Pressure-sensitive adhesive composition, optical film including the same, organic electronic device and display device including the same

Abstract

The present application relates to a pressure-sensitive adhesive composition comprising a first (meth)acrylate resin and a second (meth)acrylate resin, wherein the melting temperature (Tm) of the second (meth)acrylate resin is higher by 20°C or more than the glass transition temperature (Tg) of the first (meth)acrylate resin, an optical film comprising the pressure-sensitive adhesive composition, and an organic electronic device and a display device comprising the pressure-sensitive adhesive composition.

Description

[Technical Field]

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2018-0132596, filed with the Korean Intellectual Property Office on October 31, 2018, the entire contents of which are incorporated herein by reference. The present application relates to a pressure-sensitive adhesive composition, an optical film including the same, and an organic electronic device and a display device including the same. [Background technology]

[0002] Optically clear adhesives (OCA) are widely used in electronic displays, such as organic light-emitting diodes (OLEDs) and liquid crystal displays (LCDs), to bond various components and layers of the electronic displays together.

[0003] Recently, in addition to flat displays, flexible displays that can be folded and unfolded have been actively researched. However, the plastic substrates used as the substrate material for flexible displays have a problem in that they have extremely poor barrier properties against gases such as moisture and oxygen.

[0004] To solve this problem, conventionally, a process surface protection film has been used to protect the thin film encapsulation (TFE) layer during the manufacturing process of flexible optical devices, by forming a barrier film with various materials and structures on the substrate.

[0005] In order to bond other components to a flexible display, the current method is to first attach the surface protection film for processing to the thin film encapsulation layer during processing for a while, then remove it, and then use an optically clear adhesive (OCA) to bond the electronic display to the other components. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Korean Patent Publication No. 10-2016-0039062 Summary of the Invention [Problem to be solved by the invention]

[0007] The present application aims to provide an optical film that protects the surface of an organic light-emitting element during the manufacturing process of an organic electronic element, has low adhesive strength during the process so that processes such as half-cutting are possible, and has high adhesive strength after the process is completed so that it is easy to attach the element to a touch screen. [Means for solving the problem]

[0008] One embodiment of the present application provides a pressure-sensitive adhesive composition comprising a first (meth)acrylate resin and a second (meth)acrylate resin, wherein the melting temperature (Tm) of the second (meth)acrylate resin is at least 20°C higher than the glass transition temperature (Tg) of the first (meth)acrylate resin.

[0009] Another embodiment of the present application provides an optical film comprising a substrate layer and a pressure-sensitive adhesive layer provided on one surface of the substrate layer, wherein the pressure-sensitive adhesive layer comprises the pressure-sensitive adhesive composition described above or a cured product thereof.

[0010] One embodiment of the present application provides an organic electronic device including an organic light-emitting element and a pressure-sensitive adhesive layer in contact with the organic light-emitting element, wherein the pressure-sensitive adhesive layer includes the pressure-sensitive adhesive composition described above; or a cured product thereof.

[0011] Another embodiment of the present application provides a display device, which is an organic electronic device including an organic light-emitting device, a touch screen, and an adhesive layer bonding the organic light-emitting device and the touch screen, wherein the adhesive layer includes the adhesive composition described above; or a cured product thereof. [Effects of the Invention]

[0012] By using a pressure-sensitive adhesive composition according to some embodiments of the present application, it is possible to realize a pressure-sensitive adhesive layer having a low adhesive strength of 100 gf / in or less before curing and a high adhesive strength of 800 gf / in or more after curing. An optical film including a pressure-sensitive adhesive layer according to some embodiments of the present application can protect the surface of an organic light-emitting element during the manufacturing process of the organic electronic element.

[0013] The adhesive layer according to some embodiments of the present application allows the organic light emitting device and the touch screen to be bonded together without the need for a separate OCA film, improving processability. DETAILED DESCRIPTION OF THE INVENTION

[0014] This specification will be explained in more detail below. In this specification, when a part "comprises" a certain component, this means that it can further include other components, rather than excluding other components, unless otherwise specified. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0015] In this specification, the term "polymer" is a general term for a compound in the form of polymerization of two or more monomers, and components usually called oligomers are also included in the monomers. In this specification, unless otherwise specified, "parts by weight" means "weight ratio".

[0016] One embodiment of the present application provides a pressure-sensitive adhesive composition comprising a first (meth)acrylate resin and a second (meth)acrylate resin, wherein the melting temperature (Tm) of the second (meth)acrylate resin is at least 20°C higher than the glass transition temperature (Tg) of the first (meth)acrylate resin.

[0017] When the melting temperature (Tm) of the second (meth)acrylate resin contained in the pressure-sensitive adhesive composition is at least 20°C higher than the glass transition temperature (Tg) of the first (meth)acrylate resin, a pressure-sensitive adhesive layer can be realized that has low adhesive strength before curing but high adhesive strength after curing.

[0018] In one embodiment, the melting temperature (Tm) of the second (meth)acrylate resin is 20° C. or more; 30° C. or more; 40° C. or more; or 50° C. or more higher than the glass transition temperature (Tg) of the first (meth)acrylate resin.

[0019] In one embodiment, the difference between the melting temperature (Tm) of the second (meth)acrylate resin and the glass transition temperature (Tg) of the first (meth)acrylate resin is not limited, but in one embodiment, may be 200°C or less; 180°C or less; or 150°C or less.

[0020] In one embodiment, the adhesive strength (A) of the pressure-sensitive adhesive composition before curing is 100 gf / in or less. In one embodiment, the adhesive strength (A) of the pressure-sensitive adhesive composition before curing is 2 gf / in or more, 5 gf / in or more, or 10 gf / in or more. If the adhesive strength (A) of the pressure-sensitive adhesive composition before curing is less than 2 gf / in, the adhesive strength between the surface of the adherend and the pressure-sensitive adhesive layer is low, and the optical film is likely to peel off from the surface of the adherend during processing.

[0021] The adhesive strength (A) of the pressure-sensitive adhesive composition before curing is the peel strength when the pressure-sensitive adhesive composition is coated on a polyethylene terephthalate (PET) film and dried at 110°C for 2 minutes to form a pressure-sensitive adhesive layer with a thickness of 25 μm, and the pressure-sensitive adhesive layer is peeled from a stainless steel plate (JIS SUS304) at a peel speed of 0.3 m / min and a peel angle of 180°.

[0022] In one embodiment, in measuring the adhesive strength (A), the peel strength when peeling the adhesive layer from the stainless steel plate is a value measured under conditions of 25°C and 50% relative humidity.

[0023] In one embodiment, the adhesive strength (B) of the adhesive composition after curing may be 800 gf / in or more, 1,000 gf / in or more, 1,500 gf / in or more, 2,000 gf / in or more, or 2,500 gf / in or more. Only when the adhesive strength (B) of the adhesive composition after curing is at least 800 gf / in or more can it easily adhere the element to the panel.

