Adhesive composition, adhesive layer formed using the same, adhesive film containing the adhesive layer

Abstract

The present invention relates to an adhesive composition comprising a urethane oligomer, an acrylate monomer, a plasticizer and a photoinitiator, the plasticizer having a weight average molecular weight (Mw) of 200 or more and contained in an amount of 0.5 to 10 parts by weight per 100 parts by weight of the total of the urethane oligomer and the acrylate monomer, an adhesive layer formed using the same, and an adhesive film comprising the adhesive layer, the adhesive composition having high adhesion to various substrates, excellent storage modulus and foldability at -30°C, and exhibiting excellent reliability even under harsh conditions of high temperature and high humidity.

Description

Technical Field

[0001] The present invention relates to an adhesive composition, an adhesive layer produced using the same, and an adhesive film including the adhesive layer.

Background Art

[0002] In the display industry, a number of optically transparent pressure-sensitive adhesives are used to mount a touch panel or a touch screen, or to obtain high brightness and high transmittance.

[0003] With the development of technology, touch screens or touch panels used in the display industry are gradually being switched to a foldable form, and the adhesives used to attach a transparent conductive film to such touch screens or touch panels require adhesiveness to various substrates, and at the same time, durability that can suppress the occurrence of curl, bubbles, etc., even when exposed to harsh conditions such as high temperature and high humidity conditions.

[0004] On the other hand, Korean Patent Publication No. 10-2013-0056587 discloses an adhesive composition for a touch panel including a urethane oligomer having a glass transition temperature of 50 to -60°C and a weight average molecular weight of 40,000 to 60,000. However, when the adhesive is used for a foldable display, there are problems such as the adhesive film breaking, lifting, or forming wrinkles, and there is also a problem of weak durability with less than a certain degree of curing.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention aims to improve upon the problems of the prior art described above and to provide an adhesive composition that is excellent in adhesion, low-temperature storage modulus, low-temperature folding properties, and high-temperature reliability.

[0007] Furthermore, the present invention aims to provide an adhesive layer formed using the aforementioned adhesive composition.

[0008] Furthermore, the present invention aims to provide an adhesive film including the adhesive layer. [Means for solving the problem]

[0009] The present invention provides an adhesive composition comprising a urethane oligomer, an acrylate monomer, a plasticizer, and a photoinitiator, wherein the plasticizer has a weight-average molecular weight (Mw) of 200 or more and is present in an amount of 0.5 to 10 parts by weight per 100 parts by weight of the total of the urethane oligomer and acrylate monomer.

[0010] Furthermore, the present invention provides an adhesive layer formed using the adhesive composition described above. Furthermore, the present invention provides an adhesive film including the adhesive layer. [Effects of the Invention]

[0011] The adhesive composition according to the present invention not only exhibits high adhesion to a variety of substrates, but the adhesive film containing the adhesive layer formed using it exhibits excellent storage modulus and folding properties at -30°C, and demonstrates reliable performance even under harsh conditions of high temperature and high humidity. [Modes for carrying out the invention]

[0012] The present invention relates to an adhesive composition comprising a urethane oligomer, an acrylate monomer, a plasticizer, and a photoinitiator, wherein the plasticizer has a weight-average molecular weight (Mw) of 200 or more and is present in an amount of 0.5 to 10 parts by weight per 100 parts by weight of the total of the urethane oligomer and acrylate monomer, an adhesive layer formed using the same, and an adhesive film containing the adhesive layer.

[0013] According to the present invention, it is possible to provide an adhesive composition, adhesive layer, and adhesive film that exhibit high adhesion to a variety of substrates, have excellent storage modulus and folding properties at -30°C, and are highly reliable even under harsh conditions of high temperature and high humidity.

[0014] The present invention will be described in detail below. <Adhesive composition> The adhesive composition according to the present invention comprises a urethane oligomer, an acrylate monomer, a plasticizer, and a photoinitiator, and may further contain additional components as long as they do not hinder the objectives of the present invention.

