Adhesive composition, adhesive sheet, optical film, and image display device

Abstract

To provide an adhesive composition enabling formation of an adhesive layer having improved durability, an adhesive sheet containing an adhesive layer formed with the adhesive composition, and an optical film produced from the adhesive sheet.SOLUTION: An adhesive composition according to an embodiment of the present invention comprises an acrylic copolymer, a crosslinking agent, an alkylene oxide group-containing (meth)acrylate compound, and an ionic antistatic agent having an imidazolium cation and a bis(fluorosulfonyl)imide anion. An adhesive layer formed from the adhesive composition exhibits high adhesion to a substrate film and can provide an optical film with improved reworkability even after prolonged exposure to harsh conditions including high temperature and high humidity.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an adhesive composition, an adhesive sheet, an optical film, and an image display device.

Background Art

[0002] An adhesive or an adhesive sheet can be used to bond a display panel of an image display device such as a liquid crystal display (LCD) device or an organic light emitting display (OLED) device to various optical structures or circuit structures. The adhesive needs to have improved transparency and high adhesive strength so as not to deteriorate the optical characteristics of the image display device.

[0003] In recent years, displays having high reliability even under severe conditions of high temperature and high humidity or external physical impact have been actively studied. Accordingly, structures coupled to the display also need to be formed so as to prevent the structures from falling off or peeling even under severe conditions or external impact.

[0004] Therefore, there is a need for an adhesive or an adhesive sheet having high adhesive strength and durability and capable of bonding the display structure.

Summary of the Invention

Problems to be Solved by the Invention

[0005] One problem of the present invention is to provide an adhesive composition capable of forming an adhesive layer having improved durability.

[0006] One problem of the present invention is to provide an adhesive sheet including an adhesive layer formed using the adhesive composition, and an optical film manufactured from the adhesive sheet.

Means for Solving the Problems

[0007] 1. An adhesive composition comprising an acrylic copolymer, a crosslinking agent, an alkylene oxide group-containing (meth)acrylate compound, and an ionic antistatic agent having an imidazolium cation and a bisfluorosulfonylimide anion.

[0008] 2. The adhesive composition according to item 1 above, wherein the ionic antistatic agent contains an ionic compound represented by the following chemical formula 1.

Chemical formula

[0009] 3. The adhesive composition according to item 1 above, wherein the melting point of the ionic antistatic agent is 23°C or higher.

[0010] 4. The adhesive composition according to item 1 above, wherein the content of the ionic antistatic agent is 0.01 to 7 parts by weight based on 100 parts by weight of the acrylic copolymer.

[0011] 5. The adhesive composition according to item 1 above, wherein the alkylene oxide group-containing (meth)acrylate compound is represented by the following chemical formula 2.

Chemical formula

[0012] 6. The adhesive composition according to item 5 above, wherein in the chemical formula 2, R b is an alkylene group having 1 to 3 carbon atoms, and R c is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 15 carbon atoms.

[0013] 7. In the above item 1, the content of the alkylene oxide group-containing (meth)acrylate compound is 0.1 to 5 parts by weight with respect to 100 parts by weight of the acrylic copolymer, the pressure-sensitive adhesive composition.

[0014] 8. In the above item 1, the acrylic copolymer is formed from a polymerizable mixture containing an alkyl (meth)acrylate monomer, an aromatic group-containing (meth)acrylate monomer, and a polar functional group-containing crosslinkable monomer, the pressure-sensitive adhesive composition.

[0015] 9. In the above item 8, the alkyl (meth)acrylate monomer includes a first monomer that is an alkyl (meth)acrylate monomer having 1 to 3 carbon atoms and a second monomer that is an alkyl (meth)acrylate monomer having 4 to 12 carbon atoms, the pressure-sensitive adhesive composition.

[0016] 10. In the above item 8, the polar functional group of the polar functional group-containing crosslinkable monomer includes at least one of a carboxy group, a hydroxy group, an amide group, and an amine group, the pressure-sensitive adhesive composition.

[0017] 11. In the above item 1, the crosslinking agent includes a non-yellowing type isocyanate-based crosslinking agent, the pressure-sensitive adhesive composition.

[0018] 12. In the above item 1, the content of the crosslinking agent is 0.1 part by weight to 3 parts by weight with respect to 100 parts by weight of the acrylic copolymer, the pressure-sensitive adhesive composition.

[0019] 13. In the above item 1, the pressure-sensitive adhesive composition further includes a silane-based compound having an oxygen-containing heterocyclic ring.

[0020] 14. In the above item 13, the content of the silane-based compound is 0.01 part by weight to 3 parts by weight with respect to 100 parts by weight of the acrylic copolymer, the pressure-sensitive adhesive composition.

[0021] 15. A pressure-sensitive adhesive sheet including a base film and a pressure-sensitive adhesive layer disposed on the base film and formed using the pressure-sensitive adhesive composition according to the above item 1.

[0022] 16. In Item 15 above, the surface resistivity value of the adhesive layer is 1×10 11 Ω / sq or less. An adhesive sheet.

[0023] 17. An optical film including a base film, an adhesive layer disposed on the upper surface of the base film and formed using the adhesive composition according to Item 1, and an antireflection layer disposed on the lower surface of the base film.

[0024] 18. An image display device including the optical film according to Item 17.

Advantages of the Invention

[0025] From the adhesive composition according to an exemplary embodiment of the present invention, an adhesive layer having improved adhesive strength can be formed. Further, from the adhesive composition, an adhesive layer having a low surface resistivity value can be realized.

[0026] The adhesive sheet according to an exemplary embodiment of the present invention can have improved adhesive strength and adhesion. Further, the adhesive sheet can be peeled off without leaving residues on the surface of the adherend even when it is attached to the adherend and left for a long time in a harsh environment of high temperature and / or high humidity.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0028] The pressure-sensitive adhesive composition according to an embodiment of the present invention includes an acrylic copolymer, a crosslinking agent, an alkylene oxide group-containing compound, and an ionic antistatic agent having a long-chain alkyl group. Further, according to an embodiment of the present invention, there are provided a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition and an optical film.

[0029] Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings. However, these are merely exemplary and do not limit the present disclosure to the specific embodiments illustrated.

