KR20200016171A - Method of producing polarizer - Google Patents

Abstract

Provided is a method capable of manufacturing a high-quality polarizer even when a peripheral edge unit has a decolorizing portion. A manufacturing method of the present invention relates to a manufacturing method of a polarizer having a dyeing portion and a decolorizing portion formed on at least a part of the peripheral edge unit. The manufacturing method comprises the steps of: dyeing a resin film; laminating a part corresponding to the dyeing portion of the dyed resin film and a surface protective material on the peripheral edge unit of the resin film; performing decolorizing treatment for the resin film in a state where the surface protective material is laminated to form an intermediate decolorizing portion removing the surface protective material; and cutting a part in which the surface protective material of the peripheral edge portion of the resin film is laminated, while including a part of the intermediate decolorizing portion.

Description

Manufacturing method of polarizer {METHOD OF PRODUCING POLARIZER}

The present invention relates to a method for producing a polarizer. In more detail, it is related with the manufacturing method of the polarizer which has a dyeing part and the discoloration part formed in at least one part of the peripheral edge part.

Polarizing plates are used in various image display devices such as mobile phones and notebook personal computers (PCs). Recently, an image display device having a camera and various sensors has been developed. As a polarizer used for such an image display apparatus, the polarizer which partially discolored the part corresponding to a camera is proposed (patent document 1). In addition, there is a demand for an image display device having excellent design as well as function. Therefore, the polarizer which has a discoloration part not only in a part of polarizer but a peripheral part of a polarizer is calculated | required. However, when a discoloration part is formed also in the peripheral edge part, the quality, such as the external appearance of a polarizer, may fall in a manufacturing process. For this reason, there is a demand for a method capable of providing a high quality polarizer even when a discoloration portion is formed at the peripheral edge portion.

Japanese Laid-Open Patent Publication No. 2014-112238

This invention is made | formed in order to solve the said conventional subject, The main objective is to provide the method which can manufacture a high quality polarizer even if it has a bleaching part in a peripheral edge part.

This invention is a manufacturing method of the polarizer which has a dyeing part and the discoloration part formed in at least one part of the peripheral part. The manufacturing method of this invention performs a dyeing process to a resin film, laminate | stacks a surface protection material to the part corresponded to the dyeing part of the resin film processed, and the peripheral edge part of this resin film, and the surface protection material The surface protective material of the peripheral edge part of the resin film is laminated | stacked including decolorizing-processing a resin film in the laminated state, forming an intermediate decolorization part, removing the surface protection material, and a part of the intermediate decolorization part, Cutting the part that was present.

In one embodiment, the said discoloration part is formed in the whole peripheral edge part of a polarizer.

In one embodiment, the said decoloring process is performed by making a basic solution contact a dyeing process resin film.

In one embodiment, the contacting portion of the basic solution is further contacted with an acidic solution.

In one embodiment, the said cutting is implemented using a laser.

In one embodiment, the method further includes laminating a protective layer on the resin film.

In one embodiment, it further includes laminating another surface protective material to the said protective layer.

In one embodiment, the said discoloration process is performed in the state in which the said other surface protection material was laminated | stacked.

According to this invention, even when it has a discoloration part in a peripheral edge part, the method which can manufacture a high quality polarizer can be provided. This invention is a manufacturing method of the polarizer which has a dyeing part and the discoloration part formed in at least one part of the circumferential edge part. The manufacturing method of this invention performs a dyeing process to a resin film, laminate | stacks a surface protection material to the part corresponded to the dyeing part of the resin film processed, and the peripheral edge part of this resin film, and the surface protection material The surface protective material of the peripheral edge part of the resin film is laminated | stacked including decolorizing-processing a resin film in the laminated state, forming an intermediate decolorization part, removing the surface protection material, and a part of the intermediate decolorization part, Cutting the part that was present. In the manufacturing method of this invention, decolorization process is performed in the state which laminated | stacked the surface protection material also on the peripheral edge part of a resin film, and forms an intermediate decolorization part. Then, the part in which the surface protective material of the peripheral edge part of the resin film was laminated | stacked is cut | disconnected including a part of intermediate discoloration part so that a desired decolorization part may be carried out. The surface protective material is also laminated on the peripheral edge of the resin film, whereby the resin film is exposed between the surface protective material protecting the portion corresponding to the dyeing portion and the surface protective material laminated on the peripheral edge of the resin film (that is, decolorizing treatment). Part provided in) may be a recess. Therefore, for example, when performing a decolorization process by making a basic solution and a resin film contact, it becomes easy to make a basic solution contact only the part corresponding to the said recessed part of a resin film. Moreover, even when a basic solution contacts the outer side (for example, the side surface of a resin film) of the surface protection material laminated | stacked on the peripheral edge part of a resin film, this part is removed by a cutting process. Therefore, a basic solution penetrates from the exterior of a surface protection material, and as a result, it can prevent that a dyeing part discolors. By laminating | stacking a surface protective material, the quality of the discoloration part which the polarizer obtained can hold | maintain suitably.

