KR20140045785A - Adhesive composition - Google Patents

Abstract

The present invention relates to a pressure-sensitive adhesive composition, and more specifically, by containing an acrylic copolymer having a primary alcohol group, an acrylic copolymer having a carboxyl group, an aromatic isocyanate crosslinking agent and an epoxy crosslinking agent, the bending property is improved by stress relaxation and stress It relates to a pressure-sensitive adhesive composition as well as preventing light leakage due to concentration.

Description

[0001] ADHESIVE COMPOSITION [0002]

The present invention relates to a pressure-sensitive adhesive composition with excellent durability while preventing light leakage due to stress concentration.

In general, a liquid crystal display device (LCD) is provided with a liquid crystal cell and a polarizing plate containing a liquid crystal, and an appropriate pressure-sensitive adhesive layer for bonding them is used.

In order to protect the polarizer and the polarizer, the polarizing plate is laminated with protective films such as triacetyl cellulose (TAC). In addition, it may additionally include a wide viewing angle compensation film and a functional film.

At this time, each film is made of a material having a different molecular structure and composition and thus have different physical properties. In particular, under high temperature or high temperature and high humidity conditions, dimensional stability due to shrinkage or expansion of materials having a unidirectional molecular arrangement is insufficient. Therefore, when the polarizing plate is fixed by the pressure-sensitive adhesive, stress is concentrated in the TAC layer by contraction or expansion of the polarizing plate under high temperature or high temperature and high humidity conditions, and thus the polarizing plate is bent, which causes a light leakage phenomenon.

Such warpage can be suppressed by adjusting the stress relaxation property of the pressure-sensitive adhesive fixed to the polarizing plate so that residual stress does not remain, which can be achieved when the pressure-sensitive adhesive is uncrosslinked.

Accordingly, a crosslinkable copolymer, a noncrosslinkable copolymer, and a crosslinking agent are contained, and an adhesive having a SEMI-INTER PENETRATING NETWORK structure has been proposed [Korean Patent No. 948,778]. The pressure-sensitive adhesive is excellent in fluidity and stress relaxation characteristics, but recently there was a limit that does not show the durability suitable for the trend of the size of the polarizing plate and thinning.

In addition, a pressure-sensitive adhesive having an INTER PENETRATING NETWORK structure containing a crosslinkable copolymer, a crosslinking agent, a polyfunctional acrylate monomer and a photoinitiator has been proposed [Korean Patent No. 983,026]. The pressure-sensitive adhesive is able to implement the durability that can satisfy the recent trend, but it is difficult to secure the stress relaxation property there was a limit that warpage occurs.

The present invention is to provide a pressure-sensitive adhesive composition excellent in durability as well as preventing light leakage phenomenon by reducing the occurrence of warpage by stress relaxation.

In order to achieve the above object, the present invention provides an adhesive composition containing an acrylic copolymer having a primary alcohol group, an acrylic copolymer having a carboxyl group, an aromatic isocyanate crosslinking agent and an epoxy crosslinking agent.

The acrylic copolymer having a primary alcohol group may contain at least one monomer selected from the following formulas (1) to (5).

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 2 to 12)

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 12)

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 10)

Wherein R ₁ is a hydrogen atom or a methyl group

(Wherein R ₁ is a hydrogen atom or a methyl group).

The acrylic copolymer having a primary alcohol group may contain a (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms and at least one monomer selected from Formulas 1 to 5.

The at least one monomer selected from Formulas 1 to 5 may contain 0.1 to 10 parts by weight based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms.

The acrylic copolymer having a carboxyl group may contain at least one monomer selected from the following formulas (6) to (9).

Wherein R ₁ is a hydrogen atom or a methyl group

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 5)

(Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkyl group having 1 to 12 carbon atoms or an aryl group having 5 to 10 carbon atoms)

(Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkyl group having 1 to 12 carbon atoms or an aryl group having 5 to 10 carbon atoms)

The acrylic copolymer having a carboxyl group may contain a (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms and at least one monomer selected from Formulas 6 to 9.

The at least one monomer selected from Formulas 6 to 9 may contain 0.01 to 5 parts by weight based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms.