[0030] The pressure-sensitive adhesive composition according to an exemplary embodiment includes an ionic antistatic agent. The ionic antistatic agent has an imidazolium-based cation and a bis(fluorosulfonyl)imide anion. The ionic antistatic agent can include an ionic compound having an imidazolium-based cation and a bis(fluorosulfonyl)imide anion. The ionic antistatic agent can impart ionic conductivity to a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition.

[0031] By including the ionic compound as the ionic antistatic agent, the stability over time of the pressure-sensitive adhesive composition and the durability of the pressure-sensitive adhesive layer can be improved. Further, the ionic solid has high compatibility and can maintain high transparency of the pressure-sensitive adhesive composition.

[0032] The ionic compound may be solid at room temperature. Thereby, the handling of the ionic compound and the pressure-sensitive adhesive composition containing the same can be facilitated. Further, the bleeding phenomenon of a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing a liquid ionic compound can be reduced, and contamination of an adherend can be prevented.

[0033] In an exemplary embodiment, the melting point of the ionic antistatic agent may be 23°C or higher. In some embodiments, the melting point of the ionic antistatic agent may be 23°C to 70°C. In this case, the mobility of the ionic antistatic agent in the adhesive layer in a normal temperature environment can be reduced. Thereby, the ionic antistatic agent does not elute to the end of the adhesive layer, and contamination of the adherend can be prevented.

[0034] The ionic antistatic agent may include a long-chain alkyl group bonded to a cationic nitrogen of an imidazolium skeleton. Thereby, it is possible to prevent the ionic antistatic agent from eluting from the adhesive layer as an ionic solid at normal temperature.

[0035] In some embodiments, the ionic antistatic agent may include an ionic compound represented by the following Chemical Formula 1.

[0036] [Chemical Formula]

[0037] In Chemical Formula 1, R1 may be hydrogen or a methyl group. For example, R1 may be a methyl group.

[0038] In Chemical Formula 1, R2 may be an alkyl group having 10 to 30 carbon atoms. For example, R2 may be an alkyl group having 12 to 28 carbon atoms, an alkyl group having 12 to 18 carbon atoms, or an alkyl group having 13 to 17 carbon atoms.

[0039] According to an exemplary embodiment, R2 may be a linear alkyl group having 12 to 18 carbon atoms. The ionic antistatic agent may include, for example, 1-dodecyl-3-methylimidazolium, 1-tetradecyl-3-methylimidazolium, 1-octadecyl-3-methylimidazolium, etc. as the imidazolium-based cation. These can be used alone or in combination of two or more.

[0040] In an exemplary embodiment, the content of the ionic antistatic agent may be 0.01 to 7 parts by weight with respect to 100 parts by weight of the acrylic copolymer. In some embodiments, the content of the ionic antistatic agent may be 0.01 to 5 parts by weight, 0.1 to 4.5 parts by weight, 1 to 4 parts by weight, 1.5 to 3.5 parts by weight, or 2 to 3 parts by weight with respect to 100 parts by weight of the acrylic copolymer.

[0041] Within the above range, the antistatic property of the pressure-sensitive adhesive layer can be improved while maintaining excellent durability of the pressure-sensitive adhesive layer.

[0042] The pressure-sensitive adhesive composition according to an exemplary embodiment may include an alkylene oxide group-containing (meth)acrylate compound. The alkylene oxide group-containing (meth)acrylate compound can prevent an excessive increase in the adhesive strength of the pressure-sensitive adhesive sheet at high temperatures, thereby improving the reworkability of the pressure-sensitive adhesive sheet.

[0043] The alkylene oxide group can mean an alkylene group bonded to oxygen. The alkylene oxide group-containing (meth)acrylate compound can contain at least one alkylene oxide group. For example, the alkylene oxide group-containing (meth)acrylate compound can contain a polyalkylene oxide group.

[0044] The alkylene oxide group-containing (meth)acrylate compound can be represented by the following Chemical Formula 2.

[0045] [Chemical Formula]

[0046] In Chemical Formula 2, R a may be hydrogen or a methyl group.

[0047] In Chemical Formula 2, R bmay be an alkylene group having 1 to 10 carbon atoms. In some embodiments, the above-mentioned R b may be an alkylene group having 1 to 3 carbon atoms. The "alkylene group" refers to a linear or branched saturated aliphatic hydrocarbon chain and can be a divalent hydrocarbon group.

[0048] For example, the above-mentioned R b may be a methylene group, an ethylene group, a methylmethylene group (-CH(CH3)-), etc.

[0049] In the above Chemical Formula 2, R c may be an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 30 carbon atoms. In some embodiments, R c can be an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 15 carbon atoms.

[0050] The "alkyl group" refers to a linear or branched saturated aliphatic hydrocarbon chain and can be a monovalent hydrocarbon group. The "aryl group" may be a monovalent hydrocarbon group containing at least one aromatic ring.

[0051] For example, the above-mentioned R c may be a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a phenyl group, a biphenyl group, a naphthalene group, etc.

[0052] In the above Chemical Formula 2, n may be an integer from 1 to 25.

[0053] In some embodiments, the content of the alkylene oxide group-containing (meth)acrylate-based compound may be 0.1 part by weight to 5 parts by weight, preferably 0.3 part by weight to 3 parts by weight, and more preferably 0.5 part by weight to 2 parts by weight with respect to 100 parts by weight of the acrylic copolymer. Within the above range, the durability and reworkability of the adhesive layer formed from the adhesive composition can be improved.

[0054] The pressure-sensitive adhesive composition according to an exemplary embodiment can include an acrylic copolymer. The acrylic copolymer can include an acrylic copolymer formed from a polymerizable mixture including an alkyl (meth)acrylate monomer, an aromatic group-containing (meth)acrylate monomer, and a polar functional group-containing crosslinkable monomer.

[0055] As used herein, the term "(meth)acrylate" is used to mean including acrylate or methacrylate.

[0056] The alkyl (meth)acrylate monomer may be an alkyl (meth)acrylate monomer having 1 to 12 carbon atoms. The alkyl (meth)acrylate monomer having 1 to 12 carbon atoms can include a first alkyl (meth)acrylate monomer having 1 to 3 carbon atoms and a second alkyl (meth)acrylate monomer having 4 to 12 carbon atoms. According to an exemplary embodiment, by including both the first monomer and the second monomer in the polymerizable mixture, it is possible to prevent the occurrence of defects in the pressure-sensitive adhesive sheet even in a high-temperature and / or high-humidity environment while achieving improved adhesive strength.

