Furthermore, the cover plate 7 can be installed on the first heating air duct 5A either separately from and independently of it, or partially connected to it. From the perspective of efficiently installing the cover plate 7, it is preferable that one end of the cover plate 7 is fixed to one side of the heating air outlet 52 of the first heating air duct 5A, and the opposite end of the cover plate 7 becomes a free end (see reference). Figure 12 as well as Figure 13 Furthermore, more preferably, a rod member 6 is installed at the opposite end of the cover plate 7, which is the free end. Examples of methods for installing the rod member 6 at the opposite end of the cover plate 7 include using fasteners such as threaded rods, bolts, and nuts.

[0164] The rod component 6 is, for example, a metal cylinder, which can be solid or hollow (tubular). From the perspective of reducing weight and improving workability, the rod component 6 is preferably hollow as shown in the figure. Note that the rod component 6 is not limited to a cylinder, and can also be other shapes such as a square prism.

[0165] like Figure 12 as well as Figure 13 As shown, the cover sheet 7 (the covered sheet 7 in the stored state) covering the front of the warm air blowing part 52 is wrapped around the rod member 6 and held in the holding part 8.

[0166] The holding portion 8 is provided to the side portion of the air-blowing portion 52, that is, the side surface portion 53. The holding portion 8 is fixed to the side surface portion 53 of the first air duct 5A. As a method of fixing the holding portion 8 to the side surface portion 53, there are a mounting method using a fastener such as a threaded rod, a bolt and a nut, welding, and the like. The holding portion 8 is provided with a pair of left and right holding portions. The holding portion 8 has a fixing portion 81 that fixes one end portion of the cover sheet 7 and a receiving portion 82 that holds the rod member 6. The fixing portion 81 is composed of a main rod provided to the holding portion 8 and a sub rod detachably mounted to the main rod. The sub rod is smaller than the main rod. As a method of mounting the sub rod to the main rod, there are a mounting method using a fastener such as a threaded rod, a bolt and a nut, and the like. One end portion of the cover sheet 7 is fixed to the fixing portion 81 of the holding portion 8 by sandwiching the one end portion between the main rod and the sub rod. The receiving portion 82 is open on the vertical direction upper side (the vertical direction is a direction perpendicular to the horizontal direction) and has a substantially U shape in the front view as shown in FIG. 7. The receiving portion 82 is provided at a plurality of positions, and in the illustrated example, is provided at three different positions in the front view. Figure 13

[0167] In detail, the one end portions of the first cover sheet 7a, the second cover sheet 7b and the third cover sheet 7c are fixed to the side portion of the air-blowing portion 52, that is, the side surface portion 53. In the illustrated example, the one end portions of the first cover sheet 7a, the second cover sheet 7b and the third cover sheet 7c are fixed to the fixing portion 81 of the holding portion 8. Thus, the one end portions of the first cover sheet 7a, the second cover sheet 7b and the third cover sheet 7c are fixed to the side surface portion 53 via the holding portion 8.

[0168] The opposite end portions of the first cover sheet 7a, the second cover sheet 7b and the third cover sheet 7c are free ends. The rod members 6 are mounted to the opposite end portions of the first cover sheet 7a, the second cover sheet 7b and the third cover sheet 7c, respectively. The both end portions of the rod members 6 are made large in diameter for easy gripping.

[0169] The pair of left and right first cover sheets 7a are wound around the rod members 6 mounted to the opposite end portions thereof. The rod members 6 wound with the first cover sheets 7a are placed on the receiving portions 82 of the holding portion 8 and held to the holding portion 8.

[0170] The pair of left and right second cover sheets 7b are wound around the rod members 6 mounted to the opposite end portions thereof. The rod members 6 wound with the second cover sheets 7b are placed on the other receiving portions 82 of the holding portion 8 and held to the holding portion 8.

[0171] The pair of left and right third cover sheets 7c are wound around the rod members 6 mounted to the opposite end portions thereof. The rod members 6 wound with the third cover sheets 7c are placed on the further receiving portions 82 of the holding portion 8 and held to the holding portion 8.

