TW202237380A - Manufacturing method and manufacturing device of polarizer having pinch rollers composed of a driving roller and a driven roller arranged in a processing bath - Google Patents

Abstract

The object of the present invention is to provide a manufacturing method of a polarizer, which is capable of suppressing stretching cracks of an original membrane in a processing bath. As a solution, the manufacturing method of a polarizer of the present invention is to arrange pinch rollers 2 in a processing bath L. While conveying the original membrane F0 is conveyed by the pinch rollers, the original membrane F0 is processed in the processing bath so as to produce the polarizer F1. The pinch rollers are composed of a driving roller 21 and a driven roller 22, and the driven roller clamps the original membrane between the driven roller and the driving roller to convey. The surface hardness of the driving roller is different from that of the driven roller.

Description

Manufacturing method and manufacturing device of polarizer

The invention relates to a manufacturing method and a manufacturing device of a polarizer. In particular, the present invention relates to a method and apparatus for manufacturing a polarizer capable of suppressing elongation cracking of an original sheet film in a treatment bath. The raw film is treated in a treatment bath to manufacture a polarizer.

Conventionally, a polarizing film including a polarizer has been used as a constituent material of a liquid crystal display device or an organic EL display device. The polarizing film is composed of, for example, a polarizer dyed with a dichroic substance such as iodine and a protective film for protecting the polarizer. The long strip-shaped polarizing film is usually produced by laminating the long strip-shaped protective film on at least one side of the long strip-shaped polarizer in a roll-to-roll manner. The produced strip-shaped polarizing film is cut into the size or shape suitable for the application and used for liquid crystal display devices and the like.

The polarizer is produced by using a long strip-shaped polymer film as an original film, and immersing the original film in various treatment baths while conveying it in the longitudinal direction to perform various treatments. The treatment tanks used as storage treatment baths, for example, can be used sequentially from the upstream side of the conveying direction of the original film: the swelling treatment tank, which is used to perform swelling treatment on the original film; the dyeing treatment tank, which is used to perform the warp Swelled original film is dyed with dichroic substances such as iodine; cross-linking treatment tank is used to cross-link the dyed original film; stretching treatment tank is used to cross-link Stretching treatment is carried out on the original film of joint treatment; and a cleaning treatment tank is used to carry out cleaning (washing) treatment on the original film which has been subjected to stretching treatment (for example, refer to Patent Document 1).

In general, guide rolls disposed in the processing bath are used to convey the original film in the processing bath, but nip rolls disposed in the processing bath may also be used (for example, refer to Patent Document 2). The guide roller is a roller that touches one side of the original film. The nip roller is a roller composed of a driving roller and a driven roller. The driving roller is rotated by a driving source such as a motor. The driven roller rotates with the rotation of the driving roller and clamps the original film on the driven roller. Conveyor between the roller and the drive roller.

However, it is known that when an original film is conveyed using nip rolls disposed in a treatment bath, the original film may break when stretched, that is, a so-called stretch crack. prior art literature patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2004-341515 Patent Document 2: Japanese Patent Laid-Open No. 2014-142392

The problem to be solved by the invention The present invention is made to solve the above-mentioned problems of the prior art, and its object is to provide a method and a manufacturing device of a polarizer that can suppress the elongation and cracking of the original plate film in the treatment bath. Nip rolls are arranged in the middle, and while the original film is conveyed by the nip rolls, the original film is processed in the treatment bath, thereby manufacturing a polarizer.

means to solve problems In order to solve the aforementioned problems, the inventors of the present invention have actively studied and found that one of the reasons for the elongation cracking of the original sheet film is as follows: if the surface hardness (outer surface hardness) of the driving roller and driven roller constituting the nip roller is high, the When the original film is clamped (when the original film is sandwiched between the driving roller and the driven roller in the state of pressing the original film), the linear pressure acting on the original film from the nip roller will increase. In order to reduce the linear pressure acting on the original film from the nip roller, it is also considered to reduce the surface hardness of both the driving roller and the driven roller. However, if the surface hardness is lowered, the durability of the nip roll will decrease due to immersion in the bath, so it is not preferable. Therefore, it is found that if the surface hardness of only one of the driving roller and the driven roller is reduced, the linear pressure acting on the original film from the nip roller will be reduced, and the elongation cracking of the original film can be suppressed, and the durability of the nip roller can be reduced. Sex can also be maintained at a level where no problems arise. The present invention was accomplished in view of the above findings of the present inventors.

That is, in order to solve the aforementioned problems, the present invention provides a method of manufacturing a polarizer, which comprises disposing nip rolls in a treatment bath, and while conveying the original film by the nip rolls, processing the original film in the treatment bath, In this way, polarizers are manufactured; the nip roller is composed of a driving roller and a driven roller, and the driven roller is used to convey the original plate film between the driven roller and the driving roller; the surface hardness of the driving roller and the The surface hardness of the aforementioned driven rollers is different.

In the present invention, "arranging the nip rolls in the treatment bath" means to arrange the nip rolls in a state where at least a part of the nip rolls is immersed in the treatment bath. According to the present invention, the surface hardness of the driving roller and the driven roller constituting the nip roller arranged in the treatment bath are different. In other words, among the driving roller and the driven roller, one roller has a high surface hardness, and the other roller has a low surface hardness. Therefore, as the inventors of the present invention have found, the linear pressure acting on the original film from the nip rolls can be reduced, so that the elongation cracking of the original film can be suppressed, and the durability of the nip rolls can also be maintained at a level that does not cause problems.

