KR102329317B1 - Adhesive sheet, optical member and display device using the same - Google Patents

Abstract

The pressure-sensitive adhesive sheet according to the present invention has an average peeling force of 20N/25mm or more when the pressure-sensitive adhesive sheet is attached to one side of the alkali-free tempered glass at 180 degrees at a rate of 0.3 m/min and the pressure-sensitive adhesive sheet is peeled off, and 100 mm It is characterized in that the minimum value (a)/maximum value (b) of the adhesion force of the adhesive sheet in the 50 mm to 80 mm section during peeling is 0.8 or more.
When the pressure-sensitive adhesive sheet according to the present invention is applied to alkali-free tempered glass, it is possible to maximize the performance expression of alkali-free tempered glass, and has excellent adhesion and peeling power. In addition, there is an advantage in that there is little variation in peeling force and uniform adhesion is maintained.

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.

Meanwhile, in the case of mobile terminals such as smartphones and tablets, development of flexible displays as well as thinning and slimming are required. In the case of such a flexible display, in order to prevent damage to the touch panel or liquid crystal module from external impact, alkali-free tempered glass is used.

Korean Patent Application Laid-Open No. 2016-0011785 relates to a photocurable pressure-sensitive adhesive composition and an adhesive film, and includes an acrylic photocurable resin formed by polymerization of a monomer component including two different (meth)acrylic ester monomers, and the two types One of the (meth)acrylic ester monomers is a tackifying monomer, and the tackifying monomer is a C6-C20 alicyclic condensed ring or fused ring-containing acrylate It discloses a photocurable pressure-sensitive adhesive composition.

However, in the case of the conventional pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet as described in the above literature, the adhesive force and peeling force required for durability expression of the alkali-free reinforced glass are not satisfied.

Therefore, there is a demand for the development of a pressure-sensitive adhesive sheet that satisfies the adhesion and peeling force required for durability of alkali-free reinforced glass, and particularly maintains excellent adhesion uniformly.

Republic of Korea Patent Publication No. 2016-0011785 (2016.02.02.)

The present invention is to solve the above problems, and an object of the present invention is to provide an adhesive sheet applicable to alkali-free reinforced glass.

In addition, an object of the present invention is to provide an adhesive sheet having excellent adhesion and peeling strength, and having less variation and uniform performance, an optical member including the same, and a display device.

In the present invention for achieving the above object, after attaching the surface of the adhesive sheet to one side of the alkali-free tempered glass, the average peeling force is 20N/25mm or more when the adhesive sheet is peeled off at 180 degrees at a speed of 0.3 m/min and , provides an adhesive sheet in which the minimum value (a) of the adhesive force / the maximum value (b) of the adhesive force of the adhesive sheet in the 50mm to 80mm section during peeling by 100mm is 0.8 or more.

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.

When the pressure-sensitive adhesive sheet according to the present invention is applied to the alkali-free tempered glass, it is possible to maximize the performance of the alkali-free tempered glass.

In addition, the pressure-sensitive adhesive sheet according to the present invention has the advantage of excellent adhesion and peeling force.

In addition, the pressure-sensitive adhesive sheet according to the present invention has an advantage in that there is little variation in peeling force and uniform adhesion is maintained.

In addition, the optical member and the display device including the pressure-sensitive adhesive sheet according to the present invention has an advantage of excellent durability.

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 is present 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>

In one aspect of the present invention, after attaching the surface of the pressure-sensitive adhesive sheet to one side of the alkali-free tempered glass, when the pressure-sensitive adhesive sheet is peeled off at 180 degrees at a rate of 0.3 m/min, the average peel force is 20N/25mm or more, and 100 It relates to a pressure-sensitive adhesive sheet having a minimum value (a)/maximum value (b) of adhesion of the pressure-sensitive adhesive sheet in the range of 50 mm to 80 mm during peeling by mm of 0.8 or more.

The pressure-sensitive adhesive sheet according to the present invention may have an average peeling force of 20N/25mm or more, preferably 25N/25mm or more, more preferably 30N/25mm or more when peeled at 180 degrees at a rate of 0.3/min.