[0172] ​On the other hand, a clamping portion 9 capable of clamping the stick member 6 is provided on the opposite side portion of the warm air blow-out portion 52, that is, the other side surface portion 54. The clamping portion 9 is fixed to the other side surface portion 54 of the first warm air duct 5A. As a method of fixing the clamping portion 9 to the other side surface portion 54, a mounting method using a fastener, welding, or the like can be cited. The clamping portion 9 is provided with a pair of left and right clamping portions in the width direction. The clamping portion 9 has a groove portion 91 that receives the stick member 6 and a cylindrical portion 92 that contacts the cover sheet 7. The groove portion 91 is open on the vertical direction upper side (the vertical direction is a direction perpendicular to the horizontal direction) and is substantially U-shaped in the front view as shown in Figure 13 The cylindrical portion 92 extends in the width direction. The cylindrical portion 92 can be fixedly provided to the clamping portion 9, or can be supported by the clamping portion 9 in a rotatable state. It is preferable that the cylindrical portion 92 be provided in a rotatable state.

[0173] The groove portion 91 is disposed close to the other side surface portion 54, and the cylindrical portion 92 is disposed outside the groove portion 91.

[0174] Note that the holding portion 8 and the clamping portion 9 are, for example, made of metal.

[0175] <Second Warm Air Duct>

[0176] Figure 14 is a plan view of the second warm air duct 5B in a state in which the warm air blow-out portion 52 is covered by the cover sheet 7.

[0177] Referring to Figure 7 and Figure 14 , like the first warm air duct 5A, the second warm air duct 5B is composed of an elongated hollow body extending in the width direction, and has a warm air blow-out portion 52 disposed opposite a laminated polarizing film (polarizing film).

[0178] Comparing the Figure 7 and Figure 14 of the second warm air duct 5B with the Figure 7 to Figure 13 of the first warm air duct 5A, it is clear that the second warm air duct 5B: (a) has the warm air blow-out portion 52 disposed on the vertical direction upper side; and (b) is not provided with a clamping portion 9. The details of the second warm air duct 5B are the same as those of the above-mentioned <First Warm Air Duct> column except for the above-mentioned (a) and (b). Therefore, the description of the second warm air duct 5B will be given by replacing "first warm air duct 5A" in the above-mentioned <First Warm Air Duct> column with "second warm air duct 5B", which is a specific example of the second warm air duct 5B.

[0179] Note that a clamping portion (not shown) that clamps the stick member 6 can also be provided on the other side surface portion 54 of the second warm air duct 5B.

[0180] <First Warm Air Duct and Second Warm Air Duct with Warm Air Blow-out Portion Covered by Cover Sheet>

[0181] As mentioned above, Figure 7 to Figure 13 The first heating duct 5A shown and Figure 7 as well as Figure 14 The second warm air duct 5B shown is not covered by the cover plate 7 at the warm air outlet 52; the cover plate 7 is held in the holding part 8. That is, the first warm air duct 5A and the second warm air duct 5B are in the state before the drying device 42 is operated, and in the state before the cover plate 7 is installed. When the drying device 42 is operated, the cover plate 7 covers the area in the warm air outlet 52 of the first warm air duct 5A corresponding to the width direction end of the stacked polarizing film 2Y (polarizing film). Similarly, the cover plate 7 covers the area in the warm air outlet 52 of the second warm air duct 5B corresponding to the width direction end of the stacked polarizing film 2Y (polarizing film).

[0182] Figure 15 This is a front view showing the step of covering the warm air outlet 52 of the first warm air duct 5A with the cover plate 7.

