Curable composition

Abstract

The present application relates to a curable composition and can provide a curable composition capable of producing an adhesive that can be bent well on curved or deformable parts, has excellent recovery characteristics to its original state so that there are no defects after recovery, and is easy to work with and cut. The present application can also provide a curable composition capable of producing an adhesive that laminates without lifting on curved parts during the lamination process and has excellent step-filling properties.

Description

Technology Field

[0001] This application relates to a curable composition. Background Technology

[0002] The display market is rapidly shifting toward flat-panel displays, which facilitate large-area applications and enable thin and lightweight designs. Representative examples of such flat-panel displays include Liquid Crystal Displays (LCDs) and Organic Light Emitting Displays (OLEDs).

[0003] Recently, new types of display devices are being researched and developed by applying flexible substrates, such as plastic, to flat panel displays as described above. These display devices include flexible displays such as curved displays, foldable displays, or rollable displays, in which the display panel is bent into a curved shape.

[0004] Meanwhile, an adhesive may be used to bond together configurations having curved portions included in a curved display or deformable configurations included in a foldable or rollable display, or to fill the internal space of the display.

[0005] It is advantageous for these adhesives to exhibit a low elastic modulus and a high creep strain at room temperature to ensure they can be bent well in curved, folding, or rolling areas. Additionally, it is beneficial for them to possess a high elastic modulus and a high recovery rate at room temperature to ensure they recover well to their original state after bending. However, adhesives exhibiting a low elastic modulus at room temperature may have poor cutability and workability, while adhesives exhibiting a high elastic modulus may suffer from reduced step-filling ability to fill the internal space of a display. Furthermore, since it is required for the adhesive to exhibit a low elastic modulus and a high creep strain within the autoclave process temperature range (40–60°C) to ensure lamination without lifting on curved areas during the lamination process, balancing the aforementioned characteristics required for the adhesive is very difficult.

[0006] For manufacturing a pressure-sensitive adhesive that embodies all of the above characteristics, it is advantageous for the curable composition to have a low crosslinking density, a high glass transition temperature, and a low molecular weight of the resin component constituting the curable composition. However, since it is difficult to ensure that a curable composition prepared with a low molecular weight resin component possesses both a high glass transition temperature and low crosslinking density characteristics, manufacturing a pressure-sensitive adhesive that satisfies all of the above characteristics is a very difficult problem. The problem to be solved

[0007] The present application relates to a curable composition. The purpose of the present application is to provide a curable composition capable of producing an adhesive that deforms well in curved areas and areas subject to repeated deformation, has excellent recovery power, and is free of defects even after recovery.

[0008] In addition, the present application aims to provide a curable composition capable of producing an adhesive that is easy to cut and work with.

[0009] In addition, the present application aims to provide a curable composition capable of producing an adhesive that is laminated without lifting on curved surfaces and has excellent step-filling properties.

[0010] In addition, the present application also aims to provide a curved display or a flexible display comprising the above-mentioned curable composition or an adhesive that is a cured product thereof. means of solving the problem

[0011] Among the physical properties mentioned in this specification, if the measurement temperature affects the property, the property is the property measured at room temperature unless specifically otherwise specified.

[0012] In this specification, the term "room temperature" refers to a temperature in a state that is not specifically heated or cooled, and may mean any temperature within the range of about 10°C to 30°C, for example, about 15°C or higher, 18°C ​​or higher, 20°C or higher, or about 23°C or higher and about 27°C or lower. Additionally, unless specifically otherwise specified, the unit of temperature referred to in this specification is °C.

[0013] Among the physical properties mentioned in this specification, if the measured pressure affects the property, the property is the property measured at atmospheric pressure.

[0014] In this specification, the term atmospheric pressure refers to pressure in a state that is not specifically pressurized or depressurized, and means a pressure of about 1 atmosphere, which is the level of normal atmospheric pressure.

[0015] Among the physical properties mentioned in this specification, unless otherwise specifically defined where the measured humidity affects the property, said physical property is the property measured at natural humidity at the above-mentioned room temperature and pressure conditions.

[0016] This application relates to curable compositions. In one example, the curable composition of this application may be an adhesive composition. The term adhesive composition means a composition capable of forming an adhesive before or after curing. In one example, the adhesive composition of this application may be used as an Optically Clear Adhesive (OCA) or an Optically Clear Resin (OCR).

[0017] Adhesives applied to curved displays and flexible displays are required to deform well in curved areas or deformable areas (folding or rolling areas) and to have excellent recovery after deformation. In addition, while ensuring excellent cutability and workability, the adhesive is required to have excellent lamination characteristics on curved surfaces during the lamination process so that lamination can be performed without lifting and to have excellent step-filling properties.

[0018] As mentioned above, in order for deformation to occur effectively in curved or deformable areas, it is advantageous to exhibit a low elastic modulus and a high creep strain at room temperature. Additionally, it is advantageous to possess a high elastic modulus and high recovery capacity to ensure good recovery to the original state after deformation. However, since adhesives with low elasticity at room temperature can reduce cutting and workability, and adhesives with high elasticity at room temperature have poor step-filling capabilities, it is very difficult to manufacture an adhesive with desired physical properties by adjusting the balance of these conflicting characteristics.

[0019] For manufacturing an adhesive that embodies all these characteristics, it is advantageous for the curable composition to have a low crosslinking density, a high glass transition temperature, and a low molecular weight of the resin component (polymer component) constituting the curable composition. However, it is very difficult to simultaneously lower the molecular weight of the polymer component, increase the glass transition temperature of the curable composition, and lower the crosslinking density. Consequently, if the adhesive produced from the curable composition becomes excessively hard, it may result in poor step-filling performance and lamination characteristics on curved surfaces; conversely, if the adhesive becomes excessively soft, it may lead to lifting, delamination, cohesive failure, and / or bubble formation on curved surfaces, or result in reduced recovery ability.

[0020] The curable composition according to the present application described below can provide an adhesive that deforms well on curved surfaces and areas subject to repeated deformation, has excellent recovery after deformation, and is free of defects even after recovery. In addition, the curable composition of the present application can provide an adhesive that ensures excellent workability and cutting ability, while being laminated without lifting on curved surfaces and having excellent step-filling ability.

[0022] The curable composition of the present application may have a glass transition temperature of -10°C or higher. The glass transition temperature of the present application is measured according to a measurement method using conventional Differential Scanning Calorimeter (DSC) equipment, specifically by the glass transition temperature measurement method of the examples described below.

[0023] The curable composition of the present application may be a curable composition that can be manufactured into an adhesive by undergoing secondary curing (post-curing) after primary curing, as described below.

[0024] In one example, the glass transition temperature of a curable composition in this application may refer to the glass transition temperature of a curable composition after primary curing, and may refer to the glass transition temperature of a curable composition in a state where secondary curing is possible thereafter.

[0025] Specifically, the glass transition temperature of the curable composition of the present application may be -9°C or higher, -8°C or higher, -7°C or higher, -6°C or higher, -5°C or higher, -4°C or higher, -3°C or higher, -2°C or higher, -1°C or higher, 0°C or higher, 1°C or higher, 2°C or higher, 3°C or higher, 4°C or higher, 5°C or higher, or 6°C or higher. The upper limit of the glass transition temperature of the curable composition of the present application is not limited, but may be 10°C or lower, 8°C or lower, 6°C or lower, 4°C or lower, 2°C or lower, 0°C or lower, or -2°C or lower.

[0026] The curable composition of the present application may have a storage modulus of 60,000 Pa or more at 25°C. Specifically, the storage modulus of the curable composition of the present application at 25°C is 63,000 Pa or more, 65,000 Pa or more, 67,000 Pa or more, 69,000 Pa or more, 71,000 Pa or more, 73,000 Pa or more, 75,000 Pa or more, 77,000 Pa or more, 80,000 Pa or more, 82,000 Pa or more, 84,000 Pa or more, 86,000 Pa or more, 88,000 Pa or more, 90,000 Pa or more, 92,000 Pa or more, 94,000 Pa or more, 96,000 Pa or more, 98,000 Pa or more, 100,000 Pa or more, 102,000 Pa or more, 104,000 Pa or more, 106,000 Pa or more, It may be 108,000 Pa or more, 110,000 Pa or more, 112,000 Pa or more, 114,000 Pa or more, 116,000 Pa or more, 118,000 Pa or more, 120,000 Pa or more, 122,000 Pa or more, or 124,000 Pa or more. The upper limit of the storage modulus at 25°C is not specifically limited, but may be 150,000 Pa or less, 130,000 Pa or less, 110,000 Pa or less, 90,000 Pa or less, 70,000 Pa or less, or 65,000 Pa or less. In this application, the storage modulus at 25°C is measured by the measurement method of the following example under conditions of 10% strain and a frequency of 1 rad / sce.

[0027] An adhesive prepared from a curable composition having a glass transition temperature in the above range and a storage modulus value at 25°C can be bent well in curved, folding, or rolling parts of a display, has excellent recovery characteristics to its original state so that there are no defects after recovery, and has the advantage of being easy to work with and cut.

[0028] The curable composition of the present application may have a creep strain of 80% or more at 50°C. Specifically, the creep strain of the curable composition at 50°C may be 85% or more, 90% or more, 95% or more, 100% or more, 105% or more, 110% or more, 115% or more, 120% or more, 125% or more, 130% or more, 135% or more, 140% or more, 145% or more, 150% or more, 155% or more, 160% or more, or 165% or more. The upper limit of the creep strain at 50°C may be, for example, 200% or less, 190% or less, 180% or less, 170% or less, 160% or less, 150% or less, 140% or less, 130% or less, 120% or less, 110% or less, 100% or less, 90% or less, or 85% or less.

[0029] An adhesive prepared with the curable composition of the present application having a creep strain value in the above range at 50°C can be laminated on curved surfaces without lifting in an autoclave process temperature range (40 to 60°C), and can have the characteristics of not generating bubbles and having excellent step-filling ability.

[0030] The curable composition of the present application satisfies a change rate △G of gel content according to Formula 1 below of 10% or more. Specifically, the change rate (△G) of gel content of the curable composition may be 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, or 40% or more, or 50% or less, 45% or less, 40% or less, 35% or less, or 30% or less.