Preferably, the nip rolls are arranged so that a part of the driving roller is located above the liquid level of the treatment bath, and the driven roller is immersed in the treatment bath, and the surface hardness of the driving roller is lower than that of the aforementioned treatment bath. The surface hardness of the moving roller.

According to the above-mentioned preferable structure, the above-mentioned nip rollers are arranged so that a part of the driving roller is located above the liquid level of the treatment bath (in other words, the remaining part of the driving roller is immersed in the treatment bath), and the driven roller (from The moving drum as a whole) is immersed in the treatment bath. Therefore, it is not necessary to immerse the driving source such as a motor necessary for rotating the driving drum in a treatment bath (no need for waterproof treatment equipment for the driving source, etc.), and it is possible to reduce restrictions on equipment for manufacturing polarizers. Furthermore, according to the above preferred configuration, the surface hardness of a part of the drive roller located above the liquid level of the treatment bath is lower than the surface hardness of the driven roller immersed in the treatment bath. In other words, the entire driving roller, which has low surface hardness and poorer durability than the driven roller, does not need to be constantly immersed in the treatment bath, but is only partially and intermittently immersed as it rotates, so that the deterioration of the driving roller can be suppressed.

Among the above-mentioned driving roller and the aforementioned driven roller, the surface hardness of the roller with lower surface hardness is, for example, set to be less than 50 on the Shore A hardness scale, or less than 80 on the Asker C hardness scale, and the surface hardness of the roller with higher surface hardness The system is made to be 50 or more in Shore A hardness.

Preferably, the driving roller and/or the driven roller have a core material and a plurality of layers of elastic members wound on the core material, and the surface hardness of the elastic member of the inner layer of the plurality of layers of elastic members is higher than that of the inner layer of the plurality of layers of elastic members. The surface hardness of the elastic member of the outer layer.

In the above preferred method, "the surface hardness of the elastic member of the inner layer is higher than the surface hardness of the elastic member of the outer layer" means that when there are three or more elastic members wound on the core material, the comparison After any two layers of elastic members adjacent to each other in the radial direction of the core material (the radial direction of the driving roller and the driven roller), the surface hardness of the elastic members of the inner layer is higher than that of the outer layer. For example, when there are three layers of elastic members wound on the core material, the surface hardness of the elastic member located in the innermost layer becomes the highest value, the surface hardness of the elastic member located in the middle layer becomes the second highest value, and the surface hardness of the elastic member located in the innermost layer becomes the second highest value, and the elastic member located in the innermost layer becomes the second highest value. The surface hardness of the elastic member of the outer layer becomes the lowest value. Also, in the above preferred method, the surface hardness of the elastic members of each layer refers to the surface hardness in the following state: the elastic members are sequentially wound on the core material from the inner side, and the elastic members of each layer are located at the outermost state. For example, when there are three layers of elastic members wound on the core material, the surface hardness of the elastic member located in the innermost layer refers to the surface hardness measured in the state where only the elastic member is wound on the core material, and The state in which the elastic member is located on the outermost side (among the three layers of elastic members, the elastic member in the outermost layer and the elastic member in the middle layer are not yet wound). Also, the surface hardness of the elastic member of the middle layer refers to the surface hardness measured in the following state: the elastic member of the innermost layer is wound around the core material, and the elastic member of the middle layer is wound around the core material , and the elastic member is in the outermost state (among the three layers of elastic members, the elastic member in the outermost layer has not been wound). In addition, the surface hardness of the elastic member located in the outermost layer refers to the surface hardness measured in the state that the elastic member located in the innermost layer and the elastic member located in the middle layer are wound around the core material, and the elastic member located in the outermost layer The state in which the elastic member of the layer is wound on the core material. According to the above preferred method, the core material can be fully protected by the elastic member located in the innermost layer (the elastic member with the highest surface hardness), and the adhesive force when bonding the core material and the elastic member can be improved. In addition, since the elastic member (the elastic member with the lowest surface hardness) of the outermost layer contacts the original film, the linear pressure acting on the original film is reduced, thereby suppressing the stretching damage of the original film.

In the preferred method above, preferably, the plurality of layers of elastic members are three-layer elastic members.

According to the above preferred method, the core material can be sufficiently protected by the elastic member (the elastic member with the highest surface hardness) located in the innermost layer among the three elastic members, and the adhesive force between the core material and the elastic member can be improved. In addition, since the elastic member (the elastic member with the lowest surface hardness) of the outermost layer contacts the original film, the linear pressure acting on the original film is reduced, thereby suppressing the stretching damage of the original film. In addition, the surface hardness of the elastic member located in the outermost layer can be adjusted by the surface hardness of the elastic member located in the middle layer (an elastic member whose surface hardness shows an intermediate value).

Preferably, among the driving roller and the driven roller, the outer diameter of the roller with lower surface hardness is larger than the outer diameter of the roller with higher surface hardness.

According to the above preferred method, for example, when the nip rolls are arranged so that a part of the cylinder with lower surface hardness is located above the liquid level of the treatment bath and the cylinder with higher surface hardness is immersed in the treatment bath, due to the higher surface hardness, The outer diameter of the lower roller is large, so it is easy to make a part of the roller higher than the liquid level of the treatment bath. Thereby, deterioration of the said drum can be suppressed.

