KR20090100101A - Antistatic pressure sensitive adhesive composition, polaring plate and liquid crystal display device using the same - Google Patents

Abstract

PURPOSE: An antistatic pressure sensitive adhesive composition is provided to improve antistatic property while maintaining durability of an adhesive itself. CONSTITUTION: An antistatic pressure sensitive adhesive composition comprises alkyl (meth)acrylate copolymer, antistatic agent, epoxy-based cross-linking agent and polyalkyleneglycol-based silane coupling agent. The content of the polyalkyleneglycol-based silane coupling agent is 0.005 ~ 1.2 parts by weight based on 100 parts by weight of alkyl (meth)acrylate copolymer. The alkyl (meth)acrylate copolymer is a copolymer of alkyl (meth)acrylate monomer and polymerizable monomer.

Description

Antistatic adhesive composition, polarizing plate and liquid crystal display device using the same {ANTISTATIC PRESSURE SENSITIVE ADHESIVE COMPOSITION, POLARING PLATE AND LIQUID CRYSTAL DISPLAY DEVICE USING THE SAME}

The present invention relates to an antistatic adhesive composition, a polarizing plate and a liquid crystal display device using the same, which can greatly improve antistatic properties while maintaining durability of the adhesive itself.

In general, in order to manufacture a liquid crystal display device (LCD), a liquid crystal cell and a polarizing plate including a liquid crystal are basically required, 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, and the polyvinyl alcohol (PVA) polarizing film (or 'polarizer') and the iodine-based compound or dichroic polarizing material adsorbed and oriented to protect both sides of the polarizing film It includes a polarizer protective film laminated in order to. Specifically, a triacetyl cellulose (TAC) based protective film is laminated on one side of the polarizing film, and an antistatic layer, an antireflection layer, a hard coating layer, etc. are laminated on the protective film, and the other side of the polarizing film On one side, a protective film made of a polymer of a triacetyl cellulose film or a cyclic olefin is laminated, and is composed of a multilayer in which an adhesive layer and a release film are laminated on the protective film.

In the process of attaching the polarizing plate to the liquid crystal cell in the manufacturing of the liquid crystal display device, peeling the release film from the pressure-sensitive adhesive layer generates static electricity. The generated static electricity affects the alignment of the liquid crystal inside the liquid crystal display device, causing defects. In addition, electrostatic attraction causes contamination by foreign substances between the liquid crystal cell and the adhesive. Recently, due to the expansion of the market for slim wall-mounted TVs, polarizing plates of liquid crystal display panels have also been enlarged, and thus electrostatic problems have become more important.

In order to solve the problems caused by static electricity generation, a method of imparting antistatic property to a polarizing plate includes a method of using a conductive adhesive with a conductive material added on a protective film, and an antistatic layer by applying a conductive material between the polarizing plate and the adhesive layer. A method of forming a resin or a method of using a conductive adhesive containing an ionic acrylate copolymer as an adhesive resin has been proposed.

The method for imparting antistatic property to the above-mentioned polarizing plate is described in detail as follows.

First, a method of using a conductive adhesive with a conductive substance added on a protective film will be described in detail. A method of adding a conductive component such as a conductive polymer, metal oxide particles, and carbon particles to the adhesive, metal salts and organic salts. Or a method of adding an ionic material such as a surfactant (Korean Patent Publication No. 1998-0081608, Korean Patent Publication No. 1989-0013673, Korean Patent Publication No. 2001-0111715, Korean Patent Publication No. 2004-0032058, Korean Laid-Open Patent No. 2006-0018495, Korean Laid-open Patent No. 2004-0030919, Korean Laid-Open Patent 2001-0010433, Korean Laid-Open Patent No. 2005-0072567, Japanese Laid-Open Patent No. 2006-111856, Japanese Patent Laid-Open No. 2006-111846, Japanese Patent Laid-Open No. 2006-104434). However, the conductive material as described above should be added in a large amount in order to impart antistatic properties, which may lower the transparency of the pressure-sensitive adhesive layer, and the surfactant is susceptible to humidity and transfers to the pressure-sensitive adhesive surface, thereby lowering the adhesive properties. There is a drawback to this.

In addition, in addition to the above components, there is a method of suppressing the generation of static electricity by adding ethylene oxide modified dioctyl phthalate plasticizer to the pressure-sensitive adhesive, but the addition of the plasticizer is not only difficult to suppress the static electricity generated initially. It is also difficult to dissipate the static electricity remaining after peeling off the release film (Japanese Patent Laid-Open Publication No. 199-140519).