[0057] The first monomer and the second monomer may each be a compound derived from an aliphatic alcohol having 1 to 12 carbon atoms.

[0058] Examples of the first monomer include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, etc., and for example, it may be methyl (meth)acrylate. These can be used alone or in combination of two or more.

[0059] In an exemplary embodiment, the content of the first monomer may be 15% by weight to 45% by weight based on the total weight of the polymerizable mixture. In some embodiments, the content of the first monomer may be 20% by weight to 40% by weight, or 25% by weight to 35% by weight based on the total weight of the polymerizable mixture. Within this range, the adhesive strength and heat resistance of the pressure-sensitive adhesive sheet can be sufficiently improved.

[0060] Examples of the second monomer 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, and the like. The second monomer may be, for example, n-butyl (meth)acrylate or 2-ethylhexyl (meth)acrylate. These can be used alone or in combination of two or more.

[0061] In an exemplary embodiment, the content of the second monomer may be 40% to 80% by weight based on the total weight of the polymerizable mixture. In some embodiments, the content of the second monomer may be 45% to 70% by weight, or 55% to 70% by weight based on the total weight of the polymerizable mixture. Within this range, it is possible to prevent the cohesive force of the pressure-sensitive adhesive composition from decreasing and the durability of the pressure-sensitive adhesive layer from decreasing, and it is possible to improve the crosslink density and the adhesive strength of the pressure-sensitive adhesive layer.

[0062] In an exemplary embodiment, the ratio of the content of the second monomer to the content of the first monomer in the total weight of the polymerizable mixture may be 1 to 3. In some embodiments, the ratio of the content of the second monomer to the content of the first monomer in the total weight of the polymerizable mixture may be 1.2 to 2.7.

[0063] Within this range, the content of the second monomer having a longer alkyl group becomes equal to or more than the content of the first monomer, whereby the heat resistance of the pressure-sensitive adhesive sheet can be improved.

[0064] According to an exemplary embodiment, the polymerizable mixture may include an aromatic group-containing (meth)acrylate monomer. Thereby, the acrylic copolymer can contain a bulky aromatic group with high heat resistance, and the durability of the pressure-sensitive adhesive sheet in a harsh environment can be improved. Further, the acrylic copolymer formed from the polymerizable mixture containing the aromatic group-containing (meth)acrylate monomer can improve the light leakage phenomenon by improving the refractive index of the pressure-sensitive adhesive composition.

[0065] According to an exemplary embodiment, the aromatic group of the aromatic group-containing (meth)acrylate monomer can include an aryl group having 6 to 20 carbon atoms. The aryl group is a hydrocarbon group containing at least one aromatic ring, and can include, for example, a phenyl group, a biphenyl group, a naphthalene group, and the like.

[0066] According to an exemplary embodiment, the aromatic group-containing (meth)acrylate monomer can include an aryloxy group having 6 to 20 carbon atoms. The aryloxy group can be meant as a group in which an aryl group is bonded to an oxygen atom. For example, the aryloxy group can include a phenoxy group, a biphenyloxy group, a naphthyloxy group, and the like.

[0067] According to an exemplary embodiment, the aromatic group-containing (meth)acrylate monomer can include a structure in which a (meth)acrylate group is bonded to an aryloxy group having 6 to 20 carbon atoms through an alkylene group linker.

[0068] According to some embodiments, the aromatic group-containing (meth)acrylate monomer can include a structure in which an aryl group having 6 to 20 carbon atoms and a (meth)acrylate group are bonded through a polyether segment. The "polyether segment" can be meant as a linker structure containing a divalent oxyalkylene repeating unit (-O-(CH2) m -).

[0069] The aromatic group-containing (meth)acrylate monomer can be represented by the following Chemical Formula 3.

[0070]

Chemical Formula

[0071] In Chemical Formula 3, Ar is an aryl group having 6 to 20 carbon atoms, R4 is an alkylene group having 1 to 5 carbon atoms, R5 is hydrogen or a methyl group, and m is an integer of 1 to 10.

[0072] Examples of the aromatic group-containing (meth)acrylate monomer include phenoxymethyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxypropyl (meth)acrylate, biphenyloxy methyl (meth)acrylate, biphenyloxyethyl (meth)acrylate, biphenyloxypropyl (meth)acrylate, phenoxyethoxyethyl (meth)acrylate, phenoxyethoxyethoxyethyl (meth)acrylate, and the like. The aromatic group-containing (meth)acrylate monomer may be, for example, phenoxyethyl (meth)acrylate. These can be used alone or in combination of two or more.

[0073] According to an exemplary embodiment, the content of the aromatic group-containing (meth)acrylate monomer may be 1% by weight to 15% by weight based on the total weight of the polymerizable mixture. According to some embodiments, the content of the aromatic group-containing (meth)acrylate monomer may be 5% by weight to 10% by weight based on the total weight of the polymerizable mixture. Within the above range, the refractive index can be controlled without reducing the adhesive physical properties, and a light compensation function for light leakage can be imparted.

[0074] The polar functional group-containing crosslinkable monomer can include a crosslinkable group capable of undergoing a polymerization reaction with the (meth)acrylate monomer to form a copolymer, and a polar functional group that can be contained in a form bonded to the copolymer chain.

[0075] The polar functional group-containing crosslinkable monomer can improve the crosslinking degree of the acrylic copolymer. Further, it can react with a crosslinking agent described later to prevent the cohesive force of the adhesive layer from being broken under high temperature / high humidity conditions and impart adhesive strength.

[0076] The polar functional group can include a carboxy group, a hydroxy group, an amide group, an amine group, and the like. In some embodiments, the polar functional group-containing crosslinkable monomer can include a carboxy group-containing crosslinkable monomer, a hydroxy group-containing crosslinkable monomer, an amide group-containing crosslinkable monomer, and / or an amine group-containing crosslinkable monomer. They can be used alone or in combination of two or more.

[0077] In one embodiment, the polar functional group-containing crosslinkable monomer can include a carboxy group-containing crosslinkable monomer and a hydroxy group-containing crosslinkable monomer.

[0078] In some embodiments, the content of the crosslinkable monomer having the polar functional group may be 0.05% by weight to 10% by weight, for example, 0.1% by weight to 3% by weight, based on the total weight of the polymerizable mixture. Within this range, the cohesive force of the adhesive composition can be ensured to improve the durability of the adhesive sheet, and the adhesive force and durability can be improved by an appropriate gel fraction of the adhesive composition.

