JP2009014873A - Method for producing polarizer, polarizer, polarizing plate, image display device, liquid crystal panel and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a polarizer capable of further improving optical properties and the uniformity thereof. <P>SOLUTION: The method for producing a polarizer comprises: a swelling process (A) for swelling a hydrophilic polymer film; a stretching process (B); and a dyeing process (C). The swelling process (A) includes a non-stretching swelling stage (A1) and a stretching swelling stage (A2), and they are performed prior to the dyeing process (C). The method may comprise a crosslinking process (D), a cleaning process (E) or the like. The non-stretching swelling process (A1), stretching swelling process (A2), dyeing process (C), crosslinking process (D) and cleaning process (E) are performed in this order, and the stretching process (B) is performed simultaneously with the dyeing process (C) or crosslinking process (D). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a polarizer, a polarizer, a polarizing plate, an image display device, a liquid crystal panel, and a liquid crystal display device.

  The polarizing plate is used in various image display devices, and is an essential constituent member particularly in a liquid crystal display device (LCD). In general, the polarizing plate is configured by disposing a protective layer on at least one surface of a polarizer.

  The polarizer is manufactured by a manufacturing method including a stretching process of stretching a hydrophilic film such as a polyvinyl alcohol (PVA) film, and a dyeing process of dyeing the hydrophilic film with a dichroic substance. However, the manufactured polarizer may have non-uniform optical characteristics due to uneven phase difference, uneven content of dichroic material, and the like. For this reason, it has been proposed to use a hydrophilic film having a uniform thickness as much as possible, but it is not sufficient as a solution to the above problem.

  Moreover, in the manufacturing method of a polarizer, using the swelling process which swells the said hydrophilic film with water, aqueous solution, etc. prior to the said extending process and dyeing | staining process is performed (patent document 1 and 2 grade | etc.,). The purpose of performing the swelling step is, for example, removal of foreign matter on the surface of the hydrophilic film, removal of a plasticizer in the hydrophilic film, imparting easy dyeability in the dyeing step, and plasticizing of the hydrophilic film. However, in the swelling process, swelling unevenness generated in the initial stage of the swelling process may remain in the subsequent process. The remaining swelling unevenness becomes a factor of reducing the uniformity of the optical characteristics of the manufactured polarizer.

In order to suppress the swelling unevenness, the hydrophilic film swelling process is divided into a plurality of stages, immersed in a low-temperature bath solution in the initial stage, and gradually immersed in a high-temperature bath liquid as the subsequent stage is performed. (Patent Document 2). According to this method, the progress of swelling in the initial stage is alleviated, swelling unevenness is suppressed, and the hydrophilic film can be sufficiently swollen in the subsequent stage. For this reason, it is possible to obtain a polarizer excellent in the uniformity of optical characteristics. However, in this method, since it is necessary to set a plurality of bath liquids at different temperatures in the swelling step, there are problems of temperature management and cost of the bath liquid.
JP 2005-227648 A JP 2006-267153 A

  If the swelling amount of the hydrophilic film is small in the swelling step in the method for producing a polarizer, the dyeability and stretchability are not sufficiently improved, and the optical properties of the polarizer may be lowered. In order to increase the swelling amount, for example, there are methods of increasing the contact time of the hydrophilic film with the swelling liquid or raising the temperature of the swelling liquid. However, even if the hydrophilic film is swollen in this manner, there is a problem of swelling unevenness as described above. In the swelling step, there are a method of swelling the hydrophilic film while stretching, and a method of swelling the hydrophilic film without stretching, but both methods solve the problem of the swelling unevenness. Is not enough. Further, the method described in Patent Document 2 has problems of labor and cost as described above.

  Accordingly, an object of the present invention is to provide a method of manufacturing a polarizer that can be easily performed and that can further improve the optical characteristics and uniformity of optical characteristics of the manufactured polarizer. .

In order to achieve the above object, the method for producing a polarizer of the present invention comprises:
(A) a swelling step for swelling the hydrophilic polymer film,
(B) Stretching step for stretching the hydrophilic polymer film, and (C) Dyeing step for dyeing the hydrophilic polymer film with a dichroic substance,
A method for producing a polarizer, wherein the swelling step (A) is performed prior to the dyeing step (C),
The swelling step (A)
(A1) a non-stretching swelling process for swelling the hydrophilic polymer film without stretching, and (A2) a stretching swelling process for swelling the hydrophilic polymer film while stretching,
It is characterized by including.

  The polarizer of the present invention is a polarizer produced by the production method of the present invention.

  The polarizing plate of the present invention is a polarizing plate in which a protective layer is disposed on at least one surface of the polarizer, and the polarizer is the polarizer of the present invention.

  The image display device of the present invention is an image display device including the polarizer of the present invention or the polarizing plate of the present invention.

  The liquid crystal panel of the present invention includes a liquid crystal cell and a polarizing plate, and the polarizing plate is disposed on one side or both sides of the liquid crystal cell, and the polarizing plate is the polarizing plate of the present invention.

  The liquid crystal display device of the present invention is a liquid crystal display device including the polarizer of the present invention, the polarizing plate of the present invention, or the liquid crystal panel of the present invention.

  The present inventors have made a series of studies in order to achieve the above object. Polarized light produced by using both a non-stretching swelling process in which the hydrophilic polymer film is swollen without stretching and a stretching swelling process in which the hydrophilic polymer film is swollen while stretching in the course of the research. It has been found that the optical properties and uniformity of optical properties of the child are further improved. Although the detailed mechanism is unknown, for example, the hydrophilic polymer film swells sufficiently when the both steps are used together rather than using the non-stretching swelling step or the stretching swelling step alone, and the hydrophilic polymer film. It is presumed that with the improvement of the stretchability, the orientation is improved and the dyeability and the like are further improved. In the method for producing a polarizer of the present invention, in the non-stretching swelling step (A1) and the stretching / swelling step (A2), it is necessary to manage the temperature of the liquid brought into contact with the hydrophilic polymer film separately and strictly. Absent. For this reason, the manufacturing method of the polarizer of this invention can be performed simply, and can manufacture the polarizer excellent in the optical characteristic and the uniformity of an optical characteristic. Since the polarizer and polarizing plate of the present invention are excellent in optical characteristics and uniformity of optical characteristics, they can be suitably used for liquid crystal panels, liquid crystal display devices, and other various image displays.

