Polarizing plate and optical display device including the same

Abstract

Disclosed are a polarizing plate and an optical display device including the same. The polarizing plate includes a polarizer and a barrier layer formed on one surface of the polarizer. The barrier layer contains a cured product of a composition containing a polyvinyl alcohol resin, a crosslinking agent, and an aqueous ionic material, and the amount of the aqueous ionic material in the barrier layer is 0.5 wt% to 18 wt% based on a total of 100 wt% of the barrier layer.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2024-0037764 filed in the Korean Intellectual Property Office on March 19, 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to a polarizing plate and an optical display device including the polarizing plate. Background Art

[0004] Although LED displays, including organic LED displays, are not required to include polarizers, such displays can suffer from poor screen quality due to total reflection of external light at the panel surface within the display. Therefore, LED displays typically include a polarizer on the upper surface of the panel. A polarizer includes a polarizer and a retardation film. While the retardation film can be a polymer film, liquid crystal films have recently been used as the retardation film due to the trend toward decreasing polarizer thickness.

[0005] Background art of the present disclosure is disclosed in Korean Patent Laid-Open No. 10-2006-0103451 and the like. Summary of the Invention

[0006] One aspect of an embodiment of the present disclosure relates to a polarizing plate that does not include a protective layer on at least one surface of the polarizer and includes a barrier layer to prevent or reduce elution of a dichroic material from the polarizer when placed under high temperature / humidity conditions for a long time.

[0007] One aspect of the present disclosure relates to a polarizing plate.

[0008] Recently, with the trend of reducing the thickness of polarizing plates, a method of stacking a barrier layer instead of a protective layer on the polarizing plate has been considered. The barrier layer is generally formed by depositing and curing a barrier layer composition, thereby enabling the barrier layer to have a thickness smaller than that of the related art protective layer.

[0009] A polarizing plate according to an embodiment of the present disclosure includes a polarizer and a barrier layer formed on a surface of the polarizer, wherein the barrier layer includes a cured product of a composition containing a polyvinyl alcohol resin, a cross-linking agent, and a water-based ion material, and the amount of the water-based ion material in the barrier layer is 0.5 wt % to 18 wt % based on 100 wt % of the total barrier layer.

[0010] Another aspect of the present disclosure relates to an optical display device.

[0011] The optical display device includes the polarizing plate according to the present disclosure or includes the blocking layer according to the present disclosure.

[0012] Embodiments of the present disclosure provide a polarizing plate that does not include a protective layer on at least one surface of the polarizer and includes a barrier layer to prevent or reduce elution of a dichroic material from the polarizer when placed under high temperature / humidity conditions for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The accompanying drawings are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the disclosure and together with the description serve to explain the principles of the disclosure.

[0014] Figure 1 is a cross-sectional view of a polarizing plate according to one embodiment of the present disclosure.

[0015] Figure 2 is a cross-sectional view of a polarizing plate according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0016] Hereinafter, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings so as to facilitate implementation by those skilled in the art. It should be understood that the present disclosure can be implemented in various ways and is not limited to the following embodiments.

[0017] In the accompanying drawings, for the sake of clarity, parts not related to the present description will not be described in detail, and the same components will be represented by the same reference numerals throughout the specification. The lengths, sizes, etc. of the components in the accompanying drawings are selected for the purpose of illustrating the present disclosure, and the present disclosure is not limited thereto.

[0018] In this document, spatially relative terms such as "upper" and "lower" are defined with reference to the accompanying drawings. Therefore, it should be understood that "upper surface" and "lower surface" can be used interchangeably. In addition, when an element is referred to as being placed "on" another element, the element can be placed directly on the other element, or one or more intervening elements may be present. On the other hand, when an element is referred to as being placed "directly" on another element, there are not one or more intervening elements between the elements.

[0019] The terms used herein are for the purpose of describing example embodiments and are not intended to be limiting of the present disclosure. Unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" as used herein are intended to include the plural forms as well.

[0020] “X to Y” used herein to express a specific numerical range means “greater than or equal to X and less than or equal to Y (X≤ and ≤Y)”.

[0021] The present disclosure relates to a polarizing plate that does not include a protective layer on at least one surface of a polarizer. The polarizing plate includes a barrier layer instead of a protective layer. For example, the polarizing plate may have a barrier layer instead of a protective layer on one surface of the polarizing plate and a protective layer on an opposite surface of the polarizing plate, or both opposite surfaces of the polarizing plate may each have a barrier layer on them instead of a protective layer.

[0022] Here, the term "protective layer" refers to an optical device (e.g., an optical layer) stacked on one surface of a polarizer to protect the polarizer. The protective layer may be a protective film or a protective coating. The protective layer may be a liquid crystal layer or a non-liquid crystal layer. The protective layer may have an in-plane retardation within a predetermined range at a wavelength of 550 nm, or may have no in-plane retardation.

[0023] In one embodiment, the protective film may include a suitable optically transparent protective film or protective coating (e.g., an optically transparent protective film or protective coating known to those skilled in the art). For example, the protective film may include at least one selected from cellulose ester resins (e.g., triacetylcellulose (TAC), etc.), cyclic polyolefin (COP) resins (e.g., amorphous cyclic polyolefins, etc.), polycarbonate resins, polyester resins (e.g., polyethylene terephthalate (PET), etc.), polyethersulfone resins, polysulfone resins, polyamide resins, polyimide resins, non-cyclic polyolefin resins, poly(meth)acrylate resins (e.g., poly(methyl methacrylate)), polyvinyl alcohol resins, polyvinyl chloride resins, and polyvinylidene chloride resins.

[0024] In one embodiment, the barrier layer can be formed directly on the polarizer. Here, "directly formed" means that the barrier layer is formed on the polarizer without any adhesive layer or bonding layer between the polarizer and the barrier layer. For example, the barrier layer can be formed by directly coating or depositing the barrier layer composition described in more detail below on one surface of the polarizer, followed by drying and curing.

