KR20120091548A - Adhesive composition, polarizing plate and liquid crystal display device comprising the same - Google Patents

Abstract

PURPOSE: An adhesive composition is provided to reduce curing time without adding a crosslinking promoter, and to obtain excellent storage stability. CONSTITUTION: An adhesive composition comprises a copolymer consisting of 90-99.9 weight% of a (meth)acrylate monomer having an alkyl group, and 0.01-10 weight% of a monomer in chemical formula 1 comprising an aromatic carboxylic acid group, and a crosslinking agent. In chemical formula 1, R1 is H or CH3, R2 is H or CH3, X is S, O or NH, and R3 is a C0-1 alkene group or a phenyl group. A comprised amount of the monomer in chemical formula 1 is 0.1-3 weight% based on 100 weight% of the copolymer.

Description

Adhesive composition, polarizing plate and liquid crystal display including the same {ADHESIVE COMPOSITION, POLARIZING PLATE AND LIQUID CRYSTAL DISPLAY DEVICE COMPRISING THE SAME}

The present invention relates to a pressure-sensitive adhesive composition, a polarizing plate and a liquid crystal display including the same, which can shorten the curing period without adding a separate component and at the same time have excellent storage stability to ensure sufficient pot-life as well as to improve light leakage. will be.

A liquid crystal display device (LCD) includes a liquid crystal panel including a liquid crystal cell and a polarizing plate bonded to both surfaces of the liquid crystal cell via an adhesive layer.

The pressure-sensitive adhesive for bonding the liquid crystal cell and the polarizing plate must satisfy physical properties such as reworkability as well as adhesion to the substrate, light leakage resistance, heat and moisture resistance. In addition, the pressure-sensitive adhesive together with the above-mentioned physical properties is required to shorten the curing period to improve productivity.

As such, a method of using a crosslinking accelerator which promotes a crosslinking reaction has been proposed as a method for shortening the curing period while maintaining physical properties required as a conventional adhesive.

Korean Patent Publication No. 2009-0132116 discloses an adhesive composition comprising a Lewis base having a specific structure, and Korean Patent Publication No. 2008-0047030 discloses an adhesive composition containing a Lewis acid. Although the pressure-sensitive adhesive composition described in the above documents has an effect of shortening curing, the viscosity of the pressure-sensitive adhesive composition changes rapidly due to the addition of a crosslinking accelerator, which lowers the storage stability and shortens the pot-life of the pressure-sensitive adhesive, and thus the process It may cause stability problems.

An object of the present invention is to provide a pressure-sensitive adhesive composition that can shorten the curing period without adding a separate crosslinking promoter, and at the same time ensure excellent storage stability.

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

Another object of the present invention is to provide a liquid crystal display device having the polarizing plate on at least one side of a liquid crystal cell.

1. a copolymer of 90 to 99.99% by weight of a (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms and 0.01 to 10% by weight of a monomer of the formula (1) having an aromatic carboxylic acid group; And a crosslinking agent:

(Wherein R ₁ is H or CH ₃ ; R ₂ is H or CH ₃ ; X is S, O or NH; R ₃ is an alken group or phenyl group having 0 to 1 carbon atoms).

2. The pressure-sensitive adhesive composition of claim 1, wherein the monomer of Formula 1 is obtained by reacting the compound of Formula 2 with the compound of Formula 3 in the presence of a solvent and a catalyst:

Wherein R ₄ is H or CH ₃ ; R ₅ is OH, CH ₂ OH, hydroxyphenyl, SH, CH ₂ SH, NH _{2 ,} CH ₂ NH ₂ or aniline group; R ₆ is H or CH ₃ ).

3. In the above 1, the monomer of Formula 1 is a pressure-sensitive adhesive composition is a compound represented by the following formula (4):

4. In the above 1, the monomer of Formula 1 is included in the pressure-sensitive adhesive composition 0.1 to 3% by weight based on 100% by weight of the copolymer.

5. In the above 1, the crosslinking agent is an adhesive composition selected from the group consisting of an isocyanate compound and an epoxy compound.