[0079] The carboxy group-containing crosslinkable monomer and the hydroxy group-containing crosslinkable monomer each contain a carboxy group or a hydroxy group that can be contained in a form bonded to a copolymer chain, and can contain a crosslinkable group that can form a copolymer by a polymerization reaction with the (meth)acrylate monomer.

[0080] The carboxy group-containing crosslinkable monomer can play a role of imparting adhesive force to the adhesive composition. For example, since the acrylic copolymer has an acidic group derived from the carboxy group-containing monomer, the adhesion and crosslinking degree of the adhesive composition can be improved.

[0081] Examples of the carboxy group-containing crosslinkable monomer include acrylic acid, methacrylic acid, etc. These can be used alone or in combination of two or more.

[0082] The content of the carboxy group-containing crosslinkable monomer may be 0.01 wt% to 0.5 wt% based on the total weight of the polymerizable mixture. For example, the content of the carboxy group-containing crosslinkable monomer may be 0.1 wt% to 0.5 wt% based on the total weight of the polymerizable mixture.

[0083] When the content of the carboxy group-containing crosslinkable monomer is within the above range, the adhesive strength of the adhesive sheet formed from the adhesive composition can be appropriately improved, and the migration of the ionic antistatic agent to the surface of the adhesive sheet can be prevented.

[0084] When the polymerizable mixture does not contain a carboxy group-containing crosslinkable monomer, the adhesive strength, adhesion, and durability in harsh environments of the adhesive layer may decrease.

[0085] The hydroxy group-containing crosslinkable monomer can impart a highly polar hydroxy group to the acrylic copolymer. Thereby, the adhesive strength of the acrylic copolymer to a polar base material can be enhanced.

[0086] Examples of the hydroxy group-containing crosslinkable monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 2-hydroxyethylene glycol (meth)acrylate, 2-hydroxypropylene glycol (meth)acrylate, hydroxyalkylene glycol (meth)acrylate having an alkylene group with 2 to 4 carbon atoms, 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. These can be used alone or in combination of two or more.

[0087] In some embodiments, the content of the hydroxy group-containing crosslinkable monomer may be 0.5% by weight to 5% by weight based on the total weight of the polymerizable mixture. For example, the content of the hydroxy group-containing crosslinkable monomer may be 0.5% by weight to 4% by weight based on the total weight of the polymerizable mixture.

[0088] Examples of the amide group-containing crosslinkable monomer include (meth)acrylamide, N-isopropylacrylamide, N-tert-butylacrylamide, 3-hydroxypropyl (meth)acrylamide, 4-hydroxybutyl (meth)acrylamide, 6-hydroxyhexyl (meth)acrylamide, 8-hydroxyoctyl (meth)acrylamide, 2-hydroxyethylhexyl (meth)acrylamide, and the like. These can be used alone or in combination of two or more.

[0089] As the amine group-containing crosslinkable monomer, a tertiary amine group-containing crosslinkable monomer can be included. Examples of the tertiary amine group-containing crosslinkable monomer include N,N-(dimethylamino)ethyl (meth)acrylate, N,N-(diethylamino)ethyl (meth)acrylate, N,N-(dimethylamino)propyl (meth)acrylate, and the like. These can be used alone or in combination of two or more.

[0090] In some embodiments, in addition to the monomer, other polymerizable monomers known in the art can be further used within a range that does not reduce the adhesive strength. For example, the other polymerizable monomers can be further included in an amount of 10% by weight or less based on the total weight of the polymerizable mixture.

[0091] The method for producing the acrylic copolymer is not particularly limited, and methods such as bulk polymerization, solution polymerization, emulsion polymerization, or suspension polymerization commonly used in the art can be used. For example, the solution polymerization method can be used. Also, solvents, polymerization initiators, chain transfer agents for controlling the molecular weight, etc. that are commonly used during polymerization can be used.

[0092] In some embodiments, the pressure-sensitive adhesive composition contains a crosslinking agent. The crosslinking agent can play a role in improving the cohesive force, adhesion, and high-temperature reliability of the pressure-sensitive adhesive and maintaining the shape of the pressure-sensitive adhesive.

[0093] In some embodiments, the crosslinking agent may be a non-yellowing type isocyanate-based crosslinking agent. The "yellowing type isocyanate-based crosslinking agent" can mean a compound in which the carbon of phenyl is directly linked to the nitrogen atom of isocyanate among the isocyanate-based crosslinking agents. The "non-yellowing type isocyanate-based crosslinking agent" can mean the remainder excluding the yellowing type isocyanate-based crosslinking agent among the isocyanate-based crosslinking agents.

[0094] The isocyanate compound has high reactivity with polar functional groups and can have improved adhesion to a corona-discharge-treated or plasma-treated substrate film.

[0095] Examples of the isocyanate compound include diisocyanate compounds such as xylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and tetramethylxylene diisocyanate; adducts obtained by reacting 3 equivalents of a diisocyanate compound with 1 equivalent of a polyhydric alcohol compound such as trimethylolpropane, isocyanurate bodies obtained by self-condensation of 3 equivalents of a diisocyanate compound, burette bodies in which the remaining 1 equivalent of diisocyanate is condensed with diisocyanate urea obtained from 2 equivalents of 3 equivalents of a diisocyanate compound, and polyfunctional isocyanate compounds containing three functional groups such as triphenylmethane triisocyanate and methylene bis triisocyanate. These can be used alone or in combination of two or more.

[0096] In some embodiments, the content of the crosslinking agent may be 0.1 to 3 parts by weight, for example, 0.1 to 2 parts by weight, based on 100 parts by weight of the acrylic copolymer. Within this range, the chains of the acrylic copolymer can be appropriately crosslinked to improve the adhesion durability and cuttability of the pressure-sensitive adhesive layer. Also, the adhesion of the pressure-sensitive adhesive sheet to the adherend can be improved.

[0097] The pressure-sensitive adhesive composition may further contain a silane compound. The silane compound can suppress the lifting and peeling of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition by forming a covalent bond or a hydrogen bond with a functional group present on the surface of the adherend, and can improve the adhesive strength.

[0098] The silane compound may be a silane compound having an oxygen-containing heterocyclic ring. At least one ring-constituting element of the oxygen-containing heterocyclic ring is oxygen, and the remaining ring-constituting elements may be carbon.

