KR20200078183A - Acryl-based adhesive composition, polarizing plate and display device - Google Patents

Abstract

Provided are an acryl-based adhesive composition, a polarizing plate, and a display device, capable of implementing excellent durability. The present invention relates to an acryl-based adhesive composition, and a polarizing plate and a display device manufactured by using the same, in which the acryl-based adhesive composition includes an acryl-based copolymer formed by polymerizing a monomer mixture including a monomer represented by chemical formula 1, an alkyl (meth)acrylate-based monomer, and a (meth)acryl-based monomer having a crosslinkable functional group, wherein the monomer mixture includes 10 to 20 parts by weight of the monomer represented by chemical formula 1 based on 100 parts by weight of the monomer mixture, and a polymerization conversion rate of the acryl-based copolymer is 50 % or less. In chemical formula 1, R^1 and R^2 are independently hydrogen or a C1-C4 alkyl group, and A is a single bond, a C1-C4 alkylene group, ether, ester, or a combination thereof.

Description

ACRYL-BASED ADHESIVE COMPOSITION, POLARIZING PLATE AND DISPLAY DEVICE}

The present invention relates to an acrylic pressure-sensitive adhesive composition, a polarizing plate and a display device, and more specifically, durability, particularly excellent durability at room temperature and low-humidity conditions, and an acrylic pressure-sensitive adhesive composition with little change over time after formation of the pressure-sensitive adhesive layer and a polarizing plate produced using the same And a display device.

In general, a liquid crystal display device (LCD) is provided with a liquid crystal cell and a polarizing plate containing liquid crystal, and an adhesive layer is used to attach the liquid crystal cell and the polarizing plate. As the adhesive for attaching the polarizing plate forming the adhesive layer, acrylic resin, rubber, urethane resin, silicone resin, or EVA (Ethylene Vinyl Acetate) is used. Among them, acrylic resin having transparency, oxidation resistance and yellowing resistance is used as a base. A lot of pressure-sensitive adhesives are used.

In the case of the acrylic adhesive for polarizing plates, it is preferable to use an acrylic resin having a high weight average molecular weight in order to improve durability and curing efficiency. This is because when an acrylic resin having a low weight average molecular weight is used, curing efficiency is lowered and the curing speed is slowed, and the cohesive strength and curing degree of the pressure-sensitive adhesive are lowered under high temperature or high temperature/high humidity conditions, thereby reducing durability. However, when an acrylic resin having a high weight average molecular weight is used, there is a problem in that the viscosity of the coating solution increases and the workability decreases. It is possible to control the viscosity of the coating liquid by lowering the solid content in the coating liquid.However, in the case of forming the adhesive layer using the coating liquid having a low solid content, the production cost increases and productivity decreases, and it is difficult to precisely control the thickness of the adhesive layer. There is a problem.

In order to solve this problem, conventionally, an acrylic resin having a low weight average molecular weight having relatively low viscosity properties is used, but an acrylic resin is prepared by adding a monomer having a crosslinkable functional group such as a hydroxyl group or a carboxy group, and the acrylic system A method of improving the durability of the adhesive layer by mixing a resin with a curing agent to form a crosslinked structure between polymer chains through reaction of the curing agent with a crosslinkable functional group during coating has been proposed. However, in the case of such a conventional method, even after the adhesive layer is formed, the crosslinking reaction proceeds slowly by the remaining curing agent, and the peeling force of the adhesive layer decreases with the passage of time by this additional crosslinking reaction. Therefore, problems such as deterioration of polarizer durability occur.

Therefore, there is a need to develop an acrylic pressure-sensitive adhesive composition capable of realizing excellent durability with little change over time after forming the pressure-sensitive adhesive layer.

The present invention is to solve the above problems, and to provide an acrylic pressure-sensitive adhesive composition that has little change over time after formation of the adhesive layer and can realize excellent durability.

In addition, the present invention is to provide a polarizing plate comprising an adhesive layer formed by the acrylic pressure-sensitive adhesive composition as described above and a display device including the same.

In one aspect, the present invention is an acrylic copolymer formed by polymerizing a monomer mixture comprising a monomer represented by the following [Formula 1], an alkyl (meth)acrylate monomer and a (meth)acrylic monomer having a crosslinkable functional group. It is an acrylic pressure-sensitive adhesive composition comprising, the monomer mixture, the monomer represented by the [Formula 1] comprises 10 to 20 parts by weight relative to 100 parts by weight of the monomer mixture, the polymerization conversion rate of the acrylic copolymer is 50% or less An acrylic pressure-sensitive adhesive composition is provided.

[Formula 1]

In Formula 1, R1 and R2 are each independently hydrogen or a C1 to C4 alkyl group, and A is a single bond, a C1 to C4 alkylene group, ether, ester, or a combination thereof.

In another aspect, the present invention is a polarizing film; And it is formed on one or both sides of the polarizing film, and provides a polarizing plate comprising an adhesive layer comprising a cured product of the acrylic pressure-sensitive adhesive composition according to the present invention.

In another aspect, the present invention provides a display device including the polarizing plate according to the present invention.

The acrylic pressure-sensitive adhesive composition according to the present invention includes an acrylic copolymer having a branched polymer structure prepared by polymerizing a monomer mixture containing a monomer represented by Chemical Formula 1, even when the solid content in the coating solution is higher than 30% by weight. Since the viscosity can be realized, the coating layer is excellent in forming the adhesive layer, has high productivity, and can accurately control the thickness of the adhesive layer.

In addition, the acrylic pressure-sensitive adhesive composition according to the present invention by using an acrylic copolymer having a low polymerization conversion rate using an unsaturated hydrocarbon functional group remaining in the copolymer to allow the additional crosslinking reaction to proceed during the formation of the adhesive layer, compared with the conventional curing agent amount It can be significantly reduced, and accordingly it is possible to effectively suppress the occurrence of change over time in the adhesive layer due to the unreacted curing agent.

In addition, the polarizing plate comprising the adhesive layer formed by using the acrylic pressure-sensitive adhesive composition according to the present invention has very low change over time in the adhesive layer, and exhibits excellent durability under high temperature and high temperature/high humidity conditions as well as at low temperature and normal humidity conditions.

Hereinafter, the present invention will be described in detail.