Next, a method of forming an antistatic layer by applying a conductive material between the polarizing plate and the pressure-sensitive adhesive layer will be described in detail. A method of depositing an electrically conductive metal powder or a metal oxide, or a method of coating a conductive polymer, etc. Is being performed. However, this method requires a process of stacking an antistatic layer in order to impart an antistatic performance to a polarizing plate having a multi-layered structure, which causes a complicated process and leads to an increase in unit cost (Korean Patent Publication No. 1997-7002906). , Korean Patent Publication No. 2005-0036310, Japanese Patent Publication No. 2006-095875, Japanese Patent Publication No. 2006-095874, Japanese Patent Publication No. 2006-076251, Japanese Patent Publication No. 2005-271573, Japanese Patent Publication No. 2005-238651, Japanese Laid-Open Patent No. 2005-200607, Japanese Laid-Open Patent No. 1999-091038, Japanese Laid-Open Patent No. 194-220408, Japanese Laid-Open Patent No. 1998-114886).

Finally, a method of using a conductive adhesive containing an ionic acrylate copolymer as the adhesive resin is a method for preventing the conductive material from bleeding out from the pressure-sensitive adhesive, which requires no additional coating process. The method has been proposed. Specifically, Korean Patent Publication No. 2001-0111715 (published Dec. 20, 2001) includes a method of preparing a polymer containing an epoxy group and introducing a quaternary ammonium salt by adding a tertiary amine to an epoxy group, and tertiary amine. A method of preparing a polymer and reacting dimethyl sulfate with a tertiary amine to introduce a quaternary ammonium salt is disclosed.

Such conventional methods have been able to solve the static problem. However, as the polarizing plate of the liquid crystal display panel is enlarged due to the expansion of the market for a slim large wall-mounted TV, the electrostatic problem becomes more important, and thus an adhesive composition having improved antistatic properties is required.

According to the present invention, the antistatic property is greatly improved without causing a problem of durability caused by adding a large amount of antistatic agent to the pressure-sensitive adhesive composition in order to exhibit the high antistatic property required for the polarizing plate when applied to large liquid crystal display devices. It is an object to provide an antistatic adhesive composition.

Another object of the present invention is to provide a polarizing plate and a liquid crystal display using the pressure-sensitive adhesive composition.

In order to achieve the above object, the present invention is an adhesive composition comprising an alkyl (meth) acrylate copolymer, an antistatic agent, a crosslinking agent, an epoxy silane coupling agent and a polyalkylene glycol-based silane coupling agent, wherein the polyalkylene The glycol-based silane coupling agent provides an antistatic adhesive composition containing 0.005 to 1.2 parts by weight based on 100 parts by weight of the alkyl (meth) acrylate-based copolymer.

In another aspect, the present invention provides a polarizing plate in which the pressure-sensitive adhesive layer made of the antistatic adhesive composition is laminated, and the liquid crystal display device having the polarizing plate.

According to the present invention, the antistatic property can be greatly improved as compared with the conventional antistatic pressure-sensitive adhesive composition by synergistic effect of a small amount of polyalkylene glycol-based silane coupling agent and the antistatic agent while maintaining the existing physical properties of the pressure-sensitive adhesive itself. .

The present invention relates to an antistatic adhesive composition, a polarizing plate and a liquid crystal display device using the same, which can greatly improve antistatic properties while maintaining durability of the adhesive itself.

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

The antistatic adhesive composition of the present invention is an adhesive composition comprising an alkyl (meth) acrylate copolymer, an antistatic agent, a crosslinking agent, an epoxy silane coupling agent, and a polyalkylene glycol-based silane coupling agent, and in particular, the polyalkylene It is characterized in that the glycol-based silane coupling agent is included in 0.005 to 1.2 parts by weight based on 100 parts by weight of the alkyl (meth) acrylate copolymer.

Alkyl (meth) acrylate type copolymer is an alkyl (meth) acrylate type copolymer which has a crosslinkable functional group in a side chain, For example, the alkyl (meth) acrylate monomer which has 4-12 carbon atoms of an alkyl group, bridge | crosslinking to a side chain The copolymer of the polymerizable monomer which has a possible functional group, and the monomer copolymerizable as needed can be used. In this case, (meth) acrylate means that includes both acrylate and methacrylate.

