KR20100020119A - Adhesive composition, polarizing plate and surface protective film using the composition - Google Patents

Abstract

PURPOSE: An adhesive composition is provided to prevent the degradation of properties such as stickiness, durability and re-work property, and to ensure excellent antistatic property and optical property. CONSTITUTION: An adhesive composition comprises an adhesive resin, a crosslinking agent, and a conductive polymer polymerized in the presence of organic solvent-dispersible dopant and alkali metal salt as an antistatic agent. The conductive polymer polymerized in the presence of organic solvent-dispersible dopant is included in the amount of 0.0005-0.01 parts by weight based on adhesive resin (solid content standard) 100.0 parts by weight.

Description

Adhesive composition, polarizing plate and surface protection film using the same {ADHESIVE COMPOSITION, POLARIZING PLATE AND SURFACE PROTECTIVE FILM USING THE COMPOSITION}

The present invention relates to a pressure-sensitive adhesive composition, a polarizing plate and a surface protective film using the same, which do not deteriorate physical properties such as durability and rework properties, and which can provide improved optical properties while maintaining excellent antistatic properties.

In general, a liquid crystal display device (LCD) requires a liquid crystal cell and a polarizing plate containing a liquid crystal, and an appropriate adhesive layer or adhesive layer for bonding them should be used.

In addition, the polarizing plate is stretched in a predetermined direction, the polyvinyl alcohol (PVA) polarizer (or 'polarizing film') and the iodine-based compound or dichroic polarizing material adsorbed and oriented to protect both sides of the polarizer It includes a polarizer protective film laminated in order to. Specifically, one side of the polarizer is provided with a polarizer protective film such as triacetyl cellulose (TAC), an adhesive layer and a release film to be affixed with the liquid crystal cell on the protective film, the other side of the polarizer In the polarizer protective film and the base film is composed of a multi-layer provided with a surface protection film laminated pressure-sensitive adhesive layer.

In the process of attaching the polarizing plate having such a structure to the liquid crystal cell, the release film is peeled off from the pressure-sensitive adhesive layer. Since the release film and the surface protection film are made of a plastic material having high electrical insulation, static electricity is generated when the release film is peeled off.

The static electricity generated in this way may cause foreign matter to be adsorbed on the optical member to contaminate the surface, staining due to distortion of the liquid crystal alignment, and may cause breakage of thin film transistor (TFT) lines. In particular, in recent years, as the size of the liquid crystal display panel increases, the size of the polarizing plate also increases accordingly, and as the speed of the process increases, the amount of static electricity is further increased, and more powerful countermeasures are urgently needed to solve the static problem.

In order to solve the static electricity generation problem as described above, a method for imparting antistatic property to the pressure-sensitive adhesive has been proposed. Specifically, a method of adding a substance having a conductive component such as conductive metal powder or carbon particles to the pressure-sensitive adhesive, a method of adding an ionic or nonionic substance in the form of a surfactant, and the like. However, in order to impart antistatic properties, an excessive amount of conductive metal powder or carbon particles must be used, which leads to a problem of deterioration of transparency. Surfactants are susceptible to humidity and deteriorate adhesive properties due to the properties of the adhesive to the surface. There is a problem.

Japanese Laid-Open Patent Publication No. 199-140519 (published on June 6, 1993) discloses a method of adding an ethylene oxide-modified dioctyl-based plasticizer to the inside of an adhesive to provide flexibility, thereby suppressing the generation of static electricity. However, the method has a problem that the transfer to the surface of the polarizing plate occurs, it is difficult to suppress the static electricity generated in the early stage.

Korean Patent Laid-Open Publication No. 2004-0030919 (published on Apr. 9, 2009) discloses a method for preparing a pressure-sensitive adhesive by adding an organic salt and using the same to prepare a pressure-sensitive adhesive layer having a surface specific resistance of 10 ¹³ Ω / □ or less. . However, the method uses excessive amounts of organic salts, and there is a problem in adhesion and durability.

Japanese Laid-Open Patent Publication No. 1994-128539 (published on April 10,199) discloses a method of imparting antistatic properties by blending a polyether polyol and at least one alkali metal salt, but this method has a crosslinking degree when the crosslinking agent is an isocyanate. Not only can it affect, but due to the hydrophilicity of the plasticizer added to the pressure-sensitive adhesive has a problem that can be reduced by the surface transition.

Meanwhile, a method of using a conductive polymer exhibiting electrical conductivity as an antistatic agent through a doping process has been proposed.

Korean Patent Publication No. 2007-0111005 (Nov. 21, 2007) discloses an PDP pressure-sensitive adhesive composition comprising an antistatic agent solution, a crosslinking agent, and an adhesive resin solution composed of a conductive polymer and an organic solvent. However, in order to prepare the composition, the conductive polymer must be dispersed in a pressure-sensitive adhesive resin solution. For this purpose, a time for processing the conductive polymer in an organic solvent is required for 20 to 30 hours, so the processability is low and it is difficult to obtain suitable dispersibility. There was this.

As described above, the conductive polymer should have a property of dissolving or dispersing in the organic solvent for mixing with the pressure-sensitive adhesive composition, but has a very low solubility in the organic solvent due to the strong interaction by the delocalized double bond. have. Conventionally, a method of using a dopant substituted with phosphoric acid, carboxylic acid, or sulfonic acid functional group has been mainly used to increase the solubility of the conductive polymer. There was a problem in that the dopant is de-doped in the conductive polymer backbone under high temperature conditions when used for a long time. In addition, the conductive polymer is used in large amounts to exhibit sufficient antistatic properties, but there was a problem that the optical properties are degraded due to the dark color of the conductive polymer itself.

