KR102309379B1 - Adhesive sheet, optical member and display device using the same - Google Patents

Abstract

The pressure-sensitive adhesive sheet according to the present invention has a storage modulus of 5.0×10 ⁴ to 2.0×10 ⁶ Pa at 25° C. and 1 Hz, and a storage modulus increase rate of 20% or more after additional UV curing.
The pressure-sensitive adhesive sheet according to the present invention has an advantage in that it has excellent step absorbency and excellent storage modulus.

Description

Adhesive sheet, optical member and display including same {ADHESIVE SHEET, OPTICAL MEMBER AND DISPLAY DEVICE USING THE SAME}

The present invention relates to an adhesive sheet, an optical member including the same, and a display device.

In recent years, an input device used in combination with a touch panel or the like in various display devices such as a liquid crystal display (LCD) has been widely used. For example, a touch panel is installed in a mobile terminal such as a smart phone or a tablet.

In the manufacture of such a display device or an input device, an optically clear adhesive (OCA) is used for bonding various optical members. Specifically, the optical adhesive sheet is used as an adhesive film for interlayer adhesion for laminating components in an optical display device or for attaching a touch screen of a mobile phone.

However, since optical members such as polarizing plates and retardation plates included in display devices are easily contracted by heat, shrinkage occurs due to thermal history, and as a result, the pressure-sensitive adhesive sheet laminated on the optical member cannot follow the shrinkage, There are some problems in that peeling occurs at the interface, such as lifting and peeling, or light leakage due to misalignment of the optical axis of the optical member due to the stress at the time of contraction of the optical member.

Korean Patent Application Laid-Open No. 2013-0051921 relates to an optical pressure-sensitive adhesive sheet, comprising a (meth)acrylic copolymer of a monomer containing (meth)acrylic acid ester having a UV cross-linkable site, and before UV cross-linking The storage modulus is 5.0 × 10 ⁴ to 1.0 × 10 ^{6 Pa at 30°C and 1 Hz, 5.0 × 10 4} Pa or less at 80°C and 1 Hz, and the storage modulus after UV crosslinking is 1.0 × at 130°C and 1 Hz Disclosed is a content relating to an ultraviolet cross-linkable pressure-sensitive adhesive sheet of 10 ^{3 Pa or more.}

In addition, Korean Patent Laid-Open No. 2010-0138979 discloses an energy ray-curable polymer in which a radical generator that initiates a polymerization reaction under excitation by an energy ray, and an energy ray polymerizable group are bonded to a main chain or a side chain.

However, in the case of the conventional adhesive sheet, it may be difficult to apply it to an additional UV curing system, and it is a situation that does not satisfy the step absorbency applicable to a flat panel display as well as a flexible display.

Therefore, there is a demand for the development of a pressure-sensitive adhesive sheet having excellent step absorbency and excellent storage modulus and thus excellent stress relaxation characteristics.

Republic of Korea Patent Publication No. 2013-0051921 (2013.05.21.) Republic of Korea Patent Publication No. 2010-0138979 (2010.12.31.)

An object of the present invention is to solve the above problems, and an object of the present invention is to provide an adhesive sheet having excellent step absorbency and excellent storage modulus.

Another object of the present invention is to provide an optical member and a display device having excellent durability.

^{The present invention for achieving the above object provides a pressure-sensitive adhesive sheet having a storage modulus of 5.0×10 4} to 2.0×10 ⁶ Pa at 25° C. and 1 Hz, and a storage elastic modulus increase rate of 20% or more after additional UV curing.

In addition, the present invention provides an optical member comprising the above-described pressure-sensitive adhesive sheet.

In addition, the present invention provides a display device including the above-described optical member.

The pressure-sensitive adhesive sheet according to the present invention has an excellent step absorption property and an excellent increase rate of the storage elastic modulus after additional UV curing.

In addition, the optical member and the display device including the above-described pressure-sensitive adhesive sheet has an advantage of excellent durability.

1 to 4 are diagrams showing ¹ H NMR according to the synthesis example.

Hereinafter, the present invention will be described in more detail.

In the present invention, when a member is said to be located "on" another member, this includes not only a case in which a member is in contact with another member but also a case in which another member exists between the two members.

In the present invention, when a part "includes" a certain component, this means that other components may be further included rather than excluding other components unless otherwise stated.

<Adhesive sheet>

One aspect of the present invention relates to an adhesive sheet having a storage elastic modulus at 25°C and 1 Hz of 5.0×10 ⁴ to 2.0×10 ⁶ Pa, and having a storage elastic modulus increase rate of 20% or more after further UV curing.

In the present invention, the "storage modulus" may be measured using a viscoelasticity measuring device (MCR-301, 　 Anton Paar). More specifically, set the size of the adhesive sheet sample to 30mm in length × 30mm in width, and attach the measurement sample to the glass plate and attach it to the measuring tip. It can calculate|require by measuring under the conditions of temperature increase rate 　 5 degreeC/min, and reading the measured value at 25 degreeC.

