KR102069490B1 - Pressure sensitive adhesive composition - Google Patents

Abstract

The present application relates to an adhesive composition, a polarizing plate, and a liquid crystal display device. In the present application, it is possible to provide an adhesive composition having improved antistatic performance by sufficiently suppressing static electricity generation without changing durability, transparency, adhesive strength, and the like. The pressure-sensitive adhesive composition of the present application can be used, for example, for optical films such as protective films, polarizing plates and the like.

Description

Adhesive composition {PRESSURE SENSITIVE ADHESIVE COMPOSITION}

The present application relates to an adhesive composition, a polarizing plate, and a liquid crystal display device.

Static generation is causing a variety of problems throughout the electronics industry. In addition to mechanical damage, fine dust entering electronic components due to static electricity causes problems such as temporary or permanent damage, malfunction, or process delay. In order to solve this problem, the development of the electronic industry and the improvement of the antistatic technology are continuously required.

For example, in the manufacturing process of a liquid crystal display (LCD), in order to attach a polarizing plate to a liquid crystal panel, it proceeds to the process of removing a release sheet from an adhesive. However, static electricity is generated in this process, affecting the alignment of the liquid crystal of the liquid crystal display device, causing problems in product inspection or damaging the electronic components, thereby causing defects.

Patent document 1 is disclosing the adhesive composition containing an organic type ion salt antistatic agent. However, in order to lower the surface resistance of the pressure-sensitive adhesive using only ionic salts, a large amount of ionic salts must be used, causing precipitation problems of ionic salts and the like.

Patent document 2 is disclosing the optical resin composition which mix | blended the metal salt with the resin composition using the monomer which has a hydrophilic group like ethylene oxide. Patent Literature 2 describes that metal salts provide conductivity, hydrophilic monomers adsorb moisture in the air to lower electrostatic charges, and whitening due to haze can be suppressed even in a high temperature and high humidity environment. However, when the hydrophilic monomer is added to such an extent as to achieve this object, the physical properties of the pressure-sensitive adhesive, in particular, the adhesion and durability are drastically reduced, and the surface resistance of the pressure-sensitive adhesive rapidly rises under high temperature conditions or high temperature and high humidity conditions.

Patent document 3 discloses the adhesive composition containing the ester type antistatic agent which has one or more ether bonds. However, in the case of using such an ester antistatic agent, since a large amount of ionic compounds or metal salts cannot be dissociated, there is a limit in improving the antistatic performance.

Patent Document 1: Republic of Korea Patent Publication No. 2009-0101761 Patent Document 2: Japanese Patent Application Laid-Open No. 2005-031282 Patent Document 3: Republic of Korea Patent Publication No. 2006-0049137

An object of the present application is to provide a pressure-sensitive adhesive composition, a polarizing plate to which the pressure-sensitive adhesive composition is applied, a polarizing plate, and a liquid crystal display device, which sufficiently suppress static electricity generation without changing durability, transparency, adhesive strength, and the like.

The present application 100 parts by weight of the acrylic polymer; 0.01 to 15 parts by weight of a chelating agent having a carbonate group; And it relates to a pressure-sensitive adhesive composition comprising 0. to 15 parts by weight of a ionic compound that is liquid at room temperature or a metal salt that is solid at room temperature.

Hereinafter, the pressure-sensitive adhesive composition will be described in detail.

In one example, the pressure-sensitive adhesive composition may be a pressure-sensitive adhesive for an optical film used for the attachment of the optical film, for example, the adhesion of the polarizing plate and the liquid crystal panel, or between the optical functional film such as a polarizing plate, a retardation plate or a viewing angle expanding film. It can be used for attachment. In another example, the pressure-sensitive adhesive composition may be a pressure-sensitive adhesive composition for polarizing plates used to attach the polarizing plate to the liquid crystal panel.

The pressure-sensitive adhesive composition may include an acrylic polymer. The acrylic polymer may comprise (meth) acrylic acid ester monomers as polymerized units. As said (meth) acrylic acid ester monomer, an alkyl (meth) acrylate can be used, for example. In this case, an alkyl (meth) acrylate having an alkyl group having 1 to 14 carbon atoms can be used in consideration of the cohesion force, glass transition temperature, or adhesiveness of the pressure-sensitive adhesive. Specifically, the monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (Methacrylate, sec-butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, n-octyl (meth) acrylate, iso Octyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate, tetradecyl (meth) acrylate, and the like can be exemplified, and one or two or more of the above are polymerized units It may be included as.

The acrylic polymer may further include a copolymerizable monomer having a crosslinkable functional group as a polymerized unit. The monomer is a monomer which is copolymerized with the aforementioned (meth) acrylic acid ester monomer to be included in the polymer as a polymer unit and can provide a crosslinkable functional group to the side chain or the terminal of the polymer.

As an example of a crosslinkable functional group, nitrogen containing functional groups, such as a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group, or an amino group, etc. are mentioned. Various monomers are known in the manufacturing field of the acrylic polymer, which can play such a role, and all such monomers may be used in the present application. Specific examples of the copolymerizable monomer having a crosslinkable functional group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxy Hydroxy group-containing monomers such as hexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 2-hydroxyethylene glycol (meth) acrylate or 2-hydroxypropylene glycol (meth) acrylate; (Meth) acrylic acid, 2- (meth) acryloyloxy acetic acid, 3- (meth) acryloyloxy propyl acid, 4- (meth) acryloyloxy butyl acid, acrylic acid duplex, itaconic acid, maleic acid and Carboxyl group-containing monomers such as maleic anhydride or nitrogen-containing monomers such as (meth) acrylamide, N-vinyl pyrrolidone or N-vinyl caprolactam, and the like. However, the present invention is not limited thereto.

