JP7484728B2 - Method for manufacturing polarizing plate and method for manufacturing display device - Google Patents

Description

The present invention relates to a laminate, a polarizing plate, a method for manufacturing a laminate, a method for manufacturing a polarizing plate, and a method for manufacturing a display device.

Display devices such as liquid crystal display devices and organic electroluminescence (EL) display devices have traditionally been required to have a large display area, be light in weight, and be thin. As a result, there has also traditionally been a demand for thin panels that make up the display devices.

In display devices, polarizing plates that include a polarizer and a protective film to protect the polarizer are generally used. In order to construct thin display devices, thinner polarizing plates are also required. In particular, polarizers may shrink in the environment in which the display device is used, and warping due to such shrinkage can be a problem in thin, large-area display devices. Therefore, by adopting a thin polarizer, such as one with a thickness of 10 μm or less, not only can the thickness of the display device be reduced by reducing the thickness of the polarizer itself, but the occurrence of warping as described above can also be reduced.

However, when attempting to manufacture such a thin polyvinyl alcohol polarizer using conventional manufacturing methods, the polarizer frequently melts. Several methods have been proposed as a way to prevent such meltdown of the polarizer and to manufacture a polarizing plate that includes a thin polarizer.

For example, Patent Document 1 proposes a method in which an unstretched polyvinyl alcohol-based film is attached to a base film made of unstretched high-density polyethylene to form a laminate, and the laminate is stretched, and then the base film is peeled off to obtain a polyvinyl alcohol-based film.

JP 2016-505404 A (Corresponding Publication: U.S. Patent Application Publication No. 2016/084990)

When a thin polarizing plate is manufactured by the method described in Patent Document 1, a retardation may occur in the substrate film after the stretching process due to the fact that the laminate is stretched at a high stretch ratio. In such a case, it is difficult to use the substrate film as it is as a polarizing plate protective film, and the substrate film is peeled off and discarded, resulting in waste of material.
Therefore, we have investigated the production of a polarizing plate using a laminate in which a stretched polyvinyl alcohol resin film and an unstretched base film are bonded together via a polyvinyl alcohol adhesive. However, in this method, the polyvinyl alcohol adhesive permeates the stretched polyvinyl alcohol resin film, which can cause wrinkles and voids in the laminate and the polarizing plate.

Therefore, the present invention aims to provide a laminate and a manufacturing method thereof in which a resin layer can be used as a protective film, which can be efficiently manufactured even if it is thin, and which prevents the occurrence of wrinkles and voids, a polarizing plate using the laminate and a manufacturing method thereof, and a manufacturing method for a display device using the polarizing plate.

As a result of investigations to solve the above problems, the inventors found that the above problems can be solved by using a laminate having a polarizer material film having a predetermined phase difference and a predetermined thickness, and a resin layer provided directly on the polarizer material film, and thus completed the present invention.
Therefore, according to the present invention, the following [1] to [21] are provided.
[1] A laminate having a polarizer material film and a resin layer provided directly on the polarizer material film,
The retardation Re1 in the in-plane direction of the polarizer material film is greater than 50 nm,
The laminate, wherein the thickness T1 of the polarizer material film is 45 μm or less.
[2] The laminate according to [1], wherein the polarizer material film is a film obtained by stretching at a stretching ratio of X times.
[3] The laminate according to [2], wherein X satisfies 1.5≦X≦5.5.
[4] The retardation Re2 in the in-plane direction of the stretched resin layer is 0 nm or more and 20 nm or less,
The stretched resin layer is a stretched product of the resin layer in a stretched laminate, and the stretched laminate is a stretched product obtained by uniaxially stretching the laminate at a free end by 4.0 times at a temperature condition of 50°C to 120°C. The laminate according to any one of [1] to [3].
[5] The laminate according to any one of [1] to [4], wherein the polarizer material film is a polyvinyl alcohol resin film.
[6] The laminate according to [5], wherein the polyvinyl alcohol resin film has a transmittance of 50% or more for light having a wavelength of 550 nm.
[7] The laminate according to any one of [1] to [6], wherein the resin layer is made of a cycloolefin resin.
[8] The cycloolefin resin contains a cycloolefin polymer,
The cycloolefin polymer comprises a polymer block [A] mainly composed of a repeating unit [I] derived from an aromatic vinyl compound;
The laminate according to [7], which is a hydrogenated block copolymer [D] obtained by hydrogenating a block copolymer [B] composed mainly of a repeating unit [I] derived from an aromatic vinyl compound and a repeating unit [II] derived from a linear conjugated diene compound, or a block copolymer [D] composed mainly of a repeating unit [II] derived from a linear conjugated diene compound and a polymer block [B] composed mainly of a repeating unit [I] derived from a linear conjugated diene compound.
[9] The resin layer is a layer made of a resin,
The resin has a melt flow rate of 1 g/10 min or more and a tensile modulus E of 50 MPa or more and 1200 MPa or less,
The laminate according to any one of [1] to [8], wherein the melt flow rate is a value measured at 190° C. under a load of 2.16 kg.
[10] The laminate according to any one of [1] to [9], wherein the resin layer contains a plasticizer, a softener, or both.
[11] The laminate according to [10], wherein the plasticizer, the softener, or both of them are at least one selected from an ester-based plasticizer and an aliphatic hydrocarbon polymer.
[12] The laminate according to any one of [1] to [11], wherein the resin layer contains an organometallic compound.
[13] A polarizing plate which is a uniaxially stretched product of the laminate according to any one of [1] to [12].
[14] A first step of stretching a raw film containing a polarizer material to obtain a polarizer material film;
a second step of applying a resin to one surface of the polarizer material film to form a coating layer;
and a third step of drying the coating layer, in this order.
[15] The method for producing a laminate according to [14], wherein the stretching ratio in the first step is X times, and X satisfies 1.5≦X≦5.5.
[16] The method for producing a laminate according to [14] or [15], further comprising a fourth step of activating the surface of the polarizer material film before the second step.
[17] A method for producing a polarizing plate, comprising the steps of:
A step of preparing a laminate according to any one of [1] to [12] or producing a laminate by the method for producing a laminate according to any one of [14] to [16];
a fifth step of dyeing the laminate with a dichroic dye;
and a sixth step of uniaxially stretching the laminate.
[18] The method for producing a polarizing plate according to [17], wherein in the sixth step, the stretching ratio is Z times, and Z satisfies 1.2≦Z≦5.0.
[19] The method for producing a polarizing plate according to [17] or [18], wherein X and Z satisfy 5.1≦X*Z≦9.0.
[20] The method for producing a polarizing plate according to any one of [17] to [19], further comprising a seventh step of laminating a protective film to one or both of a surface of the laminate facing the polarizer material film and a surface of the laminate facing the resin layer after the fifth step, the sixth step, or both of these steps.
[21] A method for manufacturing a display device, comprising:
A method for producing a polarizing plate according to any one of [17] to [20], and an eighth step of laminating the polarizing plate on a panel,
The method for manufacturing a display device, wherein the panel is selected from a liquid crystal panel, an organic electroluminescence panel, and a micro LED panel.

According to the present invention, it is possible to provide a laminate and a method for manufacturing the same, a polarizing plate using the laminate and a method for manufacturing the same, and a method for manufacturing a display device using the polarizing plate, in which the resin layer can also be used as a protective film and can be efficiently manufactured even if it is thin, and the occurrence of wrinkles and voids is prevented.

FIG. 1 is a cross-sectional view that illustrates a laminate according to a first embodiment. FIG. 2 is a schematic diagram showing an example of a manufacturing apparatus used in the method for manufacturing a laminate according to the first embodiment. FIG. 3 is a schematic diagram showing an example of a manufacturing apparatus used in the method for manufacturing a polarizing plate according to the first embodiment. FIG. 4 is a cross-sectional view that illustrates a polarizing plate manufactured using the laminate according to the first embodiment. FIG. 5 is a cross-sectional view that illustrates a polarizing plate manufactured by the method for manufacturing a polarizing plate according to the second embodiment. FIG. 6 is a cross-sectional view showing a schematic diagram of a display device manufactured by the manufacturing method of a display device according to the third embodiment. FIG. 7 is a cross-sectional view showing a schematic diagram of a display device manufactured by the manufacturing method of a display device according to the fourth embodiment.

The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples described below, and may be modified as desired without departing from the scope of the claims of the present invention and their equivalents.

In this application, a "long" film refers to a film having a length that is 5 times or more the width of the film, preferably 10 times or more the width of the film, specifically a film having a length that is long enough to be wound into a roll for storage or transportation. There is no particular upper limit to the ratio of the length to the width of the film, but it may be, for example, 100,000 times or less.

In this application, the retardation Re in the in-plane direction and the retardation Rth in the thickness direction of the film are calculated according to the formulas Re = (nx - ny) x d and Rth = [{(nx + ny) / 2} - nz] x d. The Nz coefficient of the film is a value expressed as [(nx - nz) / (nx - ny)], and can also be expressed as [(Rth / Re) + 0.5]. Here, nx is the refractive index in the slow axis direction in the film's plane (maximum in-plane refractive index), ny is the refractive index in the in-plane direction perpendicular to the slow axis in the film's plane, nz is the refractive index in the thickness direction of the film, and d is the thickness of the film (nm). Unless otherwise specified, the measurement wavelength is 550 nm, which is a typical wavelength in the visible light region.

[Embodiment 1: Laminate and its manufacturing method, polarizing plate and its manufacturing method]
Hereinafter, a laminate according to embodiment 1, which is one embodiment of the present invention, a method for producing the same, and a polarizing plate using the laminate and a method for producing the same will be described with reference to FIGS. 1 to 4. FIG.

