KR101758420B1 - Adhesive composition, adhesive film prepared using the same and optical display apparatus comprising the same - Google Patents

Abstract

The present invention relates to a thermosetting resin composition comprising an alicyclic group-containing (meth) acrylic copolymer, an epoxy compound, an initiator and a crosslinking agent, wherein the epoxy compound is contained in an amount of 5 to 35 parts by weight based on 100 parts by weight of the alicyclic group- An adhesive film containing the same, and an optical display device including the same.

Description

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

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

Optical clear adhesive (OCA) films are used as interlayer adhesives for laminating components in an optical display device or in touch screen attachment of mobile phones as adhesive films. In particular, a capacitive type touch pad of an optical display device is attached to a window or a film by an adhesive film to detect a change in capacitance of a window or a film. In the touch pad, the adhesive film is laminated between a window glass and a touch screen panel (TSP) sensor glass. OCA film transmits light more than 97% and functions like glass, but it has better screen sharpness and better adhesive property than conventional double-sided tape. OCA film can be used not only for mobile phones but also for Tablet PCs and TVs whose display screens are medium and large size. In this regard, Korean Patent Publication No. 2010-0019401 discloses an optical film composition.

An object of the present invention is to provide a pressure-sensitive adhesive film which is excellent in step-gap filling property, durability and reliability, and is free from bubble formation during the lamination process.

Another object of the present invention is to provide a pressure-sensitive adhesive composition which can improve the durability, cuttability, and filling property and can minimize the increase in ITO resistance while satisfying a low dielectric constant (dielectric constant: 3.5 or less).

It is still another object of the present invention to provide a pressure-sensitive adhesive composition which can simultaneously increase cationic polymerization and radical polymerization to improve the crosslinking structure of the pressure-sensitive adhesive, reduce the storage modulus at high temperatures, and increase the reactivity of the silane.

It is still another object of the present invention to provide a pressure-sensitive adhesive composition which does not cause end-lift, bubble, warpage or the like due to outgassing.

The pressure-sensitive adhesive composition of the present invention comprises a (meth) acrylic copolymer containing an alicyclic group, an epoxy compound, an initiator, and a crosslinking agent, wherein the epoxy compound is contained in an amount of 5 to 35 parts by weight per 100 parts by weight of the alicyclic group- .

The pressure-sensitive adhesive film of the present invention may include the pressure-sensitive adhesive composition or may be formed of the pressure-sensitive adhesive composition.

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 having good step-gap filling property, good durability, and no bubbles during the lamination process. INDUSTRIAL APPLICABILITY The present invention provides a pressure-sensitive adhesive composition which can improve the durability, cuttability and filling property and can minimize the increase in ITO resistance while satisfying a low dielectric constant (dielectric constant: 3.5 or less). The present invention provides a pressure-sensitive adhesive composition which can simultaneously increase cationic polymerization and radical polymerization to improve cross-linking structure of the pressure-sensitive adhesive, thereby decreasing the storage modulus at a high temperature and increasing the reactivity of the silane. The present invention provides a pressure-sensitive adhesive composition that does not cause end-lift, bubble, warpage, or the like due to outgassing.

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. In the present specification, '(meth) acrylate' means acrylate and (meth) acrylate, and 'upper' and 'lower' are defined with reference to the drawings, Lower 'to' upper '.

The pressure sensitive adhesive composition according to one embodiment of the present invention comprises a (meth) acrylic copolymer containing an alicyclic group, an epoxy compound, an initiator and a crosslinking agent, wherein the epoxy compound is contained in an amount of 5 to 35 parts by weight per 100 parts by weight of the alicyclic group- . If the epoxy compound is contained in an amount of less than 5 parts by weight, bubbling may occur during film formation, and if it exceeds 35 parts by weight, durability and reliability may be poor. Specifically, the epoxy compound may be contained in an amount of 10 to 30 parts by weight based on 100 parts by weight of the alicyclic group-containing (meth) acrylic copolymer.

(A1) a monomer mixture comprising an alkyl (meth) acrylate having a C7-C20 alkyl group, (a2) an alicyclic group-containing (meth) acrylate and (a3) a hydroxyl group-containing monomer ≪ / RTI >

The alkyl (meth) acrylate having a C7-C20 alkyl group may include a (meth) acrylic acid ester having a linear or branched C7-C20 alkyl group. (Meth) acrylate, undecyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (Meth) acrylate, and the like, but not always limited thereto, and they may be used alone or in combination of two or more. The use of an alkyl (meth) acrylate having a C7-C10 alkyl group preferably has an effect of increasing the initial adhesive force and increasing the wetting property on the substrate.

The alkyl (meth) acrylate having a C7-C20 alkyl group is contained in the monomer mixture or the (meth) acrylic copolymer in an amount of 40 to 60% by weight, specifically 45 to 65% by weight, such as 45,46,47,48, And may be contained in an amount of from 0.1 to 50% by weight based on the total weight of the composition. And excellent adhesion and excellent durability can be obtained.