[0031] [Equation 1]

[0032] ΔG = 100 × (Ga-Gi) / Gi

[0033] In Equation 1, Ga is 3 J / cm² of ultraviolet light with a wavelength of 340 nm. 2 It is the gel content after irradiating the curable composition with the light intensity, and Gi is 3 J / cm² of ultraviolet light with a wavelength of 340 nm.2 It is the gel content before irradiating the above curable composition with the amount of light.

[0034] In the above Equation 1, the gel content can be measured by the gel content measurement method in the example described later.

[0035] The degree of crosslinking after curing of the curable composition can be expressed by the gel content. The curable composition of the present application may undergo secondary curing (post-curing) after primary curing. The gel content of the curable composition after secondary curing (post-curing) may increase by 10% or more compared to the gel content of the curable composition after primary curing. As described above, the adhesive prepared by undergoing a secondary curing process after primary curing of the curable composition has a higher crosslinking density and can exhibit the glass transition temperature value and the storage modulus value at 25°C described above to achieve the purpose of the present application.

[0036] In one embodiment of the present application, the gel content Gi of the curable composition may be in the range of 30% to 65%. Specifically, the gel content Gi of the curable composition may be 33% or more, 36% or more, 39% or more, 42% or more, 45% or more, 48% or more, 51% or more, or 53% or more, or 62% or less, 59% or less, 56% or less, 53% or less, 50% or less, 47% or less, 44% or less, or 42% or less.

[0037] The above gel content Gi may be the gel content of the curable composition after the first curing of the curable composition. The above first curing may be photocuring, and may be the gel content of the curable composition after the first photocuring using an ultraviolet lamp, for example, a black light ultraviolet lamp. During the first photocuring, it may be achieved by irradiating ultraviolet light with a wavelength range of 340 to 400 nm, preferably with a wavelength range including 365 nm. In addition, the ultraviolet light may be irradiated at approximately 0.1 J / cm² 2 Up to 3J / cm 2With a light intensity of, preferably 1 J / cm² 2 with the amount of light It can be achieved through investigation.

[0038] In one embodiment of the present application, the gel content Ga of the curable composition may be in the range of 40% to 90%. Specifically, the gel content Ga of the curable composition may be 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, or 70% or more, or 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, or 60% or less.

[0039] The gel content Ga mentioned above may be the gel content after the primary cured curable composition has undergone secondary curing. The secondary curing may be photocuring, and may be the gel content of the curable composition after secondary photocuring using a metal halide ultraviolet lamp or a mercury ultraviolet lamp. The secondary photocuring may be achieved by irradiating ultraviolet light with a wavelength range of approximately 315 nm to 420 nm, and preferably by irradiating ultraviolet light with a wavelength range including 340 nm. Additionally, the ultraviolet light has a wavelength of approximately 2 J / cm² 2 Up to 10 J / cm 2 It can be irradiated with a light intensity of 3J / cm². 2 It can be irradiated with the amount of light.

[0040] The curable composition of the present application may have a change rate △M1 of the storage modulus according to Formula 2 below of 45% or more.

[0041] [Equation 2]

[0042] ΔM1 = 100 × (M25-M50) / M25

[0043] In Equation 2, M25 is the storage modulus of the curable composition at 25°C, and M50 is the storage modulus of the curable composition at 50°C.

[0044] Specifically, the rate of change △M1 of the storage modulus according to the above Equation 2 may be 48% or more, 50% or more, 52% or more, 54% or more, 56% or more, 58% or more, 60% or more, 62% or more, 64% or more, 66% or more, or 68% or more, or 80% or less, 78% or less, 76% or less, 74% or less, 72% or less, 70% or less, 68% or less, 66% or less, 64% or less, 62% or less, 60% or less, 58% or less, 56% or less, 54% or less, or 52% or less.

[0045] In the above Equation 2, the storage modulus value M25 of the curable composition at 25°C can be 60,000 Pa or more as described above.

[0046] In addition, the storage modulus value M50 of the curable composition at 50°C may be 16,000 Pa or more, 18,000 Pa or more, 20,000 Pa or more, 22,000 Pa or more, 24,000 Pa or more, 26,000 Pa or more, 28,000 Pa or more, 30,000 Pa or more, 32,000 Pa or more, 34,000 Pa or more, 36,000 Pa or more, or 38,000 Pa or more, or 50,000 Pa or less, 45,000 Pa or less, 40,000 Pa or less, 35,000 Pa or less, 30,000 Pa or less, 25,000 Pa or less, or 20,000 Pa or less. In this application, the storage modulus at 50°C was measured by the measurement method of the following example under conditions of 10% strain and a frequency of 1 rad / sce.

[0047] The curable composition of the present application has the following characteristics: the rate of change △M1 of the storage modulus according to Formula 2 has the above range, so that it can be laminated on curved parts without lifting in the autoclave process temperature range (40~60℃), no bubbles are generated, and it has excellent step-filling properties.

[0048] The curable composition of the present application may have a rate of change ΔM2 of storage modulus according to Formula 3 below of 45% or more.

[0049] [Equation 3]

[0050] ΔM2 = 100 × (M50-M85) / M50

[0051] In Equation 3, M50 is the storage modulus of the curable composition at 50°C, and M85 is the storage modulus of the curable composition at 85°C.

[0052] Specifically, the rate of change ΔM2 of the storage modulus according to Equation 3 above may be 48% or more, 50% or more, 52% or more, 54% or more, 56% or more, 58% or more, 60% or more, 62% or more, 64% or more, 66% or more, or 68% or more, or 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, or 58% or less.

[0053] In the above Equation 3, the storage modulus value M50 of the curable composition at 50°C may be 16,000 Pa or more, 18,000 Pa or more, 20,000 Pa or more, 22,000 Pa or more, 24,000 Pa or more, 26,000 Pa or more, 28,000 Pa or more, 30,000 Pa or more, 32,000 Pa or more, 34,000 Pa or more, 36,000 Pa or more, or 38,000 Pa or more, or 50,000 Pa or less, 45,000 Pa or less, 40,000 Pa or less, 35,000 Pa or less, 30,000 Pa or less, 25,000 Pa or less, or 20,000 Pa or less.

[0054] In addition, the storage modulus value M85 of the curable composition at 85°C is 20,000 Pa or less, 18,000 Pa or less, 16,000 Pa or less, 14,000 Pa or less, 12,000 Pa or less, 10,000 Pa or less, or 8,000 Pa or less, or 6,000 Pa or more, 6,500 Pa or more, 7,000 Pa or more, 7,500 Pa or more, 8,000 Pa or more, 8,500 Pa or more, 9,000 Pa or more, 9,500 Pa or more, 10,000 Pa or more, 10,500 Pa or more, 11,000 Pa or more, 11,500 Pa or more, 12,000 Pa or more, 12,500 Pa or more, 13,000 Pa or more, 13,500 Pa or more, It may be 14,000 Pa or more, 14,500 Pa or more, 15,000 Pa or more, or 15,500 Pa or more. The storage modulus at 85°C above was measured by the measurement method of the following example under conditions of 10% strain and a frequency of 1 rad / sce.

[0055] Typically, a curable composition or its cured product tends to decrease in storage modulus as the temperature increases, but it is not easy to increase the rate of decrease. Since the curable composition or its cured product of the present application has a large rate of decrease in storage modulus as the temperature increases, it can be laminated on curved surfaces without lifting in the autoclave process temperature range (40 to 60°C), and can have the characteristics of not generating bubbles and having excellent step-filling properties.

[0056] The curable composition of the present application may have a recovery rate of 40 to 90% at 50°C. Specifically, the curable composition of the present application may have a recovery rate of 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, or 75% or more, or 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, or 60% or less.

[0057] The curable composition of the present application may have a light transmittance of about 80% or more and a haze of 2% or less according to the measurement conditions of ASTM D1003 after first curing. Specifically, the curable composition may have a light transmittance of about 82% or more, 85% or more, 88% or more, 90% or more, or 92% or more after first curing, and may have a light transmittance of about 95% or less, 94% or less, 93% or less, or 92% or less. Additionally, specifically, the curable composition may have a haze of about 1.8% or less, 1.5% or less, 1.2% or less, 1% or less, 0.8% or less, about 0.7% or less, about 0.6% or less, about 0.5% or less, about 0.4% or less, or about 0.3% or less, or 0.05% or more, 0.1% or more, 0.3% or more, 0.5% or more, 0.7% or more, 0.9% or more, 1.1% or more, 1.3% or more, 1.5% or more, 1.7% or more, or 1.9% or more.

[0058] In addition, the curable composition of the present application may have a color difference (b*) of 1 or less when measured with a Lab colorimeter after primary curing. Specifically, the color difference may be 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, 0.4 or less, or 0.3 or less, or 0.05 or more, 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, or 0.8 or more.

[0059] The curable composition of the present application may have a light transmittance of about 80% or more and a haze of 2% or less according to the measurement conditions of ASTM D1003 after secondary curing. Specifically, the curable composition may have a light transmittance of about 82% or more, 85% or more, 88% or more, 90% or more, or 92% or more after secondary curing, and may have a light transmittance of about 95% or less, 94% or less, 93% or less, or 92% or less. Additionally, specifically, the curable composition may have a haze of about 1.8% or less, 1.5% or less, 1.2% or less, 1% or less, 0.8% or less, about 0.7% or less, about 0.6% or less, about 0.5% or less, about 0.4% or less, or about 0.3% or less, or 0.05% or more, 0.1% or more, 0.3% or more, 0.5% or more, 0.7% or more, 0.9% or more, 1.1% or more, 1.3% or more, 1.5% or more, or 1.7% or more after secondary curing.

[0060] In addition, the curable composition of the present application may have a color difference (b*) of 1.2 or less when measured with a Lab colorimeter after primary curing. Specifically, the color difference may be 1.1 or less, 1 or less, 0.9 or less, 0.8 or less, or 0.7 or less, or 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, or 1 or more.

[0061] The adhesive prepared after secondary curing of the curable composition of the present application has excellent optical properties, including very high light transmittance, low haze, and low color difference. In addition, there is an advantage of being able to achieve excellent color reproduction, as there is little to no change in the optical properties of the curable composition even after secondary UV irradiation.