[1. Laminate]
The laminate of the present invention includes a polarizer material film and a resin layer provided directly on the polarizer material film. In the laminate of the present invention, the polarizer material film has an in-plane retardation Re1 of more than 50 nm and a thickness T1 of 45 μm or less.
As is clear from the context, in the present invention, the "resin layer" is a layer separate from the polarizer material film.
In the present invention, a "resin layer directly provided" on a polarizer material film refers to a resin layer that is provided on the surface of a layer of material that constitutes the polarizer material film, and as a result, is in direct contact with the surface of the polarizer material film.

Figure 1 is an example of a cross-sectional view showing a laminate 10 of embodiment 1 of the present invention. As shown in Figure 1, the laminate 10 of this embodiment includes a polarizer material film 11 and a resin layer 12 provided on one side (the upper side shown in the figure) of the polarizer material film 11. The laminate 10 of the present invention is a material for producing a polarizer and a polarizing plate including a polarizer.

[Polarizer material film]
The polarizer material film is a film for producing a polarizer (film for polarizer). In the present invention, the polarizer material film is a film having an in-plane retardation Re1 of more than 50 nm and a thickness T1 of 45 μm or less. The polarizer material film can be obtained by stretching an unstretched film containing a polarizer material so that the in-plane retardation Re1 is more than 50 nm and the thickness T1 is 45 μm or less. The polarizer material film is a (stretched) film containing a polarizer material. In the present invention, a film for obtaining a polarizer material film that has not been subjected to a stretching process to obtain a predetermined retardation and thickness (unstretched film containing a polarizer material) is called a "raw film". The raw film contains a polarizer material.

In the present invention, the raw film is not necessarily limited as long as it can achieve the object of the present invention, but polyvinyl alcohol resin film is preferred due to its high cost performance.

In the present invention, the polyvinyl alcohol resin film (hereinafter sometimes referred to as "PVA resin film") that can be used as the raw film is not necessarily limited, but it is preferable to use one manufactured by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate, in terms of availability, etc. The polyvinyl alcohol (hereinafter sometimes referred to as "PVA") contained in the PVA resin film preferably has a degree of polymerization in the range of 500 to 8000, and a degree of saponification of 90 mol% or more, from the viewpoint of excellent stretchability and the polarization performance of the resulting polarizer. Here, the degree of polymerization is the average degree of polymerization measured in accordance with the description of JIS K6726-1994, and the degree of saponification is a value measured in accordance with the description of JIS K6726-1994. The more preferable range of the degree of polymerization is 1000 to 6000, and even more preferably 1500 to 4000. The more preferable range of the degree of saponification is 95 mol% or more, and even more preferably 99 mol% or more. The PVA may be a copolymer of vinyl acetate and another monomer copolymerizable therewith, or a graft polymer.

In the present invention, the method for producing the PVA resin film that can be used as the raw film is not particularly limited, and it can be produced by any method such as a known method. Examples of the production method include a casting film production method, a wet film production method (discharge into a poor solvent), a dry-wet film production method, a gel film production method (a method in which a PVA aqueous solution is cooled and gelled, and then the solvent is extracted and removed to obtain a PVA resin film), and a combination of these, in which a PVA solution in which PVA is dissolved in a solvent is used as the film production stock solution. Another example of the production method is a melt extrusion film production method in which a PVA containing a solvent is melted and used as the film production stock solution. Among these, the casting film production method and the melt extrusion film production method are preferred because they can produce a PVA resin film with high transparency and little coloring, and the melt extrusion film production method is more preferred because it can produce a high film production speed.

In the present invention, the PVA resin film that can be used as the raw film preferably contains 0.01 to 30% by weight of a plasticizer such as a polyhydric alcohol such as glycerin, relative to the PVA, in order to improve the mechanical properties and the processability during secondary processing, and also preferably contains 0.01 to 1% by weight of a surfactant, such as an anionic surfactant or a nonionic surfactant, relative to the PVA, in order to improve the handling properties and the film appearance.

The PVA resin film that can be used as the raw film may further contain optional components such as antioxidants, UV absorbers, lubricants, pH adjusters, inorganic fine particles, colorants, preservatives, antifungal agents, polymer compounds other than the above-mentioned components, and moisture, as necessary. The PVA resin film may contain one or more of the above-mentioned optional components.

The thickness of the raw film is preferably 60 μm or less, more preferably 45 μm or less, even more preferably 30 μm or less, and preferably 10 μm or more, more preferably 15 μm or more, even more preferably 20 μm or more. When the thickness of the raw film is equal to or greater than the lower limit of the above range, a polarizing plate having a sufficiently high degree of polarization can be obtained, and when the thickness is equal to or less than the upper limit of the above range, the bending resistance of the polarizing plate can be effectively increased.

The polarizer material film may be a film obtained by stretching. The polarizer material film may be obtained by stretching the raw film. Examples of the stretching method include dry stretching and wet stretching. Dry stretching requires simpler equipment and steps than wet stretching, so the polarizer material film is preferably obtained by dry stretching. As for dry stretching, stretching methods such as tenter stretching, float stretching, and hot roll stretching can be used. Dry stretching refers to a stretching method in which stretching is performed under a gas atmosphere at a high temperature (e.g., 100°C or higher). An example of the gas used in dry stretching is air.

The conditions for stretching the raw film to form a polarizer material film can be appropriately selected so as to obtain the desired polarizer material film. For example, the stretching mode when stretching the raw film to form a polarizer material film can be any mode such as uniaxial stretching or biaxial stretching. In addition, when the raw film is a long film, the stretching direction can be any of the vertical direction (direction parallel to the longitudinal direction of the long film), horizontal direction (direction parallel to the width direction of the long film), and diagonal direction (direction that is neither vertical nor horizontal).

The polarizer material film may be a film stretched at a stretching ratio of X times. It is preferable that X satisfies 1.5≦X≦5.5. Such a polarizer material film can be obtained by stretching the original film at a stretching ratio of X times. In the present invention, X is preferably 1.5 or more, more preferably 2.0 or more, even more preferably 2.5 or more, and preferably 5.5 or less, more preferably 4.5 or less, and even more preferably 3.5 or less. In other words, the polarizer material film is preferably a film stretched at a stretching ratio of 1.5 times or more and 5.5 times or less, more preferably a film stretched at a stretching ratio of 2.0 times or more and 4.5 times or less, and even more preferably a film stretched at a stretching ratio of 2.5 times or more and 3.5 times or less. When X is set to the upper limit value or less of the above range, it is possible to prevent the occurrence of breakage when the original film is stretched to form a polarizer material film. In addition, when X is set to the lower limit value or more of the above range, it is possible to lower the stretching ratio when the laminate is stretched to obtain a polarizing plate. When the raw film is stretched in two or more directions, such as biaxial stretching, the stretching ratio X is the product of the respective stretching ratios.

The stretching temperature when dry stretching the raw film to form a polarizer material film is preferably 100°C or higher, more preferably 110°C or higher, and is preferably 150°C or lower, more preferably 140°C or lower. When the dry stretching temperature is within the above range, a polarizer material film with a uniform thickness can be obtained.

The polarizer material film is preferably a PVA resin film. As a PVA resin film that can be used as a polarizer material film, a film having a transmittance of light with a wavelength of 550 nm (hereinafter, "transmittance of light with a wavelength of 550 nm" is also referred to as "light transmittance") of 50% or more is preferable. As the PVA resin film, an uncolored film can be used. The light transmittance of such a PVA resin film is preferably 55% or more, more preferably 60% or more, and is preferably 99% or less, more preferably 97% or less.

The thickness T1 of the polarizer material film is preferably 45 μm or less, more preferably 35 μm or less, even more preferably 25 μm or less, and preferably 5 μm or more, more preferably 7 μm or more, even more preferably 10 μm or more. When the thickness of the polarizer material film is equal to or less than the upper limit of the above range, the contraction force of the polarizing plate can be effectively reduced, and when the thickness is equal to or greater than the lower limit of the above range, a polarizing plate having a sufficiently high degree of polarization can be obtained.

The in-plane retardation Re1 of the polarizer material film is preferably 50 nm or more, more preferably more than 50 nm, even more preferably 100 nm or more, particularly preferably 150 nm or more, and preferably 1500 nm or less, more preferably 1000 nm or less. By having the in-plane retardation Re1 of the polarizer material film be equal to or greater than the lower limit of the above range, the stretching ratio when the laminate is stretched to form a polarizing plate can be kept low, and the retardation of the resin layer after stretching can be kept low.

The shape and dimensions of the polarizer material film can be adjusted appropriately according to the desired application. For manufacturing efficiency, it is preferable that the polarizer material film is a long film.

[Resin layer]
The resin layer is a layer made of a resin. The resin layer may be a resin layer provided by applying a resin to a polarizer material film. Alternatively, the resin layer may be provided by directly thermocompressing a film-like resin onto the polarizer material film. "Direct thermocompression bonding" onto the polarizer material film means that the polarizer material film and the film-like resin that will become the resin layer are pressure-bonded without any adhesive or pressure-sensitive adhesive between the polarizer material film and the resin layer.

In the present invention, the resin constituting the resin layer is preferably a flexible resin that can be stretched at a high stretch ratio (e.g., 6.0 times) at low temperatures (e.g., 50 to 120°C). Examples of such resins include cycloolefin resins containing cycloolefin polymers, and resins having a melt flow rate of 1 g/10 min or more and a tensile modulus E of 50 MPa or more and 1200 MPa or less. The melt flow rate here is a value measured at 190°C and a load of 2.16 kg. Hereinafter, "melt flow rate measured at 190°C and a load of 2.16 kg" will also be simply referred to as "MFR".

