TW201919979A - Conveying method and conveying apparatus for film, manufacturing method and manufacturing apparatus for processed film - Google Patents

Abstract

The present invention provides a conveying method for film capable of reducing deviation of rotational speed between a pair of rollers. The conveying method for film of the present invention has a nip rollers conveying step in which a film is conveyed by rotation of a nip roller equipped with a first roller and a second roller opposed to each other; wherein, the nip rollers conveying step including a first roller rotating step in which a rotational force is applied to the first roller from the first driving source to rotate the first roller, and a second roller rotating step in which the second roller is rotated, and in the second roller rotating step, a rotational force is applied to the second roller from the second driving source.

Description

   Method and device for conveying film, and method and device for processing film   

The present invention relates to a film transfer method and a transfer device, and a method and a manufacturing device for processing a film.

The conveying device that continuously supplies the film and continuously conveys the film while contacting the plurality of rollers through a predetermined conveying route is generally a film conveying device. The various rollers used in the conveying device include a guide roller supporting only one side of the film, and a nip roller disposed on both sides of the film and supporting the film from both sides. Here, the nip roller is used for the purpose of adjusting the tension of the film, conveying the film, and applying a pressing force to the film.

For example, Japanese Patent Application Laid-Open No. 2017-76107 (Patent Document 1) discloses a transport device for an optical film including a nip roll.

    [Prior technical literature]         [Patent Literature]    

[Patent Document 1] Japanese Patent Laid-Open No. 2017-76107

Conventionally, in a film conveying device, when a film passes between a pair of rollers, a defect that the surface of the film is scratched occurs. Although there are differences in the degree of scratches on the surface of the film depending on the type, thickness, moisture content, and transport speed of the film being transported, such defects will reduce the yield of the product and also become the inside of the device. The cause of pollution. In particular, if the film is an optical film used in optical applications, due to the demand for a high-quality film, a solution to such a defect becomes a problem.

The present inventors have discovered that one of the causes of the defect that the film surface is scratched when the film is passed between a pair of rollers is that the rotation speed between the pair of rollers varies. An object of the present invention is to provide a film conveying method and a conveying device capable of reducing a variation in the rotation speed between a pair of rollers, and a method and a producing device for a treated film.

The present invention provides a method and a device for conveying a film described below, and a method and a device for producing a processed film.

[1] A film conveying method comprising a nip roller conveying step for conveying a film by rotation of a nip roller including a first roller and a second roller facing each other. The nip roller conveying step includes driving from a first drive. In the second roller rotation step, the first roller rotation step of rotating the first roller by applying a rotational force to the first roller, and the second roller rotation step of rotating the second roller, are performed in the second roller rotation step. The 2 driving source applies a rotational force to the second roller.

[2] The method for conveying a film according to [1], wherein in the second roller rotation step, the second roller rotates as the first roller rotates, and is further provided from a second drive source Rotational force.

[3] The method for transporting the film according to [1] or [2], wherein the rotational force imparted to the second roller from the second driving source in the second roller rotation step is smaller than that of the first roller In the rotating step, a rotating force is applied to the first roller from the first driving source.

[4] The film transport method according to any one of [1] to [3], wherein the film-based optical film or a raw film thereof.

[5] A film conveying device including a first roller and a second roller facing each other, and a nip roller that conveys the film by rotation, and a first driving source that imparts a rotational force to the first roller , And a second drive source that imparts rotational force to the second roller.

[6] The film transporting device according to [5], wherein the film-based optical film or a raw film thereof.

[7] A method for producing a treated film, comprising: a processing step of applying a treatment to a raw film to obtain a treated film; and a method for transporting the film according to any one of [1] to [3], A transport step for transporting the raw material film or the process film.

[8] The method for producing a treatment film according to [7], wherein the treatment film is an optical film.

[9] A device for manufacturing a processing film, comprising: a processing unit that applies processing to a raw film to obtain a processed film; and a device for transferring the raw film or the processed film by the film transfer device described in [5] Transport Department.

[10] The apparatus for manufacturing a processing film according to [9], wherein the processing film is an optical film.

By using the film conveying method of the present invention, the deviation in the rotation speed between a pair of rollers can be reduced.

1‧‧‧ film

5‧‧‧ delivery device

6‧‧‧Guide roller

7‧‧‧ pinch roller

8‧‧‧Control device

10‧‧‧ raw film

11‧‧‧ raw material roll

13‧‧‧Swelling bath

15‧‧‧ Dyeing bath

17a‧‧‧The first cross-linking bath

17b‧‧‧ 2nd Crosslinking Bath

19‧‧‧washing bath

21‧‧‧ drying furnace

23‧‧‧Polarizing Film

30 to 48, 60, 61‧‧‧ guide rollers

50 to 55‧‧‧ nip rollers

71‧‧‧The first roller

72‧‧‧ 2nd roller

71a, 72a ‧‧‧ contact area

71b, 72b‧‧‧Transportation area

A‧‧‧ transport device

FIG. 1 is a cross-sectional view schematically showing an example of a conveyance device for an optical film of the present invention.

FIG. 2 is a perspective view of a nip roller portion in the conveying device shown in FIG. 1. FIG.

Figure 3 is a sectional view taken along the line X-X in Figure 2.

FIG. 4 is a cross-sectional view schematically showing an example of an apparatus for manufacturing a polarizing film of the present invention.

FIG. 5 is a graph plotting the measurement results of the rotation speeds of the first roller and the second roller in Example 1. FIG.

FIG. 6 is a graph plotting the measurement results of the rotation speeds of the first roller and the second roller in Example 2. FIG.

[Transfer method of film]

The film conveying method of the present invention includes a nip conveying step of conveying a film by rotation of a nip roller including a first roller and a second roller facing each other. The nip roller is composed of a first roller and a second roller which are arranged on both sides of the film to be conveyed. The nip rollers perform the function of conveying the film by rotation. In addition to this function, it can also perform the functions of adjusting the tension of the film, applying a pressing force to the film, controlling the speed of the film, and controlling the direction of the film.