After the additional UV curing, the adhesive sheet may have a storage elastic modulus increase rate of 20% or more, preferably 20 to 200%, and more preferably 40 to 200%.

Specifically, in the pressure-sensitive adhesive sheet according to the present invention, the storage elastic modulus before additional UV curing satisfies the above range, and the storage elastic modulus increase rate after additional UV curing satisfies the above range.

In short, the pressure-sensitive adhesive sheet according to the present invention has excellent step filling or gap-filling properties of the pressure-sensitive adhesive sheet in the step or protrusion of the object as the storage elastic modulus before further UV curing satisfies the above range. Thereafter, as secondary curing can be performed by the polyfunctional ketoprofen-based compound, which will be described later, there is an advantage in that the storage elastic modulus is improved while the step absorption is excellent, and thus the durability is excellent.

The adhesive sheet may have a storage modulus after additional UV curing of 20% or more of the storage modulus before additional UV curing, such as 6.0×10 ⁴ to 2.4×10 ⁶ Pa or more.

When the storage modulus of the pressure-sensitive adhesive sheet after additional UV curing satisfies the above range, it is preferable because it has the advantage of excellent durability in heat resistance conditions such as 60°C and 93%RH and heat-resistant conditions such as 90°C.

In another embodiment of the present invention, the pressure-sensitive adhesive sheet, a repeating unit derived from an acrylic monomer containing a C1-C20 straight-chain, branched-chain or alicyclic alkyl group and a repeating unit derived from an acrylamide monomer; an acrylic polymer comprising ; and a polyfunctional ketoprofen-based compound containing two or more ketopropenyl groups represented by the following formula (1). and the repeating unit derived from the acrylamide monomer may include a cured product of the pressure-sensitive adhesive composition in an amount of 5 to 40 wt%.

[Formula 1]

Specifically, the acrylic monomer may be an alkyl (meth)acrylate containing a straight-chain, branched-chain or alicyclic alkyl group satisfying the carbon number.

The alkyl (meth) acrylate having the straight-chain or branched alkyl group is not particularly limited, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate , butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate and eicosyl (meth) acrylate. can

The alkyl (meth) acrylate containing the alicyclic alkyl group is trimethylcyclohexyl acrylate, t-butyl cyclohexyl acrylate, dicyclopentadiene (meth) acrylate, trimethylcyclohexyl methacrylate, cyclohexyl Methacrylate, isobornyl methacrylate, 2-ethylhexyl methacrylate, tetrahydrofurfuryl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, 4-t-butyl cyclohexyl methacrylate and the like, but is not limited thereto.

The acrylic monomer is present in the acrylic polymer and can serve to express adhesion by increasing wettability when bonding with an adherend, thereby providing an advantage in that a pressure-sensitive adhesive sheet having a high step absorption rate can be obtained.

The repeating unit derived from the acrylic monomer may be included in an amount of 60 to 95 wt%, preferably 70 to 95 wt%, more preferably 80 to 95 wt%, based on 100 wt% of the total acrylic polymer.

Specifically, the acrylic polymer may be polymerized using an acrylic monomer in the above range and an acrylamide-based monomer to be described later, and when the repeating unit derived from the acrylic monomer is included within the above range, the step absorbency is excellent, and appropriate adhesive strength and reliability It is possible to manufacture an adhesive sheet having

The acrylamide monomer is a monomer having at least one (meth)acryloyl group and an amide bond in the molecule, and N-hydroxyl such as N-hydroxyethyl (meth)acrylamide and N-methylol (meth)acrylamide. alkyl (meth) acrylamide monomer;

N,N-dihydroxyalkyl (meth)acrylamide monomers such as N,N-dihydroxyethyl (meth)acrylamide and N,N-dimethylol (meth)acrylamide;

N-alkyloxyalkyl such as N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, N-methoxyethyl (meth) acrylamide, and N-ethoxyethyl (meth) acrylamide. (meth)acrylamide 　 monomer;

N,N-dimethoxymethyl (meth)acrylamide, N,N-diethoxymethyl (meth)acrylamide, N,N-dimethoxyethyl (meth)acrylamide and N,N-diethoxyethyl (meth)acrylamide N,N-dialkyloxyalkyl (meth)acrylamide ? monomers such as amide?;

N-monoalkyl (meth)acrylamide monomers such as N-methyl (meth) acrylamide, N-isopropyl acrylamide, N-butyl (meth) acrylamide and N-hexyl (meth) acrylamide;

N,N-dialkyl (meth)acrylamide monomers such as N,N-dimethyl (meth)acrylamide and N,N-diethyl (meth)acrylamide;

N-aminoalkyl (meth)acrylamide monomers such as aminomethyl (meth)acrylamide and aminoethyl (meth)acrylamide;

N-mercaptoalkyl (meth)acrylamide monomers such as mercaptomethyl (meth)acrylamide and mercaptoethyl (meth)acrylamide; and

(meth)acrylamide monomers having an aliphatic heterocyclic structure such as N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine and N-acryloylpyrrolidine; and the like. have.