[0099] The oxygen-containing heterocyclic ring may be a monocyclic ring such as an oxirane group, a dioxirane group, an oxetane group, a tetrahydrofuran group, a dioxolane group, an oxane group, a dioxane group, or a condensed ring such as an epoxycyclohexyl group.

[0100] The silane compound may be a trialkoxysilane compound. For example, the silane compound may include a compound represented by the following Chemical Formula 4.

[0101]

Chemical Formula

[0102] In Chemical Formula 4, R6 to R8 are each independently a methyl group, an ethyl group, a methoxy group, or an ethoxy group, L includes at least one selected from the group consisting of a divalent alkylene group having 1 to 5 carbon atoms and oxygen, and R9 may be the oxygen-containing heterocyclic ring.

[0103] In some embodiments, L may be a divalent alkylene group in which CH2 is substituted with oxygen. For example, L may be a methyleneoxypropylene group (-CH2-O-CH2CH2CH2-).

[0104] According to an exemplary embodiment, the content of the silane compound may be 0.01 part by weight to 3 parts by weight based on 100 parts by weight of the acrylic copolymer.

[0105] In some embodiments, the content of the silane coupling agent may be 0.01 part by weight to 3 parts by weight based on 100 parts by weight of the acrylic copolymer, and for example, may be 0.1 part by weight to 2 parts by weight. Within the above range, the adhesive strength and adhesion of the adhesive layer can be further improved.

[0106] <Adhesive Sheet> Hereinafter, embodiments of the present invention will be described more specifically with reference to the drawings. However, the drawings attached to this specification illustrate exemplary embodiments of the present invention and serve to assist in further understanding the technical idea of the present invention together with the detailed description of the invention. Therefore, the present invention is not construed as being limited only to the matters described in the drawings.

[0107] FIG. 1 is a schematic cross-sectional view showing an adhesive sheet according to an exemplary embodiment.

[0108] Referring to FIG. 1, an adhesive sheet according to an exemplary embodiment may include a base film 110, an adhesive layer 120 disposed on the upper surface of the base film 110, and a release film 130 disposed on the upper surface of the adhesive layer 120.

[0109] The adhesive layer 120 can be formed from the aforementioned adhesive composition. For example, the adhesive layer 120 can be formed by applying an adhesive composition containing an acrylic copolymer, a crosslinking agent, an alkylene oxide group-containing (meth)acrylate compound, and an ionic antistatic agent having an imidazolium-based cation and a bisfluorosulfonylimide anion onto the base film 110 and curing it.

[0110] In some embodiments, the base film 110 can include an acrylic resin, a cellulose resin, a polyolefin resin, a polyester resin, or the like. In this case, the transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, etc. of the base film 110 can be improved.

[0111] For example, the base film 110 may include acrylic resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, and polybutylene naphthalate; cellulose resins such as diacetyl cellulose, triacetyl cellulose, and cellulose acetate butyrate; polyolefin resins such as polyethylene, polypropylene, cycloolefin, polyolefin having a norbornene structure, and ethylene-propylene copolymer; sulfone resins; polyether-ether ketone resins; arylate resins; or a mixture of the above resins.

[0112] In one embodiment, at least one surface of the base film 110, for example, the surface on which the adhesive layer 120 is formed, can be surface-treated. For example, corona discharge treatment, plasma treatment, blasting treatment, primer treatment, etc. can be performed on one surface of the base film 110.

[0113] By the surface treatment, a carboxylic acid derivative (R-COOH) can be generated on the surface of the base film 110. The carboxyl group of the carboxylic acid derivative can react with the adhesive composition, thereby further improving the adhesion of the adhesive layer to the base film.

[0114] In one embodiment, the surface of the base film 110 may not be saponified. Since the surface of the base film used for the adhesive sheet is hydrophobic, the adhesion and adhesive strength to the adhesive may deteriorate. In this case, a pretreatment step of immersing the surface of the base film 110 in an alkaline aqueous solution for saponification, forming another coat layer between the base material and the adhesive, or subjecting the surface of the base film 110 to corona or plasma treatment can improve the adhesiveness between the base material and the adhesive.

[0115] However, when performing the saponification process or forming another coating layer, the process may become complex, resulting in a decrease in the yield and processability of the pressure-sensitive adhesive sheet. Additionally, contamination and quality degradation of the pressure-sensitive adhesive sheet may occur due to additional pretreatment or coating layer formation processes.

[0116] The pressure-sensitive adhesive composition according to the above-described embodiment can improve the adhesion of the adhesive layer 120 to the surface of the base film 110 by enhancing the affinity between the organosilicon compound having a malonyl group or an acetoacetyl group and the surface of the base film 110 and the pressure-sensitive adhesive composition. Also, it can maintain heat and moisture resistance durability and adhesive reliability under severe conditions of high temperature and high humidity, and can achieve improved reworkability even after being left for a long time under the severe conditions.

[0117] The surface resistivity value of the adhesive layer 120 may be 1×10 11 Ω / □ or less. In an exemplary embodiment, it may be 7×10 10 Ω / □ or less, or 5×10 10 Ω / □ or less.

[0118] The adhesive layer 120 can be formed by applying the above-described pressure-sensitive adhesive composition onto at least one surface of the base film 110 and drying and / or curing it. For example, the adhesive layer 120 can be formed by applying the pressure-sensitive adhesive composition onto the base film 110 by a coating method such as roll coating, gravure coating, reverse coating, spray coating, air knife coating, die coater, etc.

[0119] According to an exemplary embodiment, the gel fraction of the adhesive layer 120 may be 60% - 80%, for example, 65% - 75%. The gel fraction of the adhesive layer 120 can be calculated by the following formula 1.

[0120] [Formula 1] JPEG2025113229000008.jpg1077

[0121] In Formula 1, W1 may be the initial weight of the adhesive layer 120. W2 may be the weight measured after immersing the adhesive layer 120 in an ethyl acetate solution at room temperature for 3 days and drying it at 120°C for 24 hours.

[0122] If the gel fraction of the adhesive layer 120 is less than 60%, the durability over time and the reworkability may decrease due to a decrease in the degree of crosslinking and cohesion. If the gel fraction of the adhesive layer 120 exceeds 80%, the durability and adhesion of the adhesive layer 120 may decrease due to excessive crosslinking, and damage to the object may occur when the adhesive sheet is peeled off.

