TW202121071A - Polarizing film manufacturing method, polarizing film manufacturing device, and control system - Google Patents

Abstract

To provide a polarizing film manufacturing method capable of stabilizing the conveyance of a polarizer between a processing tank and laminating rolls even when the moisture percentage of the polarizer on the outlet side of an oven is low. In a method of manufacturing a polarizing film according to the present invention, first tension cut rolls for conveying a polarizer are disposed between a processing tank and laminating rolls, and tension meters are further disposed on the downstream sides of the first tension cut rolls between the processing tank and the laminating rolls, and a control device controls the peripheral speeds of the first tension cut rolls so that a tension measured by the tension meters becomes a predetermined value. In addition, after the control is carried out, the peripheral speed of a first tension cut roll disposed on the outlet side of the processing tank is measured, and the peripheral speeds of second tension cut rolls are controlled so that the ratio of the measured peripheral speed P1c' of the first tension cut roll and the peripheral speed of the second tension cut roll becomes a predetermined value.

Description

Polarizing film manufacturing method, polarizing film manufacturing device and control system

The invention relates to a method of manufacturing a polarizing film, a device and a control system for manufacturing a polarizing film. The method of manufacturing a polarizing film is to dye the original film with a dichroic substance in a processing tank and simultaneously perform uniaxial stretching, and then use the oven to make This is dried to produce a polarizer, and the polarizer and the protective film are bonded with a bonding roller to produce a polarizing film. In particular, the present invention relates to a polarizing film manufacturing method and a polarizing film manufacturing apparatus that can stabilize the transportation of the polarizing material between the processing tank and the bonding roller even if the moisture content of the polarizing material on the delivery side of the oven is low And control system.

In the past, a polarizing film containing a polarizer was used as a constituent material of a liquid crystal display device or polarized sunglasses. The polarizing film is composed of, for example, a polarizing member dyed with a dichroic substance such as iodine and a protective film that is attached to the polarizing member to protect the polarizing member. For example, the polarizing film is manufactured by a roll-to-roll method as described in Patent Document 1. The roll-to-roll method is to obtain a strip-shaped polarizing film from manufacturing a strip-shaped polarizer to a strip-shaped protective film. A series of steps are carried out on a manufacturing line. Prior art literature Patent literature

Patent Document 1: Japanese Patent Laid-Open No. 2004-341515

The problem to be solved by the invention Fig. 3 is a diagram schematically showing a schematic configuration example of a manufacturing device and a control system used in a conventional manufacturing method of a polarizing film of a roll-to-roll system. The arrows shown in solid lines in FIG. 3 indicate the conveying direction of each film. As shown in Figure 3, in the conventional polarizing film manufacturing method, the original film F0 wound on the release roll 1 is first released and immersed in the treatment tank 2 (for example, from the upstream of the original film F0 in the conveying direction The side is sequentially composed of a swelling treatment tank, a dyeing treatment tank, a cross-linking treatment tank, an extension treatment tank, and a washing treatment tank. In the treatment bath, dyeing with dichroic substances such as iodine or dichroic dyes is performed at the same time Uniaxial extension. Then, it was dried by the oven 3, and the polarizer F1 was obtained. Next, for example, the coater 6 is used to apply an active energy ray hardening type adhesive to both surfaces of the polarizer F1. In addition, for example, an active energy ray-curable adhesive is applied to one side of the protective film F2 discharged from a discharge roller (not shown) with a coater (not shown). Then, the protective film F2 coated with the adhesive is bonded to both sides of the polarizer F1 coated with the adhesive by the bonding roller 7. After that, although not shown, the adhesive between the polarizer F1 and the protective film F2 is irradiated with active energy rays from the active energy ray irradiation device to harden it, then dried in an oven, and other films (surface Protective film, etc.), thereby manufacturing a polarizing film.

As shown in FIG. 3, the conventional manufacturing apparatus includes a first tension segment roller 20 and a second tension segment roller 60. The first tension segment roller 20 is arranged between the processing tank 2 and the laminating roller 7 and used To transport the polarizer F1 (including the original film F0 after processing in the processing tank 2 and before drying in the oven 3), the second tension segment roller 60 is used to transport the original film F0 in the processing tank 2. In the example shown in FIG. 3, three sets of first tension segment rollers 20a to 20c are arranged as the first tension segment rollers 20, and five sets of second tension segment rollers 60a to 60e are arranged as the second tension segments. Section roller 60. In the example shown in FIG. 3, the first tension segment roller 20 and the second tension segment roller 60 are both nip rollers.

The conventional control system 100A includes a control device 40 and an encoder 50. The encoder 50 measures the number of rotations of the bonding roller 7 and outputs it to the control device 40. The control device 40 calculates the circumferential speed P0' of the bonding roller 7 based on the input rotation number of the bonding roller 7 and the outer diameter of the bonding roller 7 stored in advance. Then, the control device 40 controls the peripheral speed of the first tension segment roller 20 so that the ratio of the peripheral speed P0' of the laminating roller 7 to the peripheral speed of the first tension segment roller 20 becomes a predetermined value (fixed Ratio control). Specifically, if the peripheral speed of the first tension segment roller 20a is P1a, the peripheral speed of the first tension segment roller 20b is P1b, and the peripheral speed of the first tension segment roller 20c is P1c, the control device 40 P1a/P0'=α1, P1b/P0'=α2, P1c/P0'=α3 (α1, α2, and α3 are predetermined constants) are used to determine the peripheral speeds P1a, P1b, and P1c, and the first tension is divided The driving parts (motors, etc. not shown) of the segment rollers 20a-20c send out control signals to make the first tension segment rollers 20a-20c rotate at the respective peripheral speeds P1a-P1c. Generally, the laminating roller 7 is rotated at a predetermined fixed peripheral speed, so the first tension segment roller 20 also rotates at a fixed peripheral speed. In addition, although the example shown in FIG. 3 calculates the peripheral speed P0' of the laminating roller 7 based on the result of measuring the number of rotations of the laminating roller 7, and controls the first tension segment roller 20 based on the calculated peripheral speed P0' However, there are cases in which the peripheral speed of the first tension segment roller 20 is controlled based on the peripheral speed setting value or the rotation number setting value of the laminating roller 7, and the peripheral speed of the laminating roller 7 is not actually measured/calculated.