The average peel force is an average value after measuring the peel force of three samples of the pressure-sensitive adhesive sheet.

Specifically, the peeling force was measured by peeling the release film on one side of the pressure-sensitive adhesive sheet, corona-treating the 38 μm-thick PET film and the pressure-sensitive adhesive side, and then cutting it to have a width of 25 mm and a length of 200 mm to prepare a specimen. Then, peel the release film attached to the PET/adhesive layer composition, and attach the adhesive sheet to one side of the alkali-free tempered glass using a 2 kg roller according to the regulations of JIS Z 0237, and then autoclave (50℃, 5 Atmospheric pressure) for about 20 minutes, and using an autograph (AG-1S, SHIMADZU) for a sample stored for 1 hour under constant temperature and humidity conditions (23°C, 50%RH), alkali-free reinforcement of the adhesive sheet Measurement can be performed while peeling 100 mm from the glass at a peeling rate of 0.3 m/min and a peeling angle of 180 degrees.

Since the pressure-sensitive adhesive sheet has an average peeling force of 20 N/25 mm or more, when bending, twisting, or torsional stress is applied, that is, the adhesive sheet is excellent in ease of peeling at the moment the stress is applied. In addition, it is excellent in warpage adhesion, and when bending, twisting, or torsion stress is applied to the product to which the optical member is attached and fixed, the optical member is prevented from peeling off, thereby preventing deterioration of reliability of the product.

The pressure-sensitive adhesive sheet according to the present invention has a minimum value (a)/maximum value (b) of adhesion of the pressure-sensitive adhesive sheet in a range of 50 mm to 80 mm while peeling by 100 mm is 0.8 or more, preferably 0.85 or more, more preferably 0.9 can be more than

Even if the adhesion or peeling force of the pressure-sensitive adhesive sheet is partially excellent, if the deviation thereof is large, it may cause a problem in durability of a member or product to which the pressure-sensitive adhesive sheet is applied.

The pressure-sensitive adhesive sheet according to the present invention satisfies the above range by the ratio of the maximum value to the minimum value of the adhesion force of the pressure-sensitive adhesive sheet in the 50mm to 80mm section during peeling by 100mm. Specifically, the pressure-sensitive adhesive sheet according to the present invention has the advantage that excellent durability can be imparted to products such as a member or a display device to which the pressure-sensitive adhesive sheet is applied because excellent adhesion is uniformly maintained.

The “adhesion force” refers to the degree of adhesion of the pressure-sensitive adhesive sheet to the alkali-free reinforced glass, and may be measured under the same conditions as the method for measuring the peel force.

In the present invention, "alkali-free tempered glass" refers to glass substantially free of alkali metal oxides such as _{Na 2} O and K _{2 O.} In this case, "substantially free" may mean not containing unavoidable impurities except for unavoidable impurities. The alkali-free tempered glass may be, for example, Gorilla Glass manufactured by Corning.

In one embodiment of the present invention, the pressure-sensitive adhesive sheet, C6 to C10 linear, branched or alicyclic alkyl group containing a repeating unit derived from an acrylic monomer and an acrylamide monomer derived from an acrylic polymer comprising; and, based on 100% by weight of the total acrylic polymer, the repeating unit derived from the acrylic monomer is included in 80 to 95% by weight, and the repeating unit derived from the acrylamide monomer is included in 5 to 20% by weight, and The acrylamide monomer may include a cured product of the pressure-sensitive adhesive composition including at least one selected from the group consisting of compounds represented by the following Chemical Formulas 1 and 2.

[Formula 1]

[Formula 2]

In Formulas 1 and 2,

R1 is each independently hydrogen or a methyl group,

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

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, etc. are mentioned.

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 may play a role in expressing adhesion by increasing wettability when bonding with an adherend, that is, alkali-free reinforced glass while present in the acrylic polymer.

