KR20140046366A - Adhesive film, adhesive composition for the same and display member comprising the same - Google Patents

Abstract

The present invention relates to: an adhesive film which contains a hardened material of a (meth)acrylate copolymer, and has a refractive index of 1.5-1.6; an adhesive composition for the same; and a display member comprising the same. The (meth)acrylate copolymer is a (meth)acrylate copolymer of a monomer mixture which contains 20 wt% or more monomers with two or more aromatic groups.

Description

Adhesive film, pressure-sensitive adhesive composition for this, and display member including the same {ADHESIVE FILM, ADHESIVE COMPOSITION FOR THE SAME AND DISPLAY MEMBER COMPRISING THE SAME}

The present invention relates to an adhesive film, a pressure-sensitive adhesive composition therefor and a display member comprising the same. More specifically, the present invention has a high refractive index to solve the problem of pattern visibility, excellent durability and peel strength, there is no yellowing, relates to an adhesive film, a pressure-sensitive adhesive composition for this and a display member comprising the same.

The capacitive touch pad is attached to a window or film positioned on an upper surface and a light-transparent adhesive film, and exhibits characteristics by detecting a change in capacitance in the window or film. Glass, PMMA, PC, etc. may be used as the window. Depending on the type of window material, problems such as lifting, bubble generation, warpage, and ITO patterns may occur when the environment changes. In addition, when using a material such as CNT, Ag nanowires, graphene (graphene), etc. that is an ITO replacement material, there is a problem that the pattern is recognized due to the difference in refractive index. Particularly, in the case of Ag nanowires and CNTs, there is a problem in that the pattern of the touch panel is visually recognized due to the difference in refractive index when the touch module is manufactured.

On the other hand, in the conventional polymerization of the (meth) acrylic copolymer included in the production of the OCA film in the conventional solution polymerization, when the monomer has an aromatic group (meth) acrylic copolymer was capable of yellowing and the reaction rate could be slow.

Accordingly, there is a demand for development of an adhesive film capable of solving the pattern visibility problem at high refractive index while having excellent durability and peel strength.

In this regard, Japanese Laid-Open Patent Publication No. 2009-030043 discloses an acrylic copolymer (A) containing 20 to 95% by weight of structural units derived from benzyl (meth) acrylate, an epoxy-based thermosetting resin (B), and The adhesive composition containing a hardening | curing agent (C) is disclosed. However, there is a limit in solving the pattern visibility problem by increasing the refractive index.

An object of the present invention is to provide a pressure-sensitive adhesive film having a high refractive index can solve the pattern visibility problem, excellent durability and peel strength, no yellowing.

Another object of the present invention is to provide a pressure-sensitive adhesive composition comprising a (meth) acrylic copolymer prepared by polymerization with a fast reaction rate.

Still another object of the present invention is to provide a display member including the adhesive film.

The pressure-sensitive adhesive film of one aspect of the present invention includes a cured product of the (meth) acrylic copolymer-containing composition, and the refractive index may be 1.5 to 1.6.

The adhesive composition which is another aspect of this invention may contain the (meth) acrylic-type copolymer of the monomer mixture containing 20 weight% or more of monomers which have two or more aromatic groups.

Another aspect of the present invention, the display member may include the adhesive film.

The present invention has a high refractive index can solve the problem of pattern visibility, has excellent durability, peel strength, and provided a pressure-sensitive adhesive film without the occurrence of yellowing. In addition, the present invention provides a pressure-sensitive adhesive composition comprising a (meth) acrylic copolymer prepared by polymerization with a fast reaction rate.

1 is a sectional view of a display member according to one embodiment of the present invention.

In the present specification, "(meth) acrylate" may mean acrylate and methacrylate, and "(meth) acrylic" may mean acryl or methacryl.

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

As used herein, "substituted" in "substituted or unsubstituted" means that one or more hydrogen atoms constituting the functional group is halogen (F, Cl, Br or I), hydroxy group, nitro group, cyano group, carboxylic acid group, 1-20 carbon atoms It may mean an alkyl group, an aryl group having 6 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, a heteroaryl group having 3 to 30 carbon atoms, or a heterocycloalkyl group having 2 to 30 carbon atoms.

The adhesive film which is one aspect of this invention contains the hardened | cured material of a (meth) acrylic-type copolymer containing composition, and refractive index can be 1.5 or more, for example, 1.5-1.6, Preferably it is 1.51-1.53.

