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

Abstract

To provide an adhesive composition that enables formation of an adhesive layer with improved physical properties, an adhesive sheet comprising the adhesive layer obtained using the adhesive composition, and an optical film manufactured from the adhesive sheet.SOLUTION: The present invention provides an adhesive composition that contains an acrylic copolymer, a crosslinker, an organosilicon compound including at least two carbonyl groups, and an ionic antistatic agent having an imidazolium-based cation and a bis(fluorosulfonyl)imide anion. An adhesive layer obtained from the adhesive composition exhibits high adhesion to a base film and enables provision of an optical film with enhanced reworkability even after prolonged exposure to severe conditions such as 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 properties of the image display device.

[0003] In recent years, displays having high reliability even under severe conditions of high temperature and high humidity or under 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 off even under severe conditions or external impact.

[0004] Therefore, there is a need for an adhesive or an adhesive sheet that has high adhesive strength and durability and can bond 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 physical properties.

[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 organosilicon compound containing at least two or more carbonyl groups, 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 acrylic copolymer is formed from a polymerizable mixture containing a (meth)acrylate monomer and a crosslinkable monomer containing a polar functional group.

[0009] 3. The adhesive composition according to item 2 above, wherein the (meth)acrylate monomer includes a first monomer which is an alkyl (meth)acrylate monomer having 1 to 3 carbon atoms and a second monomer which is an alkyl (meth)acrylate monomer having 4 to 12 carbon atoms.

[0010] 4. The adhesive composition according to item 2 above, 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.

[0011] 5. The adhesive composition according to item 1 above, wherein the ionic antistatic agent includes an ionic compound represented by the following Chemical Formula 1. [Chemical Formula] (In the above Chemical Formula 1, R1 is hydrogen or a methyl group, and R2 is an alkyl group having 10 to 30 carbon atoms.)

[0012] 6. The adhesive composition according to item 1 above, wherein the melting point of the ionic antistatic agent is 23°C or higher.

[0013] 7. The adhesive composition according to item 1 above, wherein the content of the ionic antistatic agent is 0.01 to 7 parts by weight with respect to 100 parts by weight of the acrylic copolymer.

[0014] 8. The adhesive composition according to item 1 above, wherein the organosilicon compound contains a nitrogen atom or a sulfur atom.

[0015] 9. In item 8 above, the organosilicon compound-containing pressure-sensitive adhesive composition contains an amine group or a sulfide group.

[0016] 10. In item 1 above, the organosilicon compound-containing pressure-sensitive adhesive composition has two carbonyl groups linked by a methylene group.

[0017] 11. In item 10 above, the organosilicon compound-containing pressure-sensitive adhesive composition has a malonyl group or an acetoacetyl group.

[0018] 12. In item 1 above, the organosilicon compound-containing pressure-sensitive adhesive composition contains a compound represented by the following Chemical Formula 2 or the following Chemical Formula 3.

Chemical formula

Chemical formula

[0019] 13. In item 1 above, the content of the organosilicon compound is 0.1 part by weight to 3 parts by weight with respect to 100 parts by weight of the acrylic copolymer in the pressure-sensitive adhesive composition.

[0020] 14. In item 1 above, 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 in the pressure-sensitive adhesive composition.

[0021] 15. In the above item 1, the crosslinking agent contains a non-yellowing type isocyanate-based crosslinking agent, and it is an adhesive composition.

[0022] 16. An adhesive sheet including a base film and an adhesive layer disposed on the base film and formed using the adhesive composition according to any one of the above-described embodiments.

[0023] 17. In the above item 16, the rate of change in adhesive strength of the adhesive sheet according to the following formula 2 is greater than 1 and less than or equal to 1.7, and it is an adhesive sheet.

Number

[0024] 18. In the above item 16, the value of the surface specific resistance of the adhesive layer is 5×10 10 Ω / □ or less, and it is an adhesive sheet.

[0025] 19. 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 any one of the above-described embodiments, and an antireflection layer disposed on the lower surface of the base film.

[0026] 20. An image display device including the optical film according to the above item 19.

Advantages of the Invention

[0027] An adhesive composition according to an exemplary embodiment of the present invention can have improved chemical stability and reworkability.