[0015] The glass transition temperature (Tg) of the adhesive composition of the present invention may be -70 to -20°C, and preferably -70 to -40°C. When the adhesive composition satisfies the above glass transition temperature range, it has the advantage of superior low-temperature folding characteristics.

[0016] Urethane oligomer In the present invention, the urethane oligomer plays a role in imparting the physical properties and flexibility of the adhesive composition and maintaining its viscoelasticity and storage modulus.

[0017] The urethane oligomer can be produced by known methods of polymerizing a polyol and a diisocyanate compound.

[0018] The polyol can produce an oligomer having an ether main chain by using a cyclic ether monomer such as an oxirane such as ethylene oxide, propylene oxide or tetrahydrofuran. Also, by using a cyclic ester such as ε-caprolactone or pivalolactone, an oligomer having an ester main chain can be produced.

[0019] The polyol may be a polyester polyol represented by the following Chemical Formula 1.

[0020]

Chem.

[0021] In Chemical Formula 1, R is an alkylene group having from 1 to 20 carbon atoms, preferably an alkylene group having from 1 to 10 carbon atoms.

[0022] Also, in Chemical Formula 1, n is an integer from 1 to 5, preferably an integer from 1 to 3.

[0023] Furthermore, in Chemical Formula 1, m is an integer from 0 to 5, preferably an integer from 0 to 3.

[0024] Examples of the compound represented by Chemical Formula 1 include, but are not limited to, polycaprolactone polyol obtained by ring-opening polymerization of a low molecular weight polyol and ε-caprolactone. <00001When the prepared polyol is reacted with a diisocyanate compound, a polyol structure having a urethane bonding group can be obtained. The diisocyanate compounds include 1,4-butylene diisocyanate, 1,6-hexamethylene diisocyanate, cyclopentylene-1,3-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, cyclohexene-1,4-diisocyanate, 2,4-tole diisocyanate, 2,6-tole diisocyanate, 4,4'-methylenebis(phenylisocyanate), and 2,2-diphenylpropane-4,4'-di Preferably, the compound contains an aliphatic diisocyanate compound selected from the group consisting of socianate, p-phenylenediisocyanate, m-phenylenediisocyanate, xylenediisocyanate, 1,4-naphthylenediisocyanate, 1,5-naphthylenediisocyanate, 4,4'-diphenyldiisocyanate, azobenzene-4,4'-diisocyanate, m- or p-tetramethylxylenediisocyanate, and 1-chlorobenzene-2,4-diisocyanate.

[0026] The urethane oligomer may contain at least one photoreactive functional group at its terminus. The presence of at least one photoreactive functional group at its terminus is preferable because it offers the advantage of superior properties in high-temperature, high-humidity reliability.

[0027] Examples of the photoreactive functional group include, but are not limited to, acrylate groups, acetophenone groups, benzoin groups, acylphosphine oxide groups, titanocene groups, benzophenone groups, anthracene groups, and thioxanthone groups. Preferably, one or more selected from the group consisting of acrylate groups, benzophenone groups, and benzoin groups.

[0028] The weight-average molecular weight (Mw) of the urethane oligomer may be 30,000 to 100,000, and preferably 50,000 to 90,000. When the urethane oligomer satisfies the weight-average molecular weight, it has the advantage of exhibiting better reliability under high temperature and high humidity conditions.

[0029] The urethane oligomer is present in an amount of 10 to 60% by weight, preferably 15 to 50% by weight, relative to the total weight of the urethane oligomer and acrylate monomer. When the urethane oligomer satisfies the above content range, it is preferable because it has the advantage of allowing appropriate adjustment of the balance between the viscosity and optical properties of the adhesive composition.

[0030] Acrylate monomer In the present invention, the acrylate monomer plays a role in providing durability while maintaining viscoelasticity and adjusting viscosity to improve the coatability of the adhesive composition.