The method of the present invention can suppress the elongation cracking of the original film, so it can be suitably used when the treatment bath is a treatment bath for stretching the original film.

Also, in order to solve the aforementioned problems, the present invention also provides a polarizer manufacturing device, which is equipped with a treatment tank for storing a treatment bath and nip rollers disposed in the treatment bath; While processing the original film in the treatment bath, a polarizer is manufactured; the nip roller is composed of a driving roller and a driven roller, and the driven roller clamps the original film between the driven roller and the driving roller. Conveyor between the rollers; the surface hardness of the aforementioned driving roller is different from that of the aforementioned driven roller.

Invention effect According to the present invention, the method and device for manufacturing polarizers are to arrange nip rollers in the treatment bath and to transport the original film with the nip rollers while processing the original film in the treatment bath, thereby manufacturing polarizers, with the method and device In other words, the linear pressure acting on the original film from the nip roll will be reduced, and the stretching crack of the original film can be suppressed, and the durability of the nip roll can also be maintained at a level that does not cause problems.

Hereinafter, a manufacturing method and a manufacturing apparatus of a polarizer according to an embodiment of the present invention will be described with appropriate reference to the attached drawings. In addition, since the drawings are for reference only, it should be noted that the dimensions, scales, and shapes of members shown in the drawings may differ from actual ones.

FIG. 1 is a diagram schematically showing a schematic configuration of a manufacturing apparatus of a polarizer according to the present embodiment. Fig. 1(a) is a side view showing the overall schematic structure of the manufacturing device 100 (viewed from a horizontal direction perpendicular to the conveying direction of the original film F0 and polarizer F1), and Fig. 1(b) is Fig. 1(a) ) is an enlarged view of the elongation processing tank 14 shown. The thick arrow shown in FIG. 1 refers to the conveying direction of the original film F0 and the polarizer F1. As shown in FIG. 1, the manufacturing apparatus 100 of the present embodiment is equipped with: a plurality of processing tanks 1, which respectively store the processing bath L (in FIG. 1, the part with dotted hatching); It is arranged in a predetermined processing bath L (in this embodiment, a stretching treatment bath L4); the manufacturing device 100 processes the original sheet film F0 in the processing bath L (L1 to L5) while conveying the original sheet film F0 with nip rollers 2 or the like. Film F0 is subjected to processing to thereby manufacture a device of polarizer F1. The manufacturing apparatus 100 includes, in addition to the treatment tank 1 and the nip roll 2, a release roll FR around which the long original film F0 is wound, nip rolls NR and guide rolls for conveying the original film F0 released from the release roll FR. A roll GR and an oven 3 for drying the original film F0. In addition, for the polarizer F1 manufactured by the manufacturing apparatus 100, a protective film is attached to at least one side of the polarizer F1 through a UV-curable adhesive, and the adhesive is cured by an ultraviolet irradiation device to manufacture a polarizing film. And, for example, a polarizing plate is produced by laminating a surface protection film on one side of the polarizing film.

The original sheet film F0 uses a long strip-shaped polymer film. The polymer film forming the original sheet film F0 is not particularly limited, and various films can be used. Examples include polyvinyl alcohol (PVA)-based films, polyethylene terephthalate (PET)-based films, ethylene-vinyl acetate copolymer-based films, partially saponified films, cellulose-based films, etc. High polymer film, or polyene-based oriented film such as dehydration treatment of PVA or dehydrochlorination treatment of polyvinyl chloride, etc. Among them, it is preferable to use a PVA-based film which is excellent in dyeability due to iodine.

The polymerization degree of the polymer of the aforementioned polymer film material is generally 500-10000, preferably in the range of 1000-6000, more preferably in the range of 1400-4000. In addition, when the aforementioned polymer film is a saponified film, the degree of saponification is, for example, from the viewpoint of solubility in water, preferably at least 75 mol%, more preferably at least 98 mol%, and in the range of 98.3 to 99.8 mol. It is better within the range of ear %.

When a PVA-based film is used as the polymer film, the PVA-based film can be produced by any method such as casting, casting, and extrusion of a stock solution dissolved in water or an organic solvent to form a film. The retardation value of PVA film should be 5nm~100nm. Also, in order to obtain the in-plane uniform polarizer F1, the in-plane retardation of the PVA film should be as small as possible, and the in-plane retardation of the PVA film as the original film F0 should be less than 10nm at a measurement wavelength of 1000nm. It is preferably less than 5nm.

The original film F0 described above is wound on the discharge roller FR and arranged on the most upstream side of the manufacturing apparatus 100 (the most upstream side in the conveyance direction of the original film F0 ). Then, while conveying the original film F0 discharged from the discharge roller FR, the original film F0 is immersed in the processing bath L (L1 to L5) in the processing tank 1 to perform processing. In the manufacturing device 100 of the present embodiment, as the processing tank 1, it is provided sequentially from the upstream side of the conveying direction of the original film F0: a swelling processing tank 11 for performing swelling processing; a dyeing processing tank 12 for dyeing treatment; cross-linking treatment tank 13, which is used for cross-linking treatment; stretching treatment tank 14, which is used for stretching treatment; and washing treatment tank 15, which is used for washing processor. In addition, the order, number of times, and presence or absence of each treatment of swelling, dyeing, crosslinking, stretching, and washing in each treatment tank 1 are not particularly limited, and several treatments may be performed simultaneously in a single treatment tank 1, or several treatments may not be performed. processing. For example, stretching treatment can be performed immediately after dyeing treatment, or can be performed simultaneously with swelling treatment or dyeing treatment. In addition, dyeing treatment may be performed after stretching treatment.