[0123] Referring to FIG. 1, the adhesive sheet may further include a release film 130 disposed on one surface of the adhesive layer 120. For example, the adhesive sheet may sequentially dispose a base film 110, an adhesive layer 120, and a release film 130.

[0124] In some embodiments, the adhesive sheet may be provided in a form in which the base film 110 and the release film 130 are attached to both sides. Referring to FIG. 2, when the adhesive sheet is used, the release film 130 can be removed from the adhesive sheet. In this case, the release film 130 is removed from the adhesive sheet, and the exposed adhesive layer 120 can be attached to an object to be adhered (for example, a display panel).

[0125] In some embodiments, the adhesive sheet may be provided in a form in which the release film 130 is attached to both sides of the adhesive layer 120.

[0126] For example, a laminate can be formed by removing the release film 130 attached to one surface of the adhesive sheet and attaching an optical base film 110 or a functional layer (for example, an antireflection layer) to the exposed surface of the adhesive layer 120.

[0127] In one embodiment, the antireflection layer may be provided as an antireflection plate attached to one surface of the optical substrate film 110, and the adhesive layer 120 of the adhesive sheet may be attached to the other surface of the optical substrate film 110.

[0128] <Optical film, Image display device> FIG. 3 is a schematic cross-sectional view for explaining an optical film according to an exemplary embodiment.

[0129] Referring to FIG. 3, the optical film may include a substrate film 110, an adhesive layer 120 disposed on one surface of the substrate film 110, and an optical functional layer 140 disposed on the other surface of the substrate film 110.

[0130] For example, in the optical film, after forming the optical functional layer 140 on one surface of the substrate film 110, an adhesive composition may be applied and cured on the other surface of the substrate film 110 to form the adhesive layer 120.

[0131] In some embodiments, the optical functional layer 140 may include an antireflection layer, a hard coat layer, a retardation layer, a polarizer, and the like. For example, the optical film may be provided as an antireflection film, a hard coat film, a window film, a retardation film, a polarizing plate, or the like according to the optical functional layer 140.

[0132] In some embodiments, the optical film may further include a release film 130 disposed on one surface of the adhesive layer 120. For example, the optical film may be provided in a form in which the substrate film 110 and the release film 130 are attached to both surfaces of the adhesive layer 120. In this case, the release film 130 formed on one surface of the adhesive layer 120 can be removed, and the exposed surface of the adhesive layer 120 can be attached to an object (for example, a display panel).

[0133] In some embodiments, when the release films 130 are attached to both sides of the adhesive layer 120, after removing one side's release film 130, the optical functional layer 140 can be attached to the exposed surface, and after removing the release film 130 remaining on the other side of the adhesive layer 120, an object (for example, a display panel) can be attached to the exposed surface.

[0134] FIG. 4 is a schematic cross-sectional view for explaining an image display device according to an exemplary embodiment.

[0135] According to an exemplary embodiment, the image display device can include a display panel 200 and an optical film disposed on the display panel 200.

[0136] In some embodiments, the image display device can include a display panel 200 and an optical film disposed on the upper surface of the display panel via an adhesive layer 120. For example, by removing the release film 130 from the optical film and attaching the exposed adhesive layer 120 to the display panel 200, an image display device can be provided.

[0137] The display panel 200 may be a liquid crystal display panel (LCD), an organic light emitting display panel (OLED), or a quantum dot light emitting display panel (QLED).

[0138] In addition to the above configuration, the image display device can further include other configurations known in the art. For example, it can further include a retardation film, a hard coat film, a protective film, a window film, a touch panel, etc. The above configurations can be attached to each other by an adhesive composition according to an exemplary embodiment.

[0139] As described above, by improving the adhesion and bonding properties between the base film 110 and the adhesive layer 120, it is possible to have improved durability and stability. Therefore, even under physical external forces such as repeated bending, or under severe conditions of high temperature and high humidity, the adhesive reliability of the image display device can be maintained for a long time, and breakage, peeling, and floating phenomena of each component can be prevented.

[0140] Also, after being left for a long time under severe conditions of high temperature and high humidity, the adhesive sheet can be peeled off without damage to the object in rework and without residue of the adhesive substance.

[0141] Hereinafter, specific examples are presented to assist in understanding the present invention. However, these examples are merely illustrative of the present invention and do not limit the scope of the appended claims. It is obvious to those skilled in the art that various changes and modifications to the examples are possible within the scope of the present invention and the scope of its technical idea, and it is natural that such variations and modifications belong to the scope of the appended claims.

[0142] Production Example 1: Production of Acrylic Copolymer (A-1) Into a 1 L reactor provided with a cooling device so that nitrogen gas is refluxed and temperature adjustment is easy, 100 parts by weight of a polymerizable mixture containing 70.8% by weight of n-butyl acrylate (BA), 20% by weight of methyl acrylate (MA), 8% by weight of phenoxyethyl acrylate (PEA), 0.2% by weight of acrylic acid (AA), and 1.0% by weight of 2-hydroxyethyl acrylate (2-HEA), and 100 parts by weight of ethyl acetate (EA) as a solvent were charged to produce a mixture. To remove oxygen, the mixture was purged with nitrogen gas for 1 hour and then the temperature was maintained at 62°C. After the mixture was uniformly stirred, 0.07 parts by weight of azobisisobutyronitrile (AIBN) was added as a polymerization initiator and reacted for 8 hours to produce an acrylic copolymer (A-1) having a weight average molecular weight of 1.51 million.

[0143] Production Examples 2 to 6 An acrylic copolymer was produced in the same manner as in Production Example 1, except that the types and contents of the monomers were adjusted as shown in Table 1 below. The monomer contents were expressed in units of weight % based on the total weight of the polymerizable mixture.

[0144] [Table 1] M-1: n-butyl acrylate M-2: methyl acrylate M-3: phenoxyethyl acrylate M-4: acrylic acid M-5: 2-hydroxyethyl acrylate

[0145] Examples 1 to 23 and Comparative Examples 1 to 4 (1) Production of the pressure-sensitive adhesive composition A mixture was produced with the components and contents as shown in Table 2 below, and then diluted with ethyl acetate to a solid content concentration of 14% by weight to produce the pressure-sensitive adhesive compositions of the examples and comparative examples. The content unit of each component in the following table is parts by weight based on 100 parts by weight of the acrylic copolymer.