1 is a schematic plan view of a polarizer manufactured by an embodiment of the present invention.
2 is a schematic plan view illustrating a state of the resin film in each step in one embodiment of the present invention.
It is a photograph which shows the state of the discoloration part of the polarizer (a) obtained by the Example and the polarizer (b) obtained by the comparative example.

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of this invention is described, this invention is not limited to these embodiment.

A. Manufacturing Method of Polarizer

This invention is a manufacturing method of the polarizer which has a dyeing part and the discoloration part formed in at least one part of the circumferential edge part. The manufacturing method of this invention performs a dyeing process to a resin film, laminate | stacks a surface protection material to the part corresponded to the dyeing part of the resin film processed, and the peripheral edge part of this resin film, and the surface protection material The surface protective material of the peripheral edge part of the resin film is laminated | stacked including decolorizing-processing a resin film in the laminated state, forming an intermediate decolorization part, removing the surface protection material, and a part of the intermediate decolorization part, Cutting the part that was present. In addition, in this specification, the peripheral edge part of a resin film includes the peripheral edge and vicinity of a resin film.

1 is a schematic plan view of a polarizer produced by one embodiment of the present invention. The polarizer 10 of the example of illustration has the dyeing | staining part 12 and the discoloration part 11 formed in the whole periphery edge part. Hereinafter, the manufacturing method of this invention is demonstrated in detail using this polarizer as a specific example. It is a schematic plan view explaining the state of the resin film of each process in one Embodiment of this invention. 2 (A) is a schematic plan view of the resin film before decolorization treatment. In the manufacturing method of this invention, a surface protective material is laminated | stacked on the part corresponded to the dyeing | staining part 12 of the polarizer 10 from which a resin film is obtained, and the peripheral edge part of a resin film. That is, the surface protection material 21 (henceforth an inner surface protection material) which protects the dyeing | staining part 12 of the polarizer 10, and the surface protection material 22 (henceforth an outer surface protection material) which protects the peripheral edge part of a resin film The decolorization process is performed about the resin film which laminated | stacked). Therefore, the decolorization process is performed only about the part 13 (henceforth an exposed part) exposed from the surface protection materials 21 and 22 of the resin film. The exposed portion 13 may be a recess having a depth corresponding to the thickness of the surface protective material. Therefore, even when decolorization is carried out by contact with the basic solution, the basic solution can be easily brought into contact with only the exposed portion 13. FIG. 2 (B) is a schematic plan view of the resin film of FIG. 2 (A) after decoloring treatment. By performing decolorization process only about the exposed part 13 of a resin film, the intermediate decolorization part 14 is formed in the part corresponding to the exposed part 13 of a resin film.

Next, the surface protective material is removed from the resin film in which the intermediate discoloration part 14 was formed. FIG. 2 (C) is a schematic plan view showing the state of the resin film of FIG. 2 (B) from which the surface protective material is removed. In FIG. 2 (B), the dyeing portion corresponding to the dyeing portion 12 of the polarizer 10 remains undiscolored in the portion where the inner surface protective material 21 is laminated. In addition, the outer dyeing part 15 remains without discoloring in the portion where the outer surface protective material 22 is laminated. Including the part of the intermediate discoloration part 14 of the resin film of FIG. 2C, the part in which the surface protective material of the resin film peripheral edge part was laminated | stacked (that is, the outer discoloration part 15) is cut | disconnected (the wave of an example of illustration) Line). As a result, the polarizer 10 which has the dyeing part 12 and the discoloration part 11 is obtained. By cutting off part of the intermediate decolorizing portion 14 (ie, cutting the inside of the intermediate decolorizing portion 14), for example, the outer surface of the surface protective material laminated to the peripheral edge of the resin film (eg, Even when a basic solution contacts the side surface of a resin film, this contact part can be removed from a desired polarizer. Therefore, a basic solution penetrates from the contact part of the side surface of a resin film, and as a result, it can prevent that a dyeing part discolors.

In one embodiment, the said resin film can be provided to each process in the state of a laminated body. As a laminated body, the laminated body of a resin film and a base material, and the laminated body of a resin film and a protective layer are mentioned, for example. In addition, this protective layer is not the layer laminated | stacked in order to protect a resin film in each process, but is a protective layer of the polarizer in the polarizing plate containing the polarizer finally obtained. This protective layer is laminated | stacked on a polarizer through arbitrary suitable adhesive layers or an adhesive bond layer. When a decoloring process is performed by the contact of a resin film and a basic solution, a resin film may swell by contact with a basic solution. When a resin film is provided to each process in the state of a laminated body, a problem may arise that a resin film peels from a base material or a protective layer by swelling and then shrinking after that. Moreover, the influence on the characteristic of an adhesive bond layer or an adhesive layer may also arise with a basic solution. According to the manufacturing method of this invention, it becomes possible to remove the part which generate | occur | produced such a problem by cutting process. Therefore, it becomes possible to manufacture a desired polarizer in various aspects.