In addition, the control device 40 controls the peripheral speed of the second tension segment roller 60 (fixed) so that the ratio of the peripheral speed P0' of the bonding roller 7 to the peripheral speed of the second tension segment roller 60 becomes a predetermined value. Ratio control). Specifically, if the peripheral speed of the second tension segment roller 60a is P2a, the peripheral speed of the second tension segment roller 60b is P2b, the peripheral speed of the second tension segment roller 60c is P2c, and the peripheral speed of the second tension segment roller 60c is P2c. The peripheral speed of the roller 60d is P2d and the peripheral speed of the second tension segment roller 60e is P2e, the control device 40 sets P2a/P0'=β1, P2b/P0'=β2, P2c/P0'=β3, P2d/P0'=β4, P2e/P0'=β5 (β1, β2, β3, β4, and β5 are predetermined constants) to determine the peripheral speeds P2a, P2b, P2c, P2d, and P2e, and for the second tension segment roller The driving parts of 60a-60e (motors not shown in the figure, etc.) send out control signals to make the second tension segment rollers 60a-60e rotate at the respective peripheral speeds P2a-P2e. As mentioned above, since the bonding roller 7 generally rotates at a fixed peripheral speed, the second tension segment roller 60 also rotates at a fixed peripheral speed. The fixed ratio control of the peripheral speed of the second tension segment roller 60 is required to stretch the original sheet film F0 at a predetermined stretch magnification determined in advance.

In the manufacturing method of the polarizing film using the conventional control system 100A described above, the first tension segment roller 20 that transports the polarizing member F1 between the processing tank 2 and the bonding roller 7 is controlled by a fixed ratio control method The peripheral speed is determined by the ratio α1~α3 to determine the set tension of the transported polarizer F1 at each position. However, the actual tension generated by the polarizer F1 will vary greatly depending on the state of the polarizer F1. If the actual tension of the polarizer F1 changes significantly, problems may occur in the transportation of the polarizer F1. In addition, if excessive tension is generated, the polarizer F1 may break. Moreover, even if the polarizing film is manufactured under the same manufacturing conditions, the reproducibility of the tension actually generated by the polarizer F1 is not good. Therefore, the operator must manually fine-tune the ratios α1~α3. The transportation of the polarizer F1 (transportation between the processing tank 2 and the bonding roller 7) in the conventional polarizing film manufacturing method does not easily cause problems when the polarizer F1 can expand and contract relatively greatly. That is, as long as the polarizer F1 can expand and contract greatly, even if the actual tension changes greatly, the influence of the tension fluctuation can be relieved by the expansion and contraction of the polarizer F1.

However, in recent years, there has been a tendency to produce a polarizer F1 with a low moisture content (for example, the moisture content of the polarizer F1 on the delivery side of the oven 3 is 15% or less). The polarizer F1 with low moisture content hardly stretches, so it is difficult to relieve the influence of tension fluctuations under the conventional manufacturing method of polarizing film, and there are problems in the transportation of the polarizer F1 or the polarizer F1 is broken. High question.

Therefore, the subject of the present invention is to provide a polarizing film manufacturing method and polarizing film that can stabilize the transportation of the polarizer between the processing tank and the bonding roller even if the moisture content of the polarizer on the delivery side of the oven is low. Film manufacturing equipment and control system.

Means to solve the problem In order to solve the aforementioned problems, the present invention provides a method of manufacturing a polarizing film. The manufacturing method is to dye the original film with a dichroic substance in a processing tank and simultaneously perform uniaxial stretching, and then dry it in an oven to produce a polarized film. The polarizing element and the protective film are laminated with a laminating roller to produce a polarizing film; this manufacturing method arranges a first tension segment roller for conveying the polarizing member between the processing tank and the laminating roller, and A tensiometer is arranged between the processing tank and the laminating roller and on the downstream side of the first tension segment roller; and the manufacturing method includes a first control step, and the first control step is such that the tension meter is used to measure The peripheral speed of the first tension segment roller is controlled in such a way that the tension becomes a predetermined value.

The "tension segment roller" in the present invention (the first tension segment roller and the second tension segment roller in the ideal method described later) means that the film will not slip on the roller and the upstream and downstream of the roller can be controlled For rollers with poor tension on the side, for example, a nip roller or a suction roll can be used as the tension segment roller. In addition, the "downstream side" in the present invention means the downstream side in the conveying direction of the polarizer or the original film. According to the present invention, in the first control step, the peripheral speed of the first tension segment roller is controlled so that the tension measured by the tension meter arranged on the downstream side of the first tension segment roller becomes a predetermined value (hereinafter This is appropriately called "fixed tension control"). That is, since the circumferential speed of the first tension segment roller is controlled so that the actually measured tension becomes a predetermined value, even if the moisture content of the polarizer on the delivery side of the oven is low, the polarizer actually produces The fluctuation of the tension will still be reduced, which can stabilize the conveying of the polarizer.

Ideally, a plurality of the tension meters and the first tension segment rollers are alternately arranged between the processing tank and the laminating roller, and in the first control step, the tension meters are arranged on the most downstream side. After the peripheral speed is controlled by the combination of the aforementioned first tension segment roller, the combination of the aforementioned tension meter and the aforementioned first tension segment roller arranged on the upstream side than the aforementioned combination arranged on the most downstream side will move toward The upstream side implements weekly speed control in sequence.

In the above ideal method, the "upstream side" means the upstream side in the conveying direction of the polarizer or the original film. In addition, in the above ideal method, "peripheral speed control by the combination of the tensiometer and the first tension segment roller arranged on the most downstream side" means to use the tension gauge arranged on the most downstream side. The peripheral speed of the first tension segment roller arranged on the most downstream side is controlled in such a way that the output tension becomes a predetermined value. Furthermore, in the above ideal method, "peripheral speed control by the combination of the aforementioned tension meter and the aforementioned first tension segment roller arranged on the upstream side than the combination arranged on the most downstream side" means to make The tension measured by the tension meter arranged on the upstream side of the tension meter arranged on the most downstream side becomes a predetermined value to control the tension meter arranged on the upstream side of the tension meter and closest to the tension meter. 1 Peripheral speed of tension segment roller. In addition, in the above-mentioned ideal method, "sequential execution toward the upstream side" means from the peripheral speed control performed by the combination of the tension meter arranged on the most downstream side and the first tension segment roller, in order toward the upstream side. It is executed until the peripheral speed control is performed by the combination of the tension meter arranged on the most upstream side and the first tension segment roller. For example, when three sets of first tension segment rollers and tensiometers are arranged respectively (the tension meter 30a, the first tension segment roller 20a, the tension meter 30b, and the first tension segment are arranged in this order from the downstream side). When the segment roller 20b, the tension meter 30c, and the first tension segment roller 20c), it means that the peripheral speed of the first tension segment roller 20a is controlled so that the tension measured by the tension meter 30a becomes a predetermined value, The peripheral speed of the first tension segment roller 20b is controlled so that the tension measured by the tension meter 30b becomes the predetermined value, and then the first tension is controlled so that the tension measured by the tension meter 30c becomes the predetermined value. The peripheral speed of the tension segment roller 20c. According to the above ideal method, when a plurality of tensiometers and the first tension segment roller are alternately arranged, the peripheral speed is controlled by the combination of the tension meter and the first tension segment roller arranged on the most downstream side, and then sequentially The peripheral speed is controlled toward the combination arranged on the upstream side, so the peripheral speed can be controlled stably without diverging the control. Thereby, when a plurality of tension meters and the first tension segment rollers are alternately arranged, the fluctuation of the tension actually generated by the polarizer can be reduced, and the conveyance of the polarizer can be stabilized.

