Polarizing plate, composition for barrier layer, and display device

Abstract

To provide a polarizing plate that does not have a protection layer at least on one surface of a polarizer and prevents elution of iodine eluted from the polarizer after the polarizing plate is left under high temperature and high humidity for a long time.SOLUTION: A polarizing plate includes a polarizer, and barrier layer formed on one surface of the polarizer. The barrier layer includes: a curable compound including an epoxy compound including an alicyclic epoxy compound and a bisphenol epoxy compound, and a (meth)acrylic compound; a photo-initiator; and a glycol compound. The bisphenol epoxy compound is contained by 20 parts by weight to 70 parts by weight per 100 parts by weight of the curable compound. The glycol compound includes a cured substance of a composition contained by 1 part by weight to 15 parts by weight per 100 parts by weight of the curable compound.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a polarizing plate, a composition for a barrier layer, and a display device. [Background technology]

[0002] Light-emitting display devices, including organic light-emitting display devices, do not necessarily have to include a polarizer. However, incident external light may be totally reflected by the panel in the light-emitting display device, degrading the image quality. Therefore, light-emitting display devices generally include a polarizer on the upper surface of the panel. The polarizer is composed of a polarizer and a retardation film. The retardation film may be a polymer film, but in recent years, liquid crystal films have been used in line with the trend toward thinner displays.

[0003] Meanwhile, in recent years, with the trend toward thinner polarizing plates, a method of laminating a barrier layer on a polarizing plate instead of a protective layer has been considered. The barrier layer is generally formed by coating and curing a barrier layer composition, and therefore can be thinner than existing protective layers.

[0004] The background art of the present invention is described in Japanese Patent Application Laid-Open No. 2014-032270. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-032270 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a polarizing plate that does not have a protective layer on at least one side of the polarizer and that prevents iodine from eluting from the polarizer after being left at high temperature and high humidity for a long period of time.

[0007] Another object of the present invention is to provide a polarizing plate which does not have a protective layer on at least one side of the polarizer and which has excellent bending reliability even after being left at high temperature and high humidity for a long period of time.

[0008] A further object of the present invention is to provide a highly reliable polarizing plate which does not have a protective layer on at least one surface of the polarizer, which prevents discoloration of the polarizer after high temperature and humidity. [Means for solving the problem]

[0009] One aspect of the present invention is a polarizing plate.

[0010] The polarizing plate includes a polarizer and a barrier layer formed on one surface of the polarizer, and the barrier layer includes a cured product of a composition including: an epoxy-based compound including an alicyclic epoxy-based compound and a bisphenol-based epoxy-based compound; and a curable compound including a (meth)acrylic compound; a photoinitiator; and a glycol-based compound; wherein the bisphenol-based epoxy-based compound is included in an amount of 20 to 70 parts by weight per 100 parts by weight of the curable compound, and the glycol-based compound is included in an amount of 1 to 15 parts by weight per 100 parts by weight of the curable compound.

[0011] Another aspect of the present invention is a composition for a barrier layer.

[0012] The composition for the barrier layer includes a curable compound including an epoxy compound including an alicyclic epoxy compound and a bisphenol epoxy compound, and a (meth)acrylic compound; a photoinitiator; and a glycol compound; wherein the bisphenol epoxy compound is included in an amount of 20 to 70 parts by weight based on 100 parts by weight of the curable compound, and the glycol compound is included in an amount of 1 to 15 parts by weight based on 100 parts by weight of the curable compound.

[0013] Yet another aspect of the present invention relates to a display device.

[0014] The display device includes the polarizing plate. [Effects of the Invention]

[0015] The present invention does not have a protective layer on at least one side of the polarizer, thereby providing a thin polarizing plate. Furthermore, by preventing iodine from leaching out from the polarizer after long-term storage at high temperature and high humidity, changes in light transmittance due to iodine sublimation are minimal, and corrosion of display panel due to iodine leaching can be prevented. Furthermore, the polarizing plate of the present invention has excellent flexural reliability even after long-term storage at high temperature and high humidity, providing high reliability when applied to flexible display devices. Furthermore, the polarizing plate of the present invention can prevent discoloration of the polarizer even after long-term storage at high temperature and high humidity, thereby providing excellent reliability. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a cross-sectional view of a polarizing plate according to an embodiment of the present invention. [Figure 2] FIG. 10 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention. [Figure 3] FIG. 1 is a schematic diagram for evaluating the resistance of a polarizing plate. [Figure 4] FIG. 1 is a schematic diagram showing a general explanation for evaluating discoloration of a polarizer (discoloration of iodine). [Figure 5] FIG. 10 is a schematic diagram for evaluating bending reliability. DETAILED DESCRIPTION OF THE INVENTION

[0017] With reference to the accompanying drawings, the present invention will be described in detail with respect to the embodiments so that those skilled in the art can easily implement the present invention. The present invention may be realized in various different forms and is not limited to the embodiments described herein. In the drawings, parts that are not relevant to the description are omitted to clearly explain the present invention, and the same reference numerals are used throughout the specification to refer to the same or similar components. In the drawings, the length, thickness, etc. of each component are shown for the purpose of explaining the present invention, and the present invention is not limited to the length, thickness, etc. shown in the drawings.

[0018] The terms used herein are for illustrative embodiments only and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates a different meaning.

[0019] As used herein, "upper" and "lower" are based on the drawings and are not necessarily fixed to the upper and lower parts. Depending on the viewing perspective, "upper" may be changed to "lower" and "lower" may be changed to "upper".

[0020] As used herein, "in-plane retardation (Re)" is represented by the following formula A: [Formula A] Re = (nx - ny) × d (In the above formula A, nx and ny are the refractive indices in the slow axis direction and the fast axis direction of the optical element at the measurement wavelength, respectively, and d is the thickness of the optical element (unit: nm).)

[0021] As used herein, "negative wavelength dispersion" means Re(450) < Re(550) < Re(650).

[0022] The present invention relates to a polarizing plate having no protective layer on at least one surface of a polarizer. The polarizing plate includes a barrier layer instead of the protective layer.

[0023] Here, the "protective layer" means an optical element laminated on one surface of the polarizer and having a function of protecting the polarizer. The protective layer may be a film or a coating layer. The protective layer may be a liquid crystal layer or a non-liquid crystal layer. The protective layer may also have an in-plane retardation within a predetermined range at a wavelength of 550 nm, or may have no in-plane retardation. <00,00131> In one embodiment, the protective layer may be an optically transparent protective film or protective coating layer, and may include any of the conventional materials known to those skilled in the art. For example, the protective film may include one or more of cellulose ester-based resins such as triacetyl cellulose (TAC), cyclic polyolefin (COP)-based resins such as amorphous cyclic polyolefin, polycarbonate-based resins, polyester-based resins such as polyethylene terephthalate (PET), polyethersulfone-based resins, polysulfone-based resins, polyamide-based resins, polyimide-based resins, acyclic polyolefin-based resins, polyacrylate-based resins such as polymethyl methacrylate resin, polyvinyl alcohol-based resins, polyvinyl chloride-based resins, and polyvinylidene chloride-based resins.