As described above, the method for producing a polarizer of the present invention includes a swelling step (A), a stretching step (B), and a dyeing step (C), and the swelling step (A) precedes the dyeing step (C). The swelling step (A) includes a non-stretching swelling step (A1) and a stretching swelling step (A2). Other than this, the method for producing the polarizer of the present invention is not particularly limited.
(D) a crosslinking step of crosslinking the hydrophilic polymer film dyed by the dyeing step (C),
It is preferable that it is further included. Moreover, the manufacturing method of the polarizer of this invention is, for example,
(E) a washing step for washing the hydrophilic polymer film;
It is preferable that it is further included.

  In the present invention, the hydrophilic polymer film is preferably a polyvinyl alcohol film, and the dichroic substance is preferably iodine.

  In the present invention, for example, when the hydrophilic polymer film is a belt-like film and the steps included in the method for producing a polarizer of the present invention are continuously performed while continuously feeding the film, a polarizer is obtained. It is preferable from the viewpoint of production efficiency. Such a method can be performed by, for example, a so-called Roll to Roll method or a method based thereon. However, the manufacturing method of the polarizer of the present invention is not limited to this, and may be performed by a discontinuous method such as so-called batch processing.

  In the method for producing a polarizer of the present invention, for example, at least one of the steps (A1), (A2) and (B) to (E) is performed by immersing the hydrophilic polymer film in a bath solution. However, other methods may be used. For example, in the method for producing a polarizer of the present invention, at least one of the steps (A1), (A2) and (B) to (E) is performed on at least one surface of the hydrophilic polymer film in a gas phase. Can be carried out by bringing the solution into contact with the liquid. The contact between the liquid and the surface is preferably performed, for example, by spraying the liquid onto at least one surface of the hydrophilic polymer film. According to such a method, it is easy to cope with the production of a large polarizer. Examples of the liquid used in the present invention include a swelling liquid, a dyeing liquid, a crosslinking liquid, and a cleaning liquid described later.

  Next, an example is given and the manufacturing method of the polarizer of this invention is demonstrated below. The production method of the present invention uses a hydrophilic polymer film as a material, for example, a series of steps such as a swelling step (A), a stretching step (B), a dyeing step (C), a crosslinking step (D), and a washing step (E). The swelling step (A) includes a non-stretching swelling step (A1) and a stretching swelling step (A2).

[1] Hydrophilic polymer film The hydrophilic polymer film is not particularly limited, and a conventionally known film can be used. Specifically, for example, hydrophilic polymers such as polyvinyl alcohol (PVA) film, partially formalized PVA film, polyethylene terephthalate (PET) film, ethylene / vinyl acetate copolymer film, and partially saponified films thereof. A film etc. are mentioned. In addition to these, polyene oriented films such as PVA dehydrated products and polyvinyl chloride dehydrochlorinated products, stretched and oriented polyvinylene films, and the like can also be used. Among these, since it is excellent in the dyeability by the iodine which is a dichroic substance mentioned later, a PVA-type polymer film is preferable.

  As a raw material polymer of the PVA polymer film, for example, saponified after polymerizing vinyl acetate, or a small amount of a copolymerizable monomer such as unsaturated carboxylic acid or unsaturated sulfonic acid with respect to vinyl acetate. Examples thereof include a copolymerized polymer. The polymerization degree of the PVA polymer is not particularly limited, but is preferably in the range of 500 to 10,000, more preferably 1000 to 6000, from the viewpoint of solubility in water. The saponification degree is preferably 75 mol% or more, and more preferably 98 to 100 mol%.

  The size of the hydrophilic polymer film (for example, PVA film) is not particularly limited, but the thickness is, for example, in the range of 15 to 110 μm, preferably in the range of 38 to 110 μm, more preferably, It is 50-100 micrometers, More preferably, it is 60-80 micrometers. When the production method of the present invention is carried out in a continuous process such as a Roll to Roll method, the hydrophilic polymer film (for example, a PVA film) is preferably in the form of a raw film wound around a roll. A process is performed in each process, conveying a film. Moreover, when the manufacturing method of this invention is implemented by batch processing, the hydrophilic polymer film (for example, PVA-type film) cut into the predetermined magnitude | size is used.

[2] Swelling step (A)
Prior to the dyeing step (C), the swelling step (A) is performed. Thereby, the dyeability in the said dyeing | staining process (C) of the said hydrophilic polymer film can further be improved. Moreover, the orientation in the said extending process (B) of the said hydrophilic polymer film can also be improved further by performing the said swelling process (A) prior to the said extending process (B). The swelling step (A) includes the non-stretching swelling step (A1) and the stretching / swelling step (A2). Either the unstretched swelling step (A1) or the stretched swelling step (A2) may be performed first. The non-stretching swelling step (A1) is preferably performed prior to the stretching / swelling step (A2) from the viewpoint of further improving the orientation during stretching of the hydrophilic polymer film. Moreover, although the said non-stretching swelling process (A1) and the said stretching swelling process (A2) may each be performed once, you may perform it in multiple times. For example, after performing the non-stretching swelling step (A1) a plurality of times, the stretching / swelling step (A2) may be performed a plurality of times, or the non-stretching swelling step (A1) and the stretching / swelling step (A2) may be performed. You may carry out alternately. Hereinafter, each process of the said non-stretching swelling process (A1) and the said stretching swelling process (A2) is demonstrated.

[2-1] Non-stretching swelling process (A1)
The hydrophilic polymer film is swollen by contacting with a swelling liquid. At this time, the hydrophilic polymer film is not stretched. As said swelling liquid, water, glycerol aqueous solution, etc. can be used, for example.

  The method of bringing the hydrophilic polymer film into contact with the swelling liquid is not particularly limited, and for example, a method of immersing in a swelling bath containing the swelling liquid may be used. The temperature of the swelling bath (swelling liquid) is not particularly limited, but is, for example, in the range of 20 to 45 ° C, preferably in the range of 25 to 40 ° C, and more preferably in the range of 27 to 37 ° C. The immersion time in the swelling bath (contact time with the swelling liquid) is not particularly limited, but is, for example, in the range of 10 to 60 seconds, preferably in the range of 20 to 60 seconds, more preferably It is in the range of 30-60 seconds. The water content (water content) of the hydrophilic polymer film after the treatment by the non-stretching swelling step (A1) is not particularly limited, but is, for example, 10 to 35% by mass, preferably 20 to 35% by mass. Yes, more preferably 30 to 35% by mass.