The adhesive film is an optical clear adhesive (OCA) film, and may be used, for example, to adhere a window or film of glass, PMMA (polymethylmethacrylate) or PC (polycarbonate) to a touch panel.

The pressure-sensitive adhesive film is an OCA film, and has a higher refractive index than the conventional OCA film, so that the pattern hiding power is high, thereby solving the problem of the pattern of the transparent electrode film being visually recognized.

The said refractive index can be measured by a conventional method. For example, it can measure with the ASTM D1218 method about the adhesion film of 10 micrometers-2 mm in thickness.

The adhesive film may have a dielectric constant average value of less than three. In the above range, there may be a pattern visibility prevention effect. Preferably, the dielectric constant average value may be 2.8 to 2.9.

The adhesive film may be used as an OCA film or a touch panel film.

The thickness (thickness except for the release film) of the adhesive film is not particularly limited, but may be 10 μm to 2 mm, preferably 100 μm to 1.5 mm.

The pressure-sensitive adhesive film may include a cured product of the pressure-sensitive adhesive composition containing the (meth) acrylic copolymer. In an embodiment, the pressure-sensitive adhesive film may be prepared by coating the pressure-sensitive adhesive composition on a release film (eg, polyester, polyethylene terephthalate film) and then UV curing.

In an embodiment, UV curing can be performed at conditions of 50 mW / cm ² or less, 6 minutes or less. Preferably, it can be cured in a state where oxygen is blocked. The coating thickness is not particularly limited and may be 50 μm to 2 mm, preferably 50 μm to 1.5 mm.

Hereinafter, the pressure-sensitive adhesive composition will be described in detail.

The (meth) acrylic copolymer may include a (meth) acrylic copolymer of a monomer mixture containing 20% by weight or more of a monomer having two or more aromatic groups.

The (meth) acrylic copolymer may include 10 wt% or more, preferably 15 to 35 wt% of the functional group of Formula 1 below:

≪ Formula 1 >

(In the above, Y ₁ is one or more substituents selected from the group consisting of a substituted or unsubstituted phenoxy group, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and a substituted or unsubstituted arylalkyl group having 7 to 21 carbon atoms. An aryl group having 6 to 20 carbon atoms,

X ₁ is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted -R- (CH ₂ ) _n- (wherein R is O, S, NH or NR '(R' is Hydrogen or an alkyl group having 1-5 carbon atoms, n is an integer of 1-10),

* Is a linking group to a molecule).

The aliphatic hydrocarbon group may be a linear or branched alkylene group or an alkyl group.

The copolymer may further include at least one of an alkyl group, a hydroxyl group, an alicyclic group, and a carboxylic acid group, in addition to the functional group of Chemical Formula 1.

( Meta Acrylic Copolymer

The (meth) acrylic copolymer is an air of a monomer mixture including an alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms, an alicyclic containing (meth) acrylate, a monomer containing a hydroxyl group, and a monomer having two or more aromatic groups. It may be coalescing.

The monomer mixture may further include a monomer including a carboxylic acid group.

The alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms may include a (meth) acrylic acid ester having a linear or branched alkyl group having 1 to 20 carbon atoms. For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, ethylhexyl (meth) ) Acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate May be, but is not necessarily limited thereto. The alkyl (meth) acrylates may be included alone or in combination of two or more.

Alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms may be included in 10 to 50% by weight of the monomer mixture or (meth) acrylic copolymer. In the above range, bubbles or lifting does not occur under heat and moisture resistant conditions, and may have excellent durability. Preferably 15 to 50% by weight, more preferably 45 to 50% by weight may be included.

The alicyclic containing (meth) acrylate may include an alicyclic group containing (meth) acrylate having 3 to 20 carbon atoms. For example, it may be one or more of isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, and cyclopentyl (meth) acrylate, but is not necessarily limited thereto. Alicyclic containing (meth) acrylate may be contained individually or in mixture of 2 or more types.

Alicyclic containing (meth) acrylate may be included in 1 to 30% by weight of the monomer mixture or (meth) acrylic copolymer. In the above range, heat / durability may be increased and adhesion may be increased. Preferably 1 to 15% by weight, more preferably 5 to 10% by weight may be included.

The hydroxyl group-containing monomer is 2-hydroxyethyl (meth) acrylate, 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, and the like (Meth) acrylates containing an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 5 to 20 carbon atoms having a hydroxyl group; And unsaturated alcohols having 1 to 10 carbon atoms including allyl alcohol, and the like, but are not necessarily limited thereto. The hydroxyl group-containing monomer may be included alone or in combination of two or more thereof.

