KR102488350B1 - Acryl-based adhesive composition, polarizing plate and display device - Google Patents

Abstract

상기 화학식 1에서, R1 및 R2는 각각 독립적으로 수소, 또는 C1~C4 알킬기이고, A는 단일결합, C1~C4 의 알킬렌기, 에테르, 에스테르, 또는 이들의 조합이다. The present invention is an acrylic copolymer 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. A pressure-sensitive adhesive composition, wherein the monomer mixture contains 10 to 20 parts by weight of the monomer represented by Formula 1 with respect to 100 parts by weight of the monomer mixture, and the polymerization conversion rate of the acrylic copolymer is 50% or less Acrylic pressure-sensitive adhesive composition, It relates to a polarizing plate and a display device manufactured using the same.
[Formula 1]

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

Description

Acrylic pressure-sensitive adhesive composition, polarizing plate and display device {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 particularly, an acrylic pressure-sensitive adhesive composition having excellent durability, particularly durability under room temperature and low humidity conditions, and little change with time after forming an adhesive layer, and a polarizing plate manufactured using the same and a display device.

In general, a liquid crystal display device (LCD) includes a liquid crystal cell containing liquid crystal and a polarizing plate, and an adhesive layer is used to attach the liquid crystal cell and the polarizing plate. Acrylic resins, rubbers, urethane resins, silicone resins, or EVA (Ethylene Vinyl Acetate) are used as adhesives for attaching polarizers forming such an adhesive layer, and among them, acrylic resins having transparency, oxidation resistance, and yellowing resistance are used as a base. Many adhesives are used.

In the case of an acrylic pressure-sensitive 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, the curing efficiency is lowered and the curing rate is slowed, and the cohesive force and curing degree of the pressure-sensitive adhesive are lowered under high temperature or high temperature/high humidity conditions, thereby lowering durability. However, when an acrylic resin having a high weight average molecular weight is used, the viscosity of the coating solution increases and workability deteriorates. The viscosity of the coating solution can be adjusted by lowering the solids content in the coating solution, but when the adhesive layer is formed using a coating solution with such a low solid content, manufacturing 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 exhibiting relatively low viscosity characteristics is used, but an acrylic resin is prepared by adding a monomer having a crosslinkable functional group such as a hydroxyl group or a carboxyl group, and the acrylic resin is prepared. A method of improving durability of an adhesive layer has been proposed by mixing a curing agent with a resin and forming a cross-linked structure between polymer chains through a reaction between the curing agent and a cross-linkable functional group during coating. However, in the case of such a conventional method, the crosslinking reaction proceeds slowly due to the curing agent remaining after the formation of the adhesive layer is completed, and the peeling force of the adhesive layer decreases over time due to this additional crosslinking reaction. As a result, problems such as deterioration in durability of the polarizing plate occur.

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

In addition, the present invention is to provide a polarizing plate including 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. An acrylic pressure-sensitive adhesive composition comprising, wherein the monomer mixture contains 10 to 20 parts by weight of the monomer represented by Formula 1 based on 100 parts by weight of the monomer mixture, and 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-C4 alkyl group, and A is a single bond, a C1-C4 alkylene group, an ether, an ester, or a combination thereof.

In another aspect, the present invention provides a polarizing film; and an adhesive layer formed on one side or both sides of the polarizing film and including a cured product of the acrylic 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 Formula 1, and has a low solid content even when the solid content in the coating solution is as high as 30% by weight or more. Since the viscosity can be realized, the coating workability is excellent and the productivity is high when forming the adhesive layer, and the thickness of the adhesive layer can be precisely controlled.

In addition, the acrylic pressure-sensitive adhesive composition according to the present invention uses an acrylic copolymer having a low polymerization conversion rate and uses an unsaturated hydrocarbon functional group remaining in the copolymer so that an additional crosslinking reaction can proceed when forming the adhesive layer, so that the amount of curing agent used compared to the prior art can be significantly reduced, and accordingly, the generation of change over time in the adhesive layer due to the unreacted curing agent can be effectively suppressed.

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

Hereinafter, the present invention will be specifically described.