The nip roller conveying step includes a first roller rotating step of applying a rotational force to the first roller from the first driving source to rotate the first roller, and a second roller rotating step of rotating the second roller. In the second roller rotation step, a rotational force is applied to the second roller from the second drive source.

In this specification, the meaning of the first drive source and the second drive source is an electric drive source such as a motor, which means a drive source that generates rotational force from electric energy. The film conveying method of the present invention is a film conveying device that uses a film conveying device that each includes a first driving source that applies a rotational force to a first roller and a second driving source that applies a rotational force to a second roller. .

In the film conveying method of the present invention, a rotational force is applied to the first roller from the first driving source. Then, a rotational force is applied to the second roller from the second driving source. In this way, by applying a rotational force to the first roller and the second roller from the respective driving sources, the rotation speeds of the first roller and the second roller can be individually controlled, and thus the rotation speed can be reduced. Deviation of the rotation speed between the 1 roller and the 2 roller. In addition, when the film is conveyed while being sandwiched between the first roller and the second roller, the occurrence of a scratch on the film surface can be reduced.

In the second roller step, the second roller is preferably controlled so as to rotate with the rotation of the first roller. That is, it is preferable that the second roller is controlled not only to be given a rotational force from the second driving source, but also to be given a rotational force by the rotation of the first roller. In the second roller, it is preferable that the second roller is controlled to adjust the deviation from the rotation speed of the first roller by the rotational force given from the second driving source. In this way, the rotation of the first roller is used in the rotation of the second roller, whereby the rotation force imparted to the second roller from the second driving source in the second roller rotation step can be set smaller than that in the first roller. In the one-roller rotation step, the rotational force imparted to the first roller from the first driving source can improve the energy utilization efficiency.

In the nip roller, assuming that the rotation speed of the first roller is V1 and the rotation speed of the second roller is V2, it is calculated by the following formula: R (%) = [(V1-V2) / V1] × 100 The smaller the value of the rotation speed difference ratio R is, the smaller the deviation of the rotation speed generated between the first roller and the second roller is, so the better. The R value is preferably 0.2% or less, more preferably 0.1% or less, and even more preferably 0.05% or less.

In the second roller rotation step, it is preferable to control the second roller to rotate in accordance with the rotation of the first roller, and to apply a rotational force to the second roller by a second driving source. The rotation speed of the second roller is controlled so as to approach the rotation speed of the first roller. For example, in the first roller rotation step, the rotational force applied to the first roller from the first driving source is set to T1, and in the second roller rotation step, the second roller is applied to the second roller. When the rotation force is set to T2, for example, T2 in the range of 0.01T1 to 0.6T1 is applied from the second driving source to the second roller in the second roller rotation step, so that the second roller can be The rotation speed is close to the rotation speed of the first roller.

The rotation speed of the first roller and the second roller can be measured by a measuring device. As for the measuring device, for example, a rotary encoder may be used. The rotary encoder detects a rotation displacement amount of a rotating shaft of a roller by a contact type or a non-contact type, and outputs a pulse train according to the rotation displacement amount.

The rotational force generated by the rotation of the first roller can be applied to the second roller through the film being transported. From the viewpoint that the rotational force generated by the rotation of the first roller can be more effectively imparted to the second roller, the first roller and the second roller preferably have the first roller and the second roller. A contact area where the outer peripheral surface of the roller is in direct contact without a film interposed therebetween.

In the nip roller, the positional relationship between the first roller and the second roller is not limited, but the two rollers are arranged at different positions in the vertical direction, and the rotational force is given to the first roller from the first driving source. When the rotational force is greater than the rotational force imparted to the second roller from the second drive source, the roller located on the lower side in the vertical direction may be more suitable as the first roller. For example, in the nip roller, if an air cylinder is used to push the roller located on the upper side of the vertical direction to the roller located on the lower side of the vertical direction, because the air cylinder is provided on the roller located on the upper side of the vertical direction, Therefore, it is susceptible to external interference such as changes in injection pressure or changes in set pressure. If such a servo motor, which is susceptible to external interference, is used as the driving source of the roller located on the upper side in the vertical direction, it will be difficult to accurately control the rotation speed of the roller, so that it is also difficult to implement. The tendency of the rotational speed of the other roller to be properly controlled when the rotational force caused by the rotation of the roller is imparted to the other roller. Therefore, by using the first roller that imparts a relatively large rotational force as the roller positioned vertically downward, the rotational speed of the nip roller can be easily and accurately controlled. When a relatively large rotational force is applied to the first roller, a first driving source for applying a rotational force to the first roller is a second driving source for applying a rotational force to the second roller. Due to the tendency to increase in size, it is preferable to use a roller whose driving source is located on the lower side in the vertical direction as the first roller in terms of maintenance or arrangement of the nip rollers. Furthermore, the first driving source and the second driving source may be respectively provided in the roller, or may be provided in contact with the roller outside the roller.

Hereinafter, an example of the film transfer method of the present invention and the transfer device used in the transfer method will be described in detail with reference to FIGS. 1 to 3. FIG. 1 is a cross-sectional view schematically showing an example of a film transfer device of the present invention. Fig. 2 is a perspective view of a portion of the nip roller 7 in the conveying device A shown in Fig. 1, and Fig. 3 is a sectional view taken along the line X-X in Fig. 2.

FIG. 1 shows a state where the long film 1 is continuously conveyed along the conveying path of the conveying device A. The conveying device A shown in FIG. 1 includes a feeding device 5 for continuously feeding a film by its rotation, a guide roller 6 for supporting a moving film, and a first roller 71 and a second roller facing each other.管 72 的 夹 滚 7。 72 of the folder roller 7. Although it is not shown in the drawing, at the downstream end of the conveying route, a winding device for winding the film is usually provided, and all of the films passing through the conveying route have been sequentially wound into film rolls. In FIG. 1, the solid-line arrows indicate the conveyance direction of the film or the rotation direction of the delivery device.

