KR101845137B1

KR101845137B1 - Adhesive film, optical member comprising the same and optical display apparatus comprising the same

Info

Publication number: KR101845137B1
Application number: KR1020150151380A
Authority: KR
Inventors: 강지원; 김지호; 김용태; 김일진; 김지희; 이진영; 한재현
Original assignee: 삼성에스디아이 주식회사; 삼성전자주식회사
Priority date: 2015-10-29
Filing date: 2015-10-29
Publication date: 2018-04-04
Also published as: KR20170051620A

Abstract

(Meth) acrylic copolymer and organic nanoparticles having a hydroxyl group, an alkyl group and an amide group, wherein the rate of change of the peel strength of formula (1) is 0.5 or less and the peel strength at 60 ° C is 700 gf / An optical member including the same, and an optical display device including the optical member.

Description

TECHNICAL FIELD [0001] The present invention relates to an adhesive film, an optical member including the adhesive member, and an optical display device including the adhesive member. [0002]

The present invention relates to an adhesive film, an optical member including the same, 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. A touch pad has a structure in which a transparent clear adhesive (OCA) is laminated between a window film and a conductive film. The transparent adhesive film may be laminated between two kinds of window films, conductive films, touch screen panels, polarizing plates, and organic light emitting devices.

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 large difference in peel strength between a high temperature and a normal temperature may deteriorate the reliability of the optical display device.

On the other hand, a flexible display device capable of being folded and unfolded has been developed. The flexible display device must have good foldability of various optical elements included in the apparatus. The adhesive film should also have good folding properties. In order for the adhesive film to have good foldability, the modulus at low temperature must also be low. If the modulus of low temperature is high, lifting and peeling occur when folding, and folding becomes difficult due to stress due to folding.

However, when the peel strength of the adhesive film at room temperature and high temperature is increased, the adhesive film having a high modulus at high temperature can improve the reliability of the optical display device at high temperature, but the modulus at low temperature can be increased, . In addition, when the high temperature modulus is low, the durability is poor, and bubbles may be generated or lifted at high temperature / high humidity conditions.

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 which can minimize the difference in peel strength between room temperature and high temperature.

Another problem to be solved by the present invention is to provide a pressure-sensitive adhesive film having good foldability.

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

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 and an organic nanoparticle having a hydroxyl group, an alkyl group and an amide group, and the organic nanoparticle, wherein the rate of change of the peel strength in the following formula (1) is 0.5 or less and the peel strength is 700 gf / in Can be more than:

&Lt; Formula 1 > Change rate of peel strength = | A-B | / A

(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 a pressure-sensitive adhesive film capable of minimizing a difference in peel strength between room temperature and high temperature.

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

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

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.
2 is a conceptual diagram of a specimen for peel strength measurement.

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 present specification, the "peel strength" of a pressure-sensitive adhesive film was measured by using a corona processor to treat a PET (polyethylene terephthalate) film of width x length x thickness (150 mm x 25 mm x 75 m) : 156 dose). The corona-treated side of the PET film was laminated on both sides of the adhesive film to prepare the test piece shown in Fig. 2 (a). The specimen was autoclaved at a pressure of 3.5 bar at 50 ° C for 1000 seconds and the specimens were fixed on a TA.XT_Plus Texture Analyzer (Stable Micro System). Referring to FIG. 2 (b), when one PET film is fixed at 25 ° C. and 60 ° C. in the TA.XT_Plus Texture Analyzer, and the other PET film is pulled at a speed of 50 mm / min, the PET film starts to peel The peeling strength at the time point of the peeling strength was measured.

In the present specification, the "modulus" of the pressure-sensitive adhesive film 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 탆 and a diameter of 8 mm, strain was measured at a temperature rising rate of 5 ° C / min in a temperature range of -60 ° C to 90 ° C using an 8 mm jig under an auto strain condition at a strain of 1%, and the modulus was measured at -20 ° C and 80 ° C, 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 the folding measurement temperature (for example, -20 ° C), bending the specimen at a radius of curvature of 3 mm, and bending at 30 cycles per minute, wherein one cycle means bending and spreading the specimen at the radius of curvature, Means a condition of bending 100,000 cycles under the condition of maintaining and stretching for 1 second.

