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

Abstract

The invention provides an adhesive composition, an adhesive sheet, an optical film, and an image display device. The adhesive composition according to an embodiment of the present invention comprises an acrylic copolymer, a cross-linking agent, a (meth) acrylate compound containing an alkylene oxide group, and an ionic antistatic agent having an imidazolium cation and a bis (fluorosulfonyl) imide anion. An adhesive layer formed from the adhesive composition has high adhesion to a substrate film, and can provide an optical film having improved reworkability even after long-term placement under severe conditions such as high temperature and high humidity.

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] In order 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, an adhesive or an adhesive sheet can be used. The above-mentioned adhesive needs to have improved transparency to avoid deteriorating the optical characteristics of the image display device, and at the same time have high adhesive strength.

[0003] In recent years, active research has been carried out on displays that also have high reliability under severe conditions of high temperature and high humidity or external physical impacts. Therefore, structures combined with the above-mentioned displays also need to be formed so as to prevent the structures from falling off or peeling even under severe conditions and external impacts.

[0004] Therefore, there is a need for an adhesive or an adhesive sheet that has high adhesive strength and durability and can bond the above-mentioned display structures. Summary of the Invention

[0005] Problems to be Solved

[0006] One problem of the present invention is to provide an adhesive composition capable of forming an adhesive layer having improved durability.

[0007] One problem of the present invention is to provide an adhesive sheet including an adhesive layer formed using the above-mentioned adhesive composition and an optical film manufactured from the above-mentioned adhesive sheet.

[0008] Means for Solving the Problems

[0009] 1. An adhesive composition comprising an acrylic copolymer, a crosslinking agent, an alkenyloxy group-containing (meth)acrylate compound, and an ionic antistatic agent having an imidazolium-based cation and a bis(fluorosulfonyl)imide anion.

[0010] 2. The adhesive composition according to 1 above, wherein the ionic antistatic agent includes an ionic compound represented by the following Chemical Formula 1.

[0011] [Chemical Formula 1]

[0012]

[0013] (In the above Chemical Formula 1, R1 is hydrogen or methyl, and R2 is an alkyl group having 10 to 30 carbon atoms).

[0014] 3. The adhesive composition according to 1 above, wherein the ionic antistatic agent has a melting point of 23°C or higher.

[0015] 4. The pressure-sensitive adhesive composition as described in 1 above, with respect to 100 parts by weight of the above acrylic copolymer, the content of the above ionic antistatic agent is 0.01 part by weight to 7 parts by weight.

[0016] 5. The pressure-sensitive adhesive composition as described in 1 above, the above (meth)acrylate compound containing an alkenyloxy group is represented by the following Chemical Formula 2.

[0017] [Chemical Formula 2]

[0018]

[0019] (In the above Chemical Formula 2, R a is hydrogen or methyl, R b is an alkylene group having 1 to 10 carbon atoms, 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 from 1 to 25).

[0020] 6. The pressure-sensitive adhesive composition as described in 5 above, in the above Chemical Formula 2, the above 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.

[0021] 7. The pressure-sensitive adhesive composition as described in 1 above, with respect to 100 parts by weight of the above acrylic copolymer, the content of the above (meth)acrylate compound containing an alkenyloxy group is 0.1 part by weight to 5 parts by weight.

[0022] 8. The pressure-sensitive adhesive composition as described in 1 above, the above acrylic copolymer is formed from a polymerizable mixture containing (meth)acrylate monomers, (meth)acrylate monomers containing an aromatic group, and crosslinkable monomers containing a polar functional group.

[0023] 9. The pressure-sensitive adhesive composition as described in 8 above, the above (meth)acrylate monomers include a first monomer and a second monomer, the above first monomer is a (meth)acrylate monomer having 1 to 3 carbon atoms, and the above second monomer is a (meth)acrylate monomer having 4 to 12 carbon atoms.

[0024] 10. The pressure-sensitive adhesive composition as described in 8 above, the polar functional group of the above crosslinkable monomer containing a polar functional group includes at least one of a carboxyl group, a hydroxyl group, an amide group, and an amino group.

[0025] 11. The pressure-sensitive adhesive composition as described in 1 above, the above crosslinking agent includes a non-yellowing isocyanate crosslinking agent.

[0026] 12. The adhesive composition as described in 1 above, with respect to 100 parts by weight of the above acrylic copolymer, the content of the above crosslinking agent is 0.1 part by weight to 3 parts by weight.

[0027] 13. The adhesive composition as described in 1 above, which further contains a silane compound having an oxygen-containing heterocycle.

[0028] 14. The adhesive composition as described in 13 above, with respect to 100 parts by weight of the above acrylic copolymer, the content of the above silane compound is 0.01 part by weight to 3 parts by weight.

[0029] 15. An adhesive sheet, which comprises a base film and an adhesive layer, and the above adhesive layer is disposed on the above base film and formed using the adhesive composition described in 1 above.

[0030] 16. The adhesive composition as described in 15 above, the surface resistivity value of the above adhesive layer has a value of 1×10 11 Ω / □ or less.

[0031] 17. An optical film, which comprises a base film, an adhesive layer and an antireflection layer, the above adhesive layer is disposed on the upper surface of the above base film and formed using the adhesive composition described in 1 above, and the above antireflection layer is disposed on the lower surface of the above base film.

[0032] 18. An image display device, which comprises the optical film described in 17 above.

[0033] Advantages of the Invention

[0034] With the adhesive composition of the exemplary embodiments of the present invention, an adhesive layer with improved adhesive force can be formed. In addition, with the above adhesive composition, an adhesive layer with a low surface resistivity value can be achieved.

[0035] The adhesive sheet of the exemplary embodiments of the present invention can have improved adhesive force and adhesion. In addition, after the above adhesive sheet is attached to an adherend, even when it is left for a long time in a harsh environment of high temperature and / or high humidity, it can be peeled off from the surface of the adherend without residue. Description of the Drawings

[0036] Figure 1 and Figure 2 are schematic cross-sectional views for explaining the adhesive sheet of the exemplary embodiments.

[0037] Figure 3 is a schematic cross-sectional view for explaining the optical film of the exemplary embodiments.

[0038] Figure 4 is a schematic cross-sectional view for explaining the image display device of the exemplary embodiments.