[0025] In one embodiment, the polarizing plate may include a polarizer, a protective layer stacked on one surface of the polarizer, and a barrier layer stacked on another surface of the polarizer (e.g., a surface opposite to the surface having the protective layer). For example, the polarizing plate may include a polarizer having a first surface and a second surface opposite to the first surface. The protective layer is stacked on the first surface of the polarizer, and the barrier layer is stacked on the second surface of the polarizer.

[0026] As will be described in more detail below, the barrier layer can be formed by depositing the barrier layer composition onto one surface of the polarizer and then curing it. Therefore, the barrier layer has a thin thickness. The polarizer contains a dichroic material (e.g., iodine and / or similar materials) to provide polarization performance. Therefore, when the polarizer is placed under high temperature / humidity conditions (e.g., high temperature and high humidity) for a long time, the dichroic material (e.g., iodine and / or similar materials) can be eluted from the polarizer (e.g., diffused from the polarizer). The dichroic material eluted from the polarizer can pass through an optical device arranged between the polarizer and the optical display panel to which the polarizer is attached, thereby causing corrosion to the optical display panel (e.g., substrate). The polarizer according to one or more embodiments includes a barrier layer as described in more detail below. When placed under high temperature / humidity conditions for a long time, the polarizer prevents or substantially prevents the dichroic material eluted from the polarizer from passing through the barrier layer, thereby preventing or reducing corrosion to the substrate. Whether the dichroic material eluted from the polarizer has passed through the barrier layer can be checked by color change. An experimental example for examining color changes is described in more detail below.

[0027] Next, a polarizing plate according to one embodiment will be described.

[0028] The polarizing plate according to the embodiment includes a polarizer and a blocking layer formed on one surface of the polarizer.

[0029] barrier layer

[0030] The barrier layer comprises a cured product of a composition comprising a polyvinyl alcohol resin, a crosslinking agent, and a water-based ion material. In addition, the water-based ion material is present in the barrier layer in an amount of 0.5 wt % to 18 wt %.

[0031] The barrier layer comprises a cured product of the composition.

[0032] In one embodiment, the cured product may be a thermally cured product. The barrier layer may be prepared by thermally curing (e.g., heat treating) the composition without light irradiation. Thus, the barrier layer allows an ultraviolet (UV) absorber to be included in any layer of the polarizing plate. For example, using thermal curing as a curing method for the barrier layer allows an ultraviolet absorber to be included in any layer of the polarizing plate without being damaged by the curing process. When the polarizing plate is formed on a light-emitting diode display, the ultraviolet absorber can prevent or reduce damage to the light-emitting diode from external light.

[0033] In one or more embodiments, the barrier layer may include a polyvinyl alcohol resin, a crosslinking agent, and a water-based ion material. These components may be derived from the composition (eg, as thermally cured products of corresponding components of the composition).

[0034] The composition is an aqueous composition and includes a polyvinyl alcohol resin, a cross-linking agent, an aqueous ionic material, and an aqueous solvent. The aqueous ionic material can be easily dissolved in the aqueous solvent to facilitate the formation of a barrier layer and can prevent or substantially prevent the dichroic material eluted from the polarizer located on the front side of the polarizing plate from passing through the barrier layer.

[0035] The water-based ion material is present in the barrier layer in an amount of 0.5% to 18% by weight. When the water-based ion material is present in the barrier layer in an amount of 0.5% by weight or greater, the water-based ion material can prevent or substantially prevent the dichroic material eluted when the polarizing plate is exposed to high temperature / humidity conditions for a long time from passing through the barrier layer, thereby preventing or reducing corrosion of the substrate. When the water-based ion material is present in the barrier layer in an amount of 18% by weight or less, the barrier layer does not suffer from any problems, such as deterioration in light transmittance due to an excess of the water-based ion material, and can be formed on the polarizer with high (e.g., strong) adhesion.For example, the water-based ion material can be 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4 , 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 1 0.6, 10.7, 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, 12.0, 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, 12.9, 13.0, 13.1, 13.2, 13.3, 13.4, 13.5, 13.6, 13.7, 13.8, 13.9, 14.0, 14.1, 14.2, 14.3, 14.4, 14.5, 14.6, 14.7, 14.8 %, 0.9 wt % to 17 wt %, 0.9 wt % to 17 wt %, or 0.9 wt % to 17 wt %.

[0036] The aqueous ionic material not only dissolves well in the aqueous solvent but also, while dissolved in the aqueous solvent, adsorbs the dichroic material (e.g., iodide ions) eluted from the polarizer, thereby preventing (e.g., ultimately preventing) the dichroic material from penetrating into the barrier layer. Since the ionic material is included in the aqueous barrier layer composition, the ionic material should be soluble in the aqueous solvent. Furthermore, it is desirable that the ionic material be able to adsorb the eluted dichroic material, such as iodide ions. Furthermore, it is desirable that the aqueous ionic material not interfere with the curing reaction between the polyvinyl alcohol resin and the crosslinking agent described in more detail below.

[0037] The water-based ionic material includes cations and anions, wherein the cations can adsorb the eluted iodide ions.

[0038] In one embodiment, the aqueous cationic material may include ammonium cations and anions.

[0039] In one embodiment, the ammonium cation may have a hydroxyl group or an aliphatic or aromatic hydrocarbon group substituted with a hydroxyl group. The ammonium cation may promote the adsorption of the eluted dichroic material (e.g., iodide ion). For example, the water-based ionic material may have at least one hydroxyl group, e.g., 1 to 5 hydroxyl groups.

[0040] In one embodiment, the aqueous cationic material may include nitrate anions or sulfate anions. These anions may facilitate the adsorption of the eluted dichroic material (eg, iodide ions).