When'include','have','consist of', etc. mentioned in this specification are used, other parts may be added unless'~man' is used. When a component is expressed as a singular number, the plural number is included unless otherwise specified.

In interpreting the components, it is interpreted as including the error range even if there is no explicit description.

In this specification, "(meth)acrylic" is a generic term for acrylic and methacrylic. For example, (meth)acrylate includes methacrylate and acrylate, and (meth)acrylic acid includes acrylic acid and methacrylic acid.

In this specification, "X to Y" indicating a range means "X or more and Y or less".

In the present specification, "branched polymer structure" means a polymer structure having two or more long chains grown in different directions.

Adhesive composition

First, the acrylic pressure-sensitive adhesive composition according to the present invention will be described.

(1) Acrylic copolymer

The acrylic pressure-sensitive adhesive composition according to the present invention is an acrylic copolymer formed by polymerizing a monomer mixture comprising a monomer represented by the following [Formula 1], an alkyl (meth)acrylate monomer, and a (meth)acrylic monomer having a crosslinkable functional group. Includes coalescence.

[Formula 1]

In Formula 1, R1 and R2 are each independently hydrogen, or a C1 to C4 alkyl group, and may be preferably hydrogen, methyl, or ethyl.

The A may be a single bond, a C1 to C4 alkylene group, an ether, an ester, or a combination thereof, preferably, a C1 to C4 alkylene group or a C1 to C4 oxyalkylene group. If the length of the carbon chain of the A is too long, it is difficult to achieve a desired level of weight average molecular weight when polymerizing the acrylic copolymer, and crosslinking reaction is not smoothly performed when coating the adhesive layer, so the physical properties of the adhesive layer may be deteriorated. have.

The monomer represented by [Formula 1] is to form a crosslinked structure in the adhesive layer forming process, and to form a branched polymer, for example, allyl methacrylate, allyl acrylate ), methalyl methacrylate, methalyl acrylate, 3-butenyl acrylate, but-3-enyl-2-methylprop-2-enoate (but-3-enyl-2-methylprop-2-enoate), 2-allyloxyethyl acrylate, 2-allyloxyethyl methacrylate, 3-allyloxypropyl 3-allyloxypropyl methacrylate, 3-allyloxypropyl acrylate, 2-allyloxyethoxyethyl methacrylate, and 2-allyloxyethoxyethyl acrylate ) May be one or more selected from the group consisting of, but is not limited thereto.

Conventionally, acrylic copolymers having a linear polymer structure in which monomers are polymerized in a long chain form are mainly used as acrylic copolymers used for adhesives for polarizing plates. However, when using acrylic copolymers having such a linear structure, there was a problem in that the viscosity increases and the workability deteriorates as the weight average molecular weight increases.

However, since the monomer of [Formula 1] has two or more ethylene groups, radical formation is possible in free radical polymerization, and because of this, chains can be grown in different directions. Branched polymer having a will be formed. Since the acrylic copolymer having a branched polymer structure has a lower viscosity characteristic than the acrylic copolymer having a linear polymer structure having the same weight average molecular weight, it is possible to realize excellent coating properties even when the solid content in the coating solution is increased.

In addition, some of the unsaturated hydrocarbon groups included in the monomer represented by [Formula 1] do not react in the polymerization process and remain in the copolymer, and then react with heat in the adhesive layer forming process (coating process) to cross-link structure To form. Therefore, when the monomer represented by [Chemical Formula 1] is included as described above, there is no need to excessively include a curing agent for forming the internal crosslinked structure of the pressure-sensitive adhesive composition.

The monomer represented by [Formula 1], 10 to 20 parts by weight based on 100 parts by weight of the monomer mixture, preferably 12 to 18 parts by weight may be included. If the content of the monomer represented by [Chemical Formula 1] is less than 10 parts by weight, the desired level of durability cannot be obtained at room temperature and low humidity, and when it exceeds 20 parts by weight, the polymerization reaction proceeds too quickly and gelation proceeds during the polymerization process. And cannot be used as an adhesive.

Meanwhile, the alkyl (meth)acrylate-based monomer preferably contains an alkyl group having 2 to 14 carbon atoms. This is because when the alkyl group included in the alkyl (meth)acrylate monomer is too long, the cohesive force of the pressure-sensitive adhesive decreases, and it may be difficult to control the glass transition temperature (Tg) or adhesion. For example, examples of the alkyl (meth)acrylate-based monomer include ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, sec-butyl (meth)acrylate, pentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, n-octyl (meth) )Acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, lauryl (meth)acrylate and tetradecyl (meth)acrylate. In the present invention, one or more of the above mixtures are mixed. Can be used.

The alkyl (meth)acrylate-based monomer may be included in an amount of 79 parts by weight to 89.99 parts by weight, preferably 81.50 to 87.99 parts by weight based on 100 parts by weight of the monomer mixture. When the content of the alkyl (meth)acrylate-based monomer satisfies the above range, excellent adhesion and durability can be obtained.

Next, the (meth)acrylic monomer having the crosslinkable functional group is for improving the adhesion between the pressure-sensitive adhesive and the substrate. Conventionally, it was common to use a (meth)acrylic monomer having a crosslinkable functional group in order to improve the cohesive force for elasticity of the adhesive, but the acrylic copolymer of the present invention can exhibit sufficient cohesion even without adding a crosslinkable functional group. . Therefore, in the present invention, a (meth)acrylic monomer having a small amount of a crosslinkable functional group is used for the purpose of improving the adhesion between the pressure-sensitive adhesive and the substrate.

As the (meth)acrylic monomer having the crosslinkable functional group, for example, a hydroxy group-containing monomer, a carboxyl group-containing monomer, or a nitrogen-containing monomer may be used, but is not limited thereto. Specific examples of the hydroxy group-containing monomer in the above, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth )Acrylate, 8-hydroxyoctyl (meth)acrylate, 2-hydroxyethylene glycol (meth)acrylate or 2-hydroxypropylene glycol (meth)acrylate, etc., and examples of the carboxyl group-containing monomer (Meth)acrylic acid, 2-(meth)acryloyloxy acetic acid, 3-(meth)acryloyloxy propyl acid, 4-(meth)acryloyloxy butyric acid, acrylic acid doublets, itaconic acid, maleic acid And maleic anhydride, and examples of the nitrogen-containing monomer include (meth)acrylamide, N-vinyl pyrrolidone, or N-vinyl caprolactam, but are not limited thereto.