Examples of the alkyl (meth) acrylate having 4 to 12 carbon atoms include (meth) acrylates derived from aliphatic alcohols having 4 to 12 carbon atoms. Specific examples include n-butyl (meth) acrylate, 2-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth ) Acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, etc. are mentioned, These can be used individually or in combination of 2 or more types. Among them, n-butyl acrylate, 2-ethylhexyl acrylate or a mixture thereof can be preferably used.

Examples of the polymerizable monomer having a crosslinkable functional group in the side chain include a polymerizable monomer having a carboxyl group, a hydroxyl group, an amide group or a tertiary amine group.

Specific examples of the polymerizable monomer having a carboxyl group include monovalent acids such as (meth) acrylic acid and crotonic acid; Diacids such as maleic acid, itaconic acid and fumaric acid, and monoalkyl esters thereof; 3- (meth) acryloylpropionic acid; 2-hydroxyalkyl (meth) acrylate having 2 to 3 carbon atoms in the alkyl group, polyoxyalkylene glycol mono (meth) acrylate having 2 to 4 carbon atoms in the alkyl group, and (meth) having 2 to 3 carbon atoms in the alkyl group The compound etc. which ring-opened and added amber acid anhydride to the caprolactone adduct to acrylate are mentioned.

Specific examples of the polymerizable monomer having a hydroxy group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and an alkyl group having 2 carbon atoms. Polyoxyalkylene glycol mono (meth) acrylate etc. which are -4 are mentioned.

(Meth) acrylamide is mentioned as a polymerizable monomer which has the said amide group, As a monomer which has the said tertiary amine group, N, N- dimethylamine ethyl (meth) acrylate can be used.

Specific examples of the copolymer of the monomer copolymerizable as necessary include alcohols having 1 to 3 carbon atoms of alkyl groups such as methyl (meth) acrylate, ethyl (meth) acrylate, and isopropyl (meth) acrylate ( Meta) acrylic acid ester; (Meth) acrylic acid esters of alcohols having 13 to 18 carbon atoms of alkyl groups such as tridecyl (meth) acrylate and stearyl (meth) acrylate; (Meth) acrylic acid ester of cyclic alcohols, such as cyclohexyl (meth) acrylate; (Meth) acrylates of aromatic alcohols such as benzyl (meth) acrylate; Aromatic monomers such as styrene and vinyltoluene; Allyl compounds such as allyl acetate; Monomers having nitrile groups such as (meth) acrylonitrile and α-chloro (meth) acrylonitrile; Halogen-containing monomers such as vinyl chloride and vinylidene chloride; Vinyl ester monomers such as vinyl acetate, vinyl propionate and vinyl butyrate; Or vinyl ether monomers such as vinyl ethyl ether, vinyl propyl ether, vinyl isobutyl ether, and the like, and methyl (meth) acrylate is preferable.

The weight ratio of the alkyl (meth) acrylate monomer having 4 to 12 carbon atoms of the alkyl group, the polymerizable monomer having a crosslinkable functional group in the side chain, and the copolymerizable monomer as necessary is usually (80 to 99.0): (1.0 to 20): (0-10), Preferably it is (90-99.9): (1.0-10): (0-5). When the weight ratio of the alkyl (meth) acrylate having 4 to 12 carbon atoms corresponding to the main chain in the alkyl (meth) acrylate-based copolymer is less than 80, the adhesive force is insufficient, and when it exceeds 99.0, the cohesive force is lowered. Cohesion force falls when the weight ratio of the polymerizable monomer which has a crosslinkable functional group in a side chain is less than 1.0, and when it exceeds 20, adhesive force falls. Moreover, when the weight ratio of the copolymerizable monomer exceeds 10 as needed, adhesive force falls.

The alkyl (meth) acrylate copolymer having a crosslinkable functional group in the side chain may be prepared using a known polymerization method, for example, bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, and the like, and preferably It is using a polymerization method. In the polymerization, azo-based polymerization initiators such as azobisisobutyronitrile and azobisisovaleronitrile, and peroxide-based polymerization initiators such as benzoyl peroxide, di-t-butyl peroxide, and lauryl peroxide may be used. Known polymerization initiators and known chain transfer agents such as mercapto group-containing chain transfer agents can be used.

The alkyl (meth) acrylate-based copolymer having a crosslinkable functional group in the side chain has a weight average molecular weight (polystyrene equivalent) measured by gel permeation chromatography (GPC) method is usually 50,000 to 2,000,000, preferably Is 100,000 to 1,800,000, more preferably 500,000 to 1,500,000.