[0183] Such as Figure 15 As shown in (a), the cover sheet 7 is removed from the holding part 8. In the example shown, the removal of the first cover sheet 7a is illustrated. Since the rod member 6 is mounted at the opposite end of the cover sheet 7, the cover sheet 7 is wound around the rod member 6. Therefore, the rod member 6 is removed from the holding part 8, and the cover sheet 7 is pulled out while being released from the rod member 6. Since one end of the cover sheet 7 is fixed to the holding part 8, the pulled-out cover sheet 7 will not detach from the first warm air duct 5A. Next, as shown... Figure 15 As shown in (b), while the cover plate 7 is mounted on the warm air outlet 52, it is reversed at the cylindrical portion 92 of the locking portion 9. Finally, as shown in (b), Figure 15 As shown in (c), the rod member 6 is inserted into the slot 91 of the locking part 9. The cover plate 7 extends from the holding part 8 (one side of the warm air outlet 52) ​​to the locking part 9 (the opposite side of the warm air outlet 52) ​​and is mounted on the part including the warm air outlet 52.

[0184] By simply removing the rod component 6 from the retaining part 8 and locking the rod component 6 in the locking part 9, the cover plate 7 can be installed on the warm air outlet part 52 with extreme ease.

[0185] Figure 16 This is an enlarged cross-sectional view showing the state in which the first cover plate 7a is installed in the warm air outlet 52 of the first warm air duct 5A. Figure 16 It is also to Figure 15 Enlarged cross-sectional view of the first warm air duct 5A in state (c) cut at the longitudinal section position of the cover plate 7. Figure 16 The thin dashed line represents the transport path of the stacked polarizing film 2Y.

[0186] Referring to Figure 16 , the stick member 6 inserted into the slot portion 91 is in a suspended state. The one end portion 71 of the cover sheet 7 is fixed to the one side portion of the air-blowing portion 52, that is, the one side surface portion 53 (the holding portion 8), and, since the stick member 6 mounted to the opposite end portion 72 of the cover sheet 7 is in a suspended state, the cover sheet 7 is in a state in which a tension is applied thereto due to the weight of the stick member 6. In particular, the cover sheet 7 is applied with the tension, and thus is tightly attached to the air-blowing portion 52. In this way, the cover sheet 7 covers the region of the air-blowing portion 52 in a tensioned state, and thus the cover sheet 7 is difficult to be separated from the air-blowing portion 52. As a method of making the cover sheet 7 be in a tensioned state when covering the region of the air-blowing portion 52, for example, a method of pulling the cover sheet 7 using a spring or the like elastic member can be employed. In this regard, as described above, if the method of applying the tension to the cover sheet 7 by the weight of the stick member 6 (the weight of the stick member 6) is employed, the configuration is extremely simple. In addition, the stick member 6 can be used as an operation portion when the cover sheet 7 is taken out of the holding portion 8 or the cover sheet 7 is stored in the holding portion 8.

[0187] Figure 17 is a plan view of the first air-blowing duct 5A in which the first cover sheet 7a is disposed in the state of being observed from the vertical direction. Figure 17 is a plan view of the first air-blowing duct 5A in which the first cover sheet 7a is disposed in the state of being observed from the vertical direction. Figure 6 is a plan view of the first air-blowing duct 5A in which the first cover sheet 7a is disposed in the state of being observed from the vertical direction. Figure 17 Note that, in Figure 19 to Figure 21 , the width direction middle portions (also the same) which are continuously the same configuration are omitted.

[0188] Referring to Figure 17 , the cover sheet 7 covers the region in the air-blowing portion 52 corresponding to the width direction end portion of the laminated polarizing film 2Y (polarizing film). In this drawing, the width direction both side edges 2Y-1, 2Y-2 of the laminated polarizing film 2Y (polarizing film) are indicated by a broken line, that is, a double-dotted line. Note that the width direction end portion of the laminated polarizing film 2Y (polarizing film) refers to the side edge vicinity portion including the width direction side edge.

[0189] It is preferable that the cover sheet 7 be arranged in such a manner that the width direction side edge of the laminated polarizing film 2Y is located at the substantially central portion in the width direction of the cover sheet 7. The one end portion of the cover sheet 7 is fixed in this arrangement.