The copolymerizable monomer having a crosslinkable functional group may be included in a ratio of 0.1 part by weight to 10 parts by weight with respect to 100 parts by weight of the acrylic polymer, thereby effectively controlling physical properties such as durability, adhesive strength and cohesion of the pressure-sensitive adhesive.

In the present specification, the unit "parts by weight" means a weight ratio between components, and thus "parts by weight" and "weight ratio" may be used in the same sense.

If necessary, the acrylic polymer may further include a monomer represented by the following Chemical Formula 1 as a polymerized unit. The monomer of Formula 1 may be added for the purpose of controlling the glass transition temperature and imparting other functionalities.

[Formula 1]

In Formula 1, R ₂ to R ₄ each independently represent hydrogen or alkyl, R ₅ is cyano; Phenyl unsubstituted or substituted with alkyl; Acetyloxy; Or COR ₆ , wherein R ₆ represents amino or glycidyloxy unsubstituted or substituted with alkyl or alkoxyalkyl.

Alkyl or alkoxy in the definition of R ₂ to R ₆ in Formula 1 means alkyl or alkoxy having 1 to 8 carbon atoms, preferably methyl, ethyl, methoxy, ethoxy, propoxy or butoxy.

The monomer of Formula 1 may be included in the polymer in a weight ratio of 20 parts by weight or less, but this may be changed according to the purpose.

The acrylic polymer may be prepared by solution polymerization, photo polymerization, bulk polymerization, suspension polymerization or emulsion of a mixture of monomers blended according to the desired weight ratio of the various polymers described above. It can be prepared by applying to a conventional polymerization method such as polymerization (emulsion polymerization).

The pressure-sensitive adhesive composition may include a chelating agent having a carbonate group. As used herein, the term "chelating agent" may mean a compound having a functional group capable of forming a bond with a metal ion in its molecular structure.

The chelating agent may combine with the cation of an ionic compound or metal salt dissociated into a cation and an anion to form a stabilized chelate complex. Therefore, the anion concentration of the metal salt in the pressure-sensitive adhesive is increased and thereby has ionic conductivity in the pressure-sensitive adhesive composition, and this ion conductivity imparts conductivity to the pressure-sensitive adhesive composition and then adheres to the release film and the adherend of the release film that protects the pressure-sensitive adhesive layer. It is possible to reduce the peeling electrification voltage by reducing the static electricity generated when the protective film is peeled off.

In particular, among the chelating agents, when the chelating agent having a carbonate group is included in the adhesive composition as in the present application, the pressure-sensitive adhesive composition is improved by sufficiently suppressing the generation of static electricity without changing durability, transparency, adhesive strength, and the like. can do.

In one example, the chelating agent having a carbonate group does not react with other additives in the pressure-sensitive adhesive composition, for example, a crosslinking agent or a catalyst and the like, and thus does not reduce the degree of curing of the pressure-sensitive adhesive composition, and thus does not lower the durability reliability of the pressure-sensitive adhesive. The antistatic performance can be improved.

On the other hand, for example, a chelating agent having a diamine group may react with a crosslinking agent having an isocyanate group, and in another example, a chelating agent having a polyvalent carboxyl group may react with a catalyst such as tin. The degree of curing tends to decrease compared to that, and thus, a problem may occur in that the durability of the pressure-sensitive adhesive is lowered.

Moreover, when using the chelating agent which has the said carbonate group, workability | operativity of adhesives, such as re-peelability, can also be effectively maintained by a plasticizing effect. In general, in the case of high pressure-sensitive adhesive, it is necessary to adjust the peelability of the pressure-sensitive adhesive by additionally adding a low molecular weight additive to lower the pressure-sensitive adhesive, while in the case of using a low molecular weight chelating agent as in the present invention, Adhesion can be adjusted without additives.

As the chelating agent having the carbonate group, one having a high solubility in ordinary organic solvents, such as ethyl acetate, toluene, methyl ethyl ketone, acetone, or alcohols, and having excellent compatibility with an acrylic pressure-sensitive adhesive can be used.

In one example, the chelating agent having the carbonate group may be a compound represented by the following formula (2) or formula (3).

[Formula 2]

[Formula 3]

In Formula 2, R ₁ And R ₂ are each independently hydrogen, halogen or an alkyl group having 1 to 10 carbon atoms, and in Formula 3, R ₃ is hydrogen, halogen or an alkyl group having 1 to 5 carbon atoms.

In Formula 2 or 3, the alkyl group may be a linear or branched alkyl group. In Formula 2 or 3, halogen may be fluorine, chlorine, bromine or iodine, and in one specific example, may be fluorine.

Specific examples of the chelating agent having the carbonate group include ethylene carbonate, propylene carbonate, dimethyl carbonate, fluoro ethylene carbonate, ethyl methyl carbonate or diethyl carbonate, and the like, and these may be used alone or in combination of two or more thereof.

According to an embodiment of the present application, the chelating agent having the carbonate group, for example, a compound having a dielectric constant of 30 or more, more specifically, a dielectric constant of 35 or more, 40 or more, 45 or more, 50 or more, 55 or more, or The compound which is 60 or more can be selected and used. As one specific example, ethylene carbonate or propylene carbonate may be used as the chelating agent having the carbonate group. Ethylene carbonate has a dielectric constant of 90 and propylene carbonate has a dielectric constant of 65. Since these compounds have a high dielectric constant, they are excellent in the ability to dissociate cations and anions by removing the coulomb force between cations and anions of ionic compounds or metal salts. Therefore, it is possible to dissociate a large amount of ionic compound or metal salt, thereby increasing the anion concentration of the pressure-sensitive internal metal salt can be given more improved antistatic performance. The higher the dielectric constant, the better the ability to dissociate cations and anions, so the upper limit of the dielectric constant may be appropriately selected within a range that does not impair the object of the present application. For example, the upper limit of the dielectric constant may be 200 or less, 180 or less, 160 or less, 140 or less, 120 or less, or 100 or less. In addition, the dielectric constant may be a value measured by measurement conditions and measurement methods generally used in the art, and may employ the dielectric constant disclosed in literature known in the art. For example, the dielectric constant of the compound may be a dielectric constant disclosed in "Principle and Application of Lithium Secondary Battery, Park Jung-ki, Hong Ryong Science Press, 2010".

