KR101455301B1 - Adhesive composition and polarizing plate using the composition - Google Patents

Abstract

The present invention relates to a pressure-sensitive adhesive composition and a polarizing plate using the pressure-sensitive adhesive composition, and more particularly, to a pressure-sensitive adhesive composition which comprises an acrylic copolymer, an ultraviolet curable compound, a photopolymerization initiator, a crosslinking agent and an antistatic agent represented by the following general formula Sensitive adhesive composition capable of sufficiently preventing the generation of static electricity and improving the antistatic property and also being easily re-peelable and having little dimensional change to improve the light leakage phenomenon, and a polarizing plate using the same.

M ⁺ [(FSO ₂ ) ₂ N] ^-

Wherein M is an alkali metal.

Antistatic property, light leakage, polarizer, adhesive

Description

TECHNICAL FIELD [0001] The present invention relates to a pressure-sensitive adhesive composition and a polarizer using the same. BACKGROUND ART [0002]

The present invention relates to a pressure-sensitive adhesive composition capable of not only lowering the physical properties of the pressure-sensitive adhesive itself but also improving antistatic properties and light leakage phenomenon, and a polarizing plate using the pressure-sensitive adhesive composition.

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

The polarizing plate may further include a polyvinyl alcohol (PVA) polarizer (or a polarizing film) that is stretched in a predetermined direction and in which an iodine compound or a dichroic polarizing material is adsorbed and oriented, and a polarizer And a polarizer protective film laminated thereon. Specifically, on one side of the polarizer, a polarizer protective film such as triacetyl cellulose (TAC), a pressure sensitive adhesive layer and a release film which are to be in contact with the liquid crystal cell on the protective film, A polarizer protective film and a surface protective film having a pressure-sensitive adhesive layer laminated on the base film.

In the process of adhering the polarizing plate having such a structure to the liquid crystal cell, the release film is peeled off from the pressure-sensitive adhesive layer, and when the surface protective film plays a role in the post-process, it is also peeled off. Since the release film and the surface protection film are made of a plastic material, they have high electrical insulation and generate static electricity when they are peeled off.

The static electricity generated in this way causes a problem of contamination of the surface due to adsorption of foreign matter on the optical member, a problem of staining due to distortion of the alignment of the liquid crystal, and the like, and there is a fear of damaging the thin film transistor (TFT) line. Particularly, in recent years, as the size of a liquid crystal display panel has been enlarged, the size of a polarizing plate used for manufacturing a liquid crystal display has also been enlarged, and the speed of the process has been increased, so that the amount of static electricity has been increased.

In order to solve the problem of generation of static electricity as described above, a method of imparting antistatic property to a pressure-sensitive adhesive has been proposed. Specifically, there are a method of adding a substance having a conductive component such as a conductive metal powder or carbon particles to a 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, there is a problem that transparency is lowered due to the use of excessive amounts of conductive metal powder or carbon particles, and surfactants tend to be affected by humidity and have a problem of deteriorating adhesive properties .

Japanese Patent Application Laid-Open No. 1993-140519 (published on Jun. 6, 1993) discloses a method of suppressing the generation of static electricity by adding ethylene oxide modified phthalic acid dioctyl plasticizer to the inside of the pressure sensitive adhesive to give flexibility. However, the above method has a problem of transferring to the surface of the polarizing plate, and it is difficult to suppress the static electricity generated at the initial stage.

Korean Patent Laid-Open Publication No. 2004-0030919 (published on April 9, 2004) discloses a method of preparing a pressure-sensitive adhesive by adding an organic salt and using the pressure-sensitive adhesive to produce a pressure-sensitive adhesive layer having a surface resistivity of 10 ¹³ Ω / . However, the above method has problems in that the organic salt is excessively used, resulting in poor adhesion and durability.

Japanese Patent Laid-Open Publication No. 1994-128539 (published on May 5, 1994) discloses a method for imparting antistatic property by blending a polyether polyol and at least one alkali metal salt. However, this method is not suitable for crosslinking even when isocyanate is used But also has a problem that the surface properties of the plasticizer may be degraded due to the hydrophilicity of the plasticizer.

On the other hand, since the polarizing plate in which the pressure-sensitive adhesive layer is laminated is made of a material having a different molecular structure and composition, the dimensional stability due to changes in the external environment is insufficient. Particularly, under heat or humid conditions, dimensional stability due to shrinkage or expansion of materials with a certain molecular arrangement is insufficient. Therefore, when the polarizing plate is fixed by the pressure-sensitive adhesive, a dimensional change occurs and a strain stress remains Which causes a light leakage phenomenon in which light is leaked or easily stained in a portion where stress is concentrated.