[0039] Symbol Explanation

[0040] 110: Substrate film 120: Adhesive layer

[0041] 130: Release film 140: Optical functional layer

[0042] 200: Display panel Detailed Embodiment

[0043] The adhesive composition of the embodiment of the present invention includes an acrylic copolymer, a crosslinking agent, an alkenyloxy group-containing compound, and an ionic antistatic agent having a long-chain alkyl group. In addition, according to the embodiment of the present invention, there are provided an adhesive sheet and an optical film having an adhesive layer formed of the above adhesive composition.

[0044] Hereinafter, the present disclosure will be described in detail with reference to the drawings. However, this is merely illustrative, and the present disclosure is not limited by the specific embodiments of the illustrative description.

[0045] The adhesive composition of the exemplary embodiment includes an ionic antistatic agent. The above ionic antistatic agent has an imidazolium-based cation and a bis(fluorosulfonyl)imide anion. The above ionic antistatic agent may include an ionic compound having an imidazolium-based cation and a bis(fluorosulfonyl)imide anion. The above ionic antistatic agent can impart ionic conductivity to the adhesive layer formed of the adhesive composition.

[0046] By including the above ionic compound as an ionic antistatic agent, it is possible to improve the stability of the adhesive composition over time and the durability of the adhesive layer. In addition, the ionic solid has high compatibility and can maintain the high transparency of the adhesive composition.

[0047] The above ionic compound can be a solid at room temperature. Thus, the above ionic compound and the adhesive composition containing it can be easily processed. In addition, the bleeding phenomenon of the adhesive layer formed of the adhesive composition containing a liquid ionic compound can be reduced, and the contamination of the adherend can be prevented.

[0048] In the exemplary embodiment, the melting point of the ionic antistatic agent can be 23°C or higher. In some embodiments, the melting point of the ionic antistatic agent can be 23°C to 70°C. In this case, the mobility of the ionic antistatic agent inside the adhesive layer at room temperature can be reduced. Thus, the ionic antistatic agent does not dissolve out to the end of the adhesive layer, and the contamination of the adherend can be prevented.

[0049] The above ionic antistatic agent may include a long-chain alkyl group bonded to the cationic nitrogen of the imidazolium skeleton. Thus, the ionic antistatic agent is an ionic solid at room temperature and does not dissolve out from the adhesive layer.

[0050] In some embodiments, the above-mentioned ionic antistatic agent may contain an ionic compound represented by the following Chemical Formula 1.

[0051] [Chemical Formula 1]

[0052]

[0053] In the above Chemical Formula 1, R1 may be hydrogen or methyl. For example, R1 may be methyl.

[0054] In the above 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.

[0055] According to an exemplary embodiment, the above R2 may be a straight-chain alkyl group having 12 to 18 carbon atoms. The above ionic antistatic agent may contain, for example, 1-dodecyl-3-methylimidazolium, 1-tetradecyl-3-methylimidazolium, 1-octadecyl-3-methylimidazolium, etc. as the above-mentioned imidazolium-based cations. They may be used alone or in combination of two or more.

[0056] In an exemplary embodiment, relative to 100 parts by weight of the above acrylic copolymer, the content of the above ionic antistatic agent may be 0.01 part by weight to 7 parts by weight. In some embodiments, relative to 100 parts by weight of the above acrylic copolymer, the content of the above ionic antistatic agent may be 0.01 part by weight to 5 parts by weight, 0.1 part by weight to 4.5 parts by weight, 1 part by weight to 4 parts by weight, 1.5 parts by weight to 3.5 parts by weight, or 2 parts by weight to 3 parts by weight.

[0057] Within the above range, the antistatic property of the adhesive layer can be improved, and the durability of the adhesive layer can be maintained excellently.

[0058] The adhesive composition of an exemplary embodiment may contain an (meth)acrylate compound containing an alkylene oxide group. The above (meth)acrylate compound containing an alkylene oxide group can prevent the adhesive force of the adhesive sheet from increasing excessively at high temperatures, thereby improving the reworkability of the adhesive sheet.

[0059] The meaning of the above alkylene oxide group may be an alkylene group bonded with oxygen. The above (meth)acrylate compound containing an alkylene oxide group may contain at least one alkylene oxide group. For example, the above (meth)acrylate compound containing an alkylene oxide group may contain a polyalkylene oxide.

[0060] The above (meth)acrylate compound containing an alkylene oxide group may be represented by the following Chemical Formula 2.

[0061] [Chemical Formula 2]

[0062]

[0063] In the above Chemical Formula 2, R a may be hydrogen or methyl.

[0064] In the above Chemical Formula 2, R b may be an alkylene group having 1 to 10 carbon atoms. In some embodiments, the above R b may be an alkylene group having 1 to 3 carbon atoms. The above "alkylene group" may be a divalent hydrocarbon group that is a straight-chain or branched-chain saturated aliphatic hydrocarbon chain.

[0065] For example, the above R b may be methylene, ethylene, methylmethylene (-CH(CH3)-), etc.

[0066] 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 may be an alkyl group having 1 to 3 carbon atoms or an aryl group having 6 to 15 carbon atoms.

[0067] The above "alkyl group" may be a monovalent hydrocarbon group that is a straight-chain or branched-chain saturated aliphatic hydrocarbon chain. The above "aryl group" may be a monovalent hydrocarbon group containing at least one aromatic ring.

[0068] For example, the above R c may be methyl, ethyl, n-propyl, isopropyl, phenyl, biphenyl, naphthyl, etc.

[0069] In the above Chemical Formula 2, n may be an integer from 1 to 25.

[0070] In some embodiments, relative to 100 parts by weight of the above acrylic copolymer, the content of the above (meth)acrylate compound containing an alkenyloxy group may be from 0.1 part by weight to 5 parts by weight, preferably from 0.3 part by weight to 3 parts by weight, and more preferably from 0.5 part by weight to 2 parts by weight. Within the above range, the durability and reworkability of the adhesive layer formed from the adhesive composition can be improved.

[0071] The adhesive composition of the exemplary embodiment may contain an acrylic copolymer. The above acrylic copolymer may contain an acrylic copolymer formed from a polymerizable mixture, and the above polymerizable mixture contains a (meth)acrylate monomer, a (meth)acrylate monomer containing an aromatic group, and a crosslinkable monomer containing a polar functional group.