When 'includes', 'has', 'consists of', etc. mentioned in this specification is used, other parts may be added unless 'only' is used. In the case where a component is expressed in the singular, the case including the plural is included unless otherwise explicitly stated.

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

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

In this specification, “X to Y” representing 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 air formed by polymerizing a monomer mixture including a monomer represented by the following [Formula 1], an alkyl (meth)acrylate monomer, and a (meth)acrylic monomer having a crosslinkable functional group. contains a composite

[Formula 1]

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

The A may be a single bond, a C1~C4 alkylene group, an ether, an ester, or a combination thereof, and preferably, a C1~C4 alkylene group or a C1~C4 oxyalkylene group. If the length of the carbon chain of A is too long, it is difficult to realize the desired level of weight average molecular weight during polymerization of the acrylic copolymer, and the crosslinking reaction may not be smoothly performed during coating of the adhesive layer, which may deteriorate the physical properties of the adhesive layer. there is.

The monomer represented by [Formula 1] is used to form a cross-linked structure and form a branched polymer in the adhesive layer formation process, for example, allyl methacrylate, allyl acrylate ), methallyl methacrylate, methallyl 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 ), but may be one or more selected from the group consisting of, but is not limited thereto.

Conventionally, as acrylic copolymers used in adhesives for polarizing plates, acrylic copolymers having a linear polymer structure in which monomers are polymerized in the form of one long chain have been mainly used. However, in the case of using such acrylic copolymers having a linear structure, as the weight average molecular weight increases, the viscosity also increases, resulting in poor workability.

However, since the monomer of [Chemical Formula 1] has two or more ethylene groups, each radical can be formed in free radical polymerization, and as a result, the chains can grow in different directions, so two or more chains with different growth directions A branched polymer having is 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, excellent coating properties can be realized 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 during the polymerization process and remain in the copolymer, and then react with heat during the adhesive layer formation process (coating process) to form a crosslinked structure. will form Therefore, when the monomer represented by [Formula 1] is included as described above, there is no need to include an excessive amount of a curing agent for forming an internal cross-linked structure of the pressure-sensitive adhesive composition.

The monomer represented by [Formula 1] may be included in 10 to 20 parts by weight, preferably 12 to 18 parts by weight, based on 100 parts by weight of the monomer mixture. 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 under room temperature and low humidity conditions, and if 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 includes an alkyl group having 2 to 14 carbon atoms. This is because if the alkyl group included in the alkyl (meth)acrylate-based monomer is excessively long, the cohesive force of the pressure-sensitive adhesive may decrease, and it may be difficult to control the glass transition temperature (Tg) or adhesiveness. For example, examples of the alkyl (meth) acrylate 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 ) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate and tetradecyl (meth) acrylate, and in the present invention, one or a mixture of two or more of the above 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 adhesive strength and durability can be obtained.

Next, the (meth)acrylic monomer having the crosslinkable functional group is for improving adhesion between the pressure-sensitive adhesive and the substrate. In the past, it was common to use a (meth)acrylic monomer having a crosslinkable functional group to improve cohesion for elasticity of the pressure-sensitive adhesive, but the acrylic copolymer of the present invention can exhibit sufficient cohesive strength 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 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 carboxy group-containing monomer, or a nitrogen-containing monomer may be used, but is not limited thereto. Specific examples of the above hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, ) acrylate, 8-hydroxyoctyl (meth) acrylate, 2-hydroxyethylene glycol (meth) acrylate or 2-hydroxypropylene glycol (meth) acrylate, and the like, examples of the carboxyl group-containing monomer is (meth)acrylic acid, 2-(meth)acryloyloxy acetic acid, 3-(meth)acryloyloxy propyl acid, 4-(meth)acryloyloxy butyric acid, acrylic acid doublet, itaconic acid, maleic acid and maleic anhydride. 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 has 79 parts by weight to 89.99 parts by weight of an alkyl (meth)acrylate-based monomer and 0.01 to 1 part by weight of a crosslinkable functional group, based on 100 parts by weight of the monomer mixture ( It may be formed by polymerizing a monomer mixture including a meth)acrylic monomer and 10 to 20 parts by weight of the monomer represented by [Chemical Formula 1].