[0063] The curable composition of the present invention may be a solvent-free curable composition, and the adhesive prepared from the solvent-free curable composition may be a solvent-free adhesive. In the above, the term "solvent-free curable composition" refers to a curable composition that substantially does not contain solvents (aqueous solvents and organic solvents). Accordingly, the content of aqueous and organic solvents in the curable composition may be 1 weight% or less, 0.5 weight% or less, or 0.1 weight% or less, or substantially 0 weight%. Furthermore, the term "solvent-free adhesive" refers to an adhesive that contains the solvent-free curable composition as is or contains a cured product thereof.

[0064] To achieve the above-described properties, the curable composition of the present application may include a polymer component comprising an alkyl acrylate unit having a straight-chain or branched-chain alkyl group, a methacrylate unit, and a unit of the following chemical formula 1.

[0065] The polymer component included in the curable composition may be a syrup component. The syrup component may include a monomer component and an oligomer or polymer component formed by polymerizing two or more monomers. In one example, such a syrup component may be formed by so-called partial polymerization. That is, if a monomer composition according to the desired composition is partially polymerized, some monomers may polymerize to form the oligomer or polymer, while the remaining monomers may remain to form the syrup component. Accordingly, the term monomer unit, such as an acrylate unit, described below in this specification may refer to a monomer existing within the polymer component in a state of having formed the oligomer or polymer, or a monomer included within the syrup component without being polymerized.

[0066] The polymer component may include an alkyl acrylate unit having a straight-chain or branched-chain alkyl group. The alkyl group included in the unit may be an alkyl group having 4 to 20 carbon atoms. In other examples, the number of carbon atoms of the alkyl group may be 16 or fewer, 12 or fewer, or 8 or fewer, and may be substituted or unsubstituted.

[0067] As for the above alkyl acrylate, alkyl acrylate units having such straight-chain or branched-chain alkyl groups may be included in the polymer component in an amount of about 30 to 70 weight%. In other examples, the above ratio may be 35 weight% or more, 38 weight% or more, 40 weight% or more, 42 weight% or more, 44 weight% or more, 46 weight% or more, 48 weight% or more, 50 weight% or more, 52 weight% or more, or 54 weight% or more, or 65 weight% or less, 60 weight% or less, 55 weight% or less, 50 weight% or less, 45 weight% or less, or 42 weight% or less. The curable composition of the present application may include alkyl acrylate units having straight-chain or branched-chain alkyl groups in the above ranges to satisfy the ranges of glass transition temperature values, storage modulus values ​​at 25°C, and creep strain values ​​at 50°C of the curable composition as described above.

[0068] The polymer component may include a methacrylate unit. Specifically, the methacrylate unit may include an alkyl methacrylate unit comprising an alkyl group having 1 to 20 carbon atoms. In other examples, the alkyl group may be an alkyl group having 2 to 20 carbon atoms, 2 to 18 carbon atoms, 4 to 16 carbon atoms, 4 to 12 carbon atoms, or 4 to 8 carbon atoms. The alkyl group may be a straight chain or a branched chain, and may be substituted or unsubstituted.

[0069] The above polymer component may also include a unit of the following chemical formula 1 as a monomer unit.

[0070] [Chemical Formula 1]

[0071]

[0072] In Chemical Formula 1, R is hydrogen or a methyl group, and R1 and R2 are each independently hydrogen, an alkyl group, an alkoxy group, an aryl group, or an aralkyl group.

[0073] In Chemical Formula 1, the alkyl group or alkoxy group may mean a straight-chain or branched-chain alkyl group or alkoxy group having 1 to 20 carbon atoms, 1 to 18 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms.

[0074] In Chemical Formula 1, the aryl group may represent a compound having a benzene structure, a compound having a structure in which two or more benzenes are connected by a linker, a compound having a structure in which two benzenes are condensed or bonded while each sharing one or two carbon atoms, or a monovalent residue derived from a derivative of any one of the aforementioned compounds. The aralkyl group is a substituent in which one or more hydrogen atoms of the alkyl group are substituted with an aryl group.

[0075] The above aryl group may be an aryl group having 6 to 25 carbon atoms, 6 to 21 carbon atoms, 6 to 18 carbon atoms, or 6 to 12 carbon atoms. Examples of aryl groups may include a phenyl group, dichlorophenyl, chlorophenyl, phenylethyl group, phenylpropyl group, benzyl group, tolyl group, xylyl group, or naphthyl group.

[0076] The unit of the above chemical formula 1 may mean a unit that is polymerized within the polymer component and included in the form of chemical formula 1, or a monomer unit that is pre-polymerized and can form the form of chemical formula 1 when polymerized.

[0077] The above polymer component may additionally include a unit of the following chemical formula 2.

[0078] [Chemical Formula 2]

[0079]

[0080] In Chemical Formula 2, R is hydrogen or an alkyl group, and P is a monovalent substituent with a non-aromatic ring structure having 3 to 20 carbon atoms.

[0081] In the unit of Chemical Formula 2 above, the monovalent substituent having a non-aromatic ring structure may be a monovalent substituent having 3 to 20 carbon atoms, 6 to 15 carbon atoms, or 8 to 12 carbon atoms. Examples of the monovalent substituents may include an isobornyl group, a cyclohexyl group, a norbornenyl group, a norbornenyl group, a dicyclopentadienyl group, an ethynylcyclohexane group, an ethynylcyclohexene group, or an ethynyldecahydronaphthalene group. In one example, an isobornyl group may be used, but the present invention is not limited thereto.

[0082] The unit of the above chemical formula 2 may refer to a unit that is polymerized within the polymer component and included in the form of chemical formula 2, or a monomer unit that is pre-polymerized and can form the form of chemical formula 2 when polymerized.

[0083] The unit of Chemical Formula 2 above may be included in an amount of 40 to 90 parts by weight per 100 parts by weight of an alkyl acrylate unit having a straight-chain or branched-chain alkyl group. The alkyl acrylate unit having a straight-chain or branched-chain alkyl group refers to an alkyl acrylate unit having a straight-chain or branched-chain alkyl group in which the alkyl group is in an unsubstituted state.

[0084] Specifically, the unit of Formula 2 may be included in an amount of 45 parts by weight or more, 50 parts by weight or more, 55 parts by weight or more, 60 parts by weight or more, 65 parts by weight or more, 70 parts by weight or more, 75 parts by weight or more, 80 parts by weight or more, or 85 parts by weight or more, based on 100 parts by weight of an alkyl acrylate unit having a straight-chain or branched-chain alkyl group, or 85 parts by weight or less, 80 parts by weight or less, 75 parts by weight or less, 70 parts by weight or less, 65 parts by weight or less, 60 parts by weight or less, or 55 parts by weight or less.

[0085] When the unit of Chemical Formula 2 is included in the above range, the range of the glass transition temperature value, the storage modulus value at 25°C, and the creep strain value at 50°C of the curable composition as described above can be satisfied.

[0086] As a unit of the above chemical formula 2, the unit in which R of chemical formula 2 is hydrogen and the unit in which R of chemical formula 2 is an alkyl group may be simultaneously included. In this case, the weight ratio (C / D) of the unit in which R is hydrogen (C) and the unit in which R is an alkyl group (D) may be 1 or less. The weight ratio may be 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, 0.4 or less, or 0.2 or less, or 0 or more, 0.05 or more, 0.1 or more, 0.2 or more, 0.3 or more, or 0.4 or more.

[0087] The above polymer component may additionally include a unit of the following chemical formula 3.

[0088] [Chemical Formula 3]

[0089]

[0090] In Chemical Formula 3, R is hydrogen or an alkyl group, L is an alkylene group or an alkylidene group, and m is a number in the range of 1 to 10.

[0091] In Chemical Formula 3, the alkylene group or alkylidene group may mean an alkylene group or alkylidene group having 1 to 10 carbon atoms, 1 to 8 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms.

[0092] The unit of the above chemical formula 3 may include, for example, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 6-hydroxyhexyl acrylate, 8-hydroxyoctyl acrylate, 2-hydroxypolyethylene glycol acrylate or 2-hydroxypolypropylene glycol acrylate, but is not limited thereto.

[0093] The unit of the above chemical formula 3 may refer to a unit that is polymerized within the polymer component and included in the form of chemical formula 3, or a monomer unit that is pre-polymerized and can form the form of chemical formula 3 when polymerized.

[0094] The unit of Chemical Formula 3 above may be included in an amount of 10 to 40 parts by weight per 100 parts by weight of an alkyl acrylate unit having a straight-chain or branched-chain alkyl group. The alkyl acrylate unit having a straight-chain or branched-chain alkyl group refers to an alkyl acrylate unit having a straight-chain or branched-chain alkyl group in which the alkyl group is in an unsubstituted state.

[0095] In another example, the unit of Formula 3 may be included in an amount of 12 parts by weight or more, 15 parts by weight or more, 18 parts by weight or more, 20 parts by weight or more, 22 parts by weight or more, or 24 parts by weight or more, or 35 parts by weight or less, 30 parts by weight or less, 25 parts by weight or less, 20 parts by weight or less, 15 parts by weight or less, or 12 parts by weight or less, relative to 100 parts by weight of an alkyl acrylate unit having a straight-chain or branched-chain alkyl group.

[0096] 0.5 to 50 parts by weight of methacrylate units may be included per 100 parts by weight of total acrylate units included in the polymer component above. The total acrylate units refer to all alkyl acrylate units having straight-chain or branched-chain alkyl groups, including both substituted and unsubstituted states of the alkyl group. The methacrylate units refer to all alkyl methacrylate units having straight-chain or branched-chain alkyl groups, including both substituted and unsubstituted states of the alkyl group.

[0097] In another example, the methacrylate unit may be included in an amount of 1 part by weight or more, 3 parts by weight or more, 5 parts by weight or more, 8 parts by weight or more, 11 parts by weight or more, 14 parts by weight or more, 17 parts by weight or more, 20 parts by weight or more, or 22 parts by weight or more, or 45 parts by weight or less, 40 parts by weight or less, 35 parts by weight or less, 30 parts by weight or less, 25 parts by weight or less, 20 parts by weight or less, 15 parts by weight or less, 10 parts by weight or less, 5 parts by weight or less, or 2 parts by weight or less, relative to 100 parts by weight of the total acrylate unit.