The transfer of the film in the transfer apparatus A can be performed as follows, for example. First, the long film 1 is continuously transported through a transport route. The long film 1 is usually prepared as a roll of film. After the film roll is assembled in a feeding device (feeding device 5 or another feeding device), while the film 1 is continuously fed from the feeding device, it is continuously transferred in the direction of the solid arrow in FIG. 1.

The first roller 71 constituting the nip roller 7 is configured to be provided with a rotational force by a first drive source (not shown), and the second roller 72 is provided by a second drive source (not shown). By means of rotational force. The first driving source and the second driving source are configured to be electrically connected to the control device 8, and the control device 8 controls the rotational force applied to the first roller 71 and the second roller 72.

As shown in FIG. 3, the first roller 71 and the second roller 72 constituting the nip roller 7 include the conveying areas 71b and 72b in contact with the film to be conveyed, and a wide direction on the outer peripheral surface of the roller. The both end sides are not in contact with the film to be transported, but are in contact areas 71a, 72a in which the outer peripheral surfaces directly contact each other. Since the contact areas 71 a and 72 a are provided, the rotational force from the rotation of the first roller 71 can be efficiently transmitted to the second roller 72.

The surface materials of the first roller 71 and the second roller 72 are not limited, and examples thereof include metal and rubber. The surface materials of the first roller 71 and the second roller 72 may be the same material or different materials.

When the surface material of the first roller 71 or the second roller 72 is rubber, examples of the rubber include: neoprene (CR), silicone rubber (SR), natural rubber (NR), and styrene butadiene rubber. (SBR), nitrile rubber (NBR), ethylene propylene rubber (EPDM), fluorine-containing rubber (FPM), butyl rubber (IIR), polyurethane rubber (U), chlorosulfonated polyethylene (CSM), etc. The surface hardness of the rubber roller is preferably 20 to 95 degrees, and more preferably 7 to 90 degrees.

When the first roller 71 or the second roller 72 is a metal roller, as the base material of the metal roller, various conventional materials can be used, but SUS (stainless steel) 304 is preferred, and surface application is more preferred. Chrome processor.

The diameters of the first roller 71 and the second roller 72 may be the same as or different from each other, for example, 10 mm to 800 mm, and preferably 30 mm to 500 mm. The width of the first roller 71 and the second roller 72 is not limited, but if the center of the width direction of the film to be transported is set to be the same as the width of the first roller 71 and the second roller 72 When the centers are the same, the length from the end of the film to the ends of the first roller 71 and the second roller 72 is preferably 50 to 800 mm, and more preferably 100 mm to 600 mm. The width of the first roller 71 and the second roller 72 is, for example, 400 mm to 2500 mm, and preferably 600 mm to 2000 mm.

In the film conveying device, the film conveying speed when the film is continuously conveyed is, for example, in a range of 2 to 120 m / min, and preferably in a range of 10 to 50 m / min.

The film conveying device may include two or more conveying nip rolls. When two or more transfer nip rollers are included, as long as at least one transfer nip roller is a nip that applies rotational force to the first roller by the first drive source and rotational force to the second roller by the second drive source Just roll. The rest can be made up of, for example, a pinch roller formed by a driving roller that rotates by applying a rotational force to a driving source, and a moving roller that operates in accordance with the rotation of the driving roller. In addition, all the nip rollers for conveyance may be such that the rotational force is applied to the first roller by the first driving source and the rotational force is applied to the second roller by the second driving source as described above. Nip roller.

<Film for transport>

The film transfer device of the present invention is a transfer device suitable for use as an optical film or a raw material film requiring a high-quality film. The raw material film referred to herein includes: a raw material film for manufacturing an optical film, and all intermediate films processed by a raw material film for manufacturing an optical film.

As for the optical film, it can be: polarizing film; protective film; retardation film; the surface of the substrate is coated with a liquid crystal compound and an oriented optical compensation film; penetrates a certain type of polarized light and reflects the polarized light showing the opposite property Reflective polarizing film; film with anti-glare function on the surface with uneven shape; film with anti-reflection function on the surface; reflective film with reflective function on the surface; semi-transparent reflective film with both reflective and penetrating functions; Viewing angle compensation film, etc.

As for the polarizing film, there can be mentioned those who adsorb and orientate iodine on a polyvinyl alcohol resin. The raw material film of this polarizing film is a polyvinyl alcohol resin film. When the polyvinyl alcohol resin with a high water content carried in the manufacturing process of the polarizing film passes through a pair of rollers, if a deviation in rotation speed occurs between the pair of rollers, the roller on the other side easily slips off. So that the film surface is prone to scratch defects. By carrying out the transfer of the polyvinyl alcohol-based resin film by using the film transfer method of the present invention, the occurrence of such defects can be controlled.

As for the protective film, there may be mentioned: a light-transmitting (preferably optically transparent) thermoplastic resin, such as, for example, a chain polyolefin resin (a polypropylene resin, etc.), a cyclic polyolefin resin (a Borneene resins) and other polyolefin resins; such as cellulose ester resins of triethyl cellulose and diethyl cellulose; polyester resins; polycarbonate resins; (meth) acrylic resins ; Polystyrene resin; or a film made of such mixtures and copolymers.

Examples of commercially available products corresponding to retardation films made of cyclic polyolefin resins include "ARTON Film" (made by JSR Corporation), "ESUSHINA (made by Sekisui Chemical Industry Co., Ltd.)", "ZEONOR Film" (manufactured by Japan Zeon Corporation), etc.

For commercially available products corresponding to optical compensation films, there are: "WV Film" (manufactured by FUJI Film Co., Ltd.), "NH Film" (manufactured by Nippon Oil Co., Ltd.), and "NR Film" (New Japan Petroleum Corporation)).

As for the commercially available products corresponding to the reflective polarizing film, for example: "DBEF" (made by 3M company, available from Sumitomo 3M Co., Ltd.), "APF" (made by 3M company, available from Sumitomo 3M Co., Ltd. ).