[resin]
The cycloolefin resin is a resin containing a cycloolefin polymer. The cycloolefin polymer contained in the cycloolefin resin is preferably a hydrogenated block copolymer obtained by hydrogenating a block copolymer [D] consisting of a polymer block [A] mainly composed of a repeating unit [I] derived from an aromatic vinyl compound, a polymer block [B] mainly composed of a repeating unit [I] derived from an aromatic vinyl compound and a repeating unit [II] derived from a linear conjugated diene compound, or a polymer block [C] mainly composed of a repeating unit [II] derived from a linear conjugated diene compound. Examples of such hydrogenated block copolymers include polymers described in WO2000/32646, WO2001/081957, JP2002-105151A, JP2006-195242A, JP2011-13378A, WO2015/002020, and the like. The cycloolefin resin preferably has an MFR of 1 g/10 min or more and a tensile modulus E of 50 MPa or more and 1200 MPa or less, but the MFR, the tensile modulus E, or both may be outside the above ranges.
In the present invention, the "polymer block [A] mainly composed of repeating units [I] derived from an aromatic vinyl compound" may be "polymer block [A] containing more than 60 mass% of repeating units derived from an aromatic vinyl compound". The "polymer block [B] mainly composed of repeating units [I] derived from an aromatic vinyl compound and repeating units [II] derived from a linear conjugated diene compound" may be "polymer block [B] containing more than 60 mass% of repeating units [I] derived from an aromatic vinyl compound and repeating units [II] derived from a linear conjugated diene compound in total". The "polymer block [C] mainly composed of repeating units [II] derived from a linear conjugated diene compound" may be "polymer block [C] containing more than 60 mass% of repeating units derived from a linear conjugated diene compound".

In the present invention, the resin constituting the resin layer is preferably a resin having a melt flow rate of 1 g/10 min or more and a tensile modulus E of 50 MPa or more and 1200 MPa or less. The resin having an MFR of 1 g/10 min or more and a tensile modulus E of 50 MPa or more and 1200 MPa or less is preferably a cycloolefin resin, but may be a resin other than a cycloolefin resin.

The MFR of the resin is preferably 1 g/10 min or more, more preferably 3 g/10 min or more, even more preferably 5 g/10 min or more, and is preferably 300 g/10 min or less, more preferably 100 g/10 min or less. By setting the MFR of the resin to the lower limit or more, the retardation can be kept small when made into a polarizing plate, and by setting the MFR to the upper limit or less, the heat resistance can be increased.

The MFR of a resin can be measured using a melt indexer at a temperature of 190°C and a load of 2.16 kg in accordance with JIS-K-7210.

In the present invention, the tensile modulus E of the resin constituting the resin layer is preferably 50 MPa or more, more preferably 100 MPa or more, even more preferably 200 MPa or more, and preferably 1200 MPa or less, more preferably 1000 MPa or less, and even more preferably 800 MPa or less. By setting the tensile modulus E of the resin to a lower limit or more, the phase difference of the resin layer is reduced when the laminate is stretched to form a polarizing plate, and by setting it to an upper limit or less, the occurrence of breakage of the resin layer when the laminate is stretched can be prevented.

The tensile modulus can be measured in accordance with JIS K7127 using a tensile testing machine (manufactured by Instron Japan Company Limited, product name "Electromechanical Universal Material Testing Machine (5564)").

[Plasticizers and softeners]
In the present invention, the resin constituting the resin layer preferably contains a plasticizer, a softener, or both of these. By containing a plasticizer, a softener, or both of these, it is possible to reduce the retardation generated in the resin layer when the laminate is stretched to obtain a polarizing plate.

As the plasticizer and softener, those that can be uniformly dissolved or dispersed in the resin that constitutes the resin layer can be used. Specific examples of plasticizers and softeners include ester-based plasticizers such as ester-based plasticizers made of polyhydric alcohols and monovalent carboxylic acids (hereinafter referred to as "polyhydric alcohol ester-based plasticizers") and ester-based plasticizers made of polyvalent carboxylic acids and monovalent alcohols (hereinafter referred to as "polyvalent carboxylic acid ester-based plasticizers"), as well as phosphate ester-based plasticizers, carbohydrate ester-based plasticizers, and other polymer softeners.

Examples of polyhydric alcohols that are the raw materials for the ester-based plasticizers preferably used in the present invention include, but are not limited to, ethylene glycol, glycerin, and trimethylolpropane.

Examples of polyhydric alcohol ester plasticizers include ethylene glycol ester plasticizers, glycerin ester plasticizers, and other polyhydric alcohol ester plasticizers.

Examples of polycarboxylic acid ester plasticizers include dicarboxylic acid ester plasticizers and other polycarboxylic acid ester plasticizers.

Examples of phosphate ester plasticizers include alkyl phosphate esters such as triacetyl phosphate and tributyl phosphate; cycloalkyl phosphate esters such as tricyclopentyl phosphate and cyclohexyl phosphate; and aryl phosphate esters such as triphenyl phosphate and tricresyl phosphate.

Specific examples of carbohydrate ester plasticizers that are preferred include glucose pentaacetate, glucose pentapropionate, glucose pentabutyrate, sucrose octaacetate, and sucrose octabenzoate, with sucrose octaacetate being more preferred.

Specific examples of polymer softening agents include acrylic polymers such as aliphatic hydrocarbon polymers, alicyclic hydrocarbon polymers, polyethyl acrylate, polymethyl methacrylate, copolymers of methyl methacrylate and 2-hydroxyethyl methacrylate, and copolymers of methyl methacrylate, methyl acrylate, and 2-hydroxyethyl methacrylate; vinyl polymers such as polyvinyl isobutyl ether and poly N-vinylpyrrolidone; styrene polymers such as polystyrene and poly 4-hydroxystyrene; polyesters such as polybutylene succinate, polyethylene terephthalate, and polyethylene naphthalate; polyethers such as polyethylene oxide and polypropylene oxide; polyamide, polyurethane, polyurea, etc.

Specific examples of aliphatic hydrocarbon polymers include low molecular weight polymers such as polyisobutylene, polybutene, poly-4-methylpentene, poly-1-octene, ethylene-α-olefin copolymers, and hydrogenated products thereof; low molecular weight polymers such as polyisoprene, polyisoprene-butadiene copolymers, and hydrogenated products thereof. From the viewpoint of being easily dissolved or dispersed uniformly in the cycloolefin resin, it is preferable that the aliphatic hydrocarbon polymer has a number average molecular weight of 300 to 5,000.

These polymer softeners may be homopolymers consisting of one type of repeating unit, or copolymers having multiple repeating structures. Two or more of the above polymers may also be used in combination.

In the present invention, the plasticizer, softener, or both (hereinafter also referred to as "plasticizer, etc.") is preferably one or more selected from ester-based plasticizers and aliphatic hydrocarbon polymers, since these have particularly excellent compatibility with the resin constituting the resin layer.

The proportion of the plasticizer, etc. in the resin layer is preferably 0.2 parts by weight or more, more preferably 0.5 parts by weight or more, and even more preferably 1.0 parts by weight or more, relative to 100 parts by weight of the resin constituting the resin layer, and is preferably 50 parts by weight or less, more preferably 40 parts by weight or less. By setting the proportion of the plasticizer, etc. within the above range, the resin layer can be made to have a sufficiently low retardation even after it has been subjected to a polarizing plate manufacturing process including a stretching treatment.

[Organometallic Compounds]
In the present invention, the resin layer preferably contains an organometallic compound. By containing the organometallic compound, peeling of the resin layer can be more effectively suppressed when the laminate is stretched at a high stretch ratio (for example, wet stretched at a stretch ratio of 6.0).

An organometallic compound is a compound that contains at least one of a chemical bond between a metal and carbon and a chemical bond between a metal and oxygen, and is a metal compound having an organic group. Examples of organometallic compounds include organosilicon compounds, organotitanium compounds, organoaluminum compounds, and organozirconium compounds. Of these, organosilicon compounds, organotitanium compounds, and organozirconium compounds are preferred because of their excellent reactivity with polyvinyl alcohol, and organosilicon compounds are more preferred. One or more types of organometallic compounds may be used in combination.

Examples of the organometallic compound include, but are not limited to, organosilicon compounds represented by the following formula (1).
R ¹ _a Si(OR ² ) _4-a (1)
(In formula (1), ^R1 and ^R2 each independently represent a group selected from the group consisting of a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, an epoxy group, an amino group, a thiol group, an isocyanate group, and an organic group having 1 to 10 carbon atoms, and a represents an integer of 0 to 4.)

In formula (1), preferred examples of R ¹ include an epoxy group, an amino group, a thiol group, an isocyanate group, a vinyl group, an acrylic group, an aryl group, —CH ₂ OC _n H _2n+1 (n is an integer of 1 to 4), and an alkyl group having 1 to 8 carbon atoms.
In addition, in formula (1), preferred examples of R ² include a hydrogen atom, a vinyl group, an aryl group, an acrylic group, an alkyl group having 1 to 8 carbon atoms, -CH ₂ OC _n H _2n+1 (n is an integer of 1 to 4), and the like.