  The method of bringing the hydrophilic polymer film into contact with the swelling liquid may be, for example, a method of spraying the swelling liquid on at least one surface of the hydrophilic polymer film in a gas phase. Any appropriate spraying device can be used as means for spraying the swelling liquid onto the hydrophilic polymer film. Examples of the spraying device include a product name “MK series” manufactured by Fuso Seiki Co., Ltd., a product name “T-AFPV” manufactured by DeVILBISS, and a product name “56 series” manufactured by ACCUSPLAY. In the spraying device, the number of spray nozzles is, for example, in the range of 1 to 10, preferably in the range of 1 to 8, and more preferably in the range of 1 to 4. The hole diameter of the spray nozzle is, for example, in the range of 0.3 to 2 mm, preferably in the range of 0.5 to 1.5 mm, and more preferably in the range of 0.75 to 1 mm. The flow rate per one spray nozzle is, for example, in the range of 10 to 1200 mL / second, preferably in the range of 10 to 700 mL / second, and more preferably in the range of 50 to 400 mL / second. The atomizing air pressure is, for example, in the range of 0.03 to 3 MPa, preferably in the range of 0.1 to 1 MPa, and more preferably in the range of 0.2 to 0.5 MPa. The spray angle is, for example, in the range of 45 ° to 135 °, preferably in the range of 60 ° to 120 °, and more preferably in the range of 80 ° to 100 °.

  In spraying the liquid, the distance between the spray nozzle and the hydrophilic polymer film can be appropriately determined according to the spray pressure or the like, but a range of 15 cm or less is preferable. By setting the distance within the above range, the liquid can be reliably brought into contact with the hydrophilic polymer film without loss.

The amount of the swelling liquid sprayed onto the hydrophilic polymer film is not particularly limited, but is preferably in the range of 0.06 to 0.19 mL / cm ² . The temperature of the swelling liquid and the spraying time of the swelling liquid (the contact time between the hydrophilic polymer film and the swelling liquid) are not particularly limited, but are the same as, for example, the case of immersing in the swelling bath.

  Moreover, you may perform the contact of the said swelling liquid by application | coating of the said swelling liquid to the said hydrophilic polymer film. The contact time of the liquid to the hydrophilic polymer film, the liquid temperature, and the like are not particularly limited, but are the same as, for example, when the liquid is sprayed. As means for applying the liquid to the hydrophilic polymer film, conventionally known means such as a roll coater, a die coater, a bar coater, a slide coater, and a curtain coater can be used. In the contact with the swelling liquid, spraying and application of the swelling liquid may be used in combination.

[2-2] Stretching and swelling step (A2)
The hydrophilic polymer film is swollen by contacting with a swelling liquid. At the same time, the hydrophilic polymer film is stretched. As described above, this step may be performed before or after the non-stretching swelling step (A1), but is preferably performed after the non-stretching swelling step (A1). As said swelling liquid, water, glycerol aqueous solution, etc. can be used, for example.

  The method of bringing the hydrophilic polymer film into contact with the swelling liquid is not particularly limited, and for example, a method of immersing in a swelling bath containing the swelling liquid may be used. The temperature of the swelling bath (swelling liquid) is not particularly limited, but is, for example, in the range of 20 to 45 ° C, preferably in the range of 25 to 40 ° C, and more preferably in the range of 27 to 37 ° C. The immersion time in the swelling bath (contact time with the swelling liquid) is not particularly limited, but is, for example, in the range of 10 to 60 seconds, preferably in the range of 20 to 60 seconds, more preferably It is in the range of 30-60 seconds. Although the water content (water content) of the hydrophilic polymer film after the treatment by the stretching and swelling step (A2) is not particularly limited, it is, for example, 10 to 35% by mass, preferably 20 to 35% by mass. More preferably, it is 30-35 mass%.

  The method of bringing the hydrophilic polymer film into contact with the swelling liquid may be, for example, a method in which the swelling liquid is sprayed or applied to at least one surface of the hydrophilic polymer film in the gas phase. May be. The liquid temperature of the swelling liquid, the contact time between the hydrophilic polymer film and the swelling liquid are not particularly limited, but are the same as, for example, the case where the swelling liquid is immersed in the swelling bath. The spraying means, the application means and the like are not particularly limited, but are the same as, for example, the non-stretching swelling step (A1).

  Stretching is preferably uniaxial stretching in the longitudinal direction (MD) of the hydrophilic polymer film from the viewpoint of being suitable for continuous treatment such as the Roll to Roll method, but is not limited thereto. It may be stretched. As a means for uniaxially stretching the hydrophilic polymer film, any suitable stretching machine such as a roll stretching machine, a tenter stretching machine, and a hand stretching machine can be used. In particular, the stretching treatment in the width direction of the hydrophilic polymer film can be performed using, for example, a conventionally known tenter stretching machine. Further, according to uniaxial stretching, the absorption axis of the polarizer can be generated in the stretching direction, but biaxial stretching may be used as long as the absorption axis can be appropriately generated. The draw ratio in this step, that is, the dimensional ratio in the drawing direction between the untreated hydrophilic polymer film and the hydrophilic polymer film after drawing is not particularly limited. In the case of longitudinal direction (MD) uniaxial stretching, the stretching ratio is, for example, in the range of 1.5 to 5 times, preferably in the range of 1.8 to 4 times, and more preferably in the range of 2 to 3 times. Range. In the case of uniaxial stretching in the width direction, the stretching ratio is, for example, in the range of 1.5 to 5 times, preferably in the range of 1.8 to 4 times, and more preferably in the range of 2 to 3 times. is there. In the present invention, the term “untreated” for the hydrophilic polymer film refers to a state (raw fabric) in which no treatment is performed including a stretching treatment and a swelling treatment.

  As described above, the method for producing a polarizer of the present invention does not need to strictly control the temperature of the swelling liquid separately in the non-stretching swelling step (A1) and the stretching swelling step (A2). It can be carried out. The temperature of the swelling liquid is not particularly limited as described above. For example, in both the non-stretching swelling process (A1) and the stretching swelling process (A2), the temperature of the swelling liquid is set to a temperature equal to room temperature. You can also

[3] Stretching step (B)
The stretching step (B) may be performed independently from the other steps, but it is preferable to perform the stretching step simultaneously with at least one of the other steps from the viewpoint of production efficiency, optical characteristics of the polarizer, and the like. For example, the stretching step (B) may be performed by stretching the hydrophilic polymer film at the same time in at least one of the dyeing step (C) and the crosslinking step (D). Further, for example, the stretching step (B) may be performed by stretching in the stretching / swelling step (A2), and the hydrophilic polymer film may not be stretched otherwise. Accordingly, the stretching step (B) may be performed in a liquid such as a swelling liquid, a dyeing liquid, or a cross-linking liquid as necessary, or may be performed in a gas phase. A suitable draw ratio is not particularly limited, and can be appropriately set according to the situation in which the drawing step (B) is performed. The stretching means is not particularly limited, and examples thereof include those described in the stretching and swelling step (A2). Although the stretching direction is not particularly limited, for example, as described in the stretching and swelling step (A2), uniaxial stretching in the longitudinal direction, uniaxial stretching in the width direction, or biaxial stretching may be used. Furthermore, the frequency | count of performing the said extending process (B) in particular is not restrict | limited, One time may be sufficient and multiple times may be sufficient.

