KR101955755B1 - Adhesive film, adhesive composition for the same, optical member comprising the same and optical display apparatus comprising the same - Google Patents

Abstract

(Meth) acryl-based copolymer having a hydroxyl group, an initiator and a silane coupling agent, wherein the reduction ratio of the peel strength of formula (1) is 10% or less, a pressure-sensitive adhesive composition therefor, An optical display device is provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pressure-sensitive adhesive film, an adhesive composition for the same, an optical member including the same, and an optical display device including the adhesive member.

The present invention relates to a pressure-sensitive adhesive film, a pressure-sensitive adhesive composition therefor, an optical member including the pressure-sensitive adhesive composition, and an optical display device including the same.

The optical display device includes a display element including a window film, a conductive film, and an organic light emitting element. In an optical display device, various display devices can be adhered by an optical clear adhesive (OCA). Recently, a flexible optical display device has been developed as an optical display device. Therefore, the adhesive film should be free from bubbles or peeling in a state of high temperature and high humidity for a predetermined period or under repeated bending conditions at high temperature and high humidity, and should have good foldability.

Since the adhesive film is used in an optical display device, the peel strength should be high not only at room temperature but also at high temperature. However, even in the case of a pressure-sensitive adhesive film having a high peeling strength at room temperature, the peeling strength is lowered at a high temperature. The adhesive film having a high difference in peel strength or storage modulus between high temperature, normal temperature or low temperature may deteriorate the reliability of the optical display device.

The background art of the present invention is disclosed in Korean Patent Publication No. 2007-0055363.

A problem to be solved by the present invention is to provide an adhesive film excellent in reliability even in a repeated bending state at high temperature and high humidity.

Another problem to be solved by the present invention is to provide an adhesive film capable of lowering peel strength at high temperature and high humidity relative to room temperature.

Another problem to be solved by the present invention is to provide a pressure-sensitive adhesive film having high modulus at a low temperature to a high temperature and having good durability and reliability.

Another object of the present invention is to provide a pressure-sensitive adhesive film having good foldability.

Another object of the present invention is to provide an adhesive film that is optically transparent and can be used in an optical display device.

The adhesive film of the present invention comprises a (meth) acrylic copolymer having a hydroxyl group, an initiator and a silane coupling agent, and the reduction ratio of the peel strength in the following formula (1) may be 10% or less:

<Formula 1>

Reduction ratio of peel strength = | B - A | / A x 100

(In the above formula 1, A and B are as defined in the detailed description of the present invention).

The optical member of the present invention may include an optical film and the adhesive film formed on at least one side of the optical film.

The optical display device of the present invention may include the above-mentioned pressure-sensitive adhesive film.

The present invention provides an adhesive film excellent in reliability even in a high-temperature, high-humidity and bending state.

The present invention provides a pressure-sensitive adhesive film capable of lowering peel strength reduction at high temperature and high humidity relative to room temperature.

The present invention provides a pressure-sensitive adhesive film having a high modulus at a low temperature to a high temperature and having excellent durability and reliability.

The present invention provides a pressure-sensitive adhesive film having good foldability.

The present invention provides an adhesive film which is optically transparent and can be used in an optical display device.

1 is a cross-sectional view of an optical display device according to an embodiment of the present invention.

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

The terms "upper" and "lower" in this specification are defined with reference to the drawings, wherein "upper" may be changed to "lower", "lower" What is referred to as " on " may include not only superposition, but also intervening other structures in the middle. On the other hand, what is referred to as " directly on " or " directly above " As used herein, " (meth) acrylic " may mean acrylic and / or methacrylic.

As used herein, " copolymer " may include oligomers, polymers or resins.

The " average particle diameter " of the organic nanoparticles in the present specification is the particle diameter of the organic nanoparticles expressed by the Z-average value measured by a Zetasizer nano-ZS instrument of Malvern in an aqueous or organic solvent.

In the specification, "A" in the peel strength of the pressure-sensitive adhesive film is measured for a specimen in which a glass plate, an adhesive film (thickness: 50 to 100 m) and a PET film (thickness: 50 to 100 m) are sequentially laminated, The PET film was treated with corona twice (dose: 156 dose) at a dose of 78 doses on one side, so that the corona-treated one side was laminated with the adhesive film. When the PET film was pulled at a rate of 300 mm / min at 25 ° C. using a TA.XT_Plus Texture Analyzer (Stable Micro System) after the sample was left at 25 ° C. for 30 minutes, the PET film started to peel off Peel strength of the starting point. In this specification, " B " of the peel strength of the pressure-sensitive adhesive film in this specification means that the specimen is allowed to stand at 60 DEG C and 93% relative humidity for 3 days and is then measured at 25 DEG C at 300 DEG C using TA.XT_Plus Texture Analyzer (Stable Micro System) / min. &lt; / RTI &gt; The peel strength at the time when the PET film starts peeling off.

The "modulus" of the pressure-sensitive adhesive film in this specification is a storage modulus (G '), and a plurality of pressure-sensitive adhesive films of the prepared sample are laminated and perforated to prepare specimens having a thickness of 500 μm and a diameter of 8 mm, and a shear rate of 1 rad / At a temperature rising rate of 5 deg. C / min from -60 deg. C to 90 deg. C under a load of 300 gf in the specimen using an 8 mm jig under auto strain condition at 1% The modulus was determined at 25 캜 and 80 캜, respectively.

In the present specification, the " folding conditions " are lamination in the order of PET film (thickness: 50 to 125 m) / adhesive film (thickness: 20 to 150 m) / PET film The PET film and the adhesive film were adhered to each other and aged at room temperature (for example, 25 DEG C) for 12 hours and cut into a size of width x length (70 mm x 140 mm) to prepare specimens. , Tesa) to a flexural evaluation equipment (CFT-2000, Covotech). At this time, the PET film was subjected to corona treatment, and then the adhesive film and the corona-treated surface were adhered to each other. Bending the specimen in the longitudinal direction at 60 ° C and 93% relative humidity, bending the specimen at a radius of curvature of 3 mm, 30 cycles per minute, wherein one cycle means bending and spreading the specimen at the radius of curvature, bending and holding for 1 second And 100,000 cycles of bending under the post-stretching condition. As used herein, " good foldability " means that no peeling or bubbling has occurred at the folding site when the folding condition is applied.

Hereinafter, an adhesive film according to an embodiment of the present invention will be described.