The repeating unit derived from the acrylic monomer may be included in an amount of 80 to 95% by weight, preferably 83 to 92% by weight, more preferably 85 to 90% by weight, based on 100% by weight of the total acrylic polymer.

Specifically, the acrylic polymer can 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 adhesive sheet has excellent adhesion and reliability. have.

When the acrylic polymer is included in the pressure-sensitive adhesive composition, there is an advantage in that it is possible to manufacture a sheet having an appropriate storage modulus. Specifically, it is preferable because the elastic modulus is too high, and the adhesion with the adherend is somewhat lowered to suppress a phenomenon in which durability is difficult to develop, and the elastic modulus is too low to suppress a phenomenon in which durability is difficult due to lack of cohesive force, which is preferable.

The acrylamide monomer may include at least one selected from the group consisting of compounds represented by the following Chemical Formulas 1 and 2.

[Formula 1]

[Formula 2]

In Formulas 1 and 2,

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 is included, there is an advantage in that the adhesion to the alkali-free reinforced glass is excellent, and the adhesion is uniformly maintained.

The repeating unit derived from the acrylamide monomer is included in an amount of 5 to 20% by weight, preferably 8 to 17% by weight, more preferably 10 to 15% 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 of excellent moisture permeability even at a low moisture content. In particular, even when applied to a curved panel, there is an advantage of excellent heat-and-moisture resistance, and there is an advantage of excellent cohesion by maximizing intramolecular hydrogen bonding and chelating bonding with residual ions.

In one embodiment of the present invention, based on 100% by weight of the total acrylic polymer, the amount of the hydroxyl group-containing monomer is more than 0 and 10% by weight or less, preferably 2 to 8% by weight, more preferably 4 to 6% by weight. may include

When the hydroxyl group-containing monomer is further included, there is an advantage in that the water resistance of the pressure-sensitive adhesive sheet is excellent.

In another embodiment of the present invention, the acrylic polymer may be included in an amount of 5 to 30% by weight, preferably 10 to 27% by weight, more preferably 20 to 25% by weight based on 100% by weight of the total pressure-sensitive adhesive composition. have. When the acrylic polymer is included within the above range, the cohesive force of the pressure-sensitive adhesive composition is maximized, and the chelating bond with the adherend is excellent, thereby having excellent durability.

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

The photoinitiator may specifically be a free radical photoinitiator. The free radical photoinitiator serves to sufficiently advance the internal and surface curing of the pressure-sensitive adhesive sheet formed of the pressure-sensitive adhesive composition, and the type thereof is not particularly limited as long as it is known in the art.

Specific examples of the free radical photoinitiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, hydroxydimethylacetophenone , dimethylaminoacetophenone, dimethoxy-2-phenylacetophenone, 3-methylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 4-chloro Nolocetophenone, 4,4-dimethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4-hydroxycyclophenyl ketone, 1-hydroxycyclohexylphenyl ketone, 2- methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, Benzophenone, p-phenylbenzophenone, 4,4-diaminobenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2- t-Butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone Tone, benzyl dimethyl ketal, diphenyl ketone benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoic acid ester, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, fluorene, triphenylamine, carbazole and the like. In addition, as commercially available products, trade names Darocur 1173, Igacure 184, Igacure 907, Igacure-1700 (Ciba), etc. can be used. These can be used individually or in combination of 2 or more types.

In another embodiment of the present invention, the photoinitiator may be included in an amount of 0.01 to 3% by weight, preferably 0.1 to 2% by weight, more preferably 0.5 to 1% by weight based on 100% by weight of the total weight of the pressure-sensitive adhesive 　 composition. .

When the photoinitiator is included within the above range, there is an advantage of excellent durability due to excellent internal and surface curing of the pressure-sensitive adhesive sheet formed of the pressure-sensitive adhesive composition.

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.