[4] Dyeing process (C)
The hydrophilic polymer film swollen in the swelling step (A) is brought into contact with a staining solution containing a dichroic substance, and dyeing with the dichroic substance is performed. At this time, the hydrophilic polymer film may or may not be stretched at the same time.

  The dichroic substance is not particularly limited, but for example iodine is preferable. As the solvent, for example, water is preferable, and a small amount of an organic solvent compatible with water may be added. The iodine concentration in the staining solution is not particularly limited, and is, for example, 0.1 to 1.0 part by mass per 100 parts by mass of the solvent. Further, for example, in order to increase the dyeing efficiency, in the dyeing solution, potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, iodine Auxiliaries such as iodides such as calcium iodide, tin iodide and titanium iodide may be added. These auxiliaries may be used alone or in combination. The addition amount of the auxiliary agent is not particularly limited, but is, for example, 0.02 to 20 parts by mass, preferably 2 to 10 parts by mass per 100 parts by mass of the solvent. Further, for example, when iodine and potassium iodide are used in combination, the ratio (A: B (mass ratio)) of iodine (A) and potassium iodide (B) in the solution is, for example, 1: 5 to The range is 1: 100, preferably 1: 7 to 1:50, and more preferably 1:10 to 1:30.

  A method for bringing the hydrophilic polymer film into contact with the dyeing liquid is not particularly limited, and for example, a method of immersing in a dyeing bath containing the dyeing liquid may be used. The immersion time of the hydrophilic polymer film in the dyeing bath (contact time with the dyeing solution) is not particularly limited, but is, for example, in the range of 18 to 120 seconds, and preferably in the range of 18 to 90 seconds. More preferably, it is the range of 25 to 60 seconds. The temperature of the dye bath (dye solution) is not particularly limited, but is, for example, in the range of 5 to 42 ° C, preferably in the range of 10 to 35 ° C, and more preferably in the range of 12 to 30 ° C. It is a range. This temperature may be the same as the temperature of the swelling liquid in the swelling step (A). For example, if the temperature of the swelling liquid and the dyeing liquid are both equal to room temperature, the method for producing a polarizer of the present invention can be carried out simply and efficiently. Moreover, from the viewpoint of dyeing efficiency and the like, the temperature of the dyeing liquid may be set, for example, 3 to 15 ° C. lower than the temperature of the swelling liquid in the swelling step (A), and preferably 5 to 12 ° C. lower. Set, more preferably set lower by 8 to 10 ° C.

  The method of bringing the hydrophilic polymer film into contact with the dyeing solution may be, for example, a method of spraying or applying the dyeing solution to at least one surface of the hydrophilic polymer film in the gas phase. May be. The liquid temperature of the dyeing liquid, the contact time between the hydrophilic polymer film and the dyeing liquid, etc. are not particularly limited, but are the same as, for example, the case of immersing in the dyeing bath. The spraying means, the application means and the like are not particularly limited, but are the same as, for example, the non-stretching swelling step (A1).

  In the dyeing step (C), when stretching is performed at the same time, the stretching ratio is not particularly limited, but it is 2 to 6 times, for example, in a dimensional ratio with the untreated hydrophilic polymer film (raw fabric), preferably It is 2.5 to 5.5 times, more preferably 3 to 5 times. The stretching means is not particularly limited, and examples thereof include those described in the stretching and swelling step (A2). Although the stretching direction is not particularly limited, for example, as described in the stretching and swelling step (A2), uniaxial stretching in the longitudinal direction, uniaxial stretching in the width direction, or biaxial stretching may be used.

  In addition, in a prior art, a swelling process and a dyeing process may be performed simultaneously by swelling a hydrophilic polymer film using a dyeing liquid. However, in the present invention, the dyeing step (C) is separate from the non-stretching swelling step (A1) and the stretching swelling step (A2).

  Further, the number of times of performing the dyeing step (C) is not particularly limited, and may be one or more times. For example, you may use together the process which only dye | stains and does not extend | stretch, and the process which performs dyeing | staining and extending | stretching simultaneously.

[5] Crosslinking step (D)
The hydrophilic polymer film dyed in the dyeing step (C) is brought into contact with a cross-linking solution containing a cross-linking agent to carry out a cross-linking treatment. By this treatment, the dichroic material used for dyeing is further easily fixed in the polarizer. At this time, the hydrophilic polymer film may or may not be stretched at the same time.

  As the crosslinking agent, conventionally known substances can be used, and examples thereof include boron compounds such as boric acid, borax, glyoxal, and glutaraldehyde. These may be used alone or in combination of two or more. As the solution of the crosslinking bath, a solution in which the crosslinking agent is dissolved in a solvent can be used. As the solvent, for example, water can be used, but an organic solvent compatible with water may be further included.

  The concentration of the crosslinking agent in the solution is not particularly limited, but is preferably in the range of 0.1 to 10 parts by weight, more preferably 1.5 to 100 parts by weight with respect to 100 parts by weight of the solvent (for example, water). It is the range of 8 weight part, More preferably, it is the range of 2-6 weight part.

  In addition to the boric acid compound, for example, potassium iodide, lithium iodide, sodium iodide, zinc iodide, and iodide can be used for the cross-linking agent-containing solution in addition to the boric acid compound because uniform characteristics in the plane of the polarizer can be obtained. Auxiliaries such as iodides such as aluminum, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide and titanium iodide may be included. Among these, a combination of boric acid and potassium iodide is preferable. The content of the auxiliary agent in the solution is, for example, in the range of 0.05 to 15% by weight, and preferably in the range of 0.5 to 8% by weight.