[0041] For example, the water-based ionic material may include a compound represented by Formula 1:

[0042] R 1 R 2 R 3 R 4 N + X,

[0043] wherein X is a monovalent nitrate anion or a monovalent sulfate anion; and

[0044] R 1 、R 2 、R 3 and R 4 Each independently represents a substituted or unsubstituted linear or branched C1 to C 10 Alkyl or substituted or unsubstituted C6 to C 20 Aryl.

[0045] In Formula 1, the carbon number of the alkyl group refers only to the carbon number of the main chain of the linear or branched alkyl group. In Formula 1, the carbon number of the aryl group refers only to the carbon number of the ring (eg, monocyclic or condensed ring) constituting the aryl group.

[0046] In Formula 1, the "substituted" in the expression "substituted or unsubstituted" means that at least one hydrogen atom of the corresponding functional group is replaced by a linear or branched C1 to C 10 Alkyl, hydroxyl (OH), linear or branched C1 to C 20 The "substituted amide group" herein refers to a functional group represented by Formula 2:

[0047] R 5 -C(=O)-NH-*,

[0048] Where * is the attachment site to the element, and R 5 Is a straight chain or branched C1 to C 20 alkyl.

[0049] In an embodiment, in Formula 2, R 5 Is a straight chain or branched C 10 to C 20 alkyl.

[0050] In an embodiment, R 1 、R 2 、R 3 or R 4 At least one of the C1 to C 10 Alkyl or hydroxy-substituted C6 to C 20 In an embodiment, R 1 、R 2 、R 3 or R 4 At least one of the ionic materials is a C1 to C5 alkyl group substituted with a hydroxyl group. Here, the ionic material may be soluble (eg, well soluble) in the aqueous composition and may facilitate adsorption of the eluted dichroic material.

[0051] In an embodiment, R 1 、R 2 、R 3 or R 4 At least one of them is C1 to C 20 Alkoxy-substituted C1 to C 10 In an embodiment, R 1 、R 2 、R 3 or R 4 At least one of them is C 10 to C 20 Alkoxy-substituted C1 to C5 alkyl.

[0052] In an embodiment, R 1 、R 2 、R 3 or R 4At least one of which is a C1 to C 10 In an embodiment, R 1 、R 2 、R 3 or R 4 At least one of the is a C1 to C5 alkyl group substituted with a substituted amide group.

[0053] In an embodiment, X is NO3 - or R-SO4 - , wherein R is a linear or branched C1 to C5 alkyl group. In an embodiment, X is NO3 - or CH3SO4 - .

[0054] In an embodiment, R 1 、R 2 、R 3 or R 4 At least one of the groups is a long chain alkyl or long chain alkoxy, which may be a straight chain or branched C 10 to C 20 Alkyl or linear or branched C 10 to C 20 Alkoxy substitution.

[0055] For example, the water-based ion material may include at least one compound represented by Formula 1-1 or Formula 1-2:

[0056] Formula 1-1

[0057]

[0058] Formula 1-2

[0059]

[0060] In one embodiment, the water-based ionic material may have a liquid phase or a solid phase (eg, a liquid phase) at room temperature (eg, at 20° C. to 30° C.). For example, the water-based ionic material may be in a liquid phase or a solid phase at a temperature of 20° C. to 30° C.

[0061] The water-based ion material can be present in an amount of 1 to 20 parts by weight, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 parts by weight, based on 100 parts by weight of the total polyvinyl alcohol resin and the crosslinking agent. Within this range, the water-based ion material can be included in the barrier layer in a suitable amount (for example, 0.5 to 18% by weight, based on 100% by weight of the barrier layer).

[0062] The polyvinyl alcohol resin may be a vinyl-based polymer, which exhibits good properties in terms of adhesiveness when the polarizing plate includes a polyvinyl alcohol-based polarizer as a polarizer.

[0063] The polyvinyl alcohol resin may include polyvinyl alcohol obtained by saponification of vinyl acetate or a derivative thereof, a saponified product of a copolymer of vinyl acetate and a monomer copolymerizable therewith, or a modified polyvinyl alcohol resin obtained by acetylation, urethanization, etherification, grafting, or phosphate esterification of polyvinyl alcohol. These materials may be contained alone or in the form of a mixture. Copolymerizable monomers may include: unsaturated carboxylic acids such as maleic acid (anhydride), fumaric acid, crotonic acid, itaconic acid, (meth)acrylic acid and / or the like, or esters thereof; α-olefins such as ethylene, propylene, and / or the like; (meth)allylsulfonic acid; monoalkyl maleate; sodium disulfonic acid soda alkyl maleate; N-hydroxymethyl acrylamide; alkali metal acrylamide alkylsulfonate; N-vinyl pyrrolidone; N-vinyl pyrrolidone derivatives and / or the like.

[0064] In one embodiment, the polyvinyl alcohol resin may include a polyvinyl alcohol resin containing one or more acetoacetyl groups. The polyvinyl alcohol resin containing one or more acetoacetyl groups may help to improve the bonding strength of the bonding layer.

[0065] In one embodiment, the polyvinyl alcohol resin may have a degree of acetoacetyl modification of 1 mol% to 30 mol%, for example, 1 mol% to 10 mol%. Within these ranges, the polyvinyl alcohol resin can provide sufficient reaction sites with the crosslinking agent to exhibit suitable adhesion while improving the water resistance of the polarizing plate. The method for preparing the polyvinyl alcohol resin containing acetoacetyl groups is not particularly limited. For example, the polyvinyl alcohol resin containing acetoacetyl groups can be prepared by dispersing the polyvinyl alcohol resin in acetic acid and then adding diketene to the resulting mixture, but is not limited thereto.