[0190] In the illustrated example, the first cover sheets 7a arranged at the outermost sides cover the regions corresponding to the width direction both end portions of the laminated polarizing film 2Y, respectively. The first cover sheets 7a are cover sheets 7 arranged so as to be able to cover the regions corresponding to the width direction both end portions of the first laminated polarizing film (first polarizing film), respectively. Therefore, Figure 17is an example of a case where the first laminated polarizing film is dried with the widest width. Note that the lateral width W1 of the first laminated polarizing film is the length between the widthwise side edges.

[0191] Since the area of the warm air blow-out portion 52 is covered by the first cover sheet 7a, even if the widthwise end portion of the first laminated polarizing film is curled when the first laminated polarizing film is dried while being conveyed on one side, it does not directly contact the warm air blow-out portion 52. Since the end portion of the first laminated polarizing film is in contact with the cover sheet 7 even if it is curled, damage to the end portion can be prevented.

[0192] Figure 18 is an enlarged cross-sectional view showing the state where the first cover sheet 7a is arranged at the warm air blow-out portion 52 of the second warm air duct 5B. Figure 18 The thin dotted line of

[0193] Referring to Figure 18 For the second warm air duct 5B, as with the first warm air duct 5A, the rod member 6 is detached from the holding portion 8, the area of the warm air blow-out portion 52 is covered with the first cover sheet 7a, and the rod member 6 is taken to the other side face portion 54. By simply moving the rod member 6 to the other side face portion 54 like this, the cover sheet 7 can be arranged at the warm air blow-out portion 52 extremely easily. In the illustrated example, a case where the first cover sheet 7a is arranged is illustrated.

[0194] For the second warm air duct 5B, as with the first warm air duct 5A, the cover sheet 7 covers the area of the warm air blow-out portion 52 in a state where tension is applied due to the weight of the rod member 6.

[0195] Figure 19 is a bottom view of the second warm air duct 5B viewed from the vertical direction, showing the state where the first cover sheet 7a is arranged at the warm air blow-out portion 52. Figure 19 is a view of Figure 6 from the direction of arrow XIX.

[0196] Referring to Figure 19 For the second warm air duct 5B, as with the first warm air duct 5A, the cover sheet 7 covers the area in the warm air blow-out portion 52 corresponding to the widthwise end portion of the laminated polarizing film 2Y (polarizing film). In this drawing, the widthwise side edges 2Y-1, 2Y-2 of the laminated polarizing film 2Y (polarizing film) are indicated by a broken line, i.e., a double-dotted line.

[0197] It is preferable to arrange the cover sheet 7 in such a manner that the widthwise side edges of the laminated polarizing film 2Y are positioned at the approximately central portions in the widthwise direction of the cover sheet 7. One end portion of the cover sheet 7 is fixed in this arrangement.

[0198] In the example shown, the first cover plate 7a, which is positioned on the outermost side, covers the regions corresponding to the two ends of the stacked polarizing film 2Y in the width direction.

[0199] The second warm air duct 5B, which is also the area of ​​the warm air outlet 52, is covered by the first cover plate 7a. Therefore, even if its width-direction end curls while the first layered polarizing film is being transported and dried, it will not directly contact the warm air outlet 52. Thus, damage to the ends of the first layered polarizing film can be prevented.

[0200] [Manufacturing methods of basic polarizing films and stacked polarizing films]

[0201] <The process of covering the warm air outlet with a cover plate>

[0202] Before operating the drying device 42, from Figure 7 Take out the prescribed cover plate 7 from the first heating air duct 5A and the second heating air duct 5B as shown, and install it on the heating air outlet 52. For the steps of covering the heating air outlet 52 with the cover plate 7 and the structure of the first heating air duct 5A and the second heating air duct 5B after covering with the cover plate 7, please refer to the above section "First heating air duct and second heating air duct covered with cover plate".

[0203] For example, such as Figure 16 to Figure 19 As shown, a first heating duct 5A and a second heating duct 5B are prepared to be covered by a first cover sheet 7a, which covers the regions corresponding to the two ends of the width direction of the first stacked polarizing film.

[0204] <Manufacturing Processes of Basic Polarizing Films and Stacked Polarizing Films>

[0205] The manufacturing apparatus 10, which has a drying device 42 with a cover plate 7 installed, is operated to manufacture a basic polarizing film and a laminated polarizing film.