  A method for bringing the hydrophilic polymer film into contact with the crosslinking liquid is not particularly limited, and for example, a method of immersing in a crosslinking bath containing the crosslinking liquid may be used. The immersion time of the hydrophilic polymer film in the crosslinking bath (contact time with the crosslinking liquid) is not particularly limited, but is, for example, 1 to 900 seconds, preferably 5 to 600 seconds, more Preferably, it is 12 to 120 seconds, and particularly preferably 18 to 60 seconds. The temperature of the crosslinking bath (crosslinking solution) is not particularly limited, but is, for example, in the range of 20 to 70 ° C, and preferably in the range of 40 to 60 ° C.

  The method of bringing the hydrophilic polymer film into contact with the crosslinking liquid may be, for example, a method in which the crosslinking liquid is sprayed or applied to at least one surface of the hydrophilic polymer film in the gas phase. May be. The liquid temperature of the cross-linking liquid, the contact time between the hydrophilic polymer film and the cross-linking liquid are not particularly limited, but are the same as, for example, the case of immersing in the cross-linking bath. The spraying means, the application means and the like are not particularly limited, but are the same as, for example, the non-stretching swelling step (A1).

  In the crosslinking step (D), when stretching is performed simultaneously, the stretching ratio is not particularly limited, but is a dimensional ratio in the stretching direction with respect to the untreated hydrophilic polymer film (raw fabric), for example, 3 to 8 times, preferably It is 3.5-7 times, More preferably, it is 4-6 times. The stretching means is not particularly limited, and examples thereof include those described in the stretching and swelling step (A2). Although the stretching direction is not particularly limited, for example, as described in the stretching and swelling step (A2), uniaxial stretching in the longitudinal direction, uniaxial stretching in the width direction, or biaxial stretching may be used.

  Moreover, the frequency | count in particular of performing a bridge | crosslinking process (D) is not restrict | limited, You may be once or several times. For example, you may use together the process of performing only bridge | crosslinking and not extending | stretching, and the process of performing bridge | crosslinking and extending | stretching simultaneously.

[6] Cleaning step (E)
The hydrophilic polymer film is treated by the dyeing step (C), preferably further treated by the crosslinking step (D), and then washed by contacting with a cleaning solution. By this treatment, for example, unnecessary dichroic substances and unnecessary substances such as a crosslinking agent can be removed. The cleaning liquid is not particularly limited, and may be water or an aqueous solution, for example. A small amount of a solvent compatible with water may be added. In the case of an aqueous solution, the solute is not particularly limited, and examples thereof include iodides such as potassium iodide. The addition amount of the solute is not particularly limited, but is, for example, 0.1 to 10 parts by mass with respect to 100 parts by mass of the solvent. Further, an auxiliary agent such as zinc sulfate or zinc chloride may be further added.

  A method for bringing the hydrophilic polymer film into contact with the cleaning liquid is not particularly limited, and for example, a method in which the hydrophilic polymer film is immersed in a cleaning bath containing the cleaning liquid may be used. The immersion time (contact time with the cleaning liquid) of the hydrophilic polymer film in the cleaning bath is not particularly limited, but is, for example, in the range of 1 to 60 seconds. The temperature of the cleaning bath (cleaning solution) is not particularly limited, but is, for example, 10 to 60 ° C, preferably 30 to 40 ° C.

  The method of bringing the hydrophilic polymer film into contact with the cleaning liquid may be, for example, a method in which the cleaning liquid is sprayed or applied to at least one surface of the hydrophilic polymer film in the gas phase. Also good. The temperature of the cleaning liquid, the contact time between the hydrophilic polymer film and the cleaning liquid, and the like are not particularly limited, but are the same as, for example, when immersed in the cleaning bath. The spraying means, the application means and the like are not particularly limited, but are the same as, for example, the non-stretching swelling step (A1).

  After the washing step (E), a drying step may be performed as necessary. The drying method is not particularly limited, and examples thereof include natural drying, air drying, and heat drying. The drying means is not particularly limited, and examples include drying means such as a drying furnace (oven) and a blower. The drying temperature is not particularly limited, but is, for example, 10 to 150 ° C, preferably 20 to 80 ° C, more preferably 25 to 80 ° C, still more preferably 30 to 75 ° C, and particularly preferably 35 to 70 ° C. is there.

  The swelling process (A), stretching process (B), dyeing process (C), crosslinking process (D), washing process (E), and drying process have been described above. These steps may be performed separately, but the steps that can be combined into one step may be performed collectively. For example, as described above, the stretching step (B) is preferably performed simultaneously with other steps. Further, for example, the drying step may be performed every time the steps (A) to (E) are completed.

  Through such a series of steps, a polarizer having excellent optical characteristics can be produced. The polarizer is usually used after being cut into a predetermined size.

  The stretch ratio of the produced polarizer is not particularly limited, but is preferably not too low from the viewpoint of obtaining a polarizer with a high degree of polarization, and is too high from the viewpoint of preventing defects such as breakage of the polarizer. Preferably not. In the case of uniaxial stretching in the longitudinal direction, the stretching ratio is, for example, 3 to 7 times, preferably 5 to 6.5, in the ratio of the length to the untreated hydrophilic polymer film (raw fabric). Is double. In the case of uniaxial stretching in the width direction, the stretching ratio is, for example, in the range of 2 to 12 times, preferably 3 to 10 times in the ratio of the width to the untreated hydrophilic polymer film (size ratio in the stretching direction). More preferably, it is a range of 4 to 8 times.