6. The polarizing plate of the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition of any one of 1 to 5 above.

7. Liquid crystal display device having a polarizing plate of the above 6 on at least one side of the liquid crystal cell.

The pressure-sensitive adhesive composition according to the present invention can improve productivity by shortening the curing period without adding a crosslinking accelerator by applying a monomer containing an aromatic carboxylic acid group having a high activity of nucleophilic addition reaction to a copolymer. .

In addition, the pressure-sensitive adhesive composition of the present invention can suppress the change in viscosity while maintaining the physical properties required as a conventional pressure-sensitive adhesive is excellent in storage stability and can secure sufficient pot-life can also improve process stability.

In addition, the pressure-sensitive adhesive composition of the present invention can further improve the light leakage phenomenon by increasing the photoelastic coefficient without the addition of a separate component.

The present invention relates to a pressure-sensitive adhesive composition, a polarizing plate and a liquid crystal display including the same, which can shorten the curing period and add sufficient pot-life as well as improve light leakage phenomenon without adding a separate component. will be.

Hereinafter, the present invention will be described in detail.

The pressure-sensitive adhesive composition of the present invention comprises a copolymer of 90 to 99.99% by weight of a (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms and 0.01 to 10% by weight of a monomer of the formula (1) having an aromatic carboxylic acid group; And a crosslinking agent:

[Formula 1]

(Wherein R ₁ is H or CH ₃ ; R ₂ is H or CH ₃ ; X is S, O or NH; R ₃ is an alken group or phenyl group having 0 to 1 carbon atoms).

The copolymer of the present invention is characterized in that it is a copolymer of an aromatic carboxylic acid group having a high activity of nucleophilic addition reaction in the molecule, specifically a monomer containing a benzoic acid group.

The copolymer is preferably an acrylic copolymer in which a (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms and a monomer of formula (1) having an aromatic carboxylic acid group are copolymerized as an adhesive resin. Here, (meth) acrylate means both acrylate and methacrylate.

As a (meth) acrylate monomer which has a C1-C12 alkyl group, n-butyl (meth) acrylate, 2-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) Acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, pentyl (meth) acrylate, n-octyl (meth) acrylate, Isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, etc. are mentioned, These can be used individually or in mixture of 2 or more types. Among these, n-butyl acrylate, 2-ethylhexyl acrylate, or a mixture thereof is preferable.

The (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms is preferably contained in 90 to 99.99% by weight, more preferably 95 to 99.95% by weight relative to 100% by weight of the total monomers used in the production of the acrylic copolymer. It is good to be%. If the content is less than 90% by weight, the adhesive force is not sufficient, and if the content is more than 99.99% by weight cohesion may be lowered.

The monomer of Formula 1 is a monomer having a benzoic acid group which is an aromatic carboxylic acid group having high activity of nucleophilic addition reaction in the molecule, and accelerates the reaction between the acrylic copolymer and the following crosslinking agent to shorten the curing period and improve the photoelastic coefficient to improve the light leakage phenomenon. Ingredients that can be made:

[Formula 1]

(Wherein R ₁ is H or CH ₃ ; R ₂ is H or CH ₃ ; X is S, O or NH; R ₃ is an alken group or phenyl group having 0 to 1 carbon atoms).

Monomers of Formula 1 may be obtained, for example, by reacting a compound of Formula 2 with a compound of Formula 3 in the presence of a solvent and a catalyst:

[Formula 2]

,

,

(3)

Wherein R ₄ is H or CH ₃ ; R ₅ is OH, CH ₂ OH, hydroxyphenyl, SH, CH ₂ SH, NH _{2 ,} CH ₂ NH ₂ or aniline group; R ₆ is H or CH ₃ ).

Examples of the compound represented by the formula (2) include 4-hydroxybenzoic acid, 4- (hydroxymethyl) benzoic acid, 4-aminobenzoic acid, 4- (aminomethyl) benzoic acid, and 4'-hydroxy-4-biphenyl. Carboxylic acids and the like are preferred:

Examples of the compound of formula 3 include acryloyl chloride or methacryloyl chloride.