Alicyclic (meth) acrylates are C3-C20 alicyclic (meth) acrylates. Examples thereof include, but are not limited to, isobornyl (meth) acrylate, bornyl (meth) acrylate, cyclohexyl (meth) acrylate, cyclopentyl Two or more of them may be mixed and applied. Preferably, the use of (C10-C15) alicyclic (meth) acrylate may further enhance durability.

(Meth) acrylate containing an alicyclic group is contained in an amount of 10 to 30% by weight, specifically 15 to 25% by weight, for example, 15, 16, 17, 18, 19, 20, , 22, 23, 24, 25% by weight. The heat resistance / durability in the above range can be increased, and the adhesion force can be increased.

The hydroxyl group-containing monomer may be at least one selected from the group consisting of 2-hydroxyethyl (meth) acrylate having a hydroxyl group, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) (Meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, chloro-2-hydroxypropyl (meth) acrylate, diethylene glycol mono (Meth) acrylate having a C 1 -C 20 alkyl group or a C 5 -C 20 cycloalkyl group having a hydroxyl group, And C1-C10 unsaturated alcohols including allyl alcohol and the like, but not always limited thereto, and they may be used alone or in combination of two or more. The use of a (meth) acrylate having a C1-C5 alkyl group having a hydroxyl group preferably has an effect of improving adhesion and increasing durability.

The hydroxyl group-containing monomer is used in an amount of 10 to 40% by weight, specifically 15 to 25% by weight, for example, 15, 16, 17, 18, 19, 20, 21, 22, , And 25% by weight. In this range, the adhesive strength is increased, the durability is excellent, and the bubbles are not generated under the moisture-resistant condition.

The (meth) acrylic copolymer containing an alicyclic group may further contain a hetero-alicyclic group to further lower the hardening shrinkage ratio. (A1) an alkyl (meth) acrylate having a C7-C20 alkyl group, (a2) an alicyclic (meth) acrylate, (a3) a (meth) acrylate having an alicyclic group, A hydroxyl group-containing monomer, and (a4) a heteroalicyclic group-containing (meth) acrylate.

The (meth) acrylate containing a heteroalicyclic group may include (meth) acrylic monomers having C4-C6 and a single ring hetero-alicyclic group having nitrogen, oxygen or sulfur. For example, (meth) acryloylmorpholine, and the like.

The (meth) acrylate containing a heteroalicyclic group is contained in the monomer mixture or the (meth) acrylic copolymer in an amount of 0.1 to 10% by weight, specifically 1 to 5% by weight, for example, 1,2,3,4,5% And may have a low hardening shrinkage ratio and good reliability in the above range.

The (meth) acrylic copolymer containing an alicyclic group may further have a durability by improving the adhesion and the adhesion of the base material by further including a carboxylic acid group. (A1) an alkyl (meth) acrylate having a C7-C20 alkyl group, (a2) an alicyclic group-containing (meth) acrylate, (a3) a hydroxyl group A monomer and (a5) a monomer mixture containing a carboxylic acid group-containing monomer.

The monomer containing carboxylic acid groups may be (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, and they may be used alone or in combination of two or more.

The carboxylic acid group-containing monomer may be contained in the monomer mixture or the (meth) acrylic copolymer in an amount of 0 to 3% by weight. Within the above range, the adhesive strength can be increased, the durability can be improved, and the surface corrosion resistance of the transparent electrode film can be improved. Preferably 0 to 2% by weight, more preferably 0 to 1.5% by weight, and most preferably 0 to 1% by weight.

(Meth) acrylic copolymer may be polymerized together with addition of other copolymerizable monomers besides the above-mentioned monomers. (Meth) acrylate having a pyrrolidonyl group, (meth) acrylate having a phosphate group, and the like.

The (meth) acrylic copolymer may have a glass transition temperature (Tg) of -35 캜 to -10 캜, preferably -30 캜 to -13 캜. In the above range, the workability is excellent, and durability and adhesive strength are excellent.

The (meth) acrylic copolymer may have a viscosity at 25 ° C of 1600 to 8000 cPs, preferably 1500 to 5000 cPs, and more preferably 1500 to 3000 cPs.

(Meth) acrylic copolymer has a weight average molecular weight of 1,000 to 3,000,000 g / mol, preferably 1,500 to 2,500,000 g / mol, for example, 1,500,000, 1,600,000, , 2 million, 2.1 million, 2.2 million, 2.3 million, 2.4 million, and 2.5 million g / mol. Within the above-mentioned range, the pressure-sensitive adhesive composition can be cured to have durability even after being left in a high temperature and high humidity condition for a long time during production of the pressure-sensitive adhesive film, and the pressure-

The (meth) acrylic copolymer may be produced by a conventional method. Specifically, it can be prepared by mixing a monomer mixture with a photo-radical initiator and subjecting the mixture to solution polymerization, suspension polymerization, photopolymerization, bulk polymerization, or emulsion polymerization. Specifically, the solution polymerization can be carried out at 50 to 100 ° C by adding a photo-radical initiator to the monomer mixture, and the photo-radical initiator is reacted with an acetophenone-based radical containing 2,2-dimethoxy- A photopolymerization initiator can be used. The photo-radical initiator may be used in an amount of 0.01-3 parts by weight, preferably 0.01-1 parts by weight, based on 100 parts by weight of the monomer mixture for the production of the (meth) acrylic copolymer. In this range, low light leakage and excellent endurance reliability can be obtained.

