WO2015080346A1 - Adhesive composition, adhesive film formed therefrom, and optical display device comprising same - Google Patents

Abstract

The present invention relates to: an adhesive composition containing a (meth)acrylic-based copolymer containing an alicyclic group, an epoxy-based compound, an initiator and a cross-linking agent, wherein the content of the epoxy-based compound is approximately 5-35 parts by weight on the basis of 100 parts by weight of the (meth)acrylic-based copolymer containing an alicyclic group; an adhesive film comprising the same; and an optical display device comprising the same.

Description

Pressure-sensitive adhesive composition, pressure-sensitive adhesive film formed therefrom and optical display device comprising the same

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

Optical clear adhesive (OCA) film is an adhesive film used for interlayer adhesion or the touch screen attachment of cellular phones for laminating components in optical displays. In particular, the capacitive touchpad of the optical display device is attached to the window or the film by an adhesive film to detect a change in capacitance of the window or the film. In the touchpad, the adhesive film is laminated between the window glass and the TSP (touch screen panel) sensor glass. OCA film transmits more than 97% of light and functions as glass, but it has the advantage of improving the screen clarity and adhesiveness compared to the conventional double-sided tape. OCA film can be used not only for mobile phones but also for tablet PCs and TVs with medium and large display screens.

An object of the present invention is to provide a pressure-sensitive adhesive film that has good step filling capability, good durability reliability, and can be free of bubbles in the lamination process.

Another object of the present invention is to provide a pressure-sensitive adhesive composition capable of improving durability, cutting properties, embedding characteristics, and minimizing an increase in ITO resistance while satisfying a low dielectric constant (dielectric constant of 3.5 or less).

Still another object of the present invention is to provide a pressure-sensitive adhesive composition capable of simultaneously increasing cationic polymerization and radical polymerization to improve the crosslinked structure of the pressure-sensitive adhesive, thereby reducing the decrease in storage modulus even at high temperatures and increasing the reactivity of the silane.

Still another object of the present invention is to provide a pressure-sensitive adhesive composition in which end lift, bubble, warpage, etc. due to outgassing do not occur.

The pressure-sensitive adhesive composition of the present invention includes an alicyclic group-containing (meth) acrylic copolymer, an epoxy compound, an initiator, and a crosslinking agent, and the epoxy compound is about 5 to 35 to 100 parts by weight of the alicyclic group-containing (meth) acrylic copolymer. It may be included in parts by weight.

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

The optical display device of the present invention may include the adhesive film.

The present invention provides a pressure-sensitive adhesive film that has good step filling ability, good durability, and no bubble generation in the lamination process. The present invention provides a pressure-sensitive adhesive composition that can improve durability, cutting properties, embedding characteristics, and minimize an increase in ITO resistance while satisfying a low dielectric constant (dielectric constant of 3.5 or less). The present invention improves the crosslinked structure of the pressure-sensitive adhesive by simultaneously causing cationic polymerization and radical polymerization, thereby providing a pressure-sensitive adhesive composition having a low rate of decrease in storage modulus even 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 lifting, bubbles, warpage, etc. due to outgassing.

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

DETAILED DESCRIPTION Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification. In the present specification, '(meth) acrylate' means acrylate and (meth) acrylate, and 'top' and 'bottom' are defined on the basis of the drawings, and 'top' is 'bottom' according to the viewpoint. Bottom 'may be changed to' top '.

The pressure-sensitive adhesive composition of one embodiment of the present invention includes an alicyclic group-containing (meth) acrylic copolymer, an epoxy compound, an initiator, and a crosslinking agent, and the epoxy compound is about 5 to 100 parts by weight based on 100 parts by weight of the alicyclic group-containing (meth) acrylic copolymer. It may be included in 35 parts by weight. If the epoxy-based compound is included in less than 5 parts by weight bubbles may occur when the film is laminated, if more than 35 parts by weight may be poor durability and reliability. Specifically, the epoxy compound may be included in an amount of about 10 to 30 parts by weight based on 100 parts by weight of the alicyclic group-containing (meth) acrylic copolymer.

The alicyclic group-containing (meth) acrylic copolymer comprises a monomer mixture comprising an alkyl (meth) acrylate having an alkyl group of (a1) C7-C20, (a2) an alicyclic containing (meth) acrylate and a monomer containing a hydroxyl group (a3) It may be a copolymer of.

Alkyl (meth) acrylates having an alkyl group of C7-C20 may comprise a (meth) acrylic acid ester having an alkyl group of linear or branched unsubstituted C7-C20. For example, ethylhexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (Meth) acrylates, and the like, but are not necessarily limited thereto, and these may be applied alone or by mixing two or more kinds. Preferably, by using an alkyl (meth) acrylate having an alkyl group of C7-C10 may have the effect of increasing the initial adhesive force and the wettability to the substrate.