Epoxy-based silane coupling agent is generally used to improve the adhesion between the glass substrate and the pressure-sensitive adhesive or the adhesive strength and the heat-resistant heat resistance in the pressure-sensitive adhesive for a liquid crystal display device, it is more preferably used when considering only the moisture and heat resistance.

The epoxy group in the silane coupling agent molecule binds to the reactive functional group of the alkyl (meth) acrylate copolymer, and the alkoxysilane moiety strongly bonds to the glass substrate of the liquid crystal cell, which is the substrate to which the adhesive is applied, thereby connecting the adhesive to the substrate. It improves the adhesion stability and further improves the heat and moisture resistance, and especially helps to improve the adhesion reliability when left for a long time under high temperature and high humidity.

Specific examples include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-glycidoxyethyltrimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimeth And oxysilanes. These may be used alone or in combination of two or more thereof.

It is preferable that the said epoxy silane coupling agent is contained in 0.01-5.0 weight part with respect to 100 weight part of alkyl (meth) acrylate type copolymers. In the content range, it improves the adhesion stability of the pressure-sensitive adhesive composition and further improves the heat and moisture resistance, and in particular, serves to improve the adhesion reliability when left for a long time under high temperature and high humidity.

In the present invention, a polyalkylene glycol-based silane coupling agent is used together with the epoxy silane coupling agent to further improve the antistatic property.

The polyalkylene glycol-based silane coupling agent is a silane coupling agent containing an alkylene glycol group capable of reacting with a glass substrate, such as methoxysilane, ethoxysilane, methyldimethoxysilane, methyldiethoxysilane, and the like. The terminal part of a glycol group is a hydroxyl group itself, and the thing substituted by the alkyl group or the phenyl group can also be used. Specific examples thereof include one or more selected from polyethylene glycol propyl trimethoxy silane, polypropylene glycol propyl trimethoxy silane, and the like.

Conventionally, alkylene glycol groups have been introduced and used in alkyl (meth) acrylate copolymers in order to improve antistatic properties. In this case, when included in less than 10 parts by weight with respect to 100 parts by weight of the copolymer there is a disadvantage that there is almost no antistatic effect to add a large amount. On the other hand, in the present invention, by using the silane coupling agent containing an alkylene glycol group, it was possible to obtain a high antistatic property which can not be obtained by the antistatic agent alone even with a small amount of addition. Moreover, since it is used as a silane coupling agent which can be said to be an essential component in the optical film adhesive composition for organic substrate lamination | stacking, it is more preferable at the point which is excellent in compatibility, and can maintain the physical property of an adhesive composition.

The polyalkylene glycol-based silane coupling agent is preferably included in an amount of 0.005 to 1.2 parts by weight, more preferably 0.01 to 1.0 part by weight based on 100 parts by weight of the alkyl (meth) acrylate-based copolymer. If the content is less than 0.005 parts by weight, the effect of improving the antistatic property is insignificant, and if the content exceeds 1.2 parts by weight, it is difficult to secure durability.

It is preferable to use ionic compounds, such as an alkali metal salt and a quaternary ammonium salt, as an antistatic agent.

As the alkali metal salt is effected by the ion combination of positive and negative ions, for example, of one member selected from lithium, sodium, potassium, magnesium, calcium, and the group consisting of barium and cesium cations, Cl ^-, Br ^-, I ^{- _{, AlCl 4 -, Al 2 Cl}} 7 -, BF 4 -, PF 6 -, ClO 4 -, NO 3 -, CH 3 COO -, CF 3 COO -, CH 3 SO 3 -, CF 3 SO 3 -, ( ^{_{CF 3 SO 2) 2 N -}} , (CF 3 SO 2) 3 C -, AsF 6 -, SbF 6 -, NbF 6 -, TaF 6 -, F (HF) n -, (CN) 2 N -, C ^{_{4 F 9 SO 3 -, (}} C 2 F 5 SO 2) 2 N -, C 3 F 7 COO - , and _{(CF 3 SO 2) (CF} 3 CO) N - ion of the anion of one member selected from the group consisting of The alkali metal salt formed by the combination is mentioned, These can be used individually or in combination of 2 or more types.

The quaternary ammonium salts are formed by ion combination of cations and anions, and among them, quaternary ammonium salts containing a weakly coordinated anion are preferable. For example, a cation selected from the group consisting of tetramethylammonium, tetraethylammonium, tetrabutylammonium and tetrahexyl ammonium, perchlorate, tetrafluoroborate, hexafluorophosphate, benzoate, trifluoromethanesulfonate, Quaternary ammonium salts formed by ion combinations of one anion selected from the group consisting of tetraphenylborate, p-toluenesulfonate, chloride, fluoride, bromide, iodide, carbonate and acetate; It can be used individually or in combination of 2 or more types.