The (meth)acrylic monomer having the crosslinkable functional group may be included in an amount of 0.01 to 1 part by weight, preferably 0.01 to 0.5 part by weight based on 100 parts by weight of the monomer mixture. When the content of the (meth)acrylic monomer having a crosslinkable functional group satisfies the above range, adhesion to the substrate is excellent.

According to one embodiment, the (meth) acrylic copolymer, based on 100 parts by weight of the monomer mixture, 79 parts by weight to 89.99 parts by weight of the alkyl (meth) acrylate-based monomer, 0.01 to 1 part by weight of a crosslinkable functional group ( It may be formed by polymerizing a monomer mixture comprising a meth)acrylic monomer and a monomer represented by 10 to 20 parts by weight of [Formula 1].

The acrylic copolymer according to the present invention can be prepared by mixing each of the monomers described above to prepare a monomer mixture and then polymerizing it. At this time, the polymerization reaction is terminated when the polymerization conversion rate reaches 50% or less, preferably 30 to 50%, more preferably 40 to 50%. Since the present invention includes a monomer represented by [Formula 1] in a high content of 10 to 20 parts by weight, when the polymerization conversion rate exceeds 50%, the viscosity may increase and coating properties may be deteriorated. On the other hand, when the polymerization conversion rate is less than 10%, it is difficult to implement durability.

The acrylic copolymer of the present invention prepared as described above has a weight average molecular weight of 300,000 to 500,000 g/mol, preferably 400,000 to 500,000 g/mol. When the weight average molecular weight of the acrylic copolymer is less than 300,000 g/mol, the crosslinked structure is not sufficiently formed when the adhesive layer is formed, and durability may be deteriorated. When the weight average molecular weight exceeds 500,000 g/mol, gelation occurs. Therefore, coating properties may be deteriorated.

Meanwhile, the polymerization method is not particularly limited, and various polymerization methods known in the art, for example, polymerization methods such as solution polymerization, photo polymerization, bulk polymerization, suspension polymerization or emulsion polymerization, may be used. During the polymerization, a polymerization initiator, molecular weight control, and the like may be additionally added, and the timing of inputting each component is not particularly limited. That is, the components may be input in batches, or may be divided into multiple inputs.

In the present invention, in particular, an acrylic copolymer may be prepared using a solution polymerization method, and solution polymerization is performed by adding a polymerization initiator in a state in which each monomer is uniformly mixed, and performing the polymerization at 50°C to 140°C. desirable. Examples of initiators that can be used in this process include azo-based initiators such as azobisisobutyronitrile or azobiscyclohexane carbonitrile; And/or common initiators such as peroxides such as benzoyl peroxide or acetyl peroxide, and a mixture of one or more of the above may be used, but is not limited thereto. In addition, as the molecular weight modifier, mercaptans such as t-dodecyl mercaptan or n-dodecyl mercaptan, dipentine, or terpenes of t-terpene, chloroform, or halogenated hydrocarbons of carbon tetrachloride, or pentaerythritol Tetrakis (3-mercapto propionate) may be used, but is not limited thereto.

In addition, the acrylic copolymer of the present invention has a branched (branched) polymer structure. Since the acrylic copolymer having a branched polymer structure has a lower viscosity characteristic than a linear acrylic copolymer having the same weight average molecular weight, the pressure-sensitive adhesive composition containing the same can realize excellent coating properties even when the solid content is high.

(2) Multifunctional Hardener

Meanwhile, the pressure-sensitive adhesive composition of the present invention may further include a multifunctional curing agent together with the acrylic copolymer.

The multifunctional curing agent is for improving the interfacial adhesion with the substrate, the type is not particularly limited, various curing agents used in the art, for example, isocyanate-based compounds, epoxy-based compounds, aziridine-based compounds, and One or more kinds selected from the group consisting of metal chelating compounds may be used.

As the isocyanate-based compound, a conventional one known in the art can be used, for example, toluene diisocyanate, 2,4-trilene diisocyanate, 2,6-trilene diisocyanate, hydrogenated triylene diisocyanate, Isoform diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane-4,4-diisocyanate, 1,3-bisisocyanatomethyl cyclohexane, tetramethylxylene diisocyanate, 1 ,5-Naphthalene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethyl hexamethylene diisocyanate, 2,4,4-trimethyl hexamethylene diisocyanate, trimethylolpropane modified toluene diisocyanate, trimethylolpropane modified tolylene Diisocyanate, trimethylolpropane's trilene diisocyanate adduct, trimethylolpropane's xylene diisocyanate adduct, toriphenylmethanetoriisocyanate, methylene bis triisocyanate, their polyols (trimethylolpropane) or mixtures thereof Can be used.

Examples of the epoxy compound include ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, N,N,N',N'-tetraglycidylethylenediamine, and glycerin Diglycidyl ether or mixtures thereof can be used.

Examples of the aziridine-based compound include N,N'-toluene-2.4-bis(1-aziridinecarboxamide) and N,N'-diphenylmethane-4,4'-bis(1-aziri) Deancarboxamide), triethylene melamine, bisisopropaloyl-1-(2-methylaziridine), tri-1-aziridinylphosphine oxide, or mixtures thereof.

Examples of the metal chelating compound include, for example, a compound in which a polyvalent metal such as aluminum, iron, zinc, tin, titanium, antimony, magnesium, and/or vanadium coordinates acetyl acetone or ethyl acetoacetate, and the like. , But is not limited thereto.

The multifunctional curing agent is preferably included in 0.001 to 0.1 parts by weight based on 100 parts by weight of the acrylic copolymer. In the case of the acrylic pressure-sensitive adhesive composition of the present invention, an unsaturated hydrocarbon group remaining inside the acrylic copolymer reacts to form a crosslinked structure when the adhesive layer is formed, so it is not necessary to include an excessive amount of a curing agent to form the crosslinked structure, and It contains only a small amount of curing agent for the purpose of improving interfacial adhesion. When the content of the polyfunctional curing agent is less than 0.001 part by weight, the effect of improving adhesion to the substrate is negligible, and when it exceeds 0.1 part by weight, a change in the physical properties of the adhesive may occur. As described above, since the pressure-sensitive adhesive composition according to the present invention contains a very small amount of the multifunctional curing agent, the change over time in the physical properties of the pressure-sensitive adhesive layer due to the residual curing agent is effectively suppressed.