A commercially available product can be used for the (meth)acrylamide 　 monomer. Specifically, N-hydroxyethyl acrylamide (trade name "HEAA", manufactured by Kojin Corporation), N-methoxymethyl acrylamide (trade name "NMMA", manufactured by MRC Unitech), N-butoxymethyl acrylamide ( A brand name "NBMA", the MRC Unitech company make), N-methoxymethylmethacrylamide (a brand name "Wasma 2MA", the Kasano Kosan company make), etc. are mentioned.

In one embodiment of the present invention, the acrylamide monomer may include at least one selected from the group consisting of compounds represented by the following Chemical Formulas 2 and 3.

[Formula 2]

[Formula 3]

In Formulas 2 and 3,

R1 is each independently hydrogen or a methyl group,

R2 is each independently a C1 to C10 straight-chain or branched hydrocarbon group.

The C1 to C10 linear hydrocarbon group may include, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, and octyl, but is not limited thereto.

The C1 to C10 branched chain hydrocarbon group is, for example, methylethyl, dimethylmethyl, 2-methylpropyl, 2,2-dimethylpropyl, 2-methylbutyl, 2,3-dimethylbutyl, 2,2-dimethylbutyl, 2- Ethyl-2-methylpropyl, 2-methylpentyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl, 2,4-dimethylpentyl, 2,3,4-trimethylpentyl, 2-ethyl-2-methylpen A tyl group, 2-ethylhexyl group, etc. are mentioned. The number of carbon atoms of the branched chain hydrocarbon group may be specifically C2 to C10.

When the acrylamide monomer includes at least one selected from the group consisting of compounds represented by Chemical Formulas 2 and 3, since the acrylic polymer contains an amide group instead of an acid group (-COOH) included in the conventional pressure-sensitive adhesive composition, metal wiring , it is possible to impart excellent cohesive strength through intramolecular hydrogen bonding and chelating bonding with ions remaining in the adherend such as metal ions or glass remaining in the sheet, without causing corrosion to the metal electrode layer, etc.

In addition, there is an advantage in that the wettability is improved to obtain a pressure-sensitive adhesive composition excellent in step absorbency.

The repeating unit derived from the acrylamide monomer is included in an amount of 5 to 40% by weight, preferably 5 to 20% by weight, based on 100% by weight of the total acrylic polymer. When the repeating unit derived from the acrylamide monomer is included within the above range, there is an advantage in that it is possible to obtain a pressure-sensitive adhesive composition having excellent wettability and improved double curvature and step absorption.

The pressure-sensitive adhesive composition according to the present invention includes a polyfunctional ketoprofen-based compound containing two or more ketopropenyl groups represented by the following formula (1).

[Formula 1]

That is, in the present specification, the ketoprofen-based compound may refer to a compound containing a ketopropenyl group represented by Formula 1 above, and the polyfunctional ketoprofen-based compound according to the present invention is a ketoprofen-based compound represented by Formula 1 above. A compound containing two or more phenyl groups may be referred to.

Although not limited by theory, the ketoprofen-based compound according to the present invention has a linking site at the meta position of benzophenone, preventing the absorption wavelength shift, and maintaining the unique wavelength of benzophenone. guessed

The polyfunctional ketoprofen-based compound can be synthesized using available raw materials and combining conventional reactions. For example, the ketoprofen-based compound represented by Formula 1 may be synthesized through the following method, but is not limited thereto.

As a starting material, ketoprofen, trimethylol propane, and para-toluenesulfonic acid are added to a solvent and refluxed at 110 to 130° C. for 2 to 5 hours. When the reaction is completed, water is added to the resulting mixture, cooled and stirred. Thereafter, water and the solvent may be removed to produce a polyfunctional ketoprofen-based compound.

In this case, the solvent may be a non-polar solvent, specifically, toluene, diethyl ether, cyclohexane, chloroform or carbon tetrachloride may be used, but is not limited thereto.

When the ketoprofen and trimethylol propane are added to a solvent and reacted, a catalyst such as para-toluenesulfonic acid may be added to the reaction, and the catalyst is not limited thereto, but for example, para-toluenesulfonic acid, sulfuric acid, methane Sulfonic acid or acetic acid may be used.

The reaction time may be 2 to 5 hours, preferably 3 to 4 hours, and the reaction temperature may be 110 to 140°C, preferably 120 to 130°C.

After the reaction is completed, water is added to the resulting mixture, cooled to room temperature, and stirred.

Thereafter, the polyfunctional ketoprofen-based compound can be obtained by removing water and solvent through filtration and drying.

Specifically, the polyfunctional ketoprofen-based compound may be represented by the following formula (4).

