KR20140121094A

KR20140121094A - Adhesive composition

Info

Publication number: KR20140121094A
Application number: KR1020130037306A
Authority: KR
Inventors: 최한영; 유민근
Original assignee: 동우 화인켐 주식회사
Priority date: 2013-04-05
Filing date: 2013-04-05
Publication date: 2014-10-15

Abstract

The present invention relates to an adhesive composition, and more specifically, to an adhesive composition which improves heat resistance and reworkability by including an acrylic copolymer including a monomer having an alkoxysilyl group represented by chemical formula 1, and silica nanoparticles having silanol groups on the surface. In chemical formula 1, R_1 and R_2 are independently and directly connected to each other or are aliphatic hydrocarbon having 1 to 6 carbon atoms including or not including hetero atoms and R_3 is aliphatic hydrocarbon having 1 to 6 carbon atoms.

Description

[0001] ADHESIVE COMPOSITION [0002]

The present invention relates to a pressure-sensitive adhesive composition excellent in heat resistance and reworkability.

2. Description of the Related Art In recent years, with advances in the field of electronics, the size and thickness of electrical appliances have been reduced, and various properties have been required for various types of pressure-sensitive adhesives that can be used in such electrical appliances. In particular, there is a growing demand for heat resistance. This is due to the fact that the miniaturization and ultra-thinness of the electrical device leads to a significant amount of heat buildup. Various studies for releasing generated heat have also been studied, but improvement of heat resistance to various kinds of pressure-sensitive adhesives is further demanded.

The silicone pressure-sensitive adhesive is excellent in heat resistance, but is extremely expensive and not suitable for general-purpose fields, and thus a method for improving the heat resistance of a relatively inexpensive acrylic pressure-sensitive adhesive has been studied.

Specifically, a technique of introducing an alicyclic acrylic monomer has been proposed (JP-A-2008-133408). This is excellent in adhesion to a non-polar substrate such as polyolefin, but has a disadvantage that the effect of improving heat resistance is low.

Further, a technique of copolymerizing an acrylamide-based monomer or the like has been proposed (JP-A-2008-308548). This is excellent in reworkability, but it has a heat resistance temperature of up to about 120 캜, which shows a somewhat insufficient heat resistance in the field of electronics.

Further, a technique of introducing an organic-inorganic hybrid polymer has been proposed (Korean Patent Publication No. 2011-0089832). However, it has a disadvantage in that it is difficult to apply it to an electronic engineering field which performs a high temperature treatment process of 250 DEG C or more.

It is an object of the present invention to provide a pressure-sensitive adhesive composition having heat resistance to such an extent that it can be applied to a high-temperature treatment process at 250 ° C or higher.

In order to achieve the above object, the present invention provides a pressure-sensitive adhesive composition comprising an acrylic copolymer containing a monomer having an alkoxysilyl group of the following formula (1) and silica nanoparticles having a silanol group on the surface thereof.

(Wherein R ₁ and R ₂ are each independently a direct bond or an aliphatic hydrocarbon having 1 to 6 carbon atoms, which may or may not contain a hetero atom, and R ₃ is an aliphatic hydrocarbon having 1 to 6 carbon atoms).

Preferably, the monomer having an alkoxysilyl group of the formula (1) may be at least one selected from the group consisting of the following formulas (2) to (5).

The acrylic copolymer may contain a (meth) acrylate monomer having an alkyl group of 1-12 carbon atoms and a monomer having an alkoxysilyl group of the general formula (1).

The alkoxysilyl group-containing monomer of Formula 1 may be contained in an amount of 1 to 20 parts by weight based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 1-12 carbon atoms.

The acrylic copolymer includes a monomer having a hydroxyl group; Or a monomer having a carboxylic acid group and a vinyl group.