[0024] In one embodiment, in measuring the adhesive strength (B), the peel strength when peeling the adhesive layer from the stainless steel plate is a value measured under conditions of 25°C and 50% relative humidity.

[0025] In one embodiment, the adhesive strength (B) of the pressure-sensitive adhesive composition after curing is 4,000 gf / in or less; or 3,500 gf / in or less.

[0026] The adhesive strength (B) of the pressure-sensitive adhesive composition after curing is measured by coating the pressure-sensitive adhesive composition on a polyethylene terephthalate (PET) film, drying it at 110°C for 2 minutes to form a pressure-sensitive adhesive layer with a thickness of 25 μm, curing the pressure-sensitive adhesive layer for 20 minutes under conditions of 50°C and 0.5 MPa, and storing it for 30 minutes under conditions of a temperature of 25°C and a relative humidity of 50%, and then peeling the pressure-sensitive adhesive layer from a stainless steel plate (JIS SUS304) at a peel speed of 0.3 m / min at a peel angle of 180°.

[0027] In one embodiment, by increasing the difference between the melting temperature (Tm) of the second (meth)acrylate resin and the glass transition temperature (Tg) of the first (meth)acrylate resin, the difference between the adhesive strength (A) of the pressure-sensitive adhesive composition before curing and the adhesive strength (B) of the pressure-sensitive adhesive composition after curing can be increased.

[0028] In one embodiment, the melting temperature (Tm) of the second (meth)acrylate resin is at least 50° C. higher than the glass transition temperature (Tg) of the first (meth)acrylate resin.

[0029] In one embodiment, when the melting temperature (Tm) of the second (meth)acrylate resin is higher by 50°C or more than the glass transition temperature (Tg) of the first (meth)acrylate resin, the adhesive strength (B) of the pressure-sensitive adhesive composition after curing may be 2,500 gf / in or more.

[0030] In one embodiment, the melting temperature (Tm) of the second (meth)acrylate resin is at least 20° C. higher than the melting temperature (Tm) of the first (meth)acrylate resin.

[0031] In one embodiment, the glass transition temperature (Tg) of the second (meth)acrylate resin is at least 20° C. higher than the glass transition temperature (Tg) of the first (meth)acrylate resin.

[0032] In one embodiment, the glass transition temperature (Tg) of the second (meth)acrylate resin is at least 20° C. higher than the melting temperature (Tm) of the first (meth)acrylate resin.

[0033] In this application, melting temperature (Tm) refers to the temperature at which a substance undergoes a phase transition from a solid state to a liquid state. When a solid polymer is heated, a significant change in the three-dimensional structure occurs at a specific temperature, and a change corresponding to a phase transition can be observed. This temperature can be defined as the melting temperature.

[0034] In this application, the glass transition temperature (Tg) is the temperature at which micro-Brownian motion, in which segments (certain parts of molecular chains) move short distances in the amorphous part of an amorphous or crystalline polymer, begins to become visible.

[0035] The melting temperature and glass transition temperature can be measured by differential scanning calorimetry (DSC). Specifically, a 10 mg sample is sealed in a special pan and heated in a constant temperature environment, and the endothermic and exothermic amounts of the material are measured according to the temperature.

[0036] The polymer components contained in the pressure-sensitive adhesive composition can be confirmed by GC (Gas Chromatography) analysis, and the composition can be confirmed by NMR (Nuclear Magnetic Resonance) analysis.

[0037] The weight average molecular weight of the second (meth)acrylate resin is lower than the weight average molecular weight of the first (meth)acrylate resin.

[0038] If the weight average molecular weight of the second (meth)acrylate resin is lower than the weight average molecular weight of the first (meth)acrylate resin, the second (meth)acrylate resin rises to the surface of the adhesive layer during the process of coating the adhesive composition on a substrate and drying, and the adhesive strength of the adhesive layer before curing can be achieved to be 100 gf / in or less.

[0039] The adhesive strength of the first (meth)acrylate resin after curing is greater than the adhesive strength of the second (meth)acrylate resin before curing.

[0040] The adhesive strength of the first (meth)acrylate resin after curing is measured by coating a polyethylene terephthalate (PET) film with an adhesive composition consisting of 100 parts by weight of the first (meth)acrylate resin and 65 parts by weight of toluene, drying the coating at 110°C for 2 minutes to form an adhesive layer having a thickness of 25 μm, curing the adhesive layer for 20 minutes under conditions of 50°C and 0.5 MPa, and storing the adhesive layer for 30 minutes under conditions of 25°C and 50% relative humidity. The adhesive strength is measured by peeling the adhesive layer from a stainless steel plate (JIS SUS304) at a peel speed of 0.3 m / min at a peel angle of 180°.

[0041] The adhesive strength of the second (meth)acrylate resin before curing is the peel strength when an adhesive composition consisting of 100 parts by weight of the second (meth)acrylate resin and 65 parts by weight of toluene is coated on a polyethylene terephthalate (PET) film and dried at 110°C for 2 minutes to form an adhesive layer with a thickness of 25 μm, and the adhesive layer is peeled from a stainless steel plate (JIS SUS304) at a peel speed of 0.3 m / min and a peel angle of 180°.

[0042] In one embodiment, the curing temperature of the pressure-sensitive adhesive layer is higher than the glass transition temperature (Tg) of the second (meth)acrylate resin.

[0043] If the curing temperature is higher than the glass transition temperature (Tg) of the second (meth)acrylate resin, the mobility of the second (meth)acrylate resin increases during the curing process, and the second (meth)acrylate resin that rises to the surface of the adhesive layer can penetrate between the first (meth)acrylate resin particles, thereby realizing the adhesive strength of the first (meth)acrylate resin on the surface of the adhesive layer after curing.

[0044] In one embodiment, the curing temperature of the pressure-sensitive adhesive layer is higher than the melting temperature (Tm) of the second (meth)acrylate resin.

[0045] If the curing temperature is higher than the melting temperature (Tm) of the second (meth)acrylate resin, the mobility of the second (meth)acrylate resin can be further increased during the curing process, thereby increasing the difference in adhesive strength between before and after curing of the adhesive layer.

[0046] If the adhesive strength of the first (meth)acrylate resin after curing is greater than the adhesive strength of the second (meth)acrylate resin before curing, the adhesive strength of the adhesive layer before curing can be realized to be close to the adhesive strength of the second (meth)acrylate resin before curing, and the adhesive strength of the adhesive layer after curing can be realized to be close to the adhesive strength of the first (meth)acrylate resin after curing. Therefore, the adhesive strength of the adhesive layer after curing can be increased compared to the adhesive strength before curing.

[0047] In one embodiment, the viscosity of the second (meth)acrylate resin is lower than the viscosity of the first (meth)acrylate resin.

[0048] An adhesive layer formed from the adhesive composition of the present application can be used to bond an organic light emitting device (OLED) to a touch screen. The adhesive layer is first bonded to the surface of the OLED, particularly to the encapsulant layer. At this time, the adhesive layer is in an uncured state. The adhesive layer before curing has low adhesion to the surface of the encapsulant layer, allowing for a half-cut process of the adhesive portion.