[0028] In addition, an adhesive layer having high adhesion and adhesiveness to an adherend can be realized from the adhesive composition, and the adhesive layer can have high stability even under severe environments of high temperature and high humidity.

[0029] An adhesive sheet according to an exemplary embodiment of the present invention can include an adhesive layer having improved antistatic properties.

Brief Description of the Drawings

[0030]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0031] An embodiment of the present invention provides an adhesive sheet and an optical film including an adhesive layer formed from an adhesive composition including an acrylic copolymer, a crosslinking agent, an organosilicon compound containing at least two or more carbonyl groups, and an ionic antistatic agent having an imidazolium-based cation and a bisfluorosulfonylimide anion.

[0032] Hereinafter, the present invention will be described in detail. <Adhesive Composition> The pressure-sensitive adhesive composition according to an exemplary embodiment may include an acrylic copolymer. The acrylic copolymer may include a copolymer formed from a polymerizable mixture including a (meth)acrylate monomer and a crosslinkable monomer containing a polar functional group. As used herein, the term "(meth)acrylate" is used to mean including acrylate or methacrylate.

[0033] The (meth)acrylate monomer may 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.

[0034] The first monomer and the second monomer may be compounds derived from an aliphatic alcohol having 1 to 12 carbon atoms.

[0035] 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.

[0036] In some embodiments, the content of the first monomer may be 10% by weight to 40% by weight based on the total weight of the polymerizable mixture, and for example, it may be 15% by weight to 35% by weight. Within this range, the adhesive strength and reworkability of the adhesive sheet can be sufficiently improved.

[0037] 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, etc. 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.

[0038] In some embodiments, the content of the second monomer may be 60% to 89% by weight, for example, 65% to 80% by weight, based on the total weight of the polymerizable mixture. Within this range, it is possible to prevent a decrease in the cohesive force of the pressure-sensitive adhesive composition and a decrease in the durability of the pressure-sensitive adhesive layer, and to improve the crosslinking density and the adhesive strength of the pressure-sensitive adhesive layer.

[0039] According to an exemplary embodiment, by containing both the first monomer and the second monomer, the polymerizable mixture can prevent damage to the substrate and residue of the pressure-sensitive adhesive substance in rework while achieving improved adhesive strength.

[0040] The polar functional group-containing crosslinkable monomer can include a crosslinkable group capable of undergoing a polymerization reaction with the (meth)acrylate-based monomer to form a copolymer, and a polar functional group that can be included in a form bonded to the copolymer chain.

[0041] 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 destruction of the cohesive force of the pressure-sensitive adhesive layer under high-temperature / high-humidity conditions and impart adhesive strength.

[0042] 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.

[0043] 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.

[0044] 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 pressure-sensitive adhesive composition can be ensured and the durability of the pressure-sensitive adhesive sheet can be improved, and the adhesive force and durability can be improved by an appropriate gel fraction of the pressure-sensitive adhesive composition.

[0045] The carboxy group-containing crosslinkable monomer can play a role of imparting adhesive force to the pressure-sensitive adhesive composition. For example, since the acrylic copolymer has an acidic group derived from the carboxy group-containing crosslinkable monomer, the adhesion and crosslinking degree of the pressure-sensitive adhesive composition can be improved.

[0046] 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.

[0047] In some embodiments, the content of the carboxy group-containing crosslinkable monomer may be more than 0% by weight and 1% by weight or less based on the total weight of the polymerizable mixture. For example, the content of the carboxy group-containing crosslinkable monomer may be 0.01% by weight to 1% by weight, for example, 0.05% by weight to 1% by weight, or 0.05% by weight to 0.5% by weight, based on the total weight of the polymerizable mixture.

[0048] When the content of the carboxy group-containing crosslinkable monomer is within the above range, the adhesive force of the pressure-sensitive adhesive sheet formed from the pressure-sensitive adhesive composition can be appropriately improved, thereby improving the reworkability and preventing the migration of the ionic antistatic agent to the surface of the pressure-sensitive adhesive sheet.

[0049] When the polymerizable mixture does not contain a carboxy group-containing crosslinkable monomer, the adhesive force, adhesion and durability in a harsh environment of the adhesive layer may decrease.