Alkyl (meth) acrylate having an alkyl group of C7-C20 is about 40 to 65% by weight of the monomer mixture or (meth) acrylic copolymer, specifically about 45 to 60% by weight, for example about 45,46,47 , 48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65% by weight, in the above range under heat and moisture resistance conditions No bubbles or lifting occurs, and may have excellent adhesion and excellent durability.

Alicyclic containing (meth) acrylate is C3-C20 alicyclic containing (meth) acrylate of C3-C10, for example. For example, there is isobornyl (meth) acrylate, bornyl (meth) acrylate, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, and the like, but are not necessarily limited to these alone or It can be applied by mixing two or more kinds. Preferably, by using a cycloaliphatic containing (meth) acrylate of C10-C15 may have the effect of increasing durability.

The alicyclic containing (meth) acrylate is about 10 to 30% by weight of the monomer mixture or (meth) acrylic copolymer, specifically about 15 to 25% by weight, for example about 15,16,17,18,19, 20, 21, 22, 23, 24, 25% by weight may be included. In the above range, heat / durability may be increased and adhesion may be increased.

The hydroxyl group-containing monomer is 2-hydroxyethyl (meth) acrylate which has a hydroxyl group, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate , 6-hydroxyhexyl (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, chloro-2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate, etc. (Meth) acrylates containing a C1-C20 alkyl group or a C5-C20 cycloalkyl group having a hydroxyl group including; And C1-C10 unsaturated alcohols including allyl alcohol, and the like, but are not necessarily limited thereto, and these may be applied alone or in combination of two or more thereof. Preferably, by using a (meth) acrylate having an alkyl group of C 1 -C 5 having a hydroxyl group, there may be an effect of improving adhesion and increasing durability.

The hydroxyl group-containing monomer is about 10 to 40% by weight of the monomer mixture or (meth) acrylic copolymer, specifically about 15 to 25% by weight, for example about 15,16,17,18,19,20,21,22 It can be included in the range, 23, 24, 25% by weight and has a synergistic effect in the above range, excellent durability and does not generate bubbles in the humidity conditions.

The alicyclic group-containing (meth) acrylic copolymer may further lower the curing shrinkage rate by further including a heteroalicyclic group. Specifically, the (meth) acrylic copolymer having an alicyclic group and a heteroalicyclic group includes (a1) alkyl (meth) acrylate having an alkyl group of C7-C20, (a2) cycloaliphatic containing (meth) acrylate, (a3) It may be a copolymer of a monomer mixture containing a hydroxyl group-containing monomer and (a4) heteroalicyclic (meth) acrylate.

The heterocycloaliphatic containing (meth) acrylate may include a (meth) acrylic monomer having a monocyclic heteroalicyclic group having C 4 -C 6 having nitrogen, oxygen or sulfur. For example, it may contain (meth) acryloyl morpholine and the like.

The heterocycloaliphatic containing (meth) acrylate is about 0.1 to 10% by weight, specifically about 1 to 5% by weight, for example about 1,2,3,4,5% by weight in the monomer mixture or the (meth) acrylic copolymer It may be included as, the curing shrinkage in the above range may be low and good reliability.

The alicyclic group-containing (meth) acrylic copolymer may further include a carboxylic acid group, thereby improving durability and increasing adhesion to the substrate, thereby improving durability. Specifically, the (meth) acrylic copolymer having an alicyclic group and a carboxylic acid group includes an alkyl (meth) acrylate having an alkyl group of (a1) C7-C20, (a2) an alicyclic containing (meth) acrylate, and a (a3) hydroxyl group. It may be a copolymer of a monomer mixture comprising a monomer and a monomer containing a (a5) carboxylic acid group.

The carboxylic acid group-containing monomer may be (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, and these may be applied alone or in combination of two or more kinds.

The monomer containing a carboxylic acid group may be included in 0-3% by weight of the monomer mixture or the (meth) acrylic copolymer. In the above range, the adhesion strength increase, the durability improvement effect, and the surface corrosion inhibition effect of the transparent electrode film may be expressed. Preferably about 0-2% by weight, more preferably about 0-1.5% by weight, most preferably about 0-1% by weight.

The (meth) acrylic copolymer may be polymerized together with the addition of other copolymerizable monomers in addition to the above-mentioned monomers. For example, it may be a (meth) acrylate having a pyrrolidoneyl group, a (meth) acrylate having a phosphate group, or the like.

The (meth) acrylic copolymer may have a glass transition temperature (Tg) of -35 ° C to -10 ° C, preferably -30 ° C to -13 ° C. It is excellent in workability in the said range, and excellent in durability and adhesive force.