[0049] After that, a touch screen is attached to the adhesive layer, and the adhesive layer is cured to increase its adhesive strength. Therefore, when mass-producing organic light-emitting element panels, there is no need to use a protective film for the encapsulant layer, and there is no need for a separate OCA (Optically Clear Adhesive).

[0050] In one embodiment, the first (meth)acrylate resin has a glass transition temperature (Tg) of 20°C or lower; 10°C or lower; 0°C or lower; or -10°C or lower.

[0051] In the pressure-sensitive adhesive composition of the present invention, the lower limit of the glass transition temperature (Tg) of the first (meth)acrylate resin can be selected appropriately.

[0052] In one embodiment, the glass transition temperature of the first (meth)acrylate resin may be, but is not limited to, -80°C or higher; -70°C or higher; or -60°C or higher.

[0053] In one embodiment, the melting temperature (Tm) of the second (meth)acrylate resin is 60°C or lower; 55°C or lower; or 55°C or lower.

[0054] In one embodiment, the melting temperature (Tm) of the second (meth)acrylate resin is 20°C or higher; 25°C or higher; 30°C or higher; or 35°C or higher.

[0055] In one embodiment, the second (meth)acrylate resin has a glass transition temperature (Tg) of 50°C or lower; 45°C or lower; or 40°C or lower.

[0056] In one embodiment, the second (meth)acrylate resin has a glass transition temperature (Tg) of 20°C or higher; 25°C or higher; or 30°C or higher.

[0057] The second (meth)acrylate resin and the first (meth)acrylate resin can be used by appropriately selecting physical properties such as molecular weight within the limits that satisfy the above-mentioned conditions.

[0058] In one embodiment, the weight average molecular weight of the first (meth)acrylate resin is 500,000 g / mol to 900,000 g / mol. If the molecular weight of the first (meth)acrylate resin is less than this range, the adhesive strength of the pressure-sensitive adhesive layer before curing may be high, and if it exceeds this range, the adhesive strength of the pressure-sensitive adhesive layer after curing may be low, so it is preferable that the weight average molecular weight satisfies this range.

[0059] In one embodiment, the weight average molecular weight of the first (meth)acrylate resin is 500,000 g / mol or greater; 550,000 g / mol or greater; or 600,000 g / mol or greater.

[0060] In one embodiment, the weight average molecular weight of the first (meth)acrylate resin is 900,000 g / mol or less; 850,000 g / mol or less; or 800,000 g / mol or less.

[0061] In one embodiment, the weight average molecular weight of the second (meth)acrylate resin is 20,000 g / mol to 80,000 g / mol. If the molecular weight of the second (meth)acrylate resin is less than this range, the adhesive strength of the pressure-sensitive adhesive layer before curing may be high, and if it exceeds this range, the adhesive strength of the pressure-sensitive adhesive layer after curing may be low, so it is preferable that the weight average molecular weight satisfies this range.

[0062] In one embodiment, the weight average molecular weight of the second (meth)acrylate resin is 20,000 g / mol or greater; 25,000 g / mol or greater; or 30,000 g / mol or greater.

[0063] In one embodiment, the weight average molecular weight of the second (meth)acrylate resin is 80,000 g / mol or less; 75,000 g / mol or less; or 70,000 g / mol or less.

[0064] In this specification, the weight average molecular weight is a value obtained by averaging the molecular weights of individual polymer compounds by weight fraction when the molecular weights of the polymer compounds are not uniform.

[0065] The weight average molecular weight may refer to a value converted to standard polystyrene measured using gel permeation chromatography (GPC), etc.

[0066] The second (meth)acrylate resin is contained in an amount of 1 to 10 parts by weight relative to 100 parts by weight of the first (meth)acrylate resin. If the second (meth)acrylate resin is contained in an amount less than the above amount, the adhesive strength of the adhesive layer before curing may be high, and if the second (meth)acrylate resin is contained in an amount exceeding the above amount, the adhesive strength of the adhesive layer after curing may be low.

[0067] In one embodiment, the second (meth)acrylate resin is included in an amount, per 100 parts by weight of the first (meth)acrylate resin, of 10 parts by weight or less; 8 parts by weight or less; 5 parts by weight or less; or 4 parts by weight or less.

[0068] In one embodiment, the second (meth)acrylate resin is included in an amount of 1 part by weight or more; or 2 parts by weight or more, based on 100 parts by weight of the first (meth)acrylate resin.

[0069] As the first (meth)acrylate resin and the second (meth)acrylate resin, any (meth)acrylate resin can be appropriately selected and used as long as the melting temperature (Tm) of the second (meth)acrylate resin is at least 20°C higher than the glass transition temperature (Tg) of the first (meth)acrylate resin.

[0070] In this specification, (meth)acrylate includes both acrylate and methacrylate.

[0071] The first and second (meth)acrylate resins may be a random copolymer in which monomers are randomly mixed together, a block copolymer in which aligned blocks are repeated at regular intervals, or an alternating copolymer in which monomers are alternately polymerized.

[0072] The first and second (meth)acrylate resins can be prepared by a polymerization method commonly used in the art, such as solution polymerization, photopolymerization, bulk polymerization, suspension polymerization, or emulsion polymerization.

[0073] In one embodiment, the first (meth)acrylate resin may be a copolymer of (meth)acrylate monomers.

[0074] In one embodiment, the first (meth)acrylate resin may further include a crosslinkable functional group-containing monomer as a monomer unit.

[0075] The crosslinkable functional group-containing monomer refers to, for example, a monomer that can be polymerized with the (meth)acrylate monomer and can provide a crosslinkable functional group to the (meth)acrylate resin after polymerization.

[0076] The crosslinkable functional group may be, but is not limited to, a hydroxyl group, a carboxyl group, an epoxy group, an amide group, an amine group, an oxetanyl group, an isocyanate group, or a nitrogen-containing functional group.

[0077] The crosslinkable functional group-containing monomer may include, but is not limited to, one or more selected from the group consisting of hydroxyl group-containing monomers, carboxyl group-containing monomers, epoxy group-containing monomers, amide group-containing monomers, amine group-containing monomers, oxetanyl group-containing monomers, glycidyl group-containing monomers, isocyanate group-containing monomers, and nitrogen-containing functional group-containing monomers.

[0078] In one embodiment, the crosslinkable functional group-containing monomer may be a hydroxy group-containing monomer; or a carboxyl group-containing monomer.

[0079] The hydroxy group-containing monomer may be, but is not limited to, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 2-hydroxyethylene glycol (meth)acrylate, 2-hydroxypropylene glycol (meth)acrylate, 2-hydroxyethylene glycol (meth)acrylate, 2-hydroxypropylene glycol (meth)acrylate, hydroxyalkylene glycol (meth)acrylates having an alkylene group with 2 to 4 carbon atoms, 4-hydroxybutyl vinyl ether, 5-hydroxypentyl vinyl ether, 6-hydroxyhexyl vinyl ether, 7-hydroxyheptyl vinyl ether, 8-hydroxyoctyl vinyl ether, 9-hydroxynonyl vinyl ether, 10-hydroxydecyl vinyl ether, 2-hydroxymethyl (meth)acrylamide, 2-hydroxyethyl (meth)acrylamide, etc.