[0050] The hydroxy group-containing crosslinkable monomer can impart a highly polar hydroxy group to the acrylic copolymer. Thereby, the adhesive force of the acrylic copolymer to a polar base material can be enhanced.

[0051] 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 in which the alkylene group has 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.

[0052] In some embodiments, the content of the hydroxy group-containing crosslinkable monomer may be 5% by weight or less based on the total weight of the polymerizable mixture. For example, the content of the hydroxy group-containing crosslinkable monomer may be 0.1% by weight to 4% by weight, 0.1% by weight to 3% by weight, or 0.5% by weight to 3% by weight based on the total weight of the polymerizable mixture. 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.

[0053] 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.

[0054] 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.

[0055] 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. In addition, solvents, polymerization initiators, chain transfer agents for controlling the molecular weight, etc. commonly used during polymerization can be used.

[0056] In some embodiments, the weight average molecular weight (polystyrene equivalent, Mw) of the acrylic copolymer may be 50,000 to 2,000,000, for example, it may be 400,000 to 2,000,000. For example, the weight average molecular weight can be measured by Gel Permeation Chromatography (GPC).

[0057] 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 the adhesive layer formed from the adhesive composition.

[0058] By including the ionic compound as an 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.

[0059] 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 the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition containing the liquid ionic compound can be reduced, and contamination of the adherend can be prevented.

[0060] 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 pressure-sensitive adhesive layer in a room temperature environment can be reduced. Thereby, the ionic antistatic agent does not elute to the end of the pressure-sensitive adhesive layer, and contamination of the adherend can be prevented.

[0061] The ionic antistatic agent may include a long-chain alkyl group bonded to a cationic nitrogen of an imidazolium skeleton. Thereby, the ionic antistatic agent can be prevented from eluting from the pressure-sensitive adhesive layer as an ionic solid at room temperature.

[0062] In some embodiments, the ionic antistatic agent may include an ionic compound represented by the following Chemical Formula 1.

[0063]

Chemical Formula

[0064] In Chemical Formula 1, R1 may be hydrogen or a methyl group. For example, R1 may be a methyl group.

[0065] 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.

[0066] According to an exemplary embodiment, the 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.

[0067] In an exemplary embodiment, the content of the ionic antistatic agent may be 0.01 part by weight to 7 parts by weight based on 100 parts by weight of the acrylic copolymer. In some embodiments, the content of the ionic antistatic agent may be 0.1 part by weight to 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 based on 100 parts by weight of the acrylic copolymer.

[0068] Within the above range, the antistatic property of the adhesive layer can be improved while maintaining excellent durability of the adhesive layer.

[0069] In some embodiments, the adhesive composition includes a crosslinking agent.

[0070] The crosslinking agent can play a role in improving the cohesive force, adhesion, and high-temperature reliability of the adhesive and maintaining the shape of the adhesive.

[0071] 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.

[0072] The isocyanate-based compound has high reactivity with respect to polar functional groups and can have improved adhesion to a corona discharge-treated or plasma-treated substrate film.

[0073] Examples of the isocyanate-based compound include diisocyanate compounds such as xylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and tetramethylxylene diisocyanate; an adduct obtained by reacting 3 equivalents of a diisocyanate compound with 1 equivalent of a polyhydric alcohol-based compound such as trimethylolpropane, an isocyanurate body obtained by self-condensing 3 equivalents of a diisocyanate compound, a biuret body in which the remaining 1 equivalent of diisocyanate is condensed with a diisocyanate urea obtained from 2 equivalents out 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.

[0074] In some embodiments, the content of the crosslinking agent may be 0.1 part by weight to 3 parts by weight, for example, 0.1 part by weight to 2 parts by weight, based on 100 parts by weight of the acrylic copolymer. Within the above range, the chains of the acrylic copolymer can be appropriately crosslinked to improve the adhesive durability and cutability of the adhesive layer. Also, the adhesion of the adhesive sheet to the adherend can be improved.

[0075] An adhesive composition according to an exemplary embodiment can include an organosilicon compound having at least two or more carbonyl groups. In one embodiment, the organosilicon compound can include two carbonyl groups linked by a methylene group. Accordingly, the adhesion of the adhesive composition can be increased by the organosilicon compound, and the generation, floating, and breakage of air bubbles in the adhesive layer can be suppressed.