The present invention does not cause the problem of deterioration of optical properties caused by adding a large amount of conductive polymer to the antistatic agent, without deteriorating the physical properties of the adhesive itself, such as adhesiveness, durability reliability, and reworkability. It is an object of the present invention to provide an adhesive composition capable of satisfying the same.

In another aspect, the present invention is to provide a polarizing plate and a surface protective film laminated pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition.

Another object of the present invention is to provide a liquid crystal display device having the polarizing plate.

In order to achieve the above object, the present invention provides a pressure-sensitive adhesive composition comprising a conductive polymer and an alkali metal salt polymerized in the presence of an organic solvent dispersible dopant with a pressure-sensitive adhesive resin, a crosslinking agent and an antistatic agent.

In another aspect, the present invention provides a polarizing plate and a surface protective film laminated pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition.

In another aspect, the present invention provides a liquid crystal display device provided with the polarizing plate.

According to the present invention, it does not lower the physical properties of the adhesive itself, such as adhesiveness, durability reliability, rework (peel / interlayer adhesion), and there is no problem of compatibility between the antistatic agent and the adhesive resin, and at the same time maintains excellent antistatic property. However, it is possible to provide a pressure-sensitive adhesive composition which can impart improved optical properties by preventing a decrease in transparency due to the dark color of the conductive polymer itself, and a polarizing plate and a surface protection film using the same.

The present invention relates to a pressure-sensitive adhesive composition, a polarizing plate and a surface protective film using the same, which do not deteriorate physical properties such as durability and rework properties, and which can provide improved optical properties while maintaining excellent antistatic properties.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The pressure-sensitive adhesive composition of the present invention is characterized in that it comprises a conductive polymer and an alkali metal salt polymerized in the presence of an organic solvent dispersible dopant with a pressure-sensitive adhesive resin, a crosslinking agent and an antistatic agent.

The adhesive resin is acrylic copolymer, natural rubber, styrene-isoprene-styrene (SIS) block copolymer, styrene-butadiene-styrene (SBS) block copolymer, styrene-ethylenebutylene-styrene (SEBS) block copolymer, styrene- Ordinary polymers, such as butadiene rubber, polybutadiene, polyisoprene, polyisobutylene, butyl rubber, chloroprene rubber and silicone rubber, can be used, and preferably acrylic copolymers can be used.

As an acryl-type copolymer, the copolymer of the monomer which has a functional group which can bridge | crosslink with the (meth) acrylate monomer of C1-C14 of an alkyl group can be used. In this case, (meth) acrylate means both acrylate and methacrylate.

Specific examples of the (meth) acrylate monomer having 1 to 14 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate , n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl ( Meta) acrylate, n-tetradecyl (meth) acrylate, and the like. Among these, when used for a surface protection film, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) Acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n- It is preferable to use the (meth) acrylate monomer of 6-14 carbon atoms of alkyl groups, such as tetradecyl (meth) acrylate, in the point which controls adhesiveness to a to-be-adhered agent low and is excellent in removability.

The (meth) acrylate monomer having 1 to 14 carbon atoms is preferably included in 50 to 99% by weight relative to the total monomer content (100% by weight) used to prepare the acrylic copolymer.

The monomer having a crosslinkable functional group reacts with a crosslinking agent to impart cohesion force or adhesive strength by chemical bonding so that cohesive force breakdown of the pressure sensitive adhesive does not occur under high temperature or high humidity conditions. For example, a sulfonic acid group-containing monomer and a phosphate group-containing monomer are provided. , Cyano group-containing monomers, vinyl esters, aromatic vinyl compounds, carboxyl group-containing monomers, acid anhydride group-containing monomers, hydroxy group-containing monomers, amide group-containing monomers, amino group-containing monomers, imide group-containing monomers, epoxy group-containing monomers, ether group-containing monomers Etc. can be used and these can be used individually or in combination of 2 or more types.

Examples of the sulfonic acid group-containing monomer include styrenesulfonic acid, allylsulfonic acid, 2- (meth) acrylamido-2-methylpropanesulfonic acid, (meth) acrylamidopropanesulfonic acid, sulfopropyl (meth) acrylate, and (meth). Acryloyloxy naphthalene sulfonic acid, sodium vinyl sulfonate, etc. are mentioned.

2-hydroxyethyl acryloyl phosphate is mentioned as said phosphoric acid group containing monomer.

(Meth) acrylonitrile is mentioned as said cyano group containing monomer.

Examples of the vinyl esters include vinyl acetate, vinyl propionate and vinyl laurate.

Examples of the aromatic vinyl compound include styrene, chlorostyrene, chloromethylstyrene, α-methylstyrene, and other substituted styrenes.

Examples of the carboxyl group-containing monomers include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid and isocrotonic acid.

As said acid anhydride containing monomer, maleic anhydride, itaconic anhydride, these acid anhydrides, etc. are mentioned.

As said hydroxyl group containing monomer, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate , 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl acrylate, N- Methylol (meth) acrylamide, vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, etc. are mentioned.

Examples of the amide group-containing monomer include (meth) acrylamide, diethylacrylamide, N-vinylpyrrolidone, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N'-methylenebisacrylamide, N, N- dimethylaminopropyl (meth) acrylamide, diacetone acrylamide, etc. are mentioned.