The (meth) acrylic copolymer may be prepared by completely polymerizing the monomer mixture, or the monomer mixture may be partially polymerized and then the polymerization may be completed after further adding an initiator and a crosslinking agent. Partial polymerization is carried out until the monomer mixture is polymerized to a viscous liquid having a viscosity at 25 占 폚 of 1,000 to 50,000 cPs, preferably 1,000 to 6,000 cps, more preferably 1,500 to 3,000 cps. The coating is easy in the viscosity range and the workability is excellent.

The epoxy compound has two or more epoxy groups and is cured by a photo cationic initiator, which can be included in an adhesive film to enhance durability. Specifically, the epoxy compound is an epoxy compound having an alicyclic group and may include two or more, for example, two to four alicyclic groups each having at least one epoxy group. Particularly, the use of the (meth) acrylic copolymer having an alicyclic group and the epoxy compound having an alicyclic group together can further enhance the effect of the adhesive film of the present invention.

For example, the epoxy compound may be glycidyl ether such as tetramethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, bisphenol A diglycidyl ether, , Epoxy esters such as bisphenol A-diepoxy-acrylic acid adducts and mixtures thereof, monomers and oligomers of alicyclic epoxies, mixtures thereof, and the like, but are not limited thereto. The alicyclic epoxy may be represented by the following general formulas (1a), (1b), (1c), (1d) and (1e)

<Formula 1a>

&Lt; EMI ID =

&Lt; Formula 1c >

<Formula 1d>

<Formula 1e>

The epoxy compound may be contained in an amount of 5 to 35 parts by weight, specifically 10 to 30 parts by weight, based on 100 parts by weight of the (meth) acrylic copolymer. Bubbles are not generated in the film in the above range and reliability can be improved.

The initiator may comprise at least one of a photo-radical initiator, a photo-cation initiator, and preferably a mixture of photo-radical initiator and photo-cation initiator. The photo-radical initiator cures the (meth) acrylic copolymer and the photo-cation initiator cures the epoxy compound. Therefore, cationic polymerization and radical polymerization are simultaneously caused to improve the cross-linking structure of the pressure-sensitive adhesive, so that the decrease of the storage modulus at a high temperature is small and the reactivity of the silane can be increased.

Details of the photo radical initiator are as described above. The photo-radical initiator may be included in an amount of 0.001 to 5 parts by weight, preferably 0.01 to 3 parts by weight, more preferably 0.01 to 1 part by weight based on 100 parts by weight of the monomer mixture or the (meth) acrylic copolymer. Within this range, the (meth) acrylate-based compound may be sufficiently cured and the effect of improving the reactivity of the photocationic polymerization initiator may be obtained.

The photo cationic initiator may be a conventional photo cationic initiator capable of carrying out a photo-curable reaction. Examples thereof include, but are not limited to, onium salts such as aromatic diazonium salts, aromatic iodo aluminum salts, and aromatic sulfonium salts, iron-arene complexes, and mixtures thereof. Specific examples of the cation include a diaryl such as diphenyl iodonium, 4-methoxydiphenyl iodonium, bis (4-methylphenyl) iodonium, bis (4-tert- butylphenyl) iodonium, bis (dodecylphenyl) (Diphenylsulfonium) -phenyl] sulfide, bis [4- (di (methanesulfonylphenyl) sulfide, diphenylsulfonium iodide, triphenylsulfonium and diphenyl- (Cyclopentadienyl) [1,2,3,4,5,6-.eta.] - (4- (2-hydroxyethyl) (Methylethyl) -benzene] -iron (1+). Specific examples of the anion include tetrafluoroborate (BF ₄ ^- ), hexafluorophosphate (PF ₆ ^- ), hexafluoroantimonate (SbF ₆ ^- ), hexafluoroarsenate (AsF ₆ ^- And chlorantimonate (SbCl ₆ ^- ). The photo cationic initiator may be contained in an amount of 0.01 to 3 parts by weight, preferably 0.5 to 1.5 parts by weight, based on 100 parts by weight of the epoxy resin. In this range, polymerization of the epoxy compound can be sufficiently carried out, have.