[0076] In some embodiments, the organosilicon compound can include a malonyl group or an acetoacetyl group. In this case, the adhesiveness of the adhesive composition can be further improved by the malonyl group or the acetoacetyl group, and the heat resistance and the heat and humidity resistance can be improved.

[0077] In some embodiments, the organosilicon compound can have a nitrogen atom or a sulfur atom. For example, the organosilicon compound can include an amine group or a sulfide group. By the organosilicon compound having an amine group or a sulfide group together with a malonyl group or an acetoacetyl group, improved reworkability can be realized even after being left for a long time under heat and heat and humidity conditions, and the adhesive durability and the adhesive reliability can be improved.

[0078] In some embodiments, the organosilicon compound can include a compound represented by the following Chemical Formula 2 or the following Chemical Formula 3.

[0079]

Chemical Formula

[0080]

Chemical Formula

[0081] R3 may be an alkoxy group having 1 to 12 carbon atoms. Examples of the R3 include a methoxy group, an ethoxy group, an isopropyloxy group, etc., and from the viewpoint of reworkability, for example, it may be a methoxy group.

[0082] R8 may be an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms. Examples of the R8 include a methyl group, an ethyl group, an isopropyl group, a methoxy group, an ethoxy group, an isopropyloxy group, etc., and from the viewpoint of reworkability, for example, it may be a methyl group or a methoxy group.

[0083] R4 and R9 may each independently be a divalent aliphatic hydrocarbon group having 1 to 30 carbon atoms. For example, R4 and R9 may be an alkylene group having 1 to 30 carbon atoms, an alkenylene group having 2 to 30 carbon atoms, or an alkynylene group having 2 to 30 carbon atoms.

[0084] R5 to R7 and R 10 ~R 12 may each independently be hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. At least one of the R5 to R7 and at least one of R 10 ~R 12 may be an alkoxy group having 1 to 12 carbon atoms, and the number of carbon atoms can be adjusted in consideration of the relationship between adhesiveness and reworkability.

[0085] In an exemplary embodiment, the content of the organosilicon compound may be 0.1 part by weight to 3 parts by weight with respect to 100 parts by weight of the acrylic copolymer. In some embodiments, the content of the organosilicon compound may be 0.1 part by weight to 1 part by weight, 0.3 part by weight to 0.7 part by weight, or 0.3 part by weight to 0.5 part by weight with respect to 100 parts by weight of the acrylic copolymer.

[0086] Within the above range, the durability and adhesion of the adhesive layer formed from the adhesive composition can be improved.

[0087] The pressure-sensitive adhesive composition may further contain ordinary additives known in the art in order to adjust the adhesive strength, cohesive force, viscosity, elastic modulus, glass transition temperature, etc. required depending on the application. For example, the pressure-sensitive adhesive composition may contain, as additives, tackifiers, antioxidants, corrosion inhibitors, leveling agents, surface lubricants, dyes, pigments, defoamers, fillers, light stabilizers, plasticizers, and the like.

[0088] <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 preferred embodiments of the present invention and serve to help further understand 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.

[0089] FIG. 1 is a schematic cross-sectional view showing an adhesive sheet according to an exemplary embodiment.

[0090] Referring to FIG. 1, an adhesive sheet according to an exemplary embodiment may include a base film 110, a pressure-sensitive 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 pressure-sensitive adhesive layer 120.

[0091] The pressure-sensitive adhesive layer 120 can be formed from the above-described pressure-sensitive adhesive composition. For example, the pressure-sensitive adhesive layer 120 can be formed by applying, on the base film 110, a pressure-sensitive adhesive composition containing an acrylic copolymer, a crosslinking agent, an organosilicon compound containing at least two or more carbonyl groups, and an ionic antistatic agent having an imidazolium-based cation and a bisfluorosulfonylimide anion, and then curing.

[0092] 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.

[0093] For example, the base film 110 can 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.

[0094] 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.

[0095] By the above 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 between the adhesive layer 120 and the base film.

[0096] In one embodiment, the surface of the base film 110 may not be saponification-treated. Since the surface of the base film 110 used for the adhesive sheet is hydrophobic, the adhesion and adhesive strength to the adhesive may deteriorate. In this case, the adhesion between the base material and the adhesive can be improved by performing a pretreatment step of immersing the surface of the base film 110 in an alkaline aqueous solution for saponification, forming another coating layer between the base material and the adhesive, or subjecting the surface of the base film 110 to corona or plasma treatment.