When ethylene carbonate is to be used as the chelating agent having the carbonate group, the ethylene carbonate is a solid at room temperature, so different kinds of carbonate chelating agents, for example, dimethyl carbonate may be used in order to make the liquid phase. It is not limited.

The chelating agent having the carbonate group may be included in a ratio of 0.01 to 15 parts by weight with respect to 100 parts by weight of the acrylic polymer. More specifically, the chelating agent having the carbonate group is 0.01 or more, 0.05 or more, 0.1 or more, 0.25 or more, 0.5 or more, 0.75 or more, 1.0 or more, 1.5 or more weight based on 100 parts by weight of the acrylic polymer Or more, 2.0 parts by weight, 3.0 parts by weight, 4.0 parts by weight, 5.0 parts by weight, 6.0 parts by weight, 6.0 parts by weight, 7.0 parts by weight or 8.0 parts by weight or more, and 15 parts by weight or less, 14 parts by weight. Or less, 13 parts by weight, 12 parts by weight or less, 11 parts by weight or less, 10 parts by weight or less, or 9 parts by weight or less. When the content ratio of the chelating agent is within the above range, it is possible to provide a pressure-sensitive adhesive composition having improved antistatic performance by sufficiently suppressing static electricity generation without changing durability, transparency, adhesive strength, and the like.

The pressure-sensitive adhesive composition may also include an ionic compound that is liquid at room temperature. The ionic compound is in liquid phase at room temperature. As used herein, the term "room temperature" is a natural temperature that is not a heated or cooled state, for example, a temperature of about 10 ° C to about 30 ° C, about 15 ° C to about 30 ° C or about 25 ° C. It may mean. By using the ionic compound present in the liquid phase at room temperature, it is possible to ensure excellent antistatic properties while maintaining excellent optical properties, adhesive properties and workability of the pressure-sensitive adhesive. In addition, even when the adhesive is left for a long time or stored, it is possible to prevent changes or deterioration over time such as precipitation of the ionic compound from the adhesive and optical transparency or adhesive physical properties of the adhesive.

The ionic compound may preferably be an organic salt, and in one example quaternary ammonium, phosphonium, pyridinium, imidazolium, pyrolidinium or piperididi It may be an organic salt containing a cationic component such as chromium (piperidinium).

The organic salt may preferably include a quaternary ammonium cation, and in one example may be represented by the following formula (4).

[Formula 4]

In Formula 4, R ₇ to R ₁₀ each independently represent hydrogen, alkyl, alkoxy, alkenyl or alkynyl.

Alkyl or alkoxy in the definition of Chemical Formula 4 may be alkyl or alkoxy having 1 to 20 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms or 1 to 4 carbon atoms. In addition, the alkyl or alkoxy may be linear, branched or cyclic alkyl or alkoxy, and may be optionally substituted with one or more substituents.

In addition, in the definition of Formula 4, alkenyl or alkynyl may be alkenyl or alkynyl having 2 to 20 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms. In addition, the alkenyl or alkynyl may be linear, branched or cyclic alkenyl or alkynyl, and may be optionally substituted with one or more substituents.

When alkyl, alkoxy, alkenyl or alkynyl is substituted with one or more substituents in the definition of Formula 4, examples of the substituent include hydroxy, alkyl, alkoxy, alkenyl, alkynyl, cyano, thiol, amino, aryl Or heteroaryl, and the like, but is not limited thereto.

In one example, R ₇ to R ₁₀ of Chemical Formula 4 may be each independently alkyl, preferably linear or branched alkyl having 1 to 12 carbon atoms, and more preferably R ₇ to R _10. Each of these independently represents straight or branched chain alkyl having 1 to 12 carbon atoms, preferably R ₇ to R ₁₀ are not alkyl having the same carbon number at the same time. That is, in the above example, it is preferable that R ₇ to R ₁₀ are all excluded from the same carbon number alkyl. When R ₇ to R ₁₀ are all alkyl having the same carbon number, the probability that the organic salt is present in the solid phase at room temperature is high.

Specific examples of the cation of Formula 4 include N-ethyl-N, N-dimethyl-N-propylammonium, N, N, N-trimethyl-N-propylammonium, N-methyl-N, N, N-tributyl Ammonium, N-ethyl-N, N, N-tributylammonium, N-methyl-N, N, N-trihexylammonium, N-ethyl-N, N, N-trihexylammonium, N-methyl-N, Or one or more kinds of N, N-trioctyl ammonium or N-ethyl-N, N, N-trioctyl ammonium.

In one example, in Formula 4, R ₇ is alkyl having 1 to 3 carbon atoms, and R ₈ to R ₁₀ are each independently 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms. Cations that are alkyl can be used. By using such a cation, it is possible to provide a pressure-sensitive adhesive having more excellent optical properties, pressure-sensitive adhesive properties, workability and antistatic properties.

As an anion which may be included in the organic salt, an anion represented by the following Formula 5 may be exemplified.

[Formula 5]

[X (YO _m R _f ) _n ] ^-

In Formula 5, X represents nitrogen or carbon, Y represents carbon or sulfur, R _f represents a perfluoroalkyl group, m represents 1 or 2, and n represents 2 or 3.