The acrylic copolymer according to the present invention may be prepared by mixing each of the above-described monomers to prepare a monomer mixture and then polymerizing the monomer mixture. At this time, the polymerization reaction is terminated when the polymerization conversion rate reaches a level of 50% or less, preferably 30 to 50%, more preferably 40 to 50%. Since the present invention includes a high content of 10 to 20 parts by weight of the monomer represented by [Formula 1], when the polymerization conversion rate exceeds 50%, the viscosity increases and coating properties may deteriorate. 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 cross-linking structure is not sufficiently formed during formation of the adhesive layer, and thus durability may decrease. When the weight average molecular weight exceeds 500,000 g/mol, gelation occurs. As a result, the coating properties may be deteriorated.

Meanwhile, the polymerization method is not particularly limited, and various polymerization methods known in the art, such as solution polymerization, photopolymerization, 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 input timing of each component is not particularly limited. That is, the components may be added at once or divided into several times.

In the present invention, the acrylic copolymer can be prepared using a solution polymerization method, and the solution polymerization is carried out at a polymerization temperature of 50 ° C to 140 ° C by adding a polymerization initiator in a state in which each monomer is uniformly mixed. 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 one or a mixture of two 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, terpenes of dipentene or t-terpene, chloroform, halogenated hydrocarbons of carbon tetrachloride, or pentaerythritol Tetrakis (3-mercapto propionate), etc. may be used, but is not limited thereto.

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

(2) polyfunctionality curing agent

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 interfacial adhesion with a substrate, and the type is not particularly limited, and various curing agents used in the art, for example, isocyanate-based compounds, epoxy-based compounds, aziridine-based compounds, and At least one selected from the group consisting of metal chelate compounds may be used.

As the isocyanate-based compound, conventional ones known in the art may be used, and examples thereof include toluene diisocyanate, 2,4-trylene diisocyanate, 2,6-trylene diisocyanate, hydrogenated tolylene 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, torylene diisocyanate adduct of trimethylolpropane, xylene diisocyanate adduct of trimethylolpropane, triphenylmethane triisocyanate, methylene bis triisocyanate, polyols thereof (trimethylolpropane) or mixtures thereof, etc. can be used

Examples of the epoxy-based 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-aziridine). dincarboxamide), triethylene melamine, bisisoprotaloyl-1-(2-methylaziridine), tri-1-aziridinylphosphine oxide, or mixtures thereof.

Examples of the metal chelate compound include compounds in which a multivalent metal such as aluminum, iron, zinc, tin, titanium, antimony, magnesium, and/or vanadium is coordinated with acetyl acetone or ethyl acetoacetate. , but is not limited thereto.

The multifunctional curing agent is preferably included in an amount of 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, since the unsaturated hydrocarbon group remaining inside the acrylic copolymer reacts to form a cross-linked structure when the adhesive layer is formed, it is not necessary to include an excessive amount of a curing agent to form a cross-linked structure, and It contains only a small amount of curing agent for the purpose of improving interfacial adhesion. When the content of the multifunctional curing agent is less than 0.001 parts by weight, the effect of improving adhesion to the substrate is insignificant, and when it exceeds 0.1 parts by weight, the physical properties of the adhesive may change over time. 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 in physical properties of the pressure-sensitive adhesive layer due to the remaining 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 tackifier resin, an additive, and other components in addition to the above-described components for physical property adjustment.

The pressure-sensitive adhesive composition of the present invention may further include a solvent for viscosity control. The solvent may be a polymerization solvent used in the process of preparing the acrylic copolymer, and may also be a dilution solvent added to adjust the viscosity, if 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, 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-acetoacetate propyl trimethoxy silane, γ-acetoacetate propyl triethoxy silane, β-cyanoacetyl trimethoxy silane, β-cyanoacetyl triethoxy silane, and acetoxy aceto trimethoxy silane, and one or a mixture of two or more of the above may be used. In the present invention, it is preferable to use a silane-based coupling agent having an acetoacetate group or a β-cyanoacetyl group, but is not limited thereto. In the composition of the present invention, the silane-based coupling agent may be included in an amount of 0.01 part by weight to 5 parts by weight, preferably 0.01 part by weight 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 parts by weight, the effect of increasing the adhesive force is insignificant, and if it exceeds 5 parts by weight, there is a risk that durability may decrease.