[0066] The polyvinyl alcohol resin may have an average degree of polymerization of 100 to 3,000 and an average saponification degree of 85 mol % to 100 mol %, but is not limited thereto. Within these ranges, the polyvinyl alcohol resin may further improve adhesion between the polarizer and the barrier layer.

[0067] The polyvinyl alcohol resin can be present in an amount of 1 to 20 parts by weight, for example, 1 to 10 parts by weight, based on 100 parts by weight of an aqueous solvent described in more detail below. Within these ranges, the polyvinyl alcohol resin can prevent or substantially prevent a rapid increase in the viscosity of the barrier layer composition, thereby ensuring good processability and facilitating the preparation of a thin barrier layer, while allowing the barrier layer to have strong adhesion to the polarizer.

[0068] The cross-linking agent may ensure strong adhesion between the barrier layer and the polarizer by cross-linking the polyvinyl alcohol resin.

[0069] The crosslinking agent can be present in an amount of 0.01 to 10 parts by weight, such as 0.1 to 10 parts by weight, and for example, 0.01, 0.1, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts by weight, based on 100 parts by weight of the polyvinyl alcohol resin. Within these ranges, the crosslinking agent can further improve the adhesion between the barrier layer and the polarizer.

[0070] The crosslinking agent may include at least one of an amine-containing crosslinking agent or a metal-containing crosslinking agent. In an embodiment, the crosslinking agent includes a mixture of an amine-containing crosslinking agent and a metal-containing crosslinking agent. According to one embodiment, the amine-containing crosslinking agent may be present in an amount of 50% by weight or greater, for example, 50% by weight to 100% by weight, based on a total of 100% by weight of the crosslinking agent. According to one embodiment, the metal-containing crosslinking agent may be present in an amount of 50% by weight or greater, for example, 50% by weight to 100% by weight, based on a total of 100% by weight of the crosslinking agent. According to one embodiment, the mixture of crosslinking agents may be present in an amount of 95% by weight or greater, for example, 99% by weight to 100% by weight.

[0071] The amine-containing crosslinking agent can react with the polyvinyl alcohol resin to allow the barrier layer (e.g., enable the barrier layer to) have strong adhesion to the polarizer. The crosslinking agent can contain one or more (e.g., two) linear or branched primary amine groups (-NH2) or secondary amine groups (-NH-) to provide higher bonding strength to the binding layer. In addition, by considering the water-based ionic materials described in more detail above, the crosslinking agent is selected from a variety of crosslinking agents used in water-based polyvinyl alcohol binders.

[0072] In one embodiment, the amine-containing cross-linking agent may include at least one polyethyleneimine cross-linking agent.

[0073] The polyethyleneimine crosslinking agent has a primary amine group and / or a secondary amine group, and may include a linear or branched compound having a secondary amine group and / or a tertiary amine group in the main chain. The primary amine group and / or the secondary amine group can react with the functional group (e.g., hydroxyl group or acetoacetyl group) of the polyvinyl alcohol resin to increase the bonding strength.

[0074] The polyethyleneimine cross-linking agent may include a cross-linking agent having ethylene groups (-CH2CH2-) linked through secondary and / or tertiary amine groups and having primary and / or secondary amine groups at their termini (e.g., as known to those skilled in the art).

[0075] The amine-containing crosslinking agent can be present in an amount of 0.01 to 10 parts by weight, for example 0.1 to 5 parts by weight, based on 100 parts by weight of the polyvinyl alcohol resin. Within these ranges, the amine-containing crosslinking agent can further improve the adhesion between the barrier layer and the polarizer.

[0076] As metal-containing crosslinking agents, zirconium-containing compounds can be used. Zirconium-containing compounds may include: zirconium halides, such as zirconium oxychloride, zirconium hydroxychloride, zirconium tetrachloride, zirconium bromide, etc.; zirconium salts of inorganic acids, such as zirconium sulfate, basic zirconium sulfate, zirconium nitrate, zirconium acetate, zirconium carbonate, etc.; zirconium salts of organic acids, such as zirconium formate, zirconium acetate, zirconium propionate, zirconium octoate, zirconium stearate, zirconium lactate, zirconium nitrate, zirconium carbonate, zirconium octoate, zirconium citrate, zirconium phosphate, etc.; zirconium complex salts, such as ammonium zirconium carbonate, sodium zirconium sulfate, ammonium zirconium acetate, ammonium zirconium carbonate, potassium zirconium carbonate, sodium zirconium oxalate, sodium zirconium citrate, ammonium zirconium citrate, and / or ammonium zirconium lactate, and / or zirconium chelate complexes containing at least one chelating agent as a coordinating group. Among these compounds, in one embodiment, the zirconium-containing compound includes a water-soluble zirconium-containing compound, such as zirconium oxyhalide, zirconium oxyacetate, zirconium sulfate, and / or zirconium oxynitrite. In one embodiment, the zirconium-containing compound includes zirconium oxynitrite or a hydrate thereof.

[0077] The metal-containing crosslinking agent can be present in an amount of 0.01 to 10 parts by weight, for example 0.1 to 5 parts by weight, based on 100 parts by weight of the polyvinyl alcohol resin. Within these ranges, the metal-containing crosslinking agent can further improve the adhesion of the barrier layer to the polarizer.

[0078] In the cross-linking agent, the ratio of the amine-containing cross-linking agent to the metal-containing cross-linking agent can be 1:0.1 to 1:5, for example, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3.10, 1:3.11, 1:3.12, 1:3.13, 1:3.14, 1:3.15, 1:3.16, 1:3.17, 1:3.18, 1:3.19, 1:4 , 1:4.8, 1:4.9, 1:5, 1:0.5 to 1:3 weight ratio. Within these ranges, the barrier layer composition can easily achieve the effect of a barrier layer.