The crosslinking agent may preferably be a polyfunctional (meth) acrylate capable of curing with an active energy ray. Examples of the polyfunctional (meth) acrylate include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol Di (meth) acrylate, neopentylglycol adipate di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, (Meth) acrylates such as ethylene oxide modified di (meth) acrylate, di (meth) acryloxy ethyl isocyanurate, allyl cyclohexyl di (meth) acrylate, tricyclodecane dimethanol Di (meth) acrylate, ethylene oxide modified hexahydrophthalic acid di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate, neopentyl glycol modified trimethylpropane (Meth) acrylate, adamantane (adamantane) di (meth) acrylate or 9,9-bis [4- (2-oxy-yl acrylate) phenyl] fluorene difunctional acrylate and the like; (Meth) acrylates such as trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri 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; And dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate or urethane (meth) acrylate (e.g., an isocyanate monomer and trimethylolpropane tri But are not limited thereto. These may be used alone or in admixture of two or more. Preferably, the polyhydric alcohol having 2 to 20 hydroxyl groups (metha ) Acrylate.

The crosslinking agent may be contained in an amount of 0.01 to 1 part by weight, specifically 0.1 to 1 part by weight, specifically 0.05 to 1 part by weight, based on 100 parts by weight of the (meth) acrylic copolymer, and the effect of the pressure- have.

An isocyanate-based, epoxy-based, aziridine-based, melamine-based, amine-based, imide-based, carbodiimide-based, amide-based cross-linking agent or a combination thereof may be used.

In an embodiment, the pressure-sensitive adhesive composition comprises 5 to 35 parts by weight of an epoxy compound, 0.01 to 3 parts by weight of a photo radical initiator, 0.01 to 1 part by weight of a crosslinking agent, 100 parts by weight of an epoxy compound 100 And 0.01 to 3 parts by weight of a photo cationic initiator based on the weight of the composition. In this range, there may be no problems such as step embeddability, durability, no bubbles, and outgassing.

The pressure-sensitive adhesive composition may optionally contain a silane coupling agent (silane compound), a curing accelerator, an ionic liquid, a lithium salt, an inorganic filler, a softener, an antioxidant, an antioxidant, a stabilizer, (Coloring pigment, extender pigment, etc.), a treating agent, an ultraviolet ray blocking agent, an antioxidant, an antioxidant, a coloring agent, A fluorescent brightening agent, a dispersing agent, a heat stabilizer, a light stabilizer, an ultraviolet absorber, an antistatic agent, a lubricant and a solvent.

The silane coupling agent may further include, but is not limited to, an epoxy group-containing silane coupling agent. The epoxy group-containing silane coupling agent improves the adhesion between the pressure-sensitive adhesive and the glass substrate and improves the adhesion stability, improves heat resistance and moisture resistance, and improves adhesion reliability even when the pressure-sensitive adhesive is left standing for a long time under high temperature and / You can. Furthermore, the pressure-sensitive adhesive composition of the present invention can simultaneously perform radical polymerization and cationic polymerization, so that the reactivity of the silane (silane coupling agent) can be increased. The epoxy group-containing silane coupling agent may be contained in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the (meth) acrylic copolymer.

In an embodiment, an oligomer-type siloxane represented by the following formula (2) may be used as the epoxy group-containing silane coupling agent. By using oligomeric siloxane, the effect of the present invention can be further enhanced.

(2)

Wherein R ₁ , R ₂ and R ₃ are each independently an alkyl group having 1 to 5 carbon atoms, R ₄ and R ₅ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, n is an integer of 3 to 25, and m is an integer of 1 to 10. Preferably R &_lt; ₁ &gt;, R &lt; ₂ &gt; and R &lt; ₃ &gt; may be methyl, ethyl or propyl groups.

The oligomeric siloxane may have a viscosity at 25 占 폚 of 15 to 40 cps, preferably 20 to 35 cps. Within this range, coating properties may be good.

The oligomeric siloxane may have a refractive index of 1.4 to 1.5 and may be suitably applied to the optical member in the above range.

The oligomeric siloxane may have an alkoxy group content of 30 to 60% by weight, preferably 35 to 55% by weight in the molecule. In the above range, it has excellent durability, adhesive force and reworkability.

The oligomeric siloxane may have an epoxy equivalent of 250 to 450 g / eq, preferably 300 to 400 g / eq. And has excellent adhesion and re-peelability in the above range.

The content of the epoxy group-containing silane coupling agent is 0.01 to 5 parts by weight, preferably 0.1 to 1 part by weight, based on 100 parts by weight of the (meth) acrylic copolymer containing the alicyclic group. Within the above range, the substrate adhesion and durability and long-term storage characteristics are good.

The pressure-sensitive adhesive composition can be used for adhesion of an optical film including a polarizing film and a transparent electrode film.

The pressure-sensitive adhesive film of one embodiment of the present invention may be formed of the pressure-sensitive adhesive composition.

In one embodiment, the pressure sensitive adhesive film may comprise the pressure sensitive adhesive composition. For example, the pressure-sensitive adhesive composition may be coated on a release film (e.g., a polyester, a polyethylene terephthalate film) and dried. The pressure-sensitive adhesive film may contain the (meth) acrylic copolymer, the epoxy compound, the initiator, the cross-linking agent and the like in a state where the pressure-sensitive adhesive composition is not completely cured. In other embodiments, the adhesive film may comprise a cured product of the pressure sensitive adhesive composition. For example, the pressure-sensitive adhesive composition may be coated on a release film (e.g., polyester, polyethylene terephthalate film) and UV-cured. UV curing can be carried out at 0.1 to 40 mW / cm ² for 1 to 5 minutes. Preferably, oxygen can be cured in the blocked state.