[0080] The carboxyl group-containing monomer may be, but is not limited to, (meth)acrylic acid, 2-(meth)acryloyloxyacetic acid, 3-(meth)acryloyloxypropyl acid, 4-(meth)acryloyloxybutyric acid, acrylic acid dimer, itaconic acid, maleic acid, maleic anhydride, etc.

[0081] The epoxy group-containing monomer may be, but is not limited to, glycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 4,5-epoxyhexyl (meth)acrylate, or 6,7-epoxyheptyl (meth)acrylate.

[0082] The amide group-containing monomer may be, but is not limited to, acrylamide, octadecylacrylamide, isopropyl(meth)acrylamide, aminopropyl(meth)acrylamide, [(dimethylamino)propyl](meth)acrylamide, and the like.

[0083] The amine group-containing monomer may be, but is not limited to, allylamine, 2-aminoethyl (meth)acrylate, N-(3-aminopropyl) (meth)acrylamide, and the like.

[0084] The oxetanyl group-containing monomer may be, but is not limited to, 3-(acryloyloxymethyl)-3-methyloxetane, 3-(methacryloyloxymethyl)-3-methyloxetane, 3-(acryloyloxymethyl)-3-ethyloxetane, 3-(methacryloyloxymethyl)-3-ethyloxetane, 3-(acryloyloxymethyl)-3-butyloxetane, 3-(methacryloyloxymethyl)-3-butyloxetane, 3-(acryloyloxymethyl)-3-hexyloxetane, 3-(methacryloyloxymethyl)-3-hexyloxetane, and the like.

[0085] The isocyanate group-containing monomer may be, but is not limited to, 2-isocyanate ethyl (meth)acrylate, 2-isocyanate propyl (meth)acrylate, 4-isocyanate butyl (meth)acrylate, 4-isocyanate pentyl (meth)acrylate, and the like.

[0086] The nitrogen-containing functional group-containing monomer may be, but is not limited to, (meth)acrylonitrile, N-vinylpyrrolidone, N-vinylcaprolactam, and the like.

[0087] In the first (meth)acrylate resin, the content of the crosslinkable functional group-containing monomer is not particularly limited, and can be appropriately selected as long as the first (meth)acrylate resin can achieve the desired melting temperature (Tm) or glass transition temperature (Tg).

[0088] In one embodiment, the second (meth)acrylate resin may be a copolymer of a (meth)acrylate monomer and a polymerizable functional group-containing polyorganosiloxane.

[0089] The polymerizable functional group means an unsaturated functional group that can be polymerized with other monomers that constitute the resin. In one embodiment, the polymerizable functional group in the polymerizable functional group-containing polyorganosiloxane may include one or more selected from the group consisting of an acryloyl group, a methacryloyl group, an acryloyloxy group, and a methacryloyloxy group.

[0090] The polymerizable functional group-containing polyorganosiloxane has one polymerizable functional group. If the polymerizable functional group-containing polyorganosiloxane contains two or more polymerizable functional groups, crosslinking may occur excessively during the polymerization reaction, resulting in the formation of a precipitate that is insoluble in the solvent, making it difficult to recover the resin from the reactor.

[0091] The polymerizable functional group-containing polyorganosiloxane contains a polymerizable functional group at the end of the polyorganosiloxane, which allows the polyorganosiloxane to be present in a side chain of the second (meth)acrylate resin.

[0092] The polymerizable functional group-containing polyorganopolysiloxane may be a compound represented by the following chemical formula 1-1 or 1-2.

[0093] [ka]

[0094] [ka]

[0095] In the above chemical formulas 1-1 and 1-2, R1 to R7 are the same or different and each independently represents an alkyl group; R8 is hydrogen or a methyl group; L is an alkylene group.

[0096] In one embodiment, R1 to R7 are the same or different and each independently represent a C1-C10 alkyl group; a C1-C6 alkyl group; or a C1-C4 alkyl group. In one embodiment, R1 to R7 are each a methyl group. In one embodiment, L is a C1-C15 alkylene group; a C1-C10 alkylene group; or a C1-C6 alkylene group. In one embodiment, L is a straight chain alkylene group.

[0097] The polymerizable functional group-containing polyorganosiloxane may be a commercially available compound, or, for example, X-24-8201, X-22-174DX, X-22-2426, X-22-2404, X-22-164A, and X-22-164C manufactured by Shin-Etsu Chemical Co., Ltd.; BY16-152D, BY16-152, and BY16-152C manufactured by Toray Dow Corning Co., Ltd.; or FM-0711, FM-0721, and FM-0725 manufactured by Chisso.

[0098] In one embodiment, the second (meth)acrylate resin may be a copolymer of 60% by weight to 95% by weight of a (meth)acrylate monomer and 5% by weight to 40% by weight of a polymerizable functional group-containing polyorganosiloxane.

[0099] In one embodiment, the second (meth)acrylate resin may be a copolymer of 70% by weight to 90% by weight of a (meth)acrylate monomer and 10% by weight to 30% by weight of a polymerizable functional group-containing polyorganosiloxane.

[0100] If the amount of the polymerizable functional group-containing polyorganosiloxane contained in the second (meth)acrylate resin is less than the above range, the increase in adhesive strength before and after curing of the adhesive layer will be small, and if the amount is more than the above range, the haze of the adhesive strength will increase and the compatibility of the adhesive layer may decrease.

[0101] In one embodiment, the haze of the pressure-sensitive adhesive layer may be, but is not limited to, 0.5% to 2% and may be, for example, 1.7% or less, 1.5% or less, or 1.3% or less. In the present invention, the haze may be a value measured for light with a wavelength of 380 nm to 780 nm.

[0102] In this specification, haze is the percentage of the transmittance of diffused light relative to the transmittance of total transmitted light passing through the object to be measured. The haze can be evaluated using a haze meter (NDH-5000SP).

[0103] The type of (meth)acrylate monomer copolymerizable with the first (meth)acrylate resin and the second (meth)acrylate resin is not particularly limited, and an appropriate (meth)acrylate monomer can be selected in consideration of the melting temperature (Tm) and glass transition temperature (Tg) of each resin.