Examples of organosilicon compounds include epoxy-based organosilicon compounds such as 3-glycidoxypropyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, amino-based organosilicon compounds such as 3-aminopropyltrimethoxysilane and N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, isocyanurate-based organosilicon compounds such as tris-(trimethoxysilylpropyl)isocyanurate, mercapto-based organosilicon compounds such as 3-mercaptopropyltrimethoxysilane, and isocyanate-based organosilicon compounds such as 3-isocyanatepropyltriethoxysilane.

Examples of organic titanium compounds include titanium alkoxides such as tetraisopropyl titanate, titanium chelates such as titanium acetylacetonate, and titanium acylates such as titanium isostearate.

Examples of organic zirconium compounds include zirconium alkoxides such as normal propyl zirconate, zirconium chelates such as zirconium tetraacetylacetonate, and zirconium acylates such as zirconium stearate.

Examples of organoaluminum compounds include aluminum alkoxides such as aluminum sec-butoxide, and aluminum chelates such as aluminum trisacetylacetonate.

The ratio of the organometallic compound in the resin layer is preferably 0.005 parts by weight or more, more preferably 0.01 parts by weight or more, and even more preferably 0.03 parts by weight or more, relative to 100 parts by weight of the resin constituting the resin layer, and is preferably 1.0 part by weight or less, and more preferably 0.5 part by weight or less. By setting the ratio of the organometallic compound within the above range, peeling of the resin layer can be more effectively suppressed when the laminate is wet-stretched at a high ratio (e.g., a stretch ratio of 6.0).

[Optional ingredients]
The resin layer may contain optional components in addition to the resin, plasticizer, organometallic compound, etc. Examples of the optional components include stabilizers such as antioxidants, ultraviolet absorbers, and light stabilizers; resin modifiers such as lubricants; colorants such as dyes and pigments; and antistatic agents. These additives may be used alone or in combination of two or more, and the amount of each additive is appropriately selected.

[Thickness of resin layer]
The thickness of the resin layer in the laminate is preferably 3 μm or more, more preferably 5 μm or more, and preferably 60 μm or less, and more preferably 20 μm or less. When the thickness of the resin layer is equal to or more than the lower limit of the above range, melting of the polarizer in the polarizing plate formation process can be effectively prevented, and when the thickness is equal to or less than the upper limit of the above range, the retardation generated in the resin layer when the laminate is stretched to obtain a polarizing plate can be reduced.

[Resin layer Re2]
The Re2 of the resin layer is preferably 0 nm or more and 20 nm or less. Re2 is more preferably 0 nm or more, more preferably 10 nm or less, and particularly preferably 5 nm or less. When Re2 is equal to or less than the upper limit, the retardation generated in the resin layer can be reduced when the laminate 10 is stretched to form a polarizing plate.
Re2 is the in-plane retardation of the stretched resin layer when the laminate 10 is free-end uniaxially stretched 6.0 times at a temperature condition of 50° C. to 120° C. to form a stretched laminate, and the resin layer in the laminate is thereby formed into a stretched resin layer, i.e., a stretched product of the resin layer. In other words, Re2 is not the retardation of the resin layer itself in the laminate, but is the retardation generated in the stretched product of the resin layer after the laminate is subjected to a specific stretching treatment.
The stretching temperature for obtaining such a stretched product may be any temperature within the range of 50° C. to 120° C. Therefore, a plurality of operation conditions for the stretching to obtain a stretched product are conceivable. When the stretched product exhibits a retardation of 0 nm or more and 20 nm or less under any one of the plurality of operation conditions, the laminate satisfies the above requirement.
However, it is preferable that the stretched product exhibits a retardation of 0 nm or more and 20 nm or less under all of the above-mentioned multiple possible operating conditions. In that case, in the production of a polarizing plate using the laminate for polarizing plate of the present invention, a high degree of freedom in setting the stretching conditions can be obtained.
Generally, in the temperature range, a larger retardation is exhibited when the stretching temperature is lower. Therefore, if the retardation of the stretched product by stretching at 50° C. and the retardation of the stretched product by stretching at 120° C. are both within the range of 0 nm to 20 nm, it can be determined that the stretched product exhibits a retardation of 0 nm to 20 nm under all of the above-mentioned multiple operating conditions.

[2. Manufacturing method of laminate]
The manufacturing method of the laminate according to this embodiment includes, in this order, a first step of stretching an original film containing a polarizer material to obtain a polarizer material film, a second step of applying a resin to one surface of the polarizer material film to form a coating layer, and a third step of drying the coating layer formed in the second step.

The method for manufacturing the laminate may also include a fourth step of activating the surface of the polarizer material film before the second step.

[Laminate manufacturing apparatus]
2 is a schematic diagram showing an example of a manufacturing apparatus 200 used in the laminate manufacturing method according to the present embodiment. The manufacturing apparatus 200 includes a payout device 201, a coating device 202, a winding device 203, a stretching device 204, a treatment device 205 that performs an activation treatment, and a drying device 206. A1 indicates the conveying direction.

[Method of manufacturing laminate]
As shown in Fig. 2, the raw film 1 unwound from the unwinding device 201 is transported to the stretching device 204, where it is stretched to obtain a polarizer material film 11 (first step). The polarizer material film 11 is transported to the processing device 205, where it is activated (fourth step), and then a coating layer is formed in the coating device 202 (second step), and the laminate 10 is obtained through a drying step (third step) in the drying device 206. The laminate 10 thus produced is wound up by the winding device 203, formed into a roll, and can be subjected to further steps. Each step will be described below.

[First step]
The first step is a step of stretching a raw film containing a polarizer material to obtain a polarizer material film.

The stretching process of the raw film in the first step is preferably carried out under the conditions and method (stretching process method, stretching mode, stretching ratio, stretching temperature) described in the section [Polarizer material film] of [1. Laminate]. Specifically, it is preferable that the stretching ratio of the raw film in the first step is X times, and X satisfies 1.5≦X≦5.5. A more preferred range of X is as described in the section [Polarizer material film] of [1. Laminate].

[Second step]
The second step is a step of forming a coating layer by applying a resin to one surface of the polarizer material film 11. The method for applying a resin to the polarizer material film 11 (coating method) is not particularly limited, but is preferably at least one method selected from, for example, solution coating, emulsion coating, and melt extrusion coating, and solution coating is more preferable because it allows high-speed coating and can provide a resin layer with a uniform thickness.

When forming a coating layer by solution coating, the resin used to form the coating layer and any other components added as necessary are dissolved in a solvent to form a resin composition, and the resin composition is applied to the polarizer material film 11. In other words, the phrase "applying a resin" encompasses both the application of only a resin and the application of a resin composition containing a resin and other components.

[Third step]
The third step is a step of drying the coating layer formed in the second step. By carrying out the third step, a resin layer 12 is formed on one surface of the polarizer material film 11.
In the third step, the coating layer is preferably dried for 0.5 to 10 minutes in a dryer at a temperature of 50° C. to 120° C. The drying temperature for the coating layer is more preferably 60° C. or higher, even more preferably 70° C. or higher, and more preferably 100° C. or lower, even more preferably 90° C. or lower. By setting the drying temperature to the lower limit or higher, the drying time can be shortened, and by setting the drying temperature to the upper limit or lower, crystallization of the polarizer material film can be suppressed.

[Fourth step]
The fourth step is a step of activating the surface of the polarizer material film before the second step. In the present invention, the fourth step is an optional step, and the manufacturing method of the present invention may or may not include the fourth step. In the fourth step, by activating the surface of the polarizer material film, plasticizers and the like that have bled onto the polarizer material film surface can be removed, and the polarizer material film surface can be oxidized to increase the adhesion of the resin layer, thereby suppressing peeling of the resin layer when the resin layer is provided.

Activation treatment methods include, for example, corona treatment, plasma treatment, saponification treatment, primer treatment, anchor coating treatment, etc.

There is no limitation on the timing of performing the fourth step, so long as it is performed before the second step. When the heat treatment step described below is performed, the fourth step may be performed before the heat treatment step, after the heat treatment step, or simultaneously with the heat treatment step. Since the heat treatment step may cause plasticizers and the like contained in the polarizer material film to bleed onto the surface of the polarizer material film, it is particularly preferable to perform the fourth step after the heat treatment step.

[Heat treatment process]
The heat treatment step is a step of heat treating the polarizer material film before the second step. In the present invention, the heat treatment step is an optional step, and the manufacturing method of the present invention may or may not include a heat treatment step. By heat treating the polarizer material film in the heat treatment step, wrinkles present in the polarizer material film can be removed and flatness can be improved. By smoothing the polarizer material film, the film thickness accuracy of the resin layer formed in the second step can be improved. The heating temperature of the polarizer material film is preferably 50°C or higher, more preferably 60°C or higher, and preferably 100°C or lower, more preferably 90°C or lower.

[Applications of the laminate]
The laminate 10 of the present invention is a material for manufacturing a polarizing plate. The laminate can be made into a polarizing plate after being subjected to processes such as stretching and dyeing. When the laminate 10 is used as a material for a polarizing plate, the laminate taken up by the winding device 203 shown in FIG. 2 may be used as it is, or a separator film may be laminated on the resin layer 12 of the laminate taken up by the winding device 203, and the laminate may be taken up in a roll shape to form a laminate film roll and then used. Hereinafter, the polarizing plate of this embodiment using the laminate 10 of this embodiment will be described.

[3. Polarizing Plate]
[overview]
The polarizing plate of the present invention can be obtained by uniaxially stretching the laminate of the present invention. Fig. 3 is a schematic diagram showing an example of a manufacturing apparatus for manufacturing a polarizing plate using the laminate of the present embodiment. Fig. 4 is a cross-sectional diagram showing a polarizing plate manufactured using the laminate of the present embodiment.