The pressure sensitive adhesive composition may be softened or hardened in order to solve the light leakage phenomenon as described above. However, in the conventional isocyanate crosslinking, there is a limitation in softening or hardening while maintaining the adhesive property, Absorption, and relaxation. As another method, there has been proposed a method of improving the stress relaxation property according to the dimensional change of the polarizing plate by adding an additive to the pressure-sensitive adhesive composition. In addition, by using high molecular weight and low molecular weight polymer in the pressure- (Japanese Patent Laid-Open No. 2000-109771). However, this method can not sufficiently prevent light leakage.

In addition, since the use field of the liquid crystal display device is expected to be further expanded in the future, even if the amount of dimensional change of the substrate is increased due to the increasing static electricity generation problem and the worse conditions, There is a demand for a pressure-sensitive adhesive composition which can be improved together.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a polarizing plate which is excellent in antistatic property when applied to a liquid crystal display device, And to provide a pressure-sensitive adhesive composition capable of minimizing the rate of dimensional change with respect to the light-shielding layer and improving the light leakage phenomenon.

Another object of the present invention is to provide a polarizing plate in which a pressure-sensitive adhesive layer composed of the pressure-sensitive adhesive composition is laminated.

It is another object of the present invention to provide a liquid crystal display device provided with the polarizer.

In order to achieve the above object, the present invention provides a pressure-sensitive adhesive composition comprising an acrylic copolymer, an ultraviolet curable compound, a photopolymerization initiator, a crosslinking agent, and an antistatic agent represented by the following general formula:

[Chemical Formula 1]

M ⁺ [(FSO ₂ ) ₂ N] ^-

Wherein M is an alkali metal.

The present invention also provides a polarizing plate in which a pressure-sensitive adhesive layer composed of the pressure-sensitive adhesive composition is laminated.

The present invention also provides a liquid crystal display having the polarizing plate on at least one side of a liquid crystal cell.

According to the present invention, it is possible to sufficiently suppress the generation of static electricity without deteriorating the physical properties of the pressure-sensitive adhesive itself, such as tackiness and durability, to improve antistatic property, And a polarizing plate and a liquid crystal display using the same.

The present invention relates to a pressure-sensitive adhesive composition capable of not only lowering the physical properties of the pressure-sensitive adhesive itself but also improving antistatic properties and light leakage phenomenon, and a polarizing plate using the pressure-sensitive adhesive composition.

Hereinafter, the present invention will be described in detail.

The pressure-sensitive adhesive composition of the present invention is characterized by containing an acrylic copolymer, an ultraviolet curable compound, a photopolymerization initiator, a crosslinking agent and an antistatic agent represented by the following general formula (1).

[Chemical Formula 1]

M ⁺ [(FSO ₂ ) ₂ N] ^-

Wherein M is an alkali metal.

Typically, the pressure-sensitive adhesive resin includes an acrylic copolymer, a natural rubber, a styrene-isoprene-styrene (SIS) block copolymer, a styrene-butadiene-styrene (SBS) block copolymer, a styrene-ethylene butylene- , Styrene-butadiene rubber, polybutadiene, polyisoprene, polyisobutylene, butyl rubber, chloroprene rubber, and silicone rubber. Among them, an acrylic copolymer is preferable when it is applied to a polarizing plate.

As the acrylic copolymer, a copolymer of a (meth) acrylate monomer having an alkyl group of 1 to 14 carbon atoms and a monomer having a crosslinkable functional group can be used. Here, (meth) acrylate means both acrylate and methacrylate.

Specific examples of the (meth) acrylate monomers having 1 to 14 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s- (Meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) acrylate, n-decyl (meth) acrylate, n-decyl (meth) acrylate, isononyl ) Acrylate, and n-tetradecyl (meth) acrylate. (Meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, (Meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (Meth) acrylate monomer having 6 to 14 carbon atoms in the alkyl group is preferable because the adhesive force to the adherend is controlled to be low and the re-peeling property is excellent.

The (meth) acrylate monomer having 1 to 14 carbon atoms is preferably contained in an amount of 50 to 99% by weight based on the total monomer content (100% by weight) used in the production of the acrylic copolymer.