The hydroxyl group-containing monomer may be included in 10 to 30% by weight of the monomer mixture or (meth) acrylic copolymer. There is a synergistic effect in the above range, excellent durability and no bubbles occur in the humidity conditions. Preferably it may be included in 15 to 25% by weight, more preferably 19 to 20% by weight.

The monomer having two or more aromatic groups may have a refractive index of 1.50 or more, preferably 1.50 to 1.60. In the above range, the adhesive film made of the pressure-sensitive adhesive composition can ensure a high refractive index.

The monomer having two or more aromatic groups may have two or more aromatic groups, for example, two to five.

The monomer having two or more aromatic groups may include a monomer of Formula 2, a fluorene monomer, a naphthalene monomer, a urethane monomer having two or more aromatic groups, a sulfur monomer having two or more aromatic groups, or a mixture thereof. :

(2)

(In the above, Y ₁ is one or more substituents selected from the group consisting of a substituted or unsubstituted phenoxy group, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and a substituted or unsubstituted arylalkyl group having 7 to 21 carbon atoms. An aryl group having 6 to 20 carbon atoms,

X ₁ is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted -R- (CH ₂ ) _n- (wherein R is O, S, NH or NR '(R' is Hydrogen or an alkyl group having 1-5 carbon atoms, n is an integer of 1-10),

R ₁ is hydrogen or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms)

Preferably, Formula 2 may have a structure of Formula 2-1:

≪ Formula (2-1)

(Wherein Z ₁ is a substituted or unsubstituted phenoxy group, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 21 carbon atoms,

m is an integer from 1-5,

X ₁ is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted -R- (CH ₂ ) _n- (wherein R is O, S, NH or NR '(R' is Hydrogen or an alkyl group having 1-5 carbon atoms, n is an integer of 1-10),

R ₁ is hydrogen or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms)

In the above, "-(CH ₂ ) _n- " in -R- (CH ₂ ) _n -of X ₁ may be linear or branched.

In the above, -R- (CH _{2) n} of X ₁ - in "-R-" is "Y ₁ -" of formula (1) is connected to.

Preferably, Z ₁ is a substituted or unsubstituted phenoxy group or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms.

Preferably, X ₁ is a substituted or unsubstituted alkylene group having 1-5 carbon atoms, or a substituted or unsubstituted -R- (CH ₂ ) _n- (wherein R is O, S, NH or NR '( R 'is hydrogen or an alkyl group having 1-5 carbon atoms, n is an integer of 1-5).

In an embodiment, the monomer of Formula 2 may be phenoxy benzyl acrylate of Formula 2a, phenyl phenoxy ethyl acrylate of Formula 2b, or a mixture thereof.

≪ EMI ID =

(2b)

The fluorene-based monomer may include a monomer derived from the monomer of Formula 3, or a monomer of Formula 4 below.

(3)

(In the above, Y ₂ , Y ₃ are each independently an acrylate group, methacrylate group, epoxy group or isocyanate group,

R ₂ and R ₃ are each independently a substituted or unsubstituted C 1-10 alkylene group, a substituted or unsubstituted C 2-10 alkenylene group, a substituted or unsubstituted C 2-10 alkynylene group, A substituted or unsubstituted arylene group having 6 to 20 carbon atoms, a substituted or unsubstituted heteroalkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted heteroarylene group having 5 to 20 carbon atoms,

X ₂ , X ₃ , X ₄ , X ₅ , X ₆ , X ₇ , X ₈ , X ₉ are the same or different, and each independently hydrogen, halogen, substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, substituted or Unsubstituted C 2-10 alkenyl group, substituted or unsubstituted C 2-10 alkynyl group, substituted or unsubstituted C 6-20 aryl group, substituted or unsubstituted C 1-10 alkoxy group, A substituted or unsubstituted heteroalkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted arylalkyl group having 7 to 20 carbon atoms, a substituted or unsubstituted amine group,

At least one of Y ₂ and Y ₃ is an acrylate group or a methacrylate group.

≪ Formula 4 >

(In the above, R is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a cycloalkyl group having 5 to 20 carbon atoms,

       m is an integer from 0-4,

       n is an integer of 1-5.)

Monofunctional acrylic acid or methacrylic acid may be esterified to the monomer of Formula 4 to prepare a monomer having acrylate or methacrylate.