As used herein, "good foldability" means that no peeling or bubbling has occurred at the folding site when the folding condition is applied.

In the present specification, "low temperature" may mean -20 ° C, "normal temperature" means 25 ° C, and "high temperature" may mean 60 ° C to 85 ° C.

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

The adhesive film according to this embodiment (hereinafter, referred to as an 'adhesive film') may include a (meth) acrylic copolymer having an hydroxyl group, an alkyl group and an amide group, and organic nanoparticles.

By including the (meth) acrylic copolymer and the organic nanoparticles, the adhesive film minimizes the peel strength at room temperature and the peel strength at high temperature, thereby enhancing the reliability of the adhesive film at room temperature and high temperature. Specifically, in the pressure-sensitive adhesive film, the rate of change of the peel strength in the following formula (1) may be 0.5 or less, more specifically, 0.01 to 0.3: In the above range, even if the pressure-sensitive adhesive film is used in a display device, The reliability at high temperature and room temperature can be high. Further, the adhesive film has a high peeling strength even at a high temperature, so that lifting and / or peeling at a high temperature can be prevented. Particularly, when the rate of change of the peel strength is 0.05 to 0.2, the pressure-sensitive adhesive film can be excellent in folding property at room temperature and high temperature:

&Lt; Formula 1 > Change rate of peel strength = | A-B | / A

(In the above formula 1, A represents the peeling strength of the pressure-sensitive adhesive film at 25 ° C, and B represents the peeling strength of the pressure-sensitive adhesive film at 60 ° C).

The adhesive film may have a peel strength of at least 500 gf / in, specifically 500 gf / in to 5000 gf / in, more specifically 700 gf / in to 4000 gf / in at 25 ° C. The adhesive film may have a peel strength of at least 700 gf / in, specifically 700 gf / in to 5000 gf / in, more specifically 800 gf / in to 4000 gf / in at 60 ° C. Within this range, the pressure-sensitive adhesive film has good reliability even at a high temperature and can have a good folding property at a high temperature.

By including the organic nanoparticles, the adhesive film increases the modulus at a high temperature, thereby preventing the adhesive film from peeling and / or lifting and / or bubbling at a high temperature, thereby enhancing 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 100 KPa, specifically 25 kPa to 80 kPa at 80 ° C. Within this range, high temperature reliability can be enhanced.

Since the pressure-sensitive adhesive film contains the (meth) acrylic copolymer and the organic nanoparticles, the modulus at high temperature is increased, and the modulus difference at low temperature is small, so that the folding property can be excellent at both low temperature and high temperature. Specifically, the pressure-sensitive adhesive film may have a modulus ratio of 1.5 to 6, specifically 1.7 to 5.5 in the following formula 2: Within the above range, the modulus at low temperature is low, so that good folding property can be obtained and reliability can be improved at high temperature , The modulus change rate according to low temperature and high temperature is low, so that it is possible to minimize the deformation of the adherend due to excellent folding property despite the change of the temperature environment:

&Quot; (2) " modulus ratio = C / D

(C is the modulus of the pressure-sensitive adhesive film at -20 deg. C, and D is the modulus of the pressure-sensitive adhesive film at 80 deg.

The pressure-sensitive adhesive film may have a modulus of 100 kPa or less at 20 deg. C, specifically 10 kPa to 100 kPa, more specifically 20 kPa to 90 kPa. In the above range, it is possible to exhibit good folding property at a low temperature when used in a display device. 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 pressure-sensitive adhesive film may have a modulus of 20 kPa to 100 kPa, specifically 25 kPa to 80 kPa at 80 ° C. In the above range, when used in a flexible device at a low temperature, the pressure-sensitive adhesive film is flexible and is easily used for an optical member without whitening.