The pressure-sensitive adhesive film according to this embodiment (hereinafter referred to as 'pressure-sensitive adhesive film') may include a (meth) acrylic copolymer having a hydroxyl group, an initiator and a silane coupling agent. The adhesive film according to the present embodiment includes a (meth) acrylic copolymer having a hydroxyl group, an initiator, and a silane coupling agent, so that the adhesive film is adhered to the adherend, and then, in a frame having a predetermined radius of curvature, And there is no bubble or peeling even in repeated bending, so that reliability at high temperature and high humidity can be good. In general, when the adhesive film is stuck to the adherend and left in a bending state instead of a flat state at high temperature and high humidity or repeatedly bending, air bubbles or peeling may occur. Such bubbles or peeling may occur on the adherend of the adhesive film Increasing the peel strength is not always solved. Thus, the present invention can improve reliability at high temperature and high humidity described above by including a (meth) acrylic copolymer having a hydroxyl group, an initiator, and a silane coupling agent.

Thus, the pressure-sensitive adhesive film was obtained by adhering the pressure-sensitive adhesive film (thickness: 100 占 퐉) between two corona treated 50 占 퐉 PET substrates with a curvature radius of 3 mm at 60 占 폚 and 93% (one cycle of bending and spreading the adhesive film once in half) at the speed of a cycle of 100,000 cycles or more, the number of cycles in which lifting or bubbling does not occur is 100,000 cycles or more, for example, 100,000 to 200,000 cycles Cycle.

In addition, the pressure-sensitive adhesive film according to the present embodiment has a high peel strength at room temperature and low peel strength reduction ratio at peeling strength at room temperature even after being left at high temperature and high humidity for a predetermined time to improve durability and reliability . Specifically, in the pressure-sensitive adhesive film according to the present embodiment, the reduction ratio of the peel strength in the following formula (1) may be 10% or less, specifically 0% to 10%. The reliability and durability of the pressure-sensitive adhesive film in the above-mentioned range can be favorably used in a flexible device:

<Formula 1>

Reduction ratio of peel strength = | B - A | / A x 100

(In the above formula 1, for the specimen in which the glass plate, the adhesive film, and the PET film are sequentially laminated, A indicates that the specimen is left at 25 DEG C for 30 minutes and then the PET film is peeled from the pressure- The peel strength when peeled off at a speed of 300 mm / min. B: The test piece was allowed to stand at 60 占 폚 and 93% relative humidity for 3 days, and then the PET film was peeled from the adhesive film at a peeling speed of 300 mm / min &Lt; / RTI &gt; Further, in the pressure-sensitive adhesive film of this embodiment, the difference in peel strength in the following formula (2) may be 200 gf / in or less, specifically 30 gf / in to 150 gf / in. The reliability and durability of the pressure-sensitive adhesive film in the above-mentioned range can be favorably used in a flexible device:

<Formula 2>

Difference in peel strength = | B - A |

(In the above formula 2, A and B are as defined in the above formula 1).

B &amp;le; A in Equation 1 and Equation 2.

The adhesive film according to this embodiment has a peel strength of 700 gf / in or more, specifically 900 gf / in or more, specifically 900 gf / in to 3000 gf / in, defined by A in the above-mentioned formulas 1 and 2. In the pressure-sensitive adhesive film according to the present embodiment, the peel strength defined as B in the above-mentioned formulas 1 and 2 may be 900 gf / in or more, specifically 900 gf / in to 3000 gf / in. Within the above range, the durability and the like of the pressure-sensitive adhesive film can be improved.

The pressure-sensitive adhesive film may have a modulus of 20 kPa to 500 kPa, specifically 20 kPa to 100 kPa at 80 ° C. Within this range, high temperature reliability improvement effects can be obtained. The pressure-sensitive adhesive film may have a modulus of 25 kPa to 500 kPa, specifically 30 kPa to 100 kPa at 25 ° C. Within the above range, productivity improvement effect may be obtained. The pressure-sensitive adhesive film may have a modulus of 10 kPa to 500 kPa, specifically 20 kPa to 500 kPa at -20 ° C. Within this range, high temperature reliability improvement effects can be obtained. The adhesive film may have a glass transition temperature (Tg) of -100 ° C to -10 ° C, specifically -70 ° C to -30 ° C. Within this range, folding reliability can be improved.

The adhesive film may have a haze of 1% or less, specifically 0.1% to 0.9% and a total light transmittance of 90% or more, specifically 95% to 99% in a visible light region (e.g., a wavelength of 380 nm to 780 nm). Within this range, optical transparency is good and can be used in optical display devices. The thickness of the adhesive film may be 10 탆 to 300 탆, specifically 15 탆 to 175 탆. In the above range, it can be used in an optical display device.

The adhesive film according to an embodiment of the present invention can be produced by photocuring a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition may include a monomer mixture, a initiator and a silane coupling agent for a (meth) acrylic copolymer having a hydroxyl group. The monomer mixture may be contained in the pressure-sensitive adhesive composition in the state of a monomer mixture in which polymerization is not carried out at all, but the monomer mixture may be contained as a partially polymerized partial polymer.

The monomer mixture may form a (meth) acrylic copolymer having a hydroxyl group. The (meth) acrylic copolymer having a hydroxyl group forms a matrix of the pressure-sensitive adhesive film and can exhibit adhesiveness. The (meth) acrylic copolymer having a hydroxyl group may have a glass transition temperature of -100 ° C to -10 ° C, specifically -70 ° C to -30 ° C. Within the above range, the pressure-sensitive adhesive film has an excellent adhesive strength and reliability in a wide temperature range. The (meth) acrylic copolymer having a hydroxyl group may have a refractive index of 1.40 to 1.70, specifically 1.45 to 1.60. Within this range, transparency can be maintained when laminated with other optical films. The monomer mixture may include a hydroxyl group-containing (meth) acrylate and an alkyl group-containing (meth) acrylate.

The hydroxyl group-containing (meth) acrylate can provide the adhesive force of the adhesive film. The hydroxyl group-containing (meth) acrylate may be a (meth) acrylate containing at least one hydroxyl group. For example, the hydroxyl group-containing (meth) acrylate may be at least one selected from the group consisting of 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl Cyclohexanedimethanol mono (meth) acrylate, 1-chloro-2-hydroxypropyl (meth) acrylate, diethylene glycol (meth) acrylate, (Meth) acrylate, neopentylglycol mono (meth) acrylate, dipentaerythritol penta (meth) acrylate, neopentyl glycol mono (meth) acrylate, (Meth) acrylate, 4-hydroxycyclopentyl (meth) acrylate, 4-hydroxycyclopentyl (meth) acrylate, trimethylolpropane di - hydroxycyclohexyl (meth) One kind of acrylate and cyclohexanedimethanol mono (meth) acrylate may be at least. The hydroxyl group-containing (meth) acrylate may be included in the monomer mixture in an amount of 5 wt% to 40 wt%, for example, 10 wt% to 30 wt%, 10 wt% to 25 wt%, and 15 wt% to 25 wt% . The adhesive strength and endurance reliability of the adhesive film can be further improved in the above range.