[7] Method for Producing Polarizer by Roll to Roll Method and Immersion of Hydrophilic Polymer Film in Bath Solution FIG. 1 shows an example of an apparatus for carrying out the method for producing a polarizer of the present invention. As shown in the figure, this apparatus includes a film delivery section 12, a non-stretched swelling tank 101, a stretched swelling tank 102, a dyeing tank 103, a crosslinking tank 104, a washing tank 105, and a polarizer winding section 13 arranged in series in this order. Has been configured. Drive rolls 121 and 121 ′ are disposed above the non-stretched swelling tank 101. Drive rolls 122 and 122 ′ are disposed above the stretching and swelling tank 102. Drive rolls 123 and 123 ′ are arranged above the dyeing tank 103. Drive rolls 124 and 124 ′ are arranged above the bridge tank 104. Drive rolls 125 and 125 ′ are disposed above the cleaning tank 105. The inside of each tank is filled with bath liquids 111-115. Specifically, the inside of the unstretched swelling tank 101 is filled with the swelling liquid 111, and guide rolls 131 and 131 ′ are disposed therein. The inside of the stretching and swelling tank 102 is filled with a swelling liquid 112, and guide rolls 132 and 132 ′ are disposed therein. The inside of the dyeing tank 103 is filled with a dyeing solution 113, and guide rolls 133 and 133 ′ are disposed therein. The inside of the crosslinking tank 104 is filled with the crosslinking liquid 114, and guide rolls 134 and 134 ′ are disposed therein. The inside of the cleaning tank 105 is filled with the cleaning liquid 115, and guide rolls 135 and 135 ′ are disposed therein. The bath liquids 111 to 115 are not particularly limited, but are, for example, as described above. A belt-like (long) hydrophilic polymer film 11 is wound around the film delivery unit 12 in a roll shape. The polarizer take-up unit 13 can take up the manufactured polarizer 11 ′. Each of the drive rolls 121 to 125 ′ is configured as a pair. A hydrophilic polymer film 11 (polarizer 11 ′) is sandwiched between the two rolls (rollers), and the hydrophilic polymer film 11 is continuously fed out from the film delivery unit 12 by the driving force of the rolls (rollers). Can be transported. In FIG. 1, when the hydrophilic polymer film 11 is delivered from the film delivery unit 12, the drive roll 121, the guide roll 131, the guide roll 131 ′, the drive roll 121 ′, the drive roll 122, the guide roll 132, and the guide roll 132. ', Driving roll 122', driving roll 123, guide roll 133, guide roll 133 ', driving roll 123', driving roll 124, guide roll 134, guide roll 134 ', driving roll 124', driving roll 125, guide roll 135 The guide roll 135 ′ and the drive roll 125 ′ are passed in this order, and are arranged so as to become the polarizer 11 ′ and to be wound around the polarizer winding unit 13. The driving rolls 121 to 125 ′ can individually adjust the rotation speed. By adjusting the rotation speed, an appropriate portion of the hydrophilic polymer film 11 can be applied with an appropriate tension, or no tension can be applied.

  The method for producing a polarizer of the present invention using the apparatus of FIG. 1 is performed as follows, for example. That is, first, the drive rolls 121 to 125 ′ are driven, and the hydrophilic polymer film 11 is continuously sent out from the film sending unit 12 and conveyed. Next, when the hydrophilic polymer film 11 passes through the guide rolls 131 and 131 ′, the non-stretching swelling step (A 1) is performed by immersing it in the swelling liquid 111 inside the non-stretching swelling tank 101. At this time, the hydrophilic polymer film 11 is not tensioned and stretched by adjusting the rotational speed of the drive roll. Next, when the hydrophilic polymer film 11 passes through the guide rolls 132 and 132 ′, the stretching and swelling step (A 2) is performed by immersing in the swelling liquid 112 inside the stretching and swelling tank 102. At this time, by adjusting the rotational speed of the drive roll, tension is applied to the hydrophilic polymer film 11, and uniaxial stretching is performed in the transport direction, that is, the longitudinal direction (MD). This stretching may be used as the stretching step (B), or may be performed as appropriate at the same time as the following steps to form the stretching step (B). Next, when the hydrophilic polymer film 11 passes through the guide rolls 133 and 133 ′, the dyeing step (C) is performed by immersing the dye in the dyeing solution 113 inside the dyeing tank 103. At this time, by adjusting the rotational speed of the drive roll, tension may be applied to the hydrophilic polymer film 11, and uniaxial stretching may be performed in the transport direction, that is, the longitudinal direction (MD), or stretching may not be performed. . Further, when the hydrophilic polymer film 11 passes through the guide rolls 134 and 134 ′, the crosslinking step (D) is performed by immersing in the crosslinking liquid 114 inside the crosslinking tank 104. At this time, by adjusting the rotational speed of the drive roll, tension may be applied to the hydrophilic polymer film 11, and uniaxial stretching may be performed in the transport direction, that is, the longitudinal direction (MD), or stretching may not be performed. . Further, when the hydrophilic polymer film 11 passes through the guide rolls 135 and 135 ′, the cleaning step (E) is performed by immersing it in the cleaning liquid 115 inside the cleaning tank 105. Then, the manufactured polarizer 11 ′ is wound up by the polarizer winding unit 13. Further, for example, in the apparatus of FIG. 1, drying means (not shown) such as a drying furnace (oven) and a blower are provided between the drive roll 125 ′ and the polarizer winding unit 13, thereby A drying process may be performed prior to the winding process.

  Thus, the manufacturing method of the polarizer using the apparatus of FIG. 1 can be implemented. The conditions in each step, for example, the temperature of the bath liquids 111 to 115, the immersion time, the draw ratio, etc. are not particularly limited, but are as described above, for example. Moreover, the manufacturing method of the polarizer of this invention is not limited to this, For example, as above-mentioned, you may use the system etc. which spray a batch process or each liquid on a hydrophilic polymer film.

[8] Polarizer The polarizer of the present invention can be produced by the method for producing a polarizer of the present invention, so that excellent optical properties and uniformity of optical properties can be obtained. You may manufacture by the method. The thickness is not particularly limited, but is, for example, 5 to 80 μm.

[9] Polarizing plate The polarizer of the present invention can be used as the polarizing plate of the present invention by disposing a protective layer on at least one surface thereof. The protective layer is preferably transparent, for example. Such a transparent protective layer can be formed, for example, as a coating layer of a polymer or as a laminate layer of a film. As the transparent polymer or film material for forming the transparent protective layer, an appropriate transparent material can be used, but a material excellent in optical transparency, mechanical strength, thermal stability, moisture barrier property and the like is preferable.

  Examples of the material for forming the transparent protective layer include polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as cellulose diacetate and triacetyl cellulose (TAC), acrylic polymers such as polymethyl methacrylate, Examples thereof include styrene polymers such as polystyrene and acrylonitrile / styrene copolymer (AS resin), and polycarbonate polymers. Polyethylene, polypropylene, polyolefin having cyclo or norbornene structure, polyolefin polymer such as ethylene / propylene copolymer, vinyl chloride polymer, amide polymer such as nylon and aromatic polyamide, imide polymer, sulfone polymer , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or these A mixture of polymers can also be exemplified as a material for forming the transparent protective layer. Furthermore, the transparent protective layer can be formed as a cured layer of thermosetting or ultraviolet curable resin such as acrylic, urethane, acrylurethane, epoxy, or silicone.