A-1. Dyeing Treatment of Resin Film

The polarizer obtained by the manufacturing method of this invention has a dyeing part and the discoloration part formed in at least one part of the circumferential edge part. Typically, a polarizer can provide a polarizing function by performing various processes, such as dyeing process, crosslinking process, washing process, and drying process by dichroic substances, such as swelling process, extending | stretching process, and iodine, to a resin film. In the polarizer, the dyeing portion is a portion that exhibits a polarizing function. This dyeing section can be typically formed by dyeing a resin film. Therefore, it is preferable to perform these processes to a resin film in addition to a dyeing process. That is, it is preferable to perform the decoloring process mentioned later to the resin film which is a state which exhibits a polarizing function. In addition, when performing the process which gives a polarizing function to a resin film, the resin film may be formed on the base material. The laminated body of a base material and a resin layer can be obtained by the method of apply | coating the coating liquid containing the formation material of a resin film to a base material, the method of laminating | stacking a resin film on a base material, etc., for example.

Arbitrary suitable resin can be used as resin which forms a resin film. Preferably, polyvinyl alcohol-type resin (henceforth "PVA system resin") is used. As PVA system resin, polyvinyl alcohol and an ethylene-vinyl alcohol copolymer are mentioned, for example. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. An ethylene-vinyl alcohol copolymer is obtained by saponifying an ethylene-vinyl acetate copolymer. The saponification degree of PVA system resin is normally 85 mol% or more and less than 100 mol%, Preferably it is 95.0 mol%-99.95 mol%, More preferably, it is 99.0 mol%-99.93 mol%. Saponification degree can be calculated | required according to JISK6726-1994. By using PVA-type resin of such saponification degree, the polarizer excellent in durability can be obtained. If the degree of saponification is too high, there is a risk of gelation.

The average degree of polymerization of the PVA-based resin may be appropriately selected according to the purpose. The average degree of polymerization is usually 1000 to 10,000, preferably 1200 to 4500, and more preferably 1500 to 4300. In addition, an average degree of polymerization can be calculated | required according to JISK6726-1994.

As a dichroic substance, iodine, an organic dye, etc. are mentioned, for example. These may be used independently and may be used in combination of 2 or more type. Preferably iodine is used. This is because the decoloring part can be formed satisfactorily by contact with the basic solution described later.

A dyeing process is typically performed by making a dichroic substance adsorb | suck. As said adsorption method, the method of immersing a resin film in the dyeing solution containing a dichroic substance, the method of coating the said dyeing solution on a resin film, the method of spraying the said dyeing solution to a resin film, etc. are mentioned, for example. Can be. Preferably, it is a method of immersing a resin film in dyeing liquid. This is because the dichroic substance can be adsorbed well.

When using iodine as a dichroic substance, an aqueous solution of iodine is preferably used as the dyeing solution. The compounding quantity of iodine is 0.04 weight part-5.0 weight part preferably with respect to 100 weight part of water. In order to increase the solubility of iodine in water, it is preferable to blend the iodide in an aqueous solution of iodine. As iodide, potassium iodide is used preferably. The compounding quantity of iodide is 0.3 weight part-15 weight part preferably with respect to 100 weight part of water.

In the said extending | stretching process, a resin film is uniaxially stretched 3 to 7 times typically. In addition, the extending direction may correspond to the absorption axis direction of the polarizer obtained.

The thickness of the resin film (substantially, the polarizer obtained) to which the various processes for giving a polarization function were given can be set to arbitrary appropriate values. The thickness is typically 0.5 µm or more and 80 µm or less, preferably 30 µm or less, more preferably 25 µm or less, still more preferably 18 µm or less, particularly preferably 12 µm or less, particularly More preferably, it is less than 8 micrometers. The lower limit of the thickness is preferably 1 µm or more. The thin thickness can contribute to the thinning of the image display device. Moreover, the thinner the thickness, the better the discoloration part can be formed. For example, when contacting the basic solution mentioned later, a decolorization part can be formed in a short time. Moreover, the thickness of the part which contacted basic solution may become thinner than another part. When the thickness is thin, the difference between the thickness of the portion brought into contact with the basic solution and the other portion can be reduced.

A-2. Lamination of Surface Protective Materials

Next, a surface protective material is laminated | stacked on the surface of the resin film in which the process of said A-1 was performed. By laminating | stacking a surface protection material, it can prevent that the polarization function of the dyeing part of a resin film is impaired by subsequent processes, such as a decoloring process. The surface protective material is a portion corresponding to the dyed portion 12 of the polarizer 10 (surface protective material 21 in FIG. 2 (A)) and a peripheral edge portion of the resin film (surface protective material 22 in FIG. 2 (A)). Stacked).

In FIG. 2 (A), the surface protective material 21 which protects the dyed part 12 of the polarizer finally obtained, and the surface protective material 22 which protects the periphery of a resin film are laminated | stacked on the resin film. The part 13 exposed from the surface protection materials 21 and 22 is subjected to decolorization, so that the intermediate decolorizing portion 14 as shown in Fig. 2B is formed. As mentioned above, the outer surface protective material should just be laminated | stacked in the vicinity of the circumferential edge part of a resin film. In the example of illustration, although the outer surface protection material is protected by the outer surface protection material to the outer peripheral part of the resin film provided for a process, the discoloration part is further formed in the outer side of the part protected by the outer surface protection material (that is, the outer side of the outer surface protection material 22 further). You may be. Even when the discoloration part is further formed in the outer side, the discoloration part is removed by subsequent cutting process.