(3) Other ingredients

The pressure-sensitive adhesive composition of the present invention may further include a solvent, a silane coupling agent, a tackifying resin, an additive, and other components, in addition to the above-mentioned components for controlling physical properties.

The pressure-sensitive adhesive composition of the present invention may further include a solvent for adjusting the viscosity. The solvent may be a polymerization solvent used in the process of preparing an acrylic copolymer, or may be a diluting solvent added for viscosity adjustment as necessary. Examples of the solvent include ethyl acetate, n-pentane, isopentane, neopentane, n-hexane, n-octane, n-heptane, methyl ethyl ketone, acetone, toluene, or combinations thereof. It is not limited to this. The solvent may be included in an amount such that the solid content in the pressure-sensitive adhesive composition is 30% by weight or more, preferably 30 to 60% by weight.

The pressure-sensitive adhesive composition of the present invention may further include a silane coupling agent. The silane coupling agent improves adhesion and adhesion stability between the pressure-sensitive adhesive and the glass substrate, improves heat resistance and moisture resistance, and also improves adhesion reliability when the pressure-sensitive adhesive is left for a long time under high temperature and/or high humidity conditions. . Examples of coupling agents that can be used in the present invention include γ-glycidoxypropyl triethoxy silane, γ-glycidoxypropyl trimethoxy silane, γ-glycidoxypropyl methyldiethoxy silane, and γ-glycidoxy. Propyl triethoxy silane, 3-mercaptopropyl trimethoxy silane, vinyltrimethoxysilane, vinyltriethoxy silane, γ-methacryloxypropyl trimethoxy silane, γ-methacryloxypropyl triethoxy silane, γ-aminopropyl trimethoxy silane, γ-aminopropyl triethoxy silane, 3-isocyanato propyl triethoxy silane, γ-acetoacetatepropyl trimethoxysilane, γ-acetoacetatepropyl triethoxy silane, and β-cyanoacetyl trimethoxy silane, β-cyanoacetyl triethoxy silane, and acetoxyaceto trimethoxy silane. One or a mixture of two or more of the above can be used. In the present invention, it is preferable to use a silane coupling agent having an acetoacetate group or a β-cyanoacetyl group, but it is not limited thereto. In the composition of the present invention, the silane coupling agent may be included in an amount of 0.01 to 5 parts by weight, preferably 0.01 to 1 part by weight based on 100 parts by weight of the acrylic copolymer. If the content of the coupling agent is less than 0.01 part by weight, the effect of increasing the adhesion is negligible, and when it exceeds 5 parts by weight, there is a fear that durability is deteriorated.

The pressure-sensitive adhesive composition of the present invention may further include 1 part by weight to 100 parts by weight of a tackifying resin with respect to 100 parts by weight of the acrylic copolymer, from the viewpoint of control of the adhesion performance. The type of the tackifying resin is not particularly limited, for example, (hydrogenated) hydrocarbon resin, (hydrogenated) rosin resin, (hydrogenated) rosin ester resin, (hydrogenated) terpene resin, (hydrogenated) terpene phenol resin, It is possible to use one kind or a mixture of two or more kinds such as a polymerized rosin resin or a polymerized rosin ester resin. When the content of the tackifying resin is less than 1 part by weight, the addition effect may be insignificant, and when it exceeds 100 parts by weight, the effect of improving compatibility and/or cohesion may be lowered.

The pressure-sensitive adhesive composition of the present invention is also one or more additives selected from the group consisting of epoxy resins, curing agents, ultraviolet stabilizers, antioxidants, colorants, reinforcing agents, fillers, antifoaming agents, surfactants, and plasticizers, within a range not affecting the effects of the invention It may further include.

The acrylic pressure-sensitive adhesive composition according to the present invention uses an acrylic copolymer having a low polymerization conversion rate, thereby allowing an additional crosslinking reaction to proceed when forming the pressure-sensitive adhesive layer using an unsaturated hydrocarbon functional group remaining in the copolymer, thereby significantly increasing the amount of curing agent used compared to the prior art. Accordingly, it is possible to effectively suppress the occurrence of change over time in the adhesive layer due to the unreacted curing agent.

In addition, the acrylic pressure-sensitive adhesive composition according to the present invention has a low polymerization conversion rate, and uses an acrylic copolymer having a branched polymer structure, compared to an adhesive composition using an acrylic copolymer having a linear polymer structure having the same weight average molecular weight. Low viscosity can be achieved. Specifically, the pressure-sensitive adhesive composition according to the present invention has a solids content of 30% by weight or more, for example, 30% by weight to 60% by weight of a viscosity at 23°C of 3,000cP or less, preferably 500cP to 3,000cP, More preferably, it appears as low as 500 cP to 2,000 cP. At this time, the solid content may refer to the solid content at the time when the pressure-sensitive adhesive composition of the present invention is prepared in the form of a coating liquid or the like and applied to the manufacturing process of the pressure-sensitive adhesive composition. As described above, when the pressure-sensitive adhesive composition of the present invention is used, it is possible to increase the solid content in the coating solution without deteriorating the coating property, and not only has excellent productivity, but also allows precise control of thickness and the like.

On the other hand, in the case of the conventional acrylic adhesive composition, an acrylic copolymer having a high weight average molecular weight was used to implement physical properties such as durability, and the adhesive composition containing such an acrylic copolymer had a high viscosity and was difficult to coat. . Thus, in the prior art, it was necessary to go through a dilution process to lower the viscosity by adding a solvent compatible with the acrylic copolymer to the pressure-sensitive adhesive composition. However, since the acrylic pressure-sensitive adhesive composition of the present invention has a low viscosity, there is no need to go through a separate dilution process, or since only a small amount of dilution solvent is used, processability and productivity are excellent. In addition, the acrylic pressure-sensitive adhesive composition according to the present invention has the advantage that, when the adhesive layer is formed, crosslinking is completed by itself, so that a special aging time for improving cohesion in the polymer is not required.

Polarizer

Next, the polarizing plate according to the present invention will be described.