[0098] In the case where R in the above chemical formula 2 is hydrogen and R in the above chemical formula 3 is hydrogen, while satisfying the above content range, the unit of chemical formula 2 may be included in an amount of 40 to 90 parts by weight per 100 parts by weight of an alkyl acrylate unit having a straight-chain or branched-chain alkyl group, and the unit of chemical formula 3 may be included in an amount of 10 to 40 parts by weight per 100 parts by weight of an alkyl acrylate unit having a straight-chain or branched-chain alkyl group.

[0099] In addition, the polymer component may include alkyl methacrylate units having a straight-chain or branched-chain alkyl group as methacrylate units in an amount of 1 to 60 parts by weight per 100 parts by weight of alkyl acrylate units having a straight-chain or branched-chain alkyl group. The alkyl acrylate units having a straight-chain or branched-chain alkyl group refer to alkyl acrylate units having a straight-chain or branched-chain alkyl group in which the alkyl group is in an unsubstituted state.

[0100] In another example, alkyl methacrylate units having a straight-chain or branched-chain alkyl group may be included in an amount of 2 parts by weight or more, 5 parts by weight or more, 8 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, 25 parts by weight or more, 30 parts by weight or more, 35 parts by weight or more, or 40 parts by weight or more, based on 100 parts by weight of alkyl acrylate units having a straight-chain or branched-chain alkyl group, or 55 parts by weight or less, 50 parts by weight or less, 45 parts by weight or less, 40 parts by weight or less, 35 parts by weight or less, 30 parts by weight or less, 25 parts by weight or less, 20 parts by weight or less, 15 parts by weight or less, 10 parts by weight or less, 5 parts by weight or less, or 3 parts by weight or less.

[0101] The above-mentioned alkyl methacrylate units having a straight-chain or branched-chain alkyl group may be exemplified, but are not limited to, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, sec-butyl methacrylate, pentyl methacrylate, 2-ethylhexyl methacrylate, 2-ethylbutyl methacrylate, isononyl methacrylate, n-octyl methacrylate, or isooctyl methacrylate.

[0102] The above polymer component may include 1 to 20 parts by weight of the unit of Formula 1 per 100 parts by weight of the alkyl acrylate unit having a straight-chain or branched-chain alkyl group. The alkyl acrylate unit having a straight-chain or branched-chain alkyl group refers to an alkyl acrylate unit having a straight-chain or branched-chain alkyl group in which the alkyl group is unsubstituted.

[0103] In another example, the unit of Formula 1 may be included in an amount of 2 parts by weight or more, 3 parts by weight or more, 4 parts by weight or more, 5 parts by weight or more, 6 parts by weight or more, 7 parts by weight or more, 8 parts by weight or more, or 9 parts by weight or more, based on 100 parts by weight of an alkyl acrylate unit having a straight-chain or branched-chain alkyl group, or 18 parts by weight or less, 16 parts by weight or less, 14 parts by weight or less, 12 parts by weight or less, 10 parts by weight or less, 8 parts by weight or less, or 7 parts by weight or less.

[0104] The unit of the above chemical formula 1 may simultaneously include a unit in which both R1 and R2 of chemical formula 1 are hydrogen, and a unit in which at least one of R1 and R2 of chemical formula 1 is not hydrogen. Examples of units in which both R1 and R2 of chemical formula 1 are hydrogen include acrylamide or methacrylamide. Examples of units in which at least one of R1 and R2 of chemical formula 1 is not hydrogen include N-methyl acrylamide, N-isopropyl acrylamide, N-butyl acrylamide and N-hexyl acrylamide, N,N-dimethyl acrylamide or N,N-diethyl acrylamide.

[0105] In the case where the unit of Chemical Formula 1 includes a unit in which both R1 and R2 are hydrogen and a unit in which at least one of R1 and R2 is not hydrogen, the ratio (E / F) of the weight of the unit in which both R1 and R2 are hydrogen (E) and the weight of the unit in which at least one of R1 and R2 is not hydrogen (F) may be 2 or less, 1.8 or less, 1.6 or less, 1.4 or less, 1.2 or less, 1 or less, 0.8 or less, 0.6 or less, 0.4 or less, or 0.3 or less, or 0.05 or more, 0.1 or more, 0.15 or more, or 0.2 or more.

[0106] By satisfying the above range of weight ratio (E / F), the curable composition of the present application can satisfy the storage modulus value range at 50°C and 85°C and the creep strain value range at 50°C as described above.

[0107] The above polymer component may contain a unit in which both R1 and R2 of Formula 1 are hydrogen in an amount of 3 parts by weight or less per 100 parts by weight of an alkyl acrylate unit having a straight-chain or branched-chain alkyl group. The above alkyl acrylate unit having a straight-chain or branched-chain alkyl group refers to an alkyl acrylate unit having a straight-chain or branched-chain alkyl group in which the alkyl group is in an unsubstituted state.

[0108] In another example, the unit in which R1 and R2 of Formula 1 are both hydrogen may be included in an amount of 2.8 parts by weight or less, 2.6 parts by weight or less, 2.4 parts by weight or less, 2.2 parts by weight or less, 2 parts by weight or less, 1.8 parts by weight or less, 1.6 parts by weight or less, 1.4 parts by weight or less, 1.2 parts by weight or less, 1 part by weight or less, 0.7 parts by weight or less, or 0.5 parts by weight or less, based on 100 parts by weight of the alkyl acrylate unit having a straight-chain or branched-chain alkyl group, or in an amount of 0.2 parts by weight or more, 0.5 parts by weight or more, 0.7 parts by weight or more, 0.9 parts by weight or more, 1.1 parts by weight or more, 1.3 parts by weight or more, 1.5 parts by weight or more, 1.7 parts by weight or more, or 1.9 parts by weight or more.

[0109] The above polymer component may have a ratio (A / B) of the unit weight (A) of Formula 3 and the unit weight (B) of Formula 1 of 2 or more. In other examples, the ratio (A / B) may be 1 or more, 1.2 or more, 1.4 or more, 1.6 or more, 1.8 or more, 2 or more, 2.1 or more, 2.2 or more, 2.3 or more, 2.4 or more, or 2.5 or more. The upper limit of the ratio (A / B) is not limited, but may be, for example, 6 or less, 5 or less, 4 or less, 3 or less, or 2 or less. By satisfying the above range, the curable composition of the present application can achieve haze characteristics as described above.

[0110] The above polymer component may additionally include a unit of the following chemical formula 4.

[0111] [Chemical Formula 4]

[0112]

[0113] In Chemical Formula 4, R1 is hydrogen or an alkyl group, and R3 is an aromatic ketone group or a (meth)acryloyl group. The aromatic ketone group or (meth)acryloyl group may exist in that state within the curable composition, or may exist in a state after undergoing the hydrogen removal reaction or radical reaction described below.

[0114] The unit of the above chemical formula 4 may refer to a unit that is polymerized within the polymer component and included in the form of chemical formula 4, or a monomer unit that is pre-polymerized and can form the form of chemical formula 4 when polymerized.

[0115] In Chemical Formula 4, the aromatic ketone group refers to an aromatic ketone group or a substituent containing such an aromatic ketone group that induces hydrogen abstraction from the polymer chain when exposed to ultraviolet light.

[0116] When an adhesive prepared with the curable composition of the present application is exposed to ultraviolet light, the aromatic ketone group may remove hydrogen atoms from other polymer chains or from other parts of the polymer chains. This removal causes the formation of radicals, which may form cross-links between polymer chains or within the same polymer chain. This category of aromatic ketone groups includes, for example, aromatic ketone groups such as derivatives of benzophenone, acetophenone, or anthroquinone.

[0117] Units capable of deriving the unit of Chemical Formula 4 having such aromatic ketone groups include, but are not limited to, 4-benzoylphenyl (meth)acrylate, 4-(meth)acryloyloxyethoxybenzophenone, 4-(meth)acryloyloxy-4'-methoxybenzophenone, 4-(meth)acryloyloxyethoxy4'-methoxybenzophenone, 4-(meth)acryloyloxy-4'-bromobenzophenone and / or 4-acryloyloxyethoxy-4'-bromobenzophenone.

[0118] Meanwhile, in the unit of Chemical Formula 4 above, the (meth)acryloyl group refers to a (meth)acryloyl group or a substituent containing it that induces free radical polymerization when exposed to ultraviolet light in the presence of a suitable radical initiator. Such (meth)acryloyl groups can perform a function similar to the aromatic ketone group upon irradiation with ultraviolet light.

[0119] The unit of Formula 4, in which R3 is a (meth)acryloyl group, can be formed, for example, by preparing a precursor copolymer and then further reacting it with an unsaturated reagent compound to introduce the (meth)acryloyl group. Typically, the introduction of the (meth)acryloyl group involves (1) a reaction between a nucleophilic group on the precursor copolymer and an electrophilic group on the unsaturated reagent compound (i.e., the unsaturated reagent compound contains both the electrophilic group and the (meth)acryloyl group), or (2) a reaction between an electrophilic group on the precursor copolymer and a nucleophilic group on the unsaturated reagent compound (i.e., the unsaturated reagent compound contains both the nucleophilic group and the (meth)acryloyl group). These reactions between the nucleophilic group and the electrophilic group are typically ring-opening reactions, addition reactions, or condensation reactions.

[0120] In these cases, the precursor copolymer has a hydroxyl, carboxylic acid (-COOH), or anhydride (-O-(CO)-O-) group. If the precursor copolymer has a hydroxyl group, the unsaturated reagent compound often has a carboxylic acid (-COOH), isocyanato (-NCO), epoxy (i.e., oxiranyl), or anhydride group in addition to the (meth)acryloyl group. If the precursor copolymer has a carboxylic acid group, the unsaturated reagent compound often has a hydroxyl, amino, epoxy, isocyanato, aziridinyl, azetidinyl, or oxazolinyl group in addition to the (meth)acryloyl group. If the precursor (meth)acrylate copolymer has an anhydride group, the unsaturated reagent compound often has a hydroxyl or amine group in addition to the (meth)acryloyl group.