Examples of the amino group-containing monomers include aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, and (meth) acryloyl morpholine. Can be mentioned.

Cyclohexyl maleimide, isopropyl maleimide, N-cyclohexyl maleimide, itaciconimide etc. are mentioned as said imide group containing monomer.

Examples of the epoxy group-containing monomers include glycidyl (meth) acrylate, methylglycidyl (meth) acrylate, allyl glycidyl ether, and the like.

The ether group-containing monomers include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, and acryloyl. Morpholine, and the like.

The monomer having a crosslinkable functional group is preferably contained in 1 to 50% by weight relative to the total monomer content (100% by weight) used in the production of the acrylic copolymer.

The acrylic copolymer composed of the above components can be prepared by conventional methods such as solution polymerization, photopolymerization, bulk polymerization, suspension polymerization and emulsion polymerization, and preferably by solution polymerization.

The acrylic copolymer has a weight average molecular weight (polystyrene equivalent) measured by gel permeation chromatography (GPC) method is usually 50,000 to 2,000,000, preferably 100,000 to 1,800,000, more preferably 500,000 to 1,500,000 to be.

The crosslinking agent is used to reinforce the cohesive force of the pressure-sensitive adhesive by appropriately crosslinking the acrylic copolymer, and an isocyanate compound, an epoxy compound, a melamine resin, an aziridine compound, or the like can be used, and preferably an isocyanate compound or an epoxy compound can be used. have. These can be used individually or in combination of 2 or more types.

As said isocyanate compound, tolylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, 2, 4- diphenyl methane diisocyanate, 4, 4- diphenyl methane diisocyanate, isophorone diisocyanate, tetramethyl xylene diisocyanate And naphthalene diisocyanate.

Examples of the epoxy compound include ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, N, N, N ', N'-tetraglycidyl diamine, glycerin diglycidyl ether, and 1 , 3-bis (N, N- diglycidylaminomethyl) cyclohexane, etc. are mentioned.

Hexamethylol melamine is mentioned as said melamine type resin.

Examples of the aziridine-based compound include N, N'-toluene-2,4-bis (1-aziridinecarboxide) and N, N'-diphenylmethane-4,4'-bis (1-aziridinecarboxa) Id), triethylene melamine, bisisoprotaloyl-1- (2-methylaziridine), tri-1-aziridinylphosphine oxide, etc. are mentioned.

The crosslinking agent is preferably included in 0.01 to 15 parts by weight based on 100 parts by weight of the pressure-sensitive adhesive resin (based on the solid content). If the content is less than 0.01 parts by weight, the adhesive force or cohesive force of the pressure-sensitive adhesive is not good, and if it exceeds 15 parts by weight, the compatibility is reduced, the surface migration may occur and the crosslinking reaction is too advanced to reduce the adhesive strength.

In addition, as said crosslinking agent, an ultraviolet curable polyfunctional (meth) acrylate type monomer can also be used. As a specific example, 1, 4- butanediol di (meth) acrylate, 1, 6- hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethyleneglycol di (meth) acrylate, dicyclo Fentanyldi (meth) acrylate, caprolactone modified dicyclopentenyldi (meth) acrylate, ethylene oxide modified phosphoric acid di (meth) acrylate, di (acryloxyethyl) isocyanurate, allylated cyclohexyldi (meth) 2) such as acrylate, dimethylol dicyclopentane diacrylate, ethylene oxide modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol acrylate, neopentyl glycol modified trimethylolpropane diacrylate and adamantane diacrylate Functional monomers; Trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane Trifunctional monomers such as tri (meth) acrylate and tris (acryloxyethyl) isocyanurate; Tetrafunctional monomers such as diglycerin tetra (meth) acrylate and pentaerythritol tetra (meth) acrylate; Pentafunctional monomers such as propionic acid-modified dipentaerythritol penta (meth) acrylate; And 6 functional monomers, such as caprolactone modified dipentaerythritol hexa (meth) acrylate, etc. are mentioned. These can be used individually or in combination of 2 or more types.

The ultraviolet curable polyfunctional (meth) acrylate-based monomer is preferably included in 0.1 to 30 parts by weight based on 100 parts by weight of the pressure-sensitive adhesive resin (based on the solid content).

The ultraviolet curable polyfunctional (meth) acrylate-based monomer may be used together with a photopolymerization initiator that generates radicals or cations by irradiation with ultraviolet rays.

Specific examples of the photoinitiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2, 2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl Ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propane-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2- Propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2- Aminoanthraquinone, 2-methyl thioxanthone, 2-ethyl thioxanthone, 2-chlorothioxanthone, 2,4-dimethyl thioxanthone, 2,4-diethyl thioxanthone, benzyl dimethyl ketal, acetophenone Dimethyl ketal, p-dimethylaminobenzoic acid LE and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and the like, and these may be used alone or in combination of two or more. The photopolymerization initiator may be included in an amount of usually 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the pressure-sensitive adhesive resin (based on the solid content).

The antistatic agent preferably includes both the conductive polymer polymerized in the presence of the organic solvent dispersible dopant and an alkali metal salt.

Conductive polymers that are antistatic agents are, in particular, conductive polymers polymerized in the presence of organic solvent dispersible dopants. Here, the 'organic solvent dispersible dopant' refers to a dopant which is an anionic surfactant used in the polymerization of the conductive polymer, and the conductive polymer polymerized using the organic polymer disperses in the organic solvent.