Moreover, the ideal practice is to arrange the first tension segment roller on the delivery side of the processing tank, and arrange a second tension segment roller for conveying the original film in the processing tank, and include a second control step. The second control step is to measure the peripheral speed of the first tension segment roller arranged on the delivery side of the processing tank after the first control step is executed, and to set the circumference of the first tension segment roller measured in the foregoing The ratio of the speed to the peripheral speed of the second tension segment roller becomes a predetermined value, and the peripheral speed of the second tension segment roller is controlled.

In the present invention, the peripheral speed of the first tension segment roller is controlled by a fixed tension control method. Therefore, the peripheral speed of the first tension segment roller arranged on the delivery side of the processing tank is not fixed but fluctuates. The situation is different when controlled by a fixed ratio control method. According to the above ideal method, in the second control step, basically, the ratio of the peripheral speed of the first tension segment roller to the peripheral speed of the second tension segment roller arranged on the delivery side of the processing tank is set in advance It controls the peripheral speed of the second tension segment roller, that is, implements a fixed ratio control. However, since the peripheral speed of the first tension segment roller placed on the delivery side of the processing tank used as the basis of the ratio is the actual measured peripheral speed, even if the first tension roller is placed on the delivery side of the processing tank as described above, the peripheral speed is The peripheral speed of the section rollers can still be controlled appropriately by a fixed ratio, and the original film can be stretched according to the predetermined stretching ratio set in advance.

The present invention is suitably used when the moisture content of the polarizer on the delivery side of the oven is 15% or less. That is, it is suitable for use with a polarizer that hardly expands or contracts due to its low moisture content. In addition, the "moisture content of the polarizing material" means the ratio of moisture in the polarizing material after drying in an oven. Specifically, the weight of the polarizer after drying in an oven (the weight of the polarizer after drying) and the weight of the polarizer after substantially removing moisture from the dried polarizer (the weight of the polarizer after complete drying) are measured. The weight of the polarizer), and substituting each weight into the following equation to calculate. The moisture content of the polarizer = (the weight of the polarizer after drying-the weight of the polarizer after completely drying) / the weight of the polarizer after drying × 100

The present invention is suitable for use when the thickness of the polarizer on the delivery side of the oven is 20 μm or less. That is, it is suitable for a polarizer that is thin and easily breaks due to excessive tension.

In addition, in order to solve the aforementioned problems, the present invention also provides a polarizing film manufacturing device, including: a processing tank, which dyes the original film with a dichroic substance and simultaneously performs uniaxial stretching; an oven, which is placed in the processing tank After the intermediate treatment, the original plate film is dried to produce a polarizer; the laminating roller is for laminating the aforementioned polarizer and the protective film; and the first tension segment roller is arranged between the aforementioned processing tank and the aforementioned laminating roller And used for conveying the polarizer; and the manufacturing device is provided with: a tensiometer, which is arranged between the processing tank and the bonding roller and on the downstream side of the first tension segment roller; and a control device; The control device controls the peripheral speed of the first tension segment roller so that the tension measured by the tension meter becomes a predetermined value.

In addition, in order to solve the aforementioned problems, the present invention also provides a control system for the aforementioned polarizing film manufacturing device, and the control system includes the aforementioned tensiometer and the aforementioned control device.

Invention effect According to the present invention, even if the moisture content of the polarizer on the delivery side of the oven is low, the transportation of the polarizer between the processing tank and the bonding roller can be stabilized.

The form used to implement the invention Hereinafter, the manufacturing method of the polarizing film, the manufacturing apparatus and the control system of the polarizing film of an embodiment of the present invention will be described with reference to the accompanying drawings. In addition, in this specification, the numerical range shown by "lower limit X-upper limit Y" means that the lower limit X is higher than the upper limit Y and the upper limit Y is lower. When multiple numerical ranges are described above, any lower limit value and any upper limit value can be selected to set "arbitrary lower limit value ~ arbitrary upper limit value". In addition, each drawing is for reference. Please note that the size, scale, and shape of the components shown in each drawing may be different from the actual ones. In addition, in the following description, "the manufacturing method of a polarizing film" and "the manufacturing apparatus of a polarizing film" may be abbreviated as "manufacturing method" and "manufacturing apparatus", respectively.

FIG. 1 is a diagram schematically showing a schematic configuration example of a manufacturing apparatus of a polarizing film, which uses the method of manufacturing a polarizing film of this embodiment. Fig. 2 is a diagram showing more specifically the part of the control system of this embodiment in the manufacturing apparatus of the polarizing film shown in Fig. 1. The arrows shown in Fig. 1 and Fig. 2 indicate the conveying direction of each film. As shown in FIG. 1 or FIG. 2, the manufacturing device of this embodiment is a roll-to-roll manufacturing device. The roll-to-roll method is a series of steps from manufacturing the polarizer F1 to at least following the protective film F2 to obtain the polarizing film F The way it is carried out on a manufacturing line. The manufacturing device of this embodiment is equipped with: a processing tank 2, which dyes the original film F0 with a dichroic substance and simultaneously uniaxially stretches it; an oven 3, which is used to dry the original film F0 processed in the processing tank 2 The polarizer F1 is produced; the laminating roller 7 is for laminating the polarizer F1 and the protective film F2; and the first tension segment roller 20 is arranged between the processing tank 2 and the laminating roller 7 and used for Convey the polarizer F1. The first tension segment rollers 20 of the present embodiment are arranged in multiple groups. Specifically, as shown in FIG. 2, three sets of first tension segment rollers 20 a to 20 c are sequentially arranged as the first tension segment rollers 20 from the downstream side (the downstream side in the transport direction of the polarizer F1 ). The first tension segment rollers 20 of this embodiment are all nip rollers. However, the present invention is not limited to the above, and two or more sets of first tension segment rollers 20 may be arranged, or only one set of first tension segment rollers 20 may be arranged. In addition, the first tension segment roller 20 may be another type of roller such as a suction roller.

Moreover, the manufacturing apparatus of this embodiment is equipped with the tension meter 30 which is arrange|positioned between the processing tank 2 and the bonding roller 7 and on the downstream side of the 1st tension segment roller 20. As shown in FIG. The tension meter 30 of the present embodiment is arranged in plural (the same number as the first tension segment roller 20). Specifically, as shown in FIG. 2, three tensiometers 30 a to 30 c are sequentially arranged as tensiometers 30 from the downstream side. The reason is that three sets of the first tension segment roller 20 are arranged. More specifically, the three tension meters 30a-30c are alternately arranged with the three sets of first tension segment rollers 20a-20c. That is, the tension meter 30a is arranged on the downstream side of the first tension segment roller 20a, and the tension meter 30b is arranged on the downstream side of the first tension segment roller 20b (upstream side of the first tension segment roller 20a). The gauge 30c is arranged on the downstream side of the first tension segment roller 20c (the upstream side of the first tension segment roller 20b). For the tension meter 30, for example, a micro-offset tension detector "LX-100TD" manufactured by Mitsubishi Electric Corporation, which uses a micro-displacement method as the measurement principle, can be used.