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 占 퐉 to 300 占 퐉, specifically, 20 占 퐉 to 150 占 퐉. In the above range, it can be used in an optical display device.

The pressure-sensitive adhesive film may be a (meth) acryl-based copolymer prepared by partially polymerizing a monomer mixture containing a hydroxyl group-containing (meth) acrylate, an alkyl group-containing (meth) acrylate and an amide group- And a pressure-sensitive adhesive composition comprising an initiator.

The monomer mixture may form a (meth) acrylic copolymer having a hydroxyl group, an alkyl group and an amide group. The (meth) acrylic copolymer having a hydroxyl group, an alkyl group and an amide group forms a matrix of a pressure-sensitive adhesive film and can exhibit adhesiveness. The (meth) acryl-based copolymer can increase the peeling strength at high temperature of the pressure-sensitive adhesive film, lower the modulus at low temperature together with the organic nanoparticles, and increase the modulus at high temperature.

The (meth) acrylic copolymer having a hydroxyl group, an alkyl group and an amide group may have a glass transition temperature (Tg) of -150 ° C to -13 ° C, specifically -100 ° C to -20 ° 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, an alkyl group and an amide 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 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 included in the monomer mixture in an amount of 55% by weight to 90% by weight, such as 70% by weight to 90% by weight, 70% by weight to 83% by weight and 70% by weight to 80% . The adhesive strength and endurance reliability of the adhesive film can be further improved in the above range.

The amide group-containing (meth) acrylate can increase the peeling strength at high temperature of the pressure-sensitive adhesive film. In particular, the amide group-containing (meth) acrylate can have higher modulus as well as peel strength at high temperatures when contained together with organic nanoparticles. 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 amide group-containing (meth) acrylate may be included in the monomer mixture in an amount of 0.1 wt% to 10 wt%, for example, 0.1 wt% to 8 wt%, 0.5 wt% to 5 wt%, and 1 wt% to 2.5 wt% have. The effect of increasing the peel strength at high temperature in the above range may be obtained.

In one embodiment, the monomer mixture comprises from 5% by weight to 40% by weight (meth) acrylate of a hydroxyl group-containing (meth) acrylate in the total sum of hydroxyl group containing (meth) acrylate, alkyl group containing (meth) (Meth) acrylate in an amount of from 15 to 25% by weight, an alkyl group containing (meth) acrylate in an amount of from 55 to 90% by weight, specifically from 70 to 80% by weight, an amide group-containing (meth) Specifically 0.5% to 5% by weight. Within this range, an excellent effect of folding at high temperature may be obtained.

The monomer mixture may further include a copolymerizable monomer having no hydroxyl group, alkyl group or amide group. The copolymerizable monomer may be a monomer having ethylene oxide, a monomer having propylene oxide, a monomer having amine group, a monomer having alkoxy group, a monomer having phosphate group, a monomer having sulfonic acid group, a monomer having phenyl group, a monomer having silane group, And may include one or more of the monomers.

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 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.

The monomer mixture may further comprise a macromonomer.

The macromonomer has a functional group curable by an active energy ray and can be polymerized with a hydroxyl group-containing (meth) acrylate, an alkyl group-containing (meth) acrylate and / or amide group-containing (meth) acrylate. Specifically, the macromonomer may be represented by the following formula (1): < EMI ID =

&Lt; Formula 1 >

(In Formula 1, R ¹ is hydrogen or a methyl group, X represents a single bond or a divalent coupler, Y is methyl (meth) acrylate, ethyl (meth) acrylate, n- butyl (meth) acrylate, iso- butyl (Meth) acrylate, t-butyl (meth) acrylate, styrene, and (meth) acrylonitrile.