[0121] In one example, the precursor copolymer has a carboxylic acid group, and the unsaturated reagent compound may have an epoxy group. Exemplary unsaturated reagent compounds include, for example, glycidyl (meth)acrylate and 4-hydroxybutyl acrylate glycidyl ether. In another example, the precursor copolymer has an anhydride group, which reacts with an unsaturated reagent compound that is a hydroxy-substituted alkyl (meth)acrylate, for example, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, etc. In yet another example, the precursor copolymer has a hydroxy group, and the unsaturated reagent compound has an isocyanato group and a (meth)acryloyl group. Such unsaturated reagent compounds include, but are not limited to, isocyanatoalkyl (meth)acrylates, e.g., isocyanatoethyl (meth)acrylate.

[0122] The above (meth)acryloyl group is, in one example, the chemical formula CH2=CHR 1 It may be represented as -(CO)-QL- (where L is a linker and Q is oxy(-O-) or -NH-). In the above, L comprises an alkylene, an arylene, or a combination thereof, and optionally further comprises -O-, -O-(CO)-, -NH-(CO)-, -NH-, or a combination thereof, depending on the precursor copolymer and a specific unsaturated reagent compound reacted to form a (meth)acryloyl group. In some specific examples, the (meth)acryloyl group is the (meth)acryloyl group of the chemical formula -(CO)-OR of the precursor copolymer. 5 Hydroxy-containing groups represented by -OH and the chemical formula H2C=CHR 1 -(CO)-OR 6 H2C=CHR formed by the reaction with an unsaturated reagent compound, which is an isocyanatoalkyl (meth)acrylate represented by -NCO 1 -(CO)-OR 6 -NH-(CO)-OR 5 It is -O-(CO)-. In the above, R 5 and R 6Each is independently an alkylene group, for example, an alkylene having 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. In addition, R in the above 1 It is methyl or hydrogen.

[0123] Meanwhile, in the unit of Chemical Formula 4, R1 may be hydrogen or an alkyl group having 1 to 4 carbon atoms, and specifically may be hydrogen, methyl, or ethyl group.

[0124] The unit of Formula 4 above may be included in an amount of 0.001 to 5 parts by weight per 100 parts by weight of a polymer component comprising the alkyl acrylate unit having a straight-chain or branched-chain alkyl group, the methacrylate unit, and the unit of Formula 1 above. The alkyl acrylate unit having a straight-chain or branched-chain alkyl group refers to the entire alkyl acrylate unit having a straight-chain or branched-chain alkyl group including both substituted and unsubstituted states of the alkyl group, and the methacrylate unit refers to the entire alkyl methacrylate unit having a straight-chain or branched-chain alkyl group including both substituted and unsubstituted states of the alkyl group.

[0125] Specifically, the ratio of the unit of Formula 4 may be approximately 0.005 parts by weight or more, 0.01 parts by weight or more, 0.03 parts by weight or more, 0.05 parts by weight or more, 0.07 parts by weight or more, 0.1 parts by weight or more, 0.3 parts by weight or more, 0.5 parts by weight or more, 0.7 parts by weight or more, or 0.9 parts by weight or more, based on 100 parts by weight of a polymer component comprising the alkyl acrylate unit having a straight-chain or branched-chain alkyl group, the methacrylate unit, and the unit of Formula 1; or 4.5 parts by weight or less, 4 parts by weight or less, 3.5 parts by weight or less, 3 parts by weight or less, 2.5 parts by weight or less, 2 parts by weight or less, 1.5 parts by weight or less, 1 part by weight or less, 0.5 parts by weight or less, 0.3 parts by weight or less, or 0.2 parts by weight or less.

[0126] The above polymer component may additionally include a compound unit represented by the following chemical formula 5.

[0127] [Chemical Formula 5]

[0128]

[0129] In Chemical Formula 5, R1 is hydrogen or an alkyl group, and R2 and R3 are each independently hydrogen or an alkyl group.

[0130] The compound unit represented by Chemical Formula 5 above can act as a chain transfer agent (CTA) in a curable composition. Chain transfer agents are widely known in the field of polymerization for controlling molecular weight or other polymer properties. Examples of the compound unit represented by Chemical Formula 5 above include, but is not limited to, N,N-dimethylaminoethyl methacrylate (DMAEMA), N,N-diethylaminoethyl methacrylate (DEAEMA), tert-butylaminoethyl methacrylate (TBAEMA), etc.

[0131] The content of a sulfur atom or a sulfur-containing compound in the above curable composition may be 1000 ppm or less. Specifically, the content of the sulfur atom or a sulfur-containing compound may be 700 ppm or less, 500 ppm or less, 300 ppm or less, 100 ppm or less, 50 ppm or less, or 30 ppm or less, and most preferably 0 ppm.

[0132] Since the chain transfer agent used in the present invention contains almost no sulfur atoms or sulfur-containing compound components, there is an advantage that the adhesive prepared as a curable composition does not corrode.

[0133] In one example, the polymer component may include a partial polymer component formed by partially polymerizing an alkyl acrylate unit having a straight-chain or branched-chain alkyl group, a methacrylate unit, a unit of Formula 1, a unit of Formula 4, and a unit of Formula 5. The alkyl acrylate unit having a straight-chain or branched-chain alkyl group refers to the entire alkyl acrylate unit having a straight-chain or branched chain, including both a state in which the alkyl group is substituted or unsubstituted, and the methacrylate unit refers to an alkyl methacrylate unit having a straight-chain or branched-chain alkyl group in which the alkyl group is unsubstituted.

[0134] The weight-average molecular weight of the partial polymer component of the present application may be 300,000 g / mol or less. Specifically, the weight-average molecular weight of the partial polymer component of the present application may be 270,000 g / mol or less, 250,000 g / mol or less, 230,000 g / mol or less, 210,000 g / mol or less, 190,000 g / mol or less, 170,000 g / mol or less, 150,000 g / mol or less, 130,000 g / mol or less, 110,000 g / mol or less, 90,000 g / mol or less, 70,000 g / mol or less, or 50,000 g / mol or less. The lower limit of the weight-average molecular weight of the above-mentioned partial polymer component may be 20,000 g / mol or more, 50,000 g / mol or more, 80,000 g / mol or more, 100,000 g / mol or more, 110,000 g / mol or more, 120,000 g / mol or more, 130,000 g / mol or more, 140,000 g / mol or more, or 150,000 g / mol or more.

[0135] The curable composition may include a radical crosslinking agent together with the polymer component. Such a crosslinking agent forms a crosslinked structure through a radical reaction.Examples of such radical crosslinking agents include so-called polyfunctional acrylates, such as 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxyl puivalic acid neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified di(meth)acrylate, di(meth)acryloxyethyl isocyanurate, and allylated cyclohexyl Difunctional acrylates such as di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, dimethylol dicyclopentane di(meth)acrylate, ethylene oxide-modified hexahydrophthalic acid di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, neopentyl glycol-modified trimethylpropane di(meth)acrylate, adamantane di(meth)acrylate, or 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, etc.; Trifunctional acrylates such as trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, trifunctional urethane (meth)acrylate, or tris(meth)acryloxyethyl isocyanurate; tetrafunctional acrylates such as diglycerin tetra(meth)acrylate or pentaerythritol tetra(meth)acrylate; pentafunctional acrylates such as propionic acid-modified dipentaerythritol penta(meth)acrylate; and dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate or urethane (meth)acrylate (ex.Examples include hexafunctional acrylates such as isocyanate monomers and reactants of trimethylolpropane tri(meth)acrylate, but are not limited thereto.

[0136] In the above curable composition, a radical crosslinking agent may be present in an appropriate ratio depending on the purpose. For example, the radical crosslinking agent may be included in an amount of 0.1 parts by weight or less per 100 parts by weight of the polymer component. In another example, the radical crosslinking agent may be included in an amount of 0.07 parts by weight or less, 0.05 parts by weight or less, 0.03 parts by weight or less, 0.01 parts by weight or less, or 0.009 parts by weight or less per 100 parts by weight of the polymer component, or in an amount of 0 parts by weight or more, 0.001 parts by weight or more, 0.003 parts by weight or more, 0.005 parts by weight or more, or 0.007 parts by weight or more. When the radical crosslinking agent is included in the above range, the curable composition may satisfy the storage modulus value range at 50°C and 85°C and the creep change rate value range at 50°C as described above.

[0137] The curable composition of the present application may additionally include necessary components in addition to the above components. The curable composition may additionally include a radical initiator, for example, a photoradical initiator.

[0138] Radical initiators include, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaninoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morphorino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetophenone dimethylketal, p-dimethylaminobenzoic acid ester, oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone] or 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, etc. may be used, but are not limited thereto.

[0139] The above-mentioned photoradical initiator may be included in the curable composition in an appropriate proportion. For example, it may be included in a ratio of about 0.1 to 3 parts by weight relative to 100 parts by weight of the polymer component. In another example, the photoradical initiator may be included in an amount of 0.15 parts by weight or more, 0.2 parts by weight or more, 0.25 parts by weight or more, or 0.3 parts by weight or more relative to 100 parts by weight of the polymer component, and may be included in an amount of 2 parts by weight or less, 1.5 parts by weight or less, 1 part by weight or less, 0.8 parts by weight or less, 0.6 parts by weight or less, or 0.4 parts by weight or less. When the photoradical initiator is included within the above range, the optical properties of the curable composition and the cured product as described above can be satisfied.

[0140] The curable composition may also additionally include a silane coupling agent. The silane coupling agent can improve the adhesion and adhesive stability of the adhesive, thereby improving heat resistance and moisture resistance, and also improve adhesive reliability even when left for a long period under harsh conditions.

[0141] Silane coupling agents include, for example, gamma-glycidoxypropyl triethoxysilane, gamma-glycidoxypropyl trimethoxysilane, gamma-glycidoxypropyl methyldiethoxysilane, gamma-glycidoxypropyl triethoxysilane, 3-mercaptopropyl trimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, gamma-methacryloxypropyl trimethoxysilane, gamma-methacryloxypropyl triethoxysilane, gamma-aminopropyl trimethoxysilane, gamma-aminopropyl triethoxysilane, 3-isocyanatopropyl triethoxysilane, gamma-acetoacetatepropyl trimethoxysilane, gamma-acetoacetatepropyl triethoxysilane, beta-cyanoacetyl trimethoxysilane, beta-cyanoacetyl triethoxysilane, acetoxyacetyl Trimethoxysilane, etc., may be used, and one type or a mixture of two or more of the above may be used.