The alkyl group-containing (meth) acrylate can form a matrix of an adhesive film. The alkyl group-containing (meth) acrylate may include an unsubstituted linear or branched alkyl (meth) acrylate having 1 to 20 carbon atoms. (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, (Meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, ethylhexyl (meth) acrylate, octyl (Meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, and isobonyl (meth) acrylate. The alkyl group-containing (meth) acrylate may be present in the monomer mixture in an amount ranging from 55% to 90%, such as 60% to 95%, 70% to 90%, 75% to 90% To 85% by weight. The adhesive strength and endurance reliability of the adhesive film can be further improved in the above range.

In one embodiment, the monomer mixture comprises 5% by weight to 40% by weight of a hydroxyl group-containing (meth) acrylate in the total of the hydroxyl group-containing (meth) acrylate and the alkyl group-containing (meth) % To 95% by weight. Within this range, folding reliability can be improved.

The monomer mixture may further comprise copolymerizable monomers. The copolymerizable monomer may be contained in the (meth) acrylic copolymer to provide additional effects to the (meth) acrylic copolymer, the pressure sensitive adhesive composition or the pressure sensitive adhesive film. The copolymerizable monomer is a monomer having an ethylene oxide, a monomer having propylene oxide, a monomer having an amine group, a monomer having an alkoxy group, a monomer having a phosphoric acid group, or a monomer having an alkyl group (meth) , A monomer having a sulfonic acid group, a monomer having a phenyl group, a monomer having a silane group, a monomer having a carboxylic acid group, and an amide group-containing (meth) acrylate.

As the monomer having an ethylene oxide, one or more (meth) acrylate monomers containing an ethylene oxide group (-CH ₂ CH ₂ O-) may be used. (Meth) acrylate, polyethylene oxide monoethyl ether (meth) acrylate, polyethylene oxide monopropyl ether (meth) acrylate, polyethylene oxide monobutyl ether (meth) acrylate, polyethylene oxide mono (Meth) acrylate, polyethylene oxide monoisobutyl ether (meth) acrylate, polyethylene oxide diethyl ether (meth) acrylate, polyethylene oxide monoisopropyl ether (meth) acrylate, polyethylene oxide monoisobutyl ether (Meth) acrylate such as polyethylene oxide mono-t-butyl ether (meth) acrylate, but is not limited thereto.

The monomer having propylene oxide is at least one monomer selected from the group consisting of polypropylene oxide monomethyl ether (meth) acrylate, polypropylene oxide monoethyl ether (meth) acrylate, polypropylene oxide monopropyl ether (meth) acrylate, polypropylene oxide monobutyl ether (Meth) acrylate, polypropylene oxide diethyl ether (meth) acrylate, polypropylene oxide monoisopropyl ether (meth) acrylate, polypropylene oxide dimethyl ether (Meth) acrylate such as polypropylene oxide monoisobutyl ether (meth) acrylate, polypropylene oxide mono butyl ether (meth) acrylate, and the like, but is not limited thereto no All.

Monomers having an amine group include monomethylaminoethyl (meth) acrylate, monoethylaminoethyl (meth) acrylate, monomethylaminopropyl (meth) acrylate, monoethylaminopropyl (meth) acrylate, dimethylaminoethyl (Meth) acrylate monomer such as diethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, N-tert-butylaminoethyl (meth) acrylate and methacryloxyethyltrimethylammonium chloride But is not necessarily limited thereto.

Examples of the monomer having an alkoxy group include 2-methoxyethyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, 2-ethoxypropyl (meth) (Meth) acrylate, methoxypentyl (meth) acrylate, 3-ethoxypentyl (meth) acrylate, 2-ethoxypentyl ) Acrylate, 3-butoxyhexyl (meth) acrylate, and the like.

Monomers having a phosphoric acid group include monomers such as 2-methacryloyloxyethyldiphenyl phosphate (meth) acrylate, trimethacryloyloxyethylphosphate (meth) acrylate, triacryloyloxyethylphosphate (meth) Acrylic monomer having a phosphoric acid group, but the present invention is not limited thereto.

The monomer having a sulfonic acid group may be an acrylic monomer having a sulfonic acid group such as sodium sulfopropyl (meth) acrylate, sodium 2-sulfoethyl (meth) acrylate, and sodium 2-acrylamido-2-methylpropane sulfonate But is not necessarily limited thereto.

The monomer having a phenyl group can be an acrylic vinyl monomer having a phenyl group such as p-tert-butylphenyl (meth) acrylate, o-biphenyl (meth) acrylate and phenoxyethyl (meth) acrylate, It is not.

The monomer having a silane group may be selected from the group consisting of 2-acetoacetoxyethyl (meth) acrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethyl) silane, vinyltriacetoxysilane, Butoxypropyltrimethoxysilane, and the like, but is not limited thereto.

The monomer having a carboxylic acid group may be at least one monomer selected from the group consisting of (meth) acrylic acid, 2-carboxyethyl (meth) acrylate, 3-carboxypropyl (meth) acrylate, 4-carboxybutyl (meth) acrylate, itaconic acid, Maleic anhydride, and the like, but are not necessarily limited thereto.

The amide group-containing (meth) acrylate is at least one compound selected from the group consisting of (meth) acrylamide, N-methyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (Meth) acrylamide, N-hydroxyethyl (meth) acrylamide and N, N-diethyl (meth) acrylamide. Particularly, N-hydroxyethyl (meth) acrylamide and N, N-diethyl (meth) acrylamide are excellent in the effect of the present invention and can be obtained by reacting an alkyl group- containing (meth) May have an excellent effect of compatibility with the water.

The copolymerizable monomer may be contained in the monomer mixture in an amount of 10 wt% or less, specifically 7 wt% or less, more specifically 0.1 wt% to 10 wt%. In the above range, the pressure-sensitive adhesive composition can further improve the adhesive strength and durability of the pressure-sensitive adhesive film. In particular, the monomer having a carboxylic acid group may be contained in the monomer mixture in an amount of 10 wt% or less, specifically 5 wt% or less, more specifically 1 wt% or less. In the above range, the pressure-sensitive adhesive composition can further improve the adhesive strength and durability of the pressure-sensitive adhesive film.

Initiators can be used to cure (partially polymerize) the monomer mixture into a (meth) acrylic copolymer or to cure a viscous liquid into a film. The initiator may include at least one of a photopolymerization initiator and a thermal polymerization initiator.