More specifically, the conductive polymer polymerized in the presence of the organic solvent dispersible dopant of the present invention polymerizes the monomer for polymerizing the conductive polymer in the presence of an anionic surfactant as a dopant, and the dopant is doped with an ionic bond to the conductive polymer. As the charge is balanced, it stabilizes the polaron of the conductive polymer main chain, so that the dispersibility of the organic solvent is excellent and there is no de-doping phenomenon.

The conductive polymer may be at least one selected from the group consisting of polythiophene, polyacetylene, polyaniline, polypyrrole, polyphenylene, and derivatives thereof polymerized in the presence of an organic solvent dispersible dopant, and is easy to manufacture and has excellent conductivity. More preferred is poly (3,4-ethylenedioxythiophene) (EDOT).

As the organic solvent dispersible dopant, one or more compounds selected from the group consisting of compounds of Formulas 1 to 6 may be used.

In Chemical Formulas 1 to 6, the substituent R is a hydrocarbon group having 4 to 18 carbon atoms, for example, an alkyl group having 4 to 18 carbon atoms, an isoalkyl group, an alkoxy group, an alkoxyalkyl group, an alkylsulfonyl group, an alkoxysulfonyl group, or an alkylsilane. Group or alkoxysilane group. The substituents X may be the same or different, and each may be one substituent selected from the group consisting of a sulfonate group, a carboxylate group, a phosphate group, a cyanate group and a silicate group, preferably a sulfonate group. In addition, M may be one metal or ammonium selected from the group consisting of Li, Na and K, and n is an integer of 1 to 20.

The organic solvent dispersable dopant as described above may be added to water, which is a solvent, and stirred, followed by addition and polymerization of a conductive polymer polymerization monomer, an initiator, and an oxidizing agent, thereby preparing a conductive polymer.

The organic solvent dispersible dopant may be used in an amount of 1 to 600 parts by weight based on 100 parts by weight of the monomer used for the polymerization of the conductive polymer.

In addition, the organic solvent dispersible dopant is preferably pH of 5.0 to 6.5 in order to ensure effective doping of the dopant to the conductive polymer and the ideal mechanical strength of the polymerized conductive polymer.

The oxidizing agent may be used paratoluene iron sulfate (III), metatoluene iron sulfate (III), trifluororosulfate iron (III) or iron sulfate (III), etc., the total reactants used for the polymerization of the conductive polymer It can be used in less than 40 parts by weight.

As described above, the conductive polymer polymerized in the presence of the organic solvent dispersible dopant has excellent compatibility with the acrylic copolymer, which is a pressure-sensitive adhesive resin, so that there is no problem such as surface migration and impart antistatic property with durability of the pressure-sensitive adhesive. In addition, it can exhibit excellent antistatic properties unique to the conductive polymer. On the other hand, when the organic solvent dispersible dopant is added after the conductive polymer is prepared without being added at the time of polymerization of the conductive polymer, the doping by the ionic bond of the dopant and the conductive polymer is not performed well, even if doped. Not only is it less likely to be de-doped when used for a long time at a high temperature can be transferred to the surface when applied to the pressure-sensitive adhesive layer.

An example of the structure of poly (3,4-ethylenedioxythiophene) (EDOT) polymerized in the presence of the organic solvent dispersible dopant may be represented by the following Chemical Formula 7, but is not limited thereto. In general, for the structural analysis, the separation of the compound should be possible. However, when the polymer is prepared by polymerization, it is difficult to identify the exact structure formed. Also, as in the present invention, the portion of the organic polymer dispersable dopant doped during the polymerization of the conductive polymer is a conductive polymer. It is difficult to specify the structure of the final conductive polymer because it will depend on where the unlocalized double bond is located.

Wherein AS ⁻ is an organic solvent dispersible dopant.

The conductive polymer may be included in an amount of 0.0005 to 0.01 parts by weight, preferably 0.001 to 0.005 parts by weight, based on 100 parts by weight of the pressure-sensitive adhesive resin (based on the solid content). If the content is less than 0.0005 parts by weight, the effect of imparting antistatic properties may be insignificant, and if it exceeds 0.01 parts by weight, the transparency of the pressure-sensitive adhesive layer may be poor due to the color peculiar to the conductive polymer, thereby reducing the optical properties.

Alkali metal salt as an antistatic agent is a metal salt included with the conductive polymer polymerized in the presence of an organic solvent dispersible dopant, and prevents the problem of transparency deterioration caused by the use of a large amount of the conductive polymer for the desired antistatic property. It is used to improve the optical characteristics at the same time.

The alkali metal salt is a salt formed by a combination of a cation and an anion, and may be a lithium salt (Li), sodium salt (Na), or potassium salt (K). Specific examples include lithium iodide (LiI), lithium perchlorate (LiClO ₄ ), sodium perchlorate (NaClO ₄ ), potassium perchlorate (KClO ₄ ), lithium hexafluoroalsenate (LiAsF ₆ ), lithium tetrafluoroborate (LiBF ₄₎ ), Lithium hexafluorophosphate (LiPF ₆ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), bis (trifluoromethanesulfonyl) imide lithium (LiN (CF ₃ SO ₂ ) ₂ ), tris ( Trifluoromethanesulfonyl) methidilithium (LiC (CF ₃ SO ₂ ) ₃ ), bis (fluorosulfonyl) imide lithium (LiN (FSO ₂ ) ₂ ), bis (fluorosulfonyl) imide potassium (KaN (FSO ₂ ) ₂ ), bis (fluorosulfonyl) imide sodium (NaN (FSO ₂ ) ₂ ), and the like, and these may be used alone or in combination of two or more thereof.