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 based on 100 parts by weight of the acrylic copolymer, from the viewpoint of adjusting the adhesive performance. The type of such tackifying resin is not particularly limited, and examples thereof include (hydrogenated) hydrocarbon-based resins, (hydrogenated) rosin resins, (hydrogenated) rosin ester resins, (hydrogenated) terpene resins, (hydrogenated) terpene phenol resins, One type or a mixture of two or more types of polymerized rosin resin or polymerized rosin ester resin may be used. If the content of the tackifying resin is less than 1 part by weight, there is a fear that the addition effect will be insignificant, and if it exceeds 100 parts by weight, there is a fear that the compatibility and/or cohesive strength improving effect will be reduced.

The pressure-sensitive adhesive composition of the present invention also includes at least one additive selected from the group consisting of an epoxy resin, a curing agent, a UV stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, an antifoaming agent, a surfactant, and a plasticizer, to the extent that the effect of the present invention is not affected. may additionally include.

The acrylic pressure-sensitive adhesive composition according to the present invention uses an acrylic copolymer with a low polymerization conversion rate and uses an unsaturated hydrocarbon functional group remaining in the copolymer so that an additional crosslinking reaction can proceed when forming the adhesive layer, so that the amount of curing agent is significantly reduced compared to the prior art. Therefore, it is possible to effectively suppress the generation 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 uses an acrylic copolymer having a low polymerization conversion rate and a branched polymer structure, compared to the pressure-sensitive adhesive composition using an acrylic copolymer of a linear polymer structure having the same level of weight average molecular weight. Low viscosity can be realized. Specifically, the pressure-sensitive adhesive composition according to the present invention has a viscosity of 3,000 cP or less at 23 ° C., preferably 500 cP to 3,000 cP, when the solid content is 30 wt% or more, for example, 30 wt% to 60 wt%. More preferably, it appears as low as 500 cP to 2,000 cP. In this case, the solid content may mean 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 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, the solid content in the coating solution can be increased without deterioration in coating properties, so that productivity is excellent and precise control of thickness and the like is possible.

On the other hand, in the case of the conventional acrylic pressure-sensitive adhesive composition, an acrylic copolymer having a high weight average molecular weight was used to realize physical properties such as durability, and the pressure-sensitive adhesive composition containing such an acrylic copolymer had difficulty in coating due to its high viscosity. . Accordingly, in the prior art, it was necessary to undergo a dilution process for lowering 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 low viscosity, it does not require a separate dilution process or uses only a small amount of dilution solvent, so processability and productivity are excellent. In addition, the acrylic pressure-sensitive adhesive composition according to the present invention has the advantage that crosslinking is completed by itself when the formation of the pressure-sensitive adhesive layer is completed, so that no special aging time is required to improve the cohesiveness inside the polymer.

polarizer

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

The present invention also provides a polarizing film; and a pressure-sensitive adhesive layer formed on one side or both sides 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 employed. For example, the polarizing film may include a polarizer; And it may include a protective film formed on one side or both sides of the polarizer.

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

A polarizer is a functional film or sheet capable of extracting only light vibrating in one direction from incident light vibrating in several directions. Such a polarizer may be, for example, a form in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film. The polyvinyl alcohol-based resin constituting the polarizer can be obtained by gelating a polyvinyl acetate-based resin, for example. In this case, the polyvinyl acetate-based resin that can be used may include a homopolymer of vinyl acetate as well as a copolymer of vinyl acetate and other monomers copolymerizable therewith. Examples of the monomer copolymerizable with vinyl acetate include one or a mixture of two or more of unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group. not. The gelation degree of the polyvinyl alcohol-based resin may be usually about 85 mol% to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be further modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may also be used. In addition, the degree of polymerization of the polyvinyl alcohol-based resin may be usually about 1,000 to about 10,000, preferably about 1,500 to 5,000. The above polyvinyl alcohol-type resin can be formed into a film and used as a raw film of a polarizer. A method for forming a polyvinyl alcohol-based resin into a film is not particularly limited, and a general method known in this field can be used.