In the present invention, the pressure-sensitive adhesive composition may include acrylic syrup. The acrylic syrup is a resin syrup in which a repeating unit derived from an acrylic monomer, a repeating unit derived from an amide monomer, and an acrylic polymer that is a polymer thereof are dissolved. can play a role in making

A photoinitiator may be added to the acrylic syrup to form a pressure-sensitive adhesive composition, and a pressure-sensitive adhesive sheet may be prepared by applying the pressure-sensitive adhesive composition on a release film.

Since the pressure-sensitive adhesive sheet according to the present invention satisfies the minimum value (a) of the specific average peel force and the adhesion force / the maximum value (b) of the adhesion force, it is possible to maximize the durability of the alkali-free tempered glass, specifically the bent alkali-free tempered glass. there is an advantage Specifically, the pressure-sensitive adhesive sheet according to the present invention has excellent adhesion and peeling strength, and since the deviation of the average values of the adhesion and peeling force is small, the durability of various optical members or products to which the pressure-sensitive adhesive sheet is applied is excellent.

A method of manufacturing the pressure-sensitive adhesive sheet is not particularly limited, and may be manufactured by a conventional method. For example, it can be prepared by applying the pressure-sensitive adhesive composition to one surface of the substrate and then curing. In this case, the coating method is not particularly limited, and for example, various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater may be used.

The thickness of the pressure-sensitive adhesive sheet may be 50 to 200㎛, preferably 100 to 150㎛. When the thickness of the pressure-sensitive adhesive sheet satisfies the above range, it is preferable because the adhesion 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 in the following are based on weight unless otherwise specified.

manufacturing example : ( meta ) acrylate production of syrup

manufacturing example One

45 wt% of 2-ethylhexyl acrylate (2-EHA) monomer, 45 wt% of isobornyl acrylate (IBOA) monomer, N-( After adding a monomer mixture composed of 10 wt% of isobutoxymethyl) acrylamide, 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 (meth)acrylate syrup (A1) having a conversion rate of 25%.

manufacturing example 2 to 5

It was carried out in the same manner as in Preparation Example 1, but (meth)acrylate syrups (A2 to A5) were 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. A standard polystyrene of Agilent system was used for preparation of a calibration curve, and the measurement result was converted.

<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 NIBMAA 5-HPA Preparation Example 1 (A1) 45 45 10 - 0.5 25 58 Preparation Example 2 (A2) 45 40 10 5 0.5 27 67 Production Example 3 (A3) 42 40 18 - 0.5 25 57 Production Example 4 (A4) 60 10 30 - 0.5 26 69 Production Example 5 (A5) 20 56 24 - 0.5 26 70 2-EHA: 2-ethylhexyl acrylate
IBOA: isobornyl acrylate
NIBMAA: N-(isobutoxymethyl)acrylamide
5-HPA: 5-hydroxypentyl acrylate
Photoinitiator: 1-Hydroxy-cyclohexyl-phenyl-ketone

Example 1 to 3 and comparative example 1 to 2

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

The pressure-sensitive adhesive composition prepared above is applied to a thickness of 150 μm on a release film coated with a silicone release agent, and a release film is bonded thereon to produce an adhesive sheet, and then the UV (400 mJ, UVV standard) irradiation conditions are adjusted to adjust the sheet. was completed.

Example comparative example One 2 3 One 2 (meth)acrylate syrup Kinds A1 A2 A3 A4 A5 content 100 100 100 100 100 photoinitiator
(parts by weight) I-651 0.5 0.5 0.5 0.5 0.5 storage modulus
(MPa, 1Hz) 25℃ 1.4 1.0 2.3 0.2 3.9 I-651: 2,2-dimethoxy-1,2-diphenylethanone

Experimental example 2. viscoelastic (Storage Modulus) Measurement

The storage modulus of the adhesive sheet was measured by using a viscoelasticity measuring device (MCR-301, manufactured by Anton Paar) at 25°C. More specifically, set the sample size of the adhesive layer to 30mm in length × 30mm in width, and attach the measurement sample to the glass plate and attach it to the measuring tip. It measured under the conditions of temperature increase rate = 5 degree-C/min, and calculated|required by reading the measured value of 25 degreeC. The measurement results of storage modulus after UV curing are shown in Table 2 above.