The alkali metal salt is a material that exhibits ion conduction by dissociating ions, and if the content thereof is too small, the antistatic property is not good. If the alkali metal salt is contained in an excessive amount, the antistatic property is slowed down and the durability of the pressure sensitive adhesive is reduced due to the deterioration of the thermal stability of the metal salt. Can lower the temperature and cause deterioration. Therefore, the alkali metal salt is preferably contained in an amount of 0.05 to 0.25 parts by weight, and more preferably 0.1 to 0.2 parts by weight based on 100 parts by weight of the pressure-sensitive adhesive resin (based on the solid content).

In the present invention, the antistatic agent may be a solution further comprising an organic solvent. The organic solvent is used to improve the dispersibility in applying the conductive polymer polymerized in the presence of the organic solvent dispersible dopant to the pressure-sensitive adhesive resin among antistatic agents. That is, by dissolving (dispersing) the polymerized conductive polymer in an organic solvent and then applying it to the adhesive resin, there is no problem in compatibility between the polymerized conductive polymer and the adhesive resin, thereby improving antistatic properties.

Examples of the organic solvent include alcohols, acetates, ethers, ketones, aromatic hydrocarbons, halogenated hydrocarbons and cyclic esters, and these may be used alone or in combination of two or more thereof as a mixed solvent. Specific examples include n-butanol, butyl acetate, carbon tetrachloride, chloroform, 1,2-dichloroethane, dichloromethane, ethyl acetate, diethyl ether, methyl-t-butyl ether, methyl ethyl ketone, acetone, diisopropyl Ether, toluene, trichloroethylene and the like. More preferably, it is ethyl acetate, methyl ethyl ketone, or acetone in consideration of compatibility with the solvent used for manufacture of an adhesive resin.

The content of the organic solvent is not particularly limited and may be included in a content capable of sufficiently dissolving the conductive polymer polymerized in the presence of the organic solvent dispersible dopant. As a specific example, it is preferable that it is 50-3000 weight part with respect to 100 weight part (solid content basis) polymerized in the presence of an organic solvent dispersible dopant, More preferably, it is 100-1000 weight part.

The pressure-sensitive adhesive composition containing the above components may further include a surfactant such as an amine compound or a quaternary salt compound.

In addition, the pressure-sensitive adhesive composition may further include a silane coupling agent as necessary in order to improve the adhesion when the adhesive composition and the liquid crystal cell or substrate.

Specific examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxy silane, methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropyltriethoxysilane , 3-mercaptopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, etc. are mentioned, These can be used individually or in combination of 2 or more types. The silane coupling agent may be included in an amount of 0.005 to 5 parts by weight based on 100 parts by weight of the pressure-sensitive adhesive resin (based on the solid content).

In addition, the pressure-sensitive adhesive composition is a tackifying resin, antioxidant, corrosion inhibitor, leveling agent, surface lubricant, dye, pigment, antifoaming agent, filler in order to adjust the adhesion, cohesion, viscosity, elastic modulus, glass transition temperature, etc. required according to the application It may further include additives such as plasticizers or light stabilizers.

The pressure-sensitive adhesive composition can be used both as a polarizing plate or a surface protective film pressure-sensitive adhesive. Also, it can be used as protective film, reflective sheet, structural adhesive sheet, photo adhesive sheet, lane marking adhesive sheet, optical adhesive product, adhesive for electronic parts, as well as general commercial adhesive sheet product and medical patch.

Polarizing plate of the present invention is characterized in that the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition is laminated.

The polarizing plate includes a polarizer (or “polarizing film”), and on one side of the polarizer, a polarizer protective film for protecting the polarizer, a pressure-sensitive adhesive layer and a release film, which are combined with the liquid crystal cell, are sequentially stacked. The other side of the polarizer is a multilayer structure provided with a polarizer protective film.

As said polarizer, the thing in which the dichroic dye was adsorption-oriented to the film which consists of polyvinyl alcohol-type resin can be used. As a polyvinyl alcohol-type resin which comprises the said polarizer, the copolymer etc. of polyvinyl acetate which is a homopolymer of vinyl acetate, a vinyl acetate, and the other monomer copolymerizable with this can be used. In this case, examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, vinyl ethers, and acrylamides having an ammonium group. The thickness of the polarizer is not particularly limited, and may be manufactured to a conventional thickness.

The polarizer protective film is preferably excellent in transparency, mechanical strength, thermal stability, moisture shielding, isotropy, etc., for example, polyester-based films such as polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate; Cellulose films such as diacetyl cellulose and triacetyl cellulose; Polycarbonate film; Acrylic films such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene films such as polystyrene and acrylonitrile-styrene copolymers; Polyolefin-based films such as polyethylene, polypropylene, cyclo- or polyolefin-based films having a norbornene structure, and ethylene propylene copolymers; Polyimide film; Polyether sulfone-based film; A sulfone film etc. can be used, The thickness of these is also not specifically limited.

The release film is a film for protecting the pressure-sensitive adhesive layer, the type is not particularly limited as long as it is a film commonly used in the art. Specific examples include polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-vinyl acetate copolymer, ethylene-ethylacrylic Polyolefin type films, such as a rate copolymer and an ethylene-vinyl alcohol copolymer; Polyester-based films such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate; Polyamide films such as polyacrylate, polystyrene, nylon 6 and partially aromatic polyamide; Polyvinyl chloride film; Polyvinylidene chloride film; Or polycarbonate films. These can also be used by appropriately releasing a silicone, fluorine or silica powder.