The monomer having a crosslinkable functional group reacts with a crosslinking agent to give a cohesive force or a cohesive strength by chemical bonding so that the cohesive force of the pressure sensitive adhesive does not break under high temperature or high humidity conditions. For example, the monomer having a sulfonic acid group- , An amino group-containing monomer, an imide group-containing monomer, an epoxy group-containing monomer, an ether group-containing monomer, a carboxyl group-containing monomer, a carboxyl group-containing monomer, a cyano group-containing monomer, a vinyl ester, an aromatic vinyl compound, These may be used alone or in combination of two or more.

Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allylsulfonic acid, 2- (meth) acrylamido-2-methylpropanesulfonic acid, (meth) acrylamidopropanesulfonic acid, sulfopropyl (meth) Acryloyloxynaphthalenesulfonic acid, sodium vinylsulfonate, and the like.

As the phosphate group-containing monomer, 2-hydroxyethyl acryloyl phosphate can be mentioned.

Examples of the cyano group-containing monomer include (meth) acrylonitrile.

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

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

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

Examples of the acid anhydride-containing monomer include maleic anhydride, itaconic anhydride, and acid anhydrides thereof.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (Meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) (Meth) acrylamide, vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether and the like.

Examples of the amide group-containing monomer include (meth) acrylamide, diethylacrylamide, N-vinylpyrrolidone, N, N-dimethyl (meth) acrylamide, N, N'-methylenebisacrylamide, N, N-dimethylaminopropyl (meth) acrylamide, diacetone acrylamide and the like.

Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, (meth) acryloylmorpholine, .

Examples of the imide group-containing monomer include cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide and itaconimide.

Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, and allyl glycidyl ether.

Examples of the ether group-containing monomer include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, phenoxyethyl And morpholine.

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

The acrylic copolymer having the above components may be prepared by a conventional method such as a solution polymerization method, a photopolymerization method, a bulk polymerization method, a suspension polymerization method and an emulsion polymerization method, and is preferably prepared by a solution polymerization method.

The acrylic copolymer generally has a weight average molecular weight (in terms of polystyrene) measured by Gel Permeation Chromatography (GPC) of usually 50,000 to 2,000,000, preferably 100,000 to 1,800,000, more preferably 500,000 to 1,800,000, 1,500,000.

The ultraviolet ray curable compound is used for improving the releasability of the pressure-sensitive adhesive layer and improving the storage elastic modulus (G ') to minimize the rate of dimensional change with respect to exposure to the external environment to improve the light leakage phenomenon. Metha) acrylate monomer.

Specific examples of the polyfunctional (meth) acrylate monomer include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) (Meth) acrylates such as polyethylene glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified di (Meth) acrylate, dimethylolcyclohexane diacrylate, ethylene oxide modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol acrylate, neopentyl glycol-modified trimethylolpropane diacrylate Bifunctional monomers such as acrylate and adamantanediyl acrylate; (Meth) acrylate such as trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri 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 hexafunctional monomers such as caprolactone-modified dipentaerythritol hexa (meth) acrylate. These may be used alone or in combination of two or more.

As the ultraviolet curable compound, a (meth) acrylate oligomer may also be used. The (meth) acrylate oligomer preferably has a weight average molecular weight of 50,000 or less. Specific examples thereof include polyester (meth) acrylate, epoxy (meth) acrylate, urethane ) Acrylates, polybutadiene (meth) acrylates, and silicone (meth) acrylates.

As the ultraviolet curable compound, the above-mentioned polyfunctional (meth) acrylate monomer and (meth) acrylate oligomer may be used alone, or two or more of these may be used in combination.

In the present invention, the acrylic copolymer and the ultraviolet curable compound are preferably contained in a weight ratio of 100: 5 to 100: 50, more preferably 100: 10 to 100:40, and most preferably 100: 15 to 100 : 30 weight ratio. When the weight ratio is less than 100: 5, sufficient crosslinking density can not be obtained and the storage elastic modulus is low, so that the dimensional change can not be sufficiently suppressed. When the weight ratio is more than 100: 50, the crosslinking density is too high, The adhesive property is deteriorated.

The ultraviolet curable polyfunctional (meth) acrylate monomer may be used in combination with a photopolymerization initiator that generates radicals or cations by irradiation with ultraviolet light.

Specific examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 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-propan- ) Ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methyl anthraquinone, 2-ethyl anthraquinone, 2- Anthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetophenone dimethyl Ketal, p-dimethylaminobenzoate And 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide. These may be used alone or in combination of two or more. The photopolymerization initiator may be contained in an amount of 0.2 to 20 parts by weight based on 100 parts by weight of the ultraviolet curable compound.