[0142] The above silane coupling agent may be included in the curable composition in an appropriate proportion. For example, it may be included in an amount of 0.5 parts by weight or less per 100 parts by weight of the polymer component. In other examples, the silane coupling agent may be included in an amount of 0.4 parts by weight or less, 0.35 parts by weight or less, 0.3 parts by weight or less, or 0.25 parts by weight or less per 100 parts by weight of the polymer component, or in an amount of 0 parts by weight or more, 0.1 parts by weight or more, or 0.15 parts by weight or more.

[0143] The curable composition of the present application can be manufactured into an adhesive layer by undergoing a secondary curing (post-curing) after primary curing as described above. The primary curing and secondary curing may be photocuring.

[0144] In one example, the primary curing may be photocuring performed by irradiating ultraviolet light using a black light ultraviolet lamp or the like. The primary curing may be performed using ultraviolet light having a wavelength in the range of about 340 to 400 nm, preferably ultraviolet light with a wavelength range including 365 nm, at about 0.1 J / cm² 2 Up to 3J / cm 2 With a light intensity of, preferably 1 J / cm² 2 It can be performed by irradiating with the amount of light.

[0145] In one example, the secondary curing may be photocuring performed by irradiating the adhesive layer formed by primary curing with ultraviolet light, such as a metal halide lamp or a mercury ultraviolet lamp. The secondary curing may be performed using ultraviolet light having a wavelength in the range of about 315 nm to 420 nm, preferably in a wavelength range including 340 nm, at about 2 J / cm² 2 Up to 10 J / cm 2 The light intensity, preferably 3J / cm² 2 This can be performed by irradiating with a light intensity. According to the present application, when a second curing is performed after the first curing of the curable composition, the crosslinking density is increased so that the glass transition temperature value and the storage modulus value at 25°C of the curable composition as described above can be satisfied. Accordingly, an adhesive layer can be provided that can be bent well in curved or deformable parts, has excellent recovery characteristics to its original state so that there are no defects after recovery, and has the advantages of being easy to work with and cut.

[0146] The present application also relates to an adhesive film or an optical laminate comprising a base film and an adhesive layer formed on one or both sides of the base film.

[0147] That is, the adhesive layer of the present application may be formed on one or both sides of a substrate film to form an adhesive film, or formed on one or both sides of the substrate film which is an optical film to form an optical laminate.

[0148] The type of substrate film that can be applied at this time is not particularly limited. As the substrate film, a substrate film that can typically be applied to the formation of an adhesive film may be used.

[0149] For example, as a substrate film, PET (poly(ethylene terephthalate)) film, PTFE (poly(tetrafluoroethylene)) film, PP (polypropylene) film, PE (polyethylene) film, polyimide film, polyamide film, COP (cyclic olefin polymer) film, polybutene film, polybutadiene film, vinyl chloride copolymer film, polyurethane film, ethylene-vinyl acetate film, ethylene-propylene copolymer film, ethylene-ethyl acrylate copolymer film, ethylene-methyl acrylate copolymer film and / or polyimide film may be used, but are not limited thereto.

[0150] The thickness of the aforementioned film is not particularly limited and may have an appropriate thickness within a range suitable for the purpose.

[0151] In addition, if an optical film is applied as the substrate film, there are no special restrictions on the type of optical film. In one example, the optical film may be a polarizing film, a polarizer, or a phase difference film. Even in such cases, the optical film may have a thickness within an appropriate range depending on the purpose.

[0152] The adhesive film or optical laminate may also additionally include a release film or a protective film to protect the adhesive layer until use, if necessary.

[0153] The present application also relates to a display device comprising an adhesive layer, an adhesive film, or an optical laminate that is the curable composition or a cured product of the curable composition. The display device may be a curved display device or a flexible display device.

[0154] There are no special restrictions on the application form of the adhesive layer, adhesive film, or optical laminate in the above-mentioned display device. For example, the adhesive layer may be used as a so-called OCA (optically clear adhesive) or OCR (optically clear resin) in the display device, and the application form of the adhesive layer, adhesive film, or optical laminate may be the same as the application form of conventional OCA or OCR.

[0155] In such cases, in one example, the curved or flexible display device may include a display panel and an adhesive layer comprising an adhesive layer, an adhesive film, or an optical laminate present on one or both sides of the display panel.

[0156] In the present application, a curved display device refers to a display device configured to maintain a state in which a display panel is bent into a curved shape. Additionally, in the present application, a flexible display device refers to a display device configured to allow a display panel to be folded or rolled through one or more folding axes or rolling axes.

[0157] There are no special limitations on other elements constituting the curved or flexible display device as described above, and components of known display devices may be employed without limitation. Effects of the invention

[0158] The present application can provide a curable composition capable of manufacturing an adhesive that can be bent well on curved or deformable parts, has excellent recovery characteristics to its original state so that there are no defects after recovery, and is easy to work with and cut.

[0159] The present application can also provide a curable composition capable of producing an adhesive that is laminated without lifting on curved surfaces during the lamination process and has excellent step-filling properties. Brief explanation of the drawing

[0160] Figure 1 is a diagram illustrating an exemplary graph used in the process of measuring creep strain and recovery rate. Specific details for implementing the invention

[0161] The present application will be specifically described through the following examples, but the scope of the present application is not limited by the following examples.

[0163] 1. Weight-average molecular weight (Mw) and Multivariance index ( PDI ) measurement

[0164] Number-average molecular weight (Mn) and weight-average molecular weight (Mw) were measured using Gel Permeation Chromatography (GPC). The sample to be analyzed was placed in a 20 ml vial and diluted in tetrahydrofuran (THF) solvent to a concentration of approximately 20 mg / mL. Subsequently, the standard sample for calibration and the sample to be analyzed were filtered through a syringe filter (pore size: 0.2 µm) before measurement. The analysis program used was Chemstation by Aglient Technologies, and the number-average molecular weight (Mn) and weight-average molecular weight (Mw) were determined by comparing the elution time of the sample with the calibration curve. Additionally, the Polydispersity Index (PDI) value is calculated by dividing the weight-average molecular weight (Mw) by the number-average molecular weight (Mn).

[0165] <GPC 측정 조건>

[0166] Measuring instrument: Aglient GPC (Aglient 1200 series, US)

[0167] Column: PL Mixed B 2 connected

[0168] Column temperature: 40℃

[0169] Eluent: THF (Tetrahydrofuran)

[0170] Flow rate: 1.0 µl / min

[0171] Concentration: 20 mg / mL (10 µL injection)

[0173] 2. Evaluation of Conversion Rate

[0174] The conversion rate was calculated as the ratio (%) of the total weight (W1) of the monomer component used in the reaction to produce the partial polymer component and the weight (W2) of the produced partial polymer component using the following formula D.

[0175] [Formula D]

[0176] Conversion Rate (%) = 100 × W2 / W1

[0178] Examples 1

[0179] Preparation of partial polymer components

[0180] 2-ethylhexyl acrylate (2-EHA) monomer, 2-ethylhexyl methacrylate (EHMA) monomer, 2-hydroxyethyl methacrylate (2-HEA) monomer, acrylamide (AAM) monomer, 4-benzoylphenyl methacrylate (BPMA) monomer, and chain transfer agent (CTA) components were introduced into a 2L reactor equipped with a cooling device for easy temperature control and nitrogen gas reflux.

[0181] Next, nitrogen gas was purged for 10 minutes to remove oxygen, and the temperature was raised to 80°C. Then, while in a stabilized state, a reaction initiator (V-70, Wako) was introduced in an amount of about 10 to 150 ppm at each initiation step, and the reaction initiation step was repeated 2 to 3 times, after which air was introduced to terminate the reaction. The weight-average molecular weight (Mw) of the partial polymer component obtained in this way was 152,000 g / mol, the polydispersity index (PDI) was 2.06, and the conversion rate was 49.77%.

[0182] Preparation of polymer components

[0183] Monomer components were added to the prepared dipolymer component such that 2-ethylhexyl acrylate (2-EHA) monomer, isobornyl acrylate (IBOA) monomer, 2-hydroxyethyl acrylate (2-HEA) monomer, 2-ethylhexyl methacrylate (EHMA), isobornyl methacrylate (IBOMA), acrylamide (AAM) monomer, and N,N-dimethylacryamide (DMAA) monomer were added in a weight ratio of 52.0:19.2:10.0:6.8:8.0:0.8:3.2 (2-EHA:IBOA:2-HEA:EHMA:IBOMA:AAM:DMAA). The weight ratio of the monomer components is a ratio calculated based on the total sum of the amounts of monomer components used for the preparation of the dipolymer and the amounts of the added monomer components.

[0184] In addition, a polymer component was prepared by adding 0.1 parts by weight of 4-benzoylphenyl methacrylate (BPMA) monomer based on 100 parts by weight, which is the total sum of the amount of monomer components used to prepare the partial polymer and the amount of added monomer components.

[0185] Preparation of a curable composition

[0186] A curable composition was prepared by combining 0.32 parts by weight of a photoinitiator, 0.008 parts by weight of a curing agent, and 0.2 parts by weight of an epoxy silane coupling agent per 100 parts by weight of a polymer component.

[0188] Examples 2 to 7 and Comparative example 1 to 6

[0189] Preparation of partial polymer components

[0190] To prepare a partial polymer component, a partial polymer component was prepared by the same method as in Example 1, except that the weight ratio of the monomer component was adjusted as shown in Table 1 below.

[0191] Preparation of polymer components

[0192] Monomer components were added to the above-mentioned partial polymer components such that the monomer weight ratio of the total polymer components is as shown in Table 2 below. The monomer weight ratio of the total polymer components is a ratio calculated based on the total sum of the amounts of monomer components used to manufacture the partial polymer and the amounts of added monomer components.

[0193] In addition, a polymer component was prepared by the same method as in Example 1 by adding 4-benzoylphenyl methacrylate (BPMA) monomer in an amount of weight listed in Table 2 below, based on a total of 100 parts by weight of the monomer components used for the preparation of the partial polymer and the amount of added monomer components.