[0079] The aqueous solvent can facilitate the deposition of the barrier layer composition to form a thin barrier layer. The aqueous solvent can include water (e.g., ultrapure water and / or the like), but is not limited thereto. The aqueous solvent can be present in the barrier layer composition in a balance.

[0080] The aqueous barrier layer composition may further comprise one or more suitable additives in addition to the aqueous solvent, polyvinyl alcohol resin, crosslinking agent, and aqueous ion material. For example, the additives may include at least one selected from the group consisting of ultraviolet absorbers, heat stabilizers, plasticizers, surfactants, reaction inhibitors, adhesion enhancers, thixotropic agents, conductivity imparting agents, antioxidants, leveling agents, stabilizers, and antistatic agents, but are not limited thereto.

[0081] The barrier layer can be formed by depositing an aqueous barrier layer composition to a predetermined thickness on one surface of the polarizer and then thermally curing the composition. For example, thermal curing is not limited to a specific method and can be achieved by, for example, performing a heat treatment at 40°C to 100°C for 1 minute to 60 minutes. The heat treatment can be performed once, twice, or more times.

[0082] The blocking layer may have a thickness of 10 nm to 500 nm, for example, 50 nm to 200 nm. Within these ranges, the blocking layer may assist (eg, contribute to) reducing the thickness of the polarizing plate.

[0083] polarizer

[0084] The polarizer may include any suitable polarizer (e.g., any polarizer known to those skilled in the art). For example, the polarizer may include a polarizer formed from a polyvinyl alcohol (PVA) resin film or a polypropylene (PP) resin film. For example, the polarizer may be a polyvinyl alcohol-based polarizer comprising at least one dichroic material (e.g., iodine, a dichroic dye, etc.) adsorbed on the polyvinyl alcohol resin film.

[0085] The polyvinyl alcohol resin film may have a saponification degree of 85 mol% to 100 mol%, for example, 98 mol% to 100 mol%. The polyvinyl alcohol resin film may have a degree of polymerization of 1,000 to 10,000, for example, 1,500 to 10,000. Within these ranges of saponification and polymerization degrees, the polyvinyl alcohol resin film may be suitable for forming into a polarizer. The polarizer may be prepared by a suitable method (e.g., a method known to those skilled in the art).

[0086] The polarizer may have a thickness of 5 μm to 30 μm, for example, 5 μm to 25 μm. Within these ranges, the polarizer may be suitable for the polarizing plate and may assist (eg, contribute to) reducing the thickness of the polarizing plate.

[0087] The polarizing plate may further include at least one protective layer.

[0088] protective layer

[0089] A protective layer may be formed on at least one surface of the polarizer to protect the polarizer or provide additional functions to the polarizer.

[0090] The protective layer may include at least one of an optically clear protective film or an optically clear protective coating.

[0091] When the protective layer is a protective film type or type, the protective layer may include a protective film formed by an optically transparent resin. The protective film can be formed by melt extrusion of the resin. If necessary, the resin may be further subjected to a stretching process. The resin may include at least one selected from cellulose ester resins (e.g., triacetyl cellulose, etc.), cyclic polyolefin resins (e.g., cyclic olefin polymers (COP), etc.), polycarbonate resins, polyester resins (e.g., polyethylene terephthalate (PET), etc.), polyether sulfone resins, polysulfone resins, polyamide resins, polyimide resins, non-cyclic polyolefin resins, poly(meth)acrylate resins (e.g., poly(methyl methacrylate)), polyvinyl alcohol resins, polyvinyl chloride resins, and polyvinylidene chloride resins.

[0092] When the protective layer is a protective coating type or species, the protective layer may have good properties in terms of adhesion to the polarizer, transparency, mechanical strength, thermal stability, moisture barrier ability, and durability. In one embodiment, the protective coating as the protective layer may be formed of an actinic radiation-curable resin composition comprising an actinic radiation-curable compound and a polymerization initiator.

[0093] The actinic radiation-curable compound may include at least one selected from a cationically polymerizable curable compound, a radically polymerizable curable compound, a urethane resin, and a silicone resin. The cationically polymerizable curable compound may be an epoxy compound containing at least one epoxy group in its molecule, or an oxetane compound containing at least one oxetane ring in its molecule. The radically polymerizable curable compound may be a (meth)acrylic compound containing at least one (meth)acryloyloxy group in its molecule.

[0094] In addition to the optically transparent resin or actinic radiation curable compound, the protective layer may further comprise one or more suitable additives (e.g., those known to those skilled in the art). Such additives may include antioxidants, ultraviolet absorbers, ion conductors, conductivity imparting agents (e.g., conductive metal oxide particles), light diffusivity imparting additives, viscosity modifiers, and / or the like.

[0095] The protective layer may have a thickness of 5 μm to 200 μm, for example, 20 μm to 120 μm. In an embodiment, the protective layer may have a thickness of 50 μm to 100 μm (in the case of a protective film type) or 5 μm to 50 μm (in the case of a protective coating type). Within these ranges, the protective layer can be suitable for use in optical display devices.

[0096] The protective layer may include a functional coating formed on at least one surface thereof, or may be surface-treated. The functional coating may include, but is not limited to, a hard coating, an anti-fingerprint layer, an anti-reflection layer, a low-reflectivity layer, an ultra-low-reflectivity layer, and / or an anti-glare layer. The surface treatment of the protective layer may include, but is not limited to, corona treatment.

[0097] The protective layer can be bonded to the polarizer or an adherend other than the polarizer via a bonding layer. The bonding layer can be formed of, but is not limited to, a water-based bonding agent or a photocurable bonding agent. The water-based bonding agent and the photocurable bonding agent can be any suitable bonding agent (e.g., bonding agents known to those skilled in the art).