[0031] The acrylate monomer may include one or more selected from the group consisting of (meth)acrylates having an alkyl group with 6 to 30 carbon atoms and (meth)acrylates having a polar group, and preferably may include all of the (meth)acrylates having an alkyl group with 6 to 30 carbon atoms and (meth)acrylates having a polar group. In this case, there is an advantage in that the folding properties at low temperatures can be improved.

[0032] The (meth)acrylate having an alkyl group having 6 to 30 carbon atoms is not particularly limited as long as it contains an alkyl group having 6 to 30 carbon atoms, and the term "(meth)acrylate" includes all acrylates and methacrylates.

[0033] Specific examples of the (meth)acrylate having an alkyl group with 6 to 30 carbon atoms include hexyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, n-octyl(meth)acrylate, isooctyl(meth)acrylate, n-nonyl(meth)acrylate, isononyl(meth)acrylate, n-decyl(meth)acrylate, isodecyl(meth)acrylate, n-dodecyl(meth)acrylate, n-tridecyl(meth)acrylate, and n-tetradecyl(meth)acrylate, which can be used individually or in combination of two or more. Preferably, it may contain 2-ethylhexyl acrylate.

[0034] The (meth)acrylate having the polar group is not particularly limited, but can include hydroxyalkyl (meth)acrylate, acrylamide, aminoalkyl (meth)acrylate, acrylic acid, methacrylic acid, etc. Preferably, it can include hydroxyalkyl (meth)acrylate.

[0035] The hydroxyalkyl (meth)acrylates mentioned above specifically include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl acrylate. It is preferable that these include one or more selected from 4-hydroxybutyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate.

[0036] The (meth)acrylate having polar groups is present in an amount of 3 to 30% by weight, preferably 5 to 20% by weight, relative to the total weight of the acrylate monomer. When the (meth)acrylate having polar groups satisfies the above content range, there is the advantage that the adhesive strength is improved and it can exhibit excellent reliability under high temperature and high humidity conditions.

[0037] The acrylate monomer is present in an amount of 40 to 90% by weight, preferably 50 to 80% by weight, relative to the total weight of the urethane oligomer and the acrylate monomer. When the acrylate monomer content satisfies the above range, there is an advantage in adjusting the viscosity and improving the coatability of the adhesive composition.

[0038] Furthermore, the urethane oligomer and acrylate monomer are included in a weight ratio of 1:9 to 5:5, preferably in a weight ratio of 2:8 to 4:6. When the urethane oligomer and acrylate monomer satisfy the above weight ratio, there is the advantage that the modulus of elasticity can be adjusted and the optimal point for low-temperature folding properties and reliability can be found.

[0039] plasticizer In the present invention, the plasticizer plays a role in improving the flexibility of the adhesive layer and adhesive film formed using the adhesive composition.

[0040] The aforementioned plasticizer is not particularly limited as long as it can be added to the adhesive composition to improve flexibility, but a plasticizer with a weight-average molecular weight (Mw) of 200 to 1500 can be used, preferably 200 to 1000, and more preferably 200 to 500. When the weight-average molecular weight of the plasticizer satisfies the above range, there is an advantage that it can exhibit better reliability under high temperature and high humidity conditions.