[0194] Preparation of a curable composition

[0195] A curable composition was prepared by the same method as in Example 1, except that a photoinitiator, a curing agent, and an epoxy silane coupling agent were added to 100 parts by weight of the polymer component prepared above in the amounts shown in Table 3 below (parts by weight based on 100 parts by weight of the polymer component) to prepare the curable composition.

[0197] 2-EHA EHMA 2-HEA AAM IBOA BPMA CTA Mw(g / mol) PDI Conversion rate (%) Example 1 76 10 10 4 - 1 1(DMAEMA) 152,000 2.06 49.77 Example 2 76 10 10 4 - 1 1(DMAEMA) 152,000 2.06 49.77 Example 3 76 10 10 4 - 1 1(DMAEMA) 152,000 2.06 49.77 Example 4 76 10 10 4 - 0.5 0.7(DEAEMA) 153,000 2 41.16 Example 5 76 10 10 4 - 0.5 0.7(DMAEMA) 153,000 2 41.16 Example 6 79 10 6 5 - 1 1(DMAE1MA) 168,000 2.36 58.38 Example 7 45 - 15 - 40 0.5 1(n-DDM) 30,000 2.29 88.31 Comparative Example 1 76 10 10 4 - - 1(DMAEMA) 151,000 2.23 51.02 Comparative Example 2 76 10 10 4 - 1 0.7(DMAEMA) 320,000 2.41 40.64 Comparative Example 3 76 10 10 4 - 1 0.7(DEAEMA) 172,000 2.18 44.68 Comparative Example 4 81 10 6 3 - 1 0.2(tBAEMA) 180,000 3.5 32.26 Comparative Example 5 80 10 6 4 - 1 0.2(tBAEMA) 140,000 3.9 40.72 Comparative Example 6 70 10 20 - - 1 0.2 (TTMS) 160,000 3 60.02 2-EHA: 2-ethylhexyl acrylate EHMA: 2-ethylhexyl methacrylate 2-HEA: 2-hydroxyethyl acrylate AAM: Acrylamide IBOA: Isobornyl acrylate BPMA: 4-benzoylphenyl methacrylate DMAEMA: (2-dimethylaminoethyl) methacrylate DEAEMA: (2-diethylaminoethyl) methacrylate tBAEMA: 2-(tert-butylamino)ethyl methacrylate n-DDM: n-dodecyl mercaptan TTMS: Tris(trimethylsilyl) silane Mw: Weight-average molecular weight (unit: ten thousand) PDI: Polydispersity index

[0199] Solid content ratio after mixing (%) 2-EHA IBOA 2-HEA EHMA IBOMA AAM DMAA BPMA Example 1 20 52.0 19.2 10.0 6.8 8.0 0.8 3.2 0.100 Example 2 20 50.4 21.6 10.0 10.0 4.0 0.8 3.2 0.100 Example 3 20 48.0 24.0 10.0 14.0 0.0 0.8 3.2 0.100 Example 4 20 40.8 27.2 10.0 18.0 0.0 0.8 3.2 0.100 Example 5 20 45.6 22.4 10.0 10.0 8.0 0.8 3.2 0.100 Example 6 20 54.2 20.0 6.0 6.8 8.0 1.0 4.0 0.100 Example 7 45 45.0 40.0 11.2 1.0 0.0 0.0 2.8 1.000 Comparative Example 1 20 52.0 19.2 10.0 6.8 8.0 0.8 3.2 0.100 Comparative Example 2 20 52.0 19.2 10.0 6.8 8.0 0.8 3.2 0.100 Comparative Example 3 20 47.2 24.0 10.0 6.8 8.0 0.8 3.2 0.100 Comparative Example 4 20 56.2 22.4 6.0 4.4 8.0 0.6 2.4 0.100 Comparative Example 5 20 56.6 21.0 6.0 4.4 8.0 0.8 3.2 0.100 Comparative Example 6 20 46.0 21.6 20.0 4.4 8.0 0.0 0.0 0.100 IBOMA: Isobornyl methacrylate DMAA: N,N-dimethylacrylamide

[0201] Photoinitiator hardener Epoxy silane coupling agent Example 1 0.320 0.008 0.200 Example 2 0.320 0.008 0.200 Example 3 0.320 0.008 0.200 Example 4 0.320 0.008 0.200 Example 5 0.320 0.008 0.200 Example 6 0.320 0.008 0.200 Example 7 0.055 0.055 0.200 Comparative Example 1 0.320 0.008 0.200 Comparative Example 2 0.320 0.008 0.200 Comparative Example 3 0.320 0.008 0.200 Comparative Example 4 0.320 0.008 0.200 Comparative Example 5 0.320 0.008 0.200 Comparative Example 6 0.320 0.008 0.200 Photoinitiator: Irg 651, Ciba Specialty Chemicals Curating Agent: 1,6-Hexanediol Diacrylate (HDDA) Epoxysilane Coupling Agent: KBM 403, Shin-Etsu

[0203] Experimental Example1. Evaluation of Storage Modulus

[0204] Storage modulus was evaluated using TA's ARES G2 (Advanced Rheometric Expansion System G2).

[0205] The curable compositions of the examples and comparative examples were applied between release films, and a black light source with a wavelength range including 365 nm was applied for about 3 minutes and 30 seconds at about 1 J / m² 2 An adhesive layer with a thickness of 150㎛ was prepared by first irradiating with a light intensity.

[0206] The above adhesive layer, with a thickness of about 150 μm, was manufactured by stacking four layers to a thickness of about 600 μm, and the specimen was prepared by cutting it into a circular shape with a diameter of about 8 mm. The specimen was fixed to a parallel plate fixture with a diameter of about 8 mm, and the storage modulus of the specimen was evaluated at different measurement temperatures (25°C, 50°C, and 80°C).

[0207] For evaluation, measurements were taken under conditions of a frequency of 1 rad / sec, an axial force of 2 N, and a strain of 10%.

[0208] The measured storage modulus is summarized in Table 4 below.

[0209] 25℃ G'(Pa) 50℃ G'(Pa) 85℃ G'(Pa) Example 1 100,538 38,094 15,625 Example 2 72,935 34,599 14,906 Example 3 67,146 31,677 13,925 Example 4 66,460 32,928 9,949 Example 5 96,643 38,498 11,958 Example 6 124,772 38,375 14,615 Example 7 64,805 19,690 7,369 Comparative Example 1 81,042 34,408 11,816 Comparative Example 2 87,331 43,081 20,735 Comparative Example 3 111,792 42,098 16,686 Comparative Example 4 72,376 36,071 18,040 Comparative Example 5 97,687 57,089 40,104 Comparative Example 6 59,500 19,726 6,443

[0211] Experimental Example 2. Evaluation of Glass Transition Temperature

[0212] The glass transition temperature was evaluated using TA's ARES G2 (Advanced Rheometric Expansion System G2).

[0213] The curable compositions of the examples and comparative examples were applied between release films, and a black light source with a wavelength range including 365 nm was applied for about 3 minutes and 30 seconds at about 1 J / m² 2An adhesive layer with a thickness of 150㎛ was prepared by first irradiating with a light intensity.

[0214] The above adhesive layer, with a thickness of about 150 μm, was manufactured by stacking four layers to a thickness of about 600 μm, and the specimen was prepared by cutting it into a circle with a diameter of about 8 mm. The specimen was fixed to a parallel plate fixture with a diameter of about 8 mm, and the temperature dependence of the loss modulus (G") was measured using an ARES G2 device, and the temperature at which the obtained G" curve is maximized was set as the glass transition temperature (°C).

[0215] For evaluation, measurements were taken in a temperature range of -20℃ to 100℃ under conditions of a frequency of 1 rad / sec, an axial force of 2N, and a temperature increase of 5℃ / min.

[0216] The measured glass transition temperatures are summarized in Table 5 below.

[0217] Glass transition temperature (°C) Example 1 -2 Example 2 -2 Example 3 -2 Example 4 1 Example 5 2 Example 6 0 Example 7 0 Comparative Example 1 -2 Comparative Example 2 3 Comparative Example 3 5 Comparative Example 4 -3 Comparative Example 5 -3 Comparative Example 6 -1

[0219] Experimental Example 3. Evaluation of Creep Strain and Recovery Rate

[0220] Creep strain and recovery rate were evaluated in the following manner.

[0221] The curable compositions of the examples and comparative examples were applied between release films, and a black light source with a wavelength range including 365 nm was applied for about 3 minutes and 30 seconds at about 1 J / m² 2 An adhesive layer with a thickness of 150㎛ was prepared by first irradiating with a light intensity.

[0222] The above adhesive layer, with a thickness of about 150 μm, was manufactured by stacking four layers to a thickness of about 600 μm, and the specimen was prepared by cutting it into a circular shape with a diameter of about 8 mm. After aging the specimen at a temperature of 50°C, it was mounted on a parallel plate fixture with a diameter of about 8 mm, and a stress of about 6000 Pa in the shear direction was applied to the specimen for 175 seconds. The strain after removing the stress was evaluated by checking it as shown in Fig. 1.

[0223] In the graph of Figure 1, the x-axis is an axis showing the passage of time with the point at which stress begins to be applied being 0 seconds, and the y-axis is an axis representing the strain (strain, %) of the adhesive layer, and the strain is the result calculated according to the following formula A.

[0224] [Formula A]

[0225] Strain (Unit: %) = 100 × (La-Li) / Li

[0226] In Formula A, La is the thickness of the adhesive layer after deformation in the deformation direction (the direction in which stress was applied) measured after applying a stress of about 6000 Pa in the shear direction to the specimen for 175 seconds and removing the stress (unit: mm), and Li is the initial thickness of the adhesive layer before deformation (unit: mm).

[0227] The strain value of the adhesive layer confirmed by the above evaluation (e.g., 10 in Fig. 1) was designated as the creep strain (%) value.

[0228] In addition, the recovery rate was specified according to the following formula B.

[0229] [Formula B]

[0230] R% = 100 × (CS) / C

[0231] In formula B, R% is the recovery rate, C is the creep strain value, and S is the strain of the specimen at the point in time when stress of about 6000 Pa is applied to the specimen for 175 seconds, the stress is removed, and another 175 seconds have elapsed (e.g., 20 in FIG. 1).

[0232] The creep strain and recovery rate values ​​are summarized in Table 6 below.