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

The (meth) acrylic copolymer has a weight average molecular weight of 1 million to 3 million g / mol, preferably 1.5 million to 2.5 million g / mol, for example, 1.5 million, 1.6 million, 1.7 million, 1.8 million, and 1.9 million , 2 million, 2.1 million, 2.2 million, 2.3 million, 2.4 million and 2.5 million g / mol. In the above range, the adhesive composition may be cured to have durability even after being left for a long time under high temperature and high humidity conditions in manufacturing the adhesive film, and may have excellent adhesiveness.

The (meth) acrylic copolymer may be prepared by a conventional method. Specifically, it may be prepared by mixing the monomer mixture and the radical radical initiator and solution polymerization, suspension polymerization, photopolymerization, bulk polymerization, or emulsion polymerization. Specifically, solution polymerization may be performed at 50 to 100 ° C. by adding an optical radical initiator to the monomer mixture, and the optical radical initiator may be an acetophenone-based radical including 2,2-dimethoxy-2-phenylacetophenone and the like. A photoinitiator can be used. The photo radical initiator may be applied at about 0.01-3 parts by weight, preferably about 0.01-1 part by weight based on 100 parts by weight of the monomer mixture for preparing the (meth) acrylic copolymer. Low light leakage and excellent durability can be obtained in the above range.

The (meth) acrylic copolymer may be prepared by completely polymerizing the monomer mixture, or the polymerization may be completed after partial polymerization of the monomer mixture and further addition of an initiator and a crosslinking agent. Partial polymerization polymerizes the monomer mixture to polymerize until a 25 ° C. viscosity becomes a viscous liquid on the order of about 1,000-50,000 cPs, preferably about 1,000 to 6,000 cps, more preferably about 1,500 to 3,000 cps. The coating is easy in the viscosity range, there is an excellent workability.

The epoxy compound has two or more epoxy groups and is cured by a photo cationic initiator, which may be included in an adhesive film to increase 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 having one or more epoxy groups. In particular, by using together the (meth) acrylic-type copolymer which has an alicyclic group, and the epoxy type compound which has an alicyclic group, the effect of the adhesive film of this invention can be heightened further.

For example, the epoxy compound may be glycidyl such as tetramethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, bisphenol A diglycidyl ether, or a mixture thereof. Epoxy esters such as ethers, bisphenol A-diepoxy-acrylic acid adducts, and mixtures thereof, monomers and oligomers of alicyclic epoxy, cyclo aliphatic epoxy, mixtures thereof, and the like, but are not limited thereto. In addition, the alicyclic epoxy system may be, but is not limited to, the following Chemical Formula 1a to Chemical Formula 1e:

<Formula 1a>

<Formula 1b>

<Formula 1c>

<Formula 1d>

<Formula 1e>

.

.

The epoxy compound may be included in an amount of about 5 to 35 parts by weight, specifically about 10 to 30 parts by weight, based on 100 parts by weight of the (meth) acrylic copolymer, and no bubbles are generated when the film is laminated in the above range, and the reliability may be high. have.

The initiator may comprise one or more of an optical radical initiator, a photo cationic initiator, and may preferably comprise a mixture of an optical radical initiator and a photo cationic initiator. The photo radical initiator cures the (meth) acrylic copolymer, and the photo cationic initiator cures the epoxy compound. Therefore, the cationic polymerization and the radical polymerization are simultaneously performed to improve the crosslinked structure of the pressure-sensitive adhesive, whereby the decrease in storage modulus is small even at high temperatures, and the reactivity of the silane can be increased.

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

The photo cationic initiator may use a conventional photo cationic initiator capable of carrying out a photocurable reaction. Examples include, but are not limited to, onium salts such as aromatic diazonium salts, aromatic iodine aluminum salts, aromatic sulfonium salts, iron-arene complexes, mixtures thereof, and the like. As a specific example of a cation, diaryl, such as diphenyl iodonium, 4-methoxy diphenyl iodonium, bis (4-methylphenyl) iodonium, bis (4-tert- butylphenyl) iodonium, bis (dodecylphenyl) iodonium, etc. Triarylsulfonium such as iodonium, triphenylsulfonium, diphenyl-4-thiophenoxyphenylsulfonium, bis [4- (diphenylsulfonio) -phenyl] sulphide, bis [4- (di (4- (2-hydroxyethyl) phenyl) sulfonio) -phenyl] sulfide, η5-2,4- (cyclopentadienyl) [1,2,3,4,5,6-η]- (Methylethyl) -benzene] -iron (1+) etc. are mentioned. Specific examples of the anionic examples include borate (BF ₄ ^-) tetrafluoroborate, phosphate (PF ₆ ^-) hexafluoropropane, antimonate hexafluorophosphate (SbF ₆ ^-), are Senate hexafluorophosphate (AsF ₆ ^-), hexamethylene Chloro antimonate (SbCl ₆ ⁻ ) and the like. The photo cationic initiator may be included in an amount of about 0.01 to 3 parts by weight, preferably about 0.5 to 1.5 parts by weight, based on 100 parts by weight of the epoxy compound, and the polymerization of the epoxy compound may be sufficiently performed in the above range and the remaining amount of the initiator remains. Can be prevented.