[0041] The plasticizer is, for example, DOP (dioctyl phthalate), DOA (dioctyl adipate), TCP (tricresyl phosphate), DIOP (diisooctyl phthalate), DINP (diisononyl phthalate), DUP (diunedecyl phthalate), BBP (butyl benzyl phthalate), DEHA (bis(2-ethylhexyl)adipate), DIDA (diisodecyl adipate), DOS (bis(2-ethylhexyl)sebacate), DIOZ (diisooctyl azelate), TOP (tri-2-ethylhexyl phosphate), TPP (triphenyl phosphate), CDP (cresyl diphenyl phosphate), TCP (tricresyl phosphate), TXP (trixylyl phosphate), TOTM (tri-2-ethylhexyl trimellitate), ASE (alkyl sulphonic acid phenyl ester), 3G6 (triethylene glycol dihexanoate), 4G7 (tetraethylene glycol diheptanoate), ATEC (acetyl triethyl citrate), TBC (tributyl citrate), TOC (trioctyl citrate), ATOC (acetyl trioctyl citrate), ATHC (acetyl trihexyl citrate), TMC (trimethyl citrate), DBM (dibutyl maleate), DIBM (diisobutyl maleate), BDNPF (bis(2,2-dinitropropyl)formal), TNEN (2,2,2-trinitroethyl 2-nitroxyethyl ether, polyethylene glycol ester, or a combination thereof can be used, preferably one or more selected from the group consisting of DOP (dioctyl phthalate), DOA (dioctyl adipate), and DIOP (diisooctyl phthalate), but not limited thereto.

[0042] The plasticizer is present in an amount of 0.5 to 10 parts by weight, preferably 1 to 8 parts by weight, per 100 parts by weight of the total amount of the urethane oligomer and acrylate monomer. When the plasticizer content range is satisfied, it has the advantage of improving the storage modulus properties at low temperatures and showing better reliability under high temperature and high humidity conditions.

[0043] Photoinitiator The adhesive composition of the present invention contains a photoinitiator. The photoinitiator is a compound that initiates a polymerization reaction and generates active radicals or acids upon the action of light. Any photoinitiator used in the art can be used without limitation.

[0044] Examples of photoinitiators of the present invention include benzoin compounds, benzophenone compounds, alkylphenone compounds, acylphosphine oxide compounds, triazine compounds, iodonium salts, and sulfonium salts.

[0045] Examples of benzoin compounds include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

[0046] Examples of benzophenone compounds include benzophenone, o-methyl benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone, and 2,4,6-trimethylbenzophenone.

[0047] Examples of alkylphenone compounds include diethoxyacetophenone, 2-methyl-2-morpholino-1-(4-methylthiophenyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]propan-1-one, 1-hydroxycyclohexylphenyl ketone, and oligomers of 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propan-1-one.

[0048] Examples of acylphosphine oxide compounds include 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0049] Examples of triazine compounds include 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxynaphthyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5-triazine, and 2,4-bis(trichloromethyl)-6-[2-(5-methylfuran-2-yl)ethenyl] Examples include -1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)ethenyl]-1,3,5-triazine, and 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)ethenyl]-1,3,5-triazine.

[0050] As the aforementioned photoinitiators, commercially available photopolymerization initiators such as Irgacure 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369 (all manufactured by Ciba Japan Co., Ltd.), SEIKUOL BZ, SEIKUOL Z, SEIKUOL BEE (all manufactured by Seiko Chemical Co., Ltd.), kayacure BP100 (manufactured by Nippon Kayaku Co., Ltd.), kayacure UVI-6992 (manufactured by Dow Corporation), ADEKA optomer SP-152 or ADEKA optomer SP-170 (both manufactured by ADEKA Corporation), TAZ-A, TAZ-PP (both manufactured by Nippon Siber Hegner Ltd.), and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.) can also be used.

[0051] The photoinitiator is present in an amount of 0.01 to 3 parts by weight, preferably 0.1 to 2 parts by weight, per 100 parts by weight of the total amount of the urethane oligomer and acrylate monomer. When the photoinitiator satisfies the above content range, there is an advantage that sufficient polymerization reaction of the adhesive composition can be carried out to ensure the cohesive strength of the adhesive layer formed.

[0052] <Adhesive layer, adhesive film, and methods for manufacturing the same> Furthermore, the present invention provides an adhesive layer formed using the above-described adhesive composition, an adhesive film containing the same, and a method for producing the same.

[0053] The adhesive layer can be formed by curing the adhesive composition of the present invention. Furthermore, an adhesive film can be manufactured comprising a transparent substrate film and the adhesive layer formed on at least one surface of the transparent substrate film.