As for the viewing angle compensation film, an optical compensation film coated with a liquid crystal compound on the surface of the substrate and oriented, a retardation film composed of a polycarbonate resin, and a cyclic polyolefin resin may be mentioned. Retardation film.

The optical film may be a single-layer optical film composed of only any one of the optical films described above, or a laminated optical film composed of a multilayer structure of two, three, or more layers. When the laminated optical film is passed between a pair of rollers, if the rotation speed between the pair of rollers is deviated, a deviation is easily generated between the laminated films. When the conveying device of the present invention is used, it is possible to suppress the occurrence of shift between the laminated films.

As a laminated optical film, a protective film is bonded to a polarizing film via a water-based adhesive agent, for example. In particular, the offset between the laminated films is such that different protective films (e.g., a triethyl cellulose (TAC) film and a cyclic polyolefin resin) are bonded on both sides of the polarizing film with an aqueous adhesive. (COP) film). The present invention is very suitable for an optical film that is prone to such defects.

In addition, even when a plurality of films are laminated as an laminated optical film with an adhesive or an adhesive interposed therebetween, the optical film transport method of the present invention can be suitably applied.

[Manufacturing method of processing film]

The method for producing a treatment film of the present invention includes a treatment step of applying a treatment to a raw material film to obtain a treatment film, and a transfer step of continuously transferring the raw material film or the treatment film by the above-mentioned film transportation method. The raw material film referred to herein includes any film before the completion of the processing performed in the processing step, and the term "processed film" refers to the film after the processing in the processing step.

In the processing step of the manufacturing method of the present invention, the processing to obtain an optical film is performed, and the processed film is an optical film. In the processing step of the manufacturing method of the present invention, the process of obtaining an intermediate film of an optical film is performed, and the processed film is an intermediate film. The optical film is as described above.

As described above, the method for manufacturing a treatment film of the present invention has a nip roller conveyance using a nip roller that applies a rotational force to a first roller via a first drive source and a rotational force to a second roller via a second drive source. Steps, so that the deviation of the rotation speed between the rollers of one of the nip rollers can be reduced. In addition, it is possible to reduce the occurrence of defects such as scratches on the film surface caused by variations in the rotation speed of the nip roller.

The manufacturing apparatus of the processing film of this invention is equipped with the processing part which applies a process to a raw film, and produces a processing film, and the conveying part which continuously transfers a raw film or a processing film by the said film conveying apparatus. Hereinafter, with reference to FIG. 4, an example of the manufacturing apparatus of the processing film of this invention, and the manufacturing method of the processing film using this apparatus are demonstrated in detail.

<Manufacturing Device for Polarizing Film>

Fig. 4 is a cross-sectional view schematically showing an example of an apparatus for producing a treatment film of the present invention. Specifically, the manufacturing apparatus of the processing film shown in FIG. 4 is a manufacturing apparatus of a polarizing film. That is, in the manufacturing apparatus of the processing film shown in FIG. 4, the processing film is a polarizing film, and the processing section is subjected to a process for producing a polarizing film from a polyvinyl alcohol-based resin film.

The manufacturing apparatus of the polarizing film shown in FIG. 4 is configured such that a raw material film 10 (unstretched) made of a polyvinyl alcohol-based resin is continuously rolled out from the raw material roll 11 while being supplied along the film conveying route. Transported in this order: the swelling bath (swelling solution contained in the swelling tank) provided on the film transport route 13, the dyeing bath (staining solution contained in the dyeing tank) 15, the first cross-linking bath (cross-linking) The first cross-linking liquid contained in the tank) 17a, the second cross-linking bath (the second cross-linking liquid contained in the cross-linking tank) 17b, and the cleaning bath (the cleaning liquid contained in the wash tank) 19, and finally Pass it through the drying furnace 21. The obtained polarizing film 23 is, for example, directly transported to the next polarizing plate manufacturing step (the step of laminating the protective film on one or both sides of the polarizing film 23).

In the following description, the "treatment tank" is a general term including a swelling tank, a dyeing tank, a cross-linking tank, and a cleaning tank, and the "treatment liquid" is a general term including a swelling liquid, a dyeing liquid, a cross-linking liquid, and a cleaning liquid. "Processing bath" is a generic term that includes a swelling bath, a dyeing bath, a crosslinking bath, and a cleaning bath. When considering the manufacturing apparatus of the processing film of the present invention, the processing unit is composed of a swelling bath, a dyeing bath, a crosslinking bath, a cleaning bath, and a drying furnace. In addition, the polarizing film 23, which is a film itself after the processing in the processing section of the manufacturing apparatus of the polarizing film is completed and passed through the drying furnace, is equivalent to the processing film, and the films in the other processes are equivalent to the raw film.

The polarizing film can be continuously manufactured into long polarizing films in the following manner: while the long raw material film is rolled out from the raw material roll, it is continuously conveyed along the film conveying path of the polarizing film manufacturing device, and is being implemented. It is immersed in the processing liquid accommodated in the processing tank, and then pulled out to bring it into contact with the predetermined processing liquid. The processing liquid contact step is followed by a drying step. Here, in the treatment liquid contacting step, as long as the film can be brought into contact with the treatment liquid to perform the treatment, the method is not limited to a method of immersing the film in a treatment bath, and may be treatment by spraying, flowing down, dripping, or the like. A method in which a liquid adheres to the surface of a film to treat the film. In the case where the treatment liquid contacting step is performed by immersing the film in a treatment bath, the treatment bath that performs one treatment liquid contacting step is not limited to one, and may be dipped in two or more treatment baths in sequence. To perform a process liquid contacting step.

In addition to the processing bath described above, the film transfer route of the polarizing film manufacturing device can also be constructed by arranging the following components in place: the guide rollers 30 to 48 that support the film being transferred, or can further change the film transfer direction , 60, 61; and the nip rollers 50 to 55 that press and hold the conveyed film and can give the film conveying force by rotating it, or can further change the film conveying direction.

The guide rollers and nip rollers can be arranged before or after each treatment bath, so that the film in the treatment bath can be introduced, impregnated, and pulled out from the treatment bath (see FIG. 4). For example, by providing one or more guide rollers in each processing bath and carrying the film along these guide rollers, the film can be immersed in each processing bath.