[0072] The term “(meth)acrylate” used in this specification is used in the sense of encompassing acrylate or methacrylate.

[0073] The above-mentioned (meth)acrylic acid alkyl ester-based monomer may be a (meth)acrylic acid alkyl ester-based monomer having 1 to 12 carbon atoms. The above-mentioned (meth)acrylic acid alkyl ester-based monomer having 1 to 12 carbon atoms may include a first (meth)acrylic acid alkyl ester monomer having 1 to 3 carbon atoms and a second (meth)acrylic acid alkyl ester monomer having 4 to 12 carbon atoms. According to the exemplary embodiment, the above-mentioned polymerizable mixture contains both the first monomer and the second monomer at the same time, so that improved adhesiveness can be achieved, and defects of the adhesive sheet can be prevented even in a high-temperature and / or high-humidity environment.

[0074] Each of the above-mentioned first monomer and the above-mentioned second monomer may be a compound derived from an aliphatic alcohol having 1 to 12 carbon atoms.

[0075] Examples of the above-mentioned first monomer include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, etc. For example, it may be methyl (meth)acrylate. They may be used alone or in combination of two or more.

[0076] In the exemplary embodiment, the content of the above-mentioned first monomer in the total weight of the above-mentioned polymerizable mixture may be 15% by weight to 45% by weight. In some embodiments, the content of the above-mentioned first monomer in the total weight of the above-mentioned polymerizable mixture may be 20% by weight to 40% by weight or 25% by weight to 35% by weight. Within the above range, the adhesiveness and heat resistance of the adhesive sheet can be sufficiently improved.

[0077] Examples of the above-mentioned second monomer include n-butyl (meth)acrylate, 2-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, etc. The above-mentioned second monomer may be, for example, n-butyl (meth)acrylate or 2-ethylhexyl (meth)acrylate. They may be used alone or in combination of two or more.

[0078] In the exemplary embodiment, the content of the above-mentioned second monomer in the total weight of the above-mentioned polymerizable mixture may be 40% by weight to 80% by weight. In some embodiments, the content of the above-mentioned second monomer in the total weight of the above-mentioned polymerizable mixture may be 45% by weight to 70% by weight or 55% by weight to 70% by weight. Within the above range, a decrease in the durability of the adhesive layer due to a decrease in the cohesion of the adhesive composition can be prevented, and the crosslink density and adhesion of the adhesive layer can be improved.

[0079] In an exemplary embodiment, in the total weight of the above-described polymeric mixture, the ratio of the content of the second monomer to the content of the first monomer may be from 1 to 3. In some embodiments, in the total weight of the above-described polymeric mixture, the ratio of the content of the second monomer to the content of the first monomer may be from 1.2 to 2.7.

[0080] Within the above range, the content of the second monomer having a longer alkyl group may be equal to or greater than the content of the first monomer, whereby the heat resistance of the adhesive sheet can be improved.

[0081] According to an exemplary embodiment, the above-described polymeric mixture may include an aromatic group-containing (meth)acrylate monomer. Thereby, the acrylic copolymer may include a highly heat-resistant and bulky aromatic group, and the durability of the adhesive sheet in a harsh environment can be improved. In addition, the acrylic copolymer formed from the polymeric mixture containing the aromatic group-containing (meth)acrylate monomer can increase the refractive index of the adhesive composition, whereby the light leakage phenomenon can be improved.

[0082] According to an exemplary embodiment, the aromatic group of the above-described aromatic group-containing (meth)acrylate monomer may include an aryl group having 6 to 20 carbon atoms. The aryl group is a hydrocarbon group containing at least one aromatic ring, and for example, may include a phenyl group, a biphenyl group, a naphthyl group, etc.

[0083] According to an exemplary embodiment, the above-described aromatic group-containing (meth)acrylate monomer may include an aryloxy group having 6 to 20 carbon atoms. The aryloxy group may refer to a group formed by the bonding of an oxygen atom to an aryl group. For example, the aryloxy group may include a phenoxy group, a biphenoxy group, a naphthyloxy group, etc.

[0084] According to an exemplary embodiment, the above-described aromatic group-containing (meth)acrylate monomer may include a structure in which a (meth)acrylate group is bonded to an aryloxy group having 6 to 20 carbon atoms through an alkylene linking group.

[0085] According to some embodiments, the above-described aromatic group-containing (meth)acrylate monomer may include a structure in which an aryl group having 6 to 20 carbon atoms is bonded to a (meth)acrylate group through a polyether chain segment. The so-called "polyether chain segment" may refer to a linking group structure containing a divalent oxoalkylene repeating unit (-O-(CH2) m -).

[0086] The above-described aromatic group-containing (meth)acrylate monomer may be represented by the following Chemical Formula 3.

[0087] [Chemical Formula 3]

[0088]

[0089] In the above 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 methyl, and m is an integer of 1 to 10.

[0090] Examples of the above aromatic group-containing (meth)acrylate monomer include phenoxymethyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxypropyl (meth)acrylate, biphenoxymethyl (meth)acrylate, biphenoxyethyl (meth)acrylate, biphenoxypropyl (meth)acrylate, phenoxyethoxyethyl (meth)acrylate, phenoxyethoxyethoxyethyl (meth)acrylate, etc. The above aromatic group-containing (meth)acrylate monomer can be, for example, phenoxyethyl (meth)acrylate. They can be used alone or in combination of two or more.

[0091] According to the exemplary embodiments, the content of the above aromatic group-containing (meth)acrylate monomer in the total weight of the above polymerizable mixture can be 1 wt% to 15 wt%. According to some embodiments, the content of the above aromatic group-containing (meth)acrylate monomer in the total weight of the above polymerizable mixture can be 5 wt% to 10 wt%. Within the above range, a light compensation function against light leakage can be imparted by controlling the refractive index without reducing the adhesiveness.

[0092] The above crosslinkable monomer containing a polar functional group can include a crosslinkable group capable of undergoing a polymerization reaction with the above (meth)acrylate monomer to form a copolymer and a polar functional group capable of being included in the form of binding to the copolymer chain.