The crosslinking agent is an isocyanate compound, an epoxy compound, a melamine resin, an aziridine compound or the like which is used for reinforcing the cohesive force of the pressure-sensitive adhesive by suitably crosslinking the acrylic copolymer, and preferably an isocyanate compound or an epoxy compound can be used have. These may be used alone or in combination of two or more.

Examples of the isocyanate compound include tolylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, 2,4-diphenylmethane diisocyanate, 4,4-diphenylmethane diisocyanate, isophorone diisocyanate, Naphthalene diisocyanate, and the like.

Examples of the epoxy compound include ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, N, N, N ', N'-tetraglycidyldiamine, glycerin diglycidyl ether, , 3-bis (N, N-diglycidylaminomethyl) cyclohexane, and the like.

Examples of the melamine resin include hexamethylol melamine.

Examples of the aziridine compound include N, N'-toluene-2,4-bis (1-aziridinecarboxamide), N, N'-diphenylmethane-4,4'- Id), triethylene melamine, bisisopropanoyl-1- (2-methyl aziridine), and tri-1-aziridinyl phosphine oxide.

The crosslinking agent is preferably contained in an amount of 0.01 to 15 parts by weight based on 100 parts by weight of the acrylic copolymer (based on the solid content). If the content is less than 0.01 part by weight, the adhesive force or the cohesive force of the pressure-sensitive adhesive is not good. If the content exceeds 15 parts by weight, the compatibility may decrease and surface migration may occur.

The antistatic agent is preferably a metal salt represented by the general formula (1) comprising an alkali metal cation and a bis (fluorosulfonyl) imide anion.

[Chemical Formula 1]

M ⁺ [(FSO ₂ ) ₂ N] ^-

Wherein M is an alkali metal.

The alkali metal may be one selected from the group consisting of lithium, sodium, potassium and cesium, preferably lithium, sodium or potassium.

The antistatic agent has a high degree of electronegativity with respect to the fluorine atoms of the anion and has a low coordination bond to the alkali metal cations and high hydrophobicity, so that it is excellent in compatibility with the acrylic copolymer, has no planar surface, Thereby imparting physical properties. Compared with perfluorinated alkylsulfonylimides, they exhibit more excellent antistatic properties because they have a small anion radius and are free to move in the pressure sensitive adhesive.

The content of the antistatic agent is not particularly limited and is preferably 0.01 to 10 parts by weight, more preferably 0.02 to 7 parts by weight, and most preferably 0.01 to 10 parts by weight based on 100 parts by weight of the acrylic copolymer (based on the solid content) 0.3 to 5 parts by weight. If the content is less than 0.01 part by weight, the antistatic effect may be insufficient. If the content is more than 10 parts by weight, the cohesiveness of the pressure-sensitive adhesive may be poor and the durability may be deteriorated.

The pressure-sensitive adhesive composition containing the above-mentioned components may further contain a silane coupling agent as needed in order to improve the adhesiveness with the liquid crystal cell or substrate.

Specific examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane , 3-mercaptopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane and the like, which may be used alone or in combination of two or more. The silane coupling agent may be contained in an amount of 0.005 to 5 parts by weight based on 100 parts by weight of the acrylic copolymer (based on the solid content).

The pressure-sensitive adhesive composition may further contain additives such as a tackifier resin, an antioxidant, a corrosion inhibitor, a leveling agent, a surface lubricant, a dye, a pigment, an antifoaming agent, a filler, and the like to control the adhesion, cohesion, viscosity, , A plasticizer, or a light stabilizer.

The pressure-sensitive adhesive composition may be used as a pressure-sensitive adhesive for a polarizing plate. Further, it can be used not only as a protective film, a reflective sheet, a structural adhesive sheet, a photographic adhesive sheet, a lane marking adhesive sheet, an optical adhesive product, an electronic component adhesive, a general commercial adhesive sheet product, and a medical patch.

The pressure-sensitive adhesive composition is preferably cured by ultraviolet irradiation, and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive composition preferably has a storage elastic modulus (G ') of 0.5 to 10 MPa at 23 ° C. When the storage elastic modulus (G ') is less than 0.5 MPa, it is difficult to improve the light leakage phenomenon due to the small rate of change in the amount of exposure to the external environment. When the storage elastic modulus (G') is more than 10 MPa, the pressure sensitive adhesive is too hard to be applied to attach the polarizing plate to the liquid crystal cell Durability is impaired.