The monomer having a hydroxy group may be at least one monomer selected from the group consisting of 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-deoxybutyl (meth) acrylate, Acrylate, 2-hydroxypropyleneglycol (meth) acrylate, hydroxyalkylene glycol (meth) acrylate having 2 to 4 carbon atoms in the alkylene group, (Meth) acrylate, 4-hydroxybutyl vinyl ether, 5-hydroxypentyl vinyl ether, 6-hydroxyhexyl vinyl ether, 7-hydroxyheptyl vinyl ether, 8-hydroxyoctyl vinyl ether, Nonyl vinyl ether, and 10-hydroxydecyl vinyl ether.

The monomer having a carboxylic acid group and a vinyl group may be at least one selected from the group consisting of the following formulas (6) to (14).

The silica nanoparticles having a silanol group on the surface have an average particle diameter of 1 to 100 nm; and may be colloidal silica having a pH of 2 to 4 or 8 to 10.

The silica nanoparticles having a silanol group on the surface may contain 5 to 30 parts by weight based on 100 parts by weight of the acrylic copolymer.

The pressure-sensitive adhesive composition may further contain a crosslinking agent.

The pressure-sensitive adhesive composition according to the present invention is excellent in heat resistance due to the covalent bonding of the acrylic copolymer and the silica nanoparticles and the increase of the glass transition temperature.

In addition, the pressure-sensitive adhesive composition according to the present invention does not excessively increase the pressure-sensitive adhesive even under high temperature or high temperature and high humidity, and has an advantage that the pressure-sensitive adhesive is not left on the base material (reworking property).

The present invention relates to a pressure-sensitive adhesive composition excellent in heat resistance.

Hereinafter, the present invention will be described in detail.

The pressure-sensitive adhesive composition of the present invention contains an acrylic copolymer containing a monomer having an alkoxysilyl group of the following formula (1) and silica nanoparticles having a silanol group on the surface thereof.

[Chemical Formula 1]

Preferably, the monomer having an alkoxysilyl group of the formula (1) may be at least one selected from the group consisting of the following formulas (2) to (5). The compounds of formulas (2) to (5) may be synthesized or commercially available products. Commercially available products include SIS6990.0, SIS0489.0, SIS6993.0, and SIS0184.0 products from Gelest.

(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

In the present invention, the acrylic copolymer and the silica nanoparticle form a covalent bond together with the physical interaction of the acrylic copolymer and the silica nanoparticle, and the bonding between the acrylic copolymer and the silica nanoparticle becomes stronger, The heat resistance of the pressure-sensitive adhesive is improved by the increase of the pyrolysis initiation temperature against the condition.

The acrylic copolymer of the present invention preferably contains a (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms and a monomer having an alkoxysilyl group of the above formula (1). Here, (meth) acrylate means acrylate and methacrylate.

Examples of the alkyl (meth) acrylate monomer having 4 to 12 carbon atoms include (meth) acrylates derived from aliphatic alcohols having 4 to 12 carbon atoms such as n-butyl (meth) acrylate, Octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isopropyl (meth) acrylate, (Meth) acrylate, etc. These may be used alone or in combination of two or more. Of these, n-butyl acrylate, 2-ethylhexyl acrylate or a mixture thereof is preferable.

The alkoxysilyl group-containing monomer of Formula 1 is preferably contained in an amount of 1 to 20 parts by weight, more preferably 5 to 15 parts by weight, per 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms good. If the content is less than 1 part by weight, the effect of improving the heat resistance is insignificant. If the content is more than 20 parts by weight, the adhesive property may be deteriorated.

Further, the acrylic copolymer of the present invention comprises a monomer having a hydroxy group; Or a polymerizable monomer having a crosslinkable functional group such as a monomer having a carboxylic acid group and a vinyl group. The polymerizable monomer acts to impart cohesive strength or cohesive strength by chemical bonding with the following cross-linking agent.

[Chemical Formula 6]

(7)

[Chemical Formula 8]

[Chemical Formula 9]

[Chemical formula 10]

(11)

[Chemical Formula 12]

[Chemical Formula 13]

[Chemical Formula 14]

In particular, the monomer having a carboxylic acid group and a vinyl group is advantageous in terms of improving the adhesive strength and curing rate.