[0093] The above crosslinkable monomer containing a polar functional group can increase the crosslinking degree of the acrylic copolymer. In addition, it can prevent the cohesion of the adhesive layer from decreasing under high temperature / high humidity conditions and impart adhesive strength by reacting with a crosslinking agent described later.

[0094] The above polar functional group can include a carboxyl group, a hydroxyl group, an amide group, an amine group, etc. In some embodiments, the above crosslinkable monomer containing a polar functional group can include a crosslinkable monomer containing a carboxyl group, a crosslinkable monomer containing a hydroxyl group, a crosslinkable monomer containing an amide group, and / or a crosslinkable monomer containing an amine group. They can be used alone or in combination of two or more.

[0095] In one embodiment, the above crosslinkable monomer containing a polar functional group can include a crosslinkable monomer containing a carboxyl group and a crosslinkable monomer containing a hydroxyl group.

[0096] In some embodiments, the content of the crosslinkable monomer having a polar functional group may be 0.05% by weight to 10% by weight, for example, 0.1% by weight to 3% by weight, in the total weight of the above-mentioned polymerizable mixture. Within the above range, the cohesion of the adhesive composition can be ensured to improve the durability of the adhesive sheet, and the gel fraction of the adhesive composition is appropriate to improve the adhesive force and durability.

[0097] The above-mentioned crosslinkable monomer containing a carboxyl group and the crosslinkable monomer containing a hydroxyl group may each contain a carboxyl group or a hydroxyl group that can be included in the form of binding to the copolymer chain, and may contain a crosslinkable group capable of undergoing a polymerization reaction with the above-mentioned (meth)acrylate monomer to form a copolymer.

[0098] The above-mentioned crosslinkable monomer containing a carboxyl group can play a role in imparting adhesive force to the adhesive composition. For example, since the acrylic copolymer has an acidic group derived from the carboxyl group-containing monomer, the adhesion and crosslinking degree of the adhesive composition can be improved.

[0099] Examples of the above-mentioned crosslinkable monomer containing a carboxyl group include acrylic acid, methacrylic acid, etc. They can be used alone or in combination of two or more.

[0100] The content of the above-mentioned crosslinkable monomer containing a carboxyl group may be 0.01% by weight to 0.5% by weight in the total weight of the above-mentioned polymerizable mixture. For example, the content of the crosslinkable monomer containing a carboxyl group may be 0.1% by weight to 0.5% by weight in the total weight of the polymerizable mixture.

[0101] When the content of the crosslinkable monomer containing a carboxyl group is within the above range, the adhesive force of the adhesive sheet formed from the adhesive composition can be appropriately increased, and the above-mentioned ionic antistatic agent can be prevented from transferring to the surface of the adhesive sheet.

[0102] If the above-mentioned polymerizable mixture does not contain a crosslinkable monomer containing a carboxyl group, the adhesive force, adhesion, and durability in extreme environments of the adhesive layer may decrease.

[0103] The above-mentioned crosslinkable monomer containing a hydroxyl group can provide a hydroxyl group with a high degree of polarity to the acrylic copolymer. Therefore, the adhesive force of the acrylic copolymer to a polar substrate can be improved.

[0104] Examples of the above-mentioned hydroxyl group-containing crosslinkable monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 2-hydroxyethyleneglycol (meth)acrylate, 2-hydroxypropyleneglycol (meth)acrylate, hydroxyalkylene glycol (meth)acrylates with 2 to 4 carbon atoms in the alkylene group, 4-hydroxybutyl vinyl ether, 5-hydroxypentyl vinyl ether, 6-hydroxyhexyl vinyl ether, 7-hydroxyheptyl vinyl ether, 8-hydroxyoctyl vinyl ether, 9-hydroxynonyl vinyl ether, 10-hydroxydecyl vinyl ether, etc. They can be used alone or in combination of two or more.

[0105] In some embodiments, the content of the above-mentioned hydroxyl group-containing crosslinkable monomer in the total weight of the above-mentioned polymerizable mixture can be 0.5% by weight to 5% by weight. For example, the content of the hydroxyl group-containing crosslinkable monomer in the total weight of the polymerizable mixture can be 0.5% by weight to 4% by weight.

[0106] Examples of the above-mentioned amide group-containing crosslinkable monomers 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, etc. They can be used alone or in combination of two or more.

[0107] As the above-mentioned amine group-containing crosslinkable monomer, a crosslinkable monomer containing a tertiary amine group can be included. Examples of the above-mentioned crosslinkable monomer containing a tertiary amine group include N,N-(dimethylamino)ethyl (meth)acrylate, N,N-(diethylamino)ethyl (meth)acrylate, N,N-(dimethylamino)propyl (meth)acrylate, etc. They can be used alone or in combination of two or more.

[0108] In some embodiments, in addition to the above monomers, other polymerizable monomers well-known in the art can be further used within the range that does not reduce the adhesive strength. For example, the content of the above other polymerizable monomers in the total weight of the polymerizable mixture can be 10% by weight or less.

[0109] The method for producing the above acrylic copolymer is not particularly limited, and it can be produced by methods such as bulk polymerization, solution polymerization, emulsion polymerization, or suspension polymerization commonly used in the art. For example, it can be produced by solution polymerization. In addition, commonly used solvents, polymerization initiators, chain transfer agents for controlling the molecular weight, etc. can be used during polymerization.

[0110] In some embodiments, the above-mentioned adhesive composition contains a crosslinking agent. The above-mentioned crosslinking agent can enhance the cohesion, adhesion, and high-temperature reliability of the adhesive and maintain the shape of the adhesive.

[0111] In some embodiments, the above-mentioned crosslinking agent can be a non-yellowing isocyanate-based crosslinking agent. The yellowing isocyanate-based crosslinking agent may refer to a compound in which the nitrogen atom of the isocyanate in the isocyanate-based crosslinking agent is directly connected to the carbon of the phenyl group, and the non-yellowing isocyanate-based crosslinking agent may refer to the remaining compounds in the above-mentioned isocyanate-based crosslinking agent other than the above-mentioned yellowing isocyanate-based crosslinking agent.

[0112] The above-mentioned isocyanate-based compound can have high reactivity with polar functional groups and can have improved adhesion to a substrate film treated by corona discharge or plasma treatment.