At least one of the nip rollers 50, 51, 52, 53a, 53b, 54, and 55 is provided with a rotational force from the first driving source to the first roller as described in the film conveying device described above, and the second driving source pair A pinch roller that imparts a rotational force to the second roller. The higher the moisture content of the film, the more likely it is that defects such as scratches on the film surface occur due to deviations in the rotation speed between a pair of rollers. Therefore, from the viewpoint of reducing the occurrence of scratches on the film surface, it is preferable that the nip rollers 51, 52, 53a, 53b, and 54 that the film passes from the immersion in the swelling tank 13 to the introduction of the drying device 21 are As described in the film conveying device, a pinch roller that imparts a rotational force from a first drive source to a first roller and a rotational force from a second drive source to a second roller. In addition, since the surface of the film has become fragile after the cross-linking treatment is applied, the defect that the surface of the film is scratched easily occurs. Therefore, from the viewpoint of reducing the occurrence of scratches on the film surface, it is preferable that the nip rollers 53a, 53b, and 54 are the first rollers to the first roller as described in the film conveying device described above. A pinch roller that imparts a rotational force and a rotational force to a second roller from a second drive source.

The polarizing film manufacturing apparatus shown in FIG. 4 is provided with nip rollers (nip rollers 50 to 54) before and after each processing bath, so that it can be implemented in any one or more processing baths. A circumferential speed difference is applied between the arranged nip rollers to perform longitudinal uniaxial stretching between the rollers. Each step will be described below.

(Swelling step)

The swelling step is performed for the purpose of removing foreign matter on the surface of the raw material film 10, removing plasticizer in the raw material film 10, imparting easy dyeability, plasticizing the raw material film 10, and the like. The processing conditions are determined within a range in which the object can be achieved without causing defects such as extreme dissolution or devitrification of the raw material film 10.

Referring to FIG. 4, the swelling step can be carried out along the film transport route while continuously rolling out the raw material film from the raw material roll 11, and immersing the raw material film 10 in the swelling bath 13 for a predetermined time, and then Pull out and implement. In the example of FIG. 4, from the time when the raw material film 10 is taken up to the immersion in the swelling bath 13, the raw material film 10 is conveyed along the film conveyance path constructed by the guide rollers 60 and 61 and the nip roller 50. During the swelling process, the film is conveyed along the film conveyance path constructed by the guide rollers 30 to 32 and the nip roller 51.

As for the swelling liquid of the swelling bath 13, in addition to pure water, boric acid (Japanese Patent Application Laid-Open No. 10-153709) and chloride (Japanese Patent Application Laid-Open No. 06-153709) added in a range of about 0.01 to 10% by weight may be used. 281816), aqueous solutions of inorganic acids, inorganic salts, water-soluble organic solvents, alcohols, etc.

The temperature of the swelling bath 13 is, for example, about 10 to 50 ° C, preferably about 10 to 40 ° C, and more preferably about 15 to 30 ° C. The immersion time of the raw material film 10 is preferably about 10 to 300 seconds, and more preferably about 20 to 200 seconds. When the raw material film 10 is a polyvinyl alcohol-based resin film stretched in a gas in advance, the temperature of the swelling bath 13 is, for example, about 20 to 70 ° C, preferably about 30 to 60 ° C. The immersion time of the raw material film 10 is preferably about 30 to 300 seconds, and more preferably about 60 to 250 seconds.

In the swelling process, the problem that the raw film 10 swells in the width direction and causes the film to wrinkle easily occurs. As a method for removing the wrinkle and conveying the film, the rolls can be exemplified in the guide rollers 30, 31, and / or 32, such as spreading rollers, spiral rollers, and crown rollers, or using Such as cloth guide device, bending stick, tenter clip and other expansion device. Another method to suppress wrinkling is to apply a stretching treatment. For example, a uniaxial stretching process can be performed in the swelling bath 13 using the difference in the peripheral speed of the nip roll 50 and the nip roll 51.

In the swelling process, since the film also swells and expands in the film conveying direction, when the film is not actively stretched, in order to eliminate the slack of the film in the conveying direction, it is preferable to take a clamp disposed before and after the swelling bath 13, for example. The speed of the rollers 50 and 51 is controlled. In addition, in order to stabilize the film transfer in the swelling bath 13, use a water shower to control the water flow in the swelling bath 13, or use an EPC (Edge Position Control) device (a device that detects the end of the film to prevent the film from bending) Etc. are also useful.

In the example shown in FIG. 4, the film drawn from the swelling bath 13 passes through the guide roller 32, the nip roller 51, and the guide roller 33 in this order and is introduced into the dyeing bath 15.

(Dyeing step)

The dyeing step is performed for the purpose of causing the polyvinyl alcohol-based resin film after the swelling treatment to adsorb and orient the dichroic dye. The processing conditions are determined within a range in which the purpose can be achieved without causing defects such as excessive dissolution or devitrification of the membrane. Referring to FIG. 4, the dyeing step can be carried out by following the film conveying route composed of the nip roller 51, the guide rollers 33 to 36 and the nip roller 52, and making the swelled film a predetermined time. It was immersed in the dyeing bath 15 (the processing liquid contained in the dyeing tank) and then pulled out. In order to improve the dyeability of the dichroic pigment, the film supplied to the dyeing step is preferably a film to which at least a certain degree of uniaxial stretching treatment is applied, or is preferably a film without uniaxial stretching treatment before the dyeing treatment. Instead, a uniaxial stretching process is performed during the dyeing process, or in addition to the uniaxial stretching process before the dyeing process.