[0104] In one embodiment, the (meth)acrylate monomer contained as a monomer unit in the first (meth)acrylate resin and the second (meth)acrylate resin is selected from the group consisting of alkyl (meth)acrylate, aromatic hydrocarbon-containing (meth)acrylate, hydroxyalkyl (meth)acrylate, cyclohexyl (meth)acrylate, phenoxy (meth)acrylate, 2-ethylphenoxy (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, 2-ethylthiophenyl (meth)acrylate, 2-phenylethyl (meth)acrylate, 3-phenylpropyl (meth)acrylate, 4-phenylbutyl (meth)acrylate, 2,2-methylphenylethyl (meth)acrylate, and 2,3-methylphenylethyl (meth)acrylate. The acrylate may be one or more selected from the group consisting of 2-(4-methylphenyl)ethyl (meth)acrylate, 2-(4-propylphenyl)ethyl (meth)acrylate, 2-(4-(1-methylethyl)phenyl)ethyl (meth)acrylate, 2-(4-methoxyphenyl)ethyl (meth)acrylate, 2-(4-cyclohexylphenyl)ethyl (meth)acrylate, 2-(2-chlorophenyl)ethyl (meth)acrylate, 2-(3-chlorophenyl)ethyl (meth)acrylate, 2-(4-chlorophenyl)ethyl (meth)acrylate, 2-(4-bromophenyl)ethyl (meth)acrylate, 2-(3-phenylphenyl)ethyl (meth)acrylate, and 2-(4-benzylphenyl)ethyl (meth)acrylate.

[0105] The alkyl group contained in the alkyl (meth)acrylate may be a straight chain or a branched chain, and the alkyl group may have 1 to 20 carbon atoms. The alkyl (meth)acrylate may include, but is not limited to, one or more selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, sec-butyl (meth)acrylate, pentyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, and stearyl (meth)acrylate.

[0106] The hydroxyalkyl (meth)acrylate may include, but is not limited to, one or more selected from the group consisting of 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, and 2-hydroxyethylene glycol (meth)acrylate.

[0107] The aromatic hydrocarbon-containing (meth)acrylate may include, but is not limited to, one or more selected from the group consisting of ortho-biphenyl (meth)acrylate, meta-biphenyl (meth)acrylate, para-biphenyl (meth)acrylate, 2,6-terphenyl (meth)acrylate, ortho-terphenyl (meth)acrylate, meta-terphenyl (meth)acrylate, para-terphenyl (meth)acrylate, 4-(4-methylphenyl)phenyl (meth)acrylate, 4-(2-methylphenyl)phenyl (meth)acrylate, 2-(4-methylphenyl)phenyl (meth)acrylate, 2-(2-methylphenyl)phenyl (meth)acrylate, 4-(4-ethylphenyl)phenyl (meth)acrylate, 4-(2-ethylphenyl)phenyl (meth)acrylate, 2-(4-ethylphenyl)phenyl (meth)acrylate, and 2-(2-ethylphenyl)phenyl (meth)acrylate.

[0108] In one embodiment, the first (meth)acrylate resin may contain 40% by weight to 80% by weight of alkyl (meth)acrylate and 20% by weight to 60% by weight of hydroxyalkyl (meth)acrylate, relative to 100% by weight of the total monomers constituting the first (meth)acrylate resin.

[0109] In one embodiment, the first (meth)acrylate resin may contain 50% by weight to 80% by weight of alkyl (meth)acrylate and 20% by weight to 50% by weight of hydroxyalkyl (meth)acrylate, relative to 100% by weight of the total monomers constituting the first (meth)acrylate resin.

[0110] In one embodiment, the first (meth)acrylate resin may contain 50% by weight to 70% by weight of alkyl (meth)acrylate and 30% by weight to 50% by weight of hydroxyalkyl (meth)acrylate, relative to 100% by weight of the total monomers constituting the first (meth)acrylate resin.

[0111] In one embodiment, the second (meth)acrylate resin may contain 60% by weight to 95% by weight of alkyl (meth)acrylate and 5% by weight to 40% by weight of a polymerizable functional group-containing polyorganosiloxane, relative to 100% by weight of the total monomers constituting the second (meth)acrylate resin.

[0112] In one embodiment, the second (meth)acrylate resin may contain 60% by weight to 90% by weight of alkyl (meth)acrylate and 10% by weight to 40% by weight of a polymerizable functional group-containing polyorganosiloxane, relative to 100% by weight of the total monomers constituting the second (meth)acrylate resin.

[0113] In one embodiment, the second (meth)acrylate resin may contain 70% by weight to 90% by weight of alkyl (meth)acrylate and 10% by weight to 30% by weight of a polymerizable functional group-containing polyorganosiloxane, relative to 100% by weight of the total monomers constituting the second (meth)acrylate resin.

[0114] When the first and second (meth)acrylate resins have the above composition and content, the desired adhesive strength can be achieved in the adhesive layer later.

[0115] In one embodiment, the pressure-sensitive adhesive composition further comprises a solvent. As the solvent, any commonly used organic solvent can be used without any restrictions, as long as it can dissolve the first and second (meth)acrylate resins.

[0116] The solvent may be, but is not limited to, ethyl acetate, dimethylformamide, diethylformamide, dimethylacetamide, dimethylsulfoxide, tetrahydrofuran (THF), acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, dioxane, cyclohexanone, benzene, toluene, xylene, ethyl acetate, butyl acetate, ethanol, isopropanol, n-butanol, and the like.

[0117] The pressure-sensitive adhesive composition has a solid content concentration of 15% by weight to 50% by weight, 20% by weight to 50% by weight, or 25% by weight to 50% by weight. The solid content concentration (wt%) of the pressure-sensitive adhesive composition means (weight of solid content of pressure-sensitive adhesive composition) / (weight of pressure-sensitive adhesive composition)×100.

[0118] In one embodiment, the viscosity of an ethyl acetate solution of the first (meth)acrylate resin at 25° C. with a solids concentration of 27 wt % is 14,000 cps to 18,000 cps.

[0119] In one embodiment, the viscosity of an ethyl acetate solution of the second (meth)acrylate resin at 25° C. with a solids concentration of 44 wt % is 100 cps to 500 cps.

[0120] In one embodiment of the present specification, the viscosity of the compound can be measured using a viscoelasticity measuring device (Brookfield, DV2T Viscometer). In the present specification, viscosity means the viscosity measured at 25°C unless otherwise specified.

[0121] In this specification, the solid content of the PSA composition means the components remaining after removing the solvent from the PSA composition. In one embodiment, the pressure-sensitive adhesive composition further comprises a thermal curing initiator.

[0122] The thermosetting initiator is used to improve the degree of cure of the adhesive composition, and any known thermosetting initiator can be used without limitation as long as it does not affect the effects of the present invention. For example, SI-60L, SI-80L, SI-100L, SI-150L, ​​etc., manufactured by San-Aid Corporation can be used as the thermosetting initiator.

[0123] The content of the thermosetting initiator may be 0.3 to 1.5 parts by weight, preferably 0.5 to 1 part by weight, and more preferably 0.7 to 1 part by weight, relative to 100 parts by weight of the total weight of the first and second (meth)acrylate resins. In consideration of adhesiveness and liquid stability, the content of the thermosetting initiator is preferably within the above range.

[0124] In one embodiment, the pressure-sensitive adhesive composition may further include a crosslinking agent, which may include, but is not limited to, one or more crosslinking agents selected from the group consisting of an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an aziridine crosslinking agent, and a metal chelate crosslinking agent.