As the photopolymerization initiator, any of them can be used as long as it can induce the polymerization reaction of the radically polymerizable compound described below in a curing process by light irradiation or the like to realize the second crosslinking structure. For example, benzoin, hydroxy ketone, amino ketone or phosphine oxide photoinitiators can be used. Specific examples thereof include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether , Benzoin n-butyl ether, benzoin isobutyl ether, 2,2-dimethoxy-2-phenylacetophenone, 2,2'-diethoxyacetophenone, 2,2'-dibutoxyacetophenone, Acetophenone compounds such as hydroxy-2-methylpropiophenone, pt-butyl trichloroacetophenone, pt-butyldichloroacetophenone, 4-chloroacetophenone, 2,2'-dichloro-4- phenoxyacetophenone, Diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2- 2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2- - (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4- 2-ethyl anthraquinone, 2-t-butyl anthraquinone, 2-amino anthraquinone, thioxanthone, 2-ethylthioxanthone, 2- 2-methyl-1 - [(2-hydroxy-2-methyl-1- &lt; / RTI &gt; methyl) benzoic acid ester, 4- (1-methylvinyl) phenyl] propanone] and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide. In the present application, one kind or more kinds of the above can be used, but the present invention is not limited thereto.

The thermal polymerization initiator is not particularly limited as long as it has the above-mentioned physical properties, and for example, ordinary initiators such as an azo-based compound, a peroxide-based compound or a redox-based compound can be used. Examples of the azo compound include 2,2-azobis (2-methylbutyronitrile), 2,2-triyl azo bis (isobutyronitrile), 2,2-triazabis 2-methyl azo bis (2-methylpropionate) and 2,2-phylazobis (4- (4-methoxyphenyl) Methoxy-2,4-dimethylvaleronitrile), and the like, and examples of the peroxide compound include inorganic peroxides such as potassium persulfate, ammonium persulfate or hydrogen peroxide; Or peroxydicarbonate, peroxydicarbonate, peroxy ester, tetramethyl butyl peroxyneodecanoate, bis (4-butylcyclohexyl) peroxydicarbonate, di (2-ethylhexyl) peroxycarbonate, Hexyl peroxy dicarbonate, dimethoxy butyl peroxy dicarbonate, hexyl peroxy dicarbonate, hexyl peroxy dicarbonate, diisopropyl peroxy dicarbonate, diethoxy ethyl peroxy dicarbonate, diethoxyhexyl peroxy dicarbonate, , Bis (3-methoxy-3-methoxybutyl) peroxy dicarbonate, dibutyl peroxy dicarbonate, dicetyl peroxy dicarbonate, dimyristyl peroxy dicarbonate, 1,1 , 3,3-tetramethylbutyl peroxypivalate, hexyl peroxypivalate, butyl peroxypivalate, trimethylhexanoyl peroxide, dimethylhydroxybutyl peroxy Amyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, amyl peroxy pivalate, t-butyl peroxy pivalate, t-amyl peroxide, Organic peroxides such as peroxy-2-ethylhexanoate, lauryl peroxide, dilauroyl peroxide, didecanoyl peroxide, benzoyl peroxide or dibenzoyl peroxide, Examples of the system compound include, but are not limited to, a mixture of a peroxide compound and a reducing agent in combination. In the present application, one kind or a mixture of two or more kinds of azo type, peroxide type or redox type compound as described above can be used.

The initiator is contained in an amount of 0.01 to 5 parts by weight, specifically 0.05 to 3 parts by weight, more specifically 0.1 to 1 part by weight, based on 100 parts by weight of the total of the monomer mixture constituting the (meth) acrylic copolymer . In the above range, the curing reaction can be completely carried out, and the remaining amount of the initiator remains, the permeability can be prevented from being lowered, the bubble generation can be lowered, and the reactivity can be improved.

The silane coupling agent can be made to have high reliability because it does not have bubbles or exfoliation even after repetitive bending at high temperature and high humidity at a predetermined radius of curvature after attaching the adhesive film to the adherend. In addition, the silane coupling agent can lower the peeling strength reduction ratio of the formula (1) by increasing the peeling strength even after the adhesive film is allowed to stand at high temperature and high humidity for a predetermined time.

The silane coupling agent may be an epoxy group-containing silane coupling agent. Epoxy group-containing silane coupling agents include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) Ethyl trimethoxysilane. &Lt; / RTI &gt; Specifically, the epoxy group-containing silane coupling agent having a glycidoxidation period includes 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane . The silane coupling agent may be contained in an amount of 0.01 to 0.10 parts by weight, specifically 0.05 to 0.10 parts by weight based on 100 parts by weight of the total of the monomer mixture constituting the (meth) acrylic copolymer. In the above range, reliability can be secured in the bending state at the high temperature and high humidity described above, and not only the peel strength is high even at a high temperature, but also the modulus difference between low temperature, normal temperature and high temperature can be low.

The pressure-sensitive adhesive composition may further include a crosslinking agent. The cross-linking agent can increase the degree of crosslinking of the pressure-sensitive adhesive composition and increase the mechanical strength of the pressure-sensitive adhesive film. The crosslinking agent may comprise a multifunctional (meth) acrylate capable of curing with an active energy beam. In an embodiment, the crosslinking agent is selected from the group consisting of 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (Meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified di (meth) acrylate, di (Meth) acrylate, trimethylolpropane di (meth) acrylate, acryloyloxyethyl isocyanurate, allyl cyclohexyl di (meth) acrylate, tricyclodecane dimethanol Di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, neopentyl glycol modified trimethylpropane di (meth) acrylate, adamantane di (meth) Bifunctional acrylates such as 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene and the like; (Meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide Trifunctional acrylates such as modified trimethylolpropane tri (meth) acrylate, trifunctional urethane (meth) acrylate or tris (meth) acryloxyethylisocyanurate; Tetrafunctional acrylates such as diglycerin tetra (meth) acrylate or pentaerythritol tetra (meth) acrylate; Pentafunctional acrylates such as dipentaerythritol penta (meth) acrylate; (Meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate or urethane (meth) acrylate (ex. Isocyanate monomer and trimethylol propane tri (Meth) acrylates of polyhydric alcohols can be used as the crosslinking agent. The polyfunctional (meth) acrylates of polyhydric alcohols may be used alone or in combination of two or more. . The crosslinking agent is contained in an amount of 0.01 to 10 parts by weight, specifically 0.03 to 7 parts by weight, specifically 0.1 to 5 parts by weight, based on 100 parts by weight of the total of the monomer mixture constituting the (meth) acrylic copolymer There is an effect of excellent adhesion and reliability in the above range.

The pressure-sensitive adhesive composition may optionally contain a curing accelerator, an ionic liquid, a lithium salt, an inorganic filler, a softener, a molecular weight modifier, an antioxidant, an antioxidant, a stabilizer, a tackifier resin, a modifying resin (polyol resin, phenol resin, (Coloring pigments, extender pigments, etc.), treating agents, ultraviolet light blocking agents, fluorescent whitening agents, dispersing agents, heat stabilizers, antioxidants, antioxidants, A light stabilizer, an ultraviolet absorber, an antistatic agent, a coagulant, a lubricant and a solvent.