In addition, the manufacturing apparatus of this embodiment includes a control device 40. The control device 40 is composed of a computer and a PLC (Programmable Logic Controller). In addition, the manufacturing apparatus of the present embodiment includes an encoder 70 for measuring the number of rotations of the first tension segment roller 20 c arranged on the delivery side of the processing tank 2. The control system 100 of the present embodiment has a configuration including the tension meter 30, the control device 40, and the encoder 70 described above.

In addition, the manufacturing apparatus of the present embodiment includes a second tension segment roller 60 for conveying the original sheet film F0 in the processing tank 2. The second tension segment roller 60 of the present embodiment is arranged in multiple groups. Specifically, as shown in FIG. 2, five sets of second tension segment rollers 60 a to 60 e are sequentially arranged as the second tension segment rollers 60 from the upstream side (the upstream side in the conveying direction of the original sheet film F0 ). For the sake of illustration, the structure of the treatment tank 2 in FIG. 2 is simplified and shown as a single tank, but in fact, the treatment tank 2 of this embodiment consists of a swelling treatment tank, a dyeing treatment tank, and a dyeing treatment tank in order from the upstream side. The cross-linking treatment tank, the stretching treatment tank, and the washing treatment tank are composed of five divided tanks. The second tension segment roller 60a is arranged on the entrance side of the swelling processing tank, and the second tension segment roller 60b is arranged On the entrance side of the dyeing treatment tank, the second tension segment roller 60c is arranged on the entrance side of the cross-linking treatment tank, the second tension segment roller 60d is arranged on the entrance side of the extension processing tank, and the second tension segment roller 60e It is arranged on the entry side of the washing treatment tank. The second tension segment rollers 60 of this embodiment are all nip rollers. However, the present invention is not limited to the above, and two, three, four, or six or more sets of second tension segment rollers 60 may be arranged, or only one set of second tension segment rollers 60 may be arranged. In addition, the second tension segment roller 60 may be another type of roller such as a suction roller.

In addition to the components described above, the manufacturing apparatus of this embodiment includes various conventionally known components that are provided in general polarizing film manufacturing apparatuses.

To manufacture the polarizing film F using the manufacturing apparatus of this embodiment described above, first, the original film F0 wound on the discharge roll 1 is discharged and immersed in the treatment tank 2 (in this embodiment, the original film F0 is removed from the original film). From the upstream side in the conveying direction of F0, it is composed of a swelling treatment tank, a dyeing treatment tank, a cross-linking treatment tank, an extension treatment tank, and a washing treatment tank in order, with dichroic properties such as iodine or dichroic dyes. The material is dyed while being uniaxially stretched. Then, it was dried by the oven 3, and the polarizer F1 was obtained. The polarizer F1 is an optical element that only transmits light that vibrates in a specific direction (polarized light) and can shield light that vibrates in directions other than the specific direction. The polarizer F1 of this embodiment is a soft film shape.

The original film F0 is in the shape of a long strip. In this specification, the long strip shape means a rectangular shape in which the length in the long side direction is much larger than the length in the short side direction (the direction orthogonal to the long side direction). The length in the longitudinal direction of the long strip shape is, for example, 10 m or more, and preferably 50 m or more. The original film F0 is not particularly limited. Due to the good dyeability brought about by the dichroic substance, it is preferable to use a film containing a hydrophilic polymer film (such as a polyvinyl alcohol film, etc.), more preferably a hydrophilic polymer film . The film containing the hydrophilic polymer film may include a film formed by laminating a hydrophilic polymer film and a non-hydrophilic polymer film. In this case, it is preferable that the surface and/or back area layer of the non-hydrophilic polymer film have a hydrophilic polymer film. In this case, the hydrophilic polymer film laminated on the surface and/or back surface of the non-hydrophilic polymer film may be a thin film with a thickness of about several μm.

The hydrophilic polymer film is not particularly limited, and conventionally known films can be used. Specifically, hydrophilic polymer films include, for example, polyvinyl alcohol (PVA)-based films, partially formalized PVA-based films, polyethylene terephthalate (PET) films, and ethylene-vinyl acetate copolymer-based films. Films, such partially saponified films, etc. Furthermore, in addition to these, polyene-oriented films such as dehydrated PVA or dehydrochloric acid-treated polyvinyl chloride, and stretch-oriented polyethylene-based films can also be used. Among them, in view of the good dyeability due to the dichroic substance, the PVA-based polymer film is preferred. The raw material polymer of the PVA-based polymer film can include, for example, a polymer that is saponified after the polymerization of vinyl acetate, and a copolymerizable monomer such as a small amount of unsaturated carboxylic acid or unsaturated sulfonic acid relative to vinyl acetate.的polymers, etc. The degree of polymerization of the PVA-based polymer is not particularly limited, but from the viewpoint of solubility in water, etc., it is preferably 500 to 10,000, and more preferably 1,000 to 6,000. In addition, the degree of saponification of the PVA-based polymer is preferably 75 mol% or more, and more preferably 98 mol% to 100 mol%. The thickness of the untreated original film F0 is not particularly limited, and is, for example, 15 μm to 110 μm.

The treatment tank 2 of this embodiment is composed of a swelling treatment tank, a dyeing treatment tank, a cross-linking treatment tank, an elongation treatment tank, and a washing treatment tank in order from the upstream side in the conveying direction of the original film F0 as described above, and Each groove has, for example, the following configuration.

＜Swelling treatment tank＞ The swelling treatment tank is a treatment tank containing a swelling treatment liquid. The swelling treatment liquid can swell the original sheet film F0. For the swelling treatment liquid, for example, water can be used. In addition, an appropriate amount of iodine compounds such as glycerin or potassium iodide may be added to the water and the resulting water may be made into a swelling treatment liquid. When glycerin is added, its concentration is preferably 5% by weight or less, and when iodine compounds such as potassium iodide are added, its concentration is preferably 10% by weight or less.

＜Dyeing treatment tank＞ The dyeing treatment tank is a treatment tank containing a dyeing treatment liquid. The dyeing treatment solution can dye the original film F0. Examples of the dyeing treatment solution include solutions containing dichroic substances as active ingredients. Examples of dichroic substances include iodine and organic dyes. It is preferable to use a solution in which iodine has been dissolved in a solvent for the dyeing treatment liquid. Generally, water is used as the solvent, but an organic solvent compatible with water can also be added. The concentration of iodine in the dyeing treatment solution is not particularly limited, and is preferably 0.01% by weight to 10% by weight, and is preferably in the range of 0.02% by weight to 7% by weight, more preferably 0.025% by weight to 5% by weight. In order to further improve the dyeing efficiency, an iodine compound can also be added to the dyeing treatment solution as required. Iodine compounds are compounds containing iodine and elements other than iodine in the molecule. Examples include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, and iodine. Calcium fluoride, tin iodide, titanium iodide, etc.