[0146] (2) Production of the pressure-sensitive adhesive sheet The produced pressure-sensitive adhesive composition was applied onto a release film coated with a silicone release agent, and dried at 100 °C for 2 minutes to form a pressure-sensitive adhesive layer with a thickness of 20 μm. A polarizing plate was laminated as a base material film onto the formed pressure-sensitive adhesive layer to produce a pressure-sensitive adhesive sheet. As the polarizing plate, an iodine-based polarizing plate (thickness: 185 μm) in which a cycloolefin (COP) film subjected to corona discharge treatment was laminated on one surface of a polyvinyl alcohol (PVA) polarizer and a triacetyl cellulose (TAC) film was laminated on the other surface was used. Lamination was performed such that the surface of the corona discharge-treated COP film was in contact with the pressure-sensitive adhesive layer.

[0147] [Table 2]

[0148] (A) Acrylic copolymer A-1 to A-6: Acrylic copolymers of Production Examples 1 to 6 (B) Crosslinking agent B-1: D-110N (XDI-based crosslinking agent, manufactured by Mitsui Chemicals, Inc.) B-2: Coronate-HXR (HDI-based crosslinking agent, manufactured by Nippon Polyurethane Industry Co., Ltd.) (C) Silane-based compound C-1: KBM-403 (3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) C-2: KBE-402 (3-glycidoxypropylmethyldiethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) C-3: KBM-303 (2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) C-4: X-12-989MS (the following Chemical Formula 5, manufactured by Shin-Etsu Chemical Co., Ltd.) JPEG2025113229000011.jpg3989(D) Ionic antistatic agent D-1: Compound represented by the following Chemical Formula 1-1 (ImC12-FSI, melting point: 42°C) JPEG2025113229000012.jpg5243D-2: Compound represented by the following Chemical Formula 1-2 (ImC14-FSI, melting point: 66°C) JPEG2025113229000013.jpg5344D-3: Compound represented by the following Chemical Formula 1-3 (ImC18-FSI, melting point: 48°C) JPEG2025113229000014.jpg5243D-4: Compound represented by the following Chemical Formula 1-4 (H-ImC14-FSI, melting point: 40°C) JPEG2025113229000015.jpg5041D-5: IL-P-18-2 (1-octyl-4-methylpyridinium hexafluorophosphate, manufactured by Kyoei Chemical Co., Ltd.) D-6: Compound represented by the following Chemical Formula 6 JPEG2025113229000016.jpg5038(E) (Meth)acrylate-based compound E-1: AM-130G (methoxypolyethylene glycol #600 acrylate, n in Chemical Formula 2 is about 13, manufactured by Shin-Nakamura Chemical Co., Ltd.) E-2: M-130G (methoxypolyethylene glycol methacrylate, n in Chemical Formula 2 is approximately 13, manufactured by Shin-Nakamura Chemical Co., Ltd.) E-3: A-LEN-10 (ethoxylated -o-phenylphenol acrylate, n in Chemical Formula 2 is 1, manufactured by Shin-Nakamura Chemical Co., Ltd.) E-4: AM-30PG (methoxy tripropylene glycol acrylate, n in Chemical Formula 2 is 3, manufactured by Shin-Nakamura Chemical Co., Ltd.) E-5: n-butyl acrylate

[0149] Experimental Example (1) Evaluation of Adhesion The adhesive sheets of the examples and comparative examples were cut into a length of 25 mm × width of 100 mm. After peeling off the release film, the exposed adhesive layer was pasted onto a glass substrate (#1737, manufactured by Corning Inc.), and an autoclave treatment was performed for 20 minutes under the conditions of a temperature of 50 °C and a pressure of 5 atmospheres to prepare test pieces.

[0150] The test pieces were left standing for 24 hours under the conditions of a temperature of 23 °C and a relative humidity of 50%. Using a universal tensile testing machine (UTM, manufactured by Instron), the adhesive sheet was peeled from the glass substrate at a peeling speed of 300 mm / min and a peeling angle of 180° to measure the normal temperature adhesion.

[0151] (2) Measurement of Reworkability The adhesive sheets of the examples and comparative examples were cut into a length of 25 mm × width of 100 mm. After peeling off the release film, the exposed adhesive layer was pasted onto a glass substrate with a pressure of 0.25 MPa, and an autoclave treatment was performed for 20 minutes under the conditions of a temperature of 50 °C and a pressure of 5 atmospheres to prepare test pieces.

[0152] To measure the heat-resistant reworkability, the test pieces prepared above were taken out after being left in an oven at 80 °C for 10 hours, stored at room temperature for 120 hours, and then the adhesive layer was peeled at a speed of 1.3 cm / sec.

[0153] To measure the wet heat reworkability, the test piece prepared above was left in an oven at a temperature of 60 °C and 90% RH for 12 hours, then stored at room temperature for 120 hours, and then the adhesive layer was peeled off at a speed of 1.3 cm / sec.

[0154] <Evaluation Criteria> ○: In both heat reworkability and wet heat reworkability, there is no residue of the adhesive on the glass substrate, and the base film (TAC film) is cleanly peeled off without being torn. ×: In one or more of heat reworkability and wet heat reworkability, there is adhesive residue on the glass substrate, or the base film (TAC film) is torn during peeling.

[0155] (3) Evaluation of durability (heat resistance, wet heat resistance) The adhesive sheets of the examples and comparative examples were cut into a length of 200 mm × width of 300 mm and the release film was peeled off. Then, the exposed adhesive layer was attached to a glass substrate (210 mm × 350 mm × 0.7 mm), and an autoclave treatment (50 °C × 30 minutes, 0.5 MPa) was performed to prepare a test piece. At this time, the applied pressure was 5 kg / cm 2 and clean room work was carried out so that no bubbles or foreign matters were generated.

[0156] The evaluation of heat resistance was carried out by observing the presence or absence of bubbles and peeling after leaving the test piece at a temperature of 80 °C for 1000 hours. The evaluation of wet heat resistance was carried out by observing the presence or absence of bubbles and peeling after leaving the test piece under the conditions of 60 °C and 90% RH for 1000 hours. At this time, the test piece was left at room temperature for 24 hours immediately before evaluating the state of the test piece and then observed.