The thickness of the coating is not particularly limited and may be 50 탆 to 2 mm, preferably 50 탆 to 1.5 mm. The adhesive film finally produced in the above range can be used in an optical display device.

The thickness of the pressure-sensitive adhesive film (thickness excluding the release film) is not particularly limited, but may be from 10 탆 to 2 mm, preferably from 100 탆 to 1.5 mm, and can be used in an optical display device in the above range.

The adhesive film can be used as optical clear adhesive (OCA) film or touch panel film.

The adhesive film has a dielectric constant of 3.5 or less, preferably 3.5 to 3.0, measured at 400 kHz using an LCR meter (manufacturer: agilent product name: E4980A) Excellent in reliability and touch sensitivity in the range.

The pressure-sensitive adhesive film has a resistance change rate (R) represented by the following formula (1): 0 to less than 5%, preferably more than 0 to less than 4%, more preferably 0 to 3% .

[Equation 1]

(In the above formula (1), P ₂ is the resistance after the pressure-sensitive adhesive film is left at 60 ° C / 90% relative humidity for 240 hours, and P ₁ is the initial resistance of the pressure-sensitive adhesive film.

The adhesive film may have a storage elastic modulus at 30 ° C of ¹ x 10 ⁵ to ⁵ x 10 ⁷ dyne / cm ² , preferably ¹ x 10 ⁶ to 5 x 10 ⁷ dyne / cm ² , and a storage elastic modulus at 80 ° C of ¹ x 10 ⁴ to 2 x 10 ⁶ dyne / cm ² , Preferably from 9x10 &lt; ⁴ &gt; to 1x10 &lt; ⁶ &gt; dyne / cm &lt; ² &gt;. The cross-linking structure of the pressure-sensitive adhesive film is excellent in the above-mentioned range, and micro-bubbles due to gas outgassing can be prevented with respect to PC Sheet, PC Film and the like. The storage elastic modulus was measured using a frequency sweep test (frequency: 1 Hz) at 30 DEG C and 80 DEG C using an advanced reometric expansion system (ARES) (TA).

The peel strength of the adhesive film measured according to the physical property evaluation method of the following examples may be 1,950 gf / 25 mm to 3,000 gf / 25 mm.

The optical display device of one embodiment of the present invention may include an adhesive film of one embodiment of the present invention. Specifically, the optical display device includes an optical film; And an adhesive film attached to one side or both sides of the optical film, and the adhesive film may include the adhesive film of one embodiment of the present invention.

Examples of the optical film include a touch panel, a window, 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, Transparent electrode films such as plastic LCD substrates, indium tin oxide (ITO), fluorinated tin oxide (FTO), aluminum doped zinc oxide (AZO), carbon nanotubes (CNT), Ag nanowires and graphene . The method for producing the optical film can be easily manufactured by a person having ordinary skill in the art to which the present invention belongs.

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

1, an organic light emitting diode display 100 includes a substrate 10, an OLED element 15 formed on the substrate 10, a sealing layer 20 for sealing the OLED element 15, A first adhesive film 25 formed on the layer 20 and a substrate 35 formed on the first adhesive film 25 and a first transparent conductive layer 40 formed on the substrate 35 and a substrate 35 A polarizing plate 45 formed on the upper portion of the first transparent conductive layer 40 and a second adhesive film 50 formed on the upper portion of the polarizing plate 45. [ And a window 55 formed on top of the second adhesive film 50 and at least one of the first adhesive film 25 and the second adhesive film 50 may be an adhesive film of the embodiment of the present invention .

The substrate 10 may be a substrate (e.g., a TFT substrate) commonly used in an organic light emitting diode display device. Specifically, the substrate 10 may be a glass substrate, a plastic polyimide, an epoxy, an acrylic, It may be a substrate having flexibility.

Although not shown in FIG. 1, the OLED element 15 includes a first electrode, a second electrode, an organic light emitting layer formed between the first electrode and the second electrode, The organic light-emitting film may be formed by sequentially laminating a hole injection layer, a hole transporting layer, a light emitting layer, an electron transporting layer, and an electron injecting layer, but is not limited thereto.

The sealing layer 20 protects the OLED element 15 from external moisture or oxygen and may be formed of an inorganic, organic or inorganic / organic mixture.

The transparent conductor includes a base material 35 and a first transparent conductive layer 40 formed on both surfaces of the base material 35 and a second transparent conductive layer 30 can do. The first transparent conductive layer 40 and the second transparent conductive layer 30 may be the same or different from each other. The substrate 35 may be an optical transparent film (e.g., a polyester including polycarbonate, polyethylene terephthalate or the like) And may be an indium tin oxide (ITO) film, or a film containing a metal nanowire. Although not shown in FIG. 1, the first transparent conductive layer 40 and / Or the second transparent conductive layer 30 may be patterned.