[0054] The thickness of the adhesive layer may be 25 to 1000 μm. The transparent substrate film may be, but is not limited to, one that is excellent in terms of transparency, mechanical strength, thermal stability, moisture shielding properties, isotropy, etc.

[0055] The curing method is not particularly limited as long as it is used in this field, but photocuring using ultraviolet light is common.

[0056] During polymerization using ultraviolet light, the light source has a wavelength of 400 nm or less, preferably 150 to 400 nm, and more preferably 200 to 380 nm. Examples of such light sources include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps.

[0057] The intensity of the light irradiation can be appropriately adjusted according to the required properties of the adhesive, and the cumulative light amount useful for activating the free radical photoinitiator is 10 to 5000 mJ / cm². 2 Preferably, the concentration is 200-2000 mJ / cm². 2 This is more preferable. It is preferable because it has an appropriate curing reaction time within the above range and does not cause a decrease in the cohesive strength, yellowing, or deterioration of the support of the cured product due to the heat radiated from the lamp and the heat generated during the polymerization reaction.

[0058] The following describes specific embodiments for carrying out the present invention. However, the present invention is not limited to the following and can be modified as appropriate to the extent necessary in the ordinary art. [Examples]

[0059] Manufacturing example: Manufacturing of urethane oligomers Manufacturing Example 1 An isocyanate polymer was obtained by reacting 81 parts by weight of polycaprolactone diol (trade name: Placel212, manufactured by Daicel Chemical Industries, Ltd.) with 500 ppm dibutyltin dilaurate catalyst (DBTDL) and 10 parts by weight of isophorone diisocyanate at 80°C, and then reacting the resulting isocyanate polymer with 9 parts by weight of hydroxyethyl acrylate to produce a urethane acrylate oligomer with a weight-average molecular weight of 60,000.

[0060] Manufacturing Example 2 An isocyanate polymer was obtained by reacting 81 parts by weight of polycaprolactone diol (product name: Placel220, manufactured by Daicel Chemical Industries, Ltd.) with 500 ppm dibutyltin dilaurate catalyst (DBTDL) and 10 parts by weight of isophorone diisocyanate at 80°C, and then reacting the resulting isocyanate polymer with 9 parts by weight of hydroxyethyl acrylate to produce a urethane acrylate oligomer with a weight-average molecular weight of 80,000.

[0061] Examples and Comparative Examples: Manufacturing of Adhesive Compositions and Adhesive Films (1) Adhesive composition Adhesive compositions were prepared according to the components and their contents shown in Table 1 below. The glass transition temperature (Tg) of each adhesive composition was measured using a measuring device (DSC8000, PerkinElmer), and the results are shown in Table 1 below.

[0062] [Table 1]

[0063] 2-EHA:2-Ethylhexylacrylate 4-HBA:4-hydroxybutyl acrylate 2-HEA:2-hydroxyethyl acrylate DOA: Dioctyl Adipate (Mw: 370) DOP: Dioctyl phthalate (Mw: 390) DMAD: Dimethyl adipate (Mw: 174) I-184: Irgacure 184 (manufactured by Chiba Japan Co., Ltd.) (2) Adhesive film The adhesive composition produced in (1) above was coated onto a polyethylene phthalate film (thickness: 75 μm) that had been treated with a coating liquid release agent using a bar coater. Thereafter, the film was cured by irradiating it with ultraviolet light using a UV lamp for 10 minutes, and an adhesive film was produced such that the thickness of the adhesive composition after curing was 50 μm.

[0064] Experimental example (1) Measurement of the storage modulus The storage modulus of the manufactured adhesive film was measured using a viscoelasticity measuring device (MCR-301, Anton Paar). More specifically, the adhesive film was cut to a size of 30 mm in length and 30 mm in width. After removing the release film attached to one side of the cut adhesive film, it was bonded to a glass substrate. Then, with the film attached to a measuring tip, the storage modulus was measured in the temperature range of -30 to 100°C under conditions of a frequency of 1.0 Hz, a deformation of 2%, and a heating rate of 5°C / min. The measurement value at -30°C was read, and the measurement results are shown in Table 2 below.