In the swelling treatment tank 11 , for example, water can be used as the treatment bath L (swelling treatment bath L1 ). By immersing the original film F0 in the swelling treatment bath L1 and washing the original film F0 with water, the dirt or anti-adhesive agent on the surface of the original film F0 can be cleaned. In addition, by swelling the original film F0, an effect of preventing unevenness such as dyeing unevenness can be expected. Glycerin or potassium iodide can also be appropriately added to the swelling treatment bath L1, and the concentration of addition is preferably 5% by weight or less of glycerin and 10% by weight or less of potassium iodide. The temperature of the swelling treatment bath L1 is preferably in the range of 20-45°C, more preferably 25-40°C. The immersion time of the original sheet film F0 in the swelling treatment bath L1 is preferably 2-180 seconds, more preferably 10-150 seconds, especially 60-120 seconds. Also, the original sheet film F0 may be stretched in the swelling treatment bath L1, and the stretching ratio at this time is about 1.1 to 3.5 times in addition to the stretching by swelling.

In the dyeing treatment tank 12, for example, a treatment bath containing a dichroic substance such as iodine is used as a treatment bath L (dyeing treatment bath L2), and the original film F0 is immersed in the dyeing treatment bath L2 to make the dichroic substance Adsorbed to the original plate film F0.

As the aforementioned dichroic substance, conventionally known substances can be used, and examples thereof include iodine and organic dyes. Examples of organic dyes that can be used include red BR, red LR, red R, pink LB, purple BL, burgundy GS, sky blue LG, tartrazine, blue BR, blue 2R, navy blue RY, green LG, purple LB, Purple B, Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Bright Purple BK, Supra Blue G, Supra Blue GL, Supra Orange GL , direct sky blue, direct fast orange S, fast black, etc.

These dichroic substances may be used alone or in combination of two or more. When using the aforementioned organic dyes, it is preferable to combine two or more organic dyes from the viewpoint of neutralization in the visible light region, for example. Specific examples include the combination of Congo Red and Supra Blue G, the combination of Supra Orange GL and Direct Sky Blue, or the combination of Direct Sky Blue and Fast Black.

A solution in which the aforementioned dichroic substance has been dissolved in a solvent can be used as the dyeing treatment bath L2. The aforementioned solvent is generally water, but an organic solvent compatible with water may be further added. The concentration of the dichroic substance is preferably in the range of 0.010-10% by weight, more preferably in the range of 0.020-7% by weight, especially 0.025-5% by weight.

Also, when iodine is used as the aforementioned dichroic substance, it is preferable to further add iodide from the viewpoint that the dyeing efficiency can be further improved. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, titanium iodide and the like. The addition ratio of these iodides in the dyeing bath L2 is preferably 0.010-10% by weight, more preferably 0.10-5% by weight. Potassium iodide should be added to these, and the ratio (weight ratio) of iodine to potassium iodide should be in the range of 1:5~1:100, more preferably in the range of 1:6~1:80, especially in the range of 1:7 ~1:70 range.

The immersion time of the original film F0 in the dyeing treatment bath L2 is not particularly limited, and is preferably in the range of 1 to 20 minutes, more preferably 2 to 10 minutes. Also, the temperature of the dyeing treatment bath L2 is preferably within the range of 5-42°C, more preferably within the range of 10-35°C. In addition, the original sheet film F0 may also be stretched in the dyeing treatment bath L2, and the accumulated total stretching ratio at this time is about 1.1 to 4.0 times.

In addition, as the dyeing treatment, in addition to the above-mentioned method of immersing in the dyeing treatment bath L2, for example, a method of coating or spraying an aqueous solution containing a dichroic substance on the original film F0 can also be used to form a film on the original film F0. When pre-mixed with dichroic substances.

In the crosslinking treatment tank 13, the original film F0 is immersed in the treatment bath L (crosslinking treatment bath L3) containing a crosslinking agent, thereby crosslinking the original film F0. As the crosslinking agent, conventionally known ones can be used, and examples thereof include boron compounds such as boric acid and borax, glyoxal, and glutaraldehyde. These may be used alone or in combination of two or more. When two or more types are used together, for example, the combination of boric acid and borax is suitable, and the addition ratio (mole ratio) should be within the range of 4:6~9:1, more preferably within the range of 5.5:4.5~7:3 , the optimum is 6:4.

As the crosslinking treatment bath L3, a solution obtained by dissolving the aforementioned crosslinking agent in a solvent can be used. The aforementioned solvent can be water, for example, and may further include an organic solvent compatible with water. The concentration of the cross-linking agent in the aforementioned solution is not limited thereto, preferably in the range of 1-10% by weight, more preferably 2-6% by weight.

From the viewpoint of obtaining the in-plane uniform characteristics of the polarizer F1, iodide may also be added to the crosslinking treatment bath L3. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, titanium iodide, and The content is 0.05-15% by weight, more preferably 0.5-8% by weight. Among them, a combination of boric acid and potassium iodide is preferable, and the ratio (weight ratio) of boric acid to potassium iodide is preferably in the range of 1:0.1~1:3.5, more preferably in the range of 1:0.5~1:2.5.