  In addition, when forming a transparent protective layer on both surfaces of a polarizer, each transparent protective layer may be formed from the same material, and can also be formed from a different material. The thickness of the transparent protective layer is not particularly limited, but is, for example, 500 μm or less, preferably 1 to 300 μm, more preferably 5 to 200 μm. Further, the surface of the transparent protective layer that does not come into contact with the polarizer is subjected to, for example, saponification treatment with alkali, plasma treatment, glow discharge treatment, corona discharge treatment, high frequency treatment, electron beam treatment, etc. Hard coat layer for preventing sticking, antireflection layer for preventing reflection of external light on the polarizer surface, anti-sticking layer for preventing adhesion to adjacent layers, diffused light transmitted through the polarizer It is also possible to provide a diffusion layer for expanding the viewing angle, an antiglare layer provided with a fine concavo-convex structure for the purpose of preventing reflection of external light on the surface of the polarizer, and the like.

  As the transparent protective layer, a cellulose polymer such as triacetyl cellulose is preferably used from the viewpoints of polarization characteristics and durability, and it is particularly preferable to attach a triacetyl cellulose film to a polarizer. For bonding the polarizer and the transparent protective layer (transparent protective film), for example, a polyvinyl alcohol (PVA) resin and a crosslinking agent can be used as an adhesive. As the PVA-based resin, for example, an unsubstituted PVA resin or a PVA resin having a highly reactive functional group is preferable. In particular, a PVA resin having a highly reactive functional group (for example, a polyvinyl alcohol resin modified with an acetoacetyl group) is preferable from the viewpoint of improving the durability of the polarizing plate.

  Examples of the crosslinking agent include (1) alkylene diamines having 2 alkylene groups and two amino groups such as ethylene diamine, triethylene diamine and hexamethylene diamine (particularly hexamethylene diamine is preferable), (2) tolylene diisocyanate, Hydrogenated tolylene diisocyanate, trimethylolpropane-tolylene diisocyanate adduct, triphenylmethane triisocyanate, methylene bis (4-phenylmethane triisocyanate, isophorone diisocyanate, and isocyanates such as ketoxime block or phenol block, 3) Ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin di or triglycidyl ether, 1,6-hex Diol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, diglycidylamine and other epoxies, (4) monoaldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, (5) glyoxal, malondi Dialdehydes such as aldehyde, succindialdehyde, glutardialdehyde, maleidialdehyde, phthaldialdehyde (especially glyoxal is preferred), (6) alkylated methylol urea, alkylated methylol melamine, acetoguanamine, benzoguanamine and formaldehyde Amino-formaldehyde resins such as condensates (especially alkylated methylol melamine is preferred), (7) sodium, potassium, magnesium, Calcium, mention may be made of aluminum, iron, divalent metal or trivalent metal salts and oxides such as nickel.

[10] Polarizing plate including an retardation layer (elliptical polarizing plate)
For example, the polarizing plate of the present invention preferably further includes a retardation layer. For example, the protective layer has a retardation, and may also serve as the retardation layer. The protective layer and the retardation layer may be separate layers. The polarizing plate including the retardation layer is called, for example, an elliptical polarizing plate. Moreover, the polarizing plate of this invention can be arrange | positioned at the one side or both sides of a liquid crystal cell, for example, and can comprise the liquid crystal panel of this invention.

[11] Image display device, liquid crystal panel, liquid crystal display device The polarizer or polarizing plate of the present invention can be preferably used as a component of various image display devices such as a liquid crystal display device (LCD), ELD, PDP and the like. . For example, as described above, the liquid crystal panel of the present invention has a structure in which the polarizing plate of the present invention is disposed on one side or both sides of the liquid crystal cell. The LCD of the present invention includes the polarizer of the present invention, the polarizing plate of the present invention, Or it is the structure containing the liquid crystal panel of this invention. Further, the LCD of the present invention can have an appropriate structure according to the conventional type such as a transmissive type, a reflective type, or a transmissive / reflective type. The liquid crystal cell forming the LCD is arbitrary, and for example, a liquid crystal cell of an appropriate type such as an active matrix driving type typified by a thin film transistor type may be used. Moreover, when arrange | positioning the polarizing plate of this invention on both sides of a liquid crystal cell, the same structure may be sufficient and a different structure may be sufficient. Furthermore, when forming the LCD, for example, appropriate components such as a prism array sheet, a lens array sheet, a diffusion plate, and a backlight can be arranged in one or more layers at appropriate positions.

  Examples of the present invention will be described together with comparative examples. The present invention is not limited or restricted by the following examples and comparative examples.

(Example)
A polyvinyl alcohol (PVA) film (trade name: VF-PS, manufactured by Kuraray Co., Ltd.) having a width of 180 mm, a length of 50 mm, and a thickness of 75 μm was prepared. For this PVA film, the non-stretching swelling step (A1) once, the stretching swelling step (A2) once, the dyeing step (C) once, the crosslinking step (D) twice, the washing step (E) Were performed once in this order. The immersion time in the non-stretching swelling process (A1) and the stretching swelling process (A2) was 30 seconds each, and the stretching ratio in the stretching swelling process (A2) was 2.2 times. In the second crosslinking step (D), the stretching step (B) was performed by stretching the PVA film at the same time. After the washing step (E), the PVA film was dried in an oven at 60 ° C. for 4 minutes. In this way, the polarizer of this example was obtained. The steps (A1) to (E) were all performed in a bath. Stretching was performed in a bath using a hand stretching machine, and the stretching direction was uniaxial stretching in the PVA film length direction. Table 1 below shows specific conditions for each step. In Table 1 below, the draw ratio is a ratio between the length (50 mm) of the untreated PVA film and the length after each step, that is, a dimensional ratio in the drawing direction. In the first cross-linking step (D), the draw ratio increased from 3.3 times to 3.6 times. This is because the PVA film swells by immersion in the bath solution and the lengthwise dimension is increased. This is because of the increase.

(Comparative Example 1)
A polarizer was produced in the same manner as in Example except that the non-stretching swelling step (A1) was not performed.

(Comparative Example 2)
Except that the non-stretching swelling step (A1) is not performed, and that the dipping time in the stretching swelling step (A2) is 60 seconds by setting the stretching speed to 1/2 in the stretching swelling step (A2). A polarizer was produced in the same manner as in the example. The total immersion time in the swelling process of Comparative Example 2 was 60 seconds, the same as in the example.

(Evaluation of optical properties and uniformity of optical properties)
About the polarizer of an Example and a comparative example, the uniformity (variation) of the optical characteristic and the optical characteristic was evaluated as follows.