The pressure-sensitive adhesive composition may have a viscosity at 25 ° C ranging from 300 cPs to 50,000 cPs, and may have an effect of obtaining excellent coating and thickness uniformity in the above range.

The pressure-sensitive adhesive composition can be produced by partially polymerizing a monomer mixture for a (meth) acrylic copolymer having a hydroxyl group as an initiator, and further comprising an initiator and a silane coupling agent. Mentioned cross-linking agent, additives, and the like. Alternatively, the pressure-sensitive adhesive composition may be prepared by partially polymerizing a mixture comprising a monomer mixture, a initiator and a silane coupling agent for a (meth) acrylic copolymer having a hydroxyl group, and further containing an initiator. Mentioned cross-linking agent, additives, and the like. Partial polymerization may include solution polymerization, suspension polymerization, photopolymerization, bulk polymerization, or emulsion polymerization. Specifically, the solution polymerization can be carried out at 50 DEG C to 100 DEG C by adding an initiator to the monomer mixture. As the initiator, a photopolymerization initiator such as acetophenone-based and 1-hydroxycyclohexyl phenyl ketone including 2,2-dimethoxy-2-phenylacetophenone and the like can be used. Partial polymerization can be carried out at 25 DEG C with a viscosity of from 1,000 cPs to 10,000 cPs, specifically from 4,000 cPs to 9,000 cPs. The adhesive film can be produced by a conventional method. For example, the pressure-sensitive adhesive composition may be coated on a release film and cured. Curing may include irradiation of the irradiation dose 400mJ / cm ² to 3000mJ / cm ² at a wavelength of 300nm to 400nm into a low-pressure lamp in an oxygen-free state.

Hereinafter, an adhesive film according to another embodiment of the present invention will be described.

The adhesive film according to this embodiment may include a (meth) acrylic copolymer having a hydroxyl group, an initiator, a silane coupling agent, and organic nanoparticles. By further including the organic nanoparticles, it is possible to further increase the modulus of the adhesive film at high temperature, thereby preventing the peeling and / or lifting and / or bubble generation at high temperature of the adhesive film, thereby further improving reliability at high temperatures. The organic nanoparticles have a high glass transition temperature and can increase the modulus of the adhesive film at high temperatures. Organic nanoparticles are described in detail below. Specifically, the pressure-sensitive adhesive film may have a modulus of 20 kPa to 500 kPa, specifically 20 kPa to 100 kPa at 80 ° C. Within this range, high temperature reliability improvement effects can be obtained. The pressure-sensitive adhesive film may have a modulus of 25 kPa to 500 kPa, specifically 30 kPa to 100 kPa at 25 ° C. Within the above range, productivity improvement effect may be obtained. The pressure-sensitive adhesive film may have a modulus of 30 kPa to 500 kPa, specifically 10 kPa to 300 kPa, more specifically 20 kPa to 150 kPa at -20 ° C. Within the above-mentioned range, viscoelastic characteristics are exhibited at a low temperature and the recovery power is excellent. The pressure-sensitive adhesive film showing good folding property at low temperature can have good folding property even at room temperature and high temperature. The modulus of the adhesive film at 80 ° C at a modulus of -20 ° C may be 1: 1 to 1:10, specifically 1: 1 to 1: 8, more specifically 1: 1 to 1: 5 . In the above-mentioned range, the adhesive film does not deteriorate the adhesive force between the adherend in a wide temperature range (-20 캜 to 80 캜) and can be used for a flexible optical member.

The organic nanoparticles have a high modulus of the adhesive film at high temperature, good foldability at normal temperature and high temperature of the adhesive film, excellent low temperature and / or room temperature viscoelasticity of the adhesive film, The high-temperature viscoelasticity of the resin is stably expressed. Further, by applying nanoparticles having a specific average particle diameter and reducing the difference in refractive index between the nanoparticles and the (meth) acrylic copolymer having a hydroxyl group, the adhesive film can have excellent transparency despite containing organic nanoparticles.

The organic nanoparticles may have an average particle diameter of 10 nm to 400 nm, specifically 10 nm to 300 nm, more specifically 10 nm to 200 nm, more specifically 50 nm to 150 nm. Within this range, it is possible to prevent the organic nanoparticles from being clumped, do not affect the folding of the adhesive film, and the transparency of the adhesive film may be good even within the range of difference in refractive index as described below.

The refractive index difference between the organic nanoparticles and the (meth) acrylic copolymer having a hydroxyl group may be 0.1 or less, specifically 0 or more and 0.05 or less, specifically 0 or more and 0.02 or less. In the above range, the transparency of the adhesive film can be excellent. The refractive index of the organic nanoparticles may be 1.40 to 1.70, specifically 1.45 to 1.60. Within the above range, the transparency of the adhesive film may be excellent.

The organic nanoparticles may be core-shell type organic nanoparticles, and the core and shell may satisfy the following formula 3: that is, the core and the shell may both be organic nanoparticles. When such a particle type is used, the adhesive property of the adhesive film is good, and the balance property of elasticity and flexibility can be effective.

<Formula 3>

Tg (c) < Tg (s)

(Unit: 占 폚), and Tg (s) is the glass transition temperature (unit: 占 폚) of the shell.

As used herein, the term " shell " means the outermost layer of the organic nanoparticles. The core may be a single spherical particle. However, the core may further comprise additional layers surrounding the spherical particles if they have the above glass transition temperature.

Specifically, the glass transition temperature of the core may be -150 ° C to 10 ° C, specifically -150 ° C to -5 ° C, more specifically -150 ° C to -20 ° C. Within this range, there may be a low temperature and / or room temperature viscoelastic effect of the adhesive film. The core may include at least one of polyalkyl (meth) acrylate or polysiloxane having the above glass transition temperature.

The polyalkyl (meth) acrylate may be at least one selected from the group consisting of polymethyl acrylate, polyethylacrylate, polypropyl acrylate, polybutyl acrylate, polyisopropyl acrylate, polyhexyl acrylate, polyhexyl methacrylate, polyethylhexyl acrylate And polyethylhexyl methacrylate, polysiloxane, and is not necessarily limited thereto.

The polysiloxane can be, for example, an organosiloxane (co) polymer. The organosiloxane (co) polymer may be one which is not cross-linked, or a cross-linked (co) polymer may be used. In order to impart impact resistance and colorability, an organosiloxane (co) polymer in a crosslinked state can be used. It is a crosslinked form of organosiloxane, specifically crosslinked dimethylsiloxane, methylphenylsiloxane, diphenylsiloxane or a mixture of two or more thereof. By using a copolymerized form of two or more organosiloxanes, the refractive index can be adjusted from 1.41 to 1.50.