[0113] Examples of the above-mentioned isocyanate-based compounds include: diisocyanate compounds such as xylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and tetramethylxylene diisocyanate; adducts obtained by reacting 1 equivalent of a polyol-based compound such as trimethylolpropane with 3 equivalents of a diisocyanate compound, isocyanurate bodies obtained by self-condensation of 3 equivalents of a diisocyanate compound, biuret bodies obtained by condensing diisocyanate urea obtained from 2 equivalents of 3 equivalents of a diisocyanate compound with the remaining 1 equivalent of a diisocyanate, polyfunctional isocyanate compounds having 3 functional groups such as triphenylmethane triisocyanate and methylene bis triisocyanate, etc. They can be used alone or in combination of two or more.

[0114] In some embodiments, relative to 100 parts by weight of the above-mentioned acrylic copolymer, the content of the above-mentioned crosslinking agent can be 0.1 part by weight to 3 parts by weight, for example, it can be 0.1 part by weight to 2 parts by weight. Within the above range, appropriate crosslinking can be achieved between the acrylic copolymer chains to improve the adhesion durability and cut-off property of the adhesive layer. In addition, the adhesion between the adhesive sheet and the adherend can be improved.

[0115] The above-mentioned adhesive composition may further contain a silane-based compound. The above-mentioned silane-based compound can inhibit the warping and peeling of the adhesive layer formed by the adhesive composition by forming a covalent bond or a hydrogen bond with the functional groups present on the surface of the adherend, and can improve the adhesive force.

[0116] The above-mentioned silane-based compound can be a silane-based compound having an oxygen-containing heterocycle. At least one ring-constituting element of the above-mentioned oxygen-containing heterocycle can be oxygen, and the remaining ring-constituting elements can be carbon.

[0117] The above-mentioned oxygen-containing heterocycles can be monocyclic rings such as oxiranyl, diepoxiranyl, oxetanyl, tetrahydrofuranyl, dioxolanyl, oxanyl, dioxanyl, or fused rings such as epoxycyclohexyl.

[0118] The above-mentioned silane-based compound can be a trialkoxysilane-based compound. For example, the above-mentioned silane-based compound can include a compound represented by the following Chemical Formula 4.

[0119] [Chemical Formula 4]

[0120]

[0121] In Chemical Formula 4, each of R6 to R8 can independently be methyl, ethyl, methoxy, or ethoxy, L can include at least one selected from the group consisting of divalent alkylene having 1 to 5 carbon atoms and oxygen, and R9 can be the above-mentioned oxygen-containing heterocycle.

[0122] In some embodiments, L can be a divalent alkylene in which CH2 is replaced by oxygen. For example, L can be methyleneoxypropyl (-CH2-O-CH2CH2CH2-).

[0123] According to the exemplary embodiment, relative to 100 parts by weight of the above-mentioned acrylic copolymer, the content of the above-mentioned silane-based compound can be 0.01 part by weight to 3 parts by weight.

[0124] In some embodiments, relative to 100 parts by weight of the above-mentioned acrylic copolymer, the content of the above-mentioned silane coupling agent can be 0.01 part by weight to 3 parts by weight, for example, it can 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.

[0125] <Adhesive Sheet>

[0126] Hereinafter, embodiments of the present invention will be described more specifically with reference to the accompanying drawings. However, the following drawings attached to this specification are illustrations of exemplary embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the above-mentioned invention content. Therefore, the present invention should not be construed as being limited only to the matters described in these drawings.

[0127] Figure 1 It is a schematic cross-sectional view showing an adhesive sheet of an exemplary embodiment.

[0128] Refer to Figure 1 , the adhesive sheet of the exemplary embodiment can 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.

[0129] The above-mentioned adhesive layer can be formed from the above-mentioned adhesive composition. For example, the above-mentioned adhesive layer 120 can be formed by coating 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 bis(fluorosulfonyl)imide anion on the substrate film 110 and then curing it.

[0130] In some embodiments, the above-mentioned substrate film 110 can include an acrylic resin, a cellulose resin, a polyolefin resin, a polyester resin, etc. In this case, the transparency, mechanical strength, thermal stability, moisture resistance, isotropy, etc. of the substrate film 110 can be improved.

[0131] For example, the above-mentioned substrate film 110 can include: acrylic resins such as poly(methyl)methacrylate, poly(methyl)ethyl acrylate; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, polybutylene naphthalate; cellulose resins such as diacetyl cellulose, triacetyl cellulose, butenyl acetate cellulose; polyolefin resins such as polyethylene, polypropylene, cycloolefins, polyolefins having a norbornene structure, ethylene-propylene copolymers; sulfone resins; polyether-ether ketone resins; allylated resins; or a mixture of the above resins.

[0132] In one embodiment, at least one surface of the above-mentioned substrate 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, sandblasting treatment, primer treatment, etc. can be performed on one surface of the above-mentioned substrate film 110.

[0133] Through the above surface treatment, carboxylic acid derivatives (R-COOH) can be generated on the surface of the substrate film 110. The carboxyl group of the above carboxylic acid derivative can react with the adhesive composition, thereby further improving the adhesion between the adhesive layer and the substrate film.

[0134] In one embodiment, the surface of the above-mentioned substrate film 110 may not be saponified. Since the surface of the substrate film for the adhesive sheet is hydrophobic, the adhesion and adhesiveness to the adhesive may deteriorate. In this case, a pretreatment process of immersing the surface of the substrate film in an alkaline aqueous solution for saponification can be performed, or a separate coating can be formed between the substrate and the adhesive, or the surface of the substrate film can be corona or plasma-treated to improve the adhesiveness between the substrate and the adhesive.

[0135] However, in the case of performing the saponification process or forming a separate coating, the process becomes complicated, which may lead to a decrease in the yield and processability of the adhesive sheet, and due to the additional pretreatment or coating formation process, contamination and quality degradation of the adhesive sheet may occur.

[0136] Due to the organosilicon compound having a malonyl group or an acetoacetyl group, the adhesive composition of the above embodiment increases the affinity between the surface of the substrate film 110 and the adhesive composition, and thus can improve the adhesion between the adhesive layer 120 and the surface of the substrate film 110. In addition, it can maintain heat resistance, heat and humidity durability, and adhesion reliability under harsh conditions of high temperature and high humidity, and can achieve improved reworkability even after being placed under the above harsh conditions for a long time.