The temperature of the cross-linking treatment bath L3 is usually in the range of 20-70°C, and the immersion time of the original film F0 is usually in the range of 1 second to 15 minutes, preferably 5 seconds to 10 minutes. In addition, the method of applying or spraying a solution containing a crosslinking agent can also be used for the crosslinking treatment similarly to the dyeing treatment. In addition, the original sheet film F0 can also be stretched in the cross-linking treatment bath L3, and the cumulative total stretching ratio at this time is about 1.1 to 4.0 times.

In the stretching treatment tank 14 , the original film F0 is stretched to a cumulative total stretching ratio of about 2 to 7 times while the original film F0 is immersed in the treatment bath L (stretching treatment bath L4 ).

The stretching treatment bath L4 is not particularly limited thereto, for example, various metal salts, or solutions added with compounds of iodine, boron, or zinc can be used. As a solvent for this solution, water, ethanol, or various organic solvents can be used appropriately. Among them, it is also preferable to use a solution in which boric acid and/or potassium iodide are added in an amount of about 2 to 18% by weight. When this boric acid and potassium iodide are used together, the content ratio (weight ratio) is preferably about 1:0.1 to 1:4, more preferably about 1:0.5 to 1:3.

The temperature of the stretching treatment bath L4 is, for example, preferably in the range of 40-67°C, more preferably 50-62°C.

In the cleaning treatment tank 15, for example, by immersing the original film F0 in the treatment bath L (cleaning treatment bath L5) of an aqueous solution, unnecessary residues such as boric acid adhering to the original film F0 in the previous treatment can be washed away. . Iodide may also be added to the above aqueous solution, for example sodium iodide or potassium iodide may be preferably used as iodide. When potassium iodide is added to cleaning treatment bath L5, its concentration is usually 0.1 to 10% by weight, preferably 3 to 8% by weight. In addition, the temperature of the cleaning treatment bath L5 is preferably 10 to 60°C, more preferably 15 to 40°C. In addition, the number of times of the cleaning treatment is not particularly limited and may be performed plural times, and the kind or concentration of the additive in each cleaning treatment bath L5 in this case may also be changed.

Moreover, in this embodiment, since the nip roll NR is arrange|positioned at the exit side of each processing tank 1, when pulling up the original film F0 from each processing tank 1, dripping can be prevented from occurring.

Drying treatment is performed on the original film F0 that has been treated in the treatment bath L of each treatment tank 1 described above. Appropriate methods such as natural drying, air drying, and heat drying can be used for drying treatment, and heat drying is generally suitable. The manufacturing device 100 of the present embodiment uses the oven 3 to heat and dry. In the oven 3, for example, the heating temperature is preferably about 20 to 80° C., and the drying time is about 1 to 10 minutes. Moreover, regardless of the aforementioned method, from the viewpoint of preventing the deterioration of the polarizer F1, the drying temperature should be set as low as possible. It is more preferably below 60°C, especially preferably below 45°C.

Compared with the original film F0 before treatment, the final total elongation ratio of the polarizer F1 manufactured by the above method is preferably 3.0~7.0 times, more preferably in the range of 5.5~6.2 times. If the final total stretching ratio is less than 3.0 times, it will be difficult to obtain the polarizer F1 with high polarization degree, and if it is more than 7.0 times, the original film F0 will be easily broken.

The manufacturing apparatus 100 of this embodiment is equipped with the nip roll 2 arrange|positioned in the processing bath L. As shown in FIG. In the present embodiment, the nip roll 2 is disposed in the drawing treatment bath L4 stored in the drawing treatment tank 14 in the treatment tank 1 . Moreover, in this embodiment, two sets of nip rollers 2 (2a, 2b) are arranged along the conveyance direction of the original sheet film F0. As shown in FIG. 1( b ), the nip roller 2 is composed of a driving roller 21 and a driven roller 22 , and the driven roller 22 is for conveying the original film F0 between the driven roller 22 and the driving roller 21 . Hereinafter, the structure of the nip roll 2 of this embodiment is demonstrated more concretely.

The nip roller 2 of this embodiment is characterized in that the surface hardness of the drive roller 21 and the surface hardness of the driven roller 22 are different. In this embodiment, the surface hardness of the drive roller 21 is set lower than the surface hardness of the driven roller 22 . And, as shown in FIG. 1( b ), in this embodiment, the nip roller 2 is arranged so that the driving roller 21 and the driven roller 22 face up and down, and the driving roller 21 is located above the driven roller 22 . In addition, the nip roll 2 is arranged such that a part of the driving roll 21 is located above the liquid level of the drawing bath L4, and the driven roll 22 is immersed in the drawing bath L4. Specifically, it is arranged so that the shaft portion 211a of the driving drum 21 is positioned higher than the liquid surface of the stretching bath L4.

As above, the surface hardness of the driving roller 21 is different from that of the driven roller 22 (specifically, the surface hardness of the driving roller 21 is lower than that of the driven roller 22), so the line acting on the original film F0 from the nip roller 2 The pressure is lowered, and the stretching crack of the original film F0 can be suppressed, and the durability of the nip roll 2 can also be maintained at a level that does not cause problems. In addition, since a part of the driving drum 21 is located above the liquid level of the stretching bath L4, it is not necessary to immerse a driving source (not shown) such as a motor necessary for rotating the driving drum 21 in the stretching bath L4. There are few restrictions on the equipment for manufacturing the polarizer F1. In addition, a part of the driving roller 21 whose surface hardness is lower than that of the driven roller 22 is located higher than the liquid level of the stretching bath L4, so the driving roller 21 as a whole does not need to be constantly immersed in the stretching bath L4, and only partly changes with rotation. Moreover, the impregnation is intermittent, so the deterioration of the drive roller 21 can be suppressed.