[0206] The fabrication of basic polarizing films and the fabrication of stacked polarizing films can be carried out using methods known in the past. A brief explanation follows.

[0207] Reference Figure 6 The untreated membrane material Y is pulled out from the feeding section and conveyed to the swelling treatment tank 311 by the conveying device 101, causing the membrane material Y to swell. Afterwards, the membrane material Y is dyed in the dyeing treatment tank 312 and then crosslinked in the crosslinking treatment tank 313. The crosslinked membrane material Y is then conveyed and stretched in the stretching liquid in the stretching treatment tank 314. After the dyed and stretched membrane material Y is washed in the cleaning treatment tank 315, it is dried using the drying device 32 to obtain the basic polarizing film 1Y.

[0208] An arbitrary film is stacked on the obtained long strip-shaped basic polarizing film 1Y.

[0209] like Figure 6 As shown, adhesive is applied to one side of a strip-shaped first arbitrary film 21Y (e.g., a protective film) using adhesive coating section 412. Adhesive is applied to one side of a strip-shaped second arbitrary film 22Y (e.g., a protective film) using adhesive coating section 413. They are then bonded to one side and the opposite side of a basic polarizing film 1Y and passed through a clamping roller. The adhesive in the laminated body is then cured. In the case of using an active energy ray curable adhesive, the adhesive is irradiated with active energy rays to cure it, resulting in a laminated polarizing film 2Y composed of a first arbitrary film / adhesive layer / basic polarizing film / adhesive layer / second arbitrary film.

[0210] <Drying Process>

[0211] The laminated polarizing film 2Y is introduced into the drying apparatus 42. Inside the drying apparatus 42, warm air is blown out from the warm air outlets 52 of the first warm air duct 5A and the second warm air duct 5B. The airflow and temperature of the warm air are not particularly limited and can be the same as those known in the past. While the laminated polarizing film 2Y (polarizing film) is conveyed along its length through the warm air outlets 5A and 5B covered by the cover sheet 7, the laminated polarizing film 2Y is dried. The warm air from the first warm air duct 5A is blown, for example, in a direction approximately orthogonal to one side of the laminated polarizing film 2Y, and the warm air from the second warm air duct 5B is blown, for example, in a direction approximately orthogonal to the opposite side of the laminated polarizing film 2Y. After drying by blowing warm air, the laminated polarizing film 2Y is wound up.

[0212] Although warm air is used to dry the stacked polarizing film 2Y, the ends of the stacked polarizing film 2Y in the width direction curl up during this process. In particular, the stacked polarizing film 2Y (polarizing film) is prone to end curling during drying because it contains polarizers.

[0213] Previously, the curled end contacted the uneven warm air outlet, damaging the end of the polarizing film and slightly scraping off the film, creating film residue. This led to a vicious cycle where the residue accumulated in the warm air outlet and adhered to the curled end.

[0214] In this regard, according to the present invention, the region in the warm air outlet 52 corresponding to the width direction end of the stacked polarizing film 2Y (polarizing film) is covered by the cover sheet 7, so that the curled end contacts the surface of the cover sheet 7. Since the surface of the cover sheet 7 has excellent smoothness, the end of the stacked polarizing film 2Y is difficult to be damaged, and it is also possible to prevent the formation of film slag caused by the polarizing film.

[0215] Figure 16 to Figure 19The case where the first layered polarizing film is manufactured and dried is shown, and in the case where a layered polarizing film having a lateral width different from that is manufactured, the cover sheet 7 is replaced.