The crosslinking agent may be preferably a polyfunctional (meth) acrylate capable of curing with an active energy ray. In embodiments, the polyfunctional (meth) acrylates include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentylglycol di (meth) acrylate, polyethylene glycol Di (meth) acrylate, neopentylglycol adipate di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, Ethylene oxide modified di (meth) acrylate, di (meth) acryloxy ethyl isocyanurate, allylated cyclohexyl di (meth) acrylate, tricyclodecanedimethanol (meth) acrylate, dimethylol dicyclopentane 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; Trimethylolpropane tri (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) acryloxyethyl isocyanurate; Tetrafunctional acrylates such as diglycerin tetra (meth) acrylate or pentaerythritol tetra (meth) acrylate; 5-functional acrylates, such as dipentaerythritol penta (meth) acrylate; And dipentaerythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate or urethane (meth) acrylate (ex. Isocyanate monomers and trimethylolpropane tri (meth) acrylate 6-functional acrylates such as reactants, etc., but are not limited thereto.They may be used alone or in combination of two or more thereof. Preferably, the polyfunctional (meth) of polyhydric alcohol having 2-20 hydroxyl groups ) Acrylates.

The crosslinking agent may be included in an amount of about 0.01 to 1 part by weight, specifically about 0.05 to 1 part by weight, specifically about 0.1 to 1 part by weight, based on 100 parts by weight of the (meth) acrylic copolymer, and the effects of the pressure-sensitive adhesive film of the present invention in the above range. May appear.

In addition, conventional isocyanate-based, epoxy-based, aziridine-based, melamine-based, amine-based, imide-based, carbodiimide-based, amide-based crosslinking agents, or a combination thereof may be used.

In an embodiment, the pressure-sensitive adhesive composition is about 5 to 35 parts by weight of an epoxy compound, about 0.01 to 3 parts by weight of an optical radical initiator, about 0.01 to 1 part by weight of a crosslinking agent, and epoxy based on 100 parts by weight of the (meth) acrylic copolymer on a solids basis. It may include about 0.01 to 3 parts by weight of the photo cationic initiator based on 100 parts by weight of the system compound, there may be no problems such as step filling, durability, no bubbles, outgas generation.

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, a tackifying resin, a modified resin (polyol resin, Phenolic resins, acrylic resins, polyester resins, polyolefin resins, epoxy resins, epoxidized polybutadiene resins, etc.), leveling agents, antifoaming agents, plasticizers, dyes, pigments (such as colored pigments, extender pigments), treatment agents, sunscreen agents, Conventional additives such as fluorescent brighteners, dispersants, thermal stabilizers, light stabilizers, ultraviolet absorbers, antistatic agents, lubricants and solvents may be further included.

The silane coupling agent may further include an epoxy group-containing silane coupling agent, but is not limited thereto. The epoxy group-containing silane coupling agent may improve the adhesion and adhesion stability between the pressure-sensitive adhesive and the glass substrate to improve heat resistance and moisture resistance, and to improve adhesion reliability even when the adhesive is left for a long time under high temperature and / or high humidity conditions. It can be. Moreover, in the pressure-sensitive adhesive composition of the present invention, radical polymerization and cationic polymerization may occur at the same time, so that the reactivity of the silane (silane-based coupling agent) may be increased. The epoxy group-containing silane coupling agent may be included in an amount of about 0.1 to 30 parts by weight based on 100 parts by weight of the (meth) acrylic copolymer.

In an embodiment, an oligomeric siloxane represented by the following formula (1) may be used as the epoxy group-containing silane coupling agent. By using an oligomeric siloxane, the effect of this invention can be heightened further.

[Formula 1]

In Formula 1, 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 3-25 and m is an integer of 1-10. Preferably R ₁ , R ₂ and R ₃ may be methyl, ethyl or propyl groups.

The oligomeric siloxane may have a viscosity of 25 ° C. of about 15 to 40 cps, preferably 20 to 35 cps. In the above range, the coating property may be good.

The oligomeric siloxane may have a refractive index of about 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 in the molecule of about 30 to 60 weight percent, preferably about 35 to 55 weight percent. It has excellent durability, adhesion and reworkability in the above range.

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

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

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

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

In one embodiment, the pressure-sensitive adhesive film may include the pressure-sensitive adhesive composition. For example, the pressure-sensitive adhesive composition may be prepared by coating and drying a release film (eg, polyester, polyethylene terephthalate film). The pressure-sensitive adhesive film is a state in which the curing of the pressure-sensitive adhesive composition is not completely, and may include the (meth) acrylic copolymer, an epoxy compound, an initiator, a crosslinking agent and the like. In another embodiment, the pressure-sensitive adhesive film may include a cured product of the pressure-sensitive adhesive composition. For example, the pressure-sensitive adhesive composition may be UV cured after coating on a release film (eg, polyester, polyethylene terephthalate film). UV curing may be performed at conditions of about 0.1-40 mW / cm ² , about 1-5 minutes. Preferably, it can be cured in a state where oxygen is blocked.