FIG. 2 is a diagram schematically showing a schematic configuration of a drive roller 21 according to the present embodiment. Fig. 2 (a) is a side view (viewed from a horizontal direction perpendicular to the conveying direction of the original plate film F0 and polarizer F1 shown in Fig. 1), and Fig. 2 (b) is a front sectional view (from Fig. 1 1 shows the cross-sectional view through the center of the driving roller 21 viewed from the conveying direction of the original film F0 and the polarizer F1). As shown in FIG. 2 , the drive roller 21 of this embodiment includes a core material 211 and multiple layers of elastic members 212 wound on the core material 211 .

The core material 211 of this embodiment has a shaft portion 211a with a circular cross section and a tubular portion 211b with a circular cross section. A driving source (not shown) is connected to the shaft portion 211a, and the shaft portion 211a is rotated by the rotational driving force supplied from the driving source. The central axis of the shaft portion 211 a becomes the rotational central axis of the driving drum 21 . The tubular portion 211b is provided with a hollow portion at the center thereof, and is combined with the shaft portion 211a by fitting the shaft portion 211a into the hollow portion. As the shaft portion 211a rotates, the tubular portion 211b also rotates integrally with the shaft portion 211a. The materials of the shaft portion 211a and the tubular portion 211b are not particularly limited. For example, the shaft portion 211a is made of stainless steel (such as SUS316), and the tubular portion 211b is made of resin (such as CFRP). The outer diameter of the core material 211 (the outer diameter of the tubular portion 211 b ) is set to, for example, 400 to 600 mm.

In this embodiment, as the elastic member 212, three layers of elastic members 212a, 212b, and 212c are wound around the surface (outer surface) of the tubular portion 211b of the core material 211. The elastic member 212a of the innermost layer is bonded to the surface of the tubular portion 211b through a suitable adhesive. The elastic member 212b in the middle layer is bonded to the surface (outer surface) of the elastic member 212a through a suitable adhesive. The elastic member 212c of the outermost layer is bonded to the surface (outer surface) of the elastic member 212b through a suitable adhesive. The material of the elastic member 212a is not particularly limited, for example, the elastic member 212a is preferably formed of styrene-butadiene rubber (SBR). In addition, the elastic member 212a may be formed of acrylonitrile-butadiene rubber (NBR) or ethylene-propylene-diene rubber (EPDM). The thickness of the elastic member 212a is not particularly limited, preferably 0.5-5mm, more preferably 1.5-2mm. The material of the elastic member 212b is not particularly limited, for example, the elastic member 212b is preferably formed of EPDM. In addition, the elastic member 212b may also be formed from NBR or SBR. The thickness of the elastic member 212b is not particularly limited, and is preferably 1-10 mm, more preferably 6-6.5 mm. The material of the elastic member 212c is not particularly limited. For example, similar to the elastic member 212b, the elastic member 212c is preferably formed of EPDM. However, in order to reduce the surface hardness of the elastic member 212c, the elastic member 212c is preferably formed of EPDM foam. The EPDM foam can be produced, for example, by foaming EPDM with a foaming agent and crosslinking it with a crosslinking agent. The thickness of the elastic member 212c is not particularly limited, preferably 0.5-10 mm, more preferably 1-5 mm, especially 1.5-2.5 mm.

The three-layer elastic member 212 is set so that the surface hardness of the elastic member 212 of the inner layer is higher than the surface hardness of the elastic member 212 of the outer layer. That is, the surface hardness of the elastic member 212a located in the innermost layer becomes the highest value, the surface hardness of the elastic member 212b located in the middle layer becomes the second highest value, and the surface hardness of the elastic member 212c located in the outermost layer becomes the lowest value. value. Specifically, the surface hardness (outer surface hardness) of the elastic member 212 a is preferably 70-100 in Shore A hardness, more preferably 80-100, and especially preferably 90-100. The Shore A hardness can be measured using a commercially available durometer (Type A) conforming to JIS K6253 (1997). As the hardness tester (A type), for example, "ASKER-TYPE A (ASKER A-type hardness tester)" manufactured by Polymer Instruments Co., Ltd. can be used. Specifically, the surface hardness (outer surface hardness) of the elastic member 212 b is preferably 60-99, more preferably 70-90, especially 75-85 in terms of Shore A hardness. The surface hardness (outer surface hardness) of the elastic member 212c is preferably less than 50 on the Shore A durometer, or less than 80 on the Asker C durometer, preferably 10-40 on the Shore A durometer, or 100 on the Asker C durometer. 60~79, especially 20~30 by Shaw A hardness, and 65~75 by Asker C hardness. Asker C hardness can be measured using a commercially available hardness tester (Type C) conforming to JIS K7312 (1996). As a hardness tester (Type C), for example, "ASKER-TYPE C (ASKER C-type hardness tester)" manufactured by Polymer Instruments Co., Ltd. can be used. The surface hardness (outer surface hardness) of the drive roller 21 is represented by the surface hardness of the elastic member 212c located on the outermost layer. Therefore, the surface hardness of the driving drum 21 is preferably less than 50 on the Shore A hardness scale, or less than 80 on the Asker C hardness scale.