Acrylic copolymer containing 60 to 95% by weight of the acrylic copolymer having a primary alcohol group and 5 to 40 parts by weight of an acrylic copolymer having a carboxyl group, and 0.1 to 5% by weight of an aromatic isocyanate crosslinking agent based on 100 parts by weight of the acrylic copolymer. Part and an epoxy-based crosslinking agent may contain 0.01 to 0.5 parts by weight.

The pressure-sensitive adhesive composition of the present invention can be usefully used in fields such as polarizing plates and liquid crystal display devices because the pressure-reduced warpage lowers the occurrence of warpage and prevents light leakage due to stress concentration.

The present invention relates to a pressure-sensitive adhesive composition with excellent durability while preventing light leakage due to stress concentration.

Hereinafter, the present invention will be described in detail.

The adhesive composition of this invention contains the acryl-type copolymer which has a primary alcohol group, the acryl-type copolymer which has a carboxy group, an aromatic isocyanate type crosslinking agent, and an epoxy type crosslinking agent.

In the present invention, an acrylic copolymer having a primary alcohol group and an acrylic copolymer having a carboxyl group form an inter penetrating network (IPN) structure.

Specifically, in the present invention, a crosslinking reaction is performed between a single type of acryl-based copolymer based on the relative degree of steric hindrance between the acryl-based copolymer and the crosslinking agent and the difference in the reaction rate of the crosslinking agent. Form.

The aromatic isocyanate crosslinking agent is mainly involved in the crosslinking reaction of the acrylic copolymer having a primary alcohol group, and the epoxy crosslinking agent is mainly involved in the crosslinking reaction of the acrylic copolymer having a carboxyl group.

However, the aromatic isocyanate crosslinking agent may be involved in the crosslinking reaction of the acrylic copolymer having a carboxyl group. However, since the crosslinking reaction is performed in a very small amount, most of the copolymers form an inter penetrating network (IPN) structure and have physicochemical properties due to the IPN structure.

The present invention does not use radical crosslinking of a multifunctional acrylate for forming an existing IPN structure, and forms an IPN structure by applying a double crosslinking system of urethane and ester crosslinking having a small number of crosslinking functional groups and a relatively long crosslinking length. Compared with the pressure-sensitive adhesive composition of the IPN structure, the stress relaxation property is improved and at the same time, the durability is excellent.

The acrylic copolymer having a primary alcohol group is copolymerized with at least one monomer selected from the following formulas (1) to (5). At least one monomer selected from Formulas 1 to 5 is a crosslinkable monomer component that enhances cohesive force or adhesive strength of the pressure-sensitive adhesive composition by chemical bonding to impart durability and cutability.

[Chemical Formula 1]

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 2 to 12)

(2)

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 12)

(3)

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 10)

[Chemical Formula 4]

Wherein R ₁ is a hydrogen atom or a methyl group

[Chemical Formula 5]

(Wherein R ₁ is a hydrogen atom or a methyl group).

Considering the durability, stress relaxation property, etc. of an adhesive composition at the same time, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylamide, a hydride Preference is given to using oxymethyl (meth) acrylamide and the compound of formula (4).

It is preferable that the acryl-type copolymer which has a primary alcohol group of this invention contains the (meth) acrylate monomer which has a C1-C12 alkyl group, and 1 or more types of monomers chosen from the said Formula (1-5). In the present invention, (meth) acrylate means acrylate and methacrylate.

Examples of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms include n-butyl (meth) acrylate, 2-butyl (meth) acrylate, t-butyl (meth) acrylate, and 2-ethylhexyl (meth). ) Acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate, propyl (meth) acrylate, pentyl (meth) acrylate, n-octyl (meth) acrylate, Isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, and the like, among which n-butyl acrylate, 2-ethylhexyl acrylate or Mixtures of these are preferred. These may be used alone or in combination of two or more.

The at least one monomer selected from Formulas 1 to 5 may be included in an amount of 0.1 to 10 parts by weight, more preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms. Madam is good. When the content is less than 0.1 part by weight, the cohesive force of the pressure-sensitive adhesive becomes small and durability may be deteriorated. When the content is more than 10 parts by weight, a high gel fraction may deteriorate the adhesive strength and cause durability problems.

The acrylic copolymer of the present invention may further contain other polymerizable monomers other than the above monomers in a range not lowering the adhesive force, for example, 10 parts by weight or less based on the total amount.