The thickness of the original film formed of the polyvinyl alcohol-based resin is not particularly limited, and may be appropriately controlled within the range of 1 μm to 150 μm, for example. Considering the ease of stretching, etc., the thickness of the raw film may be controlled to 10 μm or more.

The polarizer is a step of stretching (ex. uniaxial stretching) the polyvinyl alcohol-based resin film as described above, a step of dyeing the polyvinyl alcohol-based resin film with a dichroic dye, and adsorbing the dichroic dye, and adsorbing the dichroic dye. It can be manufactured through a process of treating the polyvinyl alcohol-based resin film with an aqueous solution of boric acid and a process of washing with water after treatment with an aqueous solution of boric acid. As the dichroic dye, iodine or a dichroic organic dye may be used.

The polarizing film of the present invention may further include a protective film formed on one side or both sides of the polarizer. The type of protective film that can be included in the polarizing plate of the present invention is not particularly limited, and examples include cellulose-based films such as triacetyl cellulose; polyester-based films such as polycarbonate films or polyethylene terephthalate films; polyethersulfone-based film; 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, etc. may be formed as a laminated multi-layer film. At this time, the thickness of the protective film is also not particularly limited, and may be formed to 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 an adhesive composition (coating liquid) to the film or device by a common means such as a bar coater and heat-curing; Alternatively, a method in which the pressure-sensitive adhesive composition is once applied to the surface of the peelable substrate and cured by heat, and then the formed pressure-sensitive adhesive layer is transferred to the surface of the polarizing film or device.

In the present invention, the formation of the pressure-sensitive adhesive layer is preferably performed after sufficiently removing components causing bubbles such as volatile components or reaction residues in the pressure-sensitive adhesive composition (coating solution). Accordingly, the crosslinking density or molecular weight of the pressure-sensitive adhesive is too low, and the elastic modulus is lowered, and air bubbles existing between the glass plate and the pressure-sensitive adhesive layer become larger in a high temperature state, thereby preventing the formation of internal scattering bodies.

Meanwhile, 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 that changes according to the polymerization conversion rate of the acrylic copolymer before curing, and when an acrylic copolymer having a polymerization conversion rate of 50% or less is used as in the present invention, the sol molecular weight is within the above range.

Meanwhile, the molecular weight of the sol is the molecular weight of a residue remaining 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, 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 about 0.3 g to 0.5 g of the adhesive layer was collected, put in a 200 mesh wire mesh, put in a container containing ethyl acetate, left for 48 hours or more to dissolve, and then heated to 80 ° C. Dry to volatilize the solvent. Thereafter, the weight average molecular weight of the dried sample is measured through GPC, and this is referred to 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 luminance enhancing film.

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

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

Equation (1): Change rate of slip distance (%) = (T ₀ -T ₁ /T ₀ )×100

In Equation (1), T ₀ is a sliding distance measured after attaching the polarizing plate to a glass substrate to prepare a specimen for measurement, and storing the specimen for measurement at 23 ° C. and 50% RH for 4 days, and T ₁ is the sliding distance measured after storing the specimen for measurement at 23 ° C and 50% RH for 4 days and additionally aging at 80 ° C for 1 day.

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, and more preferably 4% or less.

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

In Equation (2), B ₀ is the measurement specimen prepared by attaching the polarizer to a glass substrate after storing the polarizing plate at 23 ° C. and 50% RH condition for 4 days. After storage for an hour, the adhesive strength measured by pulling the polarizer under the conditions of a peeling speed of 300 mm/min and a peeling angle of 180 degrees, B ₁ is the specimen stored for 4 hours at 23 ° C. and 50% RH. Next, after further aging at 80 ° C. for 1 day, the adhesive strength was measured by pulling the polarizing plate under the conditions of a peeling speed 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 a polarizing plate according to the present invention is bonded to one or both surfaces. At this time, the type of the liquid crystal panel is not particularly limited. In the present invention, for example, without being limited to the type, F various passive matrices including TN (Twisted Neumatic) type, STN (Super Twisted Neumatic) type, F (ferroelectric) type and PD (polymer dispersed LCD) type, etc. method; various active matrix methods including two terminal and three terminal; All known liquid crystal panels including an IPS mode panel and a VA mode panel may be applied. In addition, the types and manufacturing methods of other components included in the liquid crystal display device of the present invention are not particularly limited, and general configurations in this field can be adopted and used without limitation.