In addition to the alkali metal salts and quaternary ammonium salts, ionic compounds formed by ion combinations of cations and anions may also be used. In this case, the cation may be a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a cation having a pyrroline skeleton, a cation having a pyrrole skeleton, an imidazolium cation, a tetrahydropyrimidinium cation, a dihydropyrimidinium cation. And tetraalkylammonium cations, trialkylsulfonium cations, tetraalkylphosphonium cations and cations in which some of these alkyl groups are substituted with alkenyl groups, alkoxyl groups or epoxy groups. Anion as is if it is satisfied for a possible ionic compound that kind is not particularly limited, and specific examples are ^{Cl -, Br -, I -} , AlCl 4 -, Al 2 Cl 7 -, BF 4 -, PF 6 -, _{^{ClO 4 -, NO 3 -,}} CH 3 COO -, CF 3 COO -, CH 3 SO 3 -, CF 3 SO 3 -, (CF 3 SO 2) 2 N -, (CF 3 SO 2) 3 C -, _{^{AsF 6 -, SbF 6 -,}} NbF 6 -, TaF 6 -, F (HF) n -, (CN) 2 N -, C 4 F 9 SO 3 -, (C 2 F 5 SO 2) 2 N -, C ₃ F ₇ COO ^- or (CF ₃ SO ₂ ) (CF ₃ CO) N ^- and the like.

The antistatic agent is preferably included in 0.05 to 5.0 parts by weight based on 100 parts by weight of the alkyl (meth) acrylate copolymer. More preferably, it is 0.1-2.0 weight part. Especially preferably, it is 0.1-1.0 weight part. In the above content range, antistatic properties are improved by use with a polyalkylene glycol-based silane coupling agent, and the durability of the pressure-sensitive adhesive composition is practically not impaired.

A crosslinking agent is used in order to strengthen the cohesion force of an adhesive, A well-known crosslinking agent can be used. For example, Melamine derivatives, such as hexamethylol melamine, hexamethoxymethyl melamine, and hexabutoxymethyl melamine; Diisocyanate compounds such as tolylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, 2,4-diphenylmethane diisocyanate, 4,4-diphenylmethane diisocyanate, and trimethyrol propane of diisocyanate Polyisocyanate compounds such as adducts to polyhydric alcohol compounds; Polyepoxy compounds such as an epoxy compound of bisphenol A epichlorohydrin condensate type, polyglycidyl ether of polyoxyalkylene polyol, glycerin diglycidyl ether, glycerin triglycidyl ether, and tetraglycidyl xylenediamine; Or an aziridine-based compound such as trimethylolpropane tri-β-aziridinylpropionate, and the like, and preferably a polyisocyanate compound or a polyepoxy compound can be used. These can be used individually or in combination of 2 or more types.

The crosslinking agent is preferably included in 0.1 to 5 parts by weight based on 100 parts by weight of the alkyl (meth) acrylate copolymer. When the content is less than 0.1 parts by weight, the cohesion force becomes small due to insufficient crosslinking degree, thereby impairing the adhesive durability and the cutting property, and when the content exceeds 5 parts by weight, there is a problem in reducing residual stress due to excessive crosslinking reaction.

The antistatic pressure-sensitive adhesive composition comprising the above components may further include a known gun gun additive in a range that does not reduce the adhesive properties, optical properties and antistatic properties, such as durability, re-peelability, and the like. As an example of an additive, tackifying resin, a plasticizer, an ultraviolet inhibitor, a mildew agent, an antifoamer, etc. are mentioned.

As the tackifying resin, rosin, rosin derivative or a hydrogenated body thereof, polyterpene resin, terpene phenol resin, xylene resin, styrene resin, coumarone-indene resin, C5 petroleum resin, C9 petroleum resin and the like can be used. As the plasticizer, carboxylic acid esters represented by phthalic acid esters, paraffin chloride and the like can be used. A benzophenone type compound etc. can be used as said ultraviolet-ray inhibitor, copper nitrous oxide, a phenol type compound, etc. can be used, An alcohol, a silicone compound, etc. can be used as an antifoamer.