[0125] The isocyanate-based crosslinking agent may be, but is not limited to, tolylene diisocyanate, xylene diisocyanate, 2,4-diphenylmethane diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tetramethylxylene diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, methylene bis triisocyanate, and the like.

[0126] The epoxy-based crosslinking agent may be, but is not limited to, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polytetramethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, resorcinol diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol polyglycidyl ether, and the like.

[0127] The aziridine crosslinker may be, but is not limited to, N,N'-toluene-2,4-bis(1-aziridinecarboxamide), N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), bisisophthaloyl-1-(2-methylaziridine), tri-1-aziridinylphosphine oxide, and the like.

[0128] The metal chelate crosslinker may be, but is not limited to, a compound in which a polyvalent metal such as aluminum, iron, zinc, tin, titanium, antimony, magnesium, and / or vanadium is coordinated with acetylacetone or ethyl acetoacetate.

[0129] In one embodiment, the crosslinking agent is contained in an amount of 0.5 to 10 parts by weight, preferably 0.5 to 5 parts by weight, relative to 100 parts by weight in total of the weights of the first and second (meth)acrylate resins.

[0130] In one embodiment, when the pressure-sensitive adhesive composition further contains a crosslinking agent, the cohesive strength of the pressure-sensitive adhesive can be increased, thereby preventing adhesive residue from occurring in the pressure-sensitive adhesive layer.

[0131] One embodiment of the present application provides an optical film comprising a substrate layer and a pressure-sensitive adhesive layer provided on one surface of the substrate layer, the optical film comprising the pressure-sensitive adhesive composition described above or a cured product thereof.

[0132] In one embodiment, the pressure-sensitive adhesive layer comprises a first (meth)acrylate resin and a second (meth)acrylate resin.

[0133] In one embodiment, 10 mg of the pressure-sensitive adhesive layer of the optical film is taken, placed in an aluminum pan, and attached to a differential scanning calorimeter (DSC Q100, TA Instruments). Heat is then applied from -30°C to 100°C at a heating rate of 20°C / min to measure the heat flow as a function of temperature. Two glass transition temperature (Tg) peaks and two melting temperatures (Tm) can be identified.

[0134] In one embodiment, the optical film may further include a protective layer provided on the surface of the pressure-sensitive adhesive layer opposite to the surface on which the base layer is provided.

[0135] One embodiment of the present application provides an optical film including a base layer, a protective layer, and a pressure-sensitive adhesive layer provided between the base layer and the protective layer, wherein the pressure-sensitive adhesive layer includes the pressure-sensitive adhesive composition described above or a cured product thereof.

[0136] One embodiment of the present application provides a method for manufacturing an optical film, comprising the steps of coating a pressure-sensitive adhesive composition on one surface of a substrate layer and drying the coated pressure-sensitive adhesive composition to form a pressure-sensitive adhesive layer.

[0137] The method for coating the pressure-sensitive adhesive layer may include, but is not limited to, known coating methods such as reverse coating, gravure coating, spin coating, screen coating, fountain coating, dipping, and spraying.

[0138] The coated PSA composition is dried at an appropriate temperature for an appropriate time, such as, but not limited to, an oven at a temperature of 80°C to 150°C for 30 seconds to 5 minutes.

[0139] The method for manufacturing an optical film may further include, after the pressure-sensitive adhesive layer forming step, attaching a protective layer to a surface of the pressure-sensitive adhesive layer opposite to the surface on which the base film is provided.

[0140] In one embodiment, the substrate layer comprises a substrate film. In one embodiment, the protective layer comprises a protective film.

[0141] The types of the base film and the protective film are not particularly limited. Examples of the base film include, but are not limited to, polyethylene terephthalate film, polytetrafluoroethylene film, polyethylene film, polypropylene 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 polyimide film.

[0142] In one embodiment, the base film and the protective film may be polyethylene terephthalate (PET) films. The base film and the protective film may be composed of a single layer or may be a laminate of two or more layers. The thickness of the base film and the protective film can be appropriately selected taking into consideration the object of the present application.

[0143] In one embodiment, the thickness of the substrate film may be 50 μm or more and 125 μm or less, or 60 μm or more and 100 μm or less.

[0144] In one embodiment, the thickness of the protective film may be 25 μm or more and 75 μm or less. One or both surfaces of the base film and the protective film are subjected to a conventional physical or chemical surface treatment such as matte treatment, corona discharge treatment, primer treatment, and crosslinking treatment in order to improve adhesion and retention with the pressure-sensitive adhesive layer or other layers.

[0145] In one embodiment, the thickness of the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition or a cured product thereof may be 50 μm or less, 45 μm or less, or 40 μm or less. The thickness of the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition or a cured product thereof refers to the thickness of the pressure-sensitive adhesive layer before curing.

[0146] In one embodiment, the thickness of the pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition or a cured product thereof may be 15 μm or more; 20 μm or more; or 25 μm or more. If the thickness of the adhesive layer is less than the above range, the unevenness of the panel may not be overcome, and if the thickness exceeds the above range, the cohesive strength of the adhesive layer may be weak, resulting in adhesive residue.

[0147] In one embodiment, the adhesive strength (A) of the adhesive layer comprising the adhesive composition or a cured product thereof is 100 gf / in or less.

[0148] One embodiment of the present application provides an organic electronic device including an organic light-emitting element and a pressure-sensitive adhesive layer in contact with the organic light-emitting element, wherein the pressure-sensitive adhesive layer includes the pressure-sensitive adhesive composition described above; or a cured product thereof.

[0149] In one embodiment, the organic light emitting device includes, in order, a back plate, a plastic substrate, a thin film transistor, an organic light emitting diode, and an encapsulation layer.

[0150] In one embodiment, the adhesive layer is provided on the sealing layer of the organic light-emitting element. In one embodiment, the adhesive layer is provided in contact with the sealing layer of the organic light-emitting element.

[0151] One embodiment of the present application provides a method for manufacturing an organic electronic device, including a step of attaching the adhesive layer of the optical film to a sealing layer of an organic light emitting device.

[0152] In one embodiment, the method for manufacturing an organic electronic device may further include removing a protective layer from an optical film before attaching the pressure-sensitive adhesive layer to the organic light-emitting device.

[0153] In one embodiment, the method for manufacturing an organic electronic device may further include attaching a touch screen onto the adhesive layer after attaching the adhesive layer to the organic light emitting element.

[0154] In one embodiment, the method for manufacturing an organic electronic device may further include a step of removing a substrate layer from the optical film between the step of attaching the adhesive layer to the organic light-emitting element and the step of attaching a touch screen on the adhesive layer.

[0155] In one embodiment, the method for manufacturing an organic electronic device may further include a step of curing the adhesive layer after the step of attaching a touch screen onto the adhesive layer.

[0156] In one embodiment, the method for curing the pressure-sensitive adhesive composition is not particularly limited, and for example, a curing method using an appropriate heating, drying, and / or aging process can be adopted.