The method of laminating the pressure-sensitive adhesive layer on the polarizing plate is not particularly limited as long as it is a method commonly used in the art. For example, the pressure-sensitive adhesive composition may be flow casted on a polarizer protective film, and a bar coater, air knife, gravure, reverse roll, kiss roll, spray Using a coating method, such as (spray) or blade (blade) method can be directly applied in a suitable development method, dried and laminated. In addition, after forming a pressure-sensitive adhesive layer by forming the pressure-sensitive adhesive layer on the silicone-coated release film by the same coating method as described above, it may be laminated on the polarizer protective film using a roll pressing device. At this time, when the ultraviolet-curable polyfunctional (meth) acrylate monomer is included as a crosslinking agent in the pressure-sensitive adhesive composition, it is preferable to irradiate ultraviolet rays after applying the pressure-sensitive adhesive composition or laminating it on the polarizer protective film using a roll pressing device. .

The thickness of the pressure-sensitive adhesive layer can be adjusted according to the adhesive force, it is usually preferably 3 to 100㎛, more preferably 10 to 100㎛.

The polarizing plate may be applied to all of the conventional liquid crystal display devices, and specifically, the liquid crystal display device may include a liquid crystal panel in which a polarizing plate on which an adhesive layer is laminated is bonded to one side or both sides of a liquid crystal cell.

Surface protection film of the present invention is a film for protecting the outermost layer of the optical film, in particular the polarizing plate, characterized in that the pressure-sensitive adhesive layer and the release film made of the pressure-sensitive adhesive composition on the base film sequentially laminated.

A base film is used as a base material for laminating an adhesive layer, Polycarbonate film; Polyester-based films such as polyethylene terephthalate; Polyether sulfone-based film; Or polyolefin films such as polyethylene, polypropylene, cyclo or norbornene structures, polyolefin films such as ethylene propylene copolymers, and the like. At this time, in order to improve adhesiveness with an adhesive, you may surface-treat or primer-treat on one side or both sides of a base film.

The release film is a film for protecting the pressure-sensitive adhesive layer, the same as that used in the polarizing plate may be used.

The method of laminating the pressure-sensitive adhesive layer on the base film may be the same method as the method of laminating the pressure-sensitive adhesive layer on the polarizing plate.

The thickness of the pressure-sensitive adhesive layer can be adjusted according to the adhesive force, it is usually 2 to 100㎛, preferably 5 to 50㎛.

The surface protection film is applicable to both optical members such as polarizing plates and ordinary liquid crystal display devices.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. It is natural that such variations and modifications fall within the scope of the appended claims.

In the following Preparation Examples, Examples and Comparative Examples, "%" and "parts" indicating the contents are by weight unless otherwise specified.

Production Example  1. Preparation of pressure-sensitive adhesive resin

A 4-neck jacket reactor (1L) was equipped with a stirrer, a thermometer, a reflux condenser, a dropping lot, and a nitrogen gas inlet tube. Nitrogen gas was added to the reactor for replacement, and then 164 parts of ethyl acetate, n- 126 parts of butyl acrylate, 0.5 part of acrylic acid, and 1.3 part of # 2-hydroxyethyl acrylate were thrown in, and the reactor external temperature was heated up at 50 degreeC. Then, a solution in which 0.14 parts of 2,2'-azobisisobutyronitrile (AIBN) was completely dissolved in 10 parts of ethyl acetate was added dropwise to the reactor. After the reaction was continued for an additional 5 hours while maintaining the jacket outside temperature at 50 ° C, 90 parts of ethyl acetate was slowly added dropwise using a dropping lot for 1 hour. In addition, after additional stirring for 6 hours at the same temperature, 304 parts of ethyl acetate was added and stirred for 2 hours to obtain a final acrylic copolymer. The prepared acrylic copolymer had a solid content of 20% and a weight average molecular weight (in terms of polystyrene) by GPC method was about 1,500,000.

Preparation Example 2 Preparation of Conductive Polymer

2.5L of distilled water and 31% of sodium lauryl sulfate (SLS) were added to a 5L reactor equipped with a stirrer and a nitrogen filling device and stirred at room temperature. The reactor was replaced with nitrogen for 30 minutes, followed by dropwise addition of 28.1 g (0.2 mol) of 3,4-ethylenedioxythiophene, 66 g (0.27 mol) of sodium persulfate and 0.5 g (125 mmol) of iron sulfate. Proceeded. The reaction mixture was stirred at 25 ° C. for 24 hours and then passed through an ion exchange resin (300 mL Lewatit ^™ S100MB + 500 mL Lewatit ^™ M600MB) twice to remove residual initiator and oxidant ions. Further, the mixture was stirred at 90 ° C. for 1 hour to polymerize poly (3,4-ethylenedioxythiophene), a conductive polymer, and then to the polymerized poly (3,4-ethylenedioxyti) by adding 250 g of ethyl acetate (EA) thereto. Offen) was extracted to prepare a conductive polymer.