[0025] In one embodiment, the barrier layer may be formed directly on the polarizer. Here, "directly formed" means that the barrier layer is formed on the polarizer without any adhesive or pressure-sensitive adhesive layer between the polarizer and the barrier layer. For example, the barrier layer may be formed by coating or applying a barrier layer composition described below directly onto one side of the polarizer, followed by drying and curing.

[0026] In an embodiment, the polarizing plate may include a polarizer, a protective layer laminated on one surface of the polarizer, and a barrier layer laminated on the other surface of the polarizer.

[0027] As described below, the barrier layer may be formed by applying a barrier layer composition to one surface of a polarizer and then curing it. Therefore, the barrier layer must be thin. Polarizers contain a dichroic material such as iodine to provide polarization performance. When a polarizing plate is left in a high-temperature, high-humidity environment for a long period of time, the dichroic material such as iodine may leach out of the polarizer. The leached dichroic material may corrode the optical display panel, particularly the substrate, to which the polarizing plate is attached, and may reduce the light transmittance of the polarizing plate due to sublimation. Furthermore, the leached dichroic material may reduce the sensitivity of the touch panel of the display device.

[0028] A polarizing plate according to one embodiment includes a barrier layer, as described below. The polarizing plate can prevent corrosion of the substrate after long-term storage at high temperature and humidity because the dichroic material eluted from the polarizer cannot pass through the barrier layer. The polarizing plate also exhibits low change in light transmittance, providing reliability. Furthermore, the polarizing plate exhibits excellent flexural reliability after long-term storage at high temperature and humidity, making it suitable for flexible display devices. Furthermore, the polarizing plate exhibits no discoloration of the polarizer after long-term storage at high temperature and humidity, thereby enhancing the reliability of the polarizing plate. Furthermore, the barrier layer can prevent the passage of the dichroic material, thereby improving the sensitivity of touch panels in display devices.

[0029] The polarizing plate according to an embodiment may be used as an anti-reflection polarizing plate in an organic light-emitting device display device, etc. The polarizing plate according to an embodiment may be used in a flexible, foldable, or bendable optical display device that requires bending reliability.

[0030] A polarizing plate according to one embodiment will be described below.

[0031] The polarizing plate includes a polarizer and a barrier layer formed on one surface of the polarizer.

[0032] Barrier layer

[0033] The polarizing plate may contain one or more barrier layers.

[0034] The barrier layer includes a cured product of a composition including: an epoxy compound including an alicyclic epoxy compound and a bisphenol epoxy compound; a curable compound including a (meth)acrylic compound; a photoinitiator; and a glycol compound.

[0035] In one embodiment, the barrier layer may be a photocured version of the composition.

[0036] In one embodiment, the barrier layer may include a curable compound including an epoxy-based compound, including an alicyclic epoxy-based compound and a bisphenol-type epoxy-based compound, and a (meth)acrylic-based compound; a photoinitiator; and a glycol-based compound, which may be derived from the composition.

[0037] In one embodiment, the curable compound may be contained in the composition in an amount of 90% by weight or more, for example, 90% by weight to 95% by weight, based on the solid content.

[0038] In one embodiment, the total amount of the epoxy compound and the (meth)acrylate compound may be 95 parts by weight or more, for example, 99 to 100 parts by weight, or 100 parts by weight, per 100 parts by weight of the curable compound. Within this range, excellent improvements in adhesion, reliability, and compatibility of the barrier layer with the polarizer can be expected.

[0039] The curable compound may be a photocurable compound.

[0040] (A) Epoxy compounds The epoxy compound (A) may be included in an amount of 30 to 80 parts by weight per 100 parts by weight of the curable compound. This range avoids the problem of insufficient adhesion to the polarizer due to a lack of (meth)acrylic compound, and also eliminates the problem of poor polarizer discoloration after long-term storage under high temperature and humidity conditions due to a decrease in the overall glass transition temperature of the barrier layer and insufficient bonding strength with the polarizer. Preferably, the epoxy compound may be included in an amount of 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, or 80 parts by weight, 30 to 70 parts by weight, 40 to 70 parts by weight, or 50 to 70 parts by weight.

[0041] The epoxy compound includes a mixture of an alicyclic epoxy compound and a bisphenol type epoxy compound.

[0042] In one embodiment, the total amount of the alicyclic epoxy compound and the bisphenol epoxy compound may be 95 parts by weight or more, for example, 99 to 100 parts by weight, for example, 100 parts by weight, per 100 parts by weight of the epoxy compound. Within this range, the effects of the present invention may be easily achieved.

[0043] A polarizing plate including a barrier layer formed from a composition that does not contain the alicyclic epoxy compound may have problems such as a lowered glass transition temperature and a lowered adhesion to a polarizer.

[0044] A polarizing plate including a barrier layer formed of a composition that does not contain the bisphenol-type epoxy compound may have a problem in that the affinity of iodine in the PVA is high, accelerating the elution of iodine.

[0045] In one embodiment, the total amount of the alicyclic epoxy compound and the bisphenol epoxy compound may be 95 parts by weight or more, preferably 99 to 100 parts by weight, and more preferably 100 parts by weight, per 100 parts by weight of the epoxy compound (A). Within this range, the effects of the present invention may be easily achieved.

[0046] The alicyclic epoxy compound may be a bifunctional alicyclic epoxy compound having a main chain of a linear or branched alkylene group having 4 or more carbon atoms between two alicyclic epoxy groups. Compared to CELLOXIDE 2021P, a commonly used conventional epoxy compound, this alicyclic epoxy compound has a larger number of carbon atoms between the two alicyclic epoxy groups, providing greater flexibility and thereby increasing the curing rate of the barrier layer composition and improving adhesion to polarizers. The inventors of the present invention have found that bifunctional alicyclic epoxy compounds having a main chain of a linear alkylene group having less than 4 carbon atoms, e.g., 1 to 3 carbon atoms, between the two alicyclic epoxy groups do not function well as a barrier layer.

[0047] In this specification, the term "number of carbon atoms" refers only to the number of carbon atoms contained in the main chain of a linear or branched alkylene group or alkyl group, and does not include the number of carbon atoms contained in the side chain.