The method for producing the copolymer is not particularly limited and can be produced by methods 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 polymerization can be used.

The acrylic copolymer preferably has a weight average molecular weight (polystyrene conversion, Mw) of 50,000 to 2,000,000, more preferably 400,000 to 2,000,000 as measured by Gel Permeation Chromatography (GPC). When the weight-average molecular weight is less than 50,000, cohesion between co-polymers may be insufficient, which may cause problems in adhesion durability. If the weight average molecular weight is more than 2,000,000, a large amount of a diluting solvent may be required in order to ensure fairness in coating.

It is preferable to contain 60-95 weight% of acrylic copolymers which have such a primary alcohol group, and 70-90 weight% is more preferable. If the content is less than 60% by weight may be insufficient durability, when it exceeds 95% by weight may be insufficient stress relaxation characteristics.

The acrylic copolymer having a carboxyl group may be copolymerized by containing one or more monomers selected from the following Chemical Formulas 6 to 9. In this case, at least one monomer selected from Chemical Formulas 6 to 9 also serves as a crosslinkable monomer.

[Chemical Formula 6]

Wherein R ₁ is a hydrogen atom or a methyl group

[Formula 7]

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 5)

[Chemical Formula 8]

(Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkyl group having 1 to 12 carbon atoms or an aryl group having 5 to 10 carbon atoms)

[Chemical Formula 9]

(Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkyl group having 1 to 12 carbon atoms or an aryl group having 5 to 10 carbon atoms)

In consideration of the durability, stress relaxation property and the like of the double pressure-sensitive adhesive composition at the same time, acrylic acid, methacrylic acid, carboxyethyl acrylate are preferred, and acrylic acid is more preferred.

It is preferable that the acryl-type copolymer which has a carboxyl group of this invention contains the (meth) acrylate monomer which has a C1-C12 alkyl group, and 1 or more types of monomers chosen from the said Formulas 6-9.

The at least one monomer selected from Chemical Formulas 6 to 9 is preferably included in an amount of 0.01 to 5 parts by weight, and more preferably 0.05 to 2 parts by weight, based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms. Madam is good. If the content is less than 0.01 parts by weight, the cohesive force of the pressure-sensitive adhesive may be reduced, the durability may be lowered.

In addition, the kind of the (meth) acrylate monomer which has a C1-C12 alkyl group, the polymerization method, the weight average molecular weight of the produced acrylic copolymer, etc. are the same as the copolymer which has the said primary alcohol group.

It is preferable to contain 5-40 weight% of acrylic copolymers which have such a carboxyl group, and 10-30 weight% is more preferable. If the content is less than 5% by weight may be insufficient stress relaxation performance, if the content exceeds 40% by weight may endurance.

An aromatic diisocyanate crosslinking agent and an epoxy crosslinking agent are components which strengthen the cohesion force of an adhesive by crosslinking an acryl-type copolymer suitably.

The aromatic diisocyanate crosslinking agent is involved in the crosslinking reaction of the acrylic copolymer having a primary alcohol group. Specifically, it may be in the form of an adduct of tolylene diisocyanate, isocyanurate thereof or polyhydric alcohol.

Such aromatic diisocyanate-based crosslinking agent is preferably contained 0.1 to 5 parts by weight, more preferably 0.5 to 1.5 parts by weight based on 100 parts by weight of the total content of the acrylic copolymer having a primary alcohol group and the acrylic copolymer having a carboxyl group. If the content is less than 0.1 part by weight may be a decrease in durability, if the content exceeds 5 parts by weight may be a concern of simultaneous degradation of durability and stress relaxation properties.

The epoxy crosslinking agent is involved in the crosslinking reaction of the acrylic copolymer having a carboxyl group. Specifically, ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, N, N, N ', N'- tetraglycidyl-1,3-xylenediamine, or glycerin digly Cydyl ether and the like can be used.

 The epoxy crosslinking agent is preferably contained in an amount of 0.01 to 0.5 parts by weight, more preferably 0.01 to 0.05 parts by weight, based on 100 parts by weight of the total content of the acrylic copolymer having a primary alcohol group and the acrylic copolymer having a carboxyl group. If the content is less than 0.01 parts by weight may be a decrease in durability, if the content is more than 0.5 parts by weight may be a reduction in stress relaxation properties.