[0097] However, when performing the saponification process or forming another coating layer, the process may become complicated, 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.

[0098] The organosilicon compound having a malonyl group or an acetoacetyl group contained in the pressure-sensitive adhesive composition according to the above-described embodiment can enhance the affinity between the surface of the base film 110 and the pressure-sensitive adhesive composition. Thereby, the adhesion of the pressure-sensitive adhesive layer 120 to the surface of the base film 110 can be improved. Further, heat and moisture resistance durability and adhesion reliability under severe conditions of high temperature and high humidity can be maintained, and improved reworkability can be achieved even after being left for a long time under the severe conditions.

[0099] The pressure-sensitive 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 pressure-sensitive 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.

[0100] In one embodiment, the surface resistivity value of the pressure-sensitive adhesive layer 120 may be 5×10 10 Ω / □ or less. For example, the surface resistivity value of the pressure-sensitive adhesive layer 120 may be 4.5×10 10 Ω / □ or less.

[0101] According to an exemplary embodiment, the gel fraction of the pressure-sensitive adhesive layer 120 may be 60% to 80%, for example, 65% to 75%. The gel fraction of the pressure-sensitive adhesive layer 120 can be calculated by the following formula 1.

[0102]

Equation

[0103] 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.

[0104] When 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 cohesive force. When 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.

[0105] According to an exemplary embodiment, the rate of change in adhesive force of the adhesive sheet according to the following Formula 2 may be greater than 1 and less than or equal to 1.7. In this range, the adhesive reliability at room temperature and high temperature can be ensured, and improved reworkability can be realized.

[0106]

Number

[0107] In Formula 2, P C can represent the adhesive force measured by peeling the adhesive sheet attached to the adherend at a peeling speed of 300 mm / min and a peeling angle of 180° from the adherend under the conditions of a temperature of 23°C and a relative humidity of 50% after leaving it for 24 hours under the conditions.

[0108] P H can represent the adhesive force measured by peeling the adhesive sheet attached to the adherend at a peeling speed of 300 mm / min and a peeling angle of 180° from the adherend under the conditions of a temperature of 23°C and a relative humidity of 50% after leaving it for 48 hours under the conditions of a temperature of 50°C and a relative humidity of 50%.

[0109] The adhesion change rate can indicate the ratio of the adhesion at a heated temperature (about 50°C) to the adhesion at room temperature (about 23°C), and can be used as a measure for judging the reworkability after being left at a heated temperature for a long time.

[0110] 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 can be formed by sequentially disposing a base film 110, an adhesive layer 120, and a release film 130.

[0111] [[ID=I7]] In some embodiments, the adhesive sheet can 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 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 the exposed adhesive layer 120 can be attached to an object to be adhered (for example, a display panel).

[0112] In some embodiments, the adhesive sheet can be provided in a form in which the release film 130 is attached to both sides of the adhesive layer 120.

[0113] For example, 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, a laminate can be formed.

[0114] In one embodiment, the antireflection layer may be provided as an antireflection plate attached to one surface of the optical base film 110, or may be attached to the other surface of the optical base film 110 to which the adhesive layer 120 of the adhesive sheet is attached.

[0115] <Optical Film, Image Display Device> FIG. 3 is a schematic cross-sectional view for explaining an optical film according to an exemplary embodiment.

[0116] Referring to FIG. 3, the optical film can 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.

[0117] For example, after forming the optical functional layer 140 on one surface of the substrate film 110, an adhesive composition can be applied and cured on the other surface of the substrate film 110 to form the adhesive layer 120.

[0118] In some embodiments, the optical functional layer 140 can include an anti-reflection layer, a hard coat layer, a retardation layer, a polarizer, etc. For example, the optical film can be provided as an anti-reflection film, a hard coat film, a window film, a retardation film, a polarizing plate, etc., according to the optical functional layer 140.

[0119] In some embodiments, the optical film can further include a release film 130 disposed on one surface of the adhesive layer 120. For example, the optical film can 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 (e.g., a display panel).