The polymerizable monomer is preferably contained in an amount of 0.05 to 10 parts by weight, more preferably 0.1 to 8 parts by weight, based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms. When the content is less than 0.05 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 lower the adhesive strength and cause durability problems.

In addition, other polymerizable monomers other than the above-mentioned monomers may be further added in an amount not lowering the adhesive force, for example, 10 parts by weight or less based on 100 parts by weight of the total monomers used in the production of the acrylic copolymer.

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 copolymer preferably has a weight average molecular weight (polystyrene conversion, Mw) of 50,000 to 2,000,000, preferably 400,000 to 2,000,000 as measured by gel permeation chromatography (GPC). If 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 diluting solvent may be required in order to ensure fairness in coating.

The silica nanoparticles of the present invention have a silanol group on the surface thereof and are covalently bonded to the acrylic copolymer. Such silica nanoparticles include colloidal silica particles.

The above-mentioned silica nanoparticles preferably have an average particle diameter of 1 to 100 nm, preferably 1 to 70 nm, and more preferably 1 to 40 nm. If the particle diameter is less than 1 nm, the tackiness and heat resistance may be deteriorated. If the particle diameter exceeds 100 nm, the haze may increase and the transparency may be deteriorated.

It is preferable that the silica nanoparticles having a silanol group on the surface are contained in an amount of 5 to 30 parts by weight, preferably 10 to 20 parts by weight, based on 100 parts by weight of the acrylic copolymer. When the content is less than 5 parts by weight, the effect of improving the heat resistance may be insufficient. When the content is more than 30 parts by weight, problems other than the heat resistance may occur.

The crosslinking agent can improve the adhesion and durability, and can maintain the reliability at a high temperature and the shape of the pressure-sensitive adhesive.

The cross-linking agent may be an isocyanate-based, epoxy-based, melamine-based, peroxide-based, metal chelating-based, oxazoline-based, or the like. Preferred is a double isocyanate-based or epoxy-based.

Examples of the isocyanate-based isocyanate include isocyanate-based compounds such as tolylene diisocyanate, xylene diisocyanate, 2,4-diphenylmethane diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tetramethyl xylene diisocyanate, Diisocyanate compounds such as isocyanate; An adduct obtained by reacting 3 moles of a diisocyanate compound with 1 mole of a polyhydric alcohol compound such as trimethylolpropane, an isocyanurate compound in which 3 moles of a diisocyanate compound is self-condensed, a diisocyanate obtained from 2 moles of 3 moles of a diisocyanate compound And multifunctional isocyanate compounds containing three functional groups such as burette, triphenylmethane triisocyanate and methylene bistriisocyanate in which the remaining one mole of diisocyanate is condensed in urea.

The epoxy system may be an ethylene glycol diglycidyl ether, a diethylene glycol diglycidyl ether, a polyethylene glycol diglycidyl ether, a propylene glycol diglycidyl ether, a tripropylene glycol diglycidyl ether, a polypropylene glycol di Hexanediol diglycidyl ether, polytetramethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, diethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, Glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, resorcinol diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, trimethylol propane triglycidyl ether, pentaerythritol poly Glycidyl ether, sorbitol polyglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, tris (glycidyl) isocyanurate N, N, N ', N'-tetraglycidyl-m-hexyldicyclohexyl) isocyanurate, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane, Xylylenediamine, and the like.

Examples of the melamine type include hexamethylol melamine, hexamethoxymethyl melamine, and hexabutoxymethyl melamine.

Such a crosslinking agent may be contained in an amount of 0.1 to 15 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the acrylic copolymer. If the content is less than 0.1 part by weight, the cohesive strength may be decreased due to insufficient crosslinking, which may deteriorate the durability of the adhesive durability and the cutability. If the content is more than 15 parts by weight, the residual stress due to the excessive crosslinking reaction may be deteriorated.