2 the coupler is an arylene group, -NR a C1 to C10 alkyl groups, C7 to C13 aryl alkyl group, C6 to C12 ² - (wherein, R ² is an alkyl group of hydrogen, or a C1 to C5), COO-, - _{O-, -S-, -SO 2 NH-,} -NHSO 2 -, may be a group derived from -NHCOO-, -OCONH, or heterocyclic.

The macromonomer may have a number average molecular weight of 2,000 to 20,000, specifically 2,000 to 10,000, more specifically 4,000 to 8,000. Within the above range, sufficient adhesive strength can be obtained, heat resistance is excellent, and deterioration of workability due to an increase in viscosity of the pressure-sensitive adhesive composition can be suppressed.

The macromonomer may have a glass transition temperature of from 40 캜 to 150 캜, specifically from 60 캜 to 140 캜, more specifically from 80 캜 to 130 캜. In the above range, the pressure-sensitive adhesive film can exhibit sufficient cohesive strength, and the degree of stickiness and deterioration of the adhesive force can be suppressed.

More specifically, the divalent linking group represented by X in the formula (1) may be represented by the following formulas (1a) to (1d):

&Lt; EMI ID =

&Lt; Formula 1c >

(In the above Chemical Formulas (1a) to (1d), * denotes the connecting site of the element)

Commercial macromonomers may be used. For example, a macromonomer having a methacryloyl group at the end and a segment corresponding to Y is methyl methacrylate, a macromonomer having a segment corresponding to Y as styrene, a macromonomer having a segment corresponding to Y as styrene / acrylonitrile And macromonomers in which the segment corresponding to Y is butyl acrylate.

The macromonomer may be included in the adhesive film in an amount of 0 to 20 wt%, for example, 0.1 to 20 wt%, 0.5 to 10 wt%, and 1 wt% to 5 wt%. Within the above range, the viscoelasticity of the pressure-sensitive adhesive film, the modulus and the recovery force can be balanced.

In one embodiment, the monomer mixture comprises from 5% to 40% of a hydroxyl group-containing (meth) acrylate in the total sum of hydroxyl group-containing (meth) acrylates, alkyl group containing (meth) acrylates, amide group containing (meth) (Meth) acrylate in an amount of from 15 wt% to 25 wt%, 55 wt% to 90 wt%, specifically 70 wt% to 83 wt% of an alkyl group-containing (meth) acrylate, 0.1 wt% to 10 wt% , Specifically 0.5% to 5% by weight of the macromonomer, and 0.1% to 20%, more specifically 0.5% to 10%, and more specifically 1% to 5% by weight of the macromonomer. Within this range, an excellent effect of folding at high temperature may be obtained.

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 size and reducing the difference in refractive index between the nanoparticles and the (meth) acrylic copolymer having a hydroxyl group, an alkyl group and an amide group, the adhesive film has excellent transparency despite containing organic nanoparticles Lt; / RTI >

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, aggregation of the organic nanoparticles can be prevented, the folding of the adhesive film is not affected, and the transparency of the adhesive film can be good.

The difference in refractive index between the organic nanoparticles and the (meth) acrylic copolymer having a hydroxyl group, an alkyl group and an amide 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 are core-shell type organic nanoparticles, and the core and the shell can satisfy the following formula 3: When the particle type as described above is used, the folding property of the pressure-sensitive adhesive film is good and it is effective for balance and physical properties of elasticity and flexibility Can be.

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, < / RTI > 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 can be produced by a conventional emulsion polymerization method.

The organic nanoparticles are added 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, based on 100 parts by weight of the total of the monomer mixture constituting the (meth) acrylic copolymer . Within this range, the viscoelasticity and modulus of the pressure-sensitive adhesive film can be balanced.

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. As the initiator, a photopolymerization initiator or a thermal polymerization initiator can be used.