When iodine is used as a dichroic pigment, the dyeing liquid in the dyeing bath 15 can be, for example, an aqueous solution having a concentration in a weight ratio of iodine / potassium iodide / water = about 0.003 to 0.3 / about 0.1 to 10/100. Other iodides such as zinc iodide can be used, or potassium iodide can be used in combination with other iodides. In addition, compounds other than iodide, such as boric acid, zinc chloride, and cobalt chloride, may be coexisted. When boric acid is added, it is different from the crosslinking treatment described below because it contains iodine. As long as it is 100 parts by weight of water and the aqueous solution contains about 0.003 parts by weight or more of iodine, it can be regarded as a dyeing bath 15. The temperature of the dyeing bath 15 when the film is immersed is generally about 10 to 45 ° C, preferably 10 to 40 ° C, more preferably 20 to 35 ° C, and the immersion time of the film is generally about 30 to 600 seconds, preferably 60 to 300 seconds.

When a water-soluble dichroic dye is used as a dichroic dye, the dyeing liquid system of the dyeing bath 15 can use, for example, an aqueous solution having a concentration of dichroic dye / water = about 0.001 to 0.1 / 100 in a weight ratio. In this dyeing bath 15, dyeing and finishing auxiliaries can be coexisted, and for example, inorganic salts such as sodium sulfate and surfactants can be contained. A dichroic dye may be used individually by 1 type, and may use 2 or more types of dichroic dyes together. The temperature of the dyeing bath 15 when the film is immersed is, for example, about 20 to 80 ° C, preferably 30 to 70 ° C, and the immersion time of the film is generally about 30 to 600 seconds, preferably about 60 to 300 seconds.

As described above, during the dyeing step, the film can be uniaxially stretched in the dyeing bath 15. The uniaxial stretching of the film can be performed by a method such as applying a peripheral speed difference between the nip roll 51 and the nip roll 52 disposed before and after the dyeing bath 15.

In the dyeing process, it is also the same as the swelling process. In order to remove the wrinkles of the film and transport the polyvinyl alcohol resin film, the guide rollers 33, 34, 35, and / or 36 can be used such as spreading rollers, spiral rollers, Crown rollers have rollers with expansion function, or other expansion devices such as cloth guides, bending sticks, and tenter clips. Another method for suppressing wrinkling is the same as the swelling treatment, in which a stretching treatment is applied.

In the example shown in FIG. 4, the film drawn from the dyeing bath 15 passes through the guide roller 36, the nip roller 52, and the guide roller 37 in this order and is introduced into the first crosslinking bath 17a.

(Crosslinking step)

The cross-linking step is performed for the purpose of water resistance or hue adjustment (to prevent the film from being cyanized, etc.) caused by cross-linking. In the example shown in FIG. 4, two cross-linking baths are arranged as the cross-linking bath for performing the cross-linking step, and the first cross-linking step performed for the purpose of water resistance is performed in the first cross-linking bath 17 a. The second cross-linking step performed for the purpose of hue adjustment is performed in the second cross-linking bath 17b. Referring to FIG. 4, the first cross-linking step can be performed by transporting along a film transport path constructed by the nip roller 52, the guide rollers 37 to 40, and the nip roller 53 a, and the first cross-linking In the bath 17a (the first cross-linking liquid contained in the cross-linking tank), the film after the dyeing treatment was immersed for a predetermined time, and then pulled out. The second cross-linking step can be carried out by following the film transport route constructed by the nip roller 53a, the guide rollers 41 to 44 and the nip roller 53b, and the second cross-linking bath 17b (cross-linking) In the second cross-linking liquid contained in the tank, the film after the first cross-linking step is immersed for a predetermined time, and then pulled out. Hereinafter, when the cross-linking bath is referred to, both the first cross-linking bath 17a and the second cross-linking bath 17b are included. When the cross-linking liquid is referred to, the first cross-linking liquid and the second cross-linking liquid are included.

As the crosslinking solution, a solution in which a crosslinking agent is dissolved in a solvent can be used. Examples of the crosslinking agent include boron compounds such as boric acid and borax, and glyoxal and glutaraldehyde. These may be one type, or two or more types may be used in combination. As the solvent, for example, water may be used, but it may further contain an organic solvent having compatibility with water. The concentration of the crosslinking agent in the crosslinking solution is not limited, but is preferably in the range of 1 to 20% by weight, and more preferably 6 to 15% by weight.

The crosslinking solution may be a solution containing boric acid, for example, about 1 to 10 parts by weight with respect to 100 parts by weight of water. When the dichroic pigment used in the dyeing process is iodine, it is preferable that the crosslinking solution contains iodide in addition to boric acid, and its amount can be set to 1 to 30 parts by weight with respect to 100 parts by weight of water. Examples of the iodide include potassium iodide and zinc iodide. In addition, compounds other than iodide, for example, zinc chloride, cobalt chloride, zirconium chloride, sodium thiosulfate, potassium sulfite, sodium sulfide, and the like may coexist.

During the cross-linking treatment, the concentrations of boric acid and iodide, and the temperature of the cross-linking bath may be appropriately changed according to the purpose. For example, when the purpose of the cross-linking treatment is the first cross-linking solution that is water-resistant by cross-linking. It can be an aqueous solution having a concentration in terms of weight ratio of boric acid / iodide / water = 3 to 10/1 to 20/100. If necessary, other cross-linking agents may be used instead of boric acid, and boric acid and other cross-linking agents may also be used in combination. The temperature of the first crosslinking bath 17a when the film is dipped is generally about 50 to 70 ° C, preferably 53 to 65 ° C, and the immersion time of the film is generally about 10 to 600 seconds, preferably 20 to 300 seconds, More preferably, it is 20 to 200 seconds. In addition, if the stretched polyvinyl alcohol-based resin film is sequentially dyed and subjected to the first crosslinking treatment before the swelling treatment, the temperature of the first crosslinking bath 17a is generally about 50 to 85 ° C, preferably 55 to 80 ° C.

For the second cross-linking liquid for the purpose of adjusting hue, for example, when using iodine as a dichroic dye, the concentration can be used in a weight ratio of boric acid / iodide / water = 1 to 5/3 to 30/100. The temperature of the second crosslinking bath 17b when the film is impregnated is generally about 10 to 45 ° C, and the impregnation time of the film is generally about 1 to 300 seconds, preferably 2 to 100 seconds.