As described above, the inner surface protective material 21 is a size corresponding to the size of the dyed portion 12 of the polarizer 10. The outer surface protective material 22 can be designed to any suitable size (width). The width of the outer surface protective material 22 is 20 mm or more, for example, Preferably it is 25 mm or more. In terms of cost, for example, it is 30 mm or less.

As a surface protection material, a surface protection film is mentioned, for example. The surface protective film is used temporarily at the time of manufacture of a polarizer. Since a surface protection film is removed from a resin film at arbitrary appropriate timings, it is typically bonded to a resin film through an adhesive layer. As another specific example of the surface protective material, a photoresist etc. are mentioned. The inner surface protective material and the outer surface protective material may be the same surface protective material, or may be different surface protective materials.

The surface protective film may be formed of any suitable forming material. As a formation material of a surface protection film, For example, ester resins, such as polyethylene terephthalate resin, cycloolefin resins, such as norbornene-type resin, olefin resins, such as polypropylene, polyamide resin, and polycarbonate System resin, these copolymer resin, etc. are mentioned. Preferably, it is ester resin (especially polyethylene terephthalate resin).

The thickness of the surface protection film may be set to any suitable value. The thickness of a surface protection film is 30 micrometers-150 micrometers, for example.

As mentioned above, a surface protection film is laminated | stacked on a resin film through an adhesive layer. The pressure-sensitive adhesive layer is formed using any suitable composition. The composition for adhesive layer formation contains a resin component and arbitrary appropriate additives, for example. Arbitrary suitable resin can be used as base resin of an adhesive, For example, acrylic resin, silicone resin, rubber resin, urethane resin, etc. are mentioned.

Arbitrary suitable additives can be used as an additive. For example, crosslinking agents, coupling agents, tackifiers, surface lubricants, leveling agents, surfactants, antistatic agents, sliding properties, wetting properties, antioxidants, corrosion inhibitors, light stabilizers, ultraviolet light absorbers, polymerization inhibitors, crosslinking accelerators And powders such as crosslinking catalysts, inorganic or organic fillers, metal powders, pigments, particulates, thin powders and the like.

As mentioned above, in one Embodiment, the said resin film is provided to each process in the state which the protective layer was laminated | stacked. In this embodiment, it is preferable that a surface protective material (henceforth another surface protective material) is laminated | stacked also to this protective layer. By laminating other surface protective materials, the protective layer can be appropriately protected in the manufacturing process of the polarizer. Therefore, it becomes possible to perform the decoloring process mentioned later by immersion. Another surface protection material, the said inner surface protection material, and an outer surface protection material may be same or different.

A-3. Bleaching

The resin film (FIG. 2 (A)) in which the surface protective material was laminated | stacked is then provided to a decoloring process. As a decoloring process, the decolorization process by a laser or the decolorization process by contact with the basic solution containing a basic compound, etc. are mentioned, for example. Preferably, the contact is with a basic solution. By forming the decolorizing portion by contact with the basic solution, the strength of the decolorizing portion can be improved. Moreover, the transparency of a bleaching part can be maintained over time. As described above, the exposed portion 13 subjected to the decolorizing treatment may be a recessed portion. Therefore, even when the decolorizing treatment is performed by contact with the basic solution, the basic solution can be easily brought into contact only with the exposed portion 13.

The intermediate discoloration part 14 is formed by performing decolorization process with respect to the part 13 exposed from the surface protection material of the resin film of FIG. 2 (A) (FIG. 2 (B)). The intermediate decolorizing portion 14 is designed to be larger than the decolorizing portion 13 of the finally obtained polarizer 10. The part larger than the discoloration part 11 of the polarizer 10 is cut | disconnected with the resin film protected by the outer surface protection material in the cutting process mentioned later.

Arbitrary suitable methods can be employ | adopted as the contact method of basic solution. For example, the method of dripping, coating, and spraying a basic solution with respect to a resin film, and the method of immersing a resin film in a basic solution are mentioned.

Arbitrary suitable basic compounds can be used as said basic compound. Examples of the basic compound include hydroxides of alkali metals such as sodium hydroxide, potassium hydroxide and lithium hydroxide, hydroxides of alkaline earth metals such as calcium hydroxide, inorganic alkali metal salts such as sodium carbonate, organic alkali metal salts such as sodium acetate, aqueous ammonia and the like. Can be mentioned. Among these, hydroxides of alkali metals and / or alkaline earth metals are preferably used, and sodium hydroxide, potassium hydroxide and lithium hydroxide are more preferably used. The dichroic substance can be ionized efficiently, and a bleaching part (middle bleaching part) can be formed more simply. These basic compounds may be used alone or in combination of two or more thereof.