The polarizing plate of the present invention is characterized in that a pressure-sensitive adhesive layer composed of the above pressure-sensitive adhesive composition is laminated.

The polarizing plate includes a polarizer (or a polarizing film), a polarizer protective film for protecting the polarizer, a pressure-sensitive adhesive layer to be in contact with the liquid crystal cell, and a release film are sequentially laminated on one side of the polarizer, And a polarizer protective film is provided on the other surface of the polarizer.

As the polarizer, a film made of a polyvinyl alcohol resin and having a dichromatic dye adsorbed and oriented can be used. As the polyvinyl alcohol-based resin constituting the polarizer, a copolymer of vinyl acetate, which is a homopolymer of vinyl acetate, and vinyl acetate and other monomer copolymerizable therewith, may be used. Examples of other monomers copolymerizable with vinyl acetate at this time 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 can be made in a usual thickness.

The polarizer protective film is preferably excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy and the like, and examples thereof include polyester films such as polyethylene terephthalate, polyethylene isophthalate and polybutylene terephthalate; Cellulose-based films such as diacetylcellulose and triacetylcellulose; Polycarbonate film; Acrylic films such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene-based films such as polystyrene and acrylonitrile-styrene copolymer; Polyolefin-based films such as polyethylene, polypropylene, cyclo-based or norbornene-based polyolefin-based films, and ethylene propylene copolymers; Polyimide-based films; Polyethersulfone-based films; A sulfone-based film, and the like, and their thickness is not particularly limited.

The release film is a film for protecting the pressure-sensitive adhesive layer, and the kind thereof is not particularly limited as long as it is a film ordinarily used in the art. Specific examples thereof include polyolefins such as polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene- A polyolefin-based film such as an ethylene-vinyl alcohol copolymer; Polyester films such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate; Polyamide-based films such as polyacrylate, polystyrene, nylon 6, and partially aromatic polyamide; Polyvinyl chloride films; Polyvinylidene chloride films; Or a polycarbonate film. These may be appropriately subjected to a releasing treatment by a silicone system, a fluorine system, a silica powder, or the like.

The pressure-sensitive adhesive layer is composed of the above pressure-sensitive adhesive composition, and has a storage elastic modulus (G ') of 0.5 to 10 MPa at 23 占 폚.

The method for 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 applied on a silicone-coated release film by a flow casting method and a bar coater, an air knife, a gravure, a reverse roll, a kiss roll ), A spray or a blade method, drying it by a suitable developing method, drying it, and laminating it with a polarizing plate, and then irradiating ultraviolet rays from the release film side. Further, a pressure-sensitive adhesive layer was formed on the silicone-coated release film by the same application method as described above to prepare a pressure-sensitive adhesive sheet, and a coated silicone release film having a different peeling force was laminated thereon using a roll- To prepare a pressure-sensitive adhesive transfer tape, and adhering it to a polarizing plate.

The ultraviolet ray may be obtained from a high-pressure mercury lamp, an electrodeless lamp, a xenon lamp, or the like. Although not ultraviolet ray, it is one of energy radiation such as ultraviolet ray, and an electron ray obtained from an electron beam accelerator or the like may be used, but it is more preferable to use ultraviolet ray. The irradiation dose of ultraviolet rays can be arbitrarily selected within a range in which the storage elastic modulus (G ') of the pressure-sensitive adhesive layer and the adhesive force to the alkali-free glass and polycarbonate can be obtained. For example, in the case of ultraviolet rays, the illuminance is preferably 50 to 1,000 mW / cm 2, the light quantity is 50 to 1,000 mJ / cm 2, and the electron beam preferably has an absorbed dose of 10 to 1,000 krad.

The liquid crystal display of the present invention is characterized in that a polarizing plate having the pressure-sensitive adhesive layer laminated on at least one surface of a liquid crystal cell is provided.

In the present invention, since the liquid crystal display device is well known to those skilled in the art, a detailed description thereof will be omitted.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

In the following Production Examples, Examples and Comparative Examples, '%' and 'part' indicating the content are based on weight unless otherwise specified.