The coating thickness is not particularly limited, and may be about 50 μm to 2 mm, preferably about 50 μm to 1.5 mm, and the final adhesive film may be used in the optical display device.

Although the thickness (thickness except a release film) of an adhesive film is not specifically limited, It may be about 10 micrometers-2 mm, Preferably it is about 100 micrometers-1.5 mm, It can be used for an optical display apparatus in the said range.

The adhesive film may be used as an optical clear adhesive (OCA) film or a touch panel film.

The pressure-sensitive adhesive film was laminated at a thickness of 1 mm or more, and the dielectric constant measured under the conditions of 400 kHz using an LCR meter (manufacturer: agilent product name: E4980A) was about 3.5 or less, preferably about 3.5 to 3.0, In the above range, the reliability and touch sensitivity are excellent.

The pressure-sensitive adhesive film has a resistance change ratio (ΔR) represented by Equation 1 below about 0 to less than 5%, preferably greater than about 0 to less than 4%, more preferably about 0 to 3%, and optical display within the above range. It can be used in the device.

[Equation 1]

(In Equation 1, P ₂ is the resistance after leaving the adhesive film at 60 ℃ / 90% relative humidity for 240 hours, P ₁ is the initial resistance of the adhesive film.)

The adhesive film may have a storage modulus of about 1 × 10 ⁵ to 5 × 10 ⁷ dyne / cm ² at 30 ° C., preferably about 1 × 10 ⁶ to 5 × 10 ⁷ dyne / cm ² , and a storage modulus at 80 ° C. About 1 × 10 ⁴ to 2 × 10 ⁶ dyne / cm ² , preferably about 9 × 10 ⁴ to 1 × 10 ⁶ dyne / cm ² . The cross-linked structure of the adhesive film is excellent in the above range, it is possible to prevent the generation of micro bubbles due to outgassing, such as PC Sheet, PC Film. The storage modulus was measured using an ARES (Advanced Reometric Expansion System) (manufacturer: TA) by performing a frequency sweep test (frequency: 1 Hz reference) at a temperature of 30 ℃ and 80 ℃.

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

An optical display device according to an embodiment of the present invention may include an adhesive film according to an embodiment of the present invention. Specifically, the optical display device is an optical film; And an adhesive film attached to one or both surfaces of the optical film, and the adhesive film may include the adhesive film of one embodiment of the present invention.

Optical films include touch panels, windows, polarizing plates, color filters, retardation films, elliptical polarizing films, reflective films, antireflection films, compensation films, brightness enhancement films, alignment films, light diffusion films, glass scattering prevention films, surface protection films, Transparent electrode films such as plastic LCD substrates, indium tin oxide (ITO), fluorinated tin oxide (FTO), aluminum dopped zinc oxide (AZO), carbon nanotube (CNT), Ag nanowire, and graphene Can be mentioned. The manufacturing method of the optical film can be easily manufactured by those skilled in the art to which the present invention pertains.

1 is a cross-sectional view of an organic light emitting diode display according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the organic light emitting diode display 100 includes a substrate 10, an encapsulation layer 20 encapsulating the OLED element 15, an OLED element 15 formed on the substrate 10, and encapsulation. The first adhesive film 25 formed on the layer 20, the first transparent conductive layer 40 and the substrate 35 formed on the substrate 35, the substrate 35, and formed on the first adhesive film 25. ), A transparent conductor including a second transparent conductive layer 30 formed below, a polarizing plate 45 formed on the first transparent conductive layer 40, and a second adhesive film 50 formed on the polarizing plate 45. , May include a window 55 formed on an upper portion 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 an embodiment of the present invention. Can be.

The substrate 10 may be a substrate (eg, a TFT substrate) commonly used in an organic light emitting diode display, and specifically, may be a glass substrate, a polyimide of a plastic material, an epoxy, an acrylic, a silicon substrate, or the like. It may be a substrate having flexibility.

The device for OLED 15 is commonly used in an organic light emitting display device, and although not shown in FIG. 1, includes an organic light emitting film formed between a first electrode, a second electrode, and a first electrode and a second electrode. The organic light emitting layer may be formed by sequentially stacking a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer, but is not limited thereto.

The encapsulation layer 20 may be formed of an inorganic, organic or inorganic / organic mixture by protecting the OLED element 15 from external moisture or oxygen.