In Formula 5, when Y is carbon, m is 1, when Y is sulfur, m is 2, n is 2 when X is nitrogen, and n may be 3 when X is carbon.

The anion of Formula 5 may exhibit a high electronegativity due to the perfluoroalkyl group (R _f ), and may also exhibit a high hydrophobicity while forming a weak bond with a cation of Formula 3, including a unique resonance structure. have. Therefore, while an organic salt shows the outstanding compatibility with other components of compositions, such as an acrylic polymer, it can provide high antistatic property even with a small amount.

In one example, R _f of Formula 5 may be a perfluoroalkyl group having 1 to 20 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, in which case the perfluoroalkyl group is linear. It may have a branched or cyclic structure. The anion of Formula 4 may be a sulfonyl metide, sulfonylimide, carbonyl metide, or carbonyl imide anion, and specifically, tristrifluoromethanesulfonylmethide and bistrifluoromethane Sulfonylimide, bisperfluorobutanesulfonylimide, bispentafluoroethanesulfonylimide, tristrifluoromethanecarbonylmethide, bisperfluorobutanecarbonylimide or bispentafluoroethanecarbon It may be one kind or a mixture of two or more kinds such as nilimide.

In one example, the anion of Formula 5 may preferably be bis (perfluoroalkylsulfonylimide), wherein the perfluoroalkyl is perfluoro having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms. It may be alkyl.

The pressure-sensitive adhesive composition may further include a metal salt. In one example, the metal salt may include an alkali metal cation or an alkaline earth metal cation, and preferably may include an alkali metal cation. As such cations, lithium ions (Li ⁺ ), sodium ions (Na ⁺ ), potassium ions (K ⁺ ), rubidium ions (Rb ⁺ ), cesium ions (Cs ⁺ ), beryllium ions (Be ^{2 +} ), magnesium ions (Mg ^{2 +),} calcium ion (Ca ^{+ 2),} strontium ion (Sr ²⁺⁾ and barium ion (Ba ^{+ 2)} there is a iljong or different than the like can be exemplified, preferably lithium in this example One kind or two or more kinds of ions, sodium ions, potassium ions, magnesium ions, calcium ions and barium ions may be used, and lithium ions are more preferably used in consideration of ion stability and mobility in the adhesive, but are not limited thereto. It is not.

As an anion which can be included in the metal salt is a fluoride (F ^-), chloride (Cl ^-), bromide (Br ^-), iodide (I ^-), perchlorate (ClO ₄ ^-), hydroxide (OH ^-) , carbonate (CO ₃ ^2-), nitrate (NO ₃ ^-), trifluoromethane sulfonate (CF ₃ SO ₃ ^-), sulfonate (SO ₄ ^-), hexafluorophosphate (PF ₆ ^-), methyl sulfonate _{(CH 3 (C 6 H 4} ) SO 3 -), p- toluenesulfonate _{(CH 3 C 6 H 4 SO} 3 -), tetraborate (B ₄ O ₇ ^2-), carboxymethyl sulfonate ( _{COOH (C 6 H 4) SO} 3 -), in a triple-sulfonate (CF ₃ SO ₂ ^-), benzo carbonate ^{_{(C 6 H 5 COO -)}} , acetate (CH ₃ COO ^-), acetate in a triple ( CF ₃ COO ^-), tetrafluoroborate (BF ₄ ^-), tetra-benzyl borate _{(B (C 6 H 5)} 4 -) or tris-phosphate, pentafluoroethyl trifluoromethyl _{(P (C 2 F 5)} 3 F ₃ ^-) or the like which may be mentioned include the anion of formula (4) , There are one or two or more can be selected from the aforementioned. In one example, it is preferable to use an imide-based anion which is substituted with fluorine having good role of electron withdrawing and good hydrophobicity and high ion stability, but is not limited thereto.

The pressure-sensitive adhesive composition may include only one of the ionic compound and the metal salt, or may include both the ionic compound and the metal salt. In one example, the weight ratio of the ionic compound and the metal salt in the pressure-sensitive adhesive composition may satisfy the conditions of the following general formula (1).

[Formula 1]

0.1 ≤ A + B ≤ 15

In Formula 1, A is a weight ratio of the ionic compound to 100 parts by weight of the acrylic polymer, and B is a weight ratio of the metal salt to 100 parts by weight of the acrylic polymer.

That is, when the pressure-sensitive adhesive composition includes both the ionic compound and the metal salt, the ionic compound and the metal salt may be included in the pressure-sensitive adhesive composition in a ratio of 0.1 parts by weight to 15 parts by weight based on 100 parts by weight of the acrylic polymer.

If the pressure-sensitive adhesive composition includes only the ionic compound, B in Formula 1 is 0, and the ionic compound may be included in the pressure-sensitive adhesive composition in a ratio of 0.01 parts by weight to 15 parts by weight with respect to 100 parts by weight of the acrylic polymer.

If the pressure-sensitive adhesive composition includes only a metal salt, in Formula 1, A is 0, and the metal salt may be included in the pressure-sensitive adhesive composition in a ratio of 0.01 parts by weight to 15 parts by weight with respect to 100 parts by weight of the acrylic polymer.

 The lower limit of the A + B may be 0.01 or more, 0.05 or more, 0.1 or more, 0.5 or more or 0.1 or more, the upper limit of the total weight is less than 15, 14 or less, 13 or less, 12 or less, 11 or less, 10 or less, 9 or less. , 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, or 3 or less. By adjusting the weight ratio of the ionic compound and the metal salt as described above, it is possible to provide a pressure-sensitive adhesive composition with improved antistatic performance by sufficiently suppressing the generation of static electricity without changing the durability, transparency, adhesion, and the like.