In addition, the pressure-sensitive adhesive composition of the present invention may further comprise a silane coupling agent.

The kind of the silane coupling agent is not particularly limited, and examples thereof include vinylchlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3- 3-glycidoxypropyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, Acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropyltrimethoxysilane , N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) Methyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3- Dimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatepropyltriethoxysilane, and the like. These may be used alone or in combination of two or more.

The silane coupling agent may be contained in an amount of 0 to 10 parts by weight, preferably 0.005 to 5 parts by weight, based on 100 parts by weight of the copolymer based on the solid content. If the content exceeds 10 parts by weight, the durability may be lowered.

In addition to the above components, the pressure-sensitive adhesive composition may further contain additives such as a tackifier resin, an antioxidant, a leveling agent, a surface lubricant, a dye, a pigment, a defoaming agent, A filler, a light stabilizer, and the like.

Such an additive can appropriately control the content within a range that does not impair the effect of the present invention.

The pressure-sensitive adhesive composition of the present invention can be used particularly as a pressure-sensitive adhesive for a polarizing plate or a pressure-sensitive adhesive for a surface protective film for bonding with a liquid crystal cell. In addition, it can be used not only as a protective film, a reflective sheet, a structural adhesive sheet, a photographic adhesive sheet, a lane marking adhesive sheet, an optical adhesive product, an electronic component adhesive, but also a general commercial adhesive sheet product or a medical patch.

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 One

To a 1 L reactor equipped with a cooling device for regulating the temperature of the reflux of nitrogen gas, 92 parts by weight of n-butyl acrylate (BA)

, Gelest Co., Ltd., product of SIS 6990.0), 2 parts by weight of acrylic acid (AA) and 1 part by weight of hydroxyethyl acrylate (HEA), and then 100 parts by weight of ethyl acetate was added as a solvent. Nitrogen gas was then purged for 1 hour to remove oxygen and then maintained at 70 ° C. After the mixture was homogeneously mixed, 0.07 part by weight of azobisisobutyronitrile (AIBN) was added as a reaction initiator and reacted for 6 hours to prepare an acrylic copolymer (weight average molecular weight: about 1,000,000).

Manufacturing example 2

Prepared in the same manner as in Preparation Example 1, except that 87 parts by weight of n-butyl acrylate (BA)

10 parts by weight of carboxyethyl acrylate (CEA) and 1 part by weight of 4-hydroxybutyl acrylate (4-HBA) were used to prepare an acrylic copolymer (weight Average molecular weight of about 1,000,000).

Manufacturing example 3

(Preparation Example 1), except that 82 parts by weight of n-butyl acrylate (BA)

, Gelest Co., Ltd., SIS 6990.0) 15 parts by weight, the formula 9

), And 1 part by weight of 4-hydroxybutyl vinyl ether was used to prepare an acrylic copolymer (weight average molecular weight: about 1,000,000).

Manufacturing example 4

The procedure of Preparation Example 2 was repeated except that the compound of Formula 3

, Gelest, product of SIS0489.0) was used to prepare an acrylic copolymer (weight average molecular weight: about 1,000,000).

Manufacturing example 5

The procedure of Preparation Example 2 was repeated except that the compound of Formula 5

, Gelest, product of SIS0184.0) was used to prepare an acrylic copolymer (weight average molecular weight: about 1,000,000).

compare Manufacturing example One

Except that a monomer mixture composed of 97 parts by weight of n-butyl acrylate (BA), 2 parts by weight of acrylic acid (AA) and 1 part by weight of hydroxyethyl acrylate (HEA) was prepared in the same manner as in Preparation Example 1, (Weight average molecular weight: about 1,000,000).

compare Manufacturing example 2

Except that 87 parts by weight of n-butyl acrylate (BA), 10 parts by weight of acrylic silane compound (Shin-Etsu, KBM-5103), 2 parts by weight of acrylic acid (AA) (HEA) was used to prepare an acrylic copolymer (weight average molecular weight: about 1,000,000).