In addition to the above components, the pressure-sensitive adhesive composition may further contain various additives such as a silane coupling agent, a tackifier resin, an antioxidant, a leveling agent, a surface lubricant, a dye, an antioxidant, and the like in order to control the adhesion, cohesion, viscosity, A pigment, a defoaming agent, a filler, a light stabilizer, an antistatic agent, and the like.

The double silane coupling agent is preferably contained in order to improve adhesion between the pressure-sensitive adhesive and the base material. It is preferable that the double silane coupling agent contains an alkoxysilane containing a functional group such as amino group, epoxy group, acetoacetyl group, polyalkylene glycol group, acrylic group, Can be used.

The amount of such an additive may be suitably controlled within a range that does not impair the effect of the present invention. For example, the silane coupling agent may be contained in an amount of 0.1 to 2 parts by weight based on 100 parts by weight of the acrylic copolymer in consideration of adhesion strength and durability have.

In particular, the pressure-sensitive adhesive composition of the present invention can be used as a pressure-sensitive adhesive for polarizing plates and a surface protective film for bonding to liquid crystal cells. In addition, it can be used as a general commercial adhesive sheet product as well 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 adhesive for electronic parts, and the like.

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.

Manufacturing example  : Acrylic copolymer preparation

Manufacturing example  A: 1st Alcohol groups  Acrylic copolymer

Manufacturing example  A-1

92 parts by weight of n-butyl acrylate (BA), 7 parts by weight of methyl acrylate (MA), 2-hydroxyethyl acrylate 1.0 in a 1 L reactor equipped with a refrigeration system to allow nitrogen gas to reflux and facilitate temperature control After adding the monomer mixture consisting of parts by weight, 100 parts by weight of acetone was added as a solvent. Then, after purging nitrogen gas for 1 hour to remove oxygen, it was maintained at 55 ℃. After homogenizing the mixture, 0.02 parts by weight of azobisisobutyronitrile (AIBN) was added as a reaction initiator, and reacted for 12 hours to have a primary alcohol group having a weight average molecular weight of about 1.5 million. Acrylic copolymer.

Manufacturing example  A-2

The same procedure as in Preparation Example A-1, except that 2-hydroxyethyl acrylate has a primary alcohol group using Chemical Formula 4 (wherein R ₁ is hydrogen). Acrylic copolymer.

Manufacturing example  A-3

In the same manner as in Preparation Example A-1, using 4-hydroxybutyl acrylate instead of 2-hydroxyethyl acrylate having a primary alcohol group Acrylic copolymer.

Manufacturing example  A-4

The same procedure as in Production Example A-1, except that 4-hydroxybutyl vinyl ether is used instead of 2-hydroxyethyl acrylate to have a primary alcohol group. Acrylic copolymer.

Manufacturing example  A-5

In the same manner as in Preparation Example A-1, 92.5 parts by weight of n-butyl acrylate (BA) and 2-instead of 92 parts by weight of n-butyl acrylate (BA) and 1 part by weight of 2-hydroxyethyl acrylate. 0.5 parts by weight of hydroxyethyl acrylate having a primary alcohol group Acrylic copolymer.

Manufacturing example  A-6

In the same manner as in Preparation Example A-1, 90 parts by weight of n-butyl acrylate (BA) and 2-instead of 92 parts by weight of n-butyl acrylate (BA) and 1 part by weight of 2-hydroxyethyl acrylate. Using 3 parts by weight of hydroxyethyl acrylate having a primary alcohol group Acrylic copolymer.

Manufacturing example  B: Carboxy group  Acrylic copolymer

Manufacturing example  B-1

99.9 parts by weight of n-butyl acrylate (BA) and 0.1 parts by weight of acrylic acid were added to a 1 L reactor equipped with a refrigeration system for easy reflux of nitrogen gas, and then 100 parts by weight of acetone as a solvent. Input. Then, after purging nitrogen gas for 1 hour to remove oxygen, it was maintained at 65 ℃. After uniformizing the mixture, 0.1 part by weight of azobisisobutyronitrile (AIBN) was added as a reaction initiator, and reacted for 6 hours to have a carboxyl group having a weight average molecular weight of about 400,000. Acrylic copolymer.