[0048] In one embodiment, the content of the compound having a main chain of a linear alkylene group having less than 4 carbon atoms between two alicyclic epoxy groups may be less than 0.5 parts by weight, for example, 0 to less than 0.5 parts by weight, per 100 parts by weight of the curable compound. Within this range, the above-described effects of the present invention may be easily achieved.

[0049] In one embodiment, the alicyclic epoxy compound may have a main chain of a linear alkylene group having 4 to 10 carbon atoms, for example, 4 to 6 carbon atoms, between two alicyclic epoxy groups.

[0050] In one embodiment, the alicyclic epoxy compound may have one or more units of the following Chemical Formula 1 between two alicyclic epoxy groups: [Chemical formula 1] *-X 1 -R 2 -* (In the above chemical formula 1, * represents a linking site of elements, X 1 is -OC(=O)- or -C(=O)-O-, R 2 is a linear or branched alkylene group having 4 or more carbon atoms.

[0051] In one embodiment, the alicyclic epoxy-based compound may include a compound of Formula 2: [Chemical formula 2]

[0052] [ka] (In the above Chemical Formula 2, R 1 , R 3each independently represents a single bond or a linear or branched alkylene group having 1 to 5 carbon atoms, X 1 , X 2 are each independently -OC(=O)- or -C(=O)-O-, R 2 is a linear or branched alkylene group having 4 or more carbon atoms, n is an integer equal to or greater than 1, R 4 , R 5 are each independently an alkyl group having 1 to 5 carbon atoms, a and b are each independently an integer from 0 to 9.

[0053] Preferably, in the above formula 2, R 1 , R 3 may each independently be a single bond, or a linear or branched alkylene group having 1 to 3 carbon atoms, for example, a single bond or a methylene group.

[0054] Preferably, in the above formula 2, R 2 may be a linear alkylene group having 4 to 10 carbon atoms, preferably 4 to 6 carbon atoms.

[0055] Preferably, in Chemical Formula 2, n may be 1 to 10, for example, 1 to 5, for example, 1 to 3.

[0056] For example, the alicyclic epoxy compound may include one or more compounds of the following formulas 2-1 and 2-2: [Chemical formula 2-1] Bis(3,4-epoxycyclohexylmethyl)adipate

[0057] [ka] [Chemical Formula 2-2] 3,4-Epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate Modified ε-Caprolactone

[0058] [ka]

[0059] The alicyclic epoxy compound is used in an amount of 1 to 50 parts by weight, for example, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 37 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, 50 parts by weight, 51 parts by weight, 52 parts by weight, 53 parts by weight, 54 parts by weight, 55 parts by weight, 56 parts by weight, 57 parts by weight, 58 parts by weight, 59 parts by weight, 60 parts by weight, 61 parts by weight, 62 parts by weight, 63 parts by weight, 64 parts by weight, 65 parts by weight, 66 parts by weight, 67 parts by weight, 68 parts by weight, 69 parts by weight, 70 parts by weight, 71 parts by The amount of the bisphenol-based epoxy compound may be 3 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 37 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, or 50 parts by weight, or 1 to 30 parts by weight, 1 to 20 parts by weight, or 5 to 20 parts by weight. Within this range, the bisphenol-based epoxy compound may provide high adhesion to the polarizer and a fast curing speed, and may not interfere with the reaction of the bisphenol-based epoxy compound, thereby increasing the degree of curing of the composition.

[0060] In one embodiment, the alicyclic epoxy compound is contained in the epoxy compound (A) in an amount of 5 to 50 parts by weight, for example, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, The amount of the bisphenol-based epoxy compound may be 5 to 20 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 37 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, or 50 parts by weight, 5 to 20 parts by weight, or 10 to 20 parts by weight. Within this range, the bisphenol-based epoxy compound may have a beneficial effect on the physical properties of the polarizing plate after high temperature and humidity exposure, and may increase the degree of curing of the barrier layer by not interfering with the curing reaction of the bisphenol-based epoxy compound, which has a relatively slow reaction rate.

[0061] In one embodiment, the epoxy compound having a linear or branched alkylene main chain having 4 or more carbon atoms between two alicyclic epoxy groups may be contained in the curable compound in an amount of 95% by weight or more, for example, 99% to 100% by weight, for example, 100% by weight. Within this range, the effects of the polarizing plate of the present invention described above can be easily achieved.

[0062] The composition for the barrier layer includes an aromatic epoxy compound, such as a bisphenol epoxy compound. The inventors of the present invention have confirmed that the composition, when containing a bisphenol epoxy compound and a glycol compound described below, has the effect of preventing the leaching of iodine.

[0063] In one embodiment, the bisphenol epoxy compound may be a bifunctional epoxy compound having two epoxy groups, which can enhance the degree of cure of the barrier layer by complementing the slow reaction rate of the bisphenol epoxy compound.

[0064] For example, the bisphenol-type epoxy compound may include at least one of a bisphenol A-type epoxy compound, a bisphenol F-type epoxy compound, and a bisphenol S-type epoxy compound. For example, the bisphenol-type epoxy compound may include at least one of a bisphenol A-type epoxy compound and a bisphenol F-type epoxy compound.

[0065] The bisphenol epoxy compound may be included in an amount of 20 to 70 parts by weight, for example, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, or 70 parts by weight, 30 to 60 parts by weight, or 40 to 50 parts by weight, relative to 100 parts by weight of the total of the curable compounds, for example, the (A) epoxy compound and the (B) (meth)acrylic compound. Within this range, the effect of preventing iodine leaching from the barrier layer may be enhanced.

[0066] In one embodiment, the bisphenol epoxy compound may be included in the (A) epoxy compound in an amount of 50 to 95 parts by weight, for example, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, or 95 parts by weight, 80 to 95 parts by weight, or 80 to 90 parts by weight. This range may have a beneficial effect on the physical properties of the polarizing plate after high temperature and humidity exposure, and may increase the degree of curing of the barrier layer by not interfering with the curing reaction of the bisphenol epoxy compound, which has a relatively slow reaction rate.

[0067] In one embodiment, the bisphenol epoxy compound may be included in the aromatic epoxy compound contained in the curable compound in an amount of 95 wt % or more, for example, 99 wt % to 100 wt %, for example, 100 wt %, which may easily achieve the effects of the polarizing plate of the present invention.