[0120] In some embodiments, when release films 130 are attached to both surfaces of the adhesive layer 120, after removing one surface's release film 130, the optical functional layer 140 can be attached to the exposed surface, and after removing the remaining release film 130 on the other surface of the adhesive layer 120, an object (e.g., a display panel) can be attached to the exposed surface.

[0121] FIG. 4 is a schematic cross-sectional view for explaining an image display device according to an exemplary embodiment.

[0122] 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.

[0123] 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 200 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.

[0124] 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).

[0125] 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.

[0126] As described above, by improving the adhesion and bonding properties between the base film 110 and the adhesive layer 120, the durability and mechanical stability of the optical film can be improved. Therefore, the adhesive reliability of the image display device can be maintained for a long time even under physical external forces such as repeated bending, or under harsh conditions of high temperature and high humidity, and breakage, peeling, and lifting phenomena of each component can be prevented.

[0127] Also, after being left for a long time under harsh 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.

[0128] Hereinafter, specific examples are presented to facilitate the understanding of the present invention. However, these examples merely illustrate the present invention and do not limit the appended claims. It is obvious to those skilled in the art that various changes and modifications can be made to the examples within the scope of the present invention and the scope of the technical idea. It is natural that such variations and modifications belong to the appended claims.

[0129] Production Example Production Example 1: Production of Acrylic Copolymer (A-1) Into a 1 L reactor equipped with a cooling device so that nitrogen gas is refluxed and temperature adjustment is easy, 100 parts by weight of a monomer mixture containing 77.8% by weight of n-butyl acrylate (BA), 20% by weight of methyl acrylate (MA), 0.2% by weight of acrylic acid (AA), and 2.0% by weight of 2-hydroxyethyl methacrylate (2-HEMA), 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 1.2 million.

[0130] Production Example 2: Production of Acrylic Copolymer (A-2) An acrylic copolymer (A-2) having a weight average molecular weight of 1.25 million was produced in the same manner as in Production Example 1, except that a monomer mixture containing 73.8% by weight of n-butyl acrylate (BA), 25% by weight of methyl acrylate (MA), 0.2% by weight of acrylic acid (AA), and 1.0% by weight of 2-hydroxyethyl methacrylate (2-HEMA) was used.

[0131] Production Example 3: Production of Acrylic Copolymer (A-3) An acrylic copolymer (A-3) with a weight average molecular weight of 1.22 million was produced in the same manner as in Production Example 1, except that a monomer mixture containing 69.3% by weight of n-butyl acrylate (BA), 30% by weight of methyl acrylate (MA), 0.2% by weight of acrylic acid (AA), and 0.5% by weight of 2-hydroxyethyl methacrylate (2-HEMA) was used.

[0132] Examples and Comparative Examples (1) Production of the pressure-sensitive adhesive composition The acrylic copolymer (A), crosslinking agent (B), organosilicon compound (C), and ionic antistatic agent (D) were mixed with the components and contents shown in Table 1 below, and then diluted with ethyl acetate to a solid content concentration of 20% by weight to produce the pressure-sensitive adhesive compositions of the examples and comparative examples. The content unit of each component in the table below is parts by weight based on 100 parts by weight of the acrylic copolymer.

[0133] (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 corona-discharge-treated iodine-based polarizing film was laminated as a base film onto the pressure-sensitive adhesive layer to produce a pressure-sensitive adhesive sheet.

[0134]

Table 1

[0135] The specific component names shown in Table 1 above are as follows. Acrylic Copolymer (A) A-1: The copolymer produced in Production Example 1 A-2: The copolymer produced in Production Example 2 A-3: The copolymer produced in Production Example 3 Crosslinking Agent (B) B-1: D-110N (xylene diisocyanate-based crosslinking agent, manufactured by Mitsui Chemicals, Inc.) B-2: Coronate-HXR (Hexamethylene diisocyanate-based crosslinking agent, manufactured by Nippon Polyurethane Industry Co., Ltd.) Organosilicon Compound (C) C-1: Methyl 3-oxo-((3-(3-trimethoxysilyl)propyl)amino)propanoate C-2: 3-((3-(Trimethoxysilyl)propyl)thio)propyl 3-oxobutanoate C-3: KBM-403 (3-Glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) Antistatic Agent (D) D-1: Compound represented by the following Chemical Formula 1-1 (ImC12-FSI, melting point: 35°C) JPEG2025111402000012.jpg5241D-2: Compound represented by the following Chemical Formula 1-2 (ImC14-FSI, melting point: 66°C) JPEG2025111402000013.jpg5243D-3: Compound represented by the following Chemical Formula 1-3 (ImC18-FSI, melting point: 48°C) JPEG2025111402000014.jpg5343D-4: Compound represented by the following Chemical Formula 1-4 (H-ImC14-FSI, melting point: 40°C) JPEG2025111402000015.jpg5242D-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 4