The crosslinking state of the organosiloxane (co) polymer can be determined by the degree of dissolution by various organic solvents. As the crosslinking state deepens, the degree of dissolution by the solvent becomes smaller. As the solvent for determining the crosslinking state, acetone, toluene and the like can be used. Specifically, the organosiloxane (co) polymer may have a portion which is not dissolved by acetone or toluene. The insoluble matter to the toluene of the organosiloxane copolymer may be 30% or more.

Additionally, the organosiloxane (co) polymer may further comprise an alkyl acrylate crosspolymer. The alkyl acrylate crosslinked polymer may be selected from the group consisting of methyl acrylate, ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. For example, n-butyl acrylate or 2-ethylhexyl acrylate having a low glass transition temperature may be used.

Specifically, the glass transition temperature of the shell may be from 15 캜 to 150 캜, specifically from 35 캜 to 150 캜, more specifically from 50 캜 to 140 캜. In the above range, the dispersibility of the organic nanoparticles in the (meth) acrylic copolymer may be excellent. The shell may comprise a polyalkyl methacrylate having said glass transition temperature. For example, it is possible to use polymethylmethacrylate (PMMA), polyethylmethacrylate, polypropylmethacrylate, polybutylmethacrylate, polyisopropylmethacrylate, polyisobutylmethacrylate and polycyclohexylmethacrylate Rate, &lt; / RTI &gt; but is not necessarily limited thereto.

The core may comprise from 30 wt% to 99 wt%, specifically from 40 wt% to 95 wt%, and more specifically from 50 wt% to 90 wt%, of the organic nanoparticles. Within the above range, the folding property of the pressure-sensitive adhesive film may be good in a wide temperature range. The shell may comprise from 1 wt% to 70 wt%, specifically from 5 wt% to 60 wt%, more specifically from 10 wt% to 50 wt%, of the organic nanoparticles. Within the above range, the folding property of the pressure-sensitive adhesive film may be good in a wide temperature range.

The organic nanoparticles are contained in an amount of 0.1 to 20 parts by weight, specifically 0.5 to 10 parts by weight, specifically 0.5 to 5 parts by weight, more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the total of the monomer mixture and the organic nanoparticles constituting the (meth) By weight. Within this range, the viscoelasticity and modulus of the pressure-sensitive adhesive film can be balanced.

The initiator, the silane coupling agent, and the cross-linking agent may be included in the above-described amounts in the range of the above-described amounts of the monomer mixture constituting the (meth) acrylic copolymer having a hydroxyl group and the total of the total organic nanoparticles of 100 parts by weight, .

The organic nanoparticles can be produced by a conventional emulsion polymerization method.

The optical member according to an embodiment of the present invention includes an optical film and an adhesive film formed on at least one side of the optical film, and the adhesive film may include an adhesive film according to embodiments of the present invention. Thus, the optical member has good bending and / or good folding properties and can be used in a flexible display device.

The optical film may be a polarizing plate, a color filter, a retardation film, an elliptically polarizing film, a reflective film, an antireflection film, a compensation film, a brightness enhancement film, an orientation film, a light diffusion film, indium tin oxide) film, and the like. The method for producing an optical film can be easily manufactured by a person having ordinary skill in the art to which the present invention belongs.

For example, the touch panel can be formed by attaching the touch pad to a window or an optical film using an adhesive film. Or may be applied to an ordinary polarizing film as an adhesive film as in the prior art.

The optical display device of the present invention may include the pressure-sensitive adhesive film of the present invention. The optical display device may include an organic light emitting diode display, a liquid crystal display, and the like. The optical display device may include a flexible display device. However, the optical display device may include a non-flexible display device.

Hereinafter, a flexible display device according to an embodiment of the present invention will be described with reference to FIG. 1 is a cross-sectional view of a flexible display device according to an embodiment of the present invention.

1, a flexible display device 100 according to an exemplary embodiment of the present invention includes a display unit 110, an adhesive layer 120, a polarizer 130, a touch screen panel 140, and a flexible window film 150, and the adhesive layer 120 may include an adhesive film according to an embodiment of the present invention.

The display unit 110 is for driving the flexible display device 100 and may include an optical element including an OLED, an LED, or an LCD device formed on a substrate and a substrate. Although not shown in FIG. 1, the display unit 110 may include a lower substrate, a thin film transistor, an organic light emitting diode, a planarization layer, a protective layer, and an insulating layer.

The polarizing plate 130 may implement polarizing of the inner light or prevent reflection of the external light to realize the display or increase the contrast ratio of the display. The polarizing plate may be composed of a polarizer alone. Or the polarizing plate may include a polarizing film and a protective film formed on one or both sides of the polarizing film. Or the polarizing plate may include a polarizer and a protective coating layer formed on one or both sides of the polarizer. The polarizer, the protective film, and the protective coating layer may be conventional ones known to those skilled in the art.

The touch screen panel 140 senses a change in capacitance caused when a conductor such as a human body or a stylus touches, and generates an electrical signal. The display unit 110 can be driven by this signal. The touch screen panel 140 may include a first sensor electrode and a second sensor electrode formed between the first sensor electrode and the first sensor electrode, which are formed by patterning a conductive conductive material. have. The conductors for the touch screen panel 340 may include, but are not limited to, metal nanowires, conductive polymers, carbon nanotubes, and the like.

1 illustrates a polarizing plate 130 and a touch screen panel 140 stacked by an adhesive film or an adhesive film or a polarizer or a polarizing plate on a touch screen panel 140 to form a polarizing plate 130 and a touch screen panel 140. [ 140 may be integrated.

The flexible window film 150 may be formed at the outermost portion of the flexible display device 300 to protect the display device.

Although not shown in FIG. 1, the pressure sensitive adhesive film of the present invention is further formed between the polarizer 130 and the touch screen panel 140 and / or between the touch screen panel 140 and the flexible window film 150, Screen panel, and flexible window film.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It should be understood, however, that the same is by way of illustration and example only and is not to be construed in any way as limiting the invention.

Manufacturing example

Organic nanoparticles were prepared by emulsion polymerization. The core is polybutyl acrylate, the shell is polymethyl methacrylate, the shell is 35 weight% of the organic nanoparticles, the core is 65 weight% of the organic nanoparticles, the average particle diameter is 100 nm and the refractive index is 1.48 .