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, 2-methoxy-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- (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- < / RTI > 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 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 Neopentylglycol adipate di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified di Acrylate, di (meth) acryloxyethyl isocyanurate, allyl cyclohexyl di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, dimethylol dicyclopentanedi (meth) Ethylene oxide modified hexahydrophthalic acid di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, neopentyl glycol modified trimethylpropane di (meth) acrylate, Bifunctional acrylates such as adamantane di (meth) acrylate or 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene; (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 may be 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 have. There is an effect of excellent adhesion and reliability in the above range.

The pressure-sensitive adhesive composition may further include a silane coupling agent. As the silane coupling agent, those conventionally known to those skilled in the art can be used. For example, there can be mentioned 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl tri A silicon compound having an epoxy structure such as methoxysilane; A polymerizable unsaturated group-containing silicon compound such as vinyltrimethoxysilane, vinyltriethoxysilane and (meth) acryloxypropyltrimethoxysilane; Containing silicon compounds such as 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane and N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane. ; And 3-chloropropyltrimethoxysilane, and the like, but are not limited thereto. Preferably, a silane coupling agent having an epoxy structure can be used. The silane coupling agent may be contained in an amount of 0.01 to 0.1 parts by weight, specifically 0.05 to 0.1 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 increasing the 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 may be prepared by partially polymerizing a monomer mixture for a (meth) acrylic copolymer having a hydroxyl group, an alkyl group and an amide group with an initiator, and then adding organic nanoparticles and an additional initiator. A crosslinking agent, a silane coupling agent, an additive, and the like may be further included. Alternatively, the pressure-sensitive adhesive composition may be prepared by partially polymerizing a mixture containing a monomer mixture, a nanoparticle and an initiator for a (meth) acrylic copolymer having a hydroxyl group, an alkyl group and an amide group, and further comprising an initiator. A crosslinking agent, a silane coupling agent, an additive, and the like may be further included. 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 may include a monomer mixture or a partial polymer thereof constituting the (meth) acrylic copolymer having the hydroxyl group, the alkyl group and the amide group, the organic nanoparticles and the initiator.

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.

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 as in any way limiting its scope.

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 1

, 80 parts by weight of 2-ethylhexyl acrylate (2-EHA), 19 parts by weight of 4-hydroxybutyl acrylate (4-HBA) and 1 part by weight of N, N-diethylacrylamide (DEAA) , 1.5 parts by weight of the organic nanoparticles of Production Example and 0.03 part by weight of Irgacure 651 (2,2-dimethoxy-2-phenylacetophenone, BASF) as an initiator were mixed well in the 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

80 parts by weight of 2-ethylhexyl acrylate, 18 parts by weight of 4-hydroxybutyl acrylate, 1 part by weight of N, N-diethylacrylamide and 1 part by weight of macromonomer AA-6 (Toakosei) , 2 parts by weight of the organic nanoparticles of Production Example and 0.03 part by weight of Irgacure 651 (2,2-dimethoxy-2-phenylacetophenone, BASF) as an initiator were mixed well in the reactor. The dissolved oxygen in the reactor was replaced with nitrogen gas, and the mixture was partially polymerized by irradiation with ultraviolet rays using a low pressure mercury lamp for several minutes to prepare a viscous liquid having a viscosity of 4000 to 9000 cps at 25 캜. 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. A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 using the pressure-sensitive adhesive composition.

Examples 3 to 5

The contents of 2-ethylhexyl acrylate, 4-hydroxybutyl acrylate, N, N-diethylacrylamide, macromonomer AA-6 and the preparation examples of organic nanoparticles in Example 2 were changed as shown in Table 1 A pressure-sensitive adhesive sheet was prepared in the same manner.

Example 6

In Example 1, 1 part by weight of N-hydroxyethyl acrylamide (HEAA) was used instead of 1 part by weight of N, N-diethylacrylamide, and the content of 2-ethylhexyl acrylate and 4-hydroxybutylacrylate A pressure-sensitive adhesive sheet was prepared in the same manner except that the pressure-sensitive adhesive sheet was changed as shown in Table 1 below.