[0157] In one embodiment, the pressure-sensitive adhesive layer is cured using an autoclave at a temperature of 40° C. to 60° C. for 10 minutes to 30 minutes under a pressure of 0.3 MPa to 0.6 MPa. In one embodiment, the pressure-sensitive adhesive layer may further undergo an appropriate aging step after the curing step.

[0158] In one embodiment, the aging step of the pressure-sensitive adhesive layer is carried out for 4 to 6 days at 30° C. to 50° C. In another embodiment, the aging step of the pressure-sensitive adhesive layer is carried out at 40° C. for 5 days.

[0159] One embodiment of the present application provides a display device including an organic light-emitting element, a touch screen, and an adhesive layer bonding the organic light-emitting element and the touch screen, wherein the adhesive layer includes the adhesive composition described above; or a cured product thereof.

[0160] In this specification, the cured product of the pressure-sensitive adhesive composition refers to a substance obtained by pressing a mixture of a first (meth)acrylate resin and a second (meth)acrylate resin in an autoclave at a temperature of 40°C to 60°C for a time of 10 minutes to 30 minutes at a pressure of 0.3 MPa to 0.6 MPa.

[0161] In one embodiment, the cured product of the pressure-sensitive adhesive composition may refer to a substance obtained by pressing a mixture of the first (meth)acrylate and the second (meth)acrylate resins at 0.5 MPa for 20 minutes at a temperature of 50°C using an autoclave.

[0162] In one embodiment, the touch screen sequentially comprises a touch sensor film; a polarizer; and a cover window.

[0163] In one embodiment, the adhesive layer is provided on the touch sensor film of the touch screen.

[0164] In one embodiment, the adhesive layer is provided in contact with the touch sensor film of the touch screen.

[0165] In one embodiment of the present specification, the optical transmittance in the visible light region of the pressure-sensitive adhesive layer containing the cured product of the pressure-sensitive adhesive composition described above is 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more.

[0166] In this specification, the visible light region means a wavelength range of 380 nm to 780 nm.

[0167] In one embodiment, the light transmittance can be measured using a spectrophotometer (n&k spectrometer, manufactured by n&k Technology).

[0168] In one embodiment of the present specification, the thickness of the pressure-sensitive adhesive composition after curing is ±0.1% or less of the thickness before curing.

[0169] In one embodiment, the adhesive strength (B) of the pressure-sensitive adhesive layer comprising the cured product of the pressure-sensitive adhesive composition is 800 gf / in or more; 1,000 gf / in or more; 1,500 gf / in or more; 2,000 gf / in or more; or 2,500 gf / in or more.

[0170] Although the use of the pressure-sensitive adhesive composition in an organic light-emitting element has been described above, the use of the pressure-sensitive adhesive composition of the present invention is not limited to the above use, and the pressure-sensitive adhesive composition can also be used for surface protection of adherends or bonding to other components in the manufacturing process of organic photoelectric elements, organic transistors, organic solar cells, etc. [Example]

[0171] While the present invention may be embodied in many different forms, it is not intended to be limited to the embodiments set forth herein, and all such modifications and variations are within the scope of the appended claims.

[0172] <Production example> <Production Example 1-1> Polymerization of (meth)acrylate resin 1-1 A 1-L reactor equipped with a cooling device for easy temperature control and nitrogen gas reflux was charged with a monomer mixture consisting of 8 parts by weight of methyl methacrylate (MMA) and 22 parts by weight of 2-ethylhexyl acrylate (2-EHA), followed by ethyl acetate (EAc) to achieve a solids concentration of 27% by weight. Nitrogen gas was then purged for approximately 1 hour, and the reactor temperature was maintained at 80°C. After homogenizing the mixture, 3 parts by weight of azobisisobutronitrile (AIBN) was added as a reaction initiator per 100 parts by weight of the monomer mixture, and the mixture was reacted. After the reaction, the ethyl acetate was diluted to produce Resin 1-1 with a weight-average molecular weight of 700,000 g / mol.

[0173] <Production Example 1-2> Polymerization of (meth)acrylate resin 1-2 Resin 1-2 having a molecular weight of 700,000 g / mol was prepared in the same manner as in Preparation Example 1-1, except that the amounts of methyl methacrylate (MMA) and 2-ethylhexyl acrylate (2-EHA) were 9 parts by weight and 26 parts by weight, respectively.

[0174] <Production Example 1-3> Polymerization of (meth)acrylate resin 1-3 Resin 1-3 having a molecular weight of 700,000 g / mol was prepared in the same manner as in Preparation Example 1-1, except that the amounts of methyl methacrylate (MMA) and 2-ethylhexyl acrylate (2-EHA) were 5 parts by weight and 25 parts by weight, respectively.

[0175] <Production Example 1-4> Polymerization of (meth)acrylate resin 1-4 Resin 1-4 having a molecular weight of 700,000 g / mol was prepared in the same manner as in Preparation Example 1-1, except that the amounts of methyl methacrylate (MMA) and 2-ethylhexyl acrylate (2-EHA) were 20 parts by weight and 10 parts by weight, respectively.

[0176] <Production Example 2-1> Polymerization of (meth)acrylate resin 2-1 A 1-L reactor equipped with a cooling device for easy temperature control and nitrogen gas reflux was charged with a monomer mixture consisting of 20 parts by weight of polyorganosiloxane (FM-0721, Chisso), 20 parts by weight of methyl methacrylate (MMA), and 60 parts by weight of 2-ethylhexyl methacrylate. Ethyl acetate (EAc) was then added to achieve a solids concentration of 44% by weight. After purging with nitrogen gas for approximately 1 hour, the reactor temperature was maintained at 100°C. After homogenizing the mixture, 5 parts by weight of azobisisobutronitrile (AIBN) per 100 parts by weight of the monomer mixture was added and the mixture was reacted. After the reaction, the ethyl acetate was diluted to produce Resin 2-1 with a weight-average molecular weight of 50,000 g / mol.

[0177] <Production Example 2-2> Polymerization of (meth)acrylate resin 2-2 Resin 2-2 having a molecular weight of 50,000 g / mol was prepared in the same manner as in Preparation Example 2-1, except that 20 parts by weight of polyorganosiloxane (FM-0721, Chisso) and 80 parts by weight of stearyl methacrylate (STMA) were used instead of polyorganosiloxane, methyl methacrylate (MMA), and 2-ethylhexyl methacrylate.

[0178] The glass transition temperatures (Tg) of Resins 1-1 to 1-4 and the melting temperatures (Tm) of Resins 2-1 and 2-2 were measured by the following method. The results are shown in Table 1.

[0179] Glass transition temperature (Tg) measurement Using a differential scanning calorimeter (DSC Q100, TA Instruments), an aluminum pan containing 10 mg of resin was attached to the instrument. Heat was applied from -30°C to 100°C at a heating rate of 20°C / min, and the heat flow was measured as a function of temperature. The midpoint between the temperature at which the heat flow began to change and the temperature at which the change ended was taken as the glass transition temperature (Tg).