The cross-linking treatment may be performed a plurality of times, and is generally performed 2 to 5 times. In this case, the composition and temperature of each of the crosslinking baths used may be the same or different if they are within the above-mentioned ranges. Each of the cross-linking treatment for water resistance due to cross-linking and the cross-linking treatment for adjusting hue can be performed in a plurality of steps.

A uniaxial stretching process may be performed in the 1st crosslinking bath 17a using the peripheral speed difference of the nip roll 52 and the nip roll 53a. Alternatively, the second cross-linking bath 17b may be subjected to a uniaxial stretching treatment by utilizing the difference in the peripheral speed between the nip rollers 53a and 53b.

In the cross-linking process, the same as the swelling process, the polyvinyl alcohol-based resin film is transported while removing the wrinkles of the film. Therefore, the guide rollers 38 to 44 can be used such as spreading rollers, spiral rollers, and crown rollers. Functional rollers, or other expansion devices such as cloth guides, bending sticks, and tenter clips. Another method for suppressing wrinkling is the same as the swelling treatment, in which a stretching treatment is applied.

In the example shown in FIG. 4, the film drawn from the second crosslinking bath 17b passes through the guide roller 44 and the nip roller 53b in this order and is introduced into the cleaning bath.

(Cleaning step)

The example shown in FIG. 4 includes a cleaning step after the crosslinking step. The cleaning treatment is carried out for the purpose of removing excess boric acid or iodine and other agents adhered to the polyvinyl alcohol resin film. The washing step is performed, for example, by immersing the cross-linked polyvinyl alcohol-based resin film in the washing bath 19. In addition, the cleaning step may be performed by spraying the cleaning solution into the shower to replace the step of immersing the film in the cleaning bath 19, or by using the immersion in the cleaning bath 19 and spraying the cleaning solution together.

FIG. 4 shows an example of a case where a polyvinyl alcohol-based resin film is immersed in a cleaning bath 19 to perform a cleaning treatment. The temperature of the cleaning bath 19 for the cleaning treatment is generally about 2 to 7 ° C, and the immersion time of the film is generally about 2 to 120 seconds.

Furthermore, in the cleaning process, for the purpose of conveying the polyvinyl alcohol-based resin film while removing the wrinkles, the guide rollers 45, 46, 47, and / or 48 can be used such as spreading rollers, spiral rollers, and crown rollers. Roller with expansion function, or use other expansion devices such as cloth guide device, bending stick, tenter clip. In addition, in the film cleaning treatment, a stretching treatment may be applied in order to suppress wrinkling.

(Stretching step)

As described above, the raw material film 10 is between the above-mentioned series of processing liquid contacting steps (that is, before or after any one or more processing liquid contacting steps and / or any one or more processing liquid contacting steps), in a wet manner or Uniaxial stretching is performed dry. A specific method of the uniaxial stretching process is, for example, applying a peripheral speed difference between two nip rollers (for example, two nip rollers arranged before and after the treatment bath) constituting the film conveying path to perform longitudinal uniaxial stretching between rollers. The stretching is, for example, heating roll stretching or tenter stretching described in Japanese Patent No. 2731813, and stretching between rolls is preferred. The uniaxial stretching step may be performed a plurality of times between rolling out the raw material film 10 from the raw material roll 11 to obtaining the polarizing film 23. As mentioned above, the stretching treatment is also beneficial for controlling the wrinkling of the film.

Based on the raw material film 10 immediately after being unwound from the raw material roll, the final cumulative stretching ratio of the polarizing film 23 is generally about 4.6 to 7 times, preferably 5 to 6.5 times. The stretching step may be performed in any treatment liquid contact step. When the stretching treatment is performed in two or more treatment liquid contact steps, the stretching treatment may also be performed in any treatment liquid contact step.

(Polarizing film)

In the present invention, the polarizing film is a uniaxially stretched polyvinyl alcohol-based resin film that adsorbs and orients a dichroic pigment (iodine or dichroic dye). The polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based resin film is generally produced by saponifying a polyvinyl acetate-based resin. The saponification degree is generally about 85 mol% or more, preferably about 90 mol% or more, and more preferably about 99 mol% or more. The polyvinyl acetate-based resin is, for example, a copolymer of vinyl acetate and other monomers copolymerizable therewith, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate. Examples of other copolymerizable monomers include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids. The polymerization degree of the polyvinyl alcohol-based resin is generally about 1,000 to 10,000, preferably about 1500 to 5,000.

These polyvinyl alcohol-based resins may be modified, for example, polyvinyl formaldehyde, polyvinyl acetal, polyvinyl butyral, etc. modified by aldehydes may also be used.

In the present invention, as a starting material (raw material film 10) for manufacturing a polarizing film, a thickness of 65 μm or less (for example, 60 μm or less), preferably 50 μm or less, more preferably 35 μm or less, and still more preferably 30 μm or less Stretched polyvinyl alcohol resin film (raw material film 10). Thereby, a polarizing film of a film with increasing market demand can be obtained. The width of the starting material (raw material film 10) is not particularly limited, and may be, for example, about 70 to 6000 mm. The starting material (raw material film 10) is, for example, a roll (raw material roll) of an unstretched polyvinyl alcohol-based resin film prepared as a long strip as described above.

In addition, the polyvinyl alcohol-based resin film used in the present invention may be a substrate film laminated to support the film, that is, the polyvinyl alcohol-based resin film may also be prepared into a substrate film and a substrate film. Laminated film made of polyvinyl alcohol resin film laminated on top. In this case, the polyvinyl alcohol-based resin film can be produced, for example, by coating a coating solution containing a polyvinyl alcohol-based resin on at least one side of the base film and then drying it.