[0068] (B) (Meth)acrylic compound The (B) (meth)acrylic compound may be contained in an amount of 20 to 70 parts by weight per 100 parts by weight of the curable compound. This range may facilitate improved adhesive strength, reliability, and compatibility. For example, the (meth)acrylic compound may be contained in an amount of 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, or 70 parts by weight, 30 to 70 parts by weight, 30 to 60 parts by weight, or 30 to 50 parts by weight.

[0069] The (meth)acrylic compound has a faster curing rate than epoxy compounds during photoradical polymerization, thereby improving process stability by rapidly curing the composition. In addition, the (meth)acrylic compound has a low affinity for iodine, which may prevent it from affecting the decolorization of iodine.

[0070] The (meth)acrylic compound may include one or more of a monofunctional (meth)acrylic compound and a difunctional (meth)acrylic compound.

[0071] For example, the (meth)acrylic compound may include a mixture of a monofunctional (meth)acrylic compound and a difunctional (meth)acrylic compound, and the monofunctional (meth)acrylic compound and the difunctional (meth)acrylic compound may be included in the mixture in a weight ratio of 1:1 to 1:3, for example, 1:1 to 1:2.

[0072] According to one embodiment, the monofunctional (meth)acrylic compound may include a (meth)acrylate having an aromatic group. A polarizing plate including a barrier layer formed from a composition that does not include the (meth)acrylate having an aromatic group may have a problem of reduced peel strength between the liquid crystal and the alignment film. The (meth)acrylate having an aromatic group can provide high adhesion to the liquid crystal retardation layer described below.

[0073] The (meth)acrylate having an aromatic functional group may include, for example, one or more compounds of the following Chemical Formula 3: [Chemical formula 3] CH2=CR 7 -C(=O)-O-(-CH2-)sR 8 (In the above Chemical Formula 3, R 7 is hydrogen or a methyl group, s is an integer from 0 to 10, R 8 is a substituted or unsubstituted aryl group having 6 to 50 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 50 carbon atoms).

[0074] Here, "substituted" means that one or more hydrogen atoms of the functional group have been substituted with an alkyl group having 1 to 10 carbon atoms.

[0075] Preferably, the (meth)acrylate having an aromatic functional group may include one or more of benzyl (meth)acrylate and phenoxyethyl (meth)acrylate.

[0076] The monofunctional (meth)acrylic compound, e.g., a (meth)acrylate having an aromatic group, may be included in an amount of 5 to 50 parts by weight, preferably 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 parts by weight, 5 to 30 parts by weight, or 5 to 25 parts by weight, based on a total of 100 parts by weight of the curable compound, e.g., the (A) epoxy compound and the (B) (meth)acrylic compound. This range can provide effects of increasing the peel strength between the liquid crystal retardation layer and the alignment film after high temperature and high humidity and improving the reliability of the polarizing plate. Furthermore, the initial reaction rate can be slowed, and the polarizing plate can remain uncured, thereby eliminating the problem of promoting iodine sublimation in the polarizer when left at high temperature and high humidity.

[0077] The monofunctional (meth)acrylic compound, for example, a (meth)acrylate having an aromatic group, may be included in an amount of 10 to 60 parts by weight, for example, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 parts by weight, 20 to 60 parts by weight, or 20 to 50 parts by weight, based on a total of 100 parts by weight of the (B) (meth)acrylic compound. Within this range, improvement in adhesive strength, reliability, and compatibility may be facilitated.

[0078] The bifunctional (meth)acrylic compound may contain a bifunctional (meth)acrylate having an alkylene glycol group. A polarizing plate including a barrier layer formed from a composition that does not contain the bifunctional (meth)acrylate having an alkylene glycol group may have a problem of slow radical curing speed.

[0079] The alkylene glycol group may be ethylene oxide or propylene oxide.

[0080] The alkylene glycol group may be contained in the bifunctional (meth)acrylic compound in an amount of 1 mole or more, for example, 2 moles or more, such as 2 moles to 5 moles. Within this range, the effects of the present invention can be easily achieved.

[0081] For example, the bifunctional (meth)acrylate having an alkylene glycol group may be one or more of diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, and tripropylene glycol di(meth)acrylate. Preferably, the bifunctional (meth)acrylic compound may be one or more of dipropylene glycol di(meth)acrylate and tripropylene glycol di(meth)acrylate.

[0082] The bifunctional (meth)acrylic compound, for example, a bifunctional (meth)acrylate having an alkylene glycol group, may be contained in an amount of 5 to 50 parts by weight, for example, 5, 10, 15, 20, 25, 30, 34, 40, 45, or 50 parts by weight, 5 to 30 parts by weight, or 5 to 25 parts by weight, per 100 parts by weight of the curable compound. This range increases the reaction rate of the (meth)acrylic compound, promoting rapid curing and eliminating the problem of interfacial peeling caused by an excessively fast reaction rate and increased contraction force.

[0083] The bifunctional (meth)acrylic compound, for example, a bifunctional (meth)acrylate having an alkylene glycol group, may be included in an amount of 40 to 90 parts by weight, for example, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, or 90 parts by weight, 40 to 80 parts by weight, or 50 to 80 parts by weight, based on 100 parts by weight of the (B) (meth)acrylic compound. Within this range, improvement in adhesive strength, reliability, and compatibility may be facilitated.

[0084] In one embodiment, the total amount of the monofunctional (meth)acrylic compound and the bifunctional (meth)acrylic compound may be 95 parts by weight or more, preferably 99 to 100 parts by weight, and more preferably 100 parts by weight, relative to 100 parts by weight of the (B) (meth)acrylic compound. Within this range, adhesive strength, reliability, and compatibility may be easily improved.

[0085] In one embodiment, the total amount of the monofunctional (meth)acrylate having an aromatic group and the bifunctional (meth)acrylate having an alkylene glycol group may be 95 parts by weight or more, preferably 99 to 100 parts by weight, and more preferably 100 parts by weight, relative to 100 parts by weight of the (meth)acrylic compound (B). Within this range, adhesive strength, reliability, and compatibility may be easily improved.

[0086] Photoinitiator The photoinitiator comprises a mixture of a photoacid generator and a photoacid generator.

[0087] The photoinitiator may be included in an amount of 1 to 15 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the curable compound. Within this range, the problem of the composition for the barrier layer not being cured and the problem of reduced light transmittance of the adhesive layer due to residual amounts remaining when an excessive amount is used can be resolved.

[0088] The photosensitizer may be a cyclohexyl phenyl ketone, a thioxanthone, or the like.

[0089] The photosensitizer may be included in an amount of 0.5 to 10 parts by weight, for example, 1 to 6 parts by weight, based on 100 parts by weight of the curable compound. Within this range, the composition for a barrier layer can be sufficiently cured, and problems such as reduced adhesion and bleeding out of the photosensitizer can be resolved.