Manufacturing example  B-2

The same procedure as in Preparation Example B-1, except that carboxyethyl acrylate is used instead of acrylic acid to have a carboxyl group. Acrylic copolymer.

Manufacturing example  B-3

Carried out in the same manner as in Preparation Example B-1, using 99.9 parts by weight of n-butyl acrylate (BA) and 99.98 parts by weight of n-butyl acrylate (BA) and 0.02 part by weight of acrylic acid instead of 0.1 parts by weight of acrylic acid. Having Acrylic copolymer.

Manufacturing example  B-4

Carried out in the same manner as in Preparation Example B-1, using 99.9 parts by weight of n-butyl acrylate (BA) and 0.1 parts by weight of acrylic acid, 99.7 parts by weight of n-butyl acrylate (BA) and 0.3 parts by weight of acrylic acid. Having Acrylic copolymer.

Manufacturing example  C-1: Reactivity Functional group  Free Acrylic Copolymer

The same procedure as in Preparation Example B-1, except that 100 parts by weight of n-butyl acrylate (BA) was used to prepare an acrylic copolymer.

Example  1-13 and Comparative Example  1-4

As shown in Table 1 below, an acrylic copolymer having a primary alcohol group, an acrylic copolymer having a carboxyl group, an aromatic isocyanate crosslinking agent, an epoxy crosslinking agent, and a silane coupling agent (3-glycidoxypropyltrimethoxysilane, KBM-403 , Shin-Etsu Co., Ltd.) was mixed with 0.5 part by weight based on 100 parts by weight of the acrylic copolymer, and then diluted in an organic solvent to prepare an adhesive composition.

division
(Parts by weight) Acrylic copolymer Cross-linking agent Primary alcohol group Carboxy group Cor-l Tetrad-X C-1 A-1 A-2 A-3 A-4 A-5 A-6 B-1 B-2 B-2 B-4 Example 1 80 - - - - - 20 - - - 0.8 0.02 - Example 2 - 80 - - - - 20 - - - 0.8 0.02 - Example 3 - - 80 - - - 20 - - - 0.8 0.02 - Example 4 - - - 80 - - 20 - - - 0.8 0.02 - Example 5 - - - - 80 - 20 - - - 0.5 0.02 - Example 6 - - - - - 80 20 - - - 1.0 0.02 - Example 7 80 - - - - - - 20 - - 0.8 0.02 - Example 8 80 - - - - - - - 20 - 0.8 0.02 - Example 9 80 - - - - - - - - 20 0.8 0.05 - Example 10 90 - - - - - 10 - - - 0.8 0.02 - Example 11 70 - - - - - 30 - - - 0.8 0.02 - Example 12 80 - - - - - 20 - - - 1.5 0.01 - Example 13 80 20 0.8 - 0.02 Comparative Example 1 100 - - - - - - - - - 1.0 - - Comparative Example 2 - - - - - - 100 - - - - 1.0 - Comparative Example 3 80 - - - - - 20 - - - 1.0 - - Comparative Example 4 80 - - - - - 20 - - - - 1.0 - Cor-L: coronate-L (tolylene diisocyanate adduct of trimethylolpropane, product of Nippon Polyurethane Co., Ltd.)
Tetrad-X: N, N, N ', N'-tetraglycidyl-1,3-xylenediamine (Mitsubishi Gas Corporation)
C-1: triglycidyl ether isocyanurate
Crosslinking agent is parts by weight based on 100 parts by weight of the acrylic copolymer

Comparative Example  5

In the same manner as in Example 1, but having a carboxyl group of Preparation Example B-1 An adhesive composition was prepared using the acrylic copolymer of Preparation Example C-1 instead of the acrylic copolymer.

Comparative Example  6

1,6-hexanediol diacrylate (HDDA) in a mixture of 100 parts by weight of the acrylic copolymer having a primary alcohol group of Production Example A-1 and 1.0 part by weight of tolylene diisocyanate adduct (TDI-1) of trimethylolpropane 10 parts by weight and 1 part by weight of a, a-methoxy-a-hydroxyacetophenone (Irgacure # -651) were added thereto, followed by sufficiently stirring to prepare an adhesive composition.