＜Cross-linking treatment tank＞ The cross-linking treatment tank is a treatment tank containing a cross-linking treatment liquid. The cross-linking treatment liquid can cross-link the dyed original film F0. The crosslinking treatment liquid may use a solution containing a boron compound as an active ingredient. For example, as the crosslinking treatment liquid, a solution obtained by dissolving a boron compound in a solvent can be used. Generally, water is used as the solvent, but an organic solvent compatible with water can also be added. Examples of boron compounds include boric acid and borax. The concentration of the boron compound in the cross-linking treatment solution is not particularly limited, and is preferably 1% to 10% by weight, preferably 2% to 7% by weight, more preferably 2% to 6% by weight. In addition, from the viewpoint of obtaining a polarizer with uniform optical characteristics, an iodine compound may be added to the cross-linking treatment solution as required.

＜Extension processing tank＞ The extension treatment tank is a treatment tank containing an extension treatment liquid. The extension treatment liquid is not particularly limited, and, for example, a solution containing a boron compound as an active ingredient can be used. As the extension treatment liquid, for example, a solution in which a boron compound and various metal salts, zinc compounds, etc. are dissolved in a solvent can be used as required. Generally, water is used as the solvent, but an organic solvent compatible with water can also be added. The concentration of the boron compound in the extension treatment solution is not particularly limited, and is preferably 1% by weight to 10% by weight, and more preferably 2% by weight to 7% by weight. From the viewpoint of inhibiting the elution of iodine adsorbed on the film, an iodine compound can also be added to the extension treatment solution as required.

＜Washing treatment tank＞ The washing treatment tank is a treatment tank containing a washing treatment liquid. The washing treatment liquid can wash the original film F0 after stretching. The washing treatment liquid is a treatment liquid for washing treatment liquids such as a dyeing treatment liquid or a cross-linking treatment liquid attached to the original sheet film F0. For the cleaning treatment liquid, water such as ion exchange water, distilled water, and pure water can be used.

The oven 3 is installed on the downstream side of the washing treatment tank constituting the treatment tank 2 described above. The oven 3 is set up to dry the processed film. In addition, although the treatment tank 2 of this embodiment has a swelling treatment tank, a dyeing treatment tank, a cross-linking treatment tank, an extension treatment tank, and a washing treatment tank, one or two of these treatment tanks may be omitted. On the other hand, the treatment tank 2 may further have an adjustment treatment tank (not shown). The adjustment treatment tank contains a treatment tank for the adjustment treatment liquid. The adjustment treatment tank can be arranged between the cross-linking treatment tank and the extension treatment tank, or between the extension treatment tank and the washing treatment tank. The adjustment treatment liquid is a solution for adjusting the color of the film to be equal, and a solution containing an iodine compound as an active ingredient can be used. The film-based polarizer F1 is obtained by drying the cleaned original film F0 in the oven 3. The thickness of the polarizer F1 on the delivery side of the oven 3 is not particularly limited. For example, when it is 20 μm or less, the manufacturing method of this embodiment can be suitably used. In addition, the moisture content of the polarizer F1 on the delivery side of the oven 3 is not particularly limited. For example, when it is 15% or less, the manufacturing method of this embodiment can be suitably used. For example, when the drying temperature in the oven 3 is 60° C. or more and the drying time is 30 seconds or more, the moisture content of the polarizer F1 on the delivery side of the oven 3 is likely to be 15% or less.

In addition, the polarizer F1 that can be suitably used in the present invention is not limited to a polarizer obtained by stretching a single layer of a film, and a polarizer obtained by stretching a laminate film coated with a PVA-based resin on a substrate may also be mentioned. Representative examples of the above-mentioned polarizers include Japanese Patent Laid-Open No. 51-069644, Japanese Patent Laid-Open No. 2000-338329, International Publication No. 2010/100917, Japanese Patent Laid-Open No. 2014-059328, and Japanese Patent Laid-Open The thin polarizing film described in the 2012-73563 Bulletin. These thin polarizing films can be obtained by a manufacturing method including a step of stretching a PVA-based resin layer and a resin substrate for stretching in the state of a laminate and a step of dyeing. According to this manufacturing method, even if the PVA-based resin layer is thin, it is supported by the resin base material for stretching, so it can be stretched without any problems such as breakage due to stretching.

Next, as shown in FIG. 1, an active energy ray-curable adhesive is applied to both surfaces of the polarizer F1 by the coater 6. In this embodiment, the coater 6 uses a gravure coater. In addition, an active energy ray-curable adhesive is applied to one side of the protective film F2 discharged from the discharge roller 5 by the coater 6. Then, the protective film F2 coated with the adhesive is bonded to both sides of the polarizer F1 coated with the adhesive by the bonding roller 7.

The adhesive applied by the coater 6 can use an active energy ray hardening type adhesive. As the active energy ray-curable adhesive, conventionally known materials can be used. Active energy ray curable adhesives generally include active energy ray curable components and polymerization initiators, and various additives may be included as required. Active energy ray curable components can be roughly classified into electron beam curability, ultraviolet curability, and visible light curability. In addition, the active energy ray curable component can be roughly classified into a radical polymerizable compound and a cation polymerizable compound from the viewpoint of the curing mechanism.

系化合物等。Examples of the radically polymerizable compound include compounds having a radically polymerizable functional group having carbon-carbon double bonds such as a (meth)acryloyl group and a vinyl group. In addition, either a monofunctional radical polymerizable compound or a bifunctional or more polyfunctional radical polymerizable compound can be used. Moreover, these radically polymerizable compounds can be used individually by 1 type or in combination of 2 or more types. The radically polymerizable compound is preferably a compound having a (meth)acryloyl group, and examples include (meth)acrylamide derivatives having a (meth)acryloylamino group, and a (meth)acryloyloxy group. The (meth)acrylate and so on. When a radical polymerizable compound is used as an active energy ray-curable adhesive, the polymerization initiator can be appropriately selected in accordance with the active energy ray. When the adhesive is cured by ultraviolet or visible light, a polymerization initiator that cracks by ultraviolet or visible light can be used. The polymerization initiator includes, for example, benzophenone-based compounds, aromatic ketone compounds, acetophenone-based compounds, aromatic ketal-based compounds, aromatic sulfochlorine-based compounds, and 9-oxysulfur 𠮿

Department of compounds and so on.