The solvent is not limited as long as it is an organic solvent used in a conventional synthesis, for example, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dichloromethane, methyl ethyl ketone, cyclohexanone, ethyl acetate, iso Propyl alcohol, and the like, and these may be used alone or in combination of two or more thereof.

Moreover, as a catalyst, a well-known catalyst can be used for synthesis, For example, organic tin compounds, such as dibutyl tin acetylacetonate, dibutyl tin dilaurate, dioctyl tin dilaurate, dibutyl tin octoate; Iron compounds such as iron acetylacetonate and ferric chloride; Tertiary amine catalysts, such as triethylamine and triethylenediamine, etc. are mentioned, These can be used individually or in combination of 2 or more types.

The monomer of the formula (1) is preferably 4-acryloyloxybenzoic acid represented by the following formula (4).

[Formula 4]

The monomer of Formula 1 is preferably included in 0.01 to 10% by weight, more preferably 0.05 to 5% by weight, most preferably 0.1 to 3% by weight relative to 100% by weight of the total monomers used in the production of the acrylic copolymer It is good to be%. If the content is less than 0.01% by weight, the crosslinking reaction promoting effect is insignificant and the cohesion may be lowered. If the content is more than 10% by weight, the change in viscosity is large, resulting in poor storage stability and poor adhesion.

In addition, the copolymer may be further included in a range in which other polymerizable monomers other than the monomers do not lower the adhesion, such as 10 wt% or less.

The production method of the copolymer is not particularly limited, and may be prepared using a method such as bulk polymerization, solution polymerization, emulsion polymerization or suspension polymerization, which are commonly used in the art, and solution polymerization is preferable. In addition, a solvent, a polymerization initiator, a chain transfer agent for molecular weight control, and the like, which are usually used in the polymerization, may be used.

The acrylic copolymer has a weight average molecular weight (polystyrene equivalent) measured by gel permeation chromatography (GPC) in general of 50,000 to 2,000,000, preferably 1,000,000 to 2,000,000.

The copolymer composed of the above components is a copolymer of a monomer containing a benzoic acid group, which is an aromatic carboxylic acid group having a high activity of nucleophilic addition reaction, in its molecule, which can shorten the curing period due to its high reactivity and increase the photoelastic coefficient. Light leakage can also be improved.

A crosslinking agent is a component for strengthening the cohesion force of an adhesive by crosslinking a copolymer suitably, The kind is not specifically limited. For example, an isocyanate type compound, an epoxy type compound, etc. are mentioned, These can be used individually or in mixture of 2 or more types.

As the isocyanate compound, tolylene diisocyanate, xylene diisocyanate, 2,4-diphenylmethane diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tetramethyl xylene diisocyanate Diisocyanate compounds such as naphthalene diisocyanate; Diisocyanate obtained from 2 moles of an adduct obtained by reacting 3 moles of a diisocyanate compound with 1 mole of a polyhydric alcohol compound such as trimethylolpropane, an isocyanurate obtained by self-condensing 3 moles of the diisocyanate compound, and 3 moles of the diisocyanate compound And polyfunctional isocyanate compounds containing three functional groups such as biuret, triphenylmethanetriisocyanate, and methylenebistriisocyanate, in which the remaining 1 mole of diisocyanate is condensed to urea.

As the epoxy compound, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, poly Propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polytetramethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl Ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, resorcin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, trimethylol propane triglycidyl ether, penta Erythritol polyglycidyl ether, sorbitol polyglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, tris (glycidyl) iso Anurate, tris (glycidoxyethyl) isocyanurate, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane, N, N, N ', N'-tetraglycidyl-m -Xylylenediamine, etc. are mentioned.

The crosslinking agent is preferably included in an amount of 0.01 to 15 parts by weight, and more preferably 0.1 to 5 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 parts by weight, the cohesion force becomes small due to insufficient crosslinking degree, which may cause durability deterioration such as lifting and damage of cutting property. If the content is more than 15 parts by weight, light leakage may occur due to excessive crosslinking reaction.

In addition, the pressure-sensitive adhesive composition may further include a silane coupling agent.