Arbitrary suitable solvent can be used as a solvent of a basic solution. Specifically, alcohol, such as water, ethanol, methanol, ether, benzene, chloroform, and these mixed solvents are mentioned. Among these, since ionized dichroic substance can transition to a solvent favorably, water and alcohol are used preferably.

The concentration of the basic solution is, for example, 0.01 N to 5 N, preferably 0.05 N to 3 N, and more preferably 0.1 N to 2.5 N. If the concentration is in this range, the desired decolorizing part can be formed well.

The liquid temperature of a basic solution is 20 degreeC-50 degreeC, for example. The contact time of a resin film and a basic solution can be set according to the thickness of a resin film, the kind of basic compound, and the density | concentration of a basic solution, for example, for 5 second-30 minutes.

A-4. Reduction Treatment of Basic Compound

When decolorization is carried out by contacting the basic solution, hydroxides of alkali metals and / or alkaline earth metals may remain in the contact portions. In addition, by contacting the basic solution with the resin film, a metal salt of an alkali metal and / or an alkaline earth metal can be generated at the contact portion. These can generate hydroxide ions, and the generated hydroxide ions can act (decompose and reduce) the dichroic substance (for example, an iodine complex) present around the contact portion, thereby widening the discoloration region. Therefore, it is preferable to reduce the alkali metal and / or alkaline earth metal contained in a resin film in the contact part which contacted the basic solution after contact with the said basic solution. By reducing alkali metal and / or alkaline earth metal, a discoloration part excellent in dimensional stability can be obtained.

As said reduction method, Preferably, the method of making a process liquid contact a contact part with basic solution is used. According to such a method, an alkali metal and / or alkaline-earth metal can be shifted with a process liquid in a resin film, and the content can be reduced.

Arbitrary suitable methods can be employ | adopted as a contact method of a process liquid. For example, the method of dripping, coating and spraying a process liquid with respect to the contact part with basic solution, and the method of immersing a contact part with basic solution in basic solution are mentioned.

It is preferable to perform a reduction process in the state which laminated | stacked the said surface protective material (especially when the temperature of a process liquid is 50 degreeC or more). According to such an aspect, the fall of the polarization characteristic by a process liquid can be prevented in the site | parts other than the contact part with basic solution.

The treatment liquid may contain any suitable solvent. As a solvent, alcohol, such as water, ethanol, methanol, ether, benzene, chloroform, and these mixed solvents are mentioned, for example. Among them, water and alcohols are preferably used from the viewpoint of efficiently transferring alkali metals and / or alkaline earth metals. Arbitrary suitable water can be used as water. For example, tap water, pure water, deionized water, etc. are mentioned.

The temperature of the processing liquid at the time of contact is 20 degreeC or more, for example, Preferably it is 50 degreeC or more, More preferably, it is 60 degreeC or more, More preferably, it is 70 degreeC or more. If it is such temperature, alkali metal and / or alkaline-earth metal can be efficiently transferred to a process liquid. Specifically, the swelling ratio of the resin film can be significantly improved, and the alkali metal and / or alkaline earth metal in the resin film can be physically removed. On the other hand, the temperature of water is substantially 95 degrees C or less.

Contact time can be suitably adjusted according to a contact method, the temperature of a process liquid (water), the thickness of a resin film, etc. For example, when immersed in hot water, the contact time is preferably 10 seconds to 30 minutes, more preferably 30 seconds to 15 minutes, still more preferably 60 seconds to 10 minutes.

In one embodiment, an acidic solution is used as said processing liquid. By using an acidic solution, hydroxide of alkali metal and / or alkaline-earth metal which remain | survives in a resin film can be neutralized, and the alkali metal and / or alkaline-earth metal in a resin film can be chemically removed.

Arbitrary suitable acidic compounds can be used as an acidic compound contained in an acidic solution. As an acidic compound, inorganic acids, such as hydrochloric acid, a sulfuric acid, nitric acid, hydrogen fluoride, a boric acid, organic acids, such as formic acid, an oxalic acid, a citric acid, an acetic acid, benzoic acid, etc. are mentioned, for example. The acidic compound contained in the acidic solution is preferably an inorganic acid, more preferably hydrochloric acid, sulfuric acid, or nitric acid. These acidic compounds may be used independently and may be used in combination of 2 or more type.

As an index of the acidity of an acidic compound, an acid dissociation constant (pKa) is mentioned, for example. Specifically, pKa of an acidic compound becomes like this. Preferably it is less than 9.2, More preferably, it is 5 or less. pKa may be measured using any suitable measuring apparatus, and may refer to the value described in literature, such as the 5th edition of a chemical handbook basic edition (Japanese Chemical Society, Maruzen Publishing). Moreover, in the acidic compound dissociated in multiple stages, the value of pKa may change in each step. In the case of using such an acidic compound, any of the values of pKa in each step is used in the above range. In addition, in this specification, pKa says the value in 25 degreeC aqueous solution.