[Polarizer]
The polarizing plate 100 of this embodiment is a polarizing plate obtained by uniaxially stretching the laminate of this embodiment. As shown in Fig. 4, in the polarizing plate 100, a resin layer 112 is laminated on one surface (the upper surface in the figure) of a polarizer material film 111.

[Characteristics of each layer in the polarizing plate]
The thickness of the polarizer material film 111 in the polarizing plate 100 is preferably 30 μm or less, more preferably 20 μm or less, and preferably 3 μm or more, and more preferably 5 μm or more. When the thickness is equal to or less than the upper limit, the thickness of the polarizing plate can be reduced, and when the thickness is equal to or more than the lower limit, a polarizing plate having a sufficiently high degree of polarization can be obtained.

The in-plane retardation of the resin layer in the polarizing plate is preferably 20 nm or less, more preferably 15 nm or less, even more preferably 10 nm or less, and preferably 0 nm or more. By having the in-plane retardation of the resin layer in the polarizing plate within the above range, black color shift can be suppressed when the polarizing plate is mounted on a liquid crystal display device.

[4. Manufacturing method of polarizing plate]
[overview]
The method for producing a polarizing plate of the present invention is a method for producing a polarizing plate using the laminate of the present invention or a laminate obtained by the method for producing a laminate of the present invention. The method for producing a polarizing plate of the present invention includes a fifth step of dyeing the laminate with a dichroic dye and a sixth step of uniaxially stretching the laminate. That is, the method for producing a polarizing plate of the present invention includes a step of producing the laminate of the present invention by any method or a step of producing a laminate by the method for producing a laminate of the present invention, a fifth step of dyeing the laminate with a dichroic dye, and a sixth step of uniaxially stretching the laminate.
The method for producing a polarizing plate of the present invention may further include a seventh step of laminating a protective film to one or both of the surface of the laminate on the polarizer material film side and the surface of the laminate on the resin layer side after the fifth step, the sixth step, or both of them. The seventh step is an optional step, and in this embodiment, an example of producing a polarizing plate by a production method that does not include the seventh step will be described.

[Polarizing plate manufacturing device]
As shown in FIG. 3, a manufacturing apparatus 300 for manufacturing a polarizing plate includes pay-out devices 301 and 307 , processing devices 302 to 305 , a drying device 306 , a laminating device 308 , and a winding device 310 .

[Method of manufacturing polarizing plate]
In this embodiment, the laminate 10 fed from the feed device 301 is transported to processing devices 302 to 305, where a dyeing process (fifth step) in which the laminate 10 is dyed with a dichroic dye and a stretching process (sixth step) in which the laminate is uniaxially stretched are performed. The laminate after these processes is then dried in a drying device 306 (drying step), to obtain the polarizing plate 100. Each step will be described in detail below.

[Fifth step]
The fifth step is a step of dyeing the laminate 10 with a dichroic dye. In this embodiment, the polarizer material film of the laminate is dyed in the fifth step. In the present invention, it is preferable that the polarizer material film included in the laminate to be subjected to the fifth step is undyed, but the dyeing of the polarizer material film may be performed on the polarizer material film before the laminate is formed.

Examples of the dichroic dye (dichroic substance) used to dye the laminate in the fifth step include iodine and organic dyes. Any dyeing method may be used using these dichroic dyes. For example, dyeing may be performed by immersing a layer of the polarizer material film in a dyeing solution containing the dichroic dye. When iodine is used as the dichroic dye, the dyeing solution may contain an iodide such as potassium iodide in order to increase the dyeing efficiency. There are no particular limitations on the dichroic dye, but when the polarizing plate is used in an in-vehicle display device, an organic dye is preferred as the dichroic dye.

[Sixth step]
The sixth step is a step of uniaxially stretching the laminate. The method of stretching the laminate is not particularly limited, but wet stretching is preferred. The sixth step may be performed before the fifth step, after the fifth step, or simultaneously with the fifth step. The sixth step may be divided and performed multiple times before the fifth step, after the fifth step, or simultaneously with the fifth step. The stretching step may be performed once or more than once.

In the sixth step, the stretching ratio of the laminate is Z times, and Z can be 1.2≦Z≦5.0. Z is preferably 1.2 or more, more preferably 1.5 or more, and preferably 5.0 or less, more preferably 4.0 or less. When the stretching ratio of the laminate is set to the upper limit value of the above range or less, the expression of the phase difference of the resin layer can be reduced and the occurrence of breakage of the polarizing plate can be prevented even after the polarizing plate manufacturing process including the stretching treatment, and when the stretching ratio is set to the lower limit value of the above range or more, a polarizing plate with sufficient polarizing performance can be obtained. When the laminate is stretched two or more times, it is preferable that the total stretching ratio represented by the product of the stretching ratios of each time is set to be in the above range.

It is preferable that the stretching ratio X of the raw film in the first step and the stretching ratio Z of the laminate in the sixth step satisfy 5.1≦X*Y≦9.0. X*Y is the product of X and Y (product of stretching ratios). X*Y is preferably 5.1 or more, more preferably 5.5 or more, and preferably 9.0 or less, more preferably 7.0 or less. By making X*Y equal to or less than the upper limit of the above range, it is possible to reduce the expression of the phase difference of the resin layer and prevent the occurrence of breakage of the polarizing plate even after the polarizing plate manufacturing process including the stretching treatment is performed. By making X*Y equal to or more than the lower limit of the above range, it is possible to obtain a polarizing plate with sufficient polarization performance.

The stretching temperature of the laminate is not particularly limited, but is preferably 30°C or higher, more preferably 40°C or higher, particularly preferably 50°C or higher, and is preferably 140°C or lower, more preferably 90°C or lower, particularly preferably 70°C or lower. When the stretching temperature is equal to or higher than the lower limit of the above range, stretching can be performed smoothly, and when the stretching temperature is equal to or lower than the upper limit of the above range, effective orientation can be achieved by stretching. The above stretching temperature range is preferable for both dry stretching and wet stretching, but is particularly preferable for wet stretching.

The stretching process for the laminate may be any of the following: longitudinal stretching in the longitudinal direction of the film, transverse stretching in the width direction of the film, and oblique stretching in an oblique direction that is neither parallel nor perpendicular to the width direction of the film. The stretching process for the laminate is preferably free-end uniaxial stretching, and more preferably free-end uniaxial stretching in the longitudinal direction.

[Drying process]
The drying step is a step of drying the laminate that has been through the fifth and sixth steps. In the present invention, the drying step is an optional step. In the drying step, the laminate is preferably dried for 0.5 to 10 minutes in a dryer at a temperature of 50° C. to 100° C. The drying temperature of the laminate is more preferably 60° C. or higher, and more preferably 90° C. or lower. By setting the drying temperature to the lower limit or higher, the drying time can be shortened, and by setting the drying temperature to the upper limit or lower, cracking of the polarizer material film can be prevented. The drying time of the laminate is more preferably 1 minute or higher, and more preferably 5 minutes or lower. By setting the drying time to the lower limit or higher, the drying of the laminate is sufficient, and by setting the drying time to the upper limit or lower, cracking of the polarizer material film in the laminate can be prevented.

Conventional thin film polarizers made only of PVA resin could sometimes crack after the drying process, but the polarizing plate of this embodiment is manufactured using a laminate having a polarizer material film and a resin layer laminated directly onto the polarizer material film, so that cracks in the polarizer can be suppressed even after the drying process.

5. Effects and Advantages of the Present Embodiment
In this embodiment, a polarizing plate is manufactured by stretching a laminate having a polarizing material film having a predetermined retardation Re1 and a small thickness T1 and a resin layer provided directly on the polarizing material film, so that the stretching ratio when the laminate is stretched to manufacture a polarizing plate can be reduced. This makes it possible to suppress the occurrence of retardation in the resin layer after the laminate is stretched. As a result, according to this embodiment, the resin layer can be used as it is as a protective film on one side of the polarizing material film without peeling it off, and the amount of wasted material can be reduced, so that the resin layer can be used as a protective film, and a laminate for polarizing plate and a manufacturing method thereof that can be efficiently manufactured even if the thickness is thin, a polarizing plate using the laminate and a manufacturing method thereof, and a manufacturing method of a display device using the polarizing plate can be provided.

In addition, in the laminate 10 of this embodiment, the resin layer 12 is provided directly on the polarizer material film 11 without the use of an adhesive or the like, so that it is possible to prevent the occurrence of wrinkles and voids due to penetration of the adhesive or the like. As a result, according to this embodiment, it is possible to provide a laminate and a manufacturing method thereof, a polarizing plate and a manufacturing method thereof, and a manufacturing method of a display device, which prevent the occurrence of wrinkles and voids.

Furthermore, according to this embodiment, since no other materials are interposed between the resin layer 12 and the polarizer material film 11, it has an excellent breakage suppression effect and can prevent environmental pollution by other substances in the production environment and contamination (mixing of foreign matter) into the product.

[Embodiment 2: Polarizing plate and method for producing the same]
A polarizing plate 120 according to embodiment 2 and a method for manufacturing the same will be described below with reference to Fig. 3 and Fig. 5. The polarizing plate 120 according to this embodiment is manufactured using the polarizing plate 100 according to embodiment 1. The same reference numerals are used to designate the same configurations and aspects as those in embodiment 1, and duplicated descriptions will be omitted.

[Polarizer]
5 is a cross-sectional view showing a polarizing plate 120 according to embodiment 2 of the present invention. In this polarizing plate 120, as shown in FIG. 5, a resin layer 112 is laminated on one surface (the upper surface in the figure) of a polarizer material film 111, and a protective film 115 is laminated on the other surface (the lower surface in the figure) of the polarizer material film 111.