  First, as shown in FIG. 2, samples were cut out from the polarizers of Examples and Comparative Examples at five locations. In the same figure, 20 shows the polarizer of an Example or a comparative example, 1-5 shows the sample cut-out location from the polarizer 20, and a and b show the extending | stretching direction. As shown in the drawing, Samples 1 to 5 were cut out in five numbers in series along the extending direction of the polarizer 20 in the order of numbers, and the sample 3 was cut out from substantially the center of the polarizer 20. Each sample was a 30 mm × 30 mm square, and the distance (cutout interval) between adjacent samples was 30 mm. And the single-piece | unit transmittance | permeability and polarization degree of these samples in the measurement wavelength of 550 nm were measured using the ultraviolet visible spectrophotometer (The JASCO Corporation make, brand name V7100). The degree of polarization is a value calculated from the single transmittance, the parallel transmittance, and the direct transmittance. Further, this evaluation was tried five times for each of the examples and the comparative examples, and the evaluation was performed based on the obtained single transmittance and polarization degree data.

  The standard deviation of the single transmittance of 5 samples cut out every trial was calculated and used as an evaluation index of the single transmittance variation. Table 2 shows the evaluation results of the single transmittance variation in the polarizers of Examples and Comparative Examples.

  As shown in Table 2, the polarizers of the examples had a variation in single transmittance (standard deviation of single transmittance) in samples 1 to 5 of 0.226 at the maximum. On the other hand, in Comparative Example 1, the dispersion of the single transmittance in Samples 1 to 5 was 0.420 at the maximum, and in Comparative Example 2 was 0.353 at the maximum. From this, it can be seen that in the example, a polarizer having uniform optical characteristics as compared with the comparative example could be manufactured. Further, regarding the evaluation of the sample at the sample cutout position 3 in FIG. 2, the result of the single transmittance is shown in Table 3, the result of the polarization degree is shown in Table 4, and FIG. 3 shows the relationship between the polarization degree and the single transmittance (TP) Curve). In the figure, the horizontal axis represents the single transmittance (%), and the vertical axis represents the degree of polarization (%). As shown in the average values in Table 3, the Examples have higher average single transmittance values than the Comparative Examples. Further, as shown in the evaluation results of the degree of polarization in Table 4, the examples have a higher average degree of polarization and a very small standard deviation than the respective comparative examples. This is shown in FIG. 3 in which the plot of the polarizer of the example is shifted to the upper right than the polarizer of each comparative example. That is, according to the manufacturing method of the present invention, it was confirmed that the optical characteristics of the polarizer were improved and that a polarizer having uniform optical characteristics could be stably manufactured.

  As described above, according to the manufacturing method of the present invention, it is possible to further improve the optical characteristics of the manufactured polarizer and the uniformity of the optical characteristics. The polarizer of the present invention and the polarizing plate of the present invention using the same can be suitably used for liquid crystal panels, liquid crystal display devices, and other various image displays because of excellent optical characteristics and uniformity of optical characteristics. . The use is not limited, for example, OA equipment such as desktop personal computers, notebook personal computers, and copy machines, mobile phones, watches, digital cameras, personal digital assistants (PDAs), portable devices such as portable game machines, video cameras, televisions, Home electrical equipment such as microwave ovens, back monitors, car navigation system monitors, in-vehicle equipment such as car audio, display equipment such as information monitors for commercial stores, security equipment such as monitoring monitors, nursing monitors, medical care It can be applied to a wide range of fields such as nursing care and medical equipment such as monitors.

FIG. 1 is a diagram showing an example of an apparatus for carrying out the method for producing a polarizer of the present invention. FIG. 2 is a schematic diagram showing the measurement sample cutout of the polarizers of the example and the comparative example. FIG. 3 is a graph showing the relationship between the single transmittance and the degree of polarization in the polarizers of Examples and Comparative Examples.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Hydrophilic polymer film 11 'Polarizer 12 Film delivery part 13 Polarizer winding part 101 Unstretched swelling tank 102 Stretched swelling tank 103 Dyeing tank 104 Crosslinking tank 105 Washing tank 121-125' Drive roll 131-135 'Guide roll 20 Polarizers 1 to 5 Polarizer measurement sample cutout points a and b Stretching direction

Claims (15)

(A) a swelling step for swelling the hydrophilic polymer film,
(B) Stretching step for stretching the hydrophilic polymer film, and (C) Dyeing step for dyeing the hydrophilic polymer film with a dichroic substance,
A method for producing a polarizer, wherein the swelling step (A) is performed prior to the dyeing step (C),
The swelling step (A)
(A1) a non-stretching swelling process for swelling the hydrophilic polymer film without stretching, and (A2) a stretching swelling process for swelling the hydrophilic polymer film while stretching,
The manufacturing method of the polarizer characterized by including. The method for producing a polarizer according to claim 1, wherein the non-stretching swelling step (A1) is performed prior to the stretching and swelling step (A2). The method for producing a polarizer according to claim 1 or 2, wherein the swelling treatment time in the non-stretching swelling step (A1) is in the range of 10 to 60 seconds. (D) a crosslinking step of crosslinking the hydrophilic polymer film dyed by the dyeing step (C),
The method for producing a polarizer according to any one of claims 1 to 3, further comprising: The manufacturing method of the polarizer as described in any one of Claim 1 to 4 which performs the said extending process (B) simultaneously with at least 1 among other processes. The process (A1), (A2) and at least one of (B) to (D) is performed by bringing at least one surface of the hydrophilic polymer film into contact with a liquid in a gas phase. The method for producing a polarizer according to claim 5. The manufacturing method of the polarizer of Claim 6 which makes the said liquid and the said surface contact by spraying the said liquid on the at least one surface of the said hydrophilic polymer film. 8. The method according to claim 1, wherein at least one of the steps (A1), (A2), and (B) to (D) is performed by immersing the hydrophilic polymer film in a bath solution. Manufacturing method of the polarizer. The method for producing a polarizer according to any one of claims 1 to 8, wherein the hydrophilic polymer film is a polyvinyl alcohol film, and the dichroic substance is iodine. The polarizer manufactured by the manufacturing method as described in any one of Claim 1 to 9. The polarizing plate in which a protective layer is disposed on at least one surface of the polarizer, wherein the polarizer is the polarizer according to claim 10. Furthermore, the polarizing plate of Claim 11 containing a phase difference layer. An image display device comprising the polarizer according to claim 10 or the polarizing plate according to claim 11 or 12. 13. A liquid crystal panel comprising a liquid crystal cell and a polarizing plate, wherein the polarizing plate is disposed on one side or both sides of the liquid crystal cell, wherein the polarizing plate is the polarizing plate according to claim 11 or 12. A liquid crystal display device comprising the polarizer according to claim 10, the polarizing plate according to claim 11 or 12, or the liquid crystal panel according to claim 14.

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