The pressure-sensitive adhesive composition may further include a multifunctional crosslinking agent as a component capable of crosslinking the acrylic polymer in the curing process. As the multifunctional crosslinking agent, for example, an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent or a metal chelate crosslinking agent can be used, and preferably an isocyanate crosslinking agent can be used.

As an isocyanate crosslinking agent, For example, diisocyanate compounds, such as tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoborone diisocyanate, tetramethyl xylene diisocyanate, or naphthalene diisocyanate, Alternatively, a compound obtained by reacting the diisocyanate compound with a polyol may be used, and examples of the polyol include trimethylol propane and the like. As the epoxy crosslinking agent, ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, N, N, N ', N'-tetraglycidyl ethylenediamine and glycerin diglycidyl ether And at least one selected from the group consisting of N, N'-toluene-2,4-bis (1-aziridinecarboxamide), N, N'-diphenylmethane-4, One selected from the group consisting of 4'-bis (1-aziridinecarboxamide), triethylene melamine, bisisoprotaloyl-1- (2-methylaziridine) and tri-1-aziridinylphosphineoxide Although the above is mentioned, it is not limited to this. Examples of the metal chelate crosslinking agent include compounds in which polyvalent metals such as aluminum, iron, zinc, tin, titanium, antimony, magnesium, and / or vanadium are coordinated with acetyl acetone, ethyl acetoacetate, and the like. In the present application, one or more types of crosslinking agents may be used, but the crosslinking agent that may be used in the present application is not limited thereto.

For example, the multifunctional crosslinking agent may be included in the pressure-sensitive adhesive composition in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the acrylic polymer described above. Within such a range, the cohesive force and durability of the pressure-sensitive adhesive can be kept excellent, and storage stability can be improved even when stored for a long time.

The pressure-sensitive adhesive composition may further include a silane coupling agent. The silane coupling agent can improve the adhesion and adhesion stability of the pressure-sensitive adhesive, improve heat resistance and moisture resistance, and also improve the adhesion reliability even when the pressure-sensitive adhesive is left for a long time under severe conditions. As the silane coupling agent, for example, γ-glycidoxypropyl triethoxy silane, γ-glycidoxypropyl trimethoxy silane, γ-glycidoxypropyl methyldiethoxy silane, γ-glycidoxypropyl tri Ethoxy silane, 3-mercaptopropyl trimethoxy silane, vinyltrimethoxysilane, vinyltriethoxy silane, γ-methacryloxypropyl trimethoxy silane, γ-methacryloxy propyl triethoxy silane, γ- Aminopropyl trimethoxy silane, (gamma) -aminopropyl triethoxy silane, etc. can be used, One type or a mixture of 2 or more types of the above can be used.

In one example, the pressure-sensitive adhesive composition may include a silane coupling agent having a β-cyano group or an acetoacetyl group. Examples of the coupling agent include a compound represented by the following Chemical Formula 6 or 7.

[Formula 6]

(R ₁₁ ) _n Si (R ₁₂ ) _(4-n)

[Formula 7]

(R ₁₃ ) _n Si (R ₁₂ ) _(4-n)

In Formula 6 or 7, R ₁₁ represents a β-cyanoacetyl group, R ₁₃ represents an acetoacetyl group or an acetoacetylalkyl group, R ₁₂ represents an alkoxy group, and n represents a number from 1 to 3.

In Formula 6 or 7, alkyl may be alkyl having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms or 1 to 4 carbon atoms, and the alkyl may be linear, branched or cyclic. Can be.

In Formula 6 or 7, alkoxy may be alkoxy having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms or 1 to 4 carbon atoms, and the alkoxy may be linear, branched or cyclic. have.

In addition, n in Chemical Formula 6 or 7 may be preferably 1 to 2, more preferably 1.

As the compound of the formula (6) or (7), for example, acetoacetylpropyl trimethoxy silane, acetoacetylpropyl triethoxy silane, β-cyanoacetyl trimethoxy silane or β-cyanoacetyl triethoxy silane, etc. It may be illustrated, but is not limited thereto.

In the pressure-sensitive adhesive composition, the silane coupling agent may be included in an amount of 0.01 parts by weight to 5 parts by weight, preferably 0.01 parts by weight to 1 parts by weight, with respect to 100 parts by weight of the acrylic polymer. Can be.

The pressure-sensitive adhesive composition may further include a tackifier as necessary. As the tackifier, for example, a hydrocarbon resin or a hydrogenated substance thereof, a rosin resin or a hydrogenated substance thereof, a rosin ester resin or a hydrogenated substance thereof, a terpene resin or a hydrogenated substance thereof, a terpene phenol resin or a hydrogenated substance thereof, a polymerized rosin resin or One kind or a mixture of two or more kinds of polymerized rosin ester resins may be used, but is not limited thereto. The tackifier may be included in the pressure-sensitive adhesive composition at 100 parts by weight or less based on 100 parts by weight of the acrylic polymer.

The pressure-sensitive adhesive composition further includes at least one additive selected from the group consisting of an epoxy resin, a curing agent, an ultraviolet stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, an antifoaming agent, a surfactant, and a plasticizer within a range that does not affect the desired effect. It may further comprise.

The gradually Claim compositions, the surface resistivity was measured after curing the pressure-sensitive adhesive composition was stored for 24 hours under the conditions of 23 ° C and 50% RH with a voltage of 500V after application for one minute can be not more than 1.0 x 10 ¹¹ . Since the said surface resistance is so preferable that it is excellent in antistatic performance, a minimum in particular is not restrict | limited.