[0090] The photoacid generator can contain an onium ion corresponding to the cation and an onium salt corresponding to the anion. Specific examples of the onium ion include diaryliodonium compounds such as diphenyliodonium, 4-methoxydiphenyliodonium, bis(4-methylphenyl)iodonium, bis(4-tert-butylphenyl)iodonium, bis(dodecylphenyl)iodonium, and (4-methylphenyl)[(4-(2-methylpropyl)phenyl)iodonium], triarylsulfonium compounds such as triphenylsulfonium, diphenyl-4-thiophenoxyphenylsulfonium, and diphenyl-4-(phenylthio)phenylsulfonium, bis[4-(diphenylsulfonio)phenyl]sulfide, bis[4-(di(4-(2-hydroxyethyl)phenyl)sulfonio)phenyl]sulfide, and 5-2,4-(cyclopentadienyl)[1,2,3,4,5,6-η]-(methylethyl)-benzene]-iron(1+). A specific example of an anion is tetrafluoroborate (BF4 - ), hexafluorophosphate (PF6 - ), hexafluoroantimonate (SbF6 - ), hexafluoroarsenate (AsF6 - ), hexachloroantimonate (SbCl6 - ) can be mentioned.

[0091] The photoacid generator may be included in an amount of 0.5 to 10 parts by weight, for example, 1 to 6 parts by weight, based on 100 parts by weight of the curable compound. Within this range, the composition for a barrier layer can be sufficiently cured, and problems such as a decrease in adhesive strength and bleeding out of the photoacid generator can be resolved.

[0092] Glycol compounds The glycol-based compound can enhance the low reactivity of the bisphenol-based epoxy compound. One feature of the barrier layer is that it uses a combination of glycol-based compounds to prevent the leaching of dichroic materials from the polarizer and enhance the low reactivity of the bisphenol-based epoxy compound. In this regard, the glycol-based compound may be included in an amount of 1 to 15 parts by weight, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 parts by weight, 1 to 10 parts by weight, or 5 to 10 parts by weight, based on 100 parts by weight of the bisphenol-based epoxy compound. This range can enhance the reactivity of the bisphenol-based epoxy compound and prevent a decrease in the reactivity of the (meth)acrylic compound.

[0093] The glycol-based compound may include one or more of ethylene glycol, propylene glycol, and 1,3-propanediol. For example, the glycol-based compound may be ethylene glycol.

[0094] The glycol compound may be included in an amount of 1 to 15 parts by weight, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 parts by weight, 1 to 10 parts by weight, or 1 to 7 parts by weight, relative to 100 parts by weight of the curable compound. Within this range, the reactivity of the bisphenol-type epoxy compound can be increased and a decrease in the reactivity of the (meth)acrylic compound can be prevented.

[0095] The composition may be prepared by mixing the curable compound, the photoinitiator, and the glycol-based compound. The composition may be a solvent-free composition, or may further contain a solvent to improve application properties (coatability).

[0096] The composition may further contain an antioxidant, an ultraviolet absorber, an ionic conductive agent, a conductivity-imparting additive such as conductive metal oxide fine particles, a light-diffusing additive, a viscosity adjuster, etc., within a range that does not impair the effects of the present invention.

[0097] The barrier layer may be formed by photocuring the composition, which may be carried out by a conventional method known to those skilled in the art.

[0098] The barrier layer may have a thickness of 0.1 μm to 10 μm, for example, 1 μm to 7 μm. The barrier layer in this range may be used in a polarizing plate.

[0099] Polarizer A polarizer can polarize external or internal light.

[0100] The polarizer may include a polyvinyl alcohol-based polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine or the like. For example, a polyvinyl alcohol-based polarizer is manufactured by dyeing a polyvinyl alcohol film with iodine or a dichroic dye and stretching the dye in a specific direction. Specifically, the polarizer is manufactured through a swelling process, a dyeing step, and a stretching step. Methods for performing each step are generally known to those skilled in the art.

[0101] The polarizer may have a thickness of 1 μm to 50 μm, and within this range, the polarizer can be used in a display device.

[0102] The polarizing plate may further include a retardation layer on at least one surface of the polarizer.

[0103] retardation layer The retardation layer prevents reflection of external light by circularly polarizing the linearly polarized light emitted after the external light passes through the polarizer, thereby realizing an anti-reflection function, thereby improving the appearance and screen quality.

[0104] In one embodiment, the retardation layer has an in-plane retardation of 100 to 220 nm, specifically 100 to 180 nm, for example, λ / 4 at a wavelength of 550 nm (first retardation layer). Within this range, the reflectance of external light can be reduced, and the screen quality can be improved.

[0105] In another specific example, the retardation layer may have an in-plane retardation of 225 nm to 350 nm, specifically 225 nm to 300 nm, for example, λ / 2 at a wavelength of 550 nm (second retardation layer). Within this range, the reflectance to external light can be reduced, and the screen quality can be improved.

[0106] In yet another specific example, the retardation layer may be a laminate of the first retardation layer and the second retardation layer.

[0107] In one embodiment, the retardation layer can exhibit reverse wavelength dispersion.

[0108] In one embodiment, the retardation layer may have a thickness of 0.1 μm to 10 μm, for example, 1 μm to 5 μm, which allows the polarizing plate to be thinned and achieve a desired retardation.

[0109] In one embodiment, the retardation layer may be a non-liquid crystal layer or a liquid crystal layer. Preferably, the retardation layer is a liquid crystal layer, which allows the polarizing plate to be made thinner.

[0110] For example, the liquid crystal retardation layer may be formed of a composition containing a liquid crystal compound having one or more of an aromatic functional group and an alicyclic functional group. In one embodiment, the liquid crystal compound may be a polymer, oligomer, or monomer containing a unit composed of an aromatic ring and a polymerizable functional group that can impart liquid crystallinity. The polymerizable functional group may be a (meth)acryloyl group, an epoxy group, a vinyl ether group, or the like, and may be cured by heat or light, thereby increasing the strength of the liquid crystal retardation layer.

[0111] The composition may be formed of a composition containing the aromatic-containing liquid crystal compound described above. The composition may further contain additives such as a leveling agent, a polymerization initiator, an alignment aid, a heat stabilizer, a lubricant, a plasticizer, and an antistatic agent, and the details of these additives may be found in those known to those skilled in the art.

[0112] The polarizing plate may further include a protective layer on at least one surface of the polarizer.

[0113] protective layer The protective layer may be formed on at least one surface of the polarizer to protect the polarizer or to provide an additional function to the polarizer.