Examples of acidic compounds that can satisfy the pKa include hydrochloric acid (pKa: -3.7), sulfuric acid (pK ₂ : 1.96), nitric acid (pKa: -1.8), hydrogen fluoride (pKa: 3.17), boric acid ( inorganic acids such as pKa: 9.2), formic acid (pKa: 3.54), oxalic acid (pK ₁ : 1.04, pK ₂ : 3.82), citric acid (pK ₁ : 3.09, pK ₂ : 4.75, pK ₃ : 6.41), acetic acid (pKa: 4.8) and organic acids, such as benzoic acid (pKa: 4.0), etc. are mentioned.

In addition, the solvent of an acidic solution (treatment liquid) is as above-mentioned, and also in this form using an acidic solution as a process liquid, physical removal of the alkali metal and / or alkaline-earth metal in the said resin film may occur.

The concentration of the acidic solution is, for example, 0.01 N to 5 N, preferably 0.05 N to 3 N, and more preferably 0.1 N to 2.5 N.

The liquid temperature of the said acidic solution is 20 degreeC-50 degreeC, for example. The contact time with respect to an acidic solution can be set according to the thickness of a resin film, the kind of acidic compound, and the density | concentration of an acidic solution, for example, for 5 second-30 minutes.

A-5. Removal of surface protective material

After the decolorization treatment is performed, the surface protective material is removed from the resin film at any suitable step (Fig. 2 (C)). The surface protective material is removed by any suitable method. For example, when using a surface protection film as a surface protection material, it can remove by peeling a surface protection film from a resin film. In the part protected by the inner surface protection material 21, the dyeing part corresponded to the dyeing | staining part 12 of a polarizer is left. In addition, the outer dyeing portion 15 remains in the portion protected by the outer surface protective material 22.

A-6. Cutting of the outer edge of the discoloration part

Subsequently, by cutting and removing the part (outer side dyeing part 15 of FIG. 2C) in which the surface protective material of the peripheral edge part of the resin film was laminated | stacked including a part of intermediate | middle decolorization part 14, it removed at least The polarizer in which the discoloration part was formed in part is obtained. In the example of illustration, in the resin film after cutting, the inside (broken part of FIG. 2 (C)) of the intermediate | middle decolorization part 14 is cut | disconnected so that the desired decolorization part 11 may be formed. By cutting off the part where the surface protective material of the peripheral edge part of the resin film was laminated | stacked including a part of intermediate | middle decolorization part 14, the outer side (for example, the side of a resin film) of the outer surface protective material 22 is a basic solution. Even in the case of contact with, the contact portion can be removed from the desired polarizer. Therefore, the basic solution penetrates from the outside of the surface protective material, and as a result, the dyeing part 12 can be prevented from discoloring. In addition, by cutting off the portion where the decoloring treatment has been performed (intermediate decolorizing portion), generation of cracks from the cut portion can be prevented. When cut | disconnecting the inside of a discoloration part, you may perform a cutting process, without removing an outer surface protection material.

Arbitrary suitable means can be used as a cutting method. For example, punching blades, such as a laser, a cutter, a Thompson blade, and a peak blade, etc. are mentioned. Cutting is preferably carried out by a laser. By using a laser, it can cope with the high precision with the machining request which is difficult to cope with thomson blade, peak blade, etc., such as mold release processing. As the type and irradiation conditions of the laser, any suitable laser species and irradiation conditions may be selected according to the material and thickness of the protective material, the thickness of the polarizer, and the like.

A-7. Other treatment

The manufacturing method of the polarizer of this invention may further contain arbitrary other appropriate processing processes other than said various processing processes. Other treatment steps include removal of basic solution and / or acidic solution, and washing.

As a specific example of the removal method of basic solution and / or acidic solution, wiping removal by a waste etc., suction removal, natural drying, heat drying, ventilation drying, reduced pressure drying, etc. are mentioned. The said drying temperature is 20 degreeC-100 degreeC, for example.

The washing treatment is carried out by any suitable method. As a solution used for a washing process, pure water, alcohols, such as methanol and ethanol, an acidic aqueous solution, these mixed solvents, etc. are mentioned, for example. The cleaning treatment can be carried out at any suitable step. You may perform a washing | cleaning process in multiple times.

B. polarizer

The polarizer obtained by the manufacturing method of this invention has a discoloration part formed in at least one part of a dyeing | staining part and a peripheral edge part. By having a discoloration part in at least one part of a peripheral edge part, it becomes possible to apply various colors, without affecting the color of a polarizer. Therefore, it becomes possible to provide an image display device of more various designs. Moreover, when used for the image display apparatus provided with a camera and a sensor, these functions can be exhibited highly.

Light polarizer (dyeing part), Preferably shows absorption dichroism in the range of wavelength 380nm-780nm. The single transmittance (Ts) of the polarizer (dyed part) is preferably 39% or more, more preferably 39.5% or more, still more preferably 40% or more, particularly preferably 40.5% or more. In addition, the theoretical upper limit of a single transmittance is 50%, and a practical upper limit is 46%. The single transmittance (Ts) is a Y value measured by a 2-degree field of view (C light source) of JIS Z8701 and corrected for visibility, and measured using, for example, a brown rice spectroscopic system (manufactured by Lambda Vision, LVmicro). Can be. The polarization degree of the polarizer (dyed part) is preferably 99.8% or more, more preferably 99.9% or more, and still more preferably 99.95% or more.