The first adhesive film 25 adheres the sealing layer 20 and the second transparent conductive layer 30 and the second adhesive film 50 adheres the first transparent conductive layer 40 and the window 55, May be the same or different, and may include, but not limited to, an adhesive film of one embodiment of the present invention.

The polarizing plate 45 has an anti-reflection function in the organic light emitting display and may include, but not limited to, a polarizer, a protective film formed on the polarizer and / or a retardation film, though not shown in FIG.

The window 55 serves as a display, and may be formed of glass or a plastic material, or may be formed of a material having flexibility.

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

Hereinafter, the present invention will be described in more detail by way of examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

(A) a monomer for a (meth) acrylic copolymer: EHA (2-ethylhexyl acrylate), IBOA (isobornyl acrylate), HEA (2-hydroxyethyl acrylate), ACMO (acryloylmorpholine)

(B) Epoxy compound: CY179 (manufactured by HuntSman)

<Formula 1a>

(C) Initiator: (C1) Photo radical initiator: Irgacure 651 (2,2-dimethoxy-2-phenylacetophenone) (Shiba Japan K.K.), (C2) Photo cation initiator: CPI210S Pro)

(D) Crosslinking agent: HDDA (1,6-hexanediol diacrylate)

(E) Silane coupling agent: Siloxane-based epoxy silane (X-41-1059A, manufactured by Shinetsu), (KBM-403, Shinetsu)

Example  One

50 parts by weight of ethylhexyl acrylate (EHA), 25 parts by weight of isobornyl acrylate (IBOA), 25 parts by weight of hydroxyethyl acrylate (HEA), and 2,2-dimethoxy-2-phenyl 0.04 part by weight of acetophenone (product name: Irgacure ™ 651, manufacturer: Shiba Japan) were mixed in a glass container to prepare a mixture. After the dissolved oxygen was replaced with nitrogen gas, the mixture was polymerized by irradiation with ultraviolet rays using a low-pressure lamp (sylvania Lamp BL360) to obtain a (meth) acrylic copolymer having a cycloaliphatic group having a viscosity of about 1,500 cps Respectively. 0.1 part by weight of 1,6-hexane diol diacrylate (HDDA) as a polyfunctional (meth) acrylate, 0.5 parts by weight of an epoxy group-containing silane coupling agent (trade name: KBM-403, manufactured by Shinetsu ) And 0.16 part by weight of 2,2-dimethoxy-2-phenylacetophenone (product name: Irgacure ™ 651, manufacturer: Shiba Japan) as a photo radical initiator were added and mixed, and an epoxy mixture (product name: CY179 , 10 parts by weight of a product manufactured by Huntsman) and 0.15 part by weight of a cationic initiator (product name: CPI210S, manufactured by SANA PRO) were mixed to prepare a pressure-sensitive adhesive composition. The resulting pressure-sensitive adhesive composition was coated on a 50 탆 thick polyester film (release film) to form a pressure-sensitive adhesive film having a thickness of 175 탆. In order to remove oxygen adversely affecting the polymerization, a polyester film (release film) having a thickness of 50 mu m was coated on the pressure-sensitive adhesive film, a low pressure lamp (sylvania Lamp BL360) was used for both sides of the release film for about 3 minutes, A transparent adhesive film was prepared by irradiating ultraviolet rays (UV) at 1,500 mJ / cm ² with an ultraviolet intensity of 800 mW / cm ² using a high-pressure metal halide lamp (manufacturer: Litzen, device name: UV curing machine).

Example  2

Except that an epoxy group-containing siloxane coupling agent (trade name: X-41-1059A, manufacturer: Shinetsu) was used in place of the epoxy group-containing silane coupling agent (product name: KBM-403, manufacturer: Shinetsu) To prepare a pressure-sensitive adhesive composition and a pressure-sensitive adhesive film.

Example  3 to 5

(A), 0.04 parts by weight (C1) of the content described in Table 1 (parts by weight) shown below in 100 parts by weight of a monomer mixture containing 2 parts by weight of ACMO, 58 parts by weight of EHA, 20 parts by weight of IBOA and 20 parts by weight of HEA, Was mixed well in a glass vessel, the dissolved oxygen was replaced with nitrogen gas, and the mixture was partially polymerized by irradiating with ultraviolet light using a low-pressure lamp for several minutes to obtain a viscous liquid having a viscosity of about 1,500 cP. The pressure-sensitive adhesive composition was prepared by adding (E) residual amounts of (C1), (D), (B), and (C2) to the resulting composition in the amounts shown in Table 1 (parts by weight) .

The resulting composition was coated on a polyester film (release film, polyethylene terephthalate film) having a thickness of 50 탆 to prepare a transparent pressure-sensitive adhesive sheet 1 comprising the pressure-sensitive adhesive film 1 having a thickness of 175 탆.

In order to remove oxygen adversely affecting the polymerization, the release film was covered with the transparent pressure-sensitive adhesive sheet 1, and then a low-pressure lamp was irradiated from both surfaces of the release film for about 3 minutes to obtain an adhesive film 2 having a thickness of 175 탆 Whereby a transparent pressure-sensitive adhesive sheet 2 was produced.