[0114] The protective layer may include one or more of an optically transparent protective film and a protective coating layer.

[0115] When the protective layer is a protective film type, it may include a protective film formed of an optically transparent resin. The protective film may be formed by melting and extruding the resin. If necessary, a stretching process may be further added. The resin may include one or more of cellulose ester-based resins including triacetyl cellulose, cyclic polyolefin-based resins including cyclic olefin polymers (COP), polycarbonate-based resins, polyester-based resins including polyethylene terephthalate (PET), polyethersulfone-based resins, polysulfone-based resins, polyamide-based resins, polyimide-based resins, acyclic polyolefin-based resins, polyacrylate-based resins including polymethyl methacrylate resin, polyvinyl alcohol-based resins, polyvinyl chloride-based resins, and polyvinylidene chloride-based resins. Preferably, the protective film may be a film formed of a cyclic polyolefin-based resin including cyclic polyolefin.

[0116] When the protective layer is a protective coating layer type, it can have good adhesion to the polarizer, transparency, mechanical strength, thermal stability, moisture blocking properties, and durability. In one embodiment, the protective coating layer for the protective layer may be formed of an active energy ray-curable resin composition including an active energy ray-curable compound and a polymerization initiator.

[0117] The active energy ray-curable compound may include one or more of 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-based compound having at least one epoxy group in the molecule, or an oxetane-based compound having at least one oxetane ring in the molecule. The radically polymerizable curable compound may be a (meth)acrylic-based compound having at least one (meth)acryloyloxy group in the molecule.

[0118] The thickness of the protective layer is 5 μm to 200 μm, specifically 30 μm to 120 μm, and may be 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 layer type. The protective layer in this range can be used in an optical display device.

[0119] The protective layer may include a functional coating layer formed on at least one surface thereof or may be surface-treated. The functional coating layer may be, but is not limited to, a hard coating layer, an anti-fingerprint layer, an anti-reflection layer, a low-reflection layer, an ultra-low-reflection layer, an anti-glare layer, etc. The surface treatment may be, but is not limited to, a corona treatment.

[0120] The protective layer may be bonded to a polarizer or an adherend other than a polarizer by an adhesive layer. The adhesive layer may be formed of, but is not limited to, a water-based adhesive or a photo-curable adhesive. The water-based adhesive and the photo-curable adhesive may be appropriately used in accordance with the contents known to those skilled in the art.

[0121] The polarizing plate may include one or more adhesive layers, and the polarizing plate may include one or more adhesive layers, or two or more adhesive layers.

[0122] adhesive layer The adhesive layer can adhere the barrier layer to the retardation layer or the barrier layer to the protective layer.

[0123] In one embodiment, the adhesive layer may be a pressure sensitive adhesive (PSA). For example, the pressure sensitive adhesive layer may include a cured product of a composition including an adhesive resin and a curing agent.

[0124] 1 and 2 are cross-sectional views of a polarizing plate according to an embodiment.

[0125] Referring to FIG. 1, the polarizing plate may include a polarizer 100, a protective layer 200 laminated on the upper surface of the polarizer 100, a barrier layer 300 and a first retardation layer 400 sequentially laminated on the lower surface of the polarizer 100.

[0126] Referring to FIG. 2, the polarizing plate may include a polarizer 100, a protective layer 200 laminated on the upper surface of the polarizer 100, a barrier layer 300 sequentially laminated on the lower surface of the polarizer 100, a second retardation layer 500, an adhesive layer 600, and a first retardation layer 400.

[0127] Although not shown in FIGS. 1 and 2, the polarizing plate may further include one or more of a polarizer protective film, an anti-reflection film, a retardation film (liquid crystal layer or non-liquid crystal layer), and an adhesive film, which are commonly used in polarizing plates.

[0128] An optical display device according to an embodiment of the present invention includes the polarizing plate of the present invention. For example, the optical display device may be a light-emitting device display device having a light-emitting element, a liquid crystal display device, or the like.

[0129] The structure and operation of the present invention will be described in more detail below through preferred examples of the present invention, which are presented as preferred examples of the present invention and should not be construed as limiting the present invention in any way.

[0130] Example 1 (1) Preparation of the composition for the barrier layer

[0131] Alicyclic epoxy compounds, bisphenol epoxy compounds, and (meth)acrylate compounds are mixed in the amounts and types shown in Table 1 below to prepare 100 parts by weight of a curable compound.

[0132] 4 parts by weight of a glycol-based compound was added to 100 parts by weight of the prepared curable compound, and 4 parts by weight of a photoacid generator (Irgacure 250) and 1 part by weight of a photosensitizer (thioxanthone-based, DETX-S) were added and mixed to prepare a solventless composition for a barrier layer.

[0133] (2) Manufacture of polarizing plates A polyvinyl alcohol film (TS20, Mitsubishi Chemical Corporation, degree of polymerization: 2800, thickness: 20 μm) was immersed in a 0.3% potassium iodide aqueous solution to dye it, and then stretched in the machine direction (MD) at a uniaxial stretch ratio of 5.0. The stretched polyvinyl alcohol film was immersed in a 3% boric acid aqueous solution and a 2% potassium iodide aqueous solution to correct the color tone, and then dried at 50°C for 4 minutes to produce a polarizer (light transmittance: 45%, thickness: 7 μm).

[0134] As an upper polarizer protective film, a cyclic polyolefin film (thickness: 25 μm, Zeon) with a hard coating layer formed on its upper surface was prepared, and the lower surface of the film was subjected to corona treatment using a corona treater (AFS) at a speed of 10 mpm and an output of 1000 W.

[0135] As a lower polarizer protective film, a triacetyl cellulose film (thickness: 40 μm, Konica Minolta, normal TAC) was prepared without saponification treatment.

[0136] A polyvinyl alcohol resin (Z200, average degree of polymerization: 1200, degree of saponification: 98.5 mol%, contains acetoacetyl groups, degree of acetoacetylation: 5 mol%, Mitsubishi Chemical Corporation) was dissolved in water at 95°C for 60 minutes and then cooled completely to room temperature to produce a polyvinyl alcohol resin aqueous solution. Then, 0.1 parts by weight of a zirconium-containing crosslinker, Zircosol-ZN (Daiichi Kigenso Kagaku Kogyo Co., Ltd.), was added and mixed with 100 parts by weight of the polyvinyl alcohol resin aqueous solution to produce a water-based adhesive.

[0137] The aqueous adhesive was applied to both sides of the prepared polarizer to a predetermined thickness, and the upper polarizer protective film was attached to one side and a triacetyl cellulose-based film to the other side at the same time. The resulting film was dried at 80°C for 3 minutes, and then the triacetyl cellulose-based film was removed to expose the other side of the polarizer.