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

manufacturing example One

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

Then, 0.68 parts by weight of n-dodecylmercaptan (n-DDM) as a molecular weight regulator and 0.02 parts by weight of V-65 (Azobis(2-4-dimethylvaleronitrile), manufactured by Wako) as a polymerization initiator were added, and the polymerization conversion rate was 45 The reaction was progressed until the % was obtained to prepare an acrylic copolymer (A-1). The molecular weight modifier was added in 5 divided steps during the reaction time.

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

Acrylic copolymer (A-2 ), (A-3), and (B) to (F) were prepared.

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

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

<Measurement conditions>

Meter: Agilent GPC (Agulent 1200 series, USA)

Column: Connect 2 PL Mixed B

Column temperature: 40°C

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 same type of alkyl (meth) acrylate monomer and a (meth) acrylic monomer having a crosslinkable functional group as those used in the acrylic copolymer (hereinafter referred to as 'evaluation subject copolymer') whose polymer structure is to be evaluated A monomer mixture was prepared by mixing. At this time, the content of the (meth)acrylic monomer having a crosslinkable functional group in the monomer mixture was made equal to 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 'standard copolymer') having a weight average molecular weight (error range ±5%) equivalent to that of the copolymer to be evaluated.

Thereafter, 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 copolymer to be evaluated measured as described above was 30% or more lower than that of the reference copolymer, it was evaluated as having a branched polymer structure, and in other cases, it was evaluated as having a linear polymer structure. .

On the other hand, the acrylic copolymer C prepared in Comparative Preparation Example 2 had a high viscosity and could not pass through the column and filter, making it impossible to measure the weight average molecular weight and polymer structure.

[Table 1]

Example One

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

The prepared adhesive composition was applied to a polyethylene terephthalate film (release PET) having a thickness of 38 μm treated with silicone peeling and dried at a temperature of 120 ° C. for 10 minutes or more so that the thickness after drying was 23 μm to form an adhesive coating layer. . Thereafter, the adhesive coating layer was laminated on a conventional polarizing plate to prepare a polarizing plate including the adhesive layer.

Example 2 to 3

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

comparative example 1 to 6

Samples described in [Table 3] below were used as acrylic copolymers, and the content and solid content of a multifunctional curing agent and a silane coupling agent were adjusted as described in [Table 3], and a crosslinking catalyst (DBTDL, Sigma-Aldrich) A pressure-sensitive adhesive composition and a polarizing plate were prepared in the same manner as in Example 1, except that they were additionally formulated in the contents described in [Table 3].

Physical properties of the pressure-sensitive adhesive composition and the polarizing plate prepared in 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.

Physical property measurement method

(1) Coating Viscosity (unit: cP)

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

About 220 mL of the adhesive composition was put in a 250 mL PE bottle, the lid was closed to prevent the solvent from evaporating, and air bubbles were removed by sufficiently sealing it with parafilm or the like, and then sufficiently leaving it at constant temperature / constant humidity (23 ° C, 50% relative humidity) conditions. Then, after removing the seal and lid, a spindle was inserted at an angle so as not to generate bubbles in the pressure-sensitive adhesive composition, the spindle was connected to a viscometer, and the liquid level of the pressure-sensitive adhesive composition was adjusted to fit the groove of the spindle. Then, the viscosity was measured under the rpm condition that the torque was 20% (±1%).

(2) coating property

When the pressure-sensitive adhesive composition prepared in 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.

<Criteria for evaluation of coating properties>

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

Δ: Bubbles and/or streaks were observed visually in the coating layer.