Example  One

100 parts by weight of a monomer mixture comprising 70 parts by weight of 2-ethylhexyl acrylate (2-EHA) and 30 parts by weight of 4-hydroxybutyl acrylate (4-HBA), 100 parts by weight of Irgacure 651 (2,2-dimethoxy- - phenylacetophenone, BASF) and 0.05 part by weight of 3-glycidoxypropyltrimethoxysilane (KBM-403) as a silane coupling agent were well mixed in a reactor. The dissolved oxygen in the reactor was replaced with a nitrogen gas and irradiated with ultraviolet light for a few minutes using a low pressure mercury lamp to partially polymerize the monomer mixture to prepare a viscous liquid having a viscosity of 5,000 cps at 25 ° C. 0.5 part by weight of Irgacure 184 (1-hydroxycyclohexyl phenyl ketone, BASF) was added to the viscous liquid and mixed to prepare a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition was applied to a PET (polyethylene terephthalate) film as a release film, and irradiated with ultraviolet light at a dose of 2000 mJ / cm ² to produce a pressure-sensitive adhesive sheet of 50 탆 thick adhesive film and PET film.

Example  2

, 100 parts by weight of a mixture containing 74 parts by weight of 2-ethylhexyl acrylate (2-EHA), 23 parts by weight of 4-hydroxybutyl acrylate (4-HBA) and 3 parts by weight of the organic nanoparticles of Production Example, Irgacure 651 0.03 part by weight of 2,2-dimethoxy-2-phenylacetophenone, BASF) and 0.05 part by weight of 3-glycidoxypropyltrimethoxysilane (KBM-403) as a silane coupling agent were well mixed in a reactor. The dissolved oxygen in the reactor was replaced with a nitrogen gas and irradiated with ultraviolet light for a few minutes using a low pressure mercury lamp to partially polymerize the monomer mixture to prepare a viscous liquid having a viscosity of 5,000 cps at 25 ° C. 0.5 part by weight of Irgacure 184 (1-hydroxycyclohexyl phenyl ketone, BASF) was added to the viscous liquid and mixed to prepare a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition was applied to a PET (polyethylene terephthalate) film as a release film, and irradiated with ultraviolet light at a dose of 2000 mJ / cm ² to produce a pressure-sensitive adhesive sheet of 50 탆 thick adhesive film and PET film.

Example  3 to Example  7

A pressure-sensitive adhesive sheet of 50 탆 thick adhesive film and PET film was prepared in the same manner as in Example 2, except that the composition of the pressure-sensitive adhesive composition was changed as shown in Table 1 below.

Comparative Example  One

A pressure-sensitive adhesive sheet of a pressure-sensitive adhesive film and a PET film having a thickness of 50 탆 was prepared in the same manner as in Example 1, except that the composition of the pressure-sensitive adhesive composition was changed as shown in Table 1 below.

Comparative Example  2

A pressure-sensitive adhesive sheet of 50 탆 thick adhesive film and PET film was prepared in the same manner as in Example 2, except that the composition of the pressure-sensitive adhesive composition was changed as shown in Table 1 below.

The properties of the pressure-sensitive adhesive sheets prepared in Examples and Comparative Examples were evaluated in the following Table 1, and the results are shown in Table 1 below.

 (1) High-temperature and high-humidity reliability: A pressure-sensitive adhesive film was obtained from the pressure-sensitive adhesive sheets of Examples and Comparative Examples, and a pressure-sensitive adhesive film was obtained in the order of PET film (thickness: 75 탆) / adhesive film (thickness: 50 탆) / PET film Laminated, adhered with a roller, aged at room temperature for 12 hours, and cut into a size of width x length (70 mm x 25 mm) to prepare a specimen. At this time, the PET film was subjected to corona treatment, and then the adhesive film and the corona-treated surface were adhered to each other. The prepared specimen was fixed to a flexural evaluation equipment (CFT-2000, manufactured by Covotech) using an adhesive (4965, Tesa). In this case, the lateral direction of the specimen was bent, and the bending radius was 3 mm. After storage for 3 days at 60 ° C and 93% relative humidity, the bubble formation in the adhesive film and the separation of the adhesive film from the PET film were evaluated. It is very good when there is no peeling or bubble, and when there is no damage to the PET film, there is no peeling or bubble, but if there is fine damage to the PET film, good, peeling, bubble or breakage of the PET film is evaluated as bad.

(2) Peel strength: A PET film having a thickness of 75 占 퐉 was laminated on one side of an adhesive film of the pressure sensitive adhesive sheets of Examples and Comparative Examples, and a PET film (thickness: 75 占 퐉) / an adhesive film (thickness: 50 占 퐉) / PET film Thickness: 75 mu m) was obtained. A corona processor was used to treat one side of a PET film with a width x length x thickness (150 mm x 25 mm x 75 μm) and treated with a corona twice (total dose: 156 dose) while discharging the plasma with a dose of 78 dose. After the PET film (thickness: 75 mu m) was removed from the laminate, the corona-treated side of the PET film was laminated and cut to a width x length (150 mm x 25 mm) , A glass plate was laminated and lapped with a 2 kg roller to prepare a specimen.

The specimen was allowed to stand at 25 DEG C for 30 minutes, and the peel strength (A) was measured by pulling the PET film at 25 DEG C at a rate of 300 mm / min using a TA.XT_Plus Texture Analyzer (Stable Micro System).

The specimens were allowed to stand at 60 DEG C and 93% relative humidity for 3 days, and then the PET film was pulled at a rate of 300 mm / min at 25 DEG C using a TA.XT_Plus Texture Analyzer (Stable Micro System) (B) was measured.

(3) Difference in Peel Strength Reduction Rate and Peel Strength: The peel strength obtained in (2) was used to calculate according to Equation 1 and Equation 2 above.

(4) Modulus (G '): The viscoelasticity was measured at a shear rate of 1 rad / sec using a Rheometer (Anton Paar MCR-501) as a dynamic viscoelasticity measuring device under an auto strain condition at a strain of 1%. After removing the release film from the pressure-sensitive adhesive sheet, a plurality of pressure-sensitive adhesive films each having a thickness of 50 占 퐉 were laminated, laminated to a thickness of 500 占 퐉, and the laminate was perforated with a perforator having a diameter of 8 mm. Using a jig of 8 mm, the specimens were subjected to a measurement at a temperature rising rate of 5 DEG C / min in a temperature range of -60 DEG C to 90 DEG C under a load of 300 gf, and were measured at 80 DEG C, 25 DEG C and -20 DEG C Modulus was obtained.

(5) Glass transition temperature: The glass transition temperature of the pressure-sensitive adhesive films was measured using differential scanning calorimetry (DSC) on the pressure-sensitive adhesive films of Examples and Comparative Examples.

(6) Haze: Haze meter (Nippon Denshoku Model NDH 5000) equipment was used for the adhesive films of Examples and Comparative Examples. The haze was measured for an adhesive film having a thickness of 50 탆 according to ASTM D 1003-95 5 (" Standard Test for Haze and Luminous Transmittance of Transparent Plastic ").