[Method of manufacturing polarizing plate]
The method for producing the polarizing plate 120 of this embodiment includes a seventh step of laminating a protective film on the surface of the laminate on the polarizing material film side after the fifth step and the sixth step. This will be described in detail below.

In the manufacturing method of the polarizing plate 120 of this embodiment, a dyeing process (fifth step) for dyeing the polarizer material film 11 of the laminate 10 and a stretching process (sixth step) for uniaxially stretching the laminate are performed, followed by drying in a drying device 306 to obtain a polarizing plate 100.

3, the polarizing plate 120 is obtained by transporting the polarizing plate 100 obtained through the dyeing process (fifth step) and the stretching process (sixth step) to a lamination device 308, and laminating the protective film 115 unwound from a winding device 307 to the surface of the laminate facing the polarizer material film (seventh step). The obtained polarizing plate 120 is wound up by a winding device 310 into a roll shape, and can be subjected to further processes.

The protective film 115 used in the seventh step may be a film made of one or more resins selected from cycloolefin resin, acrylic resin, polyethylene terephthalate resin, and triacetyl cellulose resin.

The bonding of the protective film 115 to the polarizing plate 100 is not particularly limited and may be performed by a method such as thermocompression bonding (see FIG. 5). The bonding of the protective film 115 to the polarizing plate 100 may be performed via an adhesive or a pressure sensitive adhesive. In the polarizing plate after the fifth and sixth steps, the polarizer material film is hardened, so that the problem of wrinkles caused by penetration of an adhesive or the like is unlikely to occur.
Examples of adhesives and pressure-sensitive adhesives used to bond the protective film to the polarizing plate include acrylic adhesives, epoxy adhesives, urethane adhesives, polyester adhesives, polyvinyl alcohol adhesives, polyolefin adhesives, modified polyolefin adhesives, polyvinyl alkyl ether adhesives, rubber adhesives, vinyl chloride-vinyl acetate adhesives, SEBS (styrene-ethylene-butylene-styrene copolymer) adhesives, ethylene adhesives such as ethylene-styrene copolymers, and acrylic ester adhesives such as ethylene-methyl (meth)acrylate copolymers and ethylene-ethyl (meth)acrylate copolymers.

Like the polarizing plate of embodiment 1, the polarizing plate 120 of this embodiment is manufactured by stretching a laminate having a polarizing material film and a resin layer laminated directly on the surface of the polarizing material film, and therefore has the same effect as embodiment 1.

In addition, according to this embodiment, a protective film 115 is provided on the side of the polarizer material film 111 that is not laminated with the resin layer 112, which also has the effect of preventing scratches, etc. on the surface of the polarizer material film 111.

[Outline of the manufacturing method of the display device of the present invention]
A polarizing plate produced using the laminate of the present invention can be used as a material for displays such as liquid crystal displays, organic EL displays, inorganic EL displays, and micro LED displays.
The method for producing a display device of the present invention is a method for producing a display device using the polarizing plate obtained by the method for producing a polarizing plate of the present invention, and includes an eighth step of laminating the polarizing plate onto a panel. In the method for producing a polarizing plate of the present invention, the panel is a panel selected from a liquid crystal panel, an organic EL panel, and a micro LED panel.

[Embodiment 3: Manufacturing method of display device]
A display device 400 according to a third embodiment, which includes a polarizing plate 100 manufactured using the laminate 10 of the first embodiment, will be described below with reference to FIGS.

The manufacturing method of the display device of this embodiment includes a step (eighth step) of laminating the polarizing plate 100 shown in Figure 4 onto a panel. In this embodiment, an example of manufacturing a liquid crystal display device using a liquid crystal panel as the panel will be described.

Typically, a liquid crystal display device comprises a light source, a light source side polarizing plate, a liquid crystal cell, and a viewer side polarizing plate, in that order. The polarizing plate obtained by the present invention can be used as the light source side polarizing plate, the viewer side polarizing plate, or both.

In this embodiment, in the eighth step, a liquid crystal display device is manufactured by laminating the polarizing plate 100 to a liquid crystal panel as a light source side polarizing plate and a viewer side polarizing plate, respectively.

Figure 6 is a cross-sectional view showing a schematic diagram of a display device manufactured by the manufacturing method of a display device according to embodiment 3 of the present invention. As shown in Figure 6, the display device 400 has two substrates 410, 420, a liquid crystal layer 430 located therebetween, and polarizing plates 100, 100 arranged on the outer sides of the two substrates 410, 420, respectively. The two polarizing plates 100 are polarizing plates 100 manufactured using the laminate 10 of embodiment 1. As shown in Figure 6, the two polarizing plates 100 are laminated such that the resin layer 112 of the polarizing plate is arranged between the polarizer material film 111 of the polarizing plate and the liquid crystal layer 430 of the polarizing plate.

According to this embodiment, the resin layer can also be used as a protective film, and a display device can be provided that includes a polarizing plate that can be efficiently manufactured even with a thin thickness and prevents the occurrence of wrinkles and voids.

[Embodiment 4: Manufacturing method of display device]
A display device 500 according to a fourth embodiment, which includes the polarizing plate 120 manufactured in the second embodiment, will be described below with reference to FIGS.

The manufacturing method of the display device of this embodiment includes a step (eighth step) of laminating a polarizing plate 120 shown in Figure 5 onto a panel. In this embodiment, an example of manufacturing an organic EL display device using an organic EL panel as the panel will be described.

Generally, an organic EL display device comprises, in this order from the light-emitting side, a substrate, a transparent electrode, a light-emitting layer, and a metal electrode layer, and the polarizing plate obtained by the manufacturing method of the present invention is disposed on the light-emitting side of the substrate.
Typically, an organic EL display device has two substrates, a light-emitting layer disposed between them, and a polarizing plate disposed on the outer side of one of the two substrates. The organic EL display device can be manufactured by providing an organic EL panel with the polarizing plate of the present invention.

In this embodiment, in the eighth step, an organic EL display device is manufactured by laminating a polarizing plate 120 onto an organic EL panel.

Figure 7 is a cross-sectional view showing a schematic diagram of a display device manufactured by the manufacturing method of a display device according to embodiment 4 of the present invention. As shown in Figure 7, the display device 500 has two substrates 510, 520, a light-emitting layer 530 located therebetween, and a polarizing plate 120 arranged on the outside (lower side in the figure) of the lower substrate 510. The polarizing plate 120 is the polarizing plate 120 of embodiment 2 manufactured using the laminate 10. As shown in Figure 7, the polarizing plate 120 is laminated such that the resin layer 112 of the polarizing plate is arranged between the polarizer material film 111 of the polarizing plate and the light-emitting layer 530.

According to this embodiment, the resin layer can also be used as a protective film, and a display device can be provided that is equipped with a polarizing plate that can be efficiently manufactured even with a thin thickness and prevents the occurrence of wrinkles and voids.

[Other embodiments]
(1) In embodiment 2, an example is shown in which a protective film is attached only to the surface of the laminate facing the polarizer material film. However, a protective film may be attached only to the surface of the laminate facing the resin layer, or a protective film may be attached to both the surface of the laminate facing the polarizer material film and the surface of the laminate facing the resin layer.

(2) In embodiments 3 and 4, examples are shown in which the panels are liquid crystal panels and organic EL panels, but the panel on which the polarizing plate is laminated may also be a micro LED panel.

(3) In the third embodiment, a method for manufacturing a liquid crystal display device in which two polarizing plates 100 described in the first embodiment are stacked is described, but the present invention is not limited to this. Two polarizing plates 120 described in the second embodiment may be stacked, two types of polarizing plates may be stacked, or one polarizing plate may be stacked.

(4) In embodiment 4, a manufacturing method for an organic EL display device in which the polarizing plate 120 of embodiment 2 is laminated is shown, but polarizing plate 100 may be used instead of polarizing plate 120.

The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following, "parts" and "%" regarding the ratio of components represent parts by weight unless otherwise specified.

[Evaluation method]
[Weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn)]
The molecular weights of the block copolymer and the hydrogenated block copolymer were measured in terms of standard polystyrene by GPC using THF as an eluent at 38° C. The measuring device used was an HLC8020GPC manufactured by Tosoh Corporation.

[Hydrogenation rate]
The hydrogenation rate of the hydrogenated block copolymer was calculated by ¹ H-NMR spectrum or GPC analysis. The region with a hydrogenation rate of 99% or less was calculated by measuring the ¹ H-NMR spectrum, and the region with a hydrogenation rate of more than 99% was calculated from the ratio of peak areas measured by a UV detector and an RI detector using GPC analysis.

[Measurement of MFR (Melt Flow Rate Measured at 190°C and a Load of 2.16 kg)]
The film-forming coating solution used in each example was applied to a separator film ("MRV38" manufactured by Mitsubishi Chemical Corporation) using a die coater, and dried to form a film containing polymer X having a thickness of 10 μm. The film containing polymer X was peeled off from the separator film to obtain a sample film. The MFR of this sample film was measured by the following method.
The MFR was measured in accordance with JIS K7210 using an extrusion-type plastometer (trade name "Melt Indexer (L240)" manufactured by Tateyama Scientific Industrial Co., Ltd.) at a temperature of 190° C. and a load of 2.16 kg.