[0233] Creep strain (%) Recovery rate (%) Example 1 81 76.4 Example 2 85 77.0 Example 3 98 76.9 Example 4 169 57.9 Example 5 121 61.1 Example 6 114 72.2 Example 7 141 74.2 Comparative Example 1 130 62.9 Comparative Example 2 54 83.4 Comparative Example 3 71 76.0 Comparative Example 4 75 84.2 Comparative Example 5 28 92.8 Comparative Example 6 321 62.41

[0235] Experimental Example 4. Light transmittance , Hayes , and Color index measurement

[0236] The curable compositions of the examples and comparative examples were applied between release films, and a black light source with a wavelength range including 365 nm was applied for about 3 minutes and 30 seconds at about 1 J / m² 2 An adhesive layer with a thickness of 150㎛ was prepared by first irradiating with a light intensity.

[0237] The adhesive layer was roll-laminated between 50mm × 50mm soda lime glass sheets, and an autoclave process was performed at 50°C and 5 bar to remove air bubbles. Afterward, haze and light transmittance were measured using a haze meter (Nippon Denshoku, NDH-5000). In addition, color difference was measured using a colorimeter (Conica Minolta, CM-5).

[0238] To the adhesive layer manufactured above, a metal halide light source with a wavelength range including 340 nm at approximately 3 J / m 2After a second irradiation with a light intensity, the adhesive layer was roll-laminated between 50mm × 50mm soda lime glass sheets, and an autoclave process was performed at 50℃ and 5 bar to remove bubbles. By the method described above, haze, light transmittance, and color difference were measured again.

[0239] The haze (H), light transmittance (T), and color difference (b*) before and after the second UV irradiation are summarized in Table 7 below.

[0240] Before the second UV irradiation After the second UV irradiation T(%) H(%) b* T(%) H(%) b* Example 1 91.8 0.2 0.4 91.8 0.2 0.7 Example 2 91.9 0.2 0.4 91.8 0.2 0.7 Example 3 91.9 0.2 0.4 91.8 0.2 0.7 Example 4 92.0 0.2 0.7 92.8 0.2 0.7 Example 5 91.6 0.2 0.9 92.0 0.4 1.0 Example 6 92.1 1.9 0.9 92.0 1.8 1.1 Example 7 92.2 0.2 0.2 92.1 0.2 0.7 Comparative Example 1 91.4 0.7 0.9 91.3 0.7 1.1 Comparative Example 2 91.6 0.2 0.4 91.4 0.2 0.7 Comparative Example 3 91.9 0.2 0.3 91.9 0.2 0.8 Comparative Example 4 91.5 0.2 0.4 91.4 0.2 0.8 Comparative Example 5 91.2 3.2 1.8 91.2 3.0 2.1 Comparative Example 6 91.5 6.7 2.9 91.5 6.4 3.0

[0242] Experimental Example 5. Measurement of gel content

[0243] The curable compositions of the examples and comparative examples were applied between release films, and a black light source with a wavelength range including 365 nm was applied for about 3 minutes and 30 seconds at about 1 J / m² 2 An adhesive layer with a thickness of 150㎛ was prepared by first irradiating with a light intensity.

[0244] The release film of the manufactured adhesive layer was removed, and the mixture was placed in a polyethylene bottle to measure its weight (a). Subsequently, ethyl acetate was added to the bottle to ensure the adhesive was sufficiently submerged, and the mixture was left at room temperature for 24 hours.

[0245] Next, the adhesive and ethyl acetate inside the polyethylene bottle were poured into a 200-mesh wire mesh (weight: b) cut to a size of 14 cm × 14 cm and filtered. Afterward, the wire mesh filtered of the adhesive was dried in a 150 ℃ oven for 1 hour, and its weight (c) was measured. The gel content (%) before the second UV irradiation was measured by substituting each of the measured weights a, b, and c into the following formula C.

[0246] [Equation C]

[0247] Gel content (%) = ((cb) / a) × 100

[0248] Subsequently, on the adhesive layer prepared by primary UV irradiation, a metal halide light source with a wavelength range including 340 nm at approximately 3 J / m² 2 After irradiating a second time with the amount of light, the gel content (%) after the second UV irradiation was measured in the same manner as described above.

[0249] The gel content (%) before and after the second UV irradiation is summarized in Table 8 below.

[0250] Gel content (%) Before the second UV irradiation After the second UV irradiation Example 1 52 72 Example 2 54 72 Example 3 54 74 Example 4 41 59 Example 5 42 58 Example 6 52 71 Example 7 52 67 Comparative Example 1 53 55 Comparative Example 2 71 84 Comparative Example 3 59 77 Comparative Example 4 69 86 Comparative Example 5 81 90 Comparative Example 6 66 74

Claims

Claim 1 A curable composition having a glass transition temperature of -10°C or higher, a storage modulus of 60,000 Pa or higher at 25°C, a creep strain of 80% or higher at 50°C, and a change rate ΔG of gel content according to Formula 1 of 10% or higher, wherein the curable composition comprises a polymer component comprising an alkyl acrylate unit having a straight-chain or branched-chain alkyl group, a methacrylate unit, a unit of Formula 1 below, and a unit of Formula 4 below, wherein the ratio of the unit of Formula 4 is 0.01 to 0.3 parts by weight per 100 parts by weight of the polymer component, and the curable composition is a primary cured composition: [Formula 1] ΔG = 100 × (Ga-Gi) / Gi, where Ga is 3 J / cm² of ultraviolet light with a wavelength of 340 nm. 2 It is the gel content after irradiating the curable composition with a light intensity, and Gi is 3 J / cm² of ultraviolet light with a wavelength of 340 nm. 2 The gel content before irradiating the curable composition with the amount of light, [Chemical Formula 1] In Formula 1, R is hydrogen or a methyl group, and R1 and R2 are each independently hydrogen, an alkyl group, an alkoxy group, an aryl group, or an aralkyl group; the curable composition comprises, as units of Formula 1, a unit in which both R1 and R2 are hydrogen and a unit in which at least one of R1 and R2 is not hydrogen, and the ratio (E / F) of the weight of the unit in which both R1 and R2 are hydrogen (E) and the weight of the unit in which at least one of R1 and R2 is not hydrogen (F) is 0.1 or more and 0.6 or less, [Formula 4] In Chemical Formula 4, R1 is hydrogen or an alkyl group, and R3 is an aromatic ketone group or a (meth)acryloyl group. Claim 2 In claim 1, a curable composition having a change rate ΔM1 of the storage modulus according to the following Equation 2 of 45% or more: [Equation 2] ΔM1 = 100 × (M25-M50) / M25 In Equation 2, M25 is the storage modulus of the curable composition at 25°C, and M50 is the storage modulus of the curable composition at 50°C. Claim 3 In claim 1, a curable composition having a change rate ΔM2 of the storage modulus according to the following Equation 3 of 45% or more: [Equation 3] ΔM2 = 100 × (M50-M85) / M50 In Equation 3, M50 is the storage modulus of the curable composition at 50°C, and M85 is the storage modulus of the curable composition at 85°C. Claim 4 A curable composition according to claim 1, wherein the recovery rate at 50°C is within the range of 40 to 90%. Claim 5 A curable composition according to claim 1, wherein the gel content Ga is within the range of 30% to 65%. Claim 6 delete Claim 7 A curable composition according to claim 1, comprising 30 to 70 weight% of alkyl acrylate units having a straight-chain or branched-chain alkyl group. Claim 8 The curable composition of claim 1, wherein the polymer component further comprises 40 to 90 parts by weight of a unit of the following formula 2 per 100 parts by weight of an alkyl acrylate unit having a straight-chain or branched-chain alkyl group: [Formula 2] In Chemical Formula 2, R is hydrogen or an alkyl group, and P is a monovalent substituent with a non-aromatic ring structure having 3 to 20 carbon atoms. Claim 9 A curable composition according to claim 8, comprising simultaneously a unit of Chemical Formula 2 in which R is hydrogen and a unit of Chemical Formula 2 in which R is an alkyl group. Claim 10 The curable composition of claim 1, wherein the polymer component further comprises 10 to 40 parts by weight of a unit of the following formula 3 per 100 parts by weight of an alkyl acrylate unit having a straight-chain or branched-chain alkyl group: [Formula 3] In Chemical Formula 3, R is hydrogen or an alkyl group, L is an alkylene group or an alkylidene group, and m is a number in the range of 1 to 10. Claim 11 A curable composition according to claim 1, comprising 0.5 to 50 parts by weight of methacrylate units per 100 parts by weight of total acrylate units included in the polymer component. Claim 12 A curable composition according to claim 1, wherein the polymer component comprises, as a methacrylate unit, alkyl methacrylate units having a straight-chain or branched-chain alkyl group in an amount of 1 to 60 parts by weight per 100 parts by weight of alkyl acrylate units having a straight-chain or branched-chain alkyl group. Claim 13 A curable composition according to claim 1, wherein the polymer component comprises 1 to 20 parts by weight of a unit of Formula 1 per 100 parts by weight of an alkyl acrylate unit having a straight-chain or branched-chain alkyl group. Claim 14 delete Claim 15 A curable composition according to claim 1, wherein the polymer component comprises a unit in which both R1 and R2 of Formula 1 are hydrogen, in an amount of 3 parts by weight or less per 100 parts by weight of an alkyl acrylate unit having a straight-chain or branched-chain alkyl group. Claim 16 A curable composition according to claim 1, wherein the polymer component further comprises a unit of the following chemical formula 3, and the ratio (A / B) of the weight of the unit of chemical formula 3 (A) to the weight of the unit of chemical formula 1 (B) is 1 or greater: [Chemical Formula 3] In Chemical Formula 3, R is hydrogen or an alkyl group, L is an alkylene group or an alkylidene group, and m is a number in the range of 1 to 10. Claim 17 delete Claim 18 The curable composition of claim 1, wherein the polymer component further comprises a compound unit represented by the following chemical formula 5: [Chemical Formula 5] In Chemical Formula 5, R1 is hydrogen or an alkyl group, and R2 and R3 are each independently hydrogen or an alkyl group. Claim 19 A curable composition according to claim 1, wherein the content of a sulfur atom or a sulfur-containing compound is 1,000 ppm or less. Claim 20 A display device comprising a secondary cured product of the curable composition of claim 1, and having a curved or flexible shape.

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