[0098] When the protective layer is formed on the polarizer opposite the first bonding layer, the protective layer may be referred to as an upper protective layer. In this case, the upper protective layer may include an ultraviolet absorber. The ultraviolet absorber can prevent or substantially prevent external light from damaging the optical devices (e.g., light-emitting diodes) in the optical display panel.

[0099] The polarizing plate may further include at least one retardation layer. The retardation layer may be present in a single layer or in a plurality of layers.

[0100] Delay layer

[0101] The retardation layer may improve screen quality by preventing or substantially preventing reflection of external light by circularly polarizing linearly polarized light emitted through the polarizer.

[0102] In one embodiment, the retardation layer may have an in-plane retardation (Re) of 225 nm to 350 nm, for example, 225 nm to 300 nm, corresponding to, for example, a λ / 2 retardation at a wavelength of 550 nm. Within these ranges, the retardation layer can improve screen quality by reducing reflectivity to external light.

[0103] In another embodiment, the retardation layer may have an in-plane retardation (Re) of 100 nm to 220 nm, for example, 100 nm to 180 nm, corresponding to, for example, a λ / 4 retardation at a wavelength of 550 nm. Within these ranges, the retardation layer can improve screen quality by reducing reflectivity to external light.

[0104] In another embodiment, the delay layer may include a stack consisting of a first delay layer and a second delay layer, wherein the first delay layer has an in-plane delay (Re) of 225nm to 350nm, for example, 225nm to 300nm, corresponding to, for example, λ / 2 delay at a wavelength of 550nm, and the second delay layer has an in-plane delay (Re) of 100nm to 220nm, for example, 100nm to 180nm, corresponding to, for example, λ / 4 delay at a wavelength of 550nm.

[0105] The "in-plane retardation (Re)" used in this article can be calculated according to the following equation: Re = (nx-ny)xd, where nx and ny are the refractive indices of the retardation layer in the slow axis direction and the fast axis direction, respectively, and d is the thickness of the retardation layer (unit: nm).

[0106] The retardation layer may have a thickness of 0.01 μm to 30 μm, for example, 1 μm to 10 μm. Within these ranges, the retardation layer may assist (eg, contribute) to reducing the thickness of the polarizing plate while achieving a target retardation.

[0107] The retardation layer may be of film or coating type or kind. In an embodiment, the retardation layer is a coating for reducing the thickness of the polarizing plate.

[0108] The retardation layer may be a liquid crystal layer or a non-liquid crystal layer.

[0109] The film-type or type of retardation layer can be made of a suitable resin (e.g., a resin known to those skilled in the art). For example, the film-type or type of retardation layer can be formed of at least one selected from the group consisting of cellulose ester resins (including triacetyl cellulose (TAC), etc.), cyclic polyolefin (COP) resins (including amorphous cyclic polyolefins, etc.), polycarbonate resins, polyester resins (including polyethylene terephthalate (PET), etc.), polyethersulfone resins, polysulfone resins, polyamide resins, polyimide resins, acyclic polyolefin resins, polyacrylate resins (including poly(methyl methacrylate) resins, etc.), polyvinyl alcohol resins, polyvinyl chloride resins, and polyvinylidene chloride resins.

[0110] Coating Type or Category The retardation layer may be a non-liquid crystal layer, and may include a coating formed from a thermosetting composition, an actinic radiation curable composition, or a coating formed from a liquid crystal composition.

[0111] The polarizing plate may include at least one adhesive layer. The adhesive layer may be present in a single layer or in a plurality of layers.

[0112] Adhesive layer

[0113] The adhesive layer may be used to adhesively bond the barrier layer to the retardation layer, or to adhesively bond the barrier layer to the protective layer.

[0114] In one embodiment, the adhesive layer may be a pressure sensitive adhesive (PSA) layer. For example, the pressure sensitive adhesive layer may include a cured product of a composition including an adhesive resin and a curing agent.

[0115] Figure 1 is a cross-sectional view of a polarizing plate according to an embodiment. Figure 1 , the polarizing plate may include: a polarizer 100 ; a protective layer 200 stacked on an upper surface of the polarizer 100 ; and a blocking layer 300 formed on a lower surface of the polarizer 100 .

[0116] Figure 2 is a cross-sectional view of a polarizing plate according to another embodiment. Figure 2 , the polarizing plate may include: a polarizer 100; a protective layer 200 formed on an upper surface of the polarizer 100; and a barrier layer 300, an adhesive layer 400, and a retardation layer 500 sequentially stacked on a lower surface of the polarizer 100.

[0117] In some embodiments, the protective layer 200 may be bonded to the polarizer 100 via a bonding layer. The bonding layer may be formed of a water-based bonding agent or a photocurable bonding agent.

[0118] An optical display device according to the present disclosure includes the polarizing plate according to the present disclosure.

[0119] For example, the optical display device may include a light-emitting display including an organic light-emitting display, etc. For example, the optical display device may include a flexible optical display device.

[0120] Next, the present disclosure will be described in more detail with reference to some examples. However, it should be noted that these examples are provided for illustrative purposes only and should not be interpreted as limiting the present disclosure in any way.

[0121] Example 1

[0122] Preparation of polarizers

[0123] A polyvinyl alcohol film (PS#60, degree of polymerization: 2800, thickness: 60 μm, Kuraray) was dyed in an aqueous solution containing 0.3% iodine at a temperature of 55°C. The dyed film was uniaxially stretched to 6.0 times its original length in the machine direction (MD) of the film. The stretched polyvinyl alcohol film was immersed in an aqueous solution containing 3% by weight of boric acid and 2% by weight of potassium iodide for color correction. The resulting product was dried at 50°C for 4 minutes to provide a polarizer (thickness: 25 μm, light transmittance: 45%).