[0180] Melting temperature (Tm) measurement Using a differential scanning calorimeter (DSC Q100, TA Instruments), an aluminum pan containing 10 mg of resin was attached to the instrument. Heat was applied from -30°C to 100°C at a heating rate of 20°C / min, and the heat flow was measured as a function of temperature. The temperature at which the heat flow was at its maximum in the temperature range where endothermic heat occurred after the glass transition temperature (Tg) appeared was defined as the melting temperature (Tm).

[0181] [Table 1]

[0182] Example 1 A pressure-sensitive adhesive composition was prepared by mixing 30 parts by weight of Resin 1-1, 1 part by weight of Resin 2-1, and 20 parts by weight of toluene.

[0183] <Examples 2 and 3 and Comparative Example 1> Pressure-sensitive adhesive compositions were produced in the same manner as in Example 1, except that the resins listed in Table 2 below were used. The adhesive strength before curing (adhesive strength A) and the adhesive strength after curing (adhesive strength B) of the adhesive compositions of Examples 1 to 3 and Comparative Example 1 were measured, and the results are shown in Table 2 below.

[0184] Optical film manufacturing A 75 μm thick polyethylene terephthalate (PET) film (AF34V, SKCHMT) was prepared as a substrate film. The adhesive composition was then coated onto the substrate film and dried in an oven at 110° C. for 2 minutes to prepare an adhesive layer with a thickness of 25 μm. Next, a 50 μm thick polyethylene terephthalate (PET) film (RF12ASW, SKCHMT) (protective layer) was attached to one side of the pressure-sensitive adhesive layer to produce an optical film.

[0185] How to measure adhesive strength (A) The optical film was cut into a width of 25 mm and a length of 210 mm to prepare a test specimen. The protective layer was peeled off from the prepared optical film at a peel angle of 180° and a peel rate of 1.8 m / min, and the pressure-sensitive adhesive layer of the test specimen was attached to a stainless steel plate (JIS SUS304) using a 2 kg roller. After storing the test specimen at a temperature of 25°C and a relative humidity of 50% for 30 minutes, the peel strength (adhesion strength (A)) was measured when the pressure-sensitive adhesive layer was peeled off from the stainless steel plate at a peel angle of 180° and a peel rate of 0.3 m / min using a tensile tester (Texture Analyzer, Stable Microsystems, UK).

[0186] Adhesive strength (B) measurement method The optical film was cut into a 25 nm wide, 210 mm long specimen. The protective layer was peeled off from the optical film at a peel angle of 180° and a peel rate of 1.8 m / min, and the pressure-sensitive adhesive layer of the specimen was attached to a stainless steel plate (JIS standard SUS304) using a 2 kg roller. The specimen was then autoclaved at 50°C and 0.5 MPa for 20 minutes. After storing the specimen at 25°C and 50% relative humidity for 30 minutes, the peel strength (adhesion strength (B)) of the pressure-sensitive adhesive layer was measured using a tensile tester (Texture Analyzer, Stable Microsystems, UK) when peeled off from the stainless steel plate at a peel angle of 180° and a peel rate of 0.3 m / min.

[0187] [Table 2]

[0188] The adhesive strength (A) and adhesive strength (B) in Table 2 were each measured twice and are shown in Table 2. (Measured value from one measurement / measured value from two measurements) In Table 2, it can be seen that when there is a difference of 20°C or more between the glass transition temperature of the first resin and the melting temperature of the second resin, the adhesive strength of the adhesive layer is 100 gf / in or less before curing and 800 gf / in or more after curing.

Claims

1. A pressure-sensitive adhesive composition comprising a first (meth)acrylate resin and a second (meth)acrylate resin, the weight average molecular weight of the first (meth)acrylate resin is 500,000 g / mol to 900,000 g / mol; the weight average molecular weight of the second (meth)acrylate resin is 20,000 g / mol to 80,000 g / mol; The weight average molecular weight of the second (meth)acrylate resin is lower than the weight average molecular weight of the first (meth)acrylate resin. the first (meth)acrylate resin is a copolymer of (meth)acrylate monomers, the second (meth)acrylate resin is a copolymer of a (meth)acrylate monomer and a polymerizable functional group-containing polyorganosiloxane; the second (meth)acrylate resin is contained in an amount of 4 parts by weight or less relative to 100 parts by weight of the first (meth)acrylate resin; The melting temperature (Tm) of the second (meth)acrylate resin is higher by 20°C or more than the glass transition temperature (Tg) of the first (meth)acrylate resin. When the pressure-sensitive adhesive composition is coated on a polyethylene terephthalate (PET) film and dried at 110°C for 2 minutes to form a pressure-sensitive adhesive layer having a thickness of 25 μm, the pressure-sensitive adhesive layer has an adhesive strength of 100 gf / in or less before curing when peeled from a stainless steel plate (JIS SUS304) at a peel speed of 0.3 m / min and a peel angle of 180°, The pressure-sensitive adhesive composition is coated on a polyethylene terephthalate (PET) film and dried at 110°C for 2 minutes to form a pressure-sensitive adhesive layer having a thickness of 25 μm. The pressure-sensitive adhesive layer is then cured for 20 minutes under conditions of 50°C and 0.5 MPa, and stored for 30 minutes under conditions of a temperature of 25°C and a relative humidity of 50%. When the pressure-sensitive adhesive layer is peeled from a stainless steel plate (JIS SUS304) at a peel speed of 0.3 m / min and a peel angle of 180°, the adhesive strength of the pressure-sensitive adhesive composition after curing is 800 gf / in or more, the curing temperature of the pressure-sensitive adhesive layer is higher than the glass transition temperature and the melting temperature of the second (meth)acrylate resin; Pressure-sensitive adhesive composition.

2. The pressure-sensitive adhesive composition according to claim 1 , wherein the melting temperature (Tm) of the second (meth)acrylate resin is higher than the glass transition temperature (Tg) of the first (meth)acrylate resin by 50° C. or more.

3. An optical film comprising a base layer and a pressure-sensitive adhesive layer provided on one surface of the base layer, The pressure-sensitive adhesive layer comprises the pressure-sensitive adhesive composition according to claim 1 or a cured product thereof.

4. The optical film according to claim 3 , further comprising a protective layer provided on a surface of the pressure-sensitive adhesive layer opposite to the surface on which the base layer is provided.

5. An organic electronic device comprising an organic light-emitting element and a pressure-sensitive adhesive layer in contact with the organic light-emitting element, The pressure-sensitive adhesive layer comprises the pressure-sensitive adhesive composition according to claim 1 ; or a cured product thereof.

6. A display device including an organic light-emitting element, a touch screen, and an adhesive layer that bonds the organic light-emitting element and the touch screen, The pressure-sensitive adhesive layer comprises the pressure-sensitive adhesive composition according to claim 1 ; or a cured product thereof.

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