[Formula 4]

In Formula 4,

X is O, NH, or S;

Z is selected from the group consisting of aliphatic, aromatic, aralkyl, heteroaromatic and cycloaliphatic groups, and represents an organic spacer that may be interrupted by a group selected from the group consisting of an ester group, an ether group, an amine group, an amide group and a urethane group,

n is an integer greater than or equal to 3;

In Formula 4, n is preferably an integer of 5 to 6.

More specifically, the polyfunctional ketoprofen-based compound may be represented by any one of Formulas 5 to 8 below.

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

When the polyfunctional ketoprofen-based compound contains two or more ketopropenyl groups represented by Formula 1, the generation of outgas is suppressed, so that an adhesive sheet prepared using the polyfunctional ketoprofen-based compound and the same There is an advantage in that the reliability of the optical member and the display device is prevented from being deteriorated, and the storage elastic modulus is improved after additional UV curing, so that the durability is excellent.

In another embodiment of the present invention, the pressure-sensitive adhesive sheet further comprises an acrylic monomer and an acrylamide monomer containing a C1 to C20 straight chain, branched chain or alicyclic alkyl group, the acrylic polymer, the C1 to C20 straight chain, The acrylic monomer containing a branched or alicyclic alkyl group and the acrylamide monomer constitute the acrylic syrup, and the polyfunctional ketoprofen-based compound is contained in an amount of 0.1 to 10 parts by weight, preferably 0.5 parts by weight, based on 100 parts by weight of the total acrylic syrup. to 5 parts by weight, more preferably 1 to 3 parts by weight.

When the polyfunctional ketoprofen-based compound is included within the above range, additional photocuring may occur efficiently. Specifically, since the pressure-sensitive adhesive composition according to the present invention includes the polyfunctional ketoprofen-based compound, a thick film process is possible. More specifically, the polyfunctional ketoprofen-based compound may serve as a plasticizer and a crosslinking agent at the same time. For this reason, there is an advantage in that it is possible to obtain a pressure-sensitive adhesive sheet having excellent wettability and step absorption properties by first curing the pressure-sensitive adhesive composition to obtain an adhesive sheet having excellent wettability and step absorbency and then secondary curing to obtain an adhesive sheet having excellent elasticity modulus as well as wettability and step absorption properties.

In another embodiment of the present invention, based on 100% by weight of the total acrylic polymer, a hydroxyl group-containing monomer may be further included in an amount of more than 0 and 20% by weight or less, preferably more than 0 and 10% by weight or less.

When the hydroxyl group-containing monomer is further included, cohesive force may be improved, durability may be improved, adhesive force may also be improved, and wettability may be improved.

In another embodiment of the present invention, the acrylic polymer may be included in an amount of 10 to 60% by weight, preferably 15 to 50% by weight, based on 100% by weight of the total pressure-sensitive adhesive composition. When the acrylic polymer is included within the above range, the cohesive force of the pressure-sensitive adhesive composition is maximized, and there is an advantage in that the step filling property improvement effect is excellent.

In another embodiment of the present invention, the pressure-sensitive adhesive composition may further include a photoinitiator.

Specifically, the photoinitiator may be a photopolymerization initiator having a maximum absorption wavelength at a wavelength of 380 nm or more, and in this case, there is an advantage in that it is possible to manufacture an adhesive sheet having excellent wettability and step absorption as well as a double curvature through secondary curing.

The photopolymerization initiator is not limited as long as it has a maximum absorption wavelength at a wavelength of 380 nm or more.

For example, the photopolymerization initiator is 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), bis(2,6-dimethoxybenzoyl)-2 ,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, ethyl(2,4,6-trimethylbenzoyl)phenylphosphinate (TPO-L), etc. can

In addition, as a commercially available product of the photopolymerization initiator, Irgacure 819, 907 (Cibas), etc. can be applied.

When the photopolymerization initiator is further included, there is an advantage that double curing is possible. Since the photopolymerization initiator can serve as an initiator at a wavelength of 380 nm or more, which is a relatively long wavelength compared to the polyfunctional ketoprofen-based compound, the photopolymerization initiator is irradiated with light using a wavelength of 380 nm or more to prepare a pressure-sensitive adhesive sheet, and a wavelength of less than 380 nm It is possible to perform double curing due to the polyfunctional ketoprofen-based compound using In this case, the polyfunctional ketoprofen-based compound may initiate polymerization of some uncured monomers, and may serve as a crosslinking agent by extracting hydrogen from other compounds included in the pressure-sensitive adhesive composition.

When the pressure-sensitive adhesive sheet according to the present invention is manufactured by double curing as described above, it is further cross-linked with an acrylic resin to improve the mechanical properties of the pressure-sensitive adhesive sheet after attaching the object, and has the advantage of further excellent durability.

The photopolymerization initiator may be included in an amount of 0.1 to 5 parts by weight, preferably 0.5 to 5 parts by weight, more preferably 0.5 to 3 parts by weight based on 100 parts by weight of the total acrylic syrup.