Example 1 to 10 and Comparative Example 1 to 3

The acrylic copolymer, silica nanoparticle, crosslinking agent and silane coupling agent of Preparation Example 1 were mixed in the composition shown in Table 1, and then diluted to a concentration of 14% by weight to prepare a pressure-sensitive adhesive composition.

division
(Parts by weight) Acrylic copolymer
(100 parts by weight) Silica nanoparticles Cross-linking agent Silane
Coupling agent Manufacturing example Comparative Manufacturing Example A-1 A-2 A-3 B-1 B-2 Example 1 Production Example 1 - 10 - - 0.5 - 0.5 Example 2 Production Example 2 - 10 - - 0.5 - 0.5 Example 3 Production Example 3 - 10 - - 0.5 - 0.5 Example 4 Production Example 4 - 10 - - 0.5 - 0.5 Example 5 Production Example 5 - 10 - - 0.5 - 0.5 Example 6 Production Example 1 - 10 - - - 0.5 0.5 Example 7 Production Example 1 - 10 - - - - 0.5 Example 8 Production Example 1 - 10 - - - - 0.5 Example 9 Production Example 1 - 20 - - 0.5 - 0.5 Example 10 Production Example 1 - 30 - - 0.5 - 0.5 Comparative Example 1 - Comparative Preparation Example 1 10 - - 0.5 - 0.5 Comparative Example 2 - Comparative Production Example 2 10 - - 0.5 - 0.5 Comparative Example 3 Production Example 1 - - 10 - 0.5 - 0.5 A-1: Silica nanoparticles having a silanol group on the surface (Catalystable product, product of ELCOM V8802)
A-2: Silica nanoparticles having an acrylic group on the surface (MIBK-SD of Nissan Chemical Co.)
B-1: Coronate-L (TMP adduct of TDI, Urethane Japan)
B-2: Coronate-HXR (isocyanurate of HDI, Urethane Company of Japan)
Silane coupling agent: glycidoxypropyltrimethoxysilane (Shin-Etsu, KBM403)

The pressure-sensitive adhesive composition prepared above was applied on a release film coated with silicone release agent to a thickness of 25 탆 and dried at 100 캜 for 1 minute to form an adhesive layer.

The pressure-sensitive adhesive layer prepared above was laminated to an iodine-based polarizing plate having a thickness of 185 μm by pressure-sensitive adhesive processing to produce a polarizer with a pressure-sensitive adhesive. The prepared polarizing plate was stored for a curing period under the conditions of 23 캜 and 60% RH.

Test Example

The physical properties of the polarizer with a pressure-sensitive adhesive prepared in the above Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 2 below.

1. Heat resistance

The polarizing plate with a pressure-sensitive adhesive was cut into a size of 90 mm x 170 mm and the release film was peeled off. The polarizing plate was attached to both sides of a glass substrate (110 mm x 190 mm x 0.7 mm) such that the absorption axes of the respective polarizing plates were orthogonal. At this time, the applied pressure was 5 kg / cm ² , and a clean room operation was performed so that bubbles or foreign matter would not be generated.

The heat resistance of the specimen was maintained at a temperature of 80 ° C for 1000 hours, and then the occurrence of bubbles or peeling was observed. The specimens were allowed to stand at room temperature for 24 hours immediately before evaluating the state of the specimens. In addition, the moisture resistance of the specimen was measured for 1000 hours under the conditions of a temperature of 60 ° C and a humidity of 90% RH, and then the occurrence of bubbles or peeling was observed.

Bubbles or peeling can not be confirmed with the naked eye: ○

Bubbles are generated but less than 3, peeling is confirmed but less than 1 mm occurs: △

More than 3 bubbles are found or 1mm or more is exfoliated: x

2. Re-workability

The polarizing plate was cut to a size of 25 mm in width and 100 mm in length, and the release film was peeled off. The release film was then laminated on Corning's # 1737 glass at a pressure of 0.25 MPa and autoclaved for 20 minutes under conditions of 5 atm and 50 캜 Evaluation samples were prepared. After putting it in an oven at 80 ° C, which was a heat-resistant condition, it was taken out after 10 hours, left at room temperature for 120 hours, and peeled at a rate of 1.3 cm / s.