Examples of the cationically polymerizable compound include a monofunctional cationically polymerizable compound having one cationically polymerizable functional group in the molecule, and a multifunctional cationically polymerizable compound having two or more cationically polymerizable functional groups in the molecule. Examples of the cationically polymerizable functional group include an epoxy group, an oxetanyl group, and a vinyl ether group. Examples of the cationic polymerizable compound having an epoxy group include aliphatic epoxy compounds, alicyclic epoxy compounds, and aromatic epoxy compounds. The cationic polymerizable compound having an oxetanyl group includes 3-ethyl-3-hydroxymethyloxetane, 1,4-bis[(3-ethyl-3-oxetanyl)methyl Oxymethyl]benzene, 3-ethyl-3-(phenoxymethyl)oxetane and the like. Examples of the cationic polymerizable compound having a vinyl ether group include 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, and the like. When a cationic polymerizable compound is used as an active energy ray curable adhesive, a cationic polymerization initiator can be blended. The cationic polymerization initiator generates cationic species or Lewis acid by irradiating active energy rays such as visible rays, ultraviolet rays, and electron beams, and starts polymerization reaction with epoxy groups of the cationic polymerizable compound. As the cationic polymerization initiator, a photoacid generator and a photobase generator can be used.

In the present invention, an active energy ray hardening type adhesive that is hardened by light containing visible rays of 380 nm to 450 nm can also be used. In this case, it is preferable to use an active energy ray curable adhesive containing a radical polymerizable compound and a polymerization initiator. The active energy ray curable adhesive is disclosed in, for example, Japanese Patent Laid-Open No. 2018-092186, and the active energy ray curable adhesive of the present invention can use the active energy ray curable adhesive described in the above publication. In this specification, the reprinting of the above-mentioned bulletin is omitted for the sake of writing, but this specification directly incorporates the relevant description of the adhesive in the above-mentioned bulletin.

The coating thickness of the adhesive is not particularly limited, but if it is too small, the adhesive strength of the film will decrease, and if it is too large, the thickness of the polarizing film F will be relatively too large. From the above viewpoint, the thickness of the adhesive applied to the polarizer F1 and the protective film F2 is preferably 0.1 μm to 5 μm, respectively. In addition, the viscosity of the adhesive at the beginning of application is not particularly limited, but if it is too small or too large, the adhesiveness of the adhesive will decrease from the beginning of application. From the above point of view, the viscosity at 25°C at the beginning of the application of the adhesive should be adjusted to 1mPa·s~100mPa·s, and at the beginning of the application, the viscosity at 25°C should be adjusted to 10mPa·s~50mPa· s is better, and it is better to adjust to 15mPa·s~45mPa·s.

The protective film F2 is in the shape of a long strip. In addition, the protective film F2 is a film with lower hydrophilicity (having hydrophobicity) than the polarizer F1. The protective film F2 is preferably one that is excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, and isotropy. Examples include: polyester-based polymers such as polyethylene terephthalate and polyethylene naphthalate; cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose; polymethyl methacrylate Acrylic polymers such as esters; styrene polymers such as polystyrene and acrylonitrile-styrene copolymer (AS resin); and polycarbonate polymers. In addition, the following polymers can also be cited as examples of the polymers forming the protective film F2: polyethylene, polypropylene, cyclic or polyolefins having a norbornene structure, such as polyolefin polymers of ethylene-propylene copolymers , Vinyl chloride-based polymers, nylon or aromatic polyamides and other amide-based polymers, imine-based polymers, tungsten-based polymers, polyether ether-based polymers, polyetheretherketone-based polymers, and Benzene sulfide polymer, vinyl alcohol polymer, chlorinated vinylene polymer, vinyl butyral polymer, aryl ester polymer, polyoxymethylene polymer, epoxy polymer or the above-mentioned polymers The blends and so on. The protective film F2 may contain one or more arbitrary and appropriate additives. Examples of additives include ultraviolet absorbers, antioxidants, slip agents, plasticizers, mold release agents, anti-colorants, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like. The content of the above-mentioned thermoplastic resin in the protective film F2 is preferably 50-100% by weight, preferably 50-99% by weight, more preferably 60-98% by weight, particularly preferably 70-97% by weight. When the content of the thermoplastic resin in the protective film F2 is 50% by weight or less, the inherent high transparency of the thermoplastic resin may not be sufficiently exhibited.

In addition, as the protective film F2, a polymer film described in Japanese Patent Application Laid-Open No. 2001-343529, for example, a thermoplastic resin containing (A) having a substituted and/or unsubstituted imine group in the side chain, and A resin composition of a thermoplastic resin having a substituted and/or unsubstituted phenyl group and a nitrile group in the side chain. As a specific example, a film containing a resin composition of an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer may be mentioned. As the film, a film composed of a mixed extruded product of a resin composition or the like can be used. Due to the small phase difference and low photoelastic coefficient, these films can eliminate the unevenness caused by the strain of the polarizing film F, and have excellent humidification durability due to low moisture permeability.

Next, as shown in FIG. 1, the adhesive between the polarizer F1 and the protective film F2 is irradiated with active energy rays from the active energy ray irradiation device 8 to be cured, and then dried in an oven 9. The active energy ray can be appropriately selected according to the curability of the active energy ray hardening adhesive. Examples of active energy rays include electron beams, ultraviolet rays, and visible rays. Finally, the long strip-shaped surface protective film F3 released from the release roller 10 is laminated by the laminating roller 11 to one side of the polarizer F1 with the protective film F2 laminated on both sides, thereby obtaining a long strip Polarizing film F. The obtained polarizing film F is taken up by the take-up roller 12.

In addition, in the example shown in FIG. 1, both the polarizer F1 and the protective film F2 are coated with an active energy ray-curable adhesive, but the adhesive may be coated only on both sides of the polarizer F1. In this case, out of the total of four coaters 6 shown in FIG. 1, the two coaters 6 on the lower side of FIG. 1 (the downstream side in the conveying direction of the polarizer F1) are not required. In addition, the adhesive may be applied to only one side of the protective film F2. In this case, out of the total of four coaters 6 shown in FIG. 1, the two coaters 6 on the upper side of FIG. 1 (the upstream side in the conveying direction of the polarizer F1) are not required. In addition, since the example shown in FIG. 1 is to laminate the protective film F2 on both sides of the polarizer F1, a pair of coaters 6 are arranged on the left and right sides of FIG. 1 and a pair of active energy ray irradiation devices 8 are arranged on the left and right sides. When the protective film F2 is laminated on one side of the piece F1, only one coater 6 and active energy ray irradiation device 8 may be arranged on either side of the left and right sides of FIG. 1.