In addition, the fluorene monomers are bisphenol-FLA (Bisphenol-FLA), bisphenol-FL (Bisphenol-FL), fluorenone (fluorenone), 2,7-dibromofluorenone (2,7-Dibromofluorenone), 9- Monofunctional acrylate or methacrylate (or acrylic acid or methacrylic acid) is added to 9-Fluorenbisphenol and 2-iodo-9,9-dimethylfluorene. It may include a derivative polymerized by esterification.

The naphthalene monomer may include a derivative obtained by specifically esterifying a monofunctional acrylate or methacrylate (or acrylic acid or methacrylic acid) to naphthalene substituted with a hydroxy group.

Specifically, the urethane-based monomer may refer to a derivative in which a urethane oligomer is prepared using bisphenol A or bisphenol F-type diisooctanate using glycols or polyester polyols, which are dihydric alcohols, and the terminal is substituted with an acryl group.

The sulfur-based monomer may specifically include a derivative polymerized by esterifying a monofunctional acrylate or methacrylate (or acrylic acid or methacrylic acid) to naphthalene thiol.

The monomer having two or more aromatic groups may be included in at least 20% by weight of the monomer mixture or the (meth) acrylic copolymer. Within this range, the refractive index is increased, the pattern visibility at the time of reliability is improved, and the effect of lowering the dielectric constant can be obtained. Preferably it may be included in 20 to 50% by weight, more preferably 20 to 35% by weight.

The monomer containing a carboxylic acid group may be (meth) acrylic acid, itaconic acid, maleic acid, or fumaric acid. These may be included alone or in combination of two or more.

The carboxylic acid group-containing monomer may be included in more than 0 wt% of the monomer mixture or (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 from 0.1 to 10% by weight, more preferably from 0.1 to 5% by weight, most preferably from 0.1 to 3% 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, unsaturated morpholine including vinyl morpholine, acryloyl morpholine, metaacroyl morpholine, etc., (meth) acrylate having a pyrrolidoneyl group, (meth) acrylate having a phosphate group, and the like. Can be.

The (meth) acrylic copolymer may be prepared by partial polymerization after adding an initiator to each monomer component. The polymerization is carried out until the 25 ° C viscosity of the (meth) acrylic copolymer becomes a viscous liquid of about 1,000 to 50,000 cPs. The coating is easy in the viscosity range, there is an excellent workability. The polymerization can be carried out by polymerization by UV irradiation.

Preferably it may be carried out in bulk photopolymerization conditions. Under bulk photopolymerization conditions, it is easy to polymerize monomers having two or more aromatic groups, such as phenoxy benzyl groups, and because the aromatic groups absorb ultraviolet rays to increase reactivity, a uniform and stable adhesive film can be prepared than conventional copolymers by solution polymerization. Can be. In addition, a copolymer having a weight average molecular weight of more than 2 million g / mol that can not be realized in the conventional solution polymerization can be prepared.

The initiator may preferably be a photopolymerization initiator. The photopolymerization initiator is activated by ultraviolet rays or electron beams to activate a carbon-carbon double bond in the adhesive film to generate a radical reaction.

Specific examples may include, but are not limited to, alpha-hydroxy ketone type compounds, benzyl ketal type compounds, or mixtures thereof. Hydroxy-2-methyl-1-phenyl-1-propanone, 2-hydroxy-1- [4- (2-hydroxyethoxy) phenyl] -2-methyl-1-propanone, and the like. The initiators may be used alone or in combination of two or more.

The initiator may be applied in an amount of 0.001 to 3 parts by weight, preferably 0.003 to 1 part by weight, based on 100 parts by weight of the monomer mixture for preparing a (meth) acrylic copolymer. Low light leakage and excellent durability can be obtained in the above range.

The (meth) acrylic copolymer may have a glass transition temperature (Tg) of -50 ° C to -5 ° C, preferably -31 ° C to -10 ° C. In the above range, the workability is excellent, and durability and adhesive strength are excellent.

The (meth) acrylic copolymer may have a viscosity of 25 ° C of 1,000 to 50,000 cPs, preferably 1,000 to 15,000 cPs.

The (meth) acrylic copolymer may have a weight average molecular weight of more than 2 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. Preferably, it may be 2.1 million to 5 million g / mol, more preferably 2.1 million to 3 million g / mol.

The (meth) acrylic copolymer does not need to be dissolved in a separate solvent during the coating process. That is, since it is applied as a solvent-free process, not only is the process easy and the coating process is easy, it is also possible to manufacture a pressure-sensitive adhesive film of a thick thickness of 10㎛ to 2mm.