[0124] Preparation of aqueous barrier layer compositions

[0125] A polyvinyl alcohol resin is dissolved in 100 parts by weight of water at 95° C. while stirring for 60 minutes. The resulting solution is cooled (e.g., completely cooled) to room temperature and then mixed with a mixture of a zirconium-containing curing agent and an amine curing agent to prepare a mixture of the polyvinyl alcohol resin, the zirconium-containing curing agent, and the amine curing agent.

[0126] The polyvinyl alcohol resin was Z200 available from Mitsubishi Chemical Co. Ltd.

[0127] The zirconium-containing curing agent is a zirconium zinc complex (Zircosol Zn) (ZrO(NO 3 ) 2 ) available from Daiichi Kigenso Kagaku Kogyo Co., Ltd.

[0128] The amine curing agent was SP018 (polyethyleneimine crosslinking agent) available from Nippon Shokubai Co., Ltd.

[0129] The mixture of the polyvinyl alcohol resin, the zirconium-containing curing agent, and the amine curing agent includes, in terms of solid content, 100 parts by weight of the polyvinyl alcohol resin, 5 parts by weight of the zirconium-containing curing agent, and 5 parts by weight of the amine curing agent.

[0130] A water-based barrier layer composition was prepared by adding 20 parts by weight of N,N-bis(2-hydroxyethyl)-N-(3'-dodecyloxy-2'-hydroxypropyl)methyl ammoniummethyl sulfate of Formula 1-1 to 100 parts by weight of a mixture of a polyvinyl alcohol resin, a zirconium-containing curing agent, and an amine curing agent.

[0131] Formula 1-1

[0132]

[0133] Table 1 below shows the content of the compound of Formula 1 based on 100 parts by weight of a mixture including 100 parts by weight of a polyvinyl alcohol resin, 5 parts by weight of a zirconium-containing curing agent, and 5 parts by weight of an amine curing agent.

[0134] In Table 1, "-" indicates that the corresponding component does not exist.

[0135] Polarizing plate manufacturing

[0136] 3 parts by weight of a polyvinyl alcohol resin (Z200, polyvinyl alcohol modified with acetoacetyl groups, average degree of polymerization: 1,200, average degree of saponification: 99 mol%, degree of acetoacetyl modification: 5 mol%, Mitsubishi Chemical Corporation) was dissolved in 100 parts by weight of water at 95°C and stirred for 60 minutes. The resulting solution was cooled (e.g., completely cooled) to room temperature, and then an amine crosslinker (SP018, solids content: 40 wt%, polyethyleneimine crosslinker, Nippon Shokubai Co., Ltd.) was added to the resulting solution to prepare a binder. In terms of solids content, the polyethyleneimine crosslinker was present in an amount of 1 part by weight per 100 parts by weight of the polyvinyl alcohol resin.

[0137] The prepared binder was deposited on the upper surface of the polarizer to a predetermined thickness, and the lower surface of the COP film (having a hard coating layer formed on its upper surface, thickness: 28 μm, Zeon Co., Ltd.) was adhered to the upper surface of the polarizer through the binder, and dried in an oven at 50°C for 1 minute and at 85°C for 3 minutes to bond the COP film to the upper surface of the polarizer.

[0138] The prepared aqueous barrier layer composition was deposited to a predetermined thickness on the lower surface of the polarizer, and then an unsaponified triacetyl cellulose film (thickness: 40 μm, standard TAC) was attached to the composition.

[0139] Then, the barrier layer composition was dried at 80°C for 3 minutes, and the unsaponified triacetyl cellulose film was removed therefrom, thereby preparing a polarizing plate in which a COP film (thickness: 28 μm), an adhesive layer (thickness: 3 μm), a polarizer (thickness: 25 μm) and a barrier layer (thickness: 100 nm) were stacked in the order stated.

[0140] Examples 2 to 5 and Comparative Example 1

[0141] A polarizing plate was prepared in the same manner as in Example 1, except that the amount of N,N-bis(2-hydroxyethyl)-N-(3'-dodecyloxy-2'-hydroxypropyl)methylammonium methylsulfate of Formula 1-1 was changed based on 100 parts by weight of the mixture of the polyvinyl alcohol resin, the zirconium-containing curing agent and the amine curing agent in the aqueous composition as listed in Table 1.

[0142] Example 6

[0143] A polarizing plate was prepared in the same manner as in Example 1, except that 20 parts by weight of stearamidopropyldimethyl-2-hydroxyethylammonium nitrate of Formula 1-2 was used instead of the compound of Formula 1-1.

[0144] Formula 1-2

[0145]

[0146] Examples 7 to 10 and Comparative Example 2

[0147] A polarizing plate was prepared in the same manner as in Example 6, except that the amount of stearamidopropyl dimethyl-2-hydroxyethyl ammonium nitrate of Formula 1-2 based on 100 parts by weight of the mixture of the polyvinyl alcohol resin, the zirconium-containing curing agent and the amine curing agent in the aqueous composition was changed as listed in Table 1.

[0148] Comparative Example 3

[0149] A polarizing plate was prepared in the same manner as in Example 1, except that the compound of Formula 1-1 was not used.

[0150] The compositions of the polarizing plates prepared in Examples and Comparative Examples are shown in Table 1, and the color changes of the polarizing plates of Examples and Comparative Examples were evaluated.

[0151] The samples were prepared by forming a pressure-sensitive adhesive layer (acrylic PSA) on the lower surface of the polarizing plate and then bonding a glass plate to the lower surface through the pressure-sensitive adhesive layer. The prepared samples were placed in a chamber under constant temperature / humidity conditions of 60°C and 95% relative humidity (RH) for 500 hours. It was evaluated whether the color of the barrier layer, the pressure-sensitive adhesive layer, and the glass plate turned purple due to the elution of iodine from the polarizer. Samples with no color change were rated as ◎, samples that allowed partial color change but were still suitable for use were rated as ○, samples that allowed partial color change but were not suitable for use were rated as △, and samples that allowed overall color change (for example, significant color change occurred in the barrier layer and / or pressure-sensitive layer) were rated as x.