X: Impossible to form a uniform coating layer

(3) creep distance (Creep, unit: ㎛)

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

In addition, the specimen for measurement was stored for 4 days under constant temperature and humidity conditions (23 ° C, 50% RH), and then additionally aged at 80 ° C. for 1 day, and then aged in the same way. The sliding distance T ₁ was measured .

Then, the sliding distance change rate was calculated by substituting the rolling distance T _O and T ₁ into the following equation (1).

Equation (1): Change rate of slip distance (%) = (T ₀ -T ₁ /T ₀ )×100

(4) Adhesion

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

Then, the specimen for measurement was stored for 4 hours under constant temperature and humidity conditions (23 ° C, 50% RH), and then the polarizing plate was completely separated from the glass substrate by pulling the polarizing plate under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 degrees The adhesive strength B ₀ (unit: gf/25mm) was measured by measuring the force required to do so.

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

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

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

(5) Substrate adhesion

After storing the polarizers prepared in Examples and Comparative Examples for 4 days under constant temperature and humidity conditions (23° C., 50% R.H.), a paper tape (American Tape (Made IN USA) having an adhesive layer was applied on the adhesive layer of the polarizer. to prepare a specimen for measurement, and then, after 1 hour or more, the paper tape was removed, and adhesion to the initial substrate was measured according to the following evaluation criteria.

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

<Evaluation Criteria>

OK: The polarizer adhesive layer is not transferred onto the paper tape.

NG: The polarizer adhesive layer is transferred onto the paper tape

(6) Durability evaluation

A sample was prepared by cutting the polarizer prepared in Examples and Comparative Examples to a size of 180 mm × 250 mm (length × width), and the sample was attached to a 19-inch commercially available panel using a laminator. Thereafter, the panel was pressed for about 20 minutes in an autoclave (50° C. and 5 atm), and then stored for 24 hours under constant temperature and humidity conditions (23° C., 50% R.H.) to prepare specimens.

Heat resistance durability was evaluated by leaving the prepared specimen at a temperature of 80 ° C. for 500 hours, and then observing whether bubbles or peeling occurred.

Moist heat resistance durability was evaluated by observing the occurrence of air bubbles or peeling at the interface of the adhesive layer after the prepared specimen was left for 500 hours under conditions of a temperature of 60° C. and a relative humidity of 90% R.H.

Room temperature and low humidity heat resistance was evaluated by observing the occurrence of bubbles or peeling at the interface of the adhesive layer after the prepared specimen was left for 250 hours under conditions of a temperature of 25° C. and a relative humidity of 25% R.H.

<Evaluation Criteria>

○: no bubbles and peeling

△: Bubbles and/or slight peeling

×: A large amount of bubbles and/or peeling occurs

[Table 2]

[Table 3]

As shown in [Table 2], the pressure-sensitive adhesive compositions prepared in Examples 1 to 3 showed low viscosity characteristics even when the solid content was 30% by weight and had excellent coating properties, and the pressure-sensitive adhesive layer prepared using the same The change in physical properties over time was small, and heat resistance, heat and humidity resistance, and room temperature and low humidity were all excellent.

In contrast, in the case of the adhesive composition of Comparative Example 1 using the acrylic copolymer B containing less than 10 parts by weight of the monomer represented by [Chemical Formula 1], the coating viscosity characteristics were excellent, but the physical properties of the adhesive layer were deteriorated over time after formation of the adhesive layer. It was found that the change was large and the durability at room temperature and low humidity was lowered.

On the other hand, the adhesive composition of Comparative Example 2 using acrylic copolymer C having a monomer content of more than 20 parts by weight represented by [Formula 1] and a comparative example using acrylic copolymer D having a high weight average molecular weight and a polymerization conversion rate of 80% The adhesive composition of 3 had too high a viscosity to form an adhesive layer, and thus the physical properties of the 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 12% by weight, it was possible to form an adhesive layer, but the change in physical properties of the formed adhesive layer over time was very high.

On the other hand, in the case of Comparative Example 5 using the linear acrylic copolymer E having a low weight average molecular weight and Comparative Example 6 using the acrylic copolymer F using oleyl acrylate instead of the monomer represented by Formula 1], the coating viscosity characteristics were good, but , it was found that the aging characteristics of the adhesive layer and the low-temperature and low-humidity durability were poor.