When the photopolymerization initiator is included within the above range, the photocuring rate is slowed, and a phenomenon in which the initial durability of the pressure-sensitive adhesive sheet is lowered can be suppressed. In addition, there is an advantage in that it is possible to suppress the deterioration of the properties of the pressure-sensitive adhesive sheet due to the residual components after the primary photocuring and the reduction in transparency due to the yellowing phenomenon.

The pressure-sensitive adhesive composition according to the present invention may further include a (meth)acrylate-based monomer as a diluting monomer. The diluent monomer is a component that imparts durability to the pressure-sensitive adhesive composition and maintains the storage modulus, and can facilitate coating by diluting the solvent-free pressure-sensitive adhesive composition to adjust the viscosity.

Specifically, the (meth)acrylic monomer is n-butyl (meth) acrylate, 2-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylic rate, cyclohexyl (meth) acrylate), N-vinyl pyrrolidone, 2-ethylhexyl (meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate , isopropyl (meth) acrylate, pentyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-methylbutyl (meth) acrylate, n-nonyl (meth) acrylic Rate, isononyl (meth) acrylate, isoamyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, isobornyl (meth) acrylate, 4-methyl-2-pentyl (meth)acrylate, dodecyl (meth)acrylate, 2-dodecylthioethyl (meth)acrylate, lauryl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, allyl (meth)acrylate, stearyl (meth)acrylate, phenoxy monofunctional monomers such as ethyl (meth)acrylate, tetrafurfuryl (meth)acrylate, tetrahydrofuryl (meth)acrylate, and acryloylmorpholine; 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propane Diol diacrylate, 1,9-nonanediol diacrylate, ethylene glycol di(meth)acrylate, bisphenol A-ethylene glycol diacrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate Acrylate, tetraethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylic rate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified di(meth)acrylate, bis(2-hydroxyethyl)isocyanurate di( Meth)acrylate, di(acryloxyethyl)isocyanurate, allylated cyclohexyldi(meth)acrylate, dimethyloldicyclopentane diacrylate, ethylene oxide-modified hexahydrophthalic acid diacrylate, tricyclodecanedimethanol bifunctional monomers such as acrylate, neopentyl glycol-modified trimethylolpropane diacrylate, and adamantane diacrylate; Trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid modified trimethylolpropane tri(meth)acrylate, propylene oxide modified trimethylolpropane tri trifunctional monomers such as (meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, tris(acryloxyethyl)isocyanurate, and glycerol tri(meth)acrylate; tetrafunctional monomers such as diglycerin tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropanetetra(meth)acrylate, and tetramethylolpropanetetra(meth)acrylate; 5 functional monomers such as dipentaerythritol penta(meth)acrylate and propionic acid-modified dipentaerythritol penta(meth)acrylate; Hexafunctional monomers, such as dipentaerythritol hexa(meth)acrylate and caprolactone modified dipentaerythritol hexa(meth)acrylate, etc. are mentioned.

The diluent monomer may be included in 50 to 90 parts by weight, preferably 60 to 80 parts by weight, based on 100 parts by weight of the pressure-sensitive adhesive composition. .

The pressure-sensitive adhesive composition according to the present invention may further include a thiol-based molecular weight modifier. The thiol-based molecular weight modifier may promote termination and initiation of chain growth during radical polymerization of the acrylic polymer, thereby controlling the degree of radical polymerization of the acrylic polymer and the like and controlling the molecular weight of the acrylic polymer. Preferably, a bifunctional or more multifunctional thiol-based molecular weight regulator may be used.

For example, the thiol-based molecular weight modifier may be 2-ethylhexyl 3-mercaptopropionate, n-octyl 3-mercaptopropionate, methoxybutyl 3-mercaptopropionate, or tetraethylene glycol bis(3-mer). captopropionate), trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), tris[(3-mercaptopropionyloxy)-ethyl]- Isocyanurate and the like may be included, and these may be used alone or in combination of two or more.

In addition, the pressure-sensitive adhesive composition according to the present invention may further include additional additives within the range that does not impair the above-mentioned purpose. For example, solvents, silane coupling agents, light stabilizers, defoamers, fillers. Components such as lubricants, surfactants, and corrosion inhibitors may be appropriately included according to characteristics.

A photopolymerization initiator may be added to the acrylic syrup containing the acrylic polymer and the polyfunctional ketoprofen-based compound to form a pressure-sensitive adhesive composition. In this case, the acrylic syrup may further contain a diluting monomer. A pressure-sensitive adhesive sheet may be manufactured by applying the pressure-sensitive adhesive composition on a release film to form a preliminary coating film, and curing the preliminary coating film through primary photocuring.

Specifically, the pressure-sensitive adhesive composition may be applied on a release film to form a preliminary coating film, and the preliminary coating film may be cured through primary photocuring to prepare an adhesive sheet.