[0216] Specifically, for the first heater duct 5A, the first cover sheet 7a is removed in the reverse of the steps described above, and the first cover sheet 7a is temporarily returned to the state shown in FIG. 7A. Next, the second cover sheet 7b is removed, and the second cover sheet 7b is installed on the heater blow-out portion 52 of the first heater duct 5A in accordance with the steps described in FIG. 7B. For the second heater duct 5B, the same as the first heater duct 5A, the first cover sheet 7a is replaced with the second cover sheet 7b. Figure 15 Figure 8 to Figure 13 Specifically, for the first heater duct 5A, the first cover sheet 7a is removed in the reverse of the steps described above, and the first cover sheet 7a is temporarily returned to the state shown in FIG. 7A. Next, the second cover sheet 7b is removed, and the second cover sheet 7b is installed on the heater blow-out portion 52 of the first heater duct 5A in accordance with the steps described in FIG. 7B. For the second heater duct 5B, the same as the first heater duct 5A, the first cover sheet 7a is replaced with the second cover sheet 7b. Figure 15

[0217] Figure 20 FIG. 8A is a plan view of the first heater duct 5A viewed from the vertical direction in the state where the second cover sheet 7b is installed on the heater blow-out portion 52.

[0218] Referring to FIG. 8B, the second cover sheet 7b covers the region in the heater blow-out portion 52 corresponding to the widthwise end portion of the second layered polarizing film. In this figure, the widthwise both edges of the layered polarizing film (polarizing film) are indicated by dotted lines, i.e., double-dot chain lines. The lateral width W2 of the second layered polarizing film is smaller than the lateral width Wl of the first layered polarizing film. Figure 20 The first heater duct 5A and the second heater duct 5B covered by the second cover sheet 7b are prepared, and the second layered polarizing film is conveyed while being dried, whereby for the second layered polarizing film as well, damage to the widthwise end portion can be prevented.

[0219] Similarly, the third cover sheet 7c can also be installed on the heater blow-out portion 52 of the first heater duct 5A and the second heater duct 5B.

[0220]

[0221] FIG. 9A is a plan view of the first heater duct 5A viewed from the vertical direction in the state where the third cover sheet 7c is installed on the heater blow-out portion 52. Figure 21 Referring to FIG. 9B, the third cover sheet 7c covers the region in the heater blow-out portion 52 corresponding to the widthwise end portion of the third layered polarizing film. The lateral width W3 of the third layered polarizing film is smaller than the lateral width W2 of the second layered polarizing film.

[0222] Figure 21 The first heater duct 5A and the second heater duct 5B covered by the third cover sheet 7c are prepared, and the third layered polarizing film is conveyed while being dried, whereby for the third layered polarizing film as well, damage to the widthwise end portion can be prevented.

[0223] The first heater duct 5A and the second heater duct 5B covered by the third cover sheet 7c are prepared, and the third layered polarizing film is conveyed while being dried, whereby for the third layered polarizing film as well, damage to the widthwise end portion can be prevented.

[0224] ​​​The drying method of the present application is a method in which two or more cover sheets 7 (first cover sheet 7a, second cover sheet 7b, third cover sheet 7c) are provided on the first warm air duct 5A and the second warm air duct 5B, and the area of the warm air blow-out portion 52 is covered with a cover sheet 7 selected from among these cover sheets 7, in accordance with the stacked polarizing film (polarizing film) that differs in lateral width.

[0225] Thus, according to the drying method and the drying apparatus of the present application, it is possible to dry stacked polarizing films (polarizing films) having various lateral widths, and it is possible to prevent damage to the end portions thereof.

[0226] In addition, since a plurality of cover sheets 7 are provided on the warm air duct 5 in correspondence with the type (difference in lateral width) of the stacked polarizing film that is the drying target, it is possible to easily perform replacement of the cover sheets 7.

[0227] In particular, since one end portion of the cover sheet 7 is fixed and a rod member 6 is attached to the opposite end portion, it is possible to perform installation and storage of the cover sheet 7 by operating the rod member 6. Thus, it is possible to easily perform the replacement work of the cover sheet 7.