The kind of the silane coupling agent is not particularly limited, and for example, vinylchlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxy Propyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-metha Krilloxypropyl triethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyl diethoxysilane, 3-acryloxypropyl trimethoxysilane , N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyl Methyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyl Dimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatepropyltriethoxysilane, and the like. These can be used individually or in mixture of 2 or more types.

The silane coupling agent may be included in an amount of 0 to 10 parts by weight based on 100 parts by weight of the acrylic copolymer based on the solid content, preferably 0.005 to 5 parts by weight. If the content is more than 10 parts by weight, durability may be reduced.

In addition to the above components, the pressure-sensitive adhesive composition is a tackifying resin, antioxidant, corrosion inhibitor, leveling agent, surface lubricant in order to adjust the adhesion, cohesion, viscosity, elastic modulus, glass transition temperature, antistatic properties, etc. required according to the application It may further include additives such as dyes, pigments, antifoaming agents, fillers, light stabilizers, antistatic agents.

The pressure-sensitive adhesive composition thus constructed includes a copolymer in which monomers containing benzoic acid groups, which are aromatic carboxylic acid groups, are copolymerized in the molecule while maintaining physical properties required as conventional pressure-sensitive adhesives, without the addition of a crosslinking accelerator, which has been used to promote crosslinking reactions. It can shorten the period and improve the light leakage phenomenon by increasing the photoelastic coefficient. In addition, since the addition of a separate component is excellent storage stability and process stability can be improved.

The pressure-sensitive adhesive composition of the present invention can be used both as a pressure-sensitive adhesive for surface protection film as well as pressure-sensitive adhesive for polarizing plate for bonding with a liquid crystal cell. In addition, it can be used as a protective film, a reflective sheet, a structural adhesive sheet, a photo adhesive sheet, a lane display adhesive sheet, an optical adhesive product, an adhesive for an electronic component, as well as a general commercial adhesive sheet product and a medical patch.

The polarizing plate of the present invention is characterized in that an adhesive layer made of an adhesive composition is laminated.

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㎛.

Such a polarizing plate can be applied to all conventional liquid crystal display devices, and in particular, a polarizing plate in which an adhesive layer is stacked may constitute a liquid crystal display device including a liquid crystal panel provided on at least one side of a liquid crystal cell.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but these examples are merely illustrative of the present invention and are not intended to limit the scope of the appended claims. It is apparent to those skilled in the art that various changes and modifications can be made to the present invention, and such modifications and changes belong to the appended claims.

Example

Synthesis Example 1. Synthesis of 4-acryloyloxybenzoic acid

The round bottom flask (1 L) was immersed in an ice bath at 0 ° C., 100 g of 4-hydroxybenzoic acid and 300 g of dichloromethane solvent were added, followed by stirring for 30 minutes to mix. 50 g of acryloyl chloride was slowly added thereto by dropwise addition for 10 minutes. Subsequently, 100 g of triethylamine was added dropwise for 30 minutes, followed by further stirring at room temperature for 30 minutes, and then 500 ml of distilled water was added and stirred for 10 minutes. After stirring was complete, the dichloromethane solvent layer was separated using a separatory funnel, and the solvent was removed by distillation under reduced pressure to obtain 4-acryloyloxybenzoic acid (4-AOBA) of Chemical Formula 4.

The NMR analysis of the obtained compound is as follows:

¹ H NMR (200 MHz, CDCl ₃ ), 5.82 (m, CH), 6.03 (m, CH), 6.23 (m, CH), 7.25 (d, CH), 8.23 (d, CH), 11.18 (s, OH).

[Formula 4]

Synthesis Example 2. Synthesis of 4-acrylamidebenzoic acid

In the same manner as in Synthesis example 1, using 4-aminobenzoic acid instead of 4-hydroxybenzoic acid to obtain 4-acrylamidebenzoic acid (4-AABA) of the formula (5).

The NMR analysis of the obtained compound is as follows:

¹ H NMR (200 MHz, CDCl ₃ ), 5.64 (m, CH), 6.43 (m, CH), 6.17 (m, CH), 7.65 (d, CH), 8.07 (S, NH), 8.13 (d, CH), 11.23 (s, OH).