The transparent conductor is conductive to generate an electrical signal with respect to the stimulus from the outside, and includes a substrate 35, a first transparent conductive layer 40 and a second transparent conductive layer 30 formed on both surfaces of the substrate 35. can do. The substrate 35 may be an optically transparent film (eg, a polyester including polycarbonate, polyethylene terephthalate, etc.) or a glass plate, and the first transparent conductive layer 40 and the second transparent conductive layer 30 may be the same or different. It may be, but is not limited to a transparent conductive film having conductivity, it may be an indium tin oxide (ITO) film, or a film containing a metal nanowire, although not shown in Figure 1, the first transparent conductive layer 40, and / Alternatively, the second transparent conductive layer 30 may be patterned.

The first adhesive film 25 adheres the encapsulation 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. The same or different, and may include the adhesive film of an embodiment of the present invention, but is not limited thereto.

The polarizer 45 may serve as an anti-reflection in the organic light emitting display, and may include a polarizer, a protective film and / or a retardation film formed on the polarizer, although not shown in FIG.

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

For example, the touch panel may be attached to a window or an optical film by using the adhesive film on the touch pad. Or it may be applied as a pressure-sensitive adhesive film to a conventional polarizing film as in the prior art.

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

(A) Monomer for (meth) acrylic copolymers: EHA (2-ethylhexyl acrylate), IBOA (isobornyl acrylate), HEA (2-hydroxyethyl acrylate), ACMO (acryloyl morpholine)

(B) Epoxy compound: CY179 (manufacturer: HuntSman) of formula 1a

<Equation 1a>

(C) Initiator: (C1) Photo radical initiator: Irgacure 651 (2,2-dimethoxy-2-phenylacetophenone) (Ciba Japan K.K.), (C2) Photo cationic initiator: CPI210S (manufacturer: Maternal child Pro)

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

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

Example 1

50 parts by weight of ethylhexyl acrylate (EHA), 25 parts by weight of isobornyl acrylate (IBOA), 25 parts by weight of hydroxy ethyl acrylate (HEA), and 2,2-dimethoxy-2-phenyl as an optical radical initiator A mixture was prepared by mixing 0.04 parts by weight of acetophenone (product name: Irgacure ™ 651, manufactured by Ciba Japan) in a glass container. After replacing the dissolved oxygen with nitrogen gas, using a low pressure lamp (device name: sylvania Lamp BL360) irradiated with ultraviolet light to polymerize the mixture to obtain an alicyclic group-containing (meth) acrylic copolymer having a viscosity of about 1,500 cps It was. 0.1 weight part of 1,6-hexanediol diacrylate (HDDA) as a polyfunctional (meth) acrylate to the produced (meth) acrylic copolymer, an epoxy group-containing silane coupling agent (product name: KBM-403, manufacturer: Shinetsu ) 0.1 parts by weight and 0.16 parts by weight of 2,2-dimethoxy-2-phenylacetophenone (product name: Irgacure ™ 651, manufactured by Ciba Japan) as an optical radical initiator, were added and mixed, and the epoxy mixture (product name: CY179 , Manufacturer: Huntsman) 10 parts by weight and 0.15 parts by weight of the photo cationic initiator (product name: CPI210S, manufacturer: San Apro) to prepare a pressure-sensitive adhesive composition. The resulting pressure-sensitive adhesive composition was coated on a 50 μm thick polyester film (release film) to form an adhesive film with a thickness of 175 μm. In order to remove oxygen that adversely affects the polymerization, a 50 μm thick polyester film (release film) was covered on the adhesive film, and then a low pressure lamp (sylvania Lamp BL360) was used on both sides of the release film for about 3 minutes. By using a high-pressure metal halide lamp (manufacturer: litzen, device name: UV curing machine), a ultraviolet-ray (UV) of 1,500 mJ / cm ² at a UV intensity of 800 mW / cm ² was irradiated to prepare a transparent adhesive film.

Example 2

The same method as Example 1 except that an epoxy group-containing siloxane coupling agent (product name: X-41-1059A, manufacturer: Shinetsu) was used instead of the epoxy group-containing silane coupling agent (product name: KBM-403, manufacturer: Shinetsu). An adhesive composition and an adhesive film were prepared.

Examples 3 to 5

(A), 0.04 parts by mass (C1) of the contents described in Table 1 (unit: parts by weight) of 100 parts by weight of an ACMO, 58 parts by weight of EHA, 20 parts by weight of IBOA, and 20 parts by weight of HEA. The mixture was mixed well in a glass vessel, the dissolved oxygen was replaced with nitrogen gas, and the mixture was partially polymerized by irradiating ultraviolet light using a low pressure lamp for a few minutes to obtain a viscous liquid having a viscosity of about 1,500 cP. To the resulting composition, (E), the remaining amount of (C1), (D), (B), (C2) was added to the content described in Table 1 (unit: parts by weight) and then mixed to prepare a pressure-sensitive adhesive composition. .