As mentioned above, the drive roller 21 of this embodiment has three layers of elastic members 212, wherein the surface hardness of the elastic members 212 of the inner layer is higher than the surface hardness of the elastic members 212 of the outer layer. Therefore, the core material 211 can be fully protected by the elastic member 212a located in the innermost layer with high surface hardness, and the adhesive force between the core material 211 and the elastic member 212a can be improved. In addition, since the elastic member 212c located on the outermost layer with low surface hardness contacts the original film F0, the linear pressure acting on the original film F0 is reduced, thereby suppressing stretching cracks of the original film F0. In addition, the surface hardness of the elastic member 212c on the outermost layer can be adjusted by the surface hardness of the elastic member 212b on the middle layer.

FIG. 3 is a diagram schematically showing a schematic configuration of the driven roller 22 of the present embodiment. Fig. 3 (a) is a side view (viewed from a horizontal direction orthogonal to the conveying direction of the original plate film F0 and polarizer F1 shown in Fig. 1), Fig. 3 (b) is a front sectional view (from Fig. 1 1 shows the cross-sectional view through the center of the driven roller 22 viewed from the conveying direction of the original film F0 and the polarizer F1). As shown in FIG. 3 , the driven roller 22 of the present embodiment includes a core material 221 and one layer of elastic members 222 wound around the core material 221 .

The core material 221 has the same configuration as the core material 211 of the drive roller 21 . That is, the core material 221 has a shaft portion 221 a with a circular cross section and a tubular portion 221 b with a circular cross section. The central axis of the shaft portion 221 a becomes the rotational central axis of the driven roller 22 . The tubular portion 221b is provided with a hollow portion at its center, and is combined with the shaft portion 221a by fitting the shaft portion 221a into the hollow portion. As the shaft portion 221a rotates, the tubular portion 221b also rotates integrally with the shaft portion 221a. The material of the shaft portion 221a and the tubular portion 221b is not particularly limited. For example, the shaft portion 221a is made of stainless steel (such as SUS316), and the tubular portion 221b is made of resin (such as CFRP). The outer diameter of the core material 221 (the outer diameter of the tubular portion 221 b ) is set to, for example, 400 to 500 mm.

The elastic member 222 is bonded to the surface of the tubular portion 221b through a suitable adhesive. The material of the elastic member 222 is not particularly limited, for example, the elastic member 222 is preferably formed of styrene-butadiene rubber (SBR). In addition, the elastic member 222 may also be formed from NBR or EPDM. The thickness of the elastic member 222 is not particularly limited, preferably 5-20 mm, more preferably 5-15 mm, especially 10 mm. In addition, the preferred thickness of the above-mentioned elastic member 222 is the thickness of the central portion of the driven roller 22 in the axial direction. Set convex. By setting the convex surface on the driven roller 22, when the driving roller 21 is pressed toward the driven roller 22, it is not easy to generate a gap above the thickness of the original film F0 between the driving roller 21 and the driven roller 22, so that it can be clamped reliably. Live original plate film F0 and convey.

The surface hardness (outer surface hardness) of the driven roller 22 is represented by the surface hardness (outer surface hardness) of the elastic member 222. Surface hardness). Therefore, the surface hardness of the elastic member 222 is preferably 50 or more in Shore A hardness.

In addition, in this embodiment, the outer diameter of the driving roller 21 is larger than the outer diameter of the driven roller 22 . For example, the outer diameter of the drive roller 21 is 500mm (the outer diameter of the core material 211 is 480mm+the thickness of the elastic member 212a is 1.5mm×2+the thickness of the elastic member 212b is 6.5mm×2+the thickness of the elastic member 212c is 2mm×2=500mm), The outer diameter of the driven roller 22 is 460mm (the outer diameter of the core material 221 is 440mm+the thickness of the elastic member 222 is 10mm×2=460mm). As described above, since the outer diameter of the driving roller 21 is large, a part of the driving roller 21 can be easily located above the liquid level of the elongation treatment bath L4, thereby suppressing deterioration of the driving roller 21 .

In the present embodiment described above, the case where the nip roll 2 is arranged such that a part of the driving roll 21 is located above the liquid level of the drawing bath L4 and the driven roll 22 is immersed in the drawing bath L4 has been described. , but the present invention is not limited thereto. The nip roll 2 may be arranged such that both the driving roll 21 and the driven roll 22 are immersed in the stretching bath L4. In addition, an aspect in which the vertical positional relationship between the driving roller 21 and the driven roller 22 is reversed may also be adopted. Specifically, the following aspect can also be adopted: the pinch roller 2 is arranged so that a part of the driven roller 22 is positioned higher than the liquid level of the stretching bath L4, and the driving roller 21 is immersed in the stretching bath L4. ; or the nip roller 2 is configured so that both the driven roller 22 located above and the driving roller 21 located below are immersed in the stretching treatment bath L4.

Also, in this embodiment, the case where the surface hardness of the driving roller 21 becomes lower than the surface hardness of the driven roller 22 has been described, but the present invention is not limited thereto, and the surface hardness of the driven roller 22 may also be used. The hardness is lower than that of the surface hardness of the drive roller 21 .