Production Example 1. Preparation of acrylic copolymer (A-1)

A n-butyl acrylate (n-BA) 97 part, an acrylic acid (AA) solution, and a nitrogen gas introducing tube were placed in a 1-L reactor of a 4-neck jacket equipped with a stirrer, a thermometer, a reflux condenser, , 120 parts of ethyl acetate and 0.1 part of azobisisobutyronitrile (AIBN) were put in a reactor, and air in the reactor was replaced with nitrogen gas. The temperature of the reaction solution was raised to 66 캜 under stirring in a nitrogen gas atmosphere, and the reaction was carried out for 10 hours. After completion of the reaction, the reaction mixture was diluted with ethyl acetate to obtain an acrylic copolymer (A-1) solution having a solid content of 20% by weight. The weight average molecular weight (Mw) of the obtained acrylic copolymer (A-1) by GPC was 1,100,000.

Production Example 2. Preparation of acrylic copolymer (A-2)

Except that 78 parts of n-butyl acrylate (n-BA), 20 parts of methyl acrylate (MA), 1 part of 2-hydroxyethyl acrylate (HEA) and 1 part of acrylic acid (AA) (A-2) solution having a solid content of 20% by weight was obtained in the same manner as in Example 1. The weight average molecular weight (Mw) of the acrylic copolymer (A-2) prepared by GPC was 1,000,000.

Example 1

100 parts of the acrylic copolymer (A-1) (based on the solids content), 20 parts of trimethylolpropane triacrylate (B-1), 20 parts of a photopolymerization initiator (benzophenone: 1-hydroxycyclohexyl phenyl ketone = 1: ), 0.4 part of a crosslinking agent, 0.5 part of tolylene diisocyanate (Coronate-L, manufactured by Nippon Polyurethane Industry Co., Ltd.), 0.1 part of 3-glycidoxypropyltrimethoxysilane (KBM403, Shinetsu) 0.3 part of KN (FSO ₂ ) ₂ was added and diluted with ethyl acetate to an appropriate concentration to prepare a pressure-sensitive adhesive composition.

The pressure-sensitive adhesive composition thus prepared was coated on a polyethylene terephthalate film (41 cm x 34 cm) coated with silicone release agent to a dry film thickness of 25 m and dried at 100 deg. C for 1 minute to form a pressure-sensitive adhesive layer. A conventional polarizing plate was laminated thereon, and then light-cured by irradiation with ultraviolet rays. A plurality of polarizing plate adhesive sheets thus prepared were cured in a curing oven at 25 ° C and a relative humidity of 50% for 7 days. At this time, the ultraviolet ray irradiation was carried out at an illuminance of 600 mW / cm 2 and a light intensity of 150 mJ / cm 2 using an electrodeless lamp-H valve (manufactured by Fusion Co., Ltd.). Ultraviolet light and an illuminance light meter were irradiated with ultraviolet ray PF-36 (EYEGRAPHICS Co., Ltd.) was used.

Examples 2 to 11 and Comparative Examples 1 to 5

A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1, except that the ingredients and the contents shown in Table 1 were used, and a polarizing plate adhesive sheet was prepared using the same.

The components and content of the pressure-sensitive adhesive composition prepared in the above Examples and Comparative Examples are shown in Table 1 below. Here, the content of each component represents parts by weight.

division Acrylic copolymer UV curable compound Light curing
Initiator Cross-linking agent
(COR-L) Silane
Coupling agent
(KBM403) Antistatic agent Kinds content Kinds content KN (FSO ₂ ) ₂ LiI LiClO ₄ Ionic liquid Example
One A-1 100 B-1 20 0.4 0.5 0.1 0.3 - - - Example
2 A-1 100 B-2 20 0.4 0.5 0.1 0.3 - - - Example
3 A-1 100 B-3 20 0.4 0.5 0.1 0.3 - - - Example
4 A-2 100 B-1 15 0.3 0.5 0.1 0.3 - - - Example
5 A-2 100 B-2 15 0.3 0.5 0.1 0.3 - - - Example
6 A-2 100 B-3 15 0.3 0.5 0.1 0.3 - - - Example
7 A-1 100 B-1 20 0.4 0.5 0.1 0.02 - - - Example
8 A-1 100 B-1 20 0.4 0.5 0.1 0.1 - - - Example
9 A-1 100 B-1 20 0.4 0.5 0.1 One - - - Example
10 A-1 100 B-1 20 0.4 0.5 0.1 2 - - - Example
11 A-1 100 B-1 20 0.4 0.5 0.1 5 - - - Comparative Example
One A-1 100 - - - 3 0.1 0.3 - - - Comparative Example
2 A-2 100 - - - 0.5 0.1 0.3 - - - Comparative Example
3 A-1 100 B-1 20 0.4 0.5 0.1 - 0.3 - - Comparative Example
4 A-1 100 B-1 20 0.4 0.5 0.1 - - 0.3 - Comparative Example
5 A-1 100 B-1 20 0.4 0.5 0.1 - - - 0.3