[Chemical Formula 5]

Preparation Example 1 Preparation of Acrylic Copolymer A

97 parts by weight of n-butyl acrylate (BA) and 3 parts of 4-acryloyloxybenzoic acid (4-AOBA) obtained in Synthesis Example 1 in a 1 L reactor equipped with a refrigeration device to allow nitrogen gas to reflux and for easy temperature control. After adding a monomer mixture consisting of parts, 100 parts by weight of ethyl acetate (EA) was added as a solvent. Thereafter, nitrogen gas was added for 1 hour to remove oxygen, and then the temperature was maintained at 62 ° C. After stirring the monomer mixture uniformly, 0.07 parts by weight of azobisisobutyronitrile (AIBN) was added as a reaction initiator and reacted for 8 hours to prepare an acrylic copolymer A having a weight average molecular weight of 800,000 or more.

Preparation Example 2-7. Manufacture of Acrylic Copolymer B-G

To carry out the same as in Preparation Example 1, a monomer mixture as shown in Table 1 was used.

division designation Monomer (parts by weight) BA 4-AOBA 4-AABA AA Preparation Example 1 A 97 3 - - Preparation Example 2 B 99.05 0.05 - - Production Example 3 C 99 One - - Production Example 4 D 95 5 - - Production Example 5 E 92 8 - - Production Example 6 F 97 - 3 - Preparation Example 7 G 97 - - 3 BA: n-butylacrylate
4-AOBA: 4-acryloyloxybenzoic acid
4-AABA: 4-acrylamidebenzoic acid
AA: acrylic acid

Example 1

(1) pressure-sensitive adhesive composition

100 parts by weight of the acrylic copolymer A prepared in Preparation Example 1 based on the solid content, 0.5 parts by weight of hexamethylene diisocyanate adduct (COR-HXR, Nippon Polyurethane Co., Ltd.) of trimethylolpropane as a crosslinking agent, and a silane coupling agent. 0.3 parts by weight of 3-glycidoxypropyltrimethoxysilane (KBM-403, Shin-Etsu) was mixed and then diluted to an appropriate concentration in consideration of coating properties to prepare an adhesive composition.

(2) adhesive sheet

The pressure-sensitive adhesive composition was dried on a film coated with a silicone release agent and then applied to have a thickness of 25 μm, and dried at 100 ° C. for 1 minute to form a pressure-sensitive adhesive layer. An adhesive sheet was prepared by laminating another release film thereon.

Example  2

The same procedure as in Example 1, except that the acrylic copolymer B prepared in Preparation Example 2 in (1).

Example 3

In the same manner as in Example 1, but using the acrylic copolymer C prepared in Preparation Example 3 in (1).

Example 4

The same process as in Example 1, except that the acrylic copolymer D prepared in Preparation Example 4 in (1).

Example 5

The same procedure as in Example 1, except that the acrylic copolymer E prepared in Preparation Example 5 in (1).

Example 6

The same procedure as in Example 1, except that the acrylic copolymer F prepared in Preparation Example 6 in (1).

Comparative Example 1

In the same manner as in Example 1, the acrylic copolymer G prepared in Preparation Example 7 in (1) was used.

Comparative Example 2

In the same manner as in Example 1, but using the acrylic copolymer G prepared in Preparation Example 7 in (1), 0.1 parts by weight of dibutyl tin dilaurate was used as a crosslinking accelerator.

Test Example

Physical properties of the pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet prepared in Examples and Comparative Examples were measured by the following method, and the results are shown in Table 2 below.

1. Curing period

While curing the prepared pressure-sensitive adhesive sheet at 23 ° C., 65% RH for 1 to 10 days, the gel fraction was measured by the following method on a daily basis, and the gel fraction was no longer increased, that is, the curing period was measured.

About 0.25 g of an adhesive layer of an adhesive sheet is affixed on a fixed 250 mesh wire mesh (100 mm x 100 mm), and it wraps so that a gel powder may not leak. After accurate weighing by precision balance, the wire mesh is immersed in ethyl acetate solution for 3 days. The immersed wire mesh is taken out, washed with a small amount of ethyl acetate solution, dried at 120 ° C. for 24 hours, and weighed. The gel fraction was calculated by the following equation 1 using the measured weight.