[Measurement of tensile modulus]
The tensile modulus of elasticity was measured using a sample film prepared in the same manner as the "sample film" described in the section "Measurement of MFR".
The tensile modulus was measured by the following method based on JIS K7127 using a tensile tester (manufactured by Instron Japan Company Limited, trade name "Electromechanical Universal Material Tester (5564)").
The sample film was punched out into the shape of a test piece type 1B described in JIS K7127, and the stress was measured when the test piece was pulled in the long side direction to cause distortion. The stress measurement conditions were a temperature of 23°C, a humidity of 60±5% RH, a chuck distance of 115 mm, and a pulling speed of 50 mm/min. The stress measurement was performed five times. From the measured stress and the measurement data of the strain corresponding to the stress, four measurement data points were selected at intervals of 0.2% in the range of the strain of the test piece from 0.6% to 1.2% (i.e., measurement data when the strain was 0.6%, 0.8%, 1.0%, and 1.2%), and the tensile modulus was calculated from the four measurement data points (total of 20 points) of the five measurements using the least squares method.

[Method of measuring phase difference]
The in-plane retardation Re1 and the in-plane retardation Re2 of the polarizer material film and the in-plane retardation of the resin layer in the polarizing plate were measured using a retardation meter (Muller matrix polarimeter, product name "Axo Scan", manufactured by Optoscience Co., Ltd.) at a measurement wavelength of 550 nm.
The retardation Re2 was measured by measuring the in-plane retardation of the stretched resin layer, i.e., the resin layer obtained by stretching the laminate to 6.0 times the free end uniaxially at a predetermined temperature (50 ° C. and 120 ° C.). In the present application, if the in-plane retardation of the resin layer generated when the laminate is stretched to 6.0 times the free end uniaxially at a temperature condition of 50 ° C. and the in-plane retardation of the resin layer generated when the laminate is stretched to 6.0 times the free end uniaxially at a temperature condition of 120 ° C. are both within the range of 0 nm to 20 nm, the retardation Re2 in the in-plane direction of the resin layer generated when the laminate is stretched to 6.0 times the free end uniaxially at a temperature condition of 50 ° C. to 120 ° C. was determined to be 0 nm to 20 nm.

[Thickness measurement method]
The thickness of each film (polarizer material film and resin layer) included in the laminate and the thickness of each film included in the polarizing plate were measured five times using a thickness meter (manufactured by Mitutoyo Corporation, product name "ABS Digimatic Thickness Gauge (547-401)"), and the average value was taken as the thickness of each film.

[Evaluation of Surface Condition of Polarizing Plate]
The surface of the polarizing plate of each example was visually observed, and the number of wrinkles and voids per 10 cm square was measured. The measurement was performed at five points on the polarizing plate, and the average value was calculated and evaluated according to the following evaluation criteria.
A: No wrinkles or voids are observed.
B: The number of wrinkles is 1 or more and 3 or less, or the number of voids is 1 or more and less than 10.
C: The number of wrinkles is 4 or more, or the number of voids is 10 or more.

[Evaluation of Adhesion]
In the processes up to the second stretching treatment in the manufacture of each polarizing plate, those in which no peeling occurred between the polarizing material film and the resin layer were rated A, those in which partial peeling was observed were rated B, and those in which complete peeling occurred were rated C.

[Evaluation of drying processability]
In the manufacturing process of the polarizing plate of each example, a polarizer in which no cracks were generated during the drying process at 70° C. for 5 minutes was rated as A, and a polarizer in which cracks were generated was rated as C.

[Black color shift]
The liquid crystal display panel was removed from a liquid crystal display device (manufactured by LG Electronics Japan, product name "IPS Panel Monitor (23MP47)"), the polarizing plate arranged on the viewing side was peeled off, and the polarizing plate prepared in the Examples and Comparative Examples was attached so that the resin layer was on the panel side. In addition, a polarizer without a protective film was attached next to the polarizing plate prepared in the Examples and Comparative Examples, and the liquid crystal display device was reassembled. The polarizing plates prepared in the Examples and Comparative Examples and the polarizer without a protective film were attached so that the absorption axis of the polarizing plate before peeling was in the same direction as the absorption axis of the polarizing plate before peeling.
When the direction of the absorption axis of the polarizing plate arranged on the viewing side was set to an azimuth angle of 0° and the vertical direction of the panel was set to a polar angle of 0°, the panel was set to a black display state (i.e., a state in which black was displayed across the entire display screen of the panel), and when visually observed from an azimuth angle of 45° and a polar angle of 45°, those that showed the same color change as in the case of a polarizer without a protective film were rated as A, those that showed a slight color change were rated as B, and those that showed a large change were rated as C.

[Example 1]
(1-1) Production of Polarizer Material Film An unstretched polyvinyl alcohol film (average polymerization degree: about 2400, saponification degree: 99.9 mol %, thickness: 20 μm, hereinafter also referred to as “PVA20”) was used as an original film.
The raw film was dry-stretched in the machine direction at a stretching temperature of 130° C. and a stretching ratio of 1.5 times (X=1.5) using a longitudinal uniaxial stretching machine to obtain a polarizer material film. The polarizer material film had a thickness T1 of 16 μm and an Re1 of 320 nm.

(1-2) Preparation of Polymer X Referring to the production example described in JP 2002-105151 A, 25 parts of styrene monomer were polymerized in the first stage, 30 parts of styrene monomer and 25 parts of isoprene monomer were polymerized in the second stage, and then 20 parts of styrene monomer were polymerized in the third stage to obtain a block copolymer [D1], which was then hydrogenated to synthesize a hydrogenated block copolymer [E1]. The hydrogenated block copolymer [E1] had an Mw of 84,500, an Mw/Mn of 1.20, and a hydrogenation rate of the main chain and aromatic ring of approximately 100%.
100 parts of the hydrogenated block copolymer [E1] was mixed with 0.1 part of pentaerythrityl tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] (manufactured by Matsubara Sangyo Co., Ltd., product name "Songnox 1010") as an antioxidant by melt kneading, and then pelletized to obtain a polymer X for molding.

(1-3) Production of Laminate The polymer X produced in (1-2) was dissolved in cyclohexane, and then 40 parts by weight of polyisobutene ("Nippon Oil Polybutene HV-300", number average molecular weight 1,400, manufactured by JX Nippon Oil & Energy Corporation) and 0.1 parts by weight of an organosilicon compound (3-aminopropyltriethoxysilane, KBM903, manufactured by Shin-Etsu Chemical Co., Ltd.) were added relative to 100 parts by weight of polymer X to prepare a film-forming coating solution A (resin composition A).
The obtained coating solution A for film formation was applied to one surface of the polarizer material film produced in (1-1) using a die coater, and then dried, thereby obtaining a long laminate composed of the polarizer material film and a resin layer (width 600 mm, thickness 10 μm) containing polymer X.
In the obtained laminate, the thickness of the resin layer, the thickness T1 of the polarizer material film, and the in-plane retardation Re1 and retardation Re2 (temperature conditions: 50°C, 120°C) were measured. In addition, the MFR and tensile modulus of the resin constituting the resin layer were measured by the method described in the evaluation method. The results are shown in Table 1.

(1-4) Production of Polarizing Plate The laminate produced in (1-3) was continuously transported in the longitudinal direction via guide rolls, while the following operations were carried out.
The laminate was subjected to a swelling treatment of immersing in water, a dyeing treatment of immersing in a dyeing solution containing iodine and potassium iodide, and a first stretching treatment of stretching the laminate after the dyeing treatment. Next, the laminate after the first stretching treatment was subjected to a second stretching treatment of stretching in a bath containing boric acid and potassium iodide. The total stretching ratio, which is the product of the stretching ratio in the first stretching treatment and the stretching ratio in the second stretching treatment, was set to 4.0 times (Z = 4.0). The stretching temperature was set to 57 ° C. The laminate after the second stretching treatment was dried in a dryer at 70 ° C. for 5 minutes (drying step) to obtain a polarizing plate.
The adhesion was evaluated in the process up to the second stretching treatment, the drying processability was evaluated in the drying process, and the obtained polarizing plate was evaluated for surface condition and black color shift. The evaluation results are shown in Table 1.
In addition, the thickness and retardation of the resin layer of the obtained polarizing plate, and the thickness of the polarizing material film were measured. The measurement results are shown in Table 1.

[Example 2]
Except for the fact that the stretching ratio of the raw film was 5.5 times (X=5.5) and the stretching ratio of the laminate was 1.2 times (Z=1.2), the same operations as in Example 1 were carried out to produce a laminate and a polarizing plate, and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 1.

[Example 3]
The stretching ratio of the raw film was 2.0 times (X = 2.0), the coating amount was adjusted when coating and drying the film-forming coating solution A in (1-3) of Example 1 to provide a resin layer with a thickness of 5 μm (width was the same as in Example 1), and the stretching ratio of the laminate was 3.0 times (Z = 3.0). Except for this, the same operations as in Example 1 were carried out to produce a laminate and a polarizing plate, and evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[Example 4]
Except for the fact that the stretching ratio of the raw film was 3.0 times (X=3.0) and the stretching ratio of the laminate was 2.0 times (Z=2.0), the same operations as in Example 1 were carried out to produce a laminate and a polarizing plate, which were then evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 5]
Except for the fact that the stretching ratio of the raw film was 3.0 times (X = 3.0), that the film-forming coating solution B was used instead of the film-forming coating solution A, and that the stretching ratio of the laminate was 2.0 times (Z = 2.0), the same operations as in Example 1 were carried out to produce a laminate and a polarizing plate, and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 1.