The present invention is also a polarizing film; And a pressure-sensitive adhesive layer formed on one or both surfaces of the polarizing film and containing a cured product of the pressure-sensitive adhesive composition according to the present invention.

The type of polarizing film used in the present invention is not particularly limited, and general types known in this field can be adopted. For example, the polarizing film includes a polarizer; And it may include a protective film formed on one or both sides of the polarizer.

The type of the polarizer included in the polarizing plate of the present invention is not particularly limited, and for example, a general type known in this field, such as a polyvinyl alcohol-based polarizer, can be employed without limitation.

A polarizer is a functional film or sheet capable of extracting only light that vibrates in one direction from light incident while vibrating in various directions. Such a polarizer may be, for example, a form in which a dichroic dye is adsorbed and oriented in a polyvinyl alcohol-based resin film. The polyvinyl alcohol-based resin constituting the polarizer can be obtained, for example, by gelling a polyvinyl acetate-based resin. In this case, the polyvinyl acetate-based resin that can be used may include a copolymer of vinyl acetate and other monomers copolymerizable therewith, as well as a homopolymer of vinyl acetate. Examples of monomers copolymerizable with vinyl acetate include, but are not limited to, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having ammonium groups, or mixtures of two or more thereof. no. The gelation degree of the polyvinyl alcohol-based resin is usually about 85 mol% to about 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be further modified, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. In addition, the degree of polymerization of the polyvinyl alcohol-based resin may be usually about 1,000 to 10,000, preferably about 1,500 to 5,000. By forming the polyvinyl alcohol-based resin as described above, it can be used as a disc film of a polarizer. The method for forming a polyvinyl alcohol-based resin is not particularly limited, and a general method known in this field can be used.

The thickness of the disc film formed of a polyvinyl alcohol-based resin is not particularly limited, and may be appropriately controlled within a range of 1 μm to 150 μm, for example. In consideration of easiness of stretching and the like, the thickness of the disk film may be controlled to 10 μm or more.

The polarizer stretches (ex. uniaxially stretches) the polyvinyl alcohol-based resin film as described above, dyes the polyvinyl alcohol-based resin film with a dichroic dye, adsorbs the dichroic dye, and adsorbs the dichroic dye. The prepared polyvinyl alcohol-based resin film may be prepared through a process of treating with a boric acid aqueous solution and a process of washing with water after treating with a boric acid aqueous solution. As the dichroic dye, iodine or dichroic organic dye may be used.

The polarizing film of the present invention may further include a protective film formed on one or both surfaces of the polarizer. The type of the protective film that may be included in the polarizing plate of the present invention is not particularly limited, for example, a cellulose-based film such as triacetyl cellulose; Polyester-based films such as polycarbonate films or polyethylene terephthalate films; Polyethersulfone-based films; And/or a protective film composed of a polyethylene film, a polypropylene film, a polyolefin film having a cyclo-based or norbornene structure, or a polyolefin-based film such as an ethylene propylene copolymer. At this time, the thickness of the protective film is also not particularly limited, and may be formed in a conventional thickness.

On the other hand, in the present invention, the method of forming the adhesive layer on the polarizing film is not particularly limited, for example, a method of applying the pressure-sensitive adhesive composition (coating liquid) to the film or device using a conventional means such as a bar coater and heat-curing it. Alternatively, after applying the pressure-sensitive adhesive composition to the surface of the peelable substrate and heat-curing, a method of transferring the formed pressure-sensitive adhesive layer to the surface of the polarizing film or device may be used.

In the present invention, the process of forming the adhesive layer is also preferably performed after sufficiently removing air bubbles causing components such as volatile components or reaction residues in the adhesive composition (coating liquid). Accordingly, the crosslinking density or molecular weight of the pressure-sensitive adhesive is too low, so the elastic modulus is lowered, and bubbles present between the glass plate and the pressure-sensitive adhesive layer in a high temperature state can be prevented.

On the other hand, the adhesive layer formed as described above has a sol molecular weight of 300,000 g/mol to 600,000 g/mol, preferably 400,000 g/mol to 500,000 g/mol. The sol molecular weight is a value changed according to the polymerization conversion rate of the acrylic copolymer before curing, and when using an acrylic copolymer having a polymerization conversion ratio of 50% or less as in the present invention, it has a sol molecular weight in the above range.

On the other hand, the sol molecular weight is the molecular weight of the remaining residue after dissolving the adhesive layer in an organic solvent and then volatilizing the organic solvent through a drying process. Specifically, the sol molecular weight can be measured by the following method. First, the pressure-sensitive adhesive composition of the present invention is applied between two release films, and sufficiently heat-cured at 120° C. for 10 minutes to form an adhesive layer, and aged for 3 days under constant temperature and humidity conditions. Then, the release films were separated from the adhesive layer, and the adhesive layer was collected about 0.3 g to 0.5 g, placed in a 200 mesh wire mesh, placed in a container containing ethyl acetate, dissolved for 48 hours or more, and then dissolved at 80°C. Dry to volatilize the solvent. Then, the weight average molecular weight of the sample dried through GPC is measured, and this is taken as the sol molecular weight.

The polarizing plate of the present invention may further include at least one functional layer selected from the group consisting of a protective layer, a reflective layer, an anti-glare layer, a retardation plate, a wide viewing angle compensation film and a brightness enhancing film.

The polarizing plate according to the present invention as described above has little change over time in the adhesive layer, and is excellent in durability even under high temperature, high temperature/high humidity, and room temperature and low humidity conditions.

Specifically, the polarizing plate has a creep distance change rate defined by the following formula (1) of 10% or less, preferably 8% or less, and more preferably 5% or less.

Equation (1): Jungle distance change rate (%) = (T ₀ -T ₁ /T ₀ )×100

In the formula (1), T ₀ is a measurement distance by attaching the polarizing plate to a glass substrate to prepare a measuring specimen, and storing the measuring specimen at 23° C., 50% RH for 4 days, and then a pushing distance measured, T ₁ is the measurement distance after the specimen for measurement is stored at 23°C and 50%RH for 4 days, and further aged at 80°C for 1 day (aging).

In addition, the polarizing plate according to the present invention has an adhesive force change rate defined by the following formula (2) of 10% or less, preferably 5% or less, more preferably 4% or less.