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

In order to remove the oxygen that adversely affects the polymerization on the transparent adhesive sheet 1, after covering the release film, by irradiating a low-pressure lamp for about 3 minutes from the two surfaces of the release film comprising a pressure-sensitive adhesive film 2 of 175㎛ thickness The transparent adhesive sheet 2 was manufactured.

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

Comparative Example 1

Except that the cationic photoinitiator CPI210S and epoxy compound CY179 was not used in Example 1, an adhesive composition and an adhesive film were prepared in the same manner as in Example 1.

Comparative Example 2-3

Except for changing the content of the components of (A), (B), (C), (D), (E) in the Example as shown in Table 1, the same method was carried out, transparent adhesive sheets 1 and 2 Was prepared.

The physical properties of the adhesive films of Examples and Comparative Examples were evaluated and shown in Table 1.

(1) Bubble generation at lamination: The adhesive film 2 was laminated on the ITO film, autoclave, and then bubble generation was visually evaluated. When no bubbles occurred at all, it was evaluated as X, and when one or more bubbles were generated, it was evaluated as ○.

(2) Hardening shrinkage (%): The hardening shrinkage was calculated by measuring the specific gravity of the liquid composition before photocuring and the specific gravity of the solid after curing with DME-220E (Shinko, Japan). 5 g of the composition was coated in a thickness of about 10 μm ± 2 μm and then UV cured (100 mW / cm 2 X 10 seconds) with a metal halide lamp to prepare a film (thickness: 8 to 12 μm, width of 1.5 to 2.5 cm, length of 1.5 to 2.5 cm). It was performed by. The cure shrinkage rate can be calculated according to the following formula (1).

<Equation 1>

Cure Shrinkage (%) = [(Solid specific gravity after curing-specific gravity of liquid composition before curing)] / Specific gravity of liquid composition before curing x 100

(3) Resistance change rate (ΔR,%): Adhesion film 2 was attached to ITO PET, and electrodes were formed using silver paste on both sides to prepare a sample. Thereafter, the initial resistance (P ₁ ) was measured for the prepared sample, and the sample was left for 60 hours at 60 ° C./90% relative humidity, and then the resistance (P ₂ ) was measured. The resistance was measured using a Checkman portable resistance, voltage, and current meter (manufacturer: Taekwang Electronics). Then, the resistance change rate (ΔR,%) was measured by substituting the resistance value measured under each condition as follows.

<Equation 1>

(In the above, P ₂ is the resistance after being left for 240 hours in the condition of 60 ℃ / 90% relative humidity, P ₁ is the initial resistance)

(4) Reliability: After bonding PC film / ITO film / Glass and PET film, it is allowed to stand at 60 ° C / 90% relative humidity for 500 hours, then visually check whether the surface is lifted or peeled off or bubbles are generated. Observation was carried out by the following criteria.

<Evaluation Criteria>

○: Good (no bubble or peeling phenomenon)

△: Good (some bubbles or peeling phenomenon)

X: Poor (a lot of bubbles and peeling phenomenon)

(5) Peeling strength (gf / 25 mm): Using a 50 μm thick PET film (backing film), the prepared adhesive film is attached to the ITO film, 30 minutes after the attachment of the Texture Analyzer : TA.XT_Plus, manufacturer: Stable Micro System), the peel force was measured at 300mm / min speed.

Example 3 to Example 5 attached to ITO and irradiated 2000mj to the metal halide lamp and after 30 minutes was measured the peel force in the same manner.

(6) Durability: After bonding PC film / ITO film / Glass and PET film, it is allowed to stand at 60 ℃ / 90% relative humidity for 500 hours. Observation was carried out by the following criteria.

<Evaluation Criteria>

○: Good (no bubble or peeling phenomenon)

△: Good (some bubbles or peeling phenomenon)

X: Poor (a lot of bubbles and peeling phenomenon)

(7) Dielectric constant: It measured on the conditions of 400 kHz using the LCR meter (manufacturer: agilent product name: E4980A). The pressure-sensitive adhesive was prepared by measuring 1mm.

(8) Storage modulus (dyne / cm ² ): Frequency sweep test (frequency: 1 Hz) at temperatures of 30 ° C. and 80 ° C. using ARES (Advanced Reometric Expansion System) (manufacturer: TA) ) Was measured.