The bleaching portion may be formed in any suitable size. The width | variety of a discoloration part is 1 mm or more, Preferably it is 3 mm or more, More preferably, it is 5 mm or more. By such a range, it becomes possible to apply various colors, without affecting the color of a polarizer. Therefore, it becomes possible to provide an image display device of more various designs. Moreover, when used for the image display apparatus provided with a camera and a sensor, these functions can be exhibited highly. In addition, even when moisture penetrates from the end of the polarizer, it is possible to prevent the moisture from remaining in the discoloring portion and reaching the dyeing portion. The width | variety of a discoloration part is 30 mm or less from a viewpoint of ensuring a dyeing part.

The transmittance of the bleaching part (for example, the transmittance measured by light having a wavelength of 550 nm at 23 ° C.) is preferably 50% or more, more preferably 60% or more, still more preferably 75% or more, particularly preferably Preferably 90% or more. When the transmittance is such a range, various colors can be applied without affecting the color of the polarizer. Therefore, it becomes possible to provide an image display device of more various designs.

Content of the dichroic substance of a discoloration part becomes like this. Preferably it is 1.0 weight% or less, More preferably, it is 0.5 weight% or less, More preferably, it is 0.2 weight% or less. If the content of the dichroic substance in the decolorizing portion is in such a range, the decolorizing portion having the desired transparency can be obtained. On the other hand, the lower limit of content of the dichroic substance of a discoloration part is normally a detection limit value or less. In addition, when using iodine as a dichroic substance, iodine content is calculated | required by the analytical curve previously created using the standard sample from the X-ray intensity measured by the fluorescent X-ray analysis, for example.

C. Polarizer

The polarizer obtained by the manufacturing method of this invention is normally used as a polarizing plate. This polarizing plate is typically used by laminating a protective layer (protective film) on at least one side thereof. As a forming material of a protective film, For example, cellulose resins, such as diacetyl cellulose and a triacetyl cellulose, (meth) acrylic-type resin, cycloolefin resin, olefin resins, such as polypropylene, polyethylene terephthalate resin, etc. Ester resins, polyamide resins, polycarbonate resins, copolymer resins thereof, and the like.

On the surface which does not laminate | stack a polarizer of a protective film, the hard coat layer, an anti-reflective process layer, and the treatment layer for the purpose of diffused or antiglare may be formed as a surface treatment layer.

The thickness of a protective film becomes like this. Preferably it is 10 micrometers-100 micrometers. The protective film is typically laminated on the polarizer via an adhesive layer (specifically, an adhesive layer, an adhesive layer). The adhesive layer is typically formed of a PVA-based adhesive or an activated energy ray curable adhesive. The pressure-sensitive adhesive layer is typically formed of an acrylic pressure-sensitive adhesive.

D. Image Display

The polarizing plate is used for any suitable use. An image display apparatus is mentioned as a use of a polarizing plate. As an image display apparatus, a liquid crystal display device and an organic EL device are mentioned, for example. Specifically, a liquid crystal display device is provided with the liquid crystal panel containing a liquid crystal cell and the said polarizer arrange | positioned at the one side or both sides of this liquid crystal cell. An organic EL device is provided with the organic EL panel by which the said polarizer was arrange | positioned at the visual recognition side. As mentioned above, since the polarizer obtained by the manufacturing method of this invention has a discoloration part in at least one part of a periphery, various colors can be applied without affecting the color of a polarizer. Therefore, the image display apparatus of various designs can be provided. Moreover, when used for the image display apparatus provided with a camera and a sensor, these functions can be exhibited highly.

Example

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples.

EXAMPLE

As a base material, an amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymer PET) film (thickness: 100 micrometers) of 0.75% of water absorption and Tg75 degreeC was used. Corona treatment is performed on one side of the substrate, and polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (polymerization degree 1200, acetoacetyl modification degree 4.6%, saponification degree 99.0 mol) % Aqueous solution containing Nippon Synthetic Chemical Industry Co., Ltd. product, brand name "Gocefimer Z200") in the ratio of 9: 1, is apply | coated and dried at 25 degreeC, the PVA system resin layer of thickness 11micrometer is formed, and a laminated body is formed, Prepared.

The obtained laminated body was uniaxially stretched by the free end uniaxially by 2.0 times in the 120 degreeC oven between rolls from which a circumferential speed differs (longitudinal direction).

Subsequently, the laminate was immersed in an insolubilization bath (a boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 30 ° C. (insolubilization treatment).

Subsequently, it was immersed in the dyeing bath of 30 degreeC of liquid temperature, adjusting iodine density | concentration and immersion time so that a polarizing plate might become predetermined | prescribed transmittance | permeability. In this Example, 0.2 weight part of iodine was mix | blended with respect to 100 weight part of water, and it was immersed for 60 second in the aqueous solution of iodine obtained by mix | blending 1.5 weight part of potassium iodide (dyeing process).