The pressure-sensitive adhesive composition may further include an initiator.

Initiator

Details of the initiator are as described above.

The initiator may be applied in an amount of 0.001 to 3 parts by weight, preferably 0.003 to 1 part by weight, based on 100 parts by weight of the monomer mixture for preparing a (meth) acrylic copolymer. Low light leakage and excellent durability can be obtained in the above range.

The pressure-sensitive adhesive composition may further include a crosslinking agent.

Cross-linking agent

As a crosslinking agent, the polyfunctional (meth) acrylate which can be hardened by an active energy ray can be used preferably.

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; 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 Hexafunctional acrylates such as acrylonitrile-butadiene-acrylonitrile-butadiene-acrylonitrile, and the like, but are not limited thereto. They may be used alone or in combination of two or more.

Preferably, the polyfunctional (meth) acrylate of a polyhydric alcohol having 2 to 20 hydroxyl groups can be used.

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.

The crosslinking agent is 0 to 5 parts by weight, preferably 0.01 to 5 parts by weight, more preferably 0.03 to 3 parts by weight, based on 100 parts by weight of the (meth) acrylic copolymer or 100 parts by weight of the monomer mixture for preparing the (meth) acrylic copolymer, Most preferably, it may be included in 0.05 to 2 parts by weight.

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 silane coupling agent, but is not limited thereto.

The additive (e.g., silane coupling agent) is 0 to 5 parts by weight, preferably 0.01 to 5 parts by weight, more preferably 0.03 to 3 parts by weight, most preferably 0.05 to 100 parts by weight of the (meth) acrylic copolymer. To 2 parts by weight.

The pressure-sensitive adhesive composition may have a viscosity at 25 ° C of 1,000 to 50,000 cPs.

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

The adhesive composition which is another aspect of this invention may contain the (meth) acrylic-type copolymer of the monomer mixture containing 20 weight% or more of monomers which have two or more aromatic groups.

Details of the pressure-sensitive adhesive composition are as described above.

Another aspect of the present invention provides a method for producing a pressure-sensitive adhesive film comprising an alkyl (meth) acrylate having an alkyl group of C1-C20, an alicyclic containing (meth) acrylate, a monomer containing a hydroxyl group and a monomer having two or more aromatic groups. Polymerizing the monomer mixture to prepare a (meth) acrylic oligomer; Preparing an adhesive composition by mixing an initiator with the (meth) acrylic oligomer; And UV-curing the pressure-sensitive adhesive composition.

The pressure-sensitive adhesive composition may further include a crosslinking agent.

The (meth) acrylic oligomer does not include a solvent and may have a viscosity of 25 to 1,000 to 50,000 cPs.

Another aspect of the present invention relates to a display member.

Wherein the display member comprises: an optical film; And the adhesive film attached to one side or both sides of the optical film.

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 reflection film, an antireflection film, a compensation film, a brightness enhancement film, an orientation film, , A plastic LCD substrate, a transparent electrode film such as indium tin oxide (ITO), fluorinated tin oxide (FTO), aluminum doped zinc oxide (AZO), carbon nanotube (CNT), Ag nanowire, and graphene And the like. The manufacturing method of the optical film can be easily manufactured by those skilled in the art to which the present invention pertains.

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 can also be applied as a pressure-sensitive adhesive film to a conventional polarizing film as in the prior art.

1 is a sectional view of a display member according to one embodiment of the present invention.

Referring to FIG. 1, the display member 100 may include an optical film 110; It may include a pressure-sensitive adhesive film 120 formed on the optical film 110.

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.

Example  One

50 parts by weight of ethylhexyl acrylate (EHA), 5 parts by weight of isobornyl acrylate (IBOA), 19 parts by weight of 2-hydroxyethyl acrylate (HEA), 1 part by weight of acrylic acid (AA), phenoxybenzyl acrylate A mixture was prepared by mixing 25 parts by weight and 0.04 parts by weight of Irgacure ^TM 651 (2,2-dimethoxy-2-phenylacetophenone) (manufactured by Ciba Japan K.K.) as a photopolymerization initiator in a glass vessel. . The dissolved oxygen was replaced with nitrogen gas and then irradiated with ultraviolet light using a low pressure lamp (Sylvania BL Lamp) for a few minutes to partially polymerize the mixture to give a viscous liquid having a viscosity of about 15000 cPs.