As used herein, the term "curing" means a process of changing the pressure-sensitive adhesive composition to a state in which adhesive properties can be expressed through a physical or chemical reaction, and the curing may be, for example, an acrylic polymer contained in the composition and The multifunctional crosslinking agent may be a process of treating the pressure-sensitive adhesive composition under conditions that may cause a crosslinking reaction.

In addition, in this specification, a unit "R.H." means a relative humidity.

The pressure-sensitive adhesive composition has a peel force of 150 gf / 25 mm or more measured at a peel angle of 180 degrees and a peel rate of 0.3 m / min at room temperature after being attached to glass, for example, soda lime glass, in the form of a pressure-sensitive adhesive. Can be. The lower limit of the peeling force may be specifically 175 gf / 25 mm or more, 200 gf / 25 mm or more, 250 gf / 25 mm or more or 300 gf / 25 mm or more. The peel force is, for example, using the pressure-sensitive adhesive composition to prepare a pressure-sensitive adhesive polarizer to be described later, and after attaching the prepared pressure-sensitive polarizer to the glass for 24 hours at a temperature of 23 ° C. and 50% relative humidity Can be measured after standing. By setting the peel force to 150 gf / 25mm or more, in particular, excellent durability as a pressure-sensitive adhesive composition for polarizing plates can be ensured. The upper limit of the peeling force is not particularly limited, but may be adjusted in the range of 2500 gf / 25mm or less, 1500 gf / 25mm or less, or 1000 gf / 25mm or less in consideration of cutting properties and re-peelability.

The present application also provides a polarizer; And an adhesive layer formed on one or both surfaces of the polarizer and used to attach the polarizing plate to the liquid crystal panel, and further comprising the adhesive composition in a cured state.

The polarizer is not particularly limited and may be a general kind known in the art. The polarizer is a functional film that can extract only light vibrating in one direction from incident light while vibrating in various directions. Such a polarizer may be, for example, a form in which a dichroic dye is adsorbed in a polyvinyl alcohol-based resin film. Polyvinyl alcohol-type resin which comprises a polarizer can be obtained by gelatinizing polyvinylacetate-type resin, for example. In this case, the polyvinylacetate-based resin that can be used may include not only a homopolymer of vinyl acetate but also a copolymer of vinyl acetate and other monomers copolymerizable with the above. Examples of the monomer copolymerizable with vinyl acetate include one or two or more kinds of unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids and acrylamides having an ammonium group, but are not limited thereto. no. The polarizer may be produced by stretching the polyvinyl alcohol-based resin film, dyeing with a dichroic dye, or the like, adsorbing the dye, treating the film with an aqueous boric acid solution, and washing with water. As a dichroic dye, iodine, a dichroic organic dye, etc. can be used.

The polarizing plate may further include a protective film attached to one side or both sides of the polarizer, in which case, the pressure-sensitive adhesive layer may be formed on one side of the protective film. The type of protective film is not particularly limited, and includes, for example, a cellulose film such as triacetyl cellulose (TAC); Polyester film such as polycarbonate film or PET (poly (ethylene terephthalet)); Polyether sulfone-based film; Alternatively, a film having a laminated structure of one layer or two or more layers, such as a polyethylene film, a polypropylene film, or a polyolefin-based film produced using a resin having a cyclo or norbornene structure, an ethylene-propylene copolymer, or the like can be used.

The polarizing plate may further include one or more functional layers selected from the group consisting of a protective layer, a reflective layer, an antiglare layer, a retardation plate, a wide viewing angle compensation film, and a brightness enhancing film.

The method for forming the pressure-sensitive adhesive layer on the polarizing plate as described above is not particularly limited, and may be formed by, for example, coating and curing the pressure-sensitive adhesive composition described above. In this process, the pressure-sensitive adhesive composition may be directly coated and cured on the polarizing plate, or coated and cured on the release treatment surface of the release film, and then the polarizing plate may be manufactured by transferring the adhesive composition onto the polarizing plate.

Coating of the pressure-sensitive adhesive composition can be carried out using conventional means such as a bar coater.

In addition, the method of curing the pressure-sensitive adhesive composition is not particularly limited, and, for example, the coating layer may be carried out in such a manner as to maintain the coating layer at an appropriate temperature such that a crosslinking reaction between the acrylic polymer and the multifunctional crosslinking agent contained in the coating layer may be caused. Can be.

The present application also relates to a liquid crystal display device including a liquid crystal panel and the polarizing plate attached to one side or both sides of the liquid crystal panel.

Liquid crystal panels in the apparatus include, for example, passive matrix panels such as twisted nematic (TN) type, super twisted nematic (STN) type, ferroelectic (F) type or polymer dispersed (PD) type; Active matrix panels such as two-terminal or three-terminal; All known panels, such as an In Plane Switching (IPS) panel and a Vertical Alignment (VA) panel, can be applied.

In addition, other configurations of the liquid crystal display device, for example, the upper and lower substrates such as a color filter substrate or an array substrate, are not particularly limited, and configurations known in the art may be employed without limitation.

In the present application, it is possible to provide an adhesive composition having improved antistatic performance by sufficiently suppressing static electricity generation without changing durability, transparency, adhesive strength, and the like. The pressure-sensitive adhesive composition of the present application can be used, for example, for optical films such as protective films, polarizing plates and the like.

Hereinafter, the pressure-sensitive adhesive composition will be described in detail with reference to Examples and Comparative Examples, but the scope of the pressure-sensitive adhesive composition is not limited by the following examples.

Physical properties in this Example and Comparative Example were evaluated in the following manner.

1. Evaluation of Surface Resistance of Adhesive Layer

The pressure-sensitive adhesive polarizing plate on which the pressure-sensitive adhesive was formed was cut to have a length of 50 mm in length, and a specimen was prepared. After removing the release PET adhering to the pressure-sensitive adhesive layer of the specimen, the surface resistance was measured.