- There is no residual adhesive on the glass substrate and it is peeled off without tearing of polarizer: ⓞ

- Peel off without tearing of polarizer, but slight haze is visible on glue surface: ○

- Adhesive is left on the panel or the polarizer is torn in the process of peeling: x

division Heat resistance Re-workability Example 1 ○ Ⓞ Example 2 ○ Ⓞ Example 3 ○ Ⓞ Example 4 ○ Ⓞ Example 5 ○ Ⓞ Example 6 ○ Ⓞ Example 7 ○ Ⓞ Example 8 ○ Ⓞ Example 9 ○ Ⓞ Example 10 ○ Ⓞ Comparative Example 1 △ ○ Comparative Example 2 △ ○ Comparative Example 3 × ×

As shown in Table 2, the pressure-sensitive adhesive compositions of Examples 1 to 10 containing an acrylic copolymer containing a monomer having a specific alkoxysilyl group and a silica nanoparticle having a silanol group on the surface thereof according to the present invention were compared with Comparative Examples 1 to 3 It was confirmed that the heat resistance and the workability were excellent.

Claims

A pressure-sensitive adhesive composition comprising an acrylic copolymer containing a monomer having an alkoxysilyl group of the following formula (1) and silica nanoparticles having a silanol group on the surface:
[Chemical Formula 1]

The pressure-sensitive adhesive composition according to claim 1, wherein the alkoxysilyl group-containing monomer of Formula 1 is at least one selected from the group consisting of the following Formulas 2 to 5:
(2)

(3)

[Chemical Formula 4]

[Chemical Formula 5]

The pressure-sensitive adhesive composition according to claim 1, wherein the acrylic copolymer contains a (meth) acrylate monomer having an alkyl group of 4-12 carbon atoms and a monomer having an alkoxysilyl group of the general formula (1).

[4] The pressure-sensitive adhesive composition according to claim 3, wherein the alkoxysilyl group-containing monomer of Formula 1 contains 1 to 20 parts by weight per 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 4-12 carbon atoms.

[4] The method according to claim 3, wherein the acrylic copolymer comprises a monomer having a hydroxyl group; Or a monomer having a carboxylic acid group and a vinyl group.

[6] The method of claim 5, wherein the monomer having a hydroxyl group is at least one selected from the group consisting of 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-deoxybutyl (meth) (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxyethyleneglycol (meth) acrylate, 2-hydroxypropyleneglycol (Meth) acrylate, 4-hydroxybutyl vinyl ether, 5-hydroxypentyl vinyl ether, 6-hydroxyhexyl vinyl ether, 7-hydroxyheptyl vinyl ether, 8-hydroxyoctyl vinyl ether , 9-hydroxynonyl vinyl ether, and 10-hydroxydecyl vinyl ether.

The pressure-sensitive adhesive composition according to claim 5, wherein the monomer having a carboxylic acid group and a vinyl group is at least one selected from the group consisting of the following formulas (6) to (14):
[Chemical Formula 6]

(7)

[Chemical Formula 8]

[Chemical Formula 9]

[Chemical formula 10]

(11)

[Chemical Formula 12]

[Chemical Formula 13]

[Chemical Formula 14]

The pressure-sensitive adhesive composition according to claim 1, wherein the silica nanoparticles having a silanol group on the surface have an average particle diameter of 1 to 100 nm.

The pressure-sensitive adhesive composition according to claim 1, wherein the silica nanoparticles having a silanol group on the surface contain 5 to 30 parts by weight per 100 parts by weight of the acrylic copolymer.

The pressure-sensitive adhesive composition according to claim 1, wherein the pressure-sensitive adhesive composition further comprises a crosslinking agent.