Hereinafter, the operation of the control system 100 of this embodiment will be described. The control device 40 included in the control system 100 controls the peripheral speed of the first tension segment roller 20 so that the tension measured by the tension meter 30 becomes a predetermined value (corresponding to the first control step of the present invention). Specifically, during the production of the polarizing film F, the tension meter 30 continuously measures the tension of the polarizer F1 and outputs it to the control device 40. Furthermore, as shown in FIG. 2, the control device 40 controls the peripheral speed of the first tension segment roller 20a so that the tension Ta input from the tension meter 30a arranged on the most downstream side becomes a predetermined value (fixed tension control ). Specifically, when the input tension Ta is smaller than the value stored in the control device 40 and set in advance, the control device 40 sends a control signal to the drive unit (motor not shown in the figure) of the first tension segment roller 20a, So that the peripheral speed of the first tension segment roller 20a becomes a higher peripheral speed P1a than the current one. Conversely, when the input tension Ta is greater than the value set in advance and stored in the control device 40, a control signal is sent to the driving part of the first tension segment roller 20a to make the peripheral speed of the first tension segment roller 20a Becomes the smaller weekly speed P1a.

Next, the control device 40 controls the peripheral speed of the first tension segment roller 20b (fixed) so that the tension Tb input from the closest tension meter 30b arranged on the upstream side of the tension meter 30a becomes a predetermined value. Tension control). Specifically, when the input tension Tb is smaller than the value previously set and stored in the control device 40, the control device 40 sends a control signal to the drive unit (motor not shown in the figure) of the first tension segment roller 20b, So that the peripheral speed of the first tension segment roller 20b becomes a higher peripheral speed P1b than the current one. Conversely, when the input tension Tb is greater than the value set in advance and stored in the control device 40, a control signal is sent to the driving part of the first tension segment roller 20b to make the peripheral speed of the first tension segment roller 20b Becomes the smaller weekly speed P1b.

Finally, the control device 40 controls the peripheral speed of the first tension segment roller 20c arranged on the delivery side of the processing tank 2 so that the tension Tc input from the tension meter 30c arranged on the most upstream side becomes a predetermined value. (Fixed tension control). Specifically, when the input tension Tc is smaller than the value previously set and stored in the control device 40, the control device 40 sends a control signal to the driving part (motor not shown in the figure) of the first tension segment roller 20c, So that the peripheral speed of the first tension segment roller 20c becomes a higher peripheral speed P1c than the current one. Conversely, when the input tension Tc is greater than the value set in advance and stored in the control device 40, a control signal is sent to the driving part of the first tension segment roller 20c to make the peripheral speed of the first tension segment roller 20c Becomes the smaller weekly speed P1c.

As described above, in the first control step, the control system 100 of the present embodiment is such that the tension measured by the tension meter 30 arranged on the downstream side of the first tension segment roller 20 becomes a predetermined value. The peripheral speed of the first tension segment roller 20 is controlled. That is, since the circumferential speed of the first tension segment roller 20 is controlled so that the actually measured tension becomes a predetermined value, even if the moisture content of the polarizing member F1 on the delivery side of the oven 3 is low, the polarizing member The fluctuation of the actual tension produced by F1 will still be reduced, and the conveying of the polarizer F1 can be stabilized. In addition, in the control system 100 of this embodiment, in the first control step, the peripheral speed P1a is controlled by the combination of the tension meter 30a and the first tension segment roller 20a arranged on the most downstream side, and the peripheral speed P1a is sequentially arranged in the The combination on the upstream side controls the peripheral speed until the peripheral speed P1c is controlled by the combination of the tension meter 30c and the first tension segment roller 20c arranged on the most upstream side. Therefore, it is possible to stably control the peripheral speed without diverging the control.

After the control system 100 of this embodiment executes the first control step described above, it measures the peripheral speed of the first tension segment roller 20c arranged on the delivery side of the processing tank 2, and divides the measured first tension The ratio of the peripheral speed of the segment roller P1c' to the peripheral speed of the second tension segment roller 60 becomes a predetermined value, and the peripheral speed of the second tension segment roller 60 is controlled (corresponding to the second control step of the present invention) . Specifically, during the production of the polarizing film F, the encoder 70 continuously measures the number of rotations of the first tension segment roller 20 c and outputs it to the control device 40. The control device 40 calculates the peripheral speed P1c' of the first tension segment roller 20c based on the input rotation number of the first tension segment roller 20c and the outer diameter of the first tension segment roller 20c stored in advance. Furthermore, as shown in FIG. 2, the control device 40 controls the second tension segment roller 20c such that the ratio of the peripheral speed P1c' of the second tension segment roller 60 to the peripheral speed of the second tension segment roller 60 becomes a predetermined value. The peripheral speed of the tension segment roller 60 (fixed ratio control). Specifically, if the peripheral speed of the second tension segment roller 60a is P2a, the peripheral speed of the second tension segment roller 60b is P2b, the peripheral speed of the second tension segment roller 60c is P2c, and the peripheral speed of the second tension segment roller 60c is P2c. The peripheral speed of the roller 60d is P2d and the peripheral speed of the second tension segment roller 60e is P2e, then the control device 40 sets P2a/P1c'=β1, P2b/P1c'=β2, P2c/P1c'=β3, P2d/P1c'=β4, P2e/P1c'=β5 (β1, β2, β3, β4, and β5 are predetermined constants) to determine the peripheral speeds P2a, P2b, P2c, P2d, and P2e, and for the second tension roller The driving parts of 60a-60e (motors not shown in the figure, etc.) send out control signals to make the second tension segment rollers 60a-60e rotate at the respective peripheral speeds P2a-P2e.

The control system 100 of this embodiment controls the peripheral speed of the first tension segment roller 20c by means of a fixed tension control in the first control step, so the first tension segment roller 20c is arranged on the delivery side of the processing tank 2 The weekly speed is not fixed but variable, which is different from the conventional control with a fixed ratio control method. In the second control step, the control system 100 of this embodiment basically sets the measured peripheral speed P1c' of the first tension segment roller 20c arranged on the delivery side of the processing tank 2 and the second tension segment The ratio of the peripheral speed of the roller 60 becomes a predetermined value, and the peripheral speed of the second tension segment roller 60 is controlled, that is, a fixed ratio control is implemented. However, since the peripheral speed of the first tension segment roller 20c arranged on the delivery side of the processing tank 2 used as a reference for the ratio is based on the actually measured peripheral speed P1c', even if it is arranged on the delivery side of the processing tank 2 as described above The peripheral speed P1c' of the first tension segment roller 20c varies, and the fixed ratio control can still be implemented appropriately, and the original sheet film F0 can be stretched according to a predetermined stretching ratio set in advance.

Example Hereinafter, examples and comparative examples are described to describe the present invention in more detail. However, the present invention is not limited by the following examples.