Preliminary ultraviolet irradiation may be further performed on the acrylic syrup before the first photocuring, but is not limited thereto. The viscosity of the acrylic syrup may be increased by the preliminary ultraviolet irradiation, thereby improving the easiness of the subsequent process.

After the release film is peeled off, the pressure-sensitive adhesive sheet may be attached to an object, and secondary photocuring may be performed.

The primary photocuring and the secondary photocuring may include UV irradiation of different wavelengths, respectively. In some embodiments, the UV irradiation wavelength of the secondary photocuring may be smaller than the UV irradiation wavelength of the primary photocuring.

In exemplary embodiments, the primary photocuring may be performed by irradiating ultraviolet rays having a wavelength of 380 nm or more, and the secondary photocuring may be irradiating ultraviolet rays having a wavelength of less than 380 nm. In some embodiments, in the first photocuring, light in the UVV band, for example, ultraviolet rays having a wavelength of 380 nm or more, is irradiated as described above, and in the secondary photocuring, ultraviolet rays having a wavelength less than about 380 nm are irradiated. can be investigated

The pressure-sensitive adhesive sheet may have a thickness of 50 to 250 μm, preferably 100 to 200 μm. When the thickness of the pressure-sensitive adhesive sheet satisfies the above range, it is preferable because the adhesive strength is excellent and the improvement of the effect according to the thickness of the pressure-sensitive adhesive sheet is maximized.

<Optical member and display device>

Another aspect of the present invention relates to an optical member comprising the above-described pressure-sensitive adhesive sheet. Specifically, the pressure-sensitive adhesive layer may be an optical pressure-sensitive adhesive film (OCA).

The optical member is, for example, a touch panel, a window, a polarizing plate, a color filter, a retardation film, an elliptically polarizing film, a reflective film, an anti-reflection film, a compensation film, a brightness enhancing film, an alignment film, a light diffusion film, a glass scattering prevention film, surface protection Transparent electrode such as film, plastic LCD substrate, indium tin oxide (ITO), fluorinated tin oxide (FTO), aluminum dopped zinc oxide (AZO), carbon nanotube (CNT), Ag nanowire, graphene, etc. A film etc. are mentioned.

The method of manufacturing the optical member may be easily manufactured by a person skilled in the art to which the present invention pertains.

Another aspect of the present invention relates to a display device including the above-described optical member. The display device is not limited thereto as long as it includes an optical member including the adhesive sheet described above, and for example, a touch panel, an OLED display, or the like may be referred to.

Hereinafter, examples will be given to describe the present specification in detail. However, the embodiments according to the present specification may be modified in various other forms, and the scope of the present specification is not to be construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely explain the present specification to those of ordinary skill in the art. In addition, "%" and "part" indicating the content hereinafter are based on weight unless otherwise specified.

manufacturing example : ( meta ) acrylate production of syrup

manufacturing example One

In a 1L reactor in which nitrogen gas is refluxed and a cooling device is installed for easy temperature control, 50 wt% of 2-ethylhexyl acrylate (2-EHA) monomer, 40 wt% of isobornyl acrylate (IBOA) monomer, and N-isobu After adding a monomer mixture composed of 10% by weight of toxymethylacrylamide (N-iBMAA) monomer, nitrogen gas was purged for 1 hour to remove oxygen, and then maintained at 80°C. After uniformly mixing the monomer mixture, when the total weight of the monomer mixture was 100 parts by weight, 0.5 parts by weight of 1-hydroxy-cyclohexyl-phenyl-ketone as a photoinitiator was added. After stirring, UV lamp (10mW) was irradiated to prepare acrylic syrup having a conversion rate of 25%.

manufacturing example 2-3

It was carried out in the same manner as in Preparation Example 1, but a (meth)acrylate syrup was prepared with the composition shown in Table 1 below.

Experimental example 1. Evaluation of weight average molecular weight and molecular weight distribution

The weight average molecular weight and molecular weight distribution of (meth)acrylate syrup were measured using GPC under the following conditions. The measurement result was converted using standard polystyrene of Agilent system for preparation of the calibration curve.

<Weight average molecular weight measurement conditions>

Meter: Agilent GPC (Agilent 1200 series, USA)

Column: 2 PL Mixed B connections

Column temperature: 40°C

Eluent: tetrahydrofuran

Flow rate: 1.0 mL/min

Concentration: ~1mg/mL (100 μl injection)

division (meth)acrylate monomer (weight %) photoinitiator
(parts by weight) polymer
conversion rate
(%) weight average
Molecular Weight
(Unit: million) EHA IBOA MA N-iBMAA DMAA 4-HBA Preparation Example 1 (A1) 50 40 - 10 - - 0.5 25 72 Preparation Example 2 (A2) 50 35 - 3 7 5 0.5 27 65 Production Example 3 (A3) 35 35 10 - 10 10 0.5 26 63 EHA: ethylhexyl acrylate
IBOA: isobornyl acrylate
MA: methyl acrylate
N-iBMAA: N-isobutoxymethylacrylamide
DMAA: dimethyl acrylamide
4-HPA: 4-hydroxybutyl acrylate
Photoinitiator: 1-Hydroxy-cyclohexyl-phenyl-ketone