In the resulting composition, 0.1 parts by weight of epoxy silane (KBM-403: manufactured by Shin-Etsu) as a silane compound and 0.3 parts by weight of additional polymerization initiator Irgacure ^TM 651, and HDDA (1,6-hexanediol diacrylate as a crosslinking agent) 0.3 parts by weight of the adhesive composition was prepared.

The resulting pressure-sensitive adhesive composition was coated on a 50 μm thick polyester film (release film) to perform a release treatment to a thickness of 175 μm. After the release film was covered in order to remove oxygen that adversely affects the medium pressure, ultraviolet rays were irradiated with a low pressure lamp (Sylvania BL Lamp) on both sides of the release film for about 6 minutes to obtain a transparent adhesive film.

Example  2

The same procedure as in Example 1 was applied except that 25 parts by weight of 2-phenylphenoxyethyl acrylate was used instead of 25 parts by weight of phenoxybenzyl acrylate.

Example 3

45 parts by weight of ethylhexyl acrylate (EHA), 10 parts by weight of isobornyl acrylate (IBOA), 20 parts by weight of 2-hydroxyethyl acrylate (HEA), 25 parts by weight of phenoxybenzyl acrylate and a photopolymerization initiator A mixture was prepared by mixing 0.04 parts by weight of Mercure ^™ 651 (2,2-dimethoxy-2-phenylacetophenone) (manufactured by Ciba Japan K.K.) in a glass vessel. The prepared mixture was obtained in the same manner as in Example 1 to give a viscous liquid.

The pressure-sensitive adhesive composition was prepared by adding 0.3 parts by weight of additional polymerization initiator Irgacure 651 ^™ to the resulting composition.

The resulting pressure-sensitive adhesive composition was obtained in the same manner as in Example 1.

Example  4

The same procedure as in Example 3 was applied except that 25 parts by weight of 2-phenylphenoxyethyl acrylate was used instead of 25 parts by weight of phenoxybenzyl acrylate.

Comparative Example  One

Except for applying 25 parts by weight of benzyl acrylate instead of 25 parts by weight of phenoxybenzyl acrylate was carried out in the same manner.

Comparative Example  2

The same procedure as in Example 1 was applied except that 25 parts by weight of phenoxyethyl acrylate was used instead of 25 parts by weight of phenoxybenzyl acrylate.

Comparative Example  3

In Example 3, 68 parts by weight of ethylhexyl acrylate (EHA), 7 parts by weight of isobornyl acrylate (IBOA), 25 parts by weight of 2-hydroxyethyl acrylate (HEA), 0 weight of phenoxybenzyl acrylate The same procedure was followed except that parts were used.

Comparative Example  4

67 parts by weight of ethylhexyl acrylate (EHA), 7 parts by weight of isobornyl acrylate (IBOA), 25 parts by weight of 2-hydroxyethyl acrylate (HEA), and 1 part by weight of acrylic acid (AA) in a glass container It is preferable to thermally polymerize using AIBN (Azobisisobutyronitrile) as a thermal polymerization initiator in a mixed state, and it is prepared by bulk polymerization. The dissolved oxygen was replaced with nitrogen gas and then bulk polymerized at 70 ° C. for several minutes to partially polymerize the mixture to obtain a viscous liquid having a viscosity of about 25000 cP.

Comparative Example  5

In Example 1, 56 parts by weight of ethylhexyl acrylate (EHA), 6 parts by weight of isobornyl acrylate (IBOA), 20 parts by weight of 2-hydroxyethyl acrylate (HEA), 1 part by weight of acrylic acid (AA) The same process was conducted except that 17 parts by weight of phenoxybenzyl acrylate was used.

The physical properties of the adhesive films prepared above were evaluated and shown in Table 1.

(1) Refractive index: Measured by ASTM D1218 method. It was coated on a release PET film to have a thickness of 200 μm, the total light amount was cured at 3000 mJ / cm ² , and the refractive index was measured by an ABBE5 (Bellingham / stanley Ltd) instrument.

(2) Durability: After bonding PC film / ITO film / Glass and PET film, it is allowed to stand at 60 ℃ / 90% relative humidity for 500 hours. Was observed, and evaluated according to the following criteria.

○: Good (no bubbles or peeling phenomenon)

△: good (some bubbles or peeling phenomenon)

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

(3) Average dielectric constant: Using agilent E5515E 8960 for adhesive film (width x length x thickness = 4cm x 6cm x 1mm) while increasing the frequency in the range from frequency 1.0 x 10 ³ Hz to 1.0 x 10 ⁶ Hz Measure the dielectric constant. The dielectric constant average value is measured according to the following Equation 1.