Equation (2): Adhesion change rate (%) = (B ₀ -B ₁ /B ₀ )×100

In the formula (2), B ₀ is stored at 23° C. and 50% RH for 4 days, and then the measurement specimen prepared by attaching the polarizing plate to a glass substrate is 4 at 23° C. and 50% RH. After storage for a period of time, the adhesive force measured by pulling the polarizing plate under conditions of a peeling speed of 300 mm/min and a peeling angle of 180 degrees, and B ₁ was stored for 4 hours at 23° C. and 50% RH conditions for the measuring specimen. Next, after further aging at 80° C. for 1 day, the adhesive force is measured by pulling the polarizing plate under conditions of a peeling rate of 300 mm/min and a peeling angle of 180 degrees.

Display device

Next, the display device of the present invention will be described.

The display device of the present invention includes the polarizing plate according to the present invention described above.

More specifically, the display device may be a liquid crystal display device including a liquid crystal panel in which the polarizing plate according to the invention is bonded to one side or both sides. At this time, the type of the liquid crystal panel is not particularly limited. In the present invention, for example, but not limited to the type, TN (Twisted Neumatic) type, STN (Super Twisted Neumatic) type, F (ferroelectric) type and PD (polymer dispersed LCD) type, such as F various passive matrix system; Various active matrix methods including a two-terminal type and a three-terminal type; Any known liquid crystal panel including a transverse electric field (IPS mode) panel and a vertically oriented (VA mode) panel may be applied. In addition, the type of the other components included in the liquid crystal display device of the present invention and the manufacturing method thereof are not particularly limited, and general configurations in this field can be employed without limitation.

Next, the present invention will be described in more detail through specific examples.

Manufacturing example One

Nitrogen gas is refluxed, and in a 3L reactor equipped with a cooling device to facilitate temperature control, 84.9 parts by weight of butyl acrylate (BA) and hydroxybutyl acrylate (HBA) relative to 100 parts by weight of an alkyl (meth)acrylate-based monomer mixture ) 0.1 part by weight, a monomer mixture containing 15 parts by weight of allyl methacrylate (AMA) was added, and then 60 parts by weight of ethyl acetate (EAc) was added as a solvent, followed by purging nitrogen gas for 60 minutes for oxygen removal ( After purging), the temperature was maintained at 70°C.

Thereafter, 0.68 parts by weight of n-dodecyl mercaptan (n-DDM) as a molecular weight regulator and 0.02 parts by weight of polymerization initiator V-65 (Azobis (2-4-dimethylvaleronitrile), manufacturer Wako) were added and the polymerization conversion rate was 45. The reaction was carried out until it was% to prepare an acrylic copolymer (A-1). The molecular weight modifier was added in 5 portions during the reaction time.

Manufacturing example 2, 3 and Comparative manufacturing example 1 to 5

Acrylic copolymer (A-2) in the same manner as in Production Example 1, except that the type and content of the monomer used, the content of the polymerization initiator and the molecular weight modifier, and the polymerization conversion rate were changed as described in [Table 1] below. ), (A-3), and (B) to (F) were prepared.

The weight average molecular weight and the polymer structure of the acrylic copolymers prepared in Preparation Examples 1 to 3 and Comparative Preparation Examples 1 to 5 were measured as shown in Table 1 below.

(1) The weight average molecular weight was measured under the following conditions using GPC. For the calibration curve, measurement results were converted using standard polystyrene of the Agilent system.

<Measurement conditions>

Meter: Agilent GPC (Agulent 1200 series, USA)

Column: 2 PL Mixed B connections

Column temperature: 40℃

Eluent: Tetrohydrofuran

Flow rate: 1.0 mL/min

Concentration: ~ 1mg/mL (100μL injection)

(2) The polymer structure was evaluated by the following method.

First, the (meth)acrylic monomer having the same type of alkyl (meth)acrylate monomer and a crosslinkable functional group as used in the acrylic copolymer (hereinafter referred to as'copolymer to be evaluated') to evaluate the polymer structure Mixing to prepare a monomer mixture. At this time, the content of the (meth)acrylic monomer having a crosslinkable functional group in the monomer mixture was made to be the same as the content of the (meth)acrylic monomer having a crosslinkable functional group in the copolymer to be evaluated. Then, the monomer mixture was polymerized to prepare an acrylic copolymer (hereinafter referred to as a'reference copolymer') having a weight average molecular weight (error range ±5%) equivalent to that of the copolymer to be evaluated.

Thereafter, an ethyl acetate solvent was added to each of the reference copolymer and the copolymer to be evaluated to adjust the solid content concentration to 30%, and then the viscosity was measured. When the viscosity of the evaluation target copolymer measured as described above has a viscosity of 30% or more lower than that of the reference copolymer, it is evaluated as having a branched polymer structure, and in other cases, it is evaluated to have a linear polymer structure. .

On the other hand, the acrylic copolymer C prepared by Comparative Preparation Example 2 has a high viscosity, so it cannot pass through the column and the filter, and thus it is impossible to measure the weight average molecular weight and polymer structure.

[Table 1]

Example One

With respect to 100 parts by weight of the acrylic copolymer A-1 prepared by Preparation Example 1, 0.01 parts by weight of a polyfunctional curing agent (coronate L, manufactured by Nippon Polyurethane), silane coupling agent (beta-cyanoacetyl group-containing silane coupling agent ( LG Chem, M812) 0.2 parts by weight were blended and uniformly mixed to prepare a pressure-sensitive adhesive composition The ethyl acetate solvent was added to the pressure-sensitive adhesive composition so that the solid content was 30% by weight.

The prepared pressure-sensitive adhesive composition was applied to a polyethylene terephthalate film (release PET) having a thickness of 38 µm, which had been subjected to silicone peeling, and dried at a temperature of 120° C. for at least 10 minutes so that the thickness after drying became 23 µm, thereby forming an adhesive coating layer. . Thereafter, the adhesive coating layer was laminated to a conventional polarizing plate to prepare a polarizing plate comprising the adhesive layer.

Example 2 to 3

An adhesive composition and a polarizing plate were prepared in the same manner as in Example 1, except that the sample described in [Table 2] was used as the acrylic copolymer, and the solid content was adjusted as described in [Table 2].