A-1: Acrylic copolymer (BA: AA = 97: 3)

A-2: Acrylic copolymer (BA: MA: HEA: AA = 78: 20: 1:

B-1: trimethylolpropane triacrylate (Mw: 296) (KS-TMPTA, manufactured by Sartomer)

B-2: Tris (acryloxyethyl) isocyanurate (Mw: 423.3) (Aronix M-315, manufactured by TOAGOSEI)

B-3: dipentaerythritol hexaacrylate (Mw: 578.6) (KAYARADDPHA, manufactured by NIPPON KAYAKU)

Photopolymerization initiator: benzophenone / 1-hydroxycyclohexyl phenyl ketone (1: 1) (Irgacure 500, manufactured by Chiba Specialty Chemicals)

Crosslinking agent: Tolylene diisocyanate (Coronate-L, manufactured by Nippon Polyurethane Industry Co., Ltd.)

Silane coupling agent: 3-glycidoxypropyltrimethoxysilane (KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.)

Ionic liquid: 1-hexyl-4-methylpyridinium hexafluorophosphate (IL-P14-2, manufactured by Kokusa Chemical Co., Ltd.)

Test Example

The physical properties of the polarizing plate-adhered sheets prepared in the Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 2 below.

* Surface resistivity (Ω / □)

Meter: Surface Resistance Meter (MCP-HT450 / MITSUBISHI CHEMICAL)

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

Measurement method: The release film of the pressure-sensitive adhesive sheet was peeled off, and the three points on the surface were measured ten times each, and the average value was measured.

* Endurance reliability

The prepared polarizer-adhered sheet was cut so as to have a size of 300 mm x 220 mm, and then it was bonded to a glass of Corning # 1737 to prepare a specimen. The prepared specimens were treated in an autoclave at 5 atm and 50 ° C for 20 minutes and then placed in an oven at 60 ° C and 90% relative humidity for 300 hours. The peeling phenomenon such as peeling and exfoliation of the specimen left on the surface of the specimen and the occurrence of bubbles were visually confirmed and evaluated based on the following criteria.

○: No peeling and no bubbles (Good)

△: Peeling phenomenon and generation of bubbles are somewhat (usually)

X: Peeling phenomenon and occurrence of air bubbles (defective)

* Light leakage (light leakage test)

 The prepared polarizing plate adhesive sheet was cut into a size of 200 mm x 200 mm, and the sample was attached to both sides of the glass substrate (210 mm x 210 mm x 0.7 mm) so that the optical absorption axis crossed 90 degrees. The prepared specimens were treated in an autoclave at 5 atm and 50 ° C for 20 minutes and then placed in an oven at 60 ° C and 90% relative humidity for 300 hours. The sample was visually observed for light leakage from specimens left in the dark room, and evaluated according to the following criteria.

○: It is difficult to visually judge the non-uniformity of light gaps

△: Light scattering is somewhat uneven

X: There is a non-uniformity of light leakage

* Adhesion

The sample was cut from the prepared polarizing plate adhesive sheet (pressure-sensitive adhesive layer thickness: 25 mu m) such that the width was 25 mm and the length was 150 mm. The release sheet (release film) of the cut sample was peeled off, laminated on a glass of Corning # 1737, and then pressurized in an autoclave under the conditions of 0.5 MPa and 50 캜 for 20 minutes and left under the environment of 23 캜 and 50% relative humidity for 24 hours Respectively. The adhesive force was measured using a tensile tester (AUTOGRAPH AG-IS 50N, manufactured by Shimadzu Corp.) under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 °.

* Measurement of storage modulus (G ')

The polarizing plate adhesive sheet (thickness of the pressure-sensitive adhesive layer: 25 mu m) was measured using a torsional shear method after preparing a cylindrical test piece having a diameter of 25 mm and a thickness of 1 mm.