Also, in the present embodiment, the case where the drive roller 21 is equipped with three layers of elastic members 212 has been described, but the present invention is not limited thereto, and a state of having two or more layers of elastic members 212 of more than four layers may also be adopted. Sample. Also, the driven roller 22 and the driving roller 21 can also be equipped with a plurality of layers of elastic members 222 (that is, the driving roller 21 and the driven roller 22 each have a plurality of layers of elastic members 212, 222). ). In addition, an aspect in which the driven roller 22 has a plurality of layers of elastic members 222 and the drive roller 21 has one layer of elastic members 212 may also be employed. In addition, it is also possible to adopt an aspect in which both the driving roller 21 and the driven roller 22 each have one layer of elastic members 212 and 222 .

In addition, in this embodiment, the case where the nip roll 2 is arranged in the drawing bath L4 of the drawing treatment tank 14 is described, but the present invention is not limited thereto, and may be arranged in any treatment bath L of any treatment tank 1 . For example, as mentioned above, the stretching treatment of the original sheet film F0 can also be performed in the swelling treatment bath L1 of the swelling treatment tank 11, the dyeing treatment bath L2 of the dyeing treatment tank 12, or the cross-linking treatment bath L3 of the cross-linking treatment tank 13. Therefore, in this The nip roll 2 of this embodiment may also be arranged in the processing baths L when the stretching treatment is performed in the processing baths L. Thereby, the elongation cracking of the original film F0 in each processing bath L can be suppressed.

1: Processing tank 2, 2a, 2b: nip roll 3: Oven 11: Swelling treatment tank 12: dyeing tank 13: Cross-linking treatment tank 14: Extended treatment tank 15: Cleaning the treatment tank 21: Drive roller 22: driven roller F0: original plate film F1: Polarizer FR: release roller GR: guide roller L: treatment bath L1: swelling treatment bath L2: dyeing treatment bath L3: Cross-linking treatment bath L4: Extended treatment bath L5: Cleansing treatment bath 100: Manufacturing device 211,221: core material 211a, 221a: shaft part 211b, 221b: tubular part 212, 212a, 212b, 212c, 222: elastic members NR: nip roll

FIG. 1 is a diagram schematically showing a schematic configuration of a polarizer manufacturing apparatus according to an embodiment of the present invention. Fig. 2 is a diagram schematically showing a schematic configuration of a drive roller according to an embodiment of the present invention. Fig. 3 is a diagram schematically showing a schematic configuration of a driven roller according to an embodiment of the present invention.

1: Processing tank

2, 2a, 2b: nip roll

3: Oven

11: Swelling treatment tank

12: dyeing tank

13: Cross-linking treatment tank

14: Extended treatment tank

15: Cleaning the treatment tank

21: Drive roller

22: driven roller

F0: original plate film

F1: Polarizer

FR: release roller

GR: guide roller

L: treatment bath

L1: swelling treatment bath

L2: dyeing treatment bath

L3: Cross-linking treatment bath

L4: Extended treatment bath

L5: Cleansing treatment bath

100: Manufacturing device

211a: Shaft

NR: nip roll

Claims (8)

A method for manufacturing a polarizer, comprising arranging nip rollers in a treatment bath, and while conveying an original film with the nip rollers, processing the original film in the treatment bath, thereby manufacturing a polarizer; The above-mentioned nip roller is composed of a driving roller and a driven roller, and the driven roller is for conveying the aforementioned original film between the driven roller and the aforementioned driving roller; The surface hardness of the aforementioned drive roller is different from the surface hardness of the aforementioned driven roller. The method of manufacturing a polarizer according to claim 1, wherein the nip roller is arranged such that a part of the driving roller is located above the liquid level of the treatment bath, and the driven roller is immersed in the treatment bath; The surface hardness of the aforementioned drive roller is lower than the surface hardness of the aforementioned driven roller. The method of manufacturing a polarizer according to claim 1 or 2, wherein the surface hardness of the roller with a lower surface hardness among the aforementioned driving roller and the aforementioned driven roller is less than 50 on the Shore A hardness scale, or less than 80 on the Asker C hardness scale , The surface hardness of the roller with higher surface hardness is above 50 in Shore A hardness. The method of manufacturing a polarizer according to claim 1 or 2, wherein the aforementioned driving roller and/or the aforementioned driven roller have a core material and multiple layers of elastic members wound on the aforementioned core material; The surface hardness of the elastic member of the inner layer among the plurality of elastic members is higher than the surface hardness of the elastic member of the outer layer. The method of manufacturing a polarizer according to claim 4, wherein the plurality of layers of elastic members is a three-layer elastic member. The method of manufacturing a polarizer according to claim 1 or 2, wherein among the driving roller and the driven roller, the outer diameter of the roller with lower surface hardness is larger than the outer diameter of the roller with higher surface hardness. The method of manufacturing a polarizer according to claim 1 or 2, wherein the treatment bath is a treatment bath for stretching the original plate film. A device for manufacturing a polarizer, comprising a treatment tank for storing a treatment bath and nip rollers arranged in the treatment bath; the device performs treatment on the original film in the treatment bath while conveying the original film with the nip rollers , to make polarizers; The above-mentioned nip roller is composed of a driving roller and a driven roller, and the driven roller is for conveying the aforementioned original film between the driven roller and the aforementioned driving roller; The surface hardness of the aforementioned drive roller is different from the surface hardness of the aforementioned driven roller.

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