Comparative example 1 to 6

Using the sample shown in [Table 3] as an acrylic copolymer, the content and solid content of the polyfunctional curing agent and the silane coupling agent were adjusted as described in [Table 3], and a crosslinking catalyst (DBTDL, Sigma-Aldrich) was used. A pressure-sensitive adhesive composition and a polarizing plate were prepared in the same manner as in Example 1, except that the composition was additionally blended with the contents shown in Table 3.

The physical properties of the pressure-sensitive adhesive composition and the polarizing plate prepared by Examples 1 to 3 and Comparative Examples 1 to 6 were measured by the following methods, and the measurement results are shown in Tables 2 and 3 below.

Method for measuring properties

(1) Coating viscosity (unit: cP)

The coating viscosity of the pressure-sensitive adhesive composition prepared by Examples and Comparative Examples was measured according to the following procedure using a Brookfield digital viscometer (RV DV2T).

220 mL of the pressure-sensitive adhesive composition was added to a 250 mL PE bottle, the lid was closed so that the solvent did not volatilize, and the film was sufficiently sealed with parafilm, etc., and then sufficiently left under constant temperature/humidity (23° C., 50% relative humidity) to remove air bubbles. Then, after removing the seal and the lid, a spindle was inserted at an angle to prevent bubbles from forming in the adhesive composition, the spindle was connected to a viscometer, and the liquid level of the adhesive composition was adjusted to fit the groove of the spindle. Then, the viscosity was measured under rpm conditions where torque was 20% (±1%).

(2) Coating properties

When the pressure-sensitive adhesive composition prepared by Examples and Comparative Examples was coated on a polyethylene terephthalate film, the state of the coating layer was visually observed and evaluated according to the following criteria.

<Coating property evaluation criteria>

○: Bubbles and streaks were not visually observed in the coating layer.

△: Bubbles and/or streaks were visually confirmed in the coating layer.

X: Cannot form a uniform coating layer

(3) Jungle distance (Creep, unit: μm)

The polarizer prepared in Examples and Comparative Examples was cut to a width of 10 mm and a length of 10 mm to prepare a specimen. Subsequently, the release PET film attached to the pressure-sensitive adhesive layer was peeled off, and the specimen was attached to an alkali free glass using a 2 kg roller according to the provisions of JIS Z 0237 to prepare a specimen for measurement. The specimen for measurement was stored for 4 days at constant temperature and humidity conditions (23°C, 50% RH), and then, using a TA equipment (Texture Analyzer, manufactured by Stable Micro Systems, UK), the distance T ₀ was measured. In this case, the creep distance (Creep) was measured as the distance (unit: μm) the polarizing plate was pushed from the glass substrate when the polarizing plate of the specimen for measurement was pulled for 1,000 seconds under a load of 1,000 g.

In addition, the specimen for measurement was stored for 4 days in constant temperature and humidity conditions (23°C, 50% RH), and then further aged for 1 day at 80°C, and then aged in the same manner to measure the pushing distance T ₁ . .

Then, the jungle distances T _O and T ₁ were substituted into the following equation (1) to calculate the jungle distance change rate.

Equation (1): Jungle distance change rate (%) = (T ₀ -T ₁ /T ₀ )×100

(4) Adhesion

After storing the polarizing plate prepared by Examples and Comparative Examples under constant temperature and humidity conditions (23°C, 50% R.H.) for 4 days, the polarizing plate was attached to a glass substrate to prepare a specimen for measurement.

Then, after storing the specimen for measurement for 4 hours under constant temperature and humidity conditions (23°C, 50% RH), the polarizing plate was completely separated from the glass substrate by pulling the polarizing plate under conditions of a peeling rate of 300 mm/min and a peel angle of 180 degrees. Adhesive force B ₀ (unit: gf/25mm) was measured by measuring the force required to measure.

In addition, after the specimen for measurement was stored at constant temperature and humidity conditions (23°C, 50% RH) for 4 hours, after further aging at 80°C for 1 day, adhesive force B ₁ was measured in the same manner.

Then, the adhesive strengths B ₀ and B ₁ were substituted into the following formula (2) to calculate the adhesive strength change rate.

Equation (2): Adhesion change rate (%) = (B ₀ -B ₁ /B ₀ )×100

(5) adhesion to substrate

After storing the polarizing plate prepared by Examples and Comparative Examples under constant temperature and humidity conditions (23° C., 50% RH) for 4 days, a paper tape having an adhesive layer (American Tape (Made IN USA)) was placed on the adhesive layer of the polarizing plate. It was attached to a test specimen for measurement, and after 1 hour or more, the paper tape was peeled off, and the initial substrate adhesion was measured according to the following evaluation criteria.

In addition, after the specimen for measurement was stored under constant temperature and humidity conditions (23°C, 50% R.H.) for 4 hours, further aged at 80°C for 1 day (aging), and then aged in the same manner, the substrate adhesion was measured.

<Evaluation criteria>

OK: Polarizing plate adhesive layer is not transferred on paper tape

NG: Polarizing plate adhesive layer is transferred on paper tape

(6) Durability evaluation

The polarizing plate prepared by Examples and Comparative Examples was cut to a size of 180 mm×250 mm (length×width) to prepare a sample, and the sample was attached to a 19-inch commercial panel using a laminator. Then, the panel was compressed for about 20 minutes in an autoclave (50°C and 5 atmospheres), and then stored in a constant temperature and humidity condition (23°C, 50% R.H.) for 24 hours to prepare a specimen.

The heat resistance and durability were evaluated by observing whether or not air bubbles or peeling occurred after the prepared specimens were left at a temperature of 80° C. for 500 hours.

Moisture resistance and heat resistance were evaluated by observing whether or not bubbles or peeling occurred at the interface of the adhesive layer after the prepared specimens were left at a temperature of 60° C. and a relative humidity of 90% R.H. for 500 hours.

The room temperature and low humidity heat resistance was evaluated by observing whether or not bubbles or peeling occurred at the interface of the adhesive layer after leaving the prepared specimen under a temperature of 25° C. and a relative humidity of 25% R.H. for 250 hours.

<Evaluation criteria>

○: No bubbles or peeling occurred

△: Some bubbles and/or peeling occurred

×: large amount of air bubbles and/or peeling occurred

[Table 2]

[Table 3]

As shown in [Table 2], the pressure-sensitive adhesive composition prepared by Examples 1 to 3 exhibited low viscosity even when the solid content was 30% by weight, and the coating property was excellent. There was little change over time with physical properties, and heat resistance, moisture heat resistance and low temperature and low humidity were all excellent.