The antistatic adhesive composition may be formed as an adhesive layer by a direct coating method or a transfer method commonly used in the art. In the case of the direct coating method, a film made of a polymer of triacetyl cellulose or a cyclic olefin, which is used as a protective film of the polarizing plate, is used as a base material, and the pressure-sensitive adhesive composition is flow casted by using a common coating apparatus on the base material, and air. The pressure-sensitive adhesive layer can be formed by directly applying and drying by an air knife, gravure, reverse roll, kiss roll, spray or blade method. In the transfer method, silicone or fluorinated release film on a film or resin plate of various plastics such as polyethylene, polypropylene, polyethylene terephthalate, soft polyvinyl chloride or the like, preferably silicone release on polyethylene terephthalate By using the obtained film as a base material, and applying and drying in the same coating method as described above can form an adhesive layer, it can be transferred to the polarizing plate protective film using a roll pressing device.

In this case, when the adhesive composition is applied and dried for curing for as long as necessary, for example, about 7 days, the adhesive layer is completely cured by the crosslinking reaction of the crosslinking agent and the alkyl (meth) acrylate copolymer. Characteristics. Curing may be carried out, for example, usually at room temperature for 3 to 7 days, or may be carried out at more severe temperature conditions in order to shorten the curing time.

The adhesive layer which consists of an antistatic adhesive composition of this invention is not only an adhesive for polarizing plates but a tape for electrical / electronic component processing, such as a dicing tape and a carrier tape; Surface protection tapes such as stainless steel sheet and plastic sheet; Or adhesives such as sheets, mats, adhesive labels, stickers, tapes, and the like.

The present invention provides a polarizing plate in which an adhesive layer made of an antistatic adhesive composition is laminated.

The polarizing plate comprises a polarizing film and a protective film provided on both sides of the polarizing film, characterized in that the pressure-sensitive adhesive layer made of an antistatic pressure-sensitive adhesive composition according to the present invention on at least one of the protective films. do.

In another aspect, the present invention provides a liquid crystal display device comprising a polarizing plate laminated with an adhesive layer made of the antistatic adhesive composition.

In the present invention, since the polarizing plate and the liquid crystal display device are well known to those skilled in the art, detailed descriptions of the respective components except for the adhesive layer made of the antistatic adhesive composition will be omitted.

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

Preparation Example 1 Preparation of Alkyl (meth) acrylate-Based Copolymer Having Crosslinkable Functional Group in the Side Chain

A 4-neck jacketed reactor (1L) was equipped with a stirrer, a thermometer, a reflux condenser, a dropping lot and a nitrogen gas inlet tube, 164 parts of ethyl acetate, 126 parts of n-butyl acrylate, 0.5 parts of acrylic acid, 2 1.3 parts of hydroxyethyl acrylate were added thereto, and the temperature of the reactor was raised to 50 ° C. 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 further stirring for 6 hours at the same temperature, 304 parts of ethyl acetate was added, followed by stirring for 2 hours to obtain a final alkyl (meth) acrylate copolymer.

The prepared alkyl (meth) acrylate copolymer was a copolymer having a lactic acid group in the side chain, the solid content was 20%, and the weight average molecular weight (polystyrene conversion) by the GPC method was about 1,500,000.

Example 1

To 100 parts of the copolymer prepared in Preparation Example 1 (based on the solids content), 0.6 parts of CORONATE-L (TDI ADDUCT manufactured by Polyurethane), a polyisocyanate-based crosslinking agent, 3-glycidoxypropyltrimethoxy as an epoxy silane coupling agent 0.15 parts of silane [Shin-Etsu Co., Ltd. KBM-403], 0.01 parts of polyethylene glycol propyl silane [Shin-Etsu Co., X-12-641] as a polyalkylene glycol-based silane coupling agent, and 0.3 parts of lithium iodide (LiI) as an antistatic agent The adhesive composition was prepared by adding and stirring for 20 minutes.

The prepared pressure-sensitive adhesive composition was applied on a polyethylene terephthalate film (41 cm x 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. Another layer of the release film was laminated thereon and cured at 23 ° C. for 7 days to prepare an adhesive sheet. The release film of one side of the prepared pressure-sensitive adhesive sheet was removed, and laminated on both sides of the polyvinyl alcohol polarizing film to a polarizing plate having a triacetyl cellulose protective film to be laminated to prepare a polarizing plate having an antistatic pressure-sensitive adhesive layer laminated thereon.

Example 2

The same method as Example 1 except that 0.6 parts of CORONATE-HX (Japan Polyurethane TDI trimer) was used as a crosslinking agent and 0.05 parts of polyethylene glycol propyl silane [Shin-Etsu Co., Ltd. X-12-641] was used. Was carried out.