Example 1

100 parts of acrylic pressure sensitive adhesive resin (based on solid content) prepared in Preparation Example 1, 0.8 parts of trimethylolpropane-modified tolylene diisocyanate (Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.), and 3-glycidoxy, a silane coupling agent 0.15 parts of propyltrimethoxysilane (KBM403, manufactured by Shin-Etsu Co., Ltd.), 0.005 parts of conductive polymer (based on solid content) prepared in Preparation Example 2 as an antistatic agent, and 0.1 parts of lithium iodide (LiI) (based on solid content) The pressure-sensitive adhesive composition was prepared by diluting to an appropriate concentration with acetate.

The prepared pressure-sensitive adhesive composition was applied on a polyethylene terephthalate film (41 cm × 34 cm) coated with a silicone release agent to have a dry film thickness of 25 μm, and dried at 100 ° C. for 1 minute to form a pressure-sensitive adhesive layer. The polarizing plate was laminated on a conventional polarizing plate to prepare a plurality of polarizing plates coated with an adhesive, and was cured at 25 ° C. and 50% relative humidity for 7 days.

Example 2

Except for using 0.001 parts of a conductive polymer (based on solids content) and 0.1 part of lithium iodide (LiI) (based on solids content) as an antistatic agent, the same process as in Example 1 was carried out.

Example 3

The same method as in Example 1 was conducted except that 0.001 parts of a conductive polymer (based on a solid content) and 0.2 parts of lithium iodide (LiI) (based on a solid content) were used as an antistatic agent.

Example 4

Except for using 0.005 parts of the conductive polymer (based on the solid content) and 0.2 parts of lithium iodide (LiI) (based on the solids content) as the antistatic agent was carried out in the same manner as in Example 1.

Comparative Example 1

The same method as in Example 1 was carried out except that only conductive polymer (based on solids content) was used as an antistatic agent at 0.005 parts.

Comparative Example 2

The same method as in Example 1 was carried out except that only conductive polymer (based on solids content) was used as an antistatic agent in an amount of 0.05 part.

Comparative Example 3

The same procedure as in Example 1 was carried out except that only 0.30 part of lithium iodide (based on solids content) was used as an antistatic agent.

division Adhesive resin Crosslinking agent Silane coupling agent Antistatic agent COR-L KBM-403 Poly (3,4-ethylenedioxythiophene) LiI Example 1 100 0.8 0.15 0.005 0.1 Example 2 100 0.8 0.15 0.001 0.1 Example 3 100 0.8 0.15 0.001 0.2 Example 4 100 0.8 0.15 0.005 0.2 Comparative Example 1 100 0.8 0.15 0.005 - Comparative Example 2 100 0.8 0.15 0.05 - Comparative Example 3 100 0.8 0.15 - 0.3

Test Example

The physical properties of the pressure-sensitive adhesive composition and pressure-sensitive adhesive layer prepared in Examples and Comparative Examples were measured by the following method, and the results are shown in Tables 2 and 3 below.

* Surface resistivity (Ω / □)

-Measuring instrument: Surface resistance measuring instrument (MCP-HT450 / MITSUBISHI CHEMICAL)

Probe (URS, UR100), Probe Checker (for URS, UR 100)

Measurement method: After peeling off the PET film, three points on the surface of the pressure-sensitive adhesive layer were measured 10 times, respectively, and the average values were represented.

* Saturated saturation voltage (kV) and large voltage half-life (sec)

-Measuring instrument: Static electricity research equipment (STATIC HONESTMETER Type H-0110 / SHISHIDO ELECTRONSTATIC)

Measurement method: The prepared polarizing plate was cut into 3 cm x 3 cm to prepare a specimen, and after peeling off the PET film, it was mounted on a holder and measured three times under the following conditions, and the average value was represented.

Applied voltage: 10kV, 30 seconds

Voltage application height: 2cm

* Optical characteristic

After applying the prepared pressure-sensitive adhesive composition on a transparent optical film, the color was visually observed and evaluated based on the following criteria.

(Circle): It shows transparent and little color, and there is no fall of optical characteristic (transmittance).

X: Strong blue color and optical characteristic (transmittance) fall.

* Durability Reliability

The prepared polarizing plate sheet was cut to 300 mm × 220 mm, and then bonded to Corning's # 1737 glass to prepare a specimen. The prepared specimens were treated in an autoclave for 5 minutes at 50 ° C. for 20 minutes and then left in an oven at 60 ° C. and 90% relative humidity for 300 hours. Peeling phenomena such as lifting and peeling of the specimen left undisturbed and bubbles were visually confirmed, and evaluated based on the following criteria.

○: No peeling phenomenon or bubbles (good)

×: peeling phenomenon and bubbles are generated (defect)

* Reworkability (Adhesion / Interlayer Adhesion)

The prepared polarizing plate sheet was cut to have a length of 200 mm and a width of 25 mm, and then bonded to Corning # 1737 glass to prepare a specimen. After the prepared specimens were treated in an autoclave for 5 minutes at 50 ° C. for 20 minutes, the polarizers were peeled off from the glass of the specimens left at room temperature for 24 hours and the specimens left at 60 ° C. for 4 hours. The presence of an adhesive layer (antistatic coating layer) was visually observed and evaluated based on the following criteria.