[0152] Table 1

[0153]

[0154] *In Table 1, "mixture" means a mixture of a polyvinyl alcohol resin, a zirconium-containing crosslinking agent, and an amine crosslinking agent.

[0155] As shown in Table 1, it can be seen that the polarizing plate according to the present disclosure does not undergo color change by using a barrier layer instead of a protective layer on at least one surface of the polarizer and by preventing or substantially preventing the dichroic material from eluting from the polarizer after being placed under high temperature / humidity conditions for a long time.

[0156] On the other hand, it can be seen that the polarizing plate of Comparative Example 3, which does not contain the water-like ion material, undergoes an overall (or significant) color change and fails to provide the same effect as the polarizing plates of Examples. Compared to Examples 1 and 2, the polarizing plates of Comparative Examples 1 and 2, which contain more than 18% by weight of the water-like ion material, exhibit (e.g., unsatisfactory) color changes.

[0157] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. In addition, when "may" is used to describe an embodiment of the present disclosure, it is associated with "one or more embodiments of the present disclosure." For example, expressions such as "at least one of..." and "any of...", when used before a series of elements, modify the elements of the entire series rather than modifying the individual elements of the series. When phrases such as "at least one of A, B, and C," "at least one of A, B, or C," "at least one selected from the group of A, B, and C," or "at least one selected from A, B, and C" are used to specify a series of elements A, B, and C, the phrases may refer to any and all suitable combinations or subsets of A, B, and C, such as A, B, C, A and B, A and C, B and C, or A and B and C.

[0158] As used herein, the terms “use,” “using,” and “used” may be considered synonymous with the terms “utilize,” “utilizing,” and “utilized,” respectively. It should be understood that although terms such as “first,” “second,” and “third” may be used herein to describe various elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below may be termed a second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0159] In addition, any numerical range disclosed and / or described herein is intended to include all subranges of the same numerical precision that fall within the range. For example, a range of "1.0 to 10.0" is intended to include all subranges between (and including) the minimum value of 1.0 and the maximum value of 10.0, i.e., having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as (for example) 2.4 to 7.6. Any maximum numerical limit described herein is intended to include all lower numerical limits subsumed therein, and any minimum numerical limit described in this specification is intended to include all higher numerical limits subsumed therein. Therefore, the applicant reserves the right to amend this specification (including the claims) to explicitly recite any subranges that fall within the range explicitly recited herein.

[0160] It should be understood that without departing from the spirit and scope of the present disclosure, those skilled in the art may make various modifications, changes, variations and equivalent embodiments. The technical scope of the present disclosure should be defined by the appended claims and their equivalents.

Claims

1. A polarizing plate, comprising: Polarizer; as well as a blocking layer, located on one surface of the polarizer, wherein the barrier layer comprises a cured product of a composition comprising a polyvinyl alcohol resin, a crosslinking agent and a water-based ion material, and The amount of the water-based ion material in the barrier layer is 0.5 wt % to 18 wt % based on 100 wt % of the total barrier layer. 2 . The polarizing plate according to claim 1 , wherein the amount of the water-based ion material in the composition is 1 part by weight to 20 parts by weight based on 100 parts by weight of the polyvinyl alcohol resin and the cross-linking agent in total. 3 . The polarizing plate according to claim 1 , wherein the water-based ion material is in a liquid phase at a temperature of 20° C. to 30° C. The polarizing plate according to claim 1 , wherein the water-based ion material comprises ammonium-based cations and anions. The polarizing plate according to claim 4 , wherein the ammonium-based cation has a hydroxyl group or an aliphatic or aromatic hydrocarbon group substituted with a hydroxyl group. The polarizing plate according to claim 4 , wherein the anion comprises a nitrate anion or a sulfate anion.

7. The polarizing plate according to claim 1, wherein the water-based ion material comprises a compound represented by Formula 1: R 1 R 2 R 3 R 4 N + X, wherein X is a monovalent nitrate anion or a monovalent sulfate anion; and R 1 、R 2 、R 3 and R 4 Each independently represents a substituted or unsubstituted linear or branched C1 to C 10 Alkyl or substituted or unsubstituted C6 to C 20 Aryl.

8. The polarizing plate according to claim 7, wherein R in Formula 1 1 、R 2 、R 3 or R 4 At least one of the C1 to C 10 Alkyl, or C6 to C substituted by hydroxyl 20 Aryl.

9. The polarizing plate according to claim 7, wherein R in Formula 1 1 、R 2 、R 3 or R 4 At least one of the linear or branched C 10 to C 20 Alkyl or linear or branched C 10 to C 20 Alkoxy substitution.

10. The polarizing plate according to claim 1, wherein the water-based ion material comprises at least one compound represented by Formula 1-1 and Formula 1-2: Formula 1-1 Formula 1-2 The polarizing plate according to claim 1 , wherein the cross-linking agent comprises at least one of an amine-containing cross-linking agent and a metal-containing cross-linking agent.

12. The polarizing plate according to claim 1, wherein the composition comprises: 100 parts by weight of the polyvinyl alcohol resin, Based on 100 parts by weight of the polyvinyl alcohol resin, 0.01 parts by weight to 10 parts by weight of the cross-linking agent, and Based on 100 parts by weight of the polyvinyl alcohol resin and the cross-linking agent in total, 1 part by weight to 20 parts by weight of the water-based ion material. 13 . The polarizing plate according to claim 1 , wherein the composition is an aqueous composition. The polarizing plate according to claim 1 , wherein the blocking layer is directly located on the polarizer.

15. The polarizing plate according to claim 1, further comprising: At least one of a protective layer, a retardation layer, and an adhesive layer.

16. An optical display device comprising the polarizing plate according to claim 1.

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