Subsequently, it was immersed for 30 second in the crosslinking bath of 30 degreeC of liquid temperature (3 weight part of potassium iodide, and 3 weight part of boric acid solution mix | blended with respect to 100 weight part of water) (crosslinking process).

Thereafter, the laminate is immersed in a boric acid aqueous solution (aqueous solution obtained by blending 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 70 ° C, between rolls having different circumferential speeds. Uniaxial stretching was performed so that a total draw ratio might be 5.5 times in the longitudinal direction (length direction) (underwater stretching).

Then, the laminated body was immersed in the washing bath of 30 degreeC of liquid temperature (the aqueous solution obtained by mix | blending 4 weight part of potassium iodide with respect to 100 weight part of water) (washing process).

Subsequently, a PVA-based resin aqueous solution (Nippon Synthetic Chemical Co., Ltd. product, brand name "High Sepamer (Z) -200", resin concentration: 3 weight%) was apply | coated to the PVA system resin layer surface of a laminated body, and a protective film (25 micrometers in thickness) was bonded together, and it heated for 5 minutes in the oven maintained at 60 degreeC. Then, the base material was peeled from the PVA system resin layer, and the polarizing plate (polarizer (42.3% of transmittance, 5 micrometers in thickness) / protective film) was obtained.

On the polarizer side surface of the obtained polarizing plate, the surface protective material (PET film of 38-micrometer-thick (Mitsubishi Chemical Polyester Film Co., Ltd. make, brand name: diafoil T100C)) was laminated | stacked through the acrylic adhesive layer (10 micrometers in thickness). As shown in FIG.2 (A), the surface protection material is a part (inner surface protection material 21 of FIG. 2 (A)) corresponded to a dyeing | dye part, and the outer side surface protection material 22 of a discoloration part outer edge (FIG. 2 (A). )). Moreover, the same surface protection material was laminated | stacked similarly so as to protect the whole surface of a protective film, and the laminated body was obtained. The obtained laminated body was immersed in the basic solution (sodium hydroxide aqueous solution, 1 mol / L (1N)) of normal temperature for 8 second, and hydrochloric acid of 0.1 mol / L (0.1N) for 30 second, respectively. Then, it dried at 60 degreeC and obtained the polarizer which has an intermediate discoloration part.

Subsequently, each surface protective material was peeled off, and the inner 20 mm of the middle decolorized part was cut at the boundary of the outer decolorized part and the intermediate decolorized part with a laser (type: CO ₂ laser, output: 40 W, cutting speed: 5 m / min), Polarizer was obtained. The photograph of the obtained polarizer is shown to FIG. 3 (a). As a result of confirming the state of the discoloration part of the obtained polarizer visually and a photograph, the wrinkle by the swelling of a resin film and peeling of the polarizer from a protective film were not confirmed.

(Comparative Example)

A polarizer was produced in the same manner as in Example except that the outer surface protective film was not used (the peripheral edge of the polarizer was decolored). The photograph of the obtained polarizer is shown to FIG. 3 (b). As a result of visually and photographing confirming the state of the discoloration part of the obtained polarizer peripheral edge part, the wrinkle by the swelling of the resin film was confirmed. Moreover, the part from which the polarizer peeled from the protective film was also confirmed, and there existed a problem in practical use.

The polarizer of this invention is used suitably for image display apparatuses, such as a liquid crystal display device and an organic EL device.

10 polarizer
11 discoloration part
12 Dyeing Department
13 exposed parts
14 Medium Bleaching Part
21 Inner Surface Protective Materials
22 Outer surface protective material

Claims (8)

As a manufacturing method of light polarizer which has a dyeing part and the decolorization part formed in at least one part of the peripheral part,
Dyeing the resin film,
Laminating | stacking a surface protective material on the part corresponded to the said dyeing | dying part of the resin film processed by dyeing, and the peripheral edge part of the said resin film,
Decolorizing the resin film in a state of laminating the surface protective material to form an intermediate decolorizing part,
Removing the surface protective material, and
Including the part of the said intermediate discoloration part, The manufacturing method of the polarizer which includes cutting the part in which the said surface protective material of the peripheral edge part of the said resin film was laminated | stacked. According to claim 1,
The said discoloration part is formed in the whole peripheral edge part of a polarizer. The method of claim 1,
The manufacturing method of light polarizer which said decolorization process is performed by making a basic solution contact the dye film process. The method of claim 3, wherein
A method of producing a polarizer, comprising further contacting an acidic solution with a portion in contact with the basic solution. The method according to any one of claims 1 to 4,
The said cutting is performed by the laser, The manufacturing method of light polarizer. The method according to claim 3 or 4,
The manufacturing method of light polarizer which further includes laminating | stacking a protective layer on the said resin film. The method of claim 6,
The method of manufacturing a polarizer further comprising laminating another surface protective material on the protective layer. The method of claim 7, wherein
The manufacturing method of light polarizer which performs the said discoloration process in the state in which the said other surface protection material was laminated | stacked.

Images