Measuring instrument: Dynamic viscoelasticity measuring device (MCR300, PSICA)

Frequency: 1 Hz

Measuring temperature: 23 ° C

division Surface resistivity
(Ω / □) adhesiveness
(N / 25 mm) Storage modulus
(MPa) Endurance reliability Light beam Example 1 3.1 × 10 ¹¹ 2.5 1.22 ○ ○ Example 2 1.9 × 10 ¹¹ 2.1 1.63 ○ ○ Example 3 2.7 × 10 ¹¹ 1.1 6.43 △ ○ Example 4 2.4 × 10 ¹¹ 3.8 0.67 ○ ○ Example 5 3.2 × 10 ¹¹ 3.9 0.79 ○ ○ Example 6 3.4 × 10 ¹¹ 1.7 4.12 △ ○ Example 7 9.3 × 10 ¹¹ 2.1 1.21 ○ ○ Example 8 4.7 × 10 ¹¹ 1.9 1.34 ○ ○ Example 9 2.5 × 10 ¹⁰ 2.9 1.32 ○ ○ Example 10 4.4 × 10 ⁹ 2.7 1.19 ○ ○ Example 11 1.6 × 10 ⁹ 2.4 1.41 ○ ○ Comparative Example 1 3.3 × 10 ¹¹ 26.2 0.25 ○ × Comparative Example 2 5.4 × 10 ¹¹ 18.7 0.36 ○ × Comparative Example 3 4.1 × 10 ¹¹ 2.4 1.11 × ○ Comparative Example 4 5.3 × 10 ¹² 2.3 1.21 △ ○ Comparative Example 5 4.3 × 10 ¹² 3.1 1.23 ○ ○

As shown in Table 2, the polarizing plate adhesive sheets of Examples 1 to 11 including the ultraviolet curable compound and the antistatic agent represented by the formula (1) according to the present invention are excellent in endurance reliability and antistatic property, The storage elastic modulus (G ') indicates that the re-peeling property is excellent and the light leakage phenomenon can be improved. In particular, Examples 9 to 11, in which 1.0 to 5.0 parts by weight of the antistatic agent were contained, were preferable because of better durability, antistatic property and re-releasability.

On the other hand, Comparative Examples 1 and 2, which did not contain ultraviolet curable compounds, exhibited a high adhesive strength and a low storage modulus, resulting in poor re-releasability and light leakage. In addition, Comparative Examples 3 to 5 containing an antistatic agent not falling within the scope of the present invention had poor endurance reliability or antistatic property.

Claims (9)

A pressure-sensitive adhesive composition comprising an acrylic copolymer, an ultraviolet curable compound, a photopolymerization initiator, a crosslinking agent, and an antistatic agent represented by the following formula (1): [Chemical Formula 1] M ⁺ [(FSO ₂ ) ₂ N] ^- Wherein M is an alkali metal. The pressure-sensitive adhesive composition according to claim 1, wherein the ultraviolet curable compound is at least one selected from the group consisting of a polyfunctional (meth) acrylate monomer having a weight average molecular weight of less than 1,000 and a (meth) acrylate oligomer having a weight average molecular weight of 50,000 or less . The polyfunctional (meth) acrylate monomer according to claim 2, wherein the polyfunctional (meth) acrylate monomer is 1,4-butanediol di (meth) acrylate, 1,6- hexanediol di (meth) acrylate, neopentyl glycol di (Meth) acrylate, ethylene glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl (meth) acrylate, ethylene oxide modified di ) Isocyanurate, allyl cyclohexyl di (meth) acrylate, dimethylol dicyclopentane diacrylate, ethylene oxide modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol acrylate, neopentyl glycol modified trimethylol propane (Meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tri (Meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylol propane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, di (Meth) acrylate selected from the group consisting of glycerin tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, propionic acid modified dipentaerythritol penta (meth) acrylate and caprolactone modified dipentaerythritol hexa Or more. The pressure-sensitive adhesive composition according to claim 1, wherein the weight ratio of the acrylic copolymer to the ultraviolet curable compound is 100: 5 to 100: 50. The pressure-sensitive adhesive composition according to claim 1, wherein the alkali metal is potassium. The pressure-sensitive adhesive composition according to claim 1, wherein the antistatic agent is contained in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the acrylic copolymer (based on the solid content). The pressure-sensitive adhesive composition according to claim 1, wherein the pressure-sensitive adhesive layer composed of the pressure-sensitive adhesive composition has a storage elastic modulus (G ') of from 0.5 to 10 MPa at 23 ° C. A polarizing plate laminated with a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition according to any one of claims 1 to 7. A liquid crystal display device comprising the liquid crystal cell according to claim 8 on at least one surface thereof.