In the reliability evaluation, the OCA film was laminated on the ITO film, and 2000 mj was irradiated on the metal halide lamp.

Comparative Example  One

A pressure-sensitive adhesive composition and a pressure-sensitive adhesive film were prepared in the same manner as in Example 1, except that the cationic photoinitiator CPI210S and the epoxy compound CY179 were not used.

Comparative Example  2 and 3

Except that the contents of the components (A), (B), (C), (D), and (E) were changed as shown in the following Table 1, transparent adhesive sheets 1 and 2 .

The following properties of the pressure-sensitive adhesive films of Examples and Comparative Examples were evaluated and shown in Table 1.

(1) Bubble generation at the time of laminating: The adhesive film 2 was laminated on the ITO film, autoclaved and visually evaluated for the occurrence of bubbles. X was evaluated when no air bubbles were generated, and was evaluated as good when at least one air bubble occurred.

(2) Curing shrinkage (%): The specific gravity of the liquid composition and the specific gravity of the solid after curing were measured by a digital solid viscometer DME-220E (Shinko, Japan). 5 g of the composition was coated to a thickness of 10 袖 m 賊 2 袖 m and then a film (thickness: 8 to 12 袖 m, width of 1.5 to 2.5 cm, length of 1.5 to 2.5 cm) was prepared by UV curing (100 mW / . The curing shrinkage ratio can be calculated according to the following equation (1).

<Formula 1>

Cure shrinkage ratio (%) = [(solid specific gravity after curing-specific gravity of liquid composition before curing)] / specific gravity of liquid composition before curing x 100

(3) Change in resistance (DELTA R,%): The adhesive film 2 was attached to ITO PET, and electrodes were formed on both sides using silver paste to prepare a sample. Thereafter, the initial resistance (P1) was measured for the manufactured sample, and the resistance P2 was measured again after the sample was left for 240 hours at 60 DEG C / 90% relative humidity. The resistance was measured using a Checkman portable resistance, voltage and current meter (manufactured by TaeKwang Electronics). Then, the resistance change rate (? R,%) was measured by substituting the resistance values measured under the respective conditions into the following equation (1)

&Quot; (1) &quot;

(Where P ₂ is the resistance after standing for 240 hours at 60 ° C / 90% relative humidity and P ₁ is the initial resistance).

(4) Reliability: After bonding the PC film / ITO film / glass and PET film, the film was allowed to stand at 60 ° C / 90% relative humidity for 500 hours and then visually observed for peeling, peeling, Observed and evaluated according to the following criteria

<Evaluation Criteria>

Good: Good (no bubbles or peeling)

?: Good (bubbles or peeling phenomenon somewhat)

X: poor (large amount of bubbles or peeling occurred)

(5) Peel strength (gf / 25 mm): The resulting adhesive film was attached to the ITO film using a PET film (backing film) having a thickness of 50 탆, and after a lapse of 30 minutes from the attachment, : TA.XT_Plus, manufacturer: Stable Micro System), the peel force was measured at a speed of 300 mm / min.

The peeling force was measured in the same manner as in Examples 3 to 5 after 30 minutes from the irradiation with 2000 mj of a metal halide lamp attached to ITO.

(6) Durability: After bonding the PC film / ITO film / glass and PET film, the film was allowed to stand at 60 ° C / 90% relative humidity for 500 hours, and then visually observed for peeling, peeling, Observed and evaluated according to the following criteria

<Evaluation Criteria>

Good: Good (no bubbles or peeling)

?: Good (bubbles or peeling phenomenon somewhat)

X: poor (large amount of bubbles or peeling occurred)

(7) Dielectric constant: Measured under the condition of 400 kHz using an LCR meter (manufacturer: agilent product name: E4980A). The thickness of the adhesive was measured to be 1 mm.

(8) Storage elasticity (unit: dyne / cm ² ): Frequency sweep test (frequency: 1 Hz) at 30 ° C. and 80 ° C. using an advanced reometric expansion system (ARES) Respectively.