Surface resistance was measured according to the manufacturer's manual using an MCP-HT 450 instrument (Mitsubishi Chemical, Japan). Surface resistance was measured after leaving the cut specimens at 23 ° C. and 50% relative humidity for 24 hours to remove the release PET from the polarizer and applying a voltage of 500 volts (V) for 1 minute.

2. Durability Reliability

The polarizing plates prepared in Examples and Comparative Examples were cut to have a width of 180 mm and a length of 220 mm to prepare a specimen, and to attach the specimen to glass. The pressure applied at the time of attachment is about 5 kg / cm ² , and work is performed in a clean room to prevent the inflow of foreign objects or bubbles.

Heat resistance and moisture resistance is evaluated by observing the occurrence of bubbles or peeling after leaving the glass with a polarizing plate attached at 1,000 ° C (temperature and humidity conditions) for 1,000 hours at a temperature of 60 ° C. and 90% relative humidity, heat resistance durability polarizing plate The attached glass is allowed to stand for 1,000 hours (heat-resistant condition) at a temperature of 80 ° C., and then evaluated by observing the occurrence of bubbles or peeling.

The evaluation of the heat-resistant or heat-resistant durability is evaluated after the test specimens are left at the heat-resistant or heat-resistant condition for 24 hours at room temperature.

Durability Evaluation Criteria

○: no bubbles and peeling

Δ: slight bubbles and / or peeling

×: large amount of bubbles and / or peeling

3. Transparency

The transparency of the pressure-sensitive adhesive was visually observed for the pressure-sensitive adhesive after being left to heat or humidity resistant conditions in the durability test, and evaluated according to the following criteria.

<Transparency Evaluation Criteria>

(Circle): When the adhesive is left after the heat-resistant condition is left and the adhesive is transparent after the heat-resistant condition is left

X: When either the pressure-sensitive adhesive after heat-resistant standing and the pressure-sensitive adhesive after heat-resistant heat standing are opaque

4. Peeling force

The pressure-sensitive adhesive polarizing plate prepared in Example or Comparative Example was cut to have a width of 25 mm and a length of 100 mm to prepare a specimen. Next, the release PET film adhered to the pressure-sensitive adhesive layer is peeled off, and the pressure-sensitive adhesive polarizing plate is attached to the soda lime glass using a roller of 2 kg in accordance with JIS Z 0237. Samples were prepared by pressing the glass with a polarizing plate for about 20 minutes in an autoclave (50 ° C., 5 atmospheres) and storing for 24 hours at constant temperature and humidity conditions (23 ° C., 50% relative humidity). Thereafter, the TA force (Texture Analyzer, manufactured by Stable Micro Systems Co., Ltd.) was used to measure the peeling force while peeling the polarizing plate from the glass at a peel rate of 0.3 m / min and a peel angle of 180 degrees.

Preparation Example 1.

96.7 parts by weight of n-butyl acrylate (n-BA), 1.0 part by weight of ethoxy diethylene glycol acrylate, 2-hydroxyethyl acryl in a 1 L reactor equipped with a refrigeration device for easy nitrogen gas reflux and temperature control 2 parts by weight and 0.3 parts by weight of acrylic acid (AA) were added, and 100 parts by weight of ethyl acetate (EAc) was added as a solvent. Thereafter, nitrogen gas was purged for 1 hour for oxygen removal, and the temperature was maintained at 60 ° C. 0.05 parts by weight of AIBN (azobisisobutyronitrile), which is a reaction initiator, was added and reacted. After the reaction, the reaction mixture was diluted with ethyl acetate to prepare an acrylic polymer solution (A1) having a weight average molecular weight of 1.3 million and a solid content concentration of 25% by weight.

Example 1

Preparation of pressure-sensitive adhesive composition (coating liquid)

0.2 weight part of a polyfunctional crosslinking agent (tolylene diisocyanate adduct of trimethylolpropane, TDI-1) with respect to 100 weight part of solid content of the acrylic polymer solution (A1) of manufacture example 1, 2.0 weight part of propylene carbonate (PC) which is a chelating agent, and normal temperature 2 parts by weight of tributylmethylammonium bistrifluorosulfonylimide as a liquid ionic compound, and adjusted to a solid concentration of about 10 to 15% by weight with ethyl acetate to prepare a coating solution (adhesive composition).

Preparation of Adhesion Polarizer

The prepared coating solution is coated on a release treated surface of a PET (poly (ethyleneterephthalate) (MRF-38, Mitsubishi (made)) film subjected to a release treatment so as to have a thickness of 25 μm after drying, and aged under appropriate conditions to form an adhesive layer. The adhesive layer formed was laminated on one surface of the protective film of the iodine polarizing plate to prepare an adhesive polarizing plate.

Examples 2-5 and Comparative Examples 1-5

The pressure-sensitive adhesive composition (coating liquid) and the pressure-sensitive adhesive polarizing plate were manufactured in the same manner as in Example 1 except that the mixing components and compositions were adjusted as shown in Table 1 in the preparation of the pressure-sensitive adhesive composition (coating liquid).

Example Comparative example One 2 3 4 5 One 2 3 4 5 Polymer class A1 Polymer content 100 Crosslinker content 0.2 Chelating content PC 2.0 2.0 0.5 8.0 - - 2.0 2.0 2.0 - EC + DMC
(EC / DMC = 6.4) - - - - 2.0 - - - - - EDA - - - - - - - - - 2.0 Ionic Compound Content 2.0 - - - - - 0.001 - - - Metal salt content - 1.0 1.0 2.0 1.0 1.0 - 15 2.0 1.0 Content unit: parts by weight
Crosslinking agent: Tolylene diisocyanate adduct of trimethylolpropane, TDI-1
PC: propylene carbonate
EC: ethylene carbonate
DMC: Dimethyl Carbonate
EDA: ethyldiamine
Ionic Compound: Tributylmethylammonium Bistrifluorosulfonylimide (at room temperature liquid)
Metal salt: lithium bistrifluorosulfonylimide (solid temperature at room temperature)

Physical property evaluation results for Examples and Comparative Examples are listed in Table 2 and Table 3.