Test Example

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

1.Bending

The prepared pressure-sensitive adhesive polarizing plate was bonded to one surface of 17-inch Corning glass and autoclaved. Then, the resultant was heat-treated at 80 ° C. for 100 hours, left at room temperature for 24 hours, and then placed on a flat surface to have a high flatness. The bending characteristic was confirmed by measuring the distance to a side. At this time, when the height is 10 mm or less, it is determined that the bending property is good.

2. Adhesive durability

The release film of the polarizing plate with pressure-sensitive adhesive was peeled off, the surface of the pressure-sensitive adhesive layer was bonded to Corning glass, and after standing at 60 ° C. for 300 hours, the appearance was confirmed (heat resistance test).

<Evaluation Criteria>

Bubbles and peeling phenomenon are observed: x

Bubbles and Peelings Unidentified: ○

division Deflection (/ mm) Adhesive durability Example 1 4 ○ Example 2 2 ○ Example 3 3 ○ Example 4 2 ○ Example 5 3 ○ Example 6 6 ○ Example 7 5 ○ Example 8 One ○ Example 9 6 ○ Example 10 5 ○ Example 11 3 ○ Example 12 3 ○ Example 13 4 ○ Comparative Example 1 21 ○ Comparative Example 2 One × Comparative Example 3 14 ○ Comparative Example 4 10 ○ Comparative Example 5 2 × Comparative Example 6 22 ○

As shown in Table 2, the pressure-sensitive adhesive composition of Examples 1 to 13 containing an acrylic copolymer having a primary alcohol group, an acrylic copolymer having a carboxyl group, an aromatic isocyanate crosslinking agent and an epoxy crosslinking agent according to the present invention are Comparative Examples 1 to 13. Compared with 6, it was confirmed that the warpage was less generated and the durability was excellent at the same time.

Claims (8)

An adhesive composition containing an acrylic copolymer having a primary alcohol group, an acrylic copolymer having a carboxyl group, an aromatic isocyanate crosslinking agent and an epoxy crosslinking agent.
The pressure-sensitive adhesive composition of claim 1, wherein the acrylic copolymer having a primary alcohol group contains at least one monomer selected from the following Chemical Formulas 1-5:
[Chemical Formula 1]

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 2 to 12)
(2)

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 12)
(3)

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 10)
[Chemical Formula 4]

Wherein R ₁ is a hydrogen atom or a methyl group
[Chemical Formula 5]

(Wherein R ₁ is a hydrogen atom or a methyl group).
The pressure-sensitive adhesive composition of claim 2, wherein the acrylic copolymer having a primary alcohol group contains a (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms and at least one monomer selected from Formulas 1 to 5.
The pressure-sensitive adhesive composition of claim 3, wherein the at least one monomer selected from Formulas 1 to 5 contains 0.1 to 10 parts by weight based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms.
The pressure-sensitive adhesive composition of claim 1, wherein the acrylic copolymer having a carboxyl group contains at least one monomer selected from Chemical Formulas 6 to 9.
[Chemical Formula 6]

Wherein R ₁ is a hydrogen atom or a methyl group
(7)

(Wherein R ₁ is a hydrogen atom or a methyl group, n is an integer from 1 to 5)
[Chemical Formula 8]

(Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkyl group having 1 to 12 carbon atoms or an aryl group having 5 to 10 carbon atoms)
[Chemical Formula 9]

(Wherein R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkyl group having 1 to 12 carbon atoms or an aryl group having 5 to 10 carbon atoms)
The pressure-sensitive adhesive composition of claim 5, wherein the acrylic copolymer having a carboxyl group contains a (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms and at least one monomer selected from Formulas 6 to 9.
The pressure-sensitive adhesive composition of claim 6, wherein the at least one monomer selected from Formulas 6 to 9 contains 0.01 to 5 parts by weight based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms.
The acrylic copolymer according to claim 1, comprising 60 to 95% by weight of the acrylic copolymer having a primary alcohol group and 5 to 40 parts by weight of an acrylic copolymer having a carboxyl group;
Pressure-sensitive adhesive composition containing 0.1 to 5 parts by weight of aromatic isocyanate-based crosslinking agent and 0.01 to 0.5 parts by weight of epoxy-based crosslinking agent based on 100 parts by weight of the acrylic copolymer.