Experimental example 3. peel force and adhesion evaluation

The release film on one side of the pressure-sensitive adhesive sheet prepared in Examples or Comparative Examples was peeled off, corona-treated and bonded to a PET film of 38 μm and the pressure-sensitive adhesive side, and then cut to a width of 25 mm and a length of 200 mm to prepare a specimen. Next, peel the release film attached to the PET/adhesive layer configuration, and attach the adhesive sheet to the alkali-free tempered glass using a 2 kg roller according to the regulations of JIS Z 0237, and then autoclave (50°C, 5 atmospheres) Using an autograph (AG-1S, SHIMADZU) for a sample that was pressed for about 20 minutes in The average peel force was measured while peeling 100 mm at a peeling rate of 0.3 m/min and a peeling angle of 180 degrees, and the minimum value of adhesion (a) / maximum value of adhesion (b) was calculated, and the results are shown in Table 3 below. .

Experimental example 4. Durability (heat resistance, moisture heat resistance ) evaluation

The adhesive sheet prepared by peeling the release film on one side of the pressure-sensitive adhesive sheets prepared in Examples 1 to 3 and Comparative Examples 1 to 2 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.

The heat resistance property was observed whether bubbles or peeling occurred after leaving it for 500 hours at a temperature of 80°C, and the moisture and heat resistance property was left for 500 hours under the conditions of a temperature of 60°C and 93%RH, and the occurrence of bubbles or partial peeling. was observed. The evaluation criteria are as follows, and the results are shown in Table 3 below.

<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 air bubbles or partial peeling

Example comparative example One 2 3 One 2 Average Peel Force (N/25mm) 23 34 27 34 16 Minimum value of adhesion (a) / Maximum value of adhesion (b) 0.94 0.88 0.86 0.75 0.78 durability heat resistance ⓞ ○ ○ × × moisture heat resistance ⓞ ○ ○ ○ ○

As can be seen from Table 3, it can be seen that the pressure-sensitive adhesive sheet according to the present invention has excellent durability, whereas the sample having a large deviation between the minimum and maximum values of adhesion has weak durability.

Claims (9)

After attaching the surface of the adhesive sheet to one side of the alkali-free tempered glass, the average peeling force is 20N/25mm or more when the adhesive sheet is peeled off at 180 degrees at a speed of 0.3m/min, and 50mm to 80mm while peeling by 100mm As an adhesive sheet in which the minimum value (a) / maximum value (b) of the adhesive force of the adhesive sheet in the section is 0.8 or more,
The pressure-sensitive adhesive sheet includes a cured product of a pressure-sensitive adhesive composition comprising a; do,
The acrylic polymer is contained in an amount of 5 to 30% by weight based on 100% by weight of the total pressure-sensitive adhesive composition. 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 80 to 95% by weight,
The repeating unit derived from the acrylamide monomer is included in an amount of 5 to 20% by weight,
The acrylamide monomer is an adhesive sheet comprising at least one selected from the group consisting of compounds represented by the following formulas 1 and 2:
[Formula 1]

[Formula 2]

In Formulas 1 and 2,
R1 is each independently hydrogen or a methyl group,
R2 is each independently a C1 to C10 straight-chain or branched hydrocarbon group. 3. The method of claim 2,
Based on 100% by weight of the total acrylic polymer,
The adhesive sheet which further comprises more than 0 and 10 weight% or less of a hydroxyl-containing monomer. According to claim 1,
The pressure-sensitive adhesive composition is a pressure-sensitive adhesive sheet further comprising a photoinitiator. delete 5. The method of claim 4,
The photoinitiator is an adhesive sheet comprising 0.01 to 3% by weight based on 100% by weight of the total pressure-sensitive adhesive composition. According to claim 1,
The pressure-sensitive adhesive sheet has a thickness of 50 to 200㎛. An optical member comprising the pressure-sensitive adhesive sheet according to any one of claims 1 to 4, 6, and 7. A display device comprising the optical member according to claim 8 .