Example One 2 3 4 5 transparency ○ ○ ○ ○ ○ Surface Resistance (Ω / □) 5.6 x 10 ¹⁰ 3.7 x 10 ¹⁰ 9.8 x 10 ¹⁰ 7.4 x 10 ⁹ 3.5 x 10 ¹⁰ durability Heat resistant ○ ○ ○ ○ ○ Heat resistance ○ ○ ○ ○ ○ Peeling force (g / 25mm) 308 333 674 167 327

Comparative example One 2 3 4 5 transparency ○ ○ X ○ ○ Surface Resistance (x 10 ¹⁰ Ω / □) 6.9 x 10 ¹¹ > 10 ¹³ 5.0 x 10 ⁸ 5.7 x 10 ⁹ 8.3 x 10 ¹⁰ durability Heat resistant ○ ○ X X X Heat resistance ○ ○ X X X Peeling force (g / 25mm) 892 368 114 51 344

Claims (18)

Polarizer; A protective film attached to one or both surfaces of the polarizer and an adhesive layer formed on one surface of the protective film,
The pressure-sensitive adhesive layer comprises a pressure-sensitive adhesive composition,
The pressure-sensitive adhesive composition
100 parts by weight of acrylic polymer,
0.01 to 15 parts by weight of a chelating agent having a carbonate group and
0.1 to 15 parts by weight of a ionic compound that is liquid at room temperature or a metal salt that is solid at room temperature,
After the adhesive composition is attached to the glass in a cured state, a polarizing plate having a peel force of 150 gf / 25 mm or more measured at a peel angle of 180 degrees and a peel rate of 0.3 m / min at room temperature. The polarizing plate of claim 1, wherein the acrylic polymer comprises an alkyl (meth) acrylate as a polymerized unit. The polarizing plate of claim 2, wherein the acrylic polymer further comprises 0.1 to 10 parts by weight of the copolymerizable monomer having a crosslinkable functional group as a polymerized unit. The polarizing plate according to claim 3, wherein the crosslinkable functional group is a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group or a nitrogen-containing functional group. The polarizing plate of claim 1, wherein the chelating agent having a carbonate group is a compound represented by the following Chemical Formula 2 or Formula 3:
[Formula 2]

[Formula 3]

In Formula 2, R ₁ and R ₂ are each independently hydrogen, halogen or alkyl group having 1 to 10 carbon atoms, and in Formula 3, R ₃ is hydrogen, halogen or alkyl group having 1 to 5 carbon atoms. The polarizing plate according to claim 1, wherein the chelating agent having a carbonate group contains at least one member selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, fluoro ethylene carbonate, ethylmethyl carbonate and diethyl carbonate. The polarizing plate of claim 1, wherein the chelating agent having a carbonate group has a dielectric constant of 30 or more. The polarizing plate of claim 1, wherein the ionic compound is an organic salt. The polarizing plate of claim 8, wherein the organic salt comprises at least one cation selected from the group consisting of quaternary ammonium, phosphonium, pyridinium, imidazolium, pyrrolidinium, and piperidinium. The polarizing plate of claim 9, wherein the quaternary ammonium is represented by the following Chemical Formula 4:
[Formula 4]

R ₇ to R ₁₀ in Formula 4 are each independently hydrogen, alkyl, alkoxy, alkenyl or alkynyl. The polarizing plate of claim 8, wherein the organic salt comprises an anion represented by Formula 5 below:
[Formula 5]
[X (YO _m R _f ) _n ] ^-
In Formula 5, X represents N or C, Y represents C or S, R _f represents a perfluoroalkyl group, m represents 1 or 2, and n represents 2 or 3. The polarizing plate of claim 1, wherein the metal salt comprises an alkali metal cation or an alkaline earth metal cation. The metal salt of claim 1, wherein the metal salt is fluoride, chloride, bromide, iodide, perchlorate, hydroxide, carbonate, nitrate, trifluoromethanesulfonate, sulfonate, hexafluorophosphate, methylbenzenesulfonate , p-toluenesulfonate, tetraborate, carboxybenzenesulfonate, trichloromethanesulfonate, benzoate, acetate, trifluoroacetate, tetrafluoroborate, tetrabenzylborate, trispentafluoroethyl trifluorophosphate And at least one anion selected from anions represented by Formula 5 below:
[Formula 5]
[X (YO _m R _f ) _n ] ^-
In Formula 5, X represents N or C, Y represents C or S, R _f represents a perfluoroalkyl group, m represents 1 or 2, and n represents 2 or 3. The polarizing plate of claim 1, further comprising 0.01 to 10 parts by weight of a multifunctional crosslinking agent based on 100 parts by weight of the acrylic polymer. The polarizing plate of claim 1, wherein the pressure-sensitive adhesive composition is cured and stored at 23 ° C. and 50% RH for 24 hours, and after applying a voltage of 500 V for 1 minute, a polarizing plate having a surface resistance of 1.0 × 10 ¹¹ or less. delete The polarizing plate of claim 1, wherein the pressure-sensitive adhesive layer is used to attach the polarizing plate to a liquid crystal panel. A liquid crystal display comprising the liquid crystal panel and the polarizing plate of claim 1 attached to one or both surfaces of the liquid crystal panel.