Synthesis example 1(B1)

1000 g of toluene, ketoprofen (300 g, 1.18 mol), trimethylol propane (50 g, 0.37 mol) and para-toluenesulfonic acid (5.0 g) were sequentially placed in a 2 liter flask and stirred at 120° C. for 3 hours. After adding 1000 g of water to the stirred mixture, it was put into a reactor, cooled to room temperature, and stirred. After 1 hour filtration, para-toluenesulfonic acid was removed through removal of the water layer, and toluene and residual moisture were removed at high temperature/high pressure to obtain 300 g of the compound of Formula 5. The obtained product was ^{confirmed through 1} H NMR (400 MHz, CDCl ₃ , TMS) (FIG. 1).

Synthesis example 2(B2)

1000 g of toluene, ketoprofen (300 g, 1.18 mol), 4,4',4"-trihydroxytriphenylmethane (108 g, 0.37 mol) and para-toluenesulfonic acid (5.0 g) were sequentially placed in a 2 liter flask at 120 ° C. After adding 1000 g of water to the mixture, it was put into a reactor, cooled to room temperature, and stirred. After 1 hour, filtration was performed to remove para-toluenesulfonic acid through removal of the water layer, and toluene and Residual moisture was removed to obtain 300 g of the compound of Formula 6. The obtained product was ^{confirmed through 1} H NMR (400 MHz, CDCl ₃ , TMS) (FIG. 2).

Synthesis example 3 (B3)

1000 g of toluene, ketoprofen (300 g, 1.18 mol), tetrakis (2-hydroxypropyl) edylenediamine (108 g, 0.37 mol) and para-toluenesulfonic acid (5.0 g) were sequentially placed in a 2 liter flask and stirred at 120 ° C. Stirred for 3 hours. After adding 1000 g of water to the mixture, it was put into a reactor, cooled to room temperature, and stirred. After filtration for 1 hour, para-toluenesulfonic acid was removed through removal of the water layer, and 300 g of the compound of Formula 7 was obtained by removing toluene and residual moisture at high temperature/high pressure. The obtained product was ^{confirmed through 1} H NMR (400 MHz, CDCl ₃ , TMS) (FIG. 3).

Synthesis example 4 (B4)

1000 g of toluene, ketoprofen (300 g, 1.18 mol), tetraethylene glycol (107 g, 0.55 mol) and para-toluenesulfonic acid (5.0 g) were sequentially placed in a 2 liter flask and stirred at 120° C. for 3 hours. After adding 1000 g of water to the mixture, it was put into a reactor, cooled to room temperature, and stirred. After 1 hour filtration, para-toluenesulfonic acid was removed through removal of the water layer, and toluene and residual moisture were removed at high temperature/high pressure to obtain 300 g of the compound of Formula 8. The obtained product was ^{confirmed through 1} H NMR (400 MHz, CDCl ₃ , TMS) (FIG. 4).

Preparation of pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet: Example 1 to 7 and comparative example 1 to 3

A pressure-sensitive adhesive composition was prepared by mixing the contents of the (meth)acrylate syrup, photoinitiator, and ketoprofen-based compound of Preparation Example in the composition shown in Table 2 below.

The pressure-sensitive adhesive composition prepared above was applied to a thickness of 150 μm on a release film coated with a silicone release agent, a release film was bonded thereon, and first cured through a TL lamp (UVV) to prepare an adhesive sheet. The adhesive sheet prepared by primary curing was irradiated with 3000 mJ of metal halide to obtain a secondary cured adhesive sheet.

Example comparative example One 2 3 4 5 6 7 One 2 3 (meth)acrylate syrup (parts by weight) Kinds A1 A1 A1 A1 A1 A2 A3 A1 A1 A3 content 100 100 100 100 100 100 100 100 100 100 photoinitiator ¹⁾
(parts by weight) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Ketoprofen-based compounds B1 2 One 4 - - - 2 - - - B2 - - - 2 - - - - - - B3 - - - - 2 - - - - - B4 - - - - - 2 - - - - Ketoprofen - - - - - - - 2 - 2 25℃
storage modulus
(Pa, 1Hz) Primary
Hardening 1.1×10 ⁶ 1.1×10 ⁵ 1.1×10 ⁶ 1.1×10 ⁶ 1.1×10 ⁶ 8.5×10 ⁵ 7.2×10 ⁵ 1.1×10 ⁶ 1.1×10 ⁶ 7.2×10 ⁵ Secondary
Hardening 1.5×10 ⁶ 1.3×10 ⁶ 1.8×10 ⁶ 1.4×10 ⁶ 1.6×10 ⁶ 1.7×10 ⁶ 1.6×10 ⁶ 1.12×10 ⁶ 1.1×10 ⁶ 7.3×10 ⁵ durability heat-and-moisture resistance ○ ○ ◎ ○ ◎ ○ ○ × × × heat resistance ○ ○ ◎ ○ ◎ ○ ○ × × × 1)2,2-dimethoxy-1,2-diphenylethanone