<Example> A 45 μm thick polyvinyl alcohol film (VF-PS-4500 manufactured by Kuraray CO., LTD.) with an average degree of polymerization of 2400 and a degree of saponification of 99.9 mol% was used as the original film F0, and the treatment was performed in the treatment tank 2. Specifically, in the processing tank 2, it is immersed in 30 degreeC warm water for 60 seconds, and it swells. Next, it was immersed in a 0.3% aqueous solution of iodine/potassium iodide (weight ratio=0.5/8), and the film was dyed while extending it to 3.5 times. Then, stretching was performed in a borate aqueous solution at 65°C so that the total stretching ratio became 6 times. After the above treatment was performed in the treatment tank 2, it was dried in an oven 3 at a drying temperature of 40°C for 3 minutes to obtain a PVA-based polarizer F1 with a thickness of 18 μm.

The moisture content of the polarizer F1 on the delivery side of the oven 3 was measured, and the result was 14%. The moisture content of the polarizer F1 is measured in the following way. Approximately 60 minutes after the operation of the apparatus, a square was cut out of an arbitrary position of the polarizer F1 immediately after being sent out from the oven 3 to obtain a sample piece. Quickly measure the weight of the cut specimen under standard conditions. Then, the sample piece was forced to dry at 120°C for 2 hours in a heating oven, and then the weight of the sample piece was quickly measured in a standard state. In addition, by this forced drying, it is estimated that the moisture contained in the sample piece almost disappears. Substitute the weight of the sample piece before forced drying (the weight of the polarizer F1 after drying) and the weight of the sample piece after forced drying (the weight of the polarizer F1 after complete drying) into the following formula to obtain the polarizer F1 The moisture rate. Moisture content of polarizer F1 = (weight of polarizer F1 after drying-weight of polarizer F1 after complete drying)/weight of polarizer F1 after drying×100

In the example, as shown in Figures 1 and 2, when the polarizer F1 is transported, a fixed tension control is performed and the polarizer F1 is checked for breakage. The fixed tension control system is arranged in the processing tank 2 and the bonding roller 7 The peripheral speed of the first tension segment roller 20 is controlled so that the tension measured by the tension meter 30 on the downstream side of the first tension segment roller 20 becomes a predetermined value. In addition, the fluctuation of the tension measured by the tension meter 30a shown in FIG. 2 was investigated. In addition, even if the fluctuation of the tension is measured by the tensiometers 30b and 30c, the amount of the fluctuation is the same as when measured with the tensiometer 30a.

＜Comparative example＞ In the comparative example, when the polarizer F1 is conveyed, a fixed ratio control is performed. The fixed ratio control is to make the peripheral speed of the bonding roller 7 and the first tension segment roller arranged between the processing tank 2 and the bonding roller 7 Except for this point, the peripheral speed of the first tension segment roller 20 was controlled by the ratio of the peripheral speed of 20 to a predetermined value. Except for this point, the presence or absence of breakage of the polarizer F1 was investigated under the same conditions as in the examples and the tension meter 30a was used. Changes in the measured tension.

Table 1 lists the results of the above test. As shown in Table 1, in the comparative example, the tension fluctuation was very large, and the polarizer F1 cracked within 1 hour from the start of transportation. On the other hand, in the Example, the tension fluctuation was small, and the polarizer F1 did not break. [Table 1]

1, 5, 10: release roller 2: processing tank 3, 9: oven 6: Coating machine 7,11: Laminating roller 8: Active energy ray irradiation device 12: take-up drum 20, 20a, 20b, 20c: the first tension section roller 30, 30a, 30b, 30c: Tensiometer 40: control device 50, 70: encoder 60, 60a, 60b, 60c, 60d, 60e: the second tension section roller 100, 100A: control system F: Polarizing film F0: Original film F1: Polarizing parts F2: Protective film F3: Surface protection film P0’, P1a, P1b, P1c, P2a, P2b, P2c, P2d, P2e: weekly speed P1a, P1b, P1c, P1c’: weekly speed Ta, Tb, Tc: Tension

FIG. 1 is a diagram schematically showing a schematic configuration example of a manufacturing apparatus of a polarizing film, which is a method of manufacturing a polarizing film according to an embodiment of the present invention. Fig. 2 is a diagram showing in more detail the part related to the control system in the manufacturing apparatus of the polarizing film shown in Fig. 1. Fig. 3 is a diagram schematically showing a schematic configuration example of a manufacturing device and a control system used in a conventional manufacturing method of a polarizing film of a roll-to-roll system.

(no)

Claims (7)

A manufacturing method of polarizing film. After dyeing the original film with dichroic substance in a processing tank and performing uniaxial stretching at the same time, it is dried in an oven to produce a polarizer, and the aforementioned polarizer is laminated with a laminating roller Parts and protective film to make polarizing film; In this manufacturing method, a first tension segment roller for conveying the polarizer is arranged between the processing tank and the bonding roller, and between the processing tank and the bonding roller and in the first tension segment roller Tensiometer is installed on the downstream side of the device; and The manufacturing method includes a first control step that controls the peripheral speed of the first tension segment roller so that the tension measured by the tension meter becomes a predetermined value. According to the method of manufacturing a polarizing film of claim 1, wherein a plurality of the tensiometers and the first tension segment roller are alternately arranged between the processing tank and the laminating roller; and In the first control step, after the peripheral speed is controlled by the combination of the tension meter and the first tension segment roller arranged on the most downstream side, the peripheral speed is controlled by the combination arranged on the most downstream side than the combination arranged on the most downstream side. The combination of the aforementioned tension meter and the aforementioned first tension segment roller on the upstream side sequentially controls the peripheral speed toward the upstream side. The method for manufacturing a polarizing film according to claim 1, wherein the first tension segment roller is arranged on the delivery side of the processing tank, and the second tension segment roller for conveying the original film is arranged in the processing tank; and The manufacturing method includes a second control step that measures the peripheral speed of the first tension segment roller arranged on the delivery side of the processing tank after the first control step is performed, and makes the measurement The ratio of the peripheral speed of the first tension segment roller to the peripheral speed of the second tension segment roller becomes a predetermined value, and the peripheral speed of the second tension segment roller is controlled. The method of manufacturing a polarizing film according to claim 1, wherein the moisture content of the polarizing member on the delivery side of the oven is 15% or less. The method for manufacturing a polarizing film according to claim 1, wherein the thickness of the polarizing member on the delivery side of the oven is 20 µm or less. A manufacturing device for polarizing film, including: a processing tank, which dyes the original film with a dichroic substance and simultaneously uniaxially stretches it; and an oven, which dries the original film processed in the aforementioned processing tank to produce polarized light A laminating roller, which is used for laminating the polarizing member and the protective film; and, the first tension segment roller is arranged between the processing tank and the laminating roller and used for conveying the polarizing member; and The manufacturing apparatus includes a tension meter which is arranged between the processing tank and the bonding roller and on the downstream side of the first tension segment roller; and Control device The control device controls the peripheral speed of the first tension segment roller so that the tension measured by the tension meter becomes a predetermined value. A control system used in the manufacturing device of the polarizing film as in claim 6; The control system includes the tension meter and the control device.

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