As the base film, for example, a film made of a thermoplastic resin can be used. A specific example thereof is a film made of a thermoplastic resin having translucency, preferably an optically transparent thermoplastic resin, and may be, for example, a chain polyolefin resin (such as a polypropylene resin) or a cyclic polyolefin resin. Polyolefin resins of resins (norbornene-based resins, etc.); cellulose resins such as triethyl cellulose and diethyl cellulose; such as polyethylene terephthalate, polyterephthalic acid Polyester resins of succinate; polycarbonate resins; (meth) acrylic resins such as methyl methacrylate resins; polystyrene resins; polyvinyl chloride resins; acrylonitrile / butadiene / Styrene resin; acrylonitrile / styrene resin; polyvinyl acetate resin; polyvinylidene chloride resin; polyamide resin; polyacetal resin; modified polyphenylene ether resin Polyfluorene-based resins; Polyether fluorene-based resins; Polyarylate resins; Polyamidamine-imide-based resins; Polyfluorene-imide-based resins, and the like.

    [Example]    

Hereinafter, the present invention will be described more specifically with examples, but the present invention is not limited by these examples.

<Example 1>

The film is transferred using the film transfer device shown in FIG. 1. As a film to be transported, a polyvinyl alcohol-based resin film is used. The first roller 71 and the second roller 72 are rollers each having a diameter of 300 mm, a width of 2000 mm, and a surface material of NBR. The rotational force (T1) applied from the first driving source to the first roller 71 is set to a fixed 51.5 N / m, and the rotational force (T2) applied from the second driving source to the second roller 72 is set. The ratio P (= (T2 / T1) × 100) to T1 varies within the range of 0 to 4.5%, and the first roll is measured using a measuring device (contact digital palm-type tachometer, manufactured by Ono Sokoku Corporation). Rotation speed of the drum 71 and the second roller 72. Furthermore, on the downstream side of the nip roller 7, the film tension was adjusted so that the film tension could be 570N.

FIG. 5 is a graph plotting the measurement results of the rotation speed (V1) of the first roller 71 and the measurement results of the rotation speed (V2) of the second roller 72 in Example 1. FIG. In FIG. 5, the values of the rotational force (T1) applied to the first roller 71 are combined and shown. When P is 0%, the rotation speed (V1) of the first roller 71 is 30.074 m / min, and the rotation speed (V2) of the second roller 72 is 29.974 m / min. When P is 4.5% (when T2 is 2.32 N · m), the rotation speed (V1) of the first roller 71 is 30.052 m / min, and the rotation speed (V2) of the second roller 72 is 30.046 m / min. , And the rotation speed difference ratio R ([(V1-V2) / V1] × 100) is 0.02%.

As can be seen from FIG. 5, in Example 1, the rotational speed difference ratio R can be controlled to 0.2% or less by applying a rotational force of 4.5% of T1 to the second roller 72 from the second driving source.

<Example 2>

The film is transferred using the film transfer device shown in FIG. 1. As a film to be transported, a polyvinyl alcohol-based resin film is used. As the first roller 71 and the second roller 72, rollers having a diameter of 420 mm, a width of 2100 mm, and a surface material of NBR were used. While using a measuring device (rotary encoder) to measure the rotation speed (V1) of the first roller, the rotation speed (V1) of the first roller 71 was 22.928 m / min from the first driving source to the first The roller 71 imparts a rotational force (T1), and at the same time, the ratio P (= (T2 / T1) × 100) of the rotational force (T2) to T1 given by the second drive source to the second roller 72 is 0. The rotation speed of the second roller 72 was measured within a range of 60%. The tension of the film was adjusted on the downstream side of the nip roller 7 so that the tension of the film became 1000 N.

Fig. 6 is a graph plotting the measurement results of the rotation speed (V1) of the first roller 71 and the measurement results of the rotation speed (V2) of the second roller 72 in Example 2. In FIG. 6, the rotational force (T1) of the first roller 71 and the rotational force (T2) of the second roller 72 are combined. Table 1 shows the values of V1, V2, T1, and T2 in Example 2. From these results, it can be seen that when P is 60% (when T2 is 144 N · m), the rotation speed difference ratio R ([(V1-V2) / V1] × 100) is 0.19%.

As can be seen from FIG. 6 and Table 1, in Example 2, by applying a rotational force of 60% of T1 to the second roller 72 from the second driving source, the rotational speed difference ratio R can be controlled to be 0.2% or less.

Claims (10)

    A film conveying method includes a nip roller conveying step for conveying a film by rotation of a nip roller including a first roller and a second roller facing each other, the nip roller conveying step including In the first roller rotation step in which the first roller imparts a rotational force to rotate the first roller, and the second roller rotation step in which the second roller is rotated, in the second roller rotation step, from the second driving source A rotational force is applied to the second roller.         The method for conveying a film according to item 1 of the scope of patent application, wherein in the second roller rotation step, the second roller rotates with the rotation of the first roller and is further imparted with rotation from the second driving source. force.         The method for conveying the film according to item 1 or item 2 of the scope of patent application, wherein the rotation force imparted to the second roller from the second driving source in the second roller rotation step is smaller than that in the first roller. In the rotating step, a rotating force is applied to the first roller from the first driving source.         The method for transporting the film according to any one of claims 1 to 3, wherein the film is an optical film or a raw film thereof.         A film conveying device includes a first roller and a second roller that face each other, and a nip roller that conveys the film by rotation, a first driving source that imparts a rotational force to the first roller, and A second driving source that imparts a rotational force to the second roller.         The film transfer device according to item 5 of the patent application scope, wherein the film-based optical film or a raw film thereof is used.         A method for manufacturing a treatment film, comprising: a treatment step of applying a treatment to a raw material film to obtain a treatment film; and a method for conveying a film according to any one of claims 1 to 3 in a patent application scope The conveyance process of the said raw material film or the said processing film.         The method for manufacturing a treatment film according to item 7 of the scope of patent application, wherein the treatment film is an optical film.         A processing film manufacturing device includes a processing unit that applies processing to a raw film to obtain a processed film, and a transfer device for transferring the aforementioned raw film or the aforementioned processed film by a film transfer device according to item 5 of the patent application scope. Transport Department.         The apparatus for manufacturing a processing film according to item 9 of the scope of application for a patent, wherein the processing film is an optical film.