[0228] [Modified Example]

[0229] Note that the above-described drying apparatus 42 is provided with the first warm air duct 5A and the second warm air duct 5B in correspondence with the stacked polarizing film 2Y that is conveyed in a substantially horizontal direction (in other words, the conveyance path of the polarizing film is substantially horizontal). However, the present application is not limited to the case in which the first warm air duct 5A and the second warm air duct 5B are provided for a polarizing film that is conveyed in a substantially horizontal direction, and for example, the first warm air duct 5A and the second warm air duct 5B can be provided for a polarizing film that is conveyed in a meandering manner, or the first warm air duct 5A and the second warm air duct 5B can be provided for a polarizing film that is conveyed in a direction inclined with respect to the vertical direction or the horizontal direction.

[0230] [Use of Polarizing Film, etc.]

[0231] The polarizing film (base polarizing film and stacked polarizing film) of the present application is typically used as an optical film for a display such as a liquid crystal display device or an organic display device.

[0232] In addition, the polarizing film of the present application is not limited to use in the aforementioned display, and can be used for uses other than displays. As uses other than displays, optical equipment, buildings, the medical / food field, and the like can be cited. In the case in which the polarizing film is used in optical equipment, the polarizing film is, for example, processed into a polarizing lens, a transparent electric wave blocking film, or the like. In the case in which the polarizing film is used in electronic devices, the polarizing film is, for example, processed into a film for a light control window, or the like. In the case in which the polarizing film is used in the medical / food field, the polarizing film is, for example, processed into a light degradation preventing film, or the like.

Claims

1. A drying apparatus for a polarizing film, wherein warm air is blown onto the polarizing film during the process of conveying the long strip-shaped polarizing film along its length, characterized in that, has: a warm air duct having a warm air blow-out portion disposed opposite a surface of the polarizing film; a cover sheet covering a region in the warm air blow-out portion corresponding to a widthwise end portion of the polarizing film, one end portion of the cover sheet is fixed to one side portion of the warm air blow-out portion of the warm air duct, and an opposite end portion of the cover sheet is provided as a free end, a rod member is installed at the opposite end portion of the cover sheet, and a clamping portion capable of clamping the rod member is provided at an opposite side portion of the warm air blow-out portion of the warm air duct, the cover sheet covers the region in a state in which tension is applied thereto by clamping the rod member in the clamping portion, the rod member is made of metal.

2. The drying apparatus for a polarizing film according to claim 1, wherein the cover sheet has two or more pieces, a first cover sheet covers a region corresponding to a widthwise end portion of a first polarizing film, a second cover sheet covers a widthwise end portion of a second polarizing film having a width narrower than the first polarizing film.

3. The drying apparatus for a polarizing film according to claim 1, wherein the cover sheet has two or more pieces, a first cover sheet covers a region corresponding to a widthwise end portion of a first polarizing film, a second cover sheet covers a widthwise end portion of a second polarizing film having a width narrower than the first polarizing film.

4. The drying apparatus for a polarizing film according to claim 1, wherein the cover sheet is composed of a pair of left and right pieces so as to cover regions corresponding to both widthwise end portions of the polarizing film, respectively.

5. The drying apparatus for a polarizing film according to claim 1, wherein the cover sheet includes a polyimide-based resin sheet.

6. A method for drying a polarizing film, wherein the polarizing film is dried during the process of conveying a long strip of polarizing film along its length direction, characterized in that, has: a warm air duct having a warm air blow-out portion disposed opposite a surface of the polarizing film; a cover sheet covering a region in the warm air blow-out portion corresponding to a widthwise end portion of the polarizing film, one end portion of the cover sheet is fixed to one side portion of the warm air blow-out portion of the warm air duct, and an opposite end portion of the cover sheet is provided as a free end, a rod member is installed at the opposite end portion of the cover sheet, and a clamping portion capable of clamping the rod member is provided at an opposite side portion of the warm air blow-out portion of the warm air duct, the cover sheet covers the region in a state in which tension is applied thereto by clamping the rod member in the clamping portion.

7. The drying method for a polarizing film according to claim 6, wherein the warm air duct is provided with two or more pieces of the cover sheet, according to polarizing films differing in lateral width, a cover sheet selected from among the two or more pieces of the cover sheet is used to cover the region.

8. A method for manufacturing a polarizing film, a dried polarizing film being obtained by performing the drying method of claim 6 or 7.

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