Example 3

The same method as in Example 1, except that D140N (Mitsui Chemical Co., Ltd. IPDI-ADDUCT) was used as a crosslinking agent in 0.6 parts and 0.1 parts of polyethylene glycol propyl silane [Shin-Etsu Co., Ltd. X-12-641] was used. Was carried out.

Example 4

The same procedure as in Example 1 was carried out except that 0.5 parts of polyethylene glycol propyl silane [Shin-Etsu Co., Ltd. X-12-641] was used.

Example 5

The same procedure as in Example 1 was carried out except that 1.0 part of polyethylene glycol propyl silane [Shin-Etsu Co., Ltd. X-12-641] was used.

Example 6

Except for using a polyethylene glycol propyl trimethoxysilane [Shin-Etsu Corporation X-12-641] 0.1 parts, and using an antistatic agent of 0.5 parts of LiClO ₄ was carried out as Example 1.

Example  7

Example 1 except that polyethylene glycol propyl silane [Shin-Etsu Co., Ltd. X-12-641] was used in 0.1 part, and the antistatic agent IL-P14-2 (1-methyl-4-hexylpyridinium hexafluorophosphate) was used in 0.8 part. It carried out by the same method as 1.

Comparative Example 1

The same procedure as in Example 1 was carried out except that polyethylene glycol propyl methoxysilane [Shin-Etsu Co., Ltd. X-12-641] was not used.

Comparative example  2

Example 1 except that 3-glycidoxypropyltrimethoxysilane [Shin-Etsu Co., Ltd. KBM-403] was not used and 0.1 part of polyethylene glycol propyl silane [Shin-Etsu Co., X-12-641] was used. It carried out in the same way.

Comparative example  3

Except that 3-glycidoxypropyltrimethoxysilane [Shin-Etsu Co., Ltd. KBM-403] and lithium iodide were not used, and polyethyleneglycolpropylmethoxysilane [Shin-Etsu Co., Ltd. X-12-641] was used in 0.5 part. It carried out in the same manner as in Example 1.

Comparative Example 4

The same procedure as in Example 1 was conducted except that 1.5 parts of polyethylene glycol propyl silane (Shin-Etsu Co., Ltd. X-12-641) was used.

Comparative Example 5

Polyethylene glycol propyl trimethoxysilane using the polyalkylene glycol additives of polypropylene glycol 2000 in place without the use of [Shin-Etsu Corporation X-12-641], and 5.0 parts, except for using an antistatic agent in LiClO ₄ 0.5 parts It carried out in the same manner as in Example 1.

The components of the antistatic adhesive composition prepared in Examples and Comparative Examples and their compositions are shown in Table 1 below.

division Copolymer Crosslinking agent Epoxy-based silane coupling agent Polyalkylene glycol-based silane coupling agent Polyalkylene glycol Antistatic agent COR-L CO-HX D140N KBM-403 X-12-641 PPG 2000 LiI LiClO ₄ IL-P14-2 Example 1 100 0.6 - - 0.15 0.01 - 0.3 - - Example 2 100 - 0.6 - 0.15 0.05 - 0.3 - - Example 3 100 - - 0.6 0.15 0.1 - 0.3 - - Example 4 100 0.6 - - 0.15 0.5 - 0.3 - - Example 5 100 0.6 - - 0.15 One - 0.3 - - Example 6 100 0.6 - - 0.15 0.1 - - 0.5 - Example 7 100 0.6 - - 0.15 0.1 - - - 0.8 Comparative Example 1 100 0.6 - - 0.15 - - 0.3 - - Comparative Example 2 100 0.6 - - - 0.1 - 0.3 - - Comparative Example 3 100 0.6 - - - 0.5 - - - - Comparative Example 4 100 0.6 - - 0.15 1.5 - 0.3 - - Comparative Example 5 100 0.6 - - 0.15 - 5.0 - 0.5 -

In Table 1, each component is as follows.

* COR-L: CORONATE-L Japan Polyurethane Industry TDI-ADDUCT

* CO-HX: CORONATE-HX Japan Polyurethane Industry TDI trimer

* D140N: Mitsui Chemicals Polyurethane Industry IPDI-ADDUCT

* KBM-403: 3-glycidoxypropyltrimethoxysilane [Shin-Etsu Corp.]

* X-12-641: Polyethyleneglycolpropyltrimethoxysilane (Shin-Etsu Co., Ltd.)