)Equation 1) average dielectric constant (

)

(X ₁ : dielectric constant measured value at first frequency

X ₂ : permittivity measurement at second frequency

X _{n -1} : dielectric constant measurement at frequency n-1

X _n : Dielectric constant measurement at nth frequency

n is an integer from 2-100,

Provided that the n-1th frequency <nth frequency)

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Acrylic
Copolymer EHA 50 50 45 45 50 50 68 67 56 IBOA 5 5 10 10 5 5 7 7 6 HEA 19 19 20 20 19 19 25 25 20 AA One One - - One One - One One Phenoxybenzyl acrylate 25 - 25 - - - - - 17 2-phenylphenoxyethyl acrylate - 25 - 25 - - - - - Benzyl acrylate - - - - 25 - - - - Phenoxy ethyl acrylate - - - - - 25 - - - Initiator 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Cross-linking agent 0.3 0.3 - - 0.3 0.3 0.3 0.3 0.3 Epoxy silane 0.1 0.1 - - 0.1 0.1 - - 0.1 Manufacturing method UV curing UV curing UV Curing UV curing UV curing UV curing UV curing Heat curing UV curing Copolymer weight average molecular weight (g / mol) 3 million 2.6 million 3 million 2.5 million 2.5 million 2 million 4 million 50 million 3 million  Copolymer glass transition temperature (℃) -31 -22 -28 -18 -28 -30 -41 -38 -34 Copolymer viscosity
(25 ° C, cPs) 15,000 2,500 13,000 2,300 14,000 15,000 3,000 25,000 13,000 Refractive index 1.51 1.53 1.51 1.53 1.49 1.48 1.47 1.47 1.48 durability ○ ○ ○ ○ × ○ × × ○ Permittivity average 2.9 2.9 2.8 2.9 3.0 3.0 4.1 4.3 3.4

As shown in Table 1, the adhesive film of the present invention has a high refractive index, high pattern hiding power, excellent durability and low dielectric constant.

On the other hand, the pressure-sensitive adhesive film of Comparative Example 1-2 containing a (meth) acrylic copolymer made of a monomer mixture containing a monomer having one aromatic group instead of a monomer having two or more aromatic groups has a refractive index compared to the present invention. Low pattern hiding power and high dielectric constant.

In addition, the pressure-sensitive adhesive film of Comparative Example 3-4 including a (meth) acrylic copolymer made of a monomer mixture containing no monomer having an aromatic group at all has a low refractive index and a low pattern hiding power, regardless of the curing method. It was poor in durability, and had a high dielectric constant.

In addition, the pressure-sensitive adhesive film of Comparative Example 5 including a (meth) acrylic copolymer made of a monomer mixture containing less than 20% by weight of a monomer having two or more aromatic groups has a low refractive index, and thus has a low pattern hiding power. The dielectric constant was high.

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 (23)

It contains the hardened | cured material of a (meth) acrylic-type copolymer containing composition,
Adhesive film with a refractive index of 1.5-1.6.
The adhesive film according to claim 1, wherein the (meth) acrylic copolymer comprises a (meth) acrylic copolymer of a monomer mixture containing a monomer having two or more aromatic groups.
The pressure-sensitive adhesive film of claim 1, wherein the (meth) acrylic copolymer comprises a (meth) acrylic copolymer of a monomer mixture containing 20% by weight or more of a monomer having two or more aromatic groups.
The monomer of claim 2, wherein the monomer having two or more aromatic groups is one of a monomer of Formula 2, a fluorene monomer, a naphthalene monomer, a urethane monomer having two or more aromatic groups, and a sulfur monomer having two or more aromatic groups. Adhesive film containing the above:
(2)

(In the above, Y ₁ is one or more substituents selected from the group consisting of a substituted or unsubstituted phenoxy group, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and a substituted or unsubstituted arylalkyl group having 7 to 21 carbon atoms. An aryl group having 6 to 20 carbon atoms,
X ₁ is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted -R- (CH ₂ ) n-(wherein R is O, S, NH or NR '(R' is Hydrogen or an alkyl group having 1-5 carbon atoms, n is an integer of 1-10),
R ₁ is hydrogen or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms).
The pressure-sensitive adhesive film of claim 1, wherein the (meth) acrylic copolymer comprises 10 wt% or more of the functional group represented by Formula 1 below:
&Lt; Formula 1 >