[Wherein, A is the weight of the wire mesh (g), B is the weight of the wire mesh with the adhesive layer (BA: adhesive weight, g), C is the weight of the dried wire mesh after immersion (CA: weight of the gelled resin, g )being].

2. Storage stability (viscosity change,%)

Initial viscosity of the prepared pressure-sensitive adhesive composition and the viscosity after standing for 24 hours at room temperature was measured using a viscometer (Brookfield LVDV-II + type B (spindle no. 3, 30rpm)). The rate of change (Δη) of the measured viscosity was calculated. At this time, when the viscosity change (Δη) is 30% or less, it was determined that the storage stability is excellent.

3. Light leakage phenomenon

After peeling the release film of the prepared pressure-sensitive adhesive sheet to the pressure-sensitive adhesive layer on an iodine-based polarizing plate of 185㎛ thickness to prepare a polarizing plate with a pressure-sensitive adhesive, and bonded it to both sides of a glass substrate (# 1737, Corning) 50 ℃, Specimens were prepared by autoclaving for 30 minutes under 5 atmospheres. The prepared specimens were left in an 80 ° C. oven for 24 hours and immediately placed on a backlight in a dark room, and photographed by visually confirming the degree of light leakage.

<Evaluation Criteria>

(Circle): It is difficult to visually distinguish light leakage phenomenon.

△: Some light leakage phenomenon.

×: Light leakage phenomenon is clearly identified.

division Curing period (days) Δη (%) Light leakage phenomenon Example 1 2 9 ○ Example 2 3 One △ Example 3 2 5 ○ Example 4 One 15 ○ Example 5 One 20 ○ Example 6 2 8 ○ Comparative Example 1 7 One ○ Comparative Example 2 2 200 ×

As shown in Table 2, the pressure-sensitive adhesive composition of Examples 1 to 6 comprising an acrylic copolymer copolymerized with a monomer having a benzoic acid group in the molecule according to the present invention and a crosslinking agent has a storage stability compared to that of Comparative Examples 1 and 2 It was found to be excellent and shorten the curing period, as well as improve the light leakage phenomenon. Particularly, when the monomer having an aromatic carboxylic acid group in the acrylic copolymer is contained in 0.1-3% by weight, it was preferable because it exhibited better effects in terms of all physical properties.

Claims (7)

A copolymer of 90 to 99.99% by weight of a (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms and 0.01 to 10% by weight of a monomer of the formula (1) having an aromatic carboxylic acid group; And
Pressure-sensitive adhesive composition comprising a crosslinking agent:
[Formula 1]

(Wherein R ₁ is H or CH ₃ ; R ₂ is H or CH ₃ ; X is S, O or NH; R ₃ is an alken group or phenyl group having 0 to 1 carbon atoms).
The pressure-sensitive adhesive composition of claim 1, wherein the monomer of Formula 1 is obtained by reacting a compound of Formula 2 with a compound of Formula 3 in the presence of a solvent and a catalyst:
(2)

,
(3)

Wherein R ₄ is H or CH ₃ ; R ₅ is OH, CH ₂ OH, hydroxyphenyl, SH, CH ₂ SH, NH _{2 ,} CH ₂ NH ₂ or aniline group; R ₆ is H or CH ₃ ).
The pressure-sensitive adhesive composition of claim 1, wherein the monomer of Formula 1 is a compound represented by Formula 4 below:
[Chemical Formula 4]

.
The pressure-sensitive adhesive composition of claim 1, wherein the monomer of Formula 1 is included in an amount of 0.1 to 3% by weight based on 100% by weight of the copolymer.
The pressure-sensitive adhesive composition of claim 1, wherein the crosslinking agent is at least one selected from the group consisting of an isocyanate compound and an epoxy compound.
The polarizing plate in which the adhesive layer which consists of an adhesive composition of any one of Claims 1-5 was laminated | stacked.
A liquid crystal display device comprising the polarizing plate of claim 6 on at least one side of the liquid crystal cell.