[0138] A λ / 2 liquid crystal retardation film (Fujifilm Corporation, a laminate of a λ / 2 liquid crystal retardation layer (thickness: 2 μm) and a substrate film) was prepared. The λ / 2 liquid crystal retardation layer side of the λ / 2 liquid crystal retardation film was subjected to corona treatment using a corona treater (AFS) at a speed of 10 mpm and an output of 1000 W.

[0139] The prepared barrier layer composition was applied to the λ / 2 liquid crystal retardation layer side of the λ / 2 liquid crystal retardation film to a thickness of about 3 μm, and then laminated to the other side of the polarizer. Then, a metal halide lamp was placed on the substrate film side of the λ / 2 liquid crystal retardation film, and a UVA light of about 1000 mJ / cm was applied. 2 The composition for a barrier layer was cured by irradiating the film with light at a light intensity of 1000 kJ / cm, thereby forming a barrier layer, and the base film was then removed.

[0140] A λ / 4 liquid crystal retardation film (Fujifilm Corporation, a laminate of a λ / 4 liquid crystal retardation layer (thickness: 1 μm) and a substrate film) was prepared. The λ / 4 liquid crystal retardation layer side of the λ / 4 liquid crystal retardation film was subjected to corona treatment using a corona treater (AFS) at a speed of 10 mpm and an output of 1000 W.

[0141] The prepared barrier layer composition was applied to the λ / 4 liquid crystal retardation layer side to a thickness of about 3 μm, and then laminated with the λ / 2 liquid crystal retardation layer. A metal halide lamp was placed on the substrate film side of the λ / 4 liquid crystal retardation film, and about 1000 mJ / cm 2 was irradiated based on UVA. 2 The barrier layer composition was cured by irradiating the film with light at a light intensity of 1000 W / m to form a barrier layer. The substrate film was then removed to produce a polarizing plate having an upper polarizer protective film-aqueous adhesive layer-polarizer-barrier layer-λ / 2 liquid crystal retardation layer-barrier layer-λ / 4 liquid crystal retardation layer laminated in this order.

[0142] The polarizing plate was manufactured at 22°C to 25°C and a relative humidity of 20% to 60%.

[0143] Examples 2 to 5 A polarizing plate was manufactured in the same manner as in Example 1, except that the content of each component in the composition for the barrier layer in Example 1 was changed as shown in Table 1 below.

[0144] Comparative Examples 1 to 6 A polarizing plate was manufactured in the same manner as in Example 1, except that the content of each component in the composition for the barrier layer in Example 1 was changed as shown in Table 1 below.

[0145] The polarizing plates manufactured in the examples and comparative examples were evaluated for physical properties as shown in Table 1 below, and the results are shown in Table 1 below.

[0146] (1) Affinity for iodine: The barrier layer composition used above was applied to a thickness of 6 μm between a cyclic polyolefin (COP) film (Zeon Corporation) and a polyethylene terephthalate film (thickness: 40 μm to 60 μm) using a dropper. Then, a metal halide lamp was used to apply 1000 mJ / cm2 based on UVA. 2 The composition was cured by irradiating the light at an integrated dose of 1000 times, and then the COP film was removed to prepare a test piece of a barrier layer / PET film.

[0147] The prepared specimen was cut into a square measuring 50 mm x 50 mm and completely immersed in the 0.3% potassium iodide aqueous solution used in preparing the polarizer and left at 60°C for 2 hours. The specimen was then removed and washed with distilled water, and the yellow index of the specimen was measured in transmission mode using a colorimeter (CM-3600A, Konica Minolta). A lower yellow index indicates a lower affinity of the barrier layer for iodine and indicates that the barrier layer can provide a barrier effect against iodine leached from the polarizer.

[0148] (2) Change in corrosion resistance after high temperature and humidity The polarizers prepared in the examples and comparative examples were cut to a length x width (65 mm x 25 mm) and bonded to the ITO surface of an ITO film (thickness: 125 μm, 60 Ω) using an acrylic adhesive layer. Silver paste was applied to the bonded sample, dried at 40°C for 1 hour, and then left at room temperature for 1 hour to prepare a test specimen (Figure 3). Referring to Figure 3, the test specimen includes an ITO film 31, a polarizer 32, and six measurement points 33 formed with silver paste. The initial resistance (R0) was measured using a two-terminal multimeter. The test specimen was then placed in a chamber at 60°C and 95% relative humidity and left for 500 hours, then removed and left at 25°C for 1 hour. The resistance (R1) was measured using the same method as above. The resistance change was calculated as |R1 - R0|. A lower resistance change indicates that the barrier layer provides a better barrier effect against iodine leaching from the polarizer.

[0149] ○: Resistance change is 100Ω or less △: Resistance change is over 100Ω and 500Ω or less ×: Resistance change exceeds 500Ω (3) Change in light transmittance after high temperature and humidity

[0150] The polarizing plates prepared in the Examples and Comparative Examples were cut into squares measuring 25 mm x 25 mm with the absorption axis of the polarizer at a 45° angle. Test specimens were then attached to glass plates (25 mm x 100 mm) using an acrylic adhesive layer. The initial light transmittance (T0) of the test specimens was measured using a V-7170 (JASCO). The test specimens were placed in a chamber at 60°C and 95% relative humidity and left for 500 hours, then removed and left at 25°C for 1 hour. The light transmittance (T1) was measured using a V-7170 in the same manner as above. The change in light transmittance was calculated as |T1 - T0|.

[0151] ○: Change in light transmittance is 2% or less △: Change in light transmittance is more than 2% but less than 3% ×: The change in light transmittance exceeds 3%

[0152] (4) Bleaching after high temperature and humidity The polarizing plates manufactured in the examples and comparative examples were cut into 50mm x 50mm squares with the absorption axis of the polarizer at a 45° angle, and then attached to glass plates using an acrylic adhesive layer to prepare test specimens. The specimens were placed in a chamber at 60°C and 95% relative humidity for 500 hours and then removed. The length 42 of the test specimen 41 where iodine discoloration occurred was measured diagonally from each of the four corners of the specimen, as shown in Figure 4, and the level was classified as follows:

[0153] ◎: Less than 1mm ○: 1mm or more and less than 2mm △: 2mm or more and less than 3mm ×: 3mm or more

[0154] (5) Flexural reliability after high temperature and humidity The polarizing plates manufactured in the Examples and Comparative Examples were cut into 50 mm x 50 mm squares with the absorption axis of the polarizer at a 45° angle. They were folded in half to create 3R and 1R radii of curvature, and then placed between two slits (51: 3R radius of curvature, 52: 1.5R radius of curvature) with the fixed shapes shown in Figure 5. The plates were then placed in a chamber at 60°C and 95% relative humidity and left for 500 hours before being removed. The presence of bubbles, wrinkles, or wavy lines at the folded portion due to the lifting of the interlayer interface was visually evaluated. A complete absence of bubbles, wrinkles, or wavy lines was evaluated as "good," while even slight bubbles, wrinkles, or wavy lines were evaluated as "poor."