Experimental example 2. Measurement of storage modulus

The storage modulus at 25° C. of each of the adhesive sheets prepared in Examples and Comparative Examples was measured using a viscoelasticity measuring device (MCR-301, manufactured by Anton Paar). The size of the adhesive sheet sample is 30mm in length × 30mm in width, and after bonding the sample to the glass substrate and adhering to the measuring tip, in the temperature range of 30-30 to 100℃, the frequency is 1.0Hz, the strain is 2%, and the temperature rises. It was measured under the condition of speed 　 5/min, and obtained by reading the measured value at 25 ° C. The results of measuring the elastic modulus of the adhesive sheet after primary curing and secondary curing are shown in Table 2 above.

Experimental example 3: Durability (heat resistance, moisture heat resistance ) evaluation

The pressure-sensitive adhesive sheet prepared by peeling the release film on one side of the pressure-sensitive adhesive sheet prepared in Examples 1 to 7 and or Comparative Examples 1 to 3 and corona-treating and bonding the 40 μm cycloolefin (COP)-based film and the pressure-sensitive adhesive sheet to 90 mm After cutting to a size of ×170 mm, peeling the release film attached to the other side, and attaching it to a glass substrate (110 mm × 190 mm × 0.7 mm) to prepare a specimen. At this time, the applied pressure was 5 kg/cm ² and a clean room operation was performed to prevent bubbles or foreign substances from being generated.

For the heat resistance property, the occurrence of bubbles or peeling was observed after leaving it for 500 hours at a temperature of 100°C. was observed. The evaluation criteria are as follows, and the results are described in Table 2 above.

<Evaluation criteria>

ⓞ: No air bubbles or partial peeling

○: Less than 5 bubbles or partial peeling

(triangle|delta): 5 or more of bubbles or partial peeling, and less than 10

×: 10 or more bubbles or partial peeling

Referring to Table 2, the pressure-sensitive adhesive sheets according to Examples 1 to 7, which satisfy the storage elastic modulus of the present invention and the storage elastic modulus increase rate after additional UV curing, have superior durability such as heat resistance and heat-and-moisture resistance than those of Comparative Examples 1 to 3 could see that

Claims (10)

The storage modulus at 25°C and 1 Hz is 5.0×10 ⁴ to 2.0×10 ⁶ Pa,
After additional UV curing, as an adhesive sheet having a storage elastic modulus increase rate of 20% or more,
The adhesive sheet,
an acrylic polymer comprising a repeating unit derived from an acryl monomer and a repeating unit derived from an acrylamide monomer containing a C1 to C20 linear, branched or alicyclic alkyl group; and
a polyfunctional ketoprofen-based compound containing two or more ketopropenyl groups represented by the following formula (1);
including,
The acrylamide monomer is an adhesive sheet comprising at least one selected from the group consisting of compounds represented by the following Chemical Formulas 2 and 3:
[Formula 1]

[Formula 2]

[Formula 3]

In Formulas 2 and 3,
R1 is each independently hydrogen or a methyl group,
R2 is each independently a C1 to C10 straight-chain or branched hydrocarbon group. According to claim 1,
Based on 100% by weight of the total acrylic polymer,
The repeating unit derived from the acrylic monomer is included in an amount of 60 to 95% by weight,
The acrylamide monomer-derived repeating unit is a pressure-sensitive adhesive sheet comprising a cured product of the pressure-sensitive adhesive composition contained in 5 to 40% by weight. delete 3. The method of claim 2,
The pressure-sensitive adhesive composition is based on 100% by weight of the total acrylic polymer,
The adhesive sheet which further comprises more than 0 and 20 weight% or less of a hydroxyl-containing monomer. 3. The method of claim 2,
The pressure-sensitive adhesive composition further comprises a photoinitiator pressure-sensitive adhesive sheet. 3. The method of claim 2,
The acrylic polymer is included in an amount of 10 to 60% by weight based on 100% by weight of the total pressure-sensitive adhesive sheet. 3. The method of claim 2,
The pressure-sensitive adhesive sheet further includes an acrylic monomer and an acrylamide monomer containing a C1 to C20 straight chain, branched chain or alicyclic alkyl group to the acrylic polymer, the C1 to C20 straight chain, branched chain or acrylic containing an alicyclic alkyl group A monomer and the acrylamide monomer constitute an acrylic syrup,
The multifunctional ketoprofen-based compound is included in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the total acrylic syrup. 8. The method of claim 7,
The photoinitiator is an adhesive sheet that is included in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the total acrylic syrup. An optical member comprising the pressure-sensitive adhesive sheet according to any one of claims 1, 2, and 4 to 8. A display device comprising the optical member according to claim 9 .

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