[0137] The surface resistivity value of the adhesive layer can be 1×10 11 Ω / □ or less. In exemplary embodiments, it can be 7×10 10 Ω / □ or less or 5×10 10 Ω / □ or less.

[0138] The adhesive layer 120 can be formed by coating the above adhesive composition on at least one surface of the substrate film 110 and drying and / or curing. For example, the above adhesive composition can be coated on the substrate film 110 by coating methods such as roll coating, gravure coating, reverse coating, spraying, air knife coating, die coating, etc., thereby forming the adhesive layer 120.

[0139] According to exemplary embodiments, the gel fraction of the above adhesive layer 120 can be 60% - 80%, for example, it can be 65% - 75%. The gel fraction of the adhesive layer 120 can be calculated by the following formula 1.

[0140] [Formula 1]

[0141] Gel fraction (%) = W2 / W1 × 100

[0142] In Formula 1, W1 can be the initial weight of the adhesive layer. W2 can be the weight measured after immersing the above adhesive layer in an ethyl acetate solution at room temperature for 3 days and drying at 120°C for 24 hours.

[0143] When the gel fraction of the adhesive layer 120 is less than 60%, due to the low crosslinking degree and cohesion, the durability over time and the reworkability may decrease. When the gel fraction of the adhesive layer 120 is higher than 80%, due to excessive crosslinking, the durability and adhesion of the adhesive layer 120 may decrease, and damage to the object may occur when peeling the adhesive sheet.

[0144] Referring to Figure 1 , the adhesive sheet may further include a release film 130 disposed on one surface of the adhesive layer 120. For example, the above adhesive sheet may be sequentially provided with a substrate film 110, an adhesive layer 120, and a release film 130.

[0145] In some embodiments, the above-mentioned adhesive sheet may be provided in a form in which a base film 110 and a release film 130 are attached to both sides. Refer to Figure 2 , when using the adhesive sheet, the release film 130 can be removed from the adhesive sheet. In this case, the release film 130 can be removed from the adhesive sheet, and then the exposed adhesive layer 120 can be attached to an adherend (e.g., a display panel).

[0146] In some embodiments, the above-mentioned adhesive sheet may be provided in a form in which release films 130 are attached to both sides of the adhesive layer 120.

[0147] For example, the release film 130 attached to one side of the adhesive sheet can be removed, and then the optical base film 110 or a functional layer (e.g., an antireflection layer) can be attached to the exposed surface of the adhesive layer 120 to form a laminate.

[0148] In one embodiment, the antireflection layer may also be provided as an antireflection plate attached to one side of the optical base film 110, and the adhesive layer 120 of the adhesive sheet can also be attached to the other side of the optical base film 110.

[0149] <Optical film, Image display device>

[0150] Figure 3 is a schematic cross-sectional view of an optical film for illustrating exemplary embodiments.

[0151] Refer to Figure 3 , the optical film may include a base film 110, an adhesive layer 120 disposed on one side of the base film 110, and an optical functional layer 140 disposed on the other side of the base film 110.

[0152] For example, the optical film can be formed by forming an optical functional layer 140 on one side of the base film 110 and then coating an adhesive composition on the other side of the base film 110 and curing it to form the adhesive layer 120.

[0153] In some embodiments, the optical functional layer 140 may include an antireflection layer, a hard coat layer, a retardation layer, a polarizer, etc. For example, the optical film can be provided as an antireflection film, a hard coat film, a window film, a retardation film, a polarizing plate, etc. according to the difference of the optical functional layer 140.

[0154] In some embodiments, the optical film may further include a release film disposed on one side of the adhesive layer 120. For example, the optical film can be provided in a form in which a base film 110 and a release film are attached to both sides of the adhesive layer 120. In this case, the release film formed on one side of the adhesive layer 120 can be removed, and then the exposed surface of the adhesive layer 120 can be attached to an object (e.g., a display panel).

[0155] 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 above-mentioned 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 above-mentioned adhesive layer 120, an object body (e.g., a display panel) can be attached to the exposed surface.

[0156] Figure 4 It is a schematic cross-sectional view of an image display device for illustrating an exemplary embodiment.

[0157] According to an exemplary embodiment, the above-mentioned image display device may include a display panel 200 and an optical film disposed on the above-mentioned display panel 200.

[0158] In some embodiments, the image display device may include a display panel 200 and an optical film disposed on the upper surface of the above-mentioned display panel via an adhesive layer 120. For example, an image display device can be provided by removing the release film from the above-mentioned optical film and attaching the exposed adhesive layer 120 to the display panel 200.

[0159] The above-mentioned 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).

[0160] In addition to the above-mentioned components, the image display device may further include other components well-known in the art. For example, it may further include a retardation film, a hard coat film, a protective film, a window film, a touch panel, etc. The above-mentioned components can be attached to each other using the adhesive composition of the exemplary embodiment.

[0161] As described above, by improving the adhesion and bonding between the above-mentioned base film 110 and the above-mentioned adhesive layer 120, improved durability and stability can be achieved. Therefore, even under physical external forces such as repeated bending or under harsh conditions of high temperature and high humidity, the adhesion reliability of the image display device can be maintained for a long time, and the breakage, peeling, and warping phenomena of each component can be prevented.

[0162] In addition, when reworking after being placed under harsh conditions of high temperature and high humidity for a long time, the release of the adhesive sheet can be carried out without damage to the object body or residue of the adhesive substance.

[0163] Hereinafter, the embodiments of the present invention will be further described with reference to specific experimental examples. It is obvious to those skilled in the art that the embodiments and comparative examples included in the experimental examples are only illustrations of the present invention and do not limit the scope of the appended claims. Various changes and modifications can be made to the embodiments within the scope and technical concept of the present invention, and of course, such changes and modifications also fall within the scope of the appended claims.

[0164] Production Example 1: Production of Acrylic Copolymer (A-1)

[0165] In a 1 L reactor with nitrogen reflux and a cooling device for easy temperature adjustment, 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 prepare a mixture. To remove oxygen, nitrogen was passed through the above mixture for 1 hour for replacement, and then the temperature was maintained at 62°C. After the mixture was stirred uniformly, 0.07 parts by weight of azobisisobutyronitrile (AIBN) as a reaction initiator was added and reacted for 8 hours to prepare an acrylic copolymer (A-1) having a weight average molecular weight of 1.51 million.