[0155] [Table 1]

[0156] A) Bis(3,4-epoxycyclohexylmethyl) adipate (Tetra) B) 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate modified ε-caprolactone (Daicel) C) Bisphenol A epoxy compound (YD128, Kukdo Chemical Co., Ltd.) D) Bisphenol F epoxy compound (YDF170, Kukdo Chemical Co., Ltd.) E) Dipropylene glycol diacrylate (Miwon) F) Benzyl acrylate (Miwon) G) Ethylene glycol H) Novolac-type epoxy compounds I) Ethanol

[0157] As shown in Table 1 above, the polarizing plates of the examples have low iodine affinity, so they can sufficiently prevent corrosion due to iodine elution, ensure hardness, and achieve a barrier effect that prevents moisture-resistant discoloration due to residual monomers.

[0158] Simple variations and modifications of the present invention can be easily implemented by those skilled in the art, and all such variations and modifications can be considered to be included within the scope of the present invention. [Explanation of symbols]

[0159] 100 Polarizer 200 protective layer 300 Barrier Layer 400 1st retardation layer

Claims

1. a polarizer and a barrier layer formed on one surface of the polarizer, the barrier layer comprises: a curable compound including an epoxy compound, such as an alicyclic epoxy compound and a bisphenol epoxy compound, and a (meth)acrylic compound; a photoinitiator; and a glycol compound; The bisphenol-type epoxy compound is included in an amount of 20 to 70 parts by weight based on 100 parts by weight of the curable compound, A polarizing plate comprising a cured product of a composition in which the glycol-based compound is contained in an amount of 1 to 15 parts by weight based on 100 parts by weight of the curable compound.

2. The polarizing plate of claim 1 , wherein the bisphenol epoxy compound comprises at least one of a bisphenol A epoxy compound, a bisphenol F epoxy compound, and a bisphenol S epoxy compound.

3. 2. The polarizing plate according to claim 1, wherein the glycol-based compound includes at least one of ethylene glycol, propylene glycol, and 1,3-propanediol.

4. 2. The polarizing plate of claim 1, wherein the glycol compound is contained in an amount of 1 to 15 parts by weight based on 100 parts by weight of the bisphenol epoxy compound.

5. 2. The polarizing plate according to claim 1, wherein the alicyclic epoxy compound has a main chain of a linear or branched alkylene group having 4 or more carbon atoms between two alicyclic epoxy groups.

6. 2. The polarizing plate according to claim 1, wherein the alicyclic epoxy compound comprises a compound represented by the following Chemical Formula 2: 【Chemistry 1】 (In the above Chemical Formula 2, R １ , R ３ each independently represents a single bond or a linear or branched alkylene group having 1 to 5 carbon atoms, X １ , X ２ are each independently —O—C(═O)— or —C(═O)—O—, R ２ is a linear or branched alkylene group having 4 or more carbon atoms, n is an integer of 1 or more, R ４ , R ５ are each independently an alkyl group having 1 to 5 carbon atoms, a and b are each independently an integer of 0 to 9.

7. 2. The polarizing plate according to claim 1, wherein the alicyclic epoxy compound includes at least one of bis(3,4-epoxycyclohexylmethyl)adipate and 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate modified ε-caprolactone.

8. The polarizing plate according to claim 1 , wherein the (meth)acrylic compound comprises a mixture of a monofunctional (meth)acrylic compound and a difunctional (meth)acrylic compound.

9. 9. The polarizing plate according to claim 8, wherein the monofunctional (meth)acrylic compound:difunctional (meth)acrylic compound content in the mixture is in a weight ratio of 1:1 to 1:

3.

10. 9. The polarizing plate according to claim 8, wherein the monofunctional (meth)acrylic compound includes a (meth)acrylate having an aromatic group, and the bifunctional (meth)acrylic compound includes a bifunctional (meth)acrylate having an alkylene glycol group.

11. 11. The polarizing plate according to claim 10, wherein the (meth)acrylate having an aromatic group includes one or more of benzyl (meth)acrylate and phenoxyethyl (meth)acrylate, and the bifunctional (meth)acrylate having an alkylene glycol group includes one or more of diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, and tripropylene glycol di(meth)acrylate.

12. The curable compound is 1 to 50 parts by weight of the alicyclic epoxy compound, 20 to 70 parts by weight of the bisphenol-type epoxy compound, and The polarizing plate according to claim 1 , comprising the curable compound containing 20 to 70 parts by weight of the (meth)acrylic compound.

13. 10. The polarizer of claim 1, wherein the photoinitiator comprises a mixture of a photoacid generator and a photosensitizer.

14. The polarizing plate according to claim 1 , further comprising a liquid crystal retardation layer.

15. As the composition for the barrier layer, a curable compound including an epoxy compound including an alicyclic epoxy compound and a bisphenol epoxy compound, and a (meth)acrylic compound; a photoinitiator; and a glycol compound; The bisphenol-type epoxy compound is included in an amount of 20 to 70 parts by weight based on 100 parts by weight of the curable compound, The composition for a barrier layer, wherein the glycol-based compound is contained in an amount of 1 to 15 parts by weight based on 100 parts by weight of the curable compound.

16. The composition for a barrier layer according to claim 15, wherein the glycol-based compound includes one or more of ethylene glycol, propylene glycol, and 1,3-propanediol.

17. The composition for a barrier layer according to claim 15, wherein the glycol-based compound is contained in an amount of 1 to 15 parts by weight based on 100 parts by weight of the bisphenol-type epoxy-based compound.

18. The composition for a barrier layer according to claim 15 , wherein the (meth)acrylic compound comprises a mixture of a monofunctional (meth)acrylic compound and a difunctional (meth)acrylic compound.

19. The curable compound is 1 to 50 parts by weight of the alicyclic epoxy compound, 20 to 70 parts by weight of the bisphenol-type epoxy compound, and The composition for a barrier layer according to claim 15, comprising 20 to 70 parts by weight of the (meth)acrylic compound.

20. A display device comprising the polarizing plate according to claim 1 .

Images