Claims (14)

An acrylic pressure-sensitive adhesive composition comprising an acrylic copolymer formed by polymerizing a monomer mixture including a monomer represented by the following [Formula 1], an alkyl (meth)acrylate-based monomer, and a (meth)acrylic monomer having a crosslinkable functional group,
The monomer mixture contains 12 to 20 parts by weight of the monomer represented by Formula 1 based on 100 parts by weight of the monomer mixture,
An acrylic pressure-sensitive adhesive composition wherein the polymerization conversion rate of the acrylic copolymer is 50% or less.
[Formula 1]

In Formula 1,
R1 and R2 are each independently hydrogen or a C1-C4 alkyl group,
A is a single bond, a C1-C4 alkylene group, an ether, an 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 500,000 g / mol.
According to claim 1,
The monomer represented by [Formula 1] is allyl methacrylate, allyl acrylate, methallyl methacrylate, methallyl acrylate, 3-butenyl Acrylate (3-butenyl acrylate), but-3-enyl-2-methylprop-2-enoate (but-3-enyl-2-methylprop-2-enoate), 2-allyloxyethyl acrylate (2 -allyloxyethyl acrylate), 2-allyloxyethyl methacrylate, 3-allyloxypropyl methacrylate, 3-allyloxypropyl acrylate, 2 - At least one acrylic pressure-sensitive adhesive composition selected from the group consisting of 2-allyloxyethoxyethyl methacrylate and 2-allyloxyethoxyethyl acrylate.
According to claim 1,
The monomer mixture comprises 0.01 to 1 part by weight of the (meth)acrylic monomer having the crosslinkable functional group 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
An acrylic pressure-sensitive adhesive composition comprising 10 to 20 parts by weight of the monomer represented by the above [Chemical Formula 1].
According to claim 1,
The acrylic pressure-sensitive adhesive composition further comprises a multifunctional curing agent.
According to claim 6,
The multifunctional curing agent is at least one acrylic adhesive composition selected from the group consisting of isocyanate-based compounds, epoxy-based compounds, aziridine-based compounds, and metal chelate-based compounds.
According to claim 6,
The multifunctional curing agent is an acrylic pressure-sensitive adhesive composition that is included in 0.001 to 0.1 parts by weight based on 100 parts by weight of the acrylic copolymer.
According to claim 1,
The pressure-sensitive adhesive composition has a solid content of 30% by weight or more,
An acrylic pressure-sensitive adhesive composition having a viscosity of 500 cP to 3000 cP at 23 ° C.
polarizing film; and a pressure-sensitive adhesive layer formed on one or both surfaces of the polarizing film and including a cured product of the acrylic pressure-sensitive adhesive composition according to any one of claims 1 to 9.
According to claim 10,
The polarizing plate has a creep change rate defined by the following formula (1) of 10% or less.
Equation (1): Change rate of slip distance (%) = (T ₀ -T ₁ /T ₀ )×100
In Equation (1), T ₀ is a sliding distance measured after attaching the polarizing plate to a glass substrate to prepare a specimen for measurement, and storing the specimen for measurement at 23 ° C. and 50% RH for 4 days, and T ₁ is the sliding distance measured after storing the specimen for measurement at 23 ° C. and 50% RH for 4 days and additionally aging at 80 ° C. for 1 day.
According to claim 10,
The polarizing plate has 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 above formula (2),
B ₀ was stored for 4 days at 23 ° C. and 50% RH, then stored for 4 hours at 23 ° C. and 50% RH, and then peeled off. Adhesion measured by pulling the polarizing plate under conditions of a speed of 300 mm/min and a peel angle of 180 degrees,
B ₁ stores the specimen for measurement at 23 ° C. and 50% RH for 4 hours, and then further ages it at 80 ° C. for 1 day, and then under the condition of a peeling rate of 300 mm / min and a peeling angle of 180 degrees. It is the adhesive force measured by pulling the polarizer.
According to 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 polarizer of claim 10.