[0166] Production Examples 2 to 6

[0167] As shown in Table 1 below, the types and contents of the monomers were adjusted, and except for this, the acrylic copolymer was prepared by the same method as in Production Example 1. The monomer content is expressed in units of % by weight based on the total weight of the polymerizable mixture.

[0168] [Table 1]

[0169]

[0170] M-1: n-butyl acrylate

[0171] M-2: methyl acrylate

[0172] M-3: phenoxyethyl acrylate

[0173] M-4: acrylic acid

[0174] M-5: 2-hydroxyethyl acrylate

[0175] Examples 1 to 23 and Comparative Examples 1 to 4

[0176] (1) Preparation of the adhesive composition

[0177] A mixture was prepared according to the components and contents shown in Table 2 below, and then diluted in ethyl acetate to a concentration of 14% by weight of the solid content to prepare the 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.

[0178] (2) Preparation of the adhesive sheet

[0179] The manufactured adhesive composition was coated on a release film coated with a silicone release agent and dried at 100 °C for 2 minutes to form an adhesive layer with a thickness of 20 μm. A polarizing plate as a base film was laminated on the formed adhesive layer to manufacture an adhesive sheet. The above polarizing plate used an iodine-based polarizing plate (thickness 185 μm) in which a corona-discharge-treated cycloolefin (COP) film was laminated on one side of a polyvinyl alcohol (PVA) polarizer and a triacetyl cellulose (TAC) film was laminated on the other side. Lamination was performed in such a manner that the corona-discharge-treated COP film surface was in contact with the adhesive layer.

[0180] [Table 2]

[0181]

[0182] (A) Acrylic copolymer

[0183] A-1 to A-6: Acrylic copolymers of Production Examples 1 to 6

[0184] (B) Crosslinking agent

[0185] B-1 D-110N: XDI-based crosslinking agent (Mitsui Chemicals)

[0186] B-2 Coronate-HXR: HDI-based crosslinking agent (Nippon Polyurethane Industry Co., Ltd.)

[0187] (C) Silane-based compound

[0188] C-1: KBM-403 (3-glycidoxypropyltrimethoxysilane, Shin-Etsu)

[0189] C-2: KBE-402 (3-glycidoxypropylmethyldiethoxysilane, Shin-Etsu)

[0190] C-3: KBM-303 (2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, Shin-Etsu)

[0191] C-4: X-12-989MS (the following Chemical Formula 5, Shin-Etsu)

[0192] [Chemical Formula 5]

[0193]

[0194] (D) Ionic antistatic agent

[0195] D-1: Compound represented by the following Chemical Formula 1-1 (ImC12-FSI, melting point: 42 °C)

[0196] [Chemical Formula 1-1]

[0197]

[0198] D-2: The compound represented by the following Chemical Formula 1-2 (ImC14-FSI, melting point: 66 °C)

[0199] [Chemical Formula 1-2]

[0200]

[0201] D-3: The compound represented by the following Chemical Formula 1-3 (ImC18-FSI, melting point: 48 °C)

[0202] [Chemical Formula 1-3]

[0203]

[0204] D-4: The compound represented by the following Chemical Formula 1-4 (H-ImC14-FSI, melting point: 40 °C)

[0205] [Chemical Formula 1-4]

[0206]

[0207] D-5: IL-P-18-2 (1-octyl-4-methylpyridinium hexafluorophosphate, manufactured by Kyoei Chemical)

[0208] D-6: The compound represented by the following Chemical Formula 6

[0209] [Chemical Formula 6]

[0210]

[0211] (E) (meth)acrylate compound

[0212] E-1: AM-130G (methoxypolyethylene glycol #600 acrylate, n in Chemical Formula 2 is about 13, manufactured by Shin-Nakamura)

[0213] E-2: M-130G (methoxypolyethylene glycol methacrylate, n in Chemical Formula 2 is about 13, manufactured by Shin-Nakamura)

[0214] E-3: A-LEN-10 (ethoxylated o-phenylphenol acrylate, n in Chemical Formula 2 is 1, manufactured by Shin-Nakamura)

[0215] E-4: AM-30PG (methoxytripropylene glycol acrylate, n in Chemical Formula 2 is 3, manufactured by Shin-Nakamura)

[0216] E-5: n-butyl acrylate

[0217] Experimental Example

[0218] (1) Adhesion evaluation

[0219] After cutting the adhesive sheets of the examples and comparative examples into a length of 25 mm × a width of 100 mm and peeling off the release film, the exposed adhesive layer was attached to a glass substrate (#1737, manufactured by Corning), and autoclave treatment was performed at a temperature of 50 °C and a pressure of 5 atmospheres for 20 minutes to produce test pieces.

[0220] The above test pieces were placed at a temperature of 23 °C and a humidity of 50% RH for 24 hours. 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 o to measure the adhesion at room temperature.

[0221] (2) Reworkability measurement

[0222] After cutting the adhesive sheets of the examples and comparative examples into a length of 25 mm × a width of 100 mm and peeling off the release film, the exposed adhesive layer was attached to a glass substrate under a pressure of 0.25 MPa, and autoclave treatment was performed at a temperature of 50 °C and a pressure of 5 atmospheres for 20 minutes to produce test pieces.

[0223] To measure the heat-resistant reworkability, the above-produced test pieces were taken out after being placed in an oven at 80 °C for 10 hours and stored at room temperature for 120 hours, and then the adhesive layer was peeled off at a speed of 1.3 cm / sec.

[0224] To measure the humidity and heat-resistant reworkability, the above-produced test pieces were taken out after being placed in an oven at a temperature of 60 °C and a humidity of 90% RH for 12 hours and stored at room temperature for 120 hours, and then the adhesive layer was peeled off at a speed of 1.3 cm / sec.

[0225] <Evaluation criteria>

[0226] ○: Cleanly peeled off in both heat-resistant reworkability and humidity and heat-resistant reworkability, no adhesive residue on the glass substrate, and no tearing of the base film (TAC film).

[0227] ×: In one or more of heat-resistant reworkability and humidity and heat-resistant reworkability, either adhesive remains on the glass substrate or the base film (TAC film) is torn during peeling.