Table 1 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 photoinitiators 0.2 0.2 0.3 0.3 0.3 0.2 0.3 0.3 Cationic photoinitiator 0.15 0.15 0.1 0.2 0.3 - 0.5 0 Crosslinking 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 occurrence at lamination X X X X X X X O Curing Shrinkage (%) - - Within 0.1% Within 0.1% Within 0.1% - Within 0.1% Within 0.1% % 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 modulus (30 ℃) 1.2 x 10 ⁷ 1.2 x 10 ⁷ 1.3 x 10 ⁷ 2.3 x 10 ⁷ 3 x 10 ^{7 6} x 10 ⁶ 5 x 10 ⁷ 3.5 x 10 ⁶ Storage modulus (80 ℃) 2.3 x 10 ⁶ 2.3 x 10 ⁶ 2.3 x 10 ⁶ 3.4 x 10 ⁶ 4 x 10 ⁶ 2.1 x 10 ⁴ 5 x 10 ⁶ 4 x 10 ⁵

As shown in Table 1, the pressure-sensitive adhesive film of the present invention has no problem of bubble generation when laminated, and the durability was good. On the other hand, in the comparative example, bubbles or lifting occurred due to the outgassing of the PC which was not surface-treated under the reliability conditions.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (19)

Alicyclic group-containing (meth) acrylic copolymer, Epoxy compounds, Initiator, and Including a crosslinking agent, The epoxy compound is an adhesive composition containing about 5 to 35 parts by weight based on 100 parts by weight of the alicyclic group-containing (meth) acrylic copolymer. The monomer mixture of claim 1, wherein the copolymer comprises an alkyl (meth) acrylate having an alkyl group of (a1) C7-C20, (a2) cycloaliphatic containing (meth) acrylate, and (a3) hydroxyl-containing monomer. Adhesive composition containing the copolymer of. The pressure-sensitive adhesive composition of claim 2, wherein the monomer mixture comprises about 40-60 wt% of (a1), about 10-30 wt% of (a2), and about 10-40 wt% of (a3) on a solids basis. . The pressure-sensitive adhesive composition of claim 2, wherein the monomer mixture further comprises (a4) heteroalicyclic containing (meth) acrylate. The method of claim 4, wherein the monomer mixture is based on solids, based on solids, (a1) about 40-60% by weight, (a2) about 10-30% by weight, (a3) about 10-40% by weight, (a4) Pressure-sensitive adhesive composition comprising about 0.1-10% by weight. The pressure-sensitive adhesive composition of claim 1, wherein the copolymer has a viscosity of about 1600 to 8000 cPs at 25 ° C. The pressure-sensitive adhesive composition of claim 1, wherein the copolymer has a weight average molecular weight of about 1 million to 3 million g / mol. The pressure-sensitive adhesive composition of claim 1, wherein the epoxy compound comprises two or more epoxy groups. The method of claim 1, wherein the epoxy-based compound is a glycol containing one or more of tetramethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, bisphenol A diglycidyl ether Cyl ether; Epoxy esters containing bisphenol A-diepoxy-acrylic acid adducts; Monomers of alicyclic epoxy or oligomers thereof; And at least one of cyclo aliphatic epoxy. The pressure-sensitive adhesive composition of claim 1, wherein the epoxy compound comprises at least one of Formulas 1a to 1e: <Formula 1a>

<Formula 1b>

<Formula 1c>

<Formula 1d>

<Formula 1e>

. The pressure-sensitive adhesive composition of claim 1, wherein the initiator comprises a mixture of an optical radical initiator and a photo cationic initiator. The composition of claim 11, wherein the composition is on a solids basis 100 parts by weight of the alicyclic group-containing (meth) acrylic copolymer, To 100 parts by weight of the alicyclic group-containing (meth) acrylic copolymer About 5 to 35 parts by weight of the epoxy compound, About 0.01 to 3 parts by weight of the optical radical initiator, About 0.01 to 1 part by weight of the crosslinking agent, 100 parts by weight of the epoxy compound About 0.01 to 3 parts by weight of the photocationic initiator Pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition of claim 1, wherein the pressure-sensitive adhesive composition further comprises an epoxy-based silane coupling agent. The pressure-sensitive adhesive composition of claim 13, wherein the epoxy silane coupling agent is an oligomeric siloxane. The pressure-sensitive adhesive composition of claim 1, wherein the dielectric constant of the pressure-sensitive adhesive film cured the pressure-sensitive adhesive composition is about 3.5 or less. The pressure-sensitive adhesive film formed by curing the pressure-sensitive adhesive composition according to any one of claims 1 to 15. The pressure-sensitive adhesive film of claim 16, wherein the pressure-sensitive adhesive film is prepared by coating the pressure-sensitive adhesive composition on a release film to cure or curing the pressure-sensitive adhesive composition on a conductive film. Optical film; And An optical display device comprising the adhesive film of claim 16 attached to one or both surfaces of the optical film. The method of claim 18, wherein the optical film is a touch panel, a window, a polarizing plate, a color filter, a retardation film, an elliptical polarizing film, a reflective film, an antireflection film, a compensation film, a brightness enhancement film, an alignment film, a light diffusion film, glass scattering prevention Films, surface protective films, plastic LCD substrates, indium tin oxide (ITO), fluorinated tin oxide (FTO), aluminum dopped zinc oxide (AZO), films with carbon nanotube (CNT), films with Ag nanowires or yes Optical display device comprising a pin (graphene).

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