(In the above, Y ₁ is one or more substituents selected from the group consisting of a substituted or unsubstituted phenoxy group, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and a substituted or unsubstituted arylalkyl group having 7 to 21 carbon atoms. An aryl group having 6 to 20 carbon atoms,
X ₁ is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted -R- (CH ₂ ) n-(wherein R is O, S, NH or NR '(R' is Hydrogen or an alkyl group having 1-5 carbon atoms, n is an integer of 1-10).
The pressure-sensitive adhesive film of claim 2, wherein the monomer having two or more aromatic groups comprises at least one of phenoxybenzyl (meth) acrylate and phenylphenoxyethyl (meth) acrylate.
According to claim 1, wherein the (meth) acrylic copolymer is 10-50% by weight of alkyl (meth) acrylate having an alkyl group of C1-C20, 1-30% by weight of alicyclic containing (meth) acrylate, monomer containing hydroxyl group An adhesive film comprising a copolymer of a monomer mixture comprising 10-30% by weight and 20-50% by weight of monomers having two or more aromatic groups.
The pressure-sensitive adhesive film of claim 7, wherein the monomer mixture further comprises 0.1-10% by weight of a monomer having a carboxylic acid group.
The pressure-sensitive adhesive film of claim 1, wherein the (meth) acrylic copolymer has a viscosity of 1,000-50,000 cPs at 25 ° C.
The pressure-sensitive adhesive film of claim 1, wherein the (meth) acrylic copolymer has a weight average molecular weight of more than 2 million g / mol.
The pressure-sensitive adhesive film of claim 1, wherein the pressure-sensitive adhesive film comprises a cured product of the composition including the (meth) acrylic copolymer, an initiator, and a crosslinking agent.
The pressure-sensitive adhesive film of claim 11, wherein the composition further comprises an epoxy silane coupling agent.
The adhesive film of claim 1, wherein the adhesive film has a dielectric constant average value of less than three.
The pressure-sensitive adhesive film of claim 1, wherein the pressure-sensitive adhesive film has a thickness of 10 μm to 2 mm.
Adhesive composition containing the (meth) acrylic-type copolymer of the monomer mixture containing 20 weight% or more of monomer which has two or more aromatic groups.
The monomer of claim 15, wherein the monomer having two or more aromatic groups is one of a monomer of Formula 2, a fluorene monomer, a naphthalene monomer, a urethane monomer having two or more aromatic groups, and a sulfur monomer having two or more aromatic groups. Adhesive composition containing the above:
(2)

(In the above, Y ₁ is one or more substituents selected from the group consisting of a substituted or unsubstituted phenoxy group, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and a substituted or unsubstituted arylalkyl group having 7 to 21 carbon atoms. An aryl group having 6 to 20 carbon atoms,
X ₁ is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted -R- (CH ₂ ) n-(wherein R is O, S, NH or NR '(R' is Hydrogen or an alkyl group having 1-5 carbon atoms, n is an integer of 1-10),
R ₁ is hydrogen or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms).
The pressure-sensitive adhesive composition of claim 15, wherein the monomer having two or more aromatic groups comprises at least one of phenoxybenzyl (meth) acrylate and phenylphenoxyethyl (meth) acrylate.
The copolymer according to claim 15, wherein the copolymer is 10-50% by weight of an alkyl (meth) acrylate having an alkyl group of C1-C20, 1-30% by weight of an alicyclic containing (meth) acrylate, and 10-30% by weight of a hydroxyl group-containing monomer. A pressure-sensitive adhesive composition comprising a copolymer of a monomer mixture comprising% and 20-50% by weight of monomers having two or more aromatic groups.
The pressure-sensitive adhesive composition of claim 18, wherein the monomer mixture further comprises 0.1-10% by weight of a monomer having a carboxylic acid group.
The pressure-sensitive adhesive composition of claim 15, wherein the composition further comprises a crosslinking agent and an epoxy-based silane coupling agent.
Optical film; And
A display member attached to one or both sides of the optical film and comprising the adhesive film of any one of claims 1 to 14.
The display member of claim 21, wherein the optical film is a polarizing film.
The method of claim 21, wherein the optical film is indium tin oxide (ITO), fluorinated tin oxide (FTO), aluminum dopped zinc oxide (AZO), carbon nanotube (CNT), Ag nanowire (nanowire), graphene (graphene) Display member containing the film in which 1 or more types are laminated | stacked.

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