[0228] (3) Durability (heat resistance, humidity and heat resistance) evaluation

[0229] The adhesive sheets of the examples and comparative examples were cut into a length of 200 mm × a width of 300 mm, and after peeling off the release film, the exposed adhesive layer was attached to a glass substrate (210 mm × 350 mm × 0.7 mm), and then autoclave treatment (50 °C × 30 minutes, 0.5 MPa) was performed to produce test pieces. At this time, the pressure applied was 5 kg / cm 2 , and clean room operations were carried out to avoid generating bubbles or foreign matters.

[0230] In the heat resistance evaluation, after placing the test piece at a temperature of 80 °C for 1000 hours, it was observed whether bubbles or peeling occurred. In the damp heat resistance evaluation, after placing the test piece under the conditions of 60 °C and 90% RH for 1000 hours, it was observed whether bubbles or peeling occurred. At this time, before evaluating the state of the test piece, it was left at room temperature for 24 hours and then observed.

[0231] <Evaluation criteria>

[0232] : No bubbles or peeling;

[0233] ○: Bubbles or peeling < 5;

[0234] △: 5 ≤ bubbles or peeling < 10;

[0235] ×: 10 ≤ bubbles or peeling.

[0236] (4) Adhesion measurement

[0237] The above-produced adhesive sheet was cut into a size of 25 mm in length × 50 mm in width, and a polarizing plate was attached to a SUS304 plate with a double-sided adhesive tape (width: 25 mm, manufactured by SOOKWANG) on one side. Then, using an elastic rubber (neoprene, manufactured by Gouda), the adhesive layer side was reciprocated 20 times in the length (25 mm) direction at a pressure of 1 MPa and a speed of 0.1 m / s. The distance by which the adhesive layer was pushed on the TAC film at this time was measured to evaluate the adhesion.

[0238] (5) Antistatic property measurement

[0239] The above-produced adhesive sheet was cut into a length of 200 mm × a width of 300 mm, and after peeling off the release film, the surface resistivity value of the exposed adhesive layer was measured to evaluate the antistatic property. Regarding the measurement method, the surface resistivity was measured using a resistivity meter HIRESTA UP-HT450 (manufactured by Mitsubishi Chemical Analytech) under the conditions of 25 °C, 50% RH, 500 V, and 10 seconds.

[0240] The results are shown in Table 3 below.

[0241] [Table 3]

[0242]

[0243] Referring to Table 3, the adhesive sheet of the example can ensure the adhesion to the base film, and improved reworkability can also be achieved after long-term storage. In addition, the adhesive sheet of the example has a low surface resistance and improved antistatic properties, with few bubbles or peeling even in a harsh environment of high temperature and / or high humidity, and remains in an attached state.

[0244] On the other hand, for the adhesive sheet of the comparative example, the durability decreases or the reworkability deteriorates in a high-temperature environment.

[0245] The adhesive sheet of Comparative Example 1 is formed from a composition that does not contain a compound having an alkenyloxy group. Therefore, after the adhesive sheet is attached to the adherend and peeled after being placed at a high temperature, residues appear on the surface of the adherend or bubbles are generated, etc.

[0246] The adhesive sheets of Comparative Examples 2 and 3 are formed from a composition containing an antistatic agent having an anion of non-bis(fluorosulfonyl)imide. Therefore, the hygrothermal resistance of the adhesive sheet deteriorates significantly.

[0247] The adhesive sheet of Comparative Example 4 is formed from a composition containing an acrylate compound that does not have an alkenyloxy group. Therefore, the hygrothermal resistance and reworkability of the adhesive sheet are worse than those of the example.

[0248] The content described above is only an illustration of applying the principle of the present disclosure, and other configurations may also be included without departing from the scope of the present invention.

Claims

1. An adhesive composition, comprising: an acrylic copolymer, a crosslinking agent, an alkenyloxy group-containing (meth)acrylate compound, and an ionic antistatic agent having an imidazolium-based cation and a bis(fluorosulfonyl)imide anion.

2. The adhesive composition according to claim 1, wherein the ionic antistatic agent comprises an ionic compound represented by the following Chemical Formula 1: Chemical Formula 1 In Chemical Formula 1, R1 is hydrogen or methyl, and R2 is an alkyl group having 10 to 30 carbon atoms.

3. The adhesive composition according to claim 1, wherein the ionic antistatic agent has a melting point of 23°C or higher.

4. The adhesive composition according to claim 1, 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.

5. The adhesive composition according to claim 1, wherein the alkenyloxy group-containing (meth)acrylate compound is represented by the following Chemical Formula 2: Chemical Formula 2 In the chemical formula 2, R a is hydrogen or methyl, R b is an alkylene group having 1 to 10 carbon atoms, 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 from 1 to 25.

6. The adhesive composition according to claim 5, 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.

7. The adhesive composition according to claim 1, wherein the content of the alkenyloxy group-containing (meth)acrylate compound is 0.1 to 5 parts by weight based on 100 parts by weight of the acrylic copolymer.

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

9. The adhesive composition according to claim 8, wherein the (alkyl)acrylate monomer comprises a first monomer and a second monomer, the first monomer being an (alkyl)acrylate monomer having 1 to 3 carbon atoms, and the second monomer being an (alkyl)acrylate monomer having 4 to 12 carbon atoms.

10. The adhesive composition according to claim 8, wherein the polar functional group of the crosslinkable monomer containing a polar functional group comprises at least one of a carboxyl group, a hydroxyl group, an amide group, and an amino group.

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

12. The adhesive composition according to claim 1, wherein the content of the crosslinking agent is 0.1 to 3 parts by weight based on 100 parts by weight of the acrylic copolymer.

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

14. The adhesive composition according to claim 13, wherein the content of the silane compound is 0.01 to 3 parts by weight based on 100 parts by weight of the acrylic copolymer.

15. An adhesive sheet, comprising a base film and an adhesive layer, wherein the adhesive layer is disposed on the base film and formed using the adhesive composition according to claim 1.

16. The pressure-sensitive adhesive composition according to claim 15, wherein the surface resistivity value of the pressure-sensitive adhesive layer has a value of 1×10 11 Ω / □ or less.

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

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

Images