On the other hand, in the case of the pressure-sensitive adhesive composition of Comparative Example 1 using the acrylic copolymer B containing less than 10 parts by weight of the monomer represented by [Formula 1], the coating viscosity properties were excellent, but the adhesive layer physical properties after formation of the pressure-sensitive adhesive layer It was found that the change was large and the durability at room temperature and low humidity was reduced.

On the other hand, the pressure-sensitive adhesive composition of Comparative Example 2 using an acrylic copolymer C having a monomer content of more than 20 parts by weight represented by [Formula 1] and a weight average molecular weight is high, a comparative example using an acrylic copolymer D having a polymerization conversion rate of 80% The pressure-sensitive adhesive composition of 3 was too high in viscosity to form an adhesive layer, and as a result, the physical properties of the pressure-sensitive adhesive layer could not be measured.

On the other hand, as in Comparative Example 4, when the solid content of the acrylic copolymer D was lowered to a level of 12% by weight, it was possible to form an adhesive layer, but a change in physical properties over time of the formed adhesive layer was very high.

On the other hand, in Comparative Example 5 using a linear acrylic copolymer E having a low weight average molecular weight and Comparative Example 6 using an acrylic copolymer F using oleyl acrylate instead of the monomer represented by Formula 1], the coating viscosity properties were good. , It has been found that the adhesive layer has poor characteristics over time and the durability at low temperatures and low humidity.

Claims (14)

It is an acrylic pressure-sensitive adhesive composition comprising an acrylic copolymer formed by polymerizing a monomer mixture comprising a monomer represented by the following [Formula 1], an alkyl (meth)acrylate monomer and a (meth)acrylic monomer having a crosslinkable functional group,
The monomer mixture includes 10 to 20 parts by weight based on 100 parts by weight of the monomer mixture represented by [Formula 1],
The acrylic adhesive composition having a polymerization conversion rate of 50% or less of the acrylic copolymer.
[Formula 1]

In Chemical Formula 1,
R1 and R2 are each independently hydrogen or a C1 to C4 alkyl group,
A is a single bond, a C1 to C4 alkylene group, ether, ester, or a combination thereof.
According to claim 1,
The acrylic copolymer is an acrylic pressure-sensitive adhesive composition having a weight average molecular weight of 300,000 to 500,000g/mol.
According to claim 1,
The monomer represented by [Formula 1] is allyl methacrylate, allyl acrylate, methalyl methacrylate, methalyl acrylate, 3-butenyl Acrylate (3-butenyl acrylate), butt-3-enyl-2-methylprop-2-enoate, 2-allyloxyethyl acrylate (2 -allyloxyethyl acrylate, 2-allyloxyethyl methacrylate, 3-allyloxypropyl methacrylate, 3-allyloxypropyl acrylate, 2 -Acrylic adhesive composition of at least one selected from the group consisting of 2-allyloxyethoxyethyl methacrylate and 2-allyloxyethoxyethyl acrylate.
According to claim 1,
The monomer mixture, the acrylic pressure-sensitive adhesive composition comprising the (meth) acrylic monomer having the crosslinkable functional group in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the monomer mixture.
According to claim 1,
The monomer mixture, based on 100 parts by weight of the monomer mixture,
79 parts by weight to 89.99 parts by weight of the alkyl (meth)acrylate-based monomer;
0.01 to 1 part by weight of a (meth)acrylic monomer having a crosslinkable functional group; And
Acrylic pressure-sensitive adhesive composition comprising 10 to 20 parts by weight of the monomer represented by [Formula 1].
According to claim 1,
The pressure-sensitive adhesive composition is an acrylic pressure-sensitive adhesive composition that further comprises a multifunctional curing agent.
The method of claim 6,
The polyfunctional curing agent is one or more acrylic pressure-sensitive adhesive composition selected from the group consisting of isocyanate-based compounds, epoxy-based compounds, aziridine-based compounds, and metal chelate-based compounds.
The method of claim 6,
The multifunctional curing agent is an acrylic pressure-sensitive adhesive composition that is contained in 0.001 to 0.1 parts by weight based on 100 parts by weight of the acrylic copolymer.
According to claim 1,
The adhesive composition has a solid content of 30% by weight or more,
Acrylic pressure-sensitive adhesive composition having a viscosity of 500cP to 3000cP at 23°C.
Polarizing film; And a pressure-sensitive adhesive layer formed on one or both sides of the polarizing film, and comprising a cured product of the acrylic pressure-sensitive adhesive composition of any one of claims 1 to 9.
The method of claim 10,
The polarizing plate is a polarizing plate having a creep distance (Creep) change rate of 10% or less defined by the following formula (1).
Equation (1): Jungle distance change rate (%) = (T ₀ -T ₁ /T ₀ )×100
In the formula (1), T ₀ is a measurement distance by attaching the polarizing plate to a glass substrate to prepare a measuring specimen, and storing the measuring specimen at 23° C., 50% RH for 4 days, and then a pushing distance measured, T ₁ is the measurement distance after the specimen for measurement is stored at 23°C and 50%RH for 4 days, and further aged at 80°C for 1 day (aging).
The method of claim 10,
The polarizing plate is a polarizing plate having an adhesive force change rate of 10% or less defined by the following formula (2).
Equation (2): Adhesion change rate (%) = (B ₀ -B ₁ /B ₀ )×100
In the formula (2),
B ₀ is stored for 4 days at 23°C and 50%RH conditions for the polarizing plate, and then the measurement specimen prepared by attaching the polarizing plate to a glass substrate is stored at 23°C and 50%RH conditions for 4 hours, and then peeled. The adhesive force measured by pulling the polarizing plate under the conditions of a speed of 300 mm/min and a peeling angle of 180 degrees,
B ₁ is stored at 23° C., 50% RH for 4 hours, and then aged at 80° C. for 1 day, and the peeling rate is 300 mm/min and the peeling angle is 180°. Adhesive force measured by pulling the polarizer.
The method of claim 10,
The adhesive layer is a polarizing plate having a sol molecular weight of 300,000 to 600,000 g/mol.
A display device comprising the polarizing plate of claim 10.