KR102294181B1 - Adhesive composition, adhesive sheet, optical member and image display device produced using the same - Google Patents

Abstract

The pressure-sensitive adhesive composition according to the present invention comprises a polymer block a and a polymer block b based on a (meth)acrylate unit, and a block copolymer having a Tg of -50°C to 10°C; and a urethane acrylate oligomer.
The pressure-sensitive adhesive composition according to the present invention has advantages of excellent adhesion durability, suppression of haze generation, and a low degree of cure shrinkage during curing.

Description

Adhesive composition, adhesive sheet, optical member