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Copolymer EHA 50 50 58 58 58 50 58 58 IBOA 25 25 20 20 20 25 20 20 HEA 25 25 20 20 20 25 20 20 ACMO - - 2 2 2 - 2 2 Epoxy compound 10 10 10 20 30 - 50 - Initiator Radical photoinitiator 0.2 0.2 0.3 0.3 0.3 0.2 0.3 0.3 Cation photoinitiator 0.15 0.15 0.1 0.2 0.3 - 0.5 0 Cross-linking agent 0.1 0.1 0.2 0.2 0.2 0.1 0.2 0.2 Silane coupling agent KBM-403 0.1 - 0.1 0.1 0.1 0.1 0.1 - X-41-1059A - 0.1 - - - - - - Final form film film film film film film film film Manufacturing method UV curing UV curing UV curing UV curing UV curing UV curing UV curing UV curing Bubble formation at jointing X X X X X X X O Cure shrinkage (%) - - Within 0.1% Within 0.1% Within 0.1% - Within 0.1% Within 0.1% Rate of change in resistance (%) <2 <2 <2 <2 <2 <2 <2 <2 responsibility - - O O O - △ △ Peel strength
(gf / 25 mm) 2,100 2,100 2500 3000 3500 1,930 150 1800 Durability (PC) O O O O O X X X permittivity 3.5 3.5 3.5 3.4 3.3 3.9 3.2 4.3 Storage elasticity (30 ° C) 1.2 * 10 ^ 7 1.2 * 10 ^ 7 1.3 * 10 ^ 7 2.3 * 10 ^ 7 3 * 10 ^ 7 6 * 10 ^ 6 5 * 10 ^ 7 3.5 * 10 ^ 6 Storage elasticity (80 캜) 2.3 * 10 ^ 6 2.3 * 10 ^ 6 2.3 * 10 ^ 6 3.4 * 10 ^ 6 4 * 10 ^ 6 2.1 * 10 ^ 4 5 * 10 ^ 6 4 * 10 ^ 5

As shown in Table 1, the adhesive film of the present invention had no problem of bubble generation at the time of laminating, and the durability reliability was good. On the other hand, in the comparative example, outgassing of the PC which is not surface treated in the reliability condition caused bubbles or lifting.

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 (19)

(Meth) acrylic copolymer containing an alicyclic group,
Epoxy compounds,
Initiator, and
A crosslinking agent,
The epoxy compound is contained in an amount of 5 to 35 parts by weight based on 100 parts by weight of the alicyclic group-containing (meth) acrylic copolymer.
The epoxy compound contains two or more epoxy groups,
The epoxy compound is an epoxy compound having an alicyclic group,
(A1) an alkyl (meth) acrylate having a C7-C20 alkyl group, (a2) an alicyclic group-containing (meth) acrylate, (a3) a monomer containing a hydroxyl group-containing monomer Copolymer of the mixture,
Wherein the pressure-sensitive adhesive film obtained by curing the pressure-sensitive adhesive composition has a dielectric constant measured at 400 kHz of 3.5 or less. delete The pressure-sensitive adhesive composition according to claim 1, wherein the monomer mixture comprises 40-60 wt% of the (a1), 10-30 wt% of the (a2), and 10-40 wt% of the (a3). The pressure-sensitive adhesive composition according to claim 1, wherein the monomer mixture further comprises (a4) a (meth) acrylate containing a heteroalicyclic group. The composition according to claim 4, wherein the monomer mixture comprises 40 to 60% by weight of (a1), 10 to 30% by weight of (a2), 10 to 40% by weight of (a3) By weight based on the total weight of the pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition according to claim 1, wherein the copolymer has a viscosity at 25 ° C of 1600 to 8000 cPs. The pressure-sensitive adhesive composition according to claim 1, wherein the copolymer has a weight-average molecular weight of 1 million to 3 million g / mol. delete delete The pressure-sensitive adhesive composition according to claim 1, wherein the epoxy compound comprises at least one of the following structural formulas (1a) to (1e):
<Formula 1a>

&Lt; EMI ID =

&Lt; Formula 1c &gt;

<Formula 1d>

<Formula 1e>

. 2. The pressure-sensitive adhesive composition of claim 1, wherein the initiator comprises a mixture of a photo-radical initiator and a photo-cation initiator. 12. The composition of claim 11, wherein the composition is based on solids
100 parts by weight of the alicyclic group-containing (meth) acrylic copolymer,
With respect to 100 parts by weight of the alicyclic group-containing (meth) acrylic copolymer
5 to 35 parts by weight of the epoxy compound,
0.01 to 3 parts by weight of the photo radical initiator,
0.01 to 1 part by weight of the crosslinking agent,
With respect to 100 parts by weight of the epoxy compound
0.01 to 3 parts by weight of the photo cationic initiator
Sensitive adhesive composition. The pressure-sensitive adhesive composition according to claim 1, wherein the pressure-sensitive adhesive composition further comprises an epoxy-based silane coupling agent. 14. The pressure-sensitive adhesive composition according to claim 13, wherein the epoxy silane coupling agent is an oligomeric siloxane. delete A pressure-sensitive adhesive film formed by curing a pressure-sensitive adhesive composition according to any one of claims 1, 3 to 7, 10 to 14. The pressure-sensitive adhesive film according to claim 16, wherein the pressure-sensitive adhesive film is prepared by coating the pressure-sensitive adhesive composition on a release film and curing the pressure-sensitive adhesive composition or coating the pressure- Optical film; And
The optical display device according to claim 16, which is attached to one side or both sides of the optical film. The optical film according to claim 18, wherein the optical film comprises at least one of a touch panel, a window, 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, Film, surface protection film, plastic LCD substrate, indium tin oxide (ITO), fluorinated tin oxide (FTO), aluminum doped zinc oxide (AZO), carbon nanotube film, Ag nanowire- An optical display device comprising a graphene.

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