[0136] JPEG2025111402000016.jpg5442

[0137] 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, and after peeling off the release film, the exposed adhesive layer was attached to a glass substrate (#1737, manufactured by Corning) under 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.

[0138] To measure the room temperature adhesion, the test piece prepared above was left standing for 24 hours under the conditions of a temperature of 23°C and a relative humidity of 50%RH. Using a universal tensile testing machine (UTM, manufactured by Instron Corporation), 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 room temperature adhesion.

[0139] To measure the heat adhesion, the test piece prepared above was left standing for 48 hours under the conditions of a temperature of 50°C and a relative humidity of 50%RH. Thereafter, using a universal tensile testing machine (UTM, manufactured by Instron Corporation) under the conditions of a temperature of 23°C and a relative humidity of 50%RH, 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 heat adhesion.

[0140] (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, and after peeling off the release film, the exposed adhesive layer was attached to a glass substrate at a pressure of 0.25 MPa, and 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.

[0141] To measure the heat reworkability, the test piece prepared above was taken out after being left standing 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.

[0142] To measure the heat and humidity reworkability, the test piece prepared above was left standing in an oven at a temperature of 60°C and a relative humidity of 90%RH for 12 hours, stored at room temperature for 120 hours, and then the adhesive layer was peeled at a speed of 1.3 cm / sec.

[0143] <Evaluation criteria> ○: In both heat reworkability and heat and humidity reworkability, there is no remaining adhesive on the glass substrate, and the base film (polarizing film) is peeled off cleanly without being torn. ×: In any one or more of heat-resistant reworkability and heat and humidity-resistant reworkability, there is adhesive remaining on the glass substrate, or the base film (polarizing film) is torn during peeling.

[0144] (3) Evaluation of durability (heat resistance, heat and humidity resistance) 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 an autoclave treatment (50 °C × 30 minutes, 0.5 MPa) was performed to prepare test pieces. 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.

[0145] 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 heat and humidity 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, it was observed after leaving it at room temperature for 24 hours immediately before evaluating the state of the test piece.

[0146] <Evaluation criteria> ◎: No bubbles or peeling ○: Less than 5 bubbles or peeling △: 5 ≤ bubbles or peeling < 10 ×: 10 ≤ bubbles or peeling

[0147] (4) Measurement of adhesion The adhesive sheet manufactured above was cut into a size of 25 mm in length × 50 mm in width, and was attached to a SUS304 plate via a double-sided adhesive tape (width: 25 mm, manufactured by SOOKWANG) on the polarizing film 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 polarizing film was measured to judge the adhesion.

[0148] (5) Measurement of antistatic property The manufactured adhesive sheet was cut into a size of 200 mm in length and 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 2 below.

[0149] The adhesion ratio in Table 2 below means the ratio of the adhesion force at elevated temperature to the adhesion force at room temperature.

[0150]

Table 2

[0151] Referring to Table 2, the adhesive sheets of the examples were 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 sheets of the examples 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.

[0152] The adhesive sheet of Comparative Example 1 was formed from an adhesive composition that does not contain an antistatic agent. For this reason, the value of the surface resistivity increased and the antistatic property decreased significantly.

[0153] The adhesive sheets of Comparative Examples 2 and 3 were formed from an adhesive composition containing an organosilicon compound having no carbonyl group and an ionic antistatic agent having no imidazolium-based cation and bis(fluorosulfonyl)imide anion. For this reason, the adhesive sheets of Comparative Examples 2 and 3 had a surface resistivity value lower than that of the adhesive sheet of Comparative Example 1 but higher than that of the adhesive sheet of the example, and the antistatic property of the adhesive sheet was not sufficiently improved.