Example 7

Except that 1 part by weight of N-hydroxyethyl acrylamide (HEAA) was used instead of 1 part by weight of N, N-diethylacrylamide in Example 2, to prepare a pressure-sensitive adhesive sheet.

Comparative Example 1

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, except that the contents of 2-ethylhexyl acrylate, 4-hydroxybutyl acrylate and N, N-diethylacrylamide were changed as shown in Table 1 below.

Comparative Example 2

A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, except that the organic nanoparticles were not used.

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) Peel strength: The corona was treated twice (total dose: 156 dose) on a PET film having a width × length × thickness (150 mm × 25 mm × 75 μm) while discharging the plasma at a dose of 78 dose using a corona processor. Adhesive film samples were obtained from the pressure-sensitive adhesive sheets of Examples and Comparative Examples to a size of 100 mm x 25 mm x 50 m (width x length x thickness). The corona-treated side of the PET film was laminated on both sides of the adhesive film sample to prepare the specimen shown in Fig. 2 (a). The specimen was autoclaved at a pressure of 3.5 bar at 50 ° C for 1000 seconds and the specimens were fixed on a TA.XT_Plus Texture Analyzer (Stable Micro System). Referring to FIG. 2 (b), one PET film was fixed at 25 ° C. and 60 ° C. in a TA.XT_Plus Texture Analyzer, and the other PET film was pulled at a rate of 50 mm / min to measure the peel strength.

(2) Rate of change in peel strength: The rate of change in peel strength was calculated according to the above formula (1) using the peel strength obtained in (1).

(3) Modulus (G '): The viscoelasticity was measured by ARES (Anton Paar MCR-501), a dynamic viscoelasticity measuring device, at a shear rate of 1 rad / sec and strain 1% under an auto strain condition. 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. The measurement was carried out at a temperature raising rate of 5 DEG C / min in a temperature range of -60 DEG C to 90 DEG C using an 8 mm jig, and the modulus was determined at -20 DEG C and 80 DEG C, respectively.

(4) Modulus ratio: Using the modulus obtained in (3), the modulus ratio was calculated according to Equation 2 above.

(5) Haze: Haze meter (model Nippon Denshoku Model NDH 5000) was used. 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").

(6) 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 -20 캜, bending the specimen at a radius of curvature of 3 mm, and bending at 30 cycles per minute. In this case, the specimen is bent and spread at the radius of curvature. Means a condition for bending 100,000 cycles. X when peeling or bubbling occurred after 100,000 cycles, and when the peeling and bubbling did not occur, it was indicated with.

Example Comparative Example One 2 3 4 5 6 7 One 2 2-EHA
(Parts by weight) 80 80 78 73 83 79 80 75 80 4-HBA
(Parts by weight) 19 18 20 25 15 20 18 25 19 DEAA
(Parts by weight) One One One One One - - - One HEAA
(Parts by weight) - - - - - One One - - Organic nanoparticles
(Parts by weight) 1.5 2 One 1.5 0.5 1.5 2 1.5 - Macro monomer (parts by weight) - One One One One - One - - Peel strength
(25 [deg.] C,
gf / in) 1190 1342 1062 1297 1101 1332 1240 1190 1011 Peel strength
(60 < 0 > C, gf / in) 1017 1083 1005 1064 930 1170 1098 584 689 Rate of change in peel strength 0.15 0.19 0.05 0.18 0.16 0.12 0.11 0.51 0.32 Modulus
(-20 < 0 > C, kPa) 83 75 84 81 71 72 88 108 107 Modulus
(80 < 0 > C, kPa) 31 32 29 29 28 30 33 15 15 Modulus ratio 2.68 2.34 2.90 2.79 2.54 2.40 2.67 7.2 7.13
Hayes
(%) 0.57 0.42 0.68 0.28 0.91 0.49 0.33 0.76 0.71 Folding evaluation
(-20 ° C) ○ ○ ○ ○ ○ ○ ○ X X

As shown in Table 1, the adhesive film of this example was minimized in the peel strength difference between high temperature and room temperature, and optically transparent. It is believed that the adhesive film of this embodiment has a high modulus at a high temperature, so that the reliability of the adhesive film at a high temperature is good. The pressure-sensitive adhesive film of this example exhibited good foldability.