[0157] <Evaluation Criteria> ◎: No bubbles or peeling ○: Less than 5 bubbles or peeling △: 5 ≤ bubbles or peeling < 10 ×: 10 ≤ bubbles or peeling

[0158] (4) Measurement of adhesion The adhesive sheet manufactured as described above was cut into a size of 25 mm in length × 50 mm in width, and attached to a SUS304 plate via a double-sided adhesive tape (width: 25 mm, manufactured by SOOKANG) on the polarizing plate surface. Then, using an elastic rubber (neoprene rubber, manufactured by Goda), the adhesive layer surface was reciprocated 20 times in the length (25 mm) direction at a pressure of 1 MPa and a speed of 0.1 m / s. At this time, the distance that the adhesive layer was extruded on the TAC film was measured to evaluate the adhesion.

[0159] (5) Measurement of Antistatic Property The manufactured adhesive sheet was cut into a size of 200 mm in length × 300 mm in width. After peeling off the release film, the surface resistivity value of the exposed adhesive layer was measured to evaluate the antistatic property. The measurement method was to measure the surface resistivity under the conditions of 25°C, 50% RH, 500 V, and 10 seconds using a resistivity meter, Hi-Rester UP-HT450 (manufactured by Mitsubishi Chemical Analytech Co., Ltd.). The results are summarized in Table 3 below.

[0160] [Table 3]

[0161] Referring to Table 3, the adhesive sheet of the example was able to achieve improved reworkability even after being left for a long time while ensuring the adhesion to the base film. In addition, the adhesive sheet of the example had a low surface resistance and improved antistatic property, with few bubbles and peeling even in a harsh environment of high temperature and / or high humidity, and the pasted state was maintained.

[0162] On the other hand, in the adhesive sheet of the comparative example, the durability decreased or the reworkability deteriorated in a high-temperature environment.

[0163] The adhesive sheet of Comparative Example 1 was formed from a composition that does not contain an alkylene oxide group-containing compound. Therefore, when the adhesive sheet was peeled off after being attached to the adherend and left at a high temperature, residues were generated on the surface of the adherend or bubbles were generated.

[0164] The pressure-sensitive adhesive sheets of Comparative Examples 2 and 3 were formed from a composition containing an antistatic agent having an anion instead of bisfluorosulfonylimide. For this reason, the hygrothermal resistance of the pressure-sensitive adhesive sheets was greatly deteriorated.

[0165] The pressure-sensitive adhesive sheet of Comparative Example 4 was formed from a composition containing an acrylate compound having no alkylene oxide group. For this reason, the hygrothermal resistance and reworkability of the pressure-sensitive adhesive sheet were inferior to those of the Examples.

[0166] The foregoing description is merely an exemplification applying the principle of the present disclosure, and other configurations can be further included without departing from the scope of the present invention.

Explanation of Reference Numerals

[0167] 110: Substrate film 120: Adhesive layer 130: Release film 140: Optical functional layer 200: Display panel

Claims

1. An acrylic copolymer, a crosslinking agent, an alkylene oxide group-containing (meth)acrylate compound, and an ionic antistatic agent having an imidazolium cation and a bisfluorosulfonylimide anion, the pressure-sensitive adhesive composition comprising the same.

2. The pressure-sensitive adhesive composition according to claim 1, wherein the ionic antistatic agent contains an ionic compound represented by the following chemical formula 1. 【Chemical 1】 (In the above chemical formula 1, R １ is hydrogen or a methyl group, and R ２ is an alkyl group having 10 to 30 carbon atoms.)

3. The pressure-sensitive adhesive composition according to claim 1, wherein the melting point of the ionic antistatic agent is 23°C or higher.

4. The pressure-sensitive adhesive composition according to claim 1, wherein the content of the ionic antistatic agent is 0.01 part by weight to 7 parts by weight with respect to 100 parts by weight of the acrylic copolymer.

5. The pressure-sensitive adhesive composition according to claim 1, wherein the alkylene oxide group-containing (meth)acrylate compound is represented by the following chemical formula 2. 【Chemical Formula 2】 (In the above chemical formula 2, R ａ is hydrogen or a methyl group, and R ｂ is an alkylene group having 1 to 10 carbon atoms, and R ｃ is an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 30 carbon atoms, and n is an integer of 1 to 25.)

6. In the chemical formula (2), the R ｂ is an alkylene group having 1 to 3 carbon atoms, and R ｃ is an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 15 carbon atoms. The pressure-sensitive adhesive composition according to claim 5.

7. The pressure-sensitive adhesive composition according to claim 1, wherein the content of the alkylene oxide group-containing (meth)acrylate compound is 0.1 part by weight to 5 parts by weight with respect to 100 parts by weight of the acrylic copolymer.

8. The pressure-sensitive adhesive composition according to claim 1, wherein the acrylic copolymer is formed from a polymerizable mixture containing an alkyl (meth)acrylate monomer, an aromatic group-containing (meth)acrylate monomer, and a crosslinkable monomer containing a polar functional group.

9. The pressure-sensitive adhesive composition according to claim 8, wherein the alkyl (meth)acrylate monomer includes a first monomer that is an alkyl (meth)acrylate monomer having 1 to 3 carbon atoms and a second monomer that is an alkyl (meth)acrylate monomer having 4 to 12 carbon atoms.

10. The pressure-sensitive adhesive composition according to claim 8, wherein the polar functional group of the crosslinkable monomer containing a polar functional group includes at least one of a carboxy group, a hydroxy group, an amide group, and an amine group.

11. The pressure-sensitive adhesive composition according to claim 1, wherein the crosslinking agent includes a non-yellowing type isocyanate-based crosslinking agent.

12. The pressure-sensitive adhesive composition according to claim 1, wherein the content of the crosslinking agent is 0.1 part by weight to 3 parts by weight with respect to 100 parts by weight of the acrylic copolymer.

13. The pressure-sensitive adhesive composition according to claim 1, further comprising a silane compound having an oxygen-containing heterocyclic ring.

14. The pressure-sensitive adhesive composition according to claim 13, wherein the content of the silane compound is 0.01 part by weight to 3 parts by weight with respect to 100 parts by weight of the acrylic copolymer.

15. A base film, An adhesive sheet including the base film and an adhesive layer disposed on the base film and formed using the adhesive composition according to claim 1.

16. The surface resistivity value of the adhesive layer is 1 × 10 １１ Ω / sq or less. The adhesive sheet according to claim 15.

17. A base film, An adhesive layer disposed on the upper surface of the base film and formed using the adhesive composition according to claim 1, An optical film including an antireflection layer disposed on the lower surface of the base film.

18. An image display device including the optical film according to claim 17.

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