○: no adhesive layer remained during peeling (good)

(Triangle | delta): The adhesive layer remains 10% or less at the time of peeling (usually)

X: 50% or more of adhesive layers remain in peeling (defect)

division Surface resistivity (Ω / □) Optical properties Durability Reliability Reworkability Example 1 1.3 × 10 ¹¹ ○ ○ ○ Comparative Example 1 5.3 × 10 ¹³ ○ ○ ○ Comparative Example 2 7.0 × 10 ¹⁰ × ○ △ Comparative Example 3 1.3 × 10 ¹¹ ○ × ×

division Surface resistivity (Ω / □) Saturation to Voltage (kv) Half-life (seconds) Example 1 1.3 × 10 ¹¹ 1.86 1.17 Example 2 6.5 × 10 ¹¹ 2.70 3.89 Example 3 2.8 × 10 ¹¹ 2.47 1.34 Example 4 9.8 × 10 ¹⁰ 1.65 0.85

As shown in Tables 2 and 3, the pressure-sensitive adhesive layer of Example 1 is excellent in the optical effect by suppressing the decrease in transparency due to the color of the conductive polymer as well as antistatic properties, and excellent in durability and rework resistance. On the other hand, Comparative Example 1 containing only a small amount of conductive polymer was difficult to obtain sufficient antistatic property, Comparative Example 2 containing only a large amount of conductive polymer to solve this problem, the antistatic property is improved, but the adhesive layer shows a strong blue transparency Was lowered and as a result the optical properties were lowered. In Comparative Example 3 containing only an alkali metal salt instead of the conductive polymer, the antistatic property was improved, but the durability and rework resistance were greatly reduced.

In addition, according to the present invention, the pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition of Examples 1 to 4 including both the conductive polymer polymerized in the presence of an organic solvent dispersible dopant and an alkali metal salt as an antistatic agent has a surface specific resistance of 10 ¹¹ (Ω / □). The following values were obtained to obtain a sufficient antistatic effect. The low saturation voltage and the short half-life can effectively suppress the generation of static electricity due to peeling of the release film. In particular, in the case of Example 4, not only the surface resistivity but also the saturation voltage and the half-life were very excellent.

Claims (12)

An adhesive composition comprising a conductive polymer and an alkali metal salt polymerized in the presence of an organic solvent dispersible dopant with an adhesive resin, a crosslinking agent, and an antistatic agent. The method of claim 1, wherein the conductive polymer polymerized in the presence of the organic solvent dispersible dopant is included in 0.0005 to 0.01 parts by weight based on 100 parts by weight of the pressure-sensitive adhesive resin (based on the solid content), the alkali metal salt is contained in 0.05 to 0.25 parts by weight Pressure-sensitive adhesive composition. The conductive polymer of claim 2, wherein the conductive polymer polymerized in the presence of the organic solvent dispersible dopant is included in an amount of 0.001 to 0.005 parts by weight based on 100 parts by weight of the pressure sensitive adhesive resin (based on a solid content), and the alkali metal salt is included in an amount of 0.1 to 0.2 parts by weight. Pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition of claim 1, wherein the conductive polymer is at least one selected from the group consisting of polythiophene, polyacetylene, polyaniline, polypyrrole, polyphenylene, and derivatives thereof polymerized in the presence of an organic solvent dispersible dopant. The pressure-sensitive adhesive composition of claim 1, wherein the organic solvent dispersible dopant is at least one selected from the group consisting of Formulas 1 to 6. [Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

[Chemical Formula 5]

[Formula 6]

[Wherein R is a hydrocarbon group of 4 to 18 carbon atoms, X may be the same or different and is one substituent selected from the group consisting of sulfonate group, carboxylate group, phosphate group, cyanate group and silicate group , M is one metal or ammonium selected from the group consisting of Li, Na and K, n is an integer from 1 to 20]. The pressure-sensitive adhesive composition of claim 1, wherein the organic solvent dispersible dopant is included in an amount of 1 to 600 parts by weight based on 100 parts by weight of the monomer used for the polymerization of the conductive polymer. The pressure-sensitive adhesive composition of claim 1, wherein the conductive polymer is poly (3,4-ethylenedioxythiophene) polymerized in the presence of an organic solvent dispersible dopant. The method of claim 1, wherein the alkali metal salt is lithium iodide (LiI), lithium perchlorate (LiClO ₄ ), sodium perchlorate (NaClO ₄ ), potassium perchlorate (KClO ₄ ), lithium hexafluoroacenate (LiAsF ₆ ), lithium tetra Fluoroborate (LiBF ₄ ), Lithium hexafluorophosphate (LiPF ₆ ), Lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), Bis (trifluoromethanesulfonyl) imide lithium (LiN (CF ₃ SO ₂₎ ) ₂ ), tris (trifluoromethanesulfonyl) methirithium (LiC (CF ₃ SO ₂ ) ₃ ), bis (fluorosulfonyl) imide lithium (LiN (FSO ₂ ) ₂ ), bis (fluoro Sulfonyl) imide potassium (KaN (FSO ₂ ) ₂ ) and bis (fluorosulfonyl) imide sodium (NaN (FSO ₂ ) ₂ ) pressure-sensitive adhesive composition selected from the group consisting of. The method of claim 1, wherein the antistatic agent is n-butanol, butyl acetate, carbon tetrachloride, chloroform, 1,2-dichloroethane, dichloromethane, ethyl acetate, diethyl ether, methyl t-butyl ether, methyl ethyl ketone , Acetone, diisopropyl ether, toluene and trichloroethylene pressure-sensitive adhesive composition which is a solution containing at least one organic solvent selected from the group consisting of. The polarizing plate in which the adhesive layer which consists of an adhesive composition of any one of Claims 1-9 was laminated | stacked. The surface protection film laminated | stacked the adhesive layer which consists of an adhesive composition of any one of Claims 1-9. A liquid crystal display device comprising a polarizing plate according to claim 10 on at least one side of a liquid crystal cell.