[0065] (2) Folding ability evaluation The manufactured adhesive film was bonded to a 50 μm PET sheet, cut into pieces measuring 20 mm in length and 100 mm in width, and used as test specimens.

[0066] The test specimen was fixed to a flexibility evaluation device (COVOTECH, CFT-720C) for evaluating folding properties, and folded to a radius of curvature of 2 mm. The folding evaluation was performed at -30°C under conditions of 25 folding cycles per minute, with a 0.2-second hold after each folding cycle. When applying the folding evaluation, one folding cycle was defined as one cycle. The number of cycles in which stripes or other patterns appeared at the folded area, or when the adhesive film broke, lifted, or peeled, was evaluated. If stripes or other patterns appeared at the folded area, or when the adhesive film broke, lifted, or peeled, it was judged as NG; if none occurred, it was judged as OK. The results are shown in Table 2 below.

[0067] (3) High-temperature reliability evaluation The manufactured adhesive film was positioned and bonded between the polarizing plate and the PET, then cut to 200mm x 300mm, stored for 10 days under high temperature and high humidity conditions (85°C, 85% relative humidity), and then observed visually to check for the presence or absence of bubbles. The high-temperature reliability was evaluated according to the evaluation criteria below. The results are shown in Table 2 below.

[0068] <Evaluation Criteria> ◎: No bubbles or peeling. ○: One to less than five bubbles or delaminations. △: 5 to 10 bubbles or delaminations ×: More than 10 bubbles or peeling

[0069] [Table 2]

[0070] Referring to Table 2 above, it can be confirmed that the adhesive films produced using the adhesive compositions according to Examples 1 to 4 of the present invention all show excellent results in storage modulus and folding performance evaluation at -30°C, as well as in high-temperature reliability evaluation.

[0071] In contrast, in Comparative Example 1, which uses a plasticizer with a weight-average molecular weight of less than 200, and Comparative Example 2, which contains a plasticizer in excess of the appropriate amount, the evaluation results of the storage modulus at -30°C and / or high-temperature reliability were significantly reduced. In Comparative Example 3, which does not contain a plasticizer, the evaluation results of the storage modulus at -30°C and folding properties were also significantly reduced.

Claims

1. The mixture contains a urethane oligomer, an acrylate monomer, a plasticizer, and a photoinitiator. The acrylate monomer includes a (meth)acrylate having an alkyl group having 6 to 30 carbon atoms and a (meth)acrylate having a polar group. The plasticizer has a weight-average molecular weight (Mw) of 200 or more and comprises one or more selected from the group consisting of dioctyl phthalate (DOP) and dioctyl adipate (DOA), and is present in an amount of 0.5 to 10 parts by weight per 100 parts by weight of the total of the urethane oligomer and acrylate monomer. The aforementioned urethane oligomer has the following chemical formula 1: 【Chemistry 1】 (In the above chemical formula 1, R is an alkylene group having 1 to 20 carbon atoms. n is an integer between 1 and 5. m is an integer between 0 and 5. An adhesive composition which is polymerized containing a compound represented by [the formula shown].

2. The adhesive composition according to claim 1, wherein the plasticizer has a weight-average molecular weight (Mw) of 200 to 1500.

3. The adhesive composition according to claim 1, wherein the (meth)acrylate having the polar group is present in an amount of 3 to 30% by weight relative to the total weight of the acrylate monomer.

4. The adhesive composition according to claim 1, wherein the urethane oligomer and acrylate monomer are contained in a weight ratio of 1:9 to 5:

5.

5. An adhesive layer formed using the adhesive composition according to any one of claims 1 to 4.

6. An adhesive film comprising the adhesive layer described in claim 5.

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