[0154] In addition, bubbles and / or peeling occurred in the adhesive sheets of Comparative Examples 2 and 3 in a high-temperature and high-humidity environment, and the durability of the adhesive sheets of Comparative Examples 2 and 3 in a harsh environment decreased.

[0155] The pressure-sensitive adhesive sheet of Comparative Example 4 was formed from a pressure-sensitive adhesive composition containing an ionic antistatic agent having no imidazolium-based cation and bisfluorosulfonylimide anion. For this reason, the durability in a harsh environment was deteriorated and the antistatic property was lowered as compared with Example 6.

[0156] The pressure-sensitive adhesive sheet of Comparative Example 5 was formed from a pressure-sensitive adhesive composition containing an organosilicon compound having no carbonyl group. For this reason, the reworkability was greatly deteriorated.

[0157] The pressure-sensitive adhesive sheet of Comparative Example 6 was formed from a pressure-sensitive adhesive composition containing an ionic antistatic agent having an imidazolium-based cation and hexafluorophosphate anion. For this reason, the antistatic property and the durability in a harsh environment were lowered.

[0158] The foregoing description is merely an exemplification applying the principle of the present invention, and other configurations can be further included without departing from the scope of the present invention.

Claims

1. An acrylic copolymer, a crosslinking agent, an organosilicon compound containing at least two or more carbonyl groups, and an ionic antistatic agent having an imidazolium cation and a bisfluorosulfonylimide anion, the pressure-sensitive adhesive composition.

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

3. The (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 according to claim 2.

4. 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, the pressure-sensitive adhesive composition according to claim 2.

5. The ionic antistatic agent includes an ionic compound represented by the following Chemical Formula 1, the pressure-sensitive adhesive composition according to claim 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.)

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

7. 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, the pressure-sensitive adhesive composition according to claim 1.

8. The organosilicon compound contains a nitrogen atom or a sulfur atom, the pressure-sensitive adhesive composition according to claim 1.

9. The organosilicon compound contains an amine group or a sulfide group, the pressure-sensitive adhesive composition according to claim 8.

10. The organosilicon compound has two carbonyl groups linked by a methylene group, the pressure-sensitive adhesive composition according to claim 1.

11. The organosilicon compound has a malonyl group or an acetoacetyl group, the pressure-sensitive adhesive composition according to claim 10.

12. The organosilicon compound includes a compound represented by the following Chemical Formula 2 or the following Chemical Formula 3, the pressure-sensitive adhesive composition according to claim 1. [Chemical 2] 【Chemical Formula 3】 (In the Chemical Formula 2 and the Chemical Formula 3, R ３ is an alkoxy group having 1 to 12 carbon atoms, and R ８ is an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms, and R ４ and R ９ are each independently a divalent aliphatic hydrocarbon group having 1 to 30 carbon atoms, R ５ ~R ７ and R １０ ~R １２ are each independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.

13. The content of the organosilicon compound 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 according to claim 1.

14. 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 according to claim 1.

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

16. A base film, A pressure-sensitive adhesive sheet including the base film and a pressure-sensitive adhesive layer disposed on the base film and formed using the pressure-sensitive adhesive composition according to claim 1.

17. The pressure-sensitive adhesive sheet according to claim 16, wherein the rate of change in adhesive strength of the pressure-sensitive adhesive sheet according to the following formula 2 is more than 1 and 1.7 or less. 【Number 1】 (In Formula 2, P Ｃ is the adhesive force measured by attaching the adhesive sheet to the object, leaving it for 24 hours under the conditions of a temperature of 23°C and a relative humidity of 50%, and then peeling the adhesive sheet from the object at a peeling speed of 300 mm / min and a peeling angle of 180°. P Ｈ is the adhesive force measured by attaching the adhesive sheet to the object, leaving it for 48 hours under the conditions of a temperature of 50°C and a relative humidity of 50%, and then peeling the adhesive sheet from the object at a peeling speed of 300 mm / min and a peeling angle of 180° under the conditions of a temperature of 23°C and a relative humidity of 50%.

18. The surface resistivity value of the adhesive layer is 5×10 １０ Ω / square or less. The adhesive sheet according to claim 16.

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

20. An image display device including the optical film according to claim 19.

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