On the other hand, Comparative Example 1, which does not contain an amide group monomer, and Comparative Example 2, which does not include an organic nanoparticle, have a high modulus at low temperature and are poor in folding property at low temperature and low in modulus at high temperature, have.

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

(Meth) acrylic copolymer and an organic nanoparticle having a hydroxyl group, an alkyl group and an amide group, wherein the rate of change of the peel strength of the formula (1) is 0.5 or less, the peel strength at 60 ° C is 700 gf /
The (meth) acrylic copolymer is prepared by copolymerizing 5 to 40% by weight of a hydroxyl group-containing (meth) acrylate, 55 to 90% by weight of an alkyl group-containing (meth) 10% by weight of a copolymer of a monomer mixture comprising:
&Lt; Formula 1 > Change rate of peel strength = | AB | / A
(In the above formula 1, A represents the peeling strength of the pressure-sensitive adhesive film at 25 ° C, and B represents the peeling strength of the pressure-sensitive adhesive film at 60 ° C).

The adhesive film according to claim 1, wherein the pressure-sensitive adhesive film has a modulus of 10 kPa to 100 kPa at -20 캜.

The adhesive film according to claim 1, wherein the adhesive film has a peel strength of from 500 gf / in to 5000 gf / in at 25 ° C.

The adhesive film according to claim 1, wherein the adhesive film has a peel strength of from 700 gf / in to 5000 gf / in at 60 ° C.

The pressure-sensitive adhesive film according to claim 1, wherein the pressure-sensitive adhesive film has a modulus ratio of 1.5 to 6,
&Quot; (2) " modulus ratio = C / D
(C is the modulus of the pressure-sensitive adhesive film at -20 deg. C, and D is the modulus of the pressure-sensitive adhesive film at 80 deg.

The pressure-sensitive adhesive film according to claim 1, wherein the pressure-sensitive adhesive film has a modulus of 20 kPa to 100 kPa at 80 캜.

The pressure-sensitive adhesive film according to claim 1, wherein the pressure-sensitive adhesive film has a haze of 1% or less at a wavelength of 380 nm to 780 nm.

The pressure-sensitive adhesive film according to claim 1, wherein the pressure-sensitive adhesive film is formed of a pressure-sensitive adhesive composition comprising the monomer mixture or a partial polymer thereof, the organic nanoparticles, and an initiator.

delete

The adhesive film of claim 1, wherein the monomer mixture further comprises a macromonomer.

delete

The adhesive film according to claim 1, wherein the organic nanoparticles have an average particle diameter of 10 nm to 400 nm.

The adhesive film according to claim 1, wherein the organic nanoparticles are core-shell type particles.

14. The adhesive film according to claim 13, 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.

The pressure-sensitive adhesive film according to claim 1, wherein the organic nanoparticles are contained in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the monomer mixture constituting the (meth) acrylic copolymer having hydroxyl, alkyl and amide groups.

14. The adhesive film of claim 13, wherein the core is formed of at least one of polybutyl acrylate, polysiloxane, and the shell is polymethyl methacrylate.

delete

The composition according to claim 10, wherein the monomer mixture comprises 5 to 40% by weight of the hydroxyl group-containing (meth) acrylate, 55 to 90% by weight of the alkyl group-containing (meth) 0.1 to 10% by weight, and 0.1 to 20% by weight of the macromonomer.

The pressure-sensitive adhesive film according to claim 8, wherein the pressure-sensitive adhesive composition further comprises at least one of a silane coupling agent and a crosslinking agent.

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 8, 10, 12 to 16, and 18 to 19.

An optical display device comprising the adhesive film of any one of claims 1 to 8, 10, 12 to 16, and 18 to 19.