(7) Folding evaluation: A PET film (thickness: 50 탆) / an adhesive film (thickness: 100 탆) / a PET film (thickness: 50 탆) were laminated in this order and adhered with a roller. (70 mm x 140 mm), and the prepared specimens were fixed to a flexural evaluation apparatus (CFT-2000, manufactured by Covotech) using an adhesive (4965, Tesa). At this time, the PET film was subjected to corona treatment, and then the adhesive film and the corona-treated surface were adhered to each other. Bending the specimen in the longitudinal direction at 60 ° C and 93% relative humidity, bending the specimen at a radius of curvature of 3 mm, 30 cycles per minute, wherein one cycle means bending and spreading the specimen at the radius of curvature, bending and holding for 1 second And 100,000 cycles of bending under the post-stretching condition. X when peeling or bubbling occurred after 100,000 cycles, and when the peeling and bubbling did not occur, it was indicated with.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 Comparative Example 2 2-EHA ¹
(Parts by weight) 70 74 77 77 80 70 60 85 57 n-BA ²
(Parts by weight) - - - - - 10 20 - - 4-HBA ³
(Parts by weight 30 23 20 20 17 - - 15 20 2-HEA ⁴
(Parts by weight) - - - - - 17 17 - - IBOA ⁵
(Parts by weight) - - - - - - - - 20 Organic nanoparticles
(Parts by weight) - 3 3 3 3 3 3 - 3 Initiator Irgacure 184
(Parts by weight) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Silane coupling agent
(Parts by weight) 0.05 0.05 0.05 0.10 0.05 0.05 0.05 - - High temperature and high reliability Good Extremely
Good Good Extremely
Good Good Extremely
Good Extremely
Good Bad Bad Peel strength @ 25 ℃
(A, gf / in) 1670 1437 1263 1263 1025 2258 2587 1259 3450 Peel strength @ 60 ° C and relative humidity 93%
(B, gf / in) 1587 1385 1211 1216 988 2170 2535 216 3280 Difference in peel strength
(gf / in) 88 52 52 47 37 88 52 1043 170 Peel strength reduction ratio (%) 5.23 3.62 4.12 3.72 3.60 3.90 2.01 82.84 4.93 Modulus
(kPa) @ 80 DEG C 28 24 22 22 20 31 34 15 49 Modulus
(kPa) @ 25 DEG C 41 36 34 34 32 43 47 27 65 Modulus
(kPa)
@ -20 ℃ 112 98 91 91 85 93 105 70 7120 Glass transition temperature (캜) -56.7 -57.8 -59.4 -59.4 -60.5 -51.3 -48.0 -62.3 -24.8 Haze (%) 0.48 0.69 0.69 0.54 0.50 0.61 0.64 0.79 0.88 Folding evaluation ○ ○ ○ ○ ○ ○ ○ × ×

2-ethylhexyl acrylate, 2-HEA: 2-hydroxyethyl acrylate, 4-HBA: 4-hydroxybutyl acrylate, n-BA: n-butyl acrylate, IBOA: Nyl acrylate

As shown in Table 1, the adhesive film of this example had good reliability even in the bending state at high temperature and high humidity, and the reduction ratio of peel strength to room temperature was low at high temperature and high humidity. In addition, the pressure-sensitive adhesive film of the present embodiment including the organic nanoparticles has a high modulus at a high temperature, thereby further improving reliability at a high temperature.

On the other hand, in the case of the pressure-sensitive adhesive film of Comparative Example 2, the folding reliability was lowered because the Tg of the pressure-sensitive adhesive film was too high even if the reduction ratio of the peel strength to the room temperature was low at high temperature and high humidity.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (15)

(Meth) acrylic copolymer having a hydroxyl group, an initiator and a silane coupling agent,
Wherein the reduction ratio of the peel strength in the following formula (1) is 10% or less,
<Formula 1>
Reduction ratio of peel strength = | B - A | / A x 100
(In the above formula 1, for the specimen in which the glass plate, the adhesive film, and the PET film are sequentially laminated, A indicates that the specimen is left at 25 DEG C for 30 minutes and then the PET film is peeled from the pressure- The peel strength when peeled off at a speed of 300 mm / min. B: The test piece was allowed to stand at 60 占 폚 and 93% relative humidity for 3 days, and then the PET film was peeled from the adhesive film at a peeling speed of 300 mm / min ,
The (meth) acrylic copolymer having a hydroxyl group is a copolymer of a monomer mixture containing 5 to 30% by weight of a hydroxyl group-containing (meth) acrylate and 70 to 95% by weight of an alkyl group-containing (meth) acrylate,
Wherein the pressure-sensitive adhesive film has a modulus at a modulus of -20 DEG C at 80 DEG C of 1: 1 to 1:10.
The adhesive film according to claim 1, wherein B - A in the formula (1) is 200 gf / in or less.
The pressure-sensitive adhesive film according to claim 1, wherein B in the formula (1) is 900 gf / in or more.
The adhesive film according to claim 1, wherein the pressure-sensitive adhesive film has a modulus of 20 kPa to 500 kPa at 80 캜.
The pressure-sensitive adhesive film according to claim 1, wherein the pressure-sensitive adhesive film has a modulus of 20 kPa to 500 kPa at -20 캜.
delete The pressure-sensitive adhesive film according to claim 1, wherein the pressure-sensitive adhesive film is a pressure-sensitive adhesive film (thickness: 100 탆) adhered between two corona treated PET substrates having a thickness of 50 탆 and has a curvature radius of 3 mm Wherein the number of cycles during which the film is stretched or bubbled is not less than 100,000 cycles when bending (one cycle of bending and spreading the adhesive film once in half) at a rate of 30 cycles per minute is repeated, .
The adhesive film according to claim 1, wherein the silane coupling agent comprises a silane coupling agent having an epoxy group.
delete The method of claim 1, wherein the adhesive film further comprises organic nanoparticles,
Wherein the organic nanoparticles have an average particle diameter of 10 nm to 400 nm.
11. The method of claim 10, wherein the organic nanoparticles are core-
Wherein the core and the shell satisfy the following formula 3:
<Formula 3>
Tg (c) < Tg (s)
(Unit: 占 폚), and Tg (s) is the glass transition temperature (unit: 占 폚) of the shell.
[Claim 10] The method of claim 10, wherein the organic nanoparticles are included in the monomer mixture for the (meth) acrylic copolymer having the hydroxyl group in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the total of the organic nanoparticles. film.
The pressure-sensitive adhesive film according to claim 10, wherein the pressure-sensitive adhesive film has a haze of 1% or less at a wavelength of 380 nm to 780 nm.
An optical film, and an adhesive film formed on at least one side of the optical film,
Wherein the adhesive film comprises the adhesive film of any one of claims 1 to 5, 7, 8, 10 to 13.
An optical display device comprising the optical member of claim 14.

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