Coating solution B for film formation was prepared by the following method.
The polymer X produced in (1-2) of Example 1 was dissolved in cyclohexane, and then 0.1 part by weight of an organosilicon compound (3-aminopropyltriethoxysilane, KBM903, manufactured by Shin-Etsu Chemical Co., Ltd.) was added to 100 parts by weight of the polymer X to prepare a film-forming coating solution B (resin composition B).

[Example 6]
Except for the fact that the stretching ratio of the raw film was 3.0 times (X = 3.0), that the film-forming coating solution C was used instead of the film-forming coating solution A, and that the stretching ratio of the laminate was 2.0 times (Z = 2.0), the same operations as in Example 1 were carried out to produce a laminate and a polarizing plate, and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

The film-forming coating solution C was prepared by the following method.
The polymer X produced in Example 1 (1-2) was dissolved in cyclohexane, and then 40 parts by weight of polyisobutene ("Nippon Oil Polybutene HV-300", number average molecular weight 1,400, manufactured by JX Nippon Oil & Energy Corporation) and 0.1 parts by weight of an organic titanium compound (tetraisopropyl titanate, Orgatix TA-8, manufactured by Matsumoto Fine Chemical Co., Ltd.) were added relative to 100 parts by weight of the polymer X to prepare a film-forming coating solution C (resin composition C).

[Example 7]
Except for the fact that the stretching ratio of the raw film was 2.0 times (X = 2.0), that the film-forming coating solution D was used instead of the film-forming coating solution A, and that the stretching ratio of the laminate was 3.0 times (Z = 3.0), the same operations as in Example 1 were carried out to produce a laminate and a polarizing plate, and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

The film-forming coating solution D was prepared by the following method.
Polymer X produced in Example 1 (1-2) was dissolved in cyclohexane, and then 40 parts by weight of polyisobutene ("Nippon Oil Polybutene HV-300", number average molecular weight 1,400, manufactured by JX Nippon Oil & Energy Corporation) and 0.1 parts by weight of an organic zirconium compound (normal propyl zirconate, Orgatix ZA-45, manufactured by Matsumoto Fine Chemical Co., Ltd.) were added relative to 100 parts by weight of Polymer X to prepare a film-forming coating solution D (resin composition D).

[Example 8]
Except for using a 45 μm-thick unstretched polyvinyl alcohol film (average polymerization degree about 2400, saponification degree 99.9 mol%, hereinafter also referred to as "PVA45") as the raw film instead of PVA20, and setting the stretching ratio of the raw film to 2.0 times (X=2.0), and setting the stretching ratio of the laminate to 3.0 times (Z=3.0), the same operations as in Example 1 were carried out to produce a laminate and a polarizing plate, and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

[Example 9]
Except for using PVA45 instead of PVA20 as the raw film, setting the stretching ratio of the raw film to 3.0 times (X=3.0), and setting the stretching ratio of the laminate to 2.0 times (Z=2.0), the same operations as in Example 1 were carried out to produce a laminate and a polarizing plate, and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

[Example 10]
Except for using a 60 μm-thick unstretched polyvinyl alcohol film (average polymerization degree: about 2400, saponification degree: 99.9 mol%, hereinafter also referred to as "PVA60") as the raw film instead of PVA20, and setting the stretching ratio of the raw film to 2.0 times (X=2.0), and setting the stretching ratio of the laminate to 3.0 times (Z=3.0), the same operations as in Example 1 were carried out to produce a laminate and a polarizing plate, and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 2.

[Example 11]
Except for the fact that the stretching ratio of the raw film was 3.0 times (X=3.0), that the film-forming coating solution E was used instead of the film-forming coating solution A, and that the stretching ratio Z of the laminate was 2.0, the same operations as in Example 1 were carried out to produce a laminate and a polarizing plate, and evaluations were carried out in the same manner as in Example 1. The results are shown in Table 3.

The film-forming coating solution E was prepared by the following method.
Polymer X produced in Example 1 (1-2) was dissolved in cyclohexane, and then 40 parts by weight of polyisobutene ("Nippon Oil Polybutene HV-300", number average molecular weight 1,400, manufactured by JX Nippon Oil & Energy Corporation) was added per 100 parts by weight of Polymer X to prepare a film-forming coating solution E (resin composition E).

[Comparative Example 1]
In Example 1 (1-4), the laminate produced in (1-3) was replaced with PVA20 (unstretched polyvinyl alcohol resin film), and the same operations as in Example 1 (1-4) were carried out. As a result, melting occurred frequently in the first stretching treatment and the second stretching treatment, and breakage occurred frequently in the drying step, and evaluation of the surface condition, adhesion, and black color shift was not possible.

[Comparative Example 2]
(C2-1) Production of Polarizer Material Film A PVA20 raw film was dry-stretched in the longitudinal direction at a stretching temperature of 130° C. and a stretching ratio of 2.0 times (X=2.0) using a longitudinal uniaxial stretching machine to obtain a polarizer material film. The polarizer material film had a thickness T1 of 14 μm and an Re1 of 350 nm.

(C2-2) Production of Laminate [0123] The film-forming coating solution A prepared in (1-3) of Example 1 was applied to a separator film (manufactured by Mitsubishi Chemical Corporation, "MRV38") using a die coater, followed by drying, to obtain a long film (resin film) containing polymer X having a width of 650 mm, a length of 500 m and a thickness of 10 µm.
An adhesive was obtained by mixing 100 parts by weight of water, 3 parts by weight of a polyvinyl alcohol-based adhesive ("Z-200" manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and 0.3 parts by weight of a crosslinking agent ("SPM-01" manufactured by Nippon Synthetic Chemical Industry Co., Ltd.). This adhesive was applied to one side of the resin film, and the polarizer material film produced in (C2-1) was attached thereto. In this state, the adhesive was heated and dried at 70°C for 5 minutes to obtain a laminate. The obtained laminate was subjected to the same operation as in (1-4) of Example 1 to obtain a polarizing plate. The obtained laminate and polarizing plate were evaluated in the same manner as in Example 1. The results are shown in Table 3.

In the table, "Re2 (50°C)" means the in-plane retardation of the resin layer that occurs when the laminate is free-end uniaxially stretched to 6.0 times at a temperature condition of 50°C, and "Re2 (120°C)" means the in-plane retardation of the resin layer that occurs when the laminate is free-end uniaxially stretched to 6.0 times at a temperature condition of 120°C.
In the table, "Re1" means the retardation in the in-plane direction of the polarizer material film in the laminate.
In the table, "direct coating" indicates that the resin layer was formed by applying a film-forming coating liquid (resin composition) directly to a polarizer material film, and "lamination" indicates that the resin film was laminated to the polarizer material film via an adhesive.
In the table, "polarizer" refers to a polarizer material film in a polarizing plate.

From the results in Tables 1 to 3, it can be seen that according to the present invention, it is possible to reduce the phase difference that appears in the resin layer after the process of stretching the laminate, and to obtain a polarizing plate that is excellent in adhesion, drying processability, and optical properties. It can also be seen that according to the present invention, it is possible to prevent the occurrence of wrinkles and voids. As a result, it can be seen that it is possible to provide a laminate and a manufacturing method thereof in which the resin layer can be used as a protective film and can be efficiently manufactured even if it is thin, and in which the occurrence of wrinkles and voids is prevented, a polarizing plate and a manufacturing method thereof using the laminate, and a manufacturing method for a display device.

1... Raw film 10... Laminate 11... Polarizer material film 12... Resin layer 100, 120... Polarizing plate 111... Polarizer material film 112... Resin layer 115... Protective film 200... Manufacturing device 201... Unwinding device 202... Coating device 203... Winding device 204... Stretching device 205... Activation processing device 206... Drying device 300... Manufacturing device 301, 307... Unwinding devices 302 to 305... Processing device 306... Drying device 308... Bonding device 310... Winding device 400... Display device (liquid crystal display device)
410, 420... Substrate 430... Liquid crystal layer 500... Display device (organic EL display device)
510, 520...substrate 530...light-emitting layer

Claims (7)

A method for producing a polarizing plate, comprising the steps of:
A first step of stretching a raw film containing a polarizer material to obtain a polarizer material film;
a second step of applying a resin to one surface of the polarizer material film to form a coating layer;
a third step of drying the coating layer to obtain a resin layer, and a fifth step of dyeing the laminate with a dichroic dye.
A sixth step of uniaxially stretching the laminate,
the polarizer material film is a polyvinyl alcohol resin film,
The method for producing a polarizing plate, wherein the resin layer is made of a cycloolefin resin. The method for producing a polarizing plate according to claim 1 , wherein the stretching in the first step is performed at a stretching ratio of X times, where X satisfies 1.5≦X≦5.5. The method for producing a polarizing plate according to claim 1 , further comprising a fourth step of activating the surface of the polarizer material film before the second step. The method for producing a polarizing plate according to claim 1 , wherein the stretching ratio in the sixth step is Z times, and Z satisfies 1.2≦Z≦5.0. The method for producing a polarizing plate according to any one of claims 1 to 4 , wherein X and Z satisfy 5.1≦X*Z≦9.0. The method for producing a polarizing plate according to any one of claims 1 to 5, further comprising a seventh step of laminating a protective film to one or both of a surface of the laminate facing the polarizer material film and a surface of the laminate facing the resin layer after the fifth step, the sixth step, or both of these steps. A method of manufacturing a display device, comprising the steps of:
A method for producing a polarizing plate according to any one of claims 1 to 6 , and an eighth step of laminating the polarizing plate on a panel,
The method for manufacturing a display device, wherein the panel is selected from a liquid crystal panel, an organic electroluminescence panel, and a micro LED panel.

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