* PPG2000: Polypropylene glycol (Aldrich Molecular Weight 2000)

LiI: Lithium iodide

* LiClO ₄ : Lithium perchlorate

* IL-P14-2: 4-Hexyl-1-methylpyridinium hexafluorophosphate

Test Example

After removing the release film of the polarizing plate in which the pressure-sensitive adhesive layer made of the antistatic pressure-sensitive adhesive composition prepared in Examples and Comparative Examples was removed, the physical properties were measured by the following method, and the results are shown in Table 2 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: Three points on the surface were measured 10 times each and expressed as the average value.

* durability

After cutting the polarizing plate on which the pressure-sensitive adhesive layer is laminated to 15 inches and then bonded to Corning # 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 phenomenon such as lifting and peeling of the specimen left undisturbed and bubbles were observed visually, and evaluated based on the following criteria.

○: No peeling phenomenon or bubbles (good)

△: peeling phenomenon and bubbles are somewhat generated

X: Peeling phenomenon and bubbles are generated (defect)

division Example Comparative example One 2 3 4 5 6 7 One 2 3 4 5 Surface resistivity (Ω / □) 9.80 E + 10 7.70 E + 10 6.50 E + 10 4.30 E + 10 5.50 E + 9 3.50 E + 10 3.50 E + 10 3.73 E + 11 5.70 E + 10 1.20 E + 13 1.20 E + 9 5.73 E + 11 durability ○ ○ ○ ○ △ ○ ○ ○ X X X △

As shown in Table 2, according to the present invention, the polyalkylene glycol-based silane coupling agent together with the epoxy-based silane coupling agent in an amount of 0.005 to 1.2 parts by weight based on 100 parts by weight of the alkyl (meth) acrylate copolymer It was confirmed that the antistatic pressure-sensitive adhesive composition of Examples 1 to 7 significantly improved the antistatic property while maintaining the adhesion durability compared to Comparative Example 1 containing only the epoxy-based silane coupling agent.

In addition, Comparative Examples 2 to 3, which do not contain an epoxy silane coupling agent, and Comparative Example 4, which contains an excessive amount of a polyalkylene glycol-based silane coupling agent, did not achieve durability and antistatic properties. In Comparative Example 5 including the additive, the antistatic property was greatly reduced.

Claims (8)

An adhesive composition comprising an alkyl (meth) acrylate copolymer, an antistatic agent, a crosslinking agent, an epoxy silane coupling agent, and a polyalkylene glycol-based silane coupling agent, wherein the polyalkylene glycol-based silane coupling agent is an alkyl (meth) Antistatic pressure-sensitive adhesive composition containing 0.005 to 1.2 parts by weight based on 100 parts by weight of the acrylate copolymer. The antistatic adhesive according to claim 1, wherein the alkyl (meth) acrylate copolymer is a copolymer of an alkyl (meth) acrylate monomer having 4 to 12 carbon atoms in the alkyl group and a polymerizable monomer having a crosslinkable functional group in the side chain. Composition. The method of claim 1, wherein the epoxy-based silane coupling agent is 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-glycidoxyethyltrimethoxysilane and 2- (3 It is at least 1 type selected from the group which consists of a 4-4-epoxycyclohexyl) ethyl trimethoxysilane, and it is contained in 0.01-5 weight part with respect to 100 weight part of alkyl (meth) acrylate type copolymers. The antistatic adhesive composition according to claim 1, wherein the polyalkylene glycol-based silane coupling agent is at least one selected from polyethylene glycol propyl trimethoxy silane and polypropylene glycol propyl trimethoxy silane. The antistatic agent according to claim 1, wherein the antistatic agent is at least one selected from the group consisting of alkali metal salts and quaternary ammonium salts and is contained in an amount of 0.05 to 5.0 parts by weight based on 100 parts by weight of an alkyl (meth) acrylate copolymer. Pressure-sensitive adhesive composition. The method of claim 1, wherein the crosslinking agent is at least one member selected from the group consisting of melamine derivatives, polyisocyanate compounds, polyepoxy compounds and aziridine compounds, and is 0.1 to 100 parts by weight based on 100 parts by weight of an alkyl (meth) acrylate copolymer. Antistatic adhesive composition contained in 5.0 parts by weight. The polarizing plate in which the adhesive layer which consists of an antistatic adhesive composition of any one of Claims 1-6 was laminated | stacked. A liquid crystal display device comprising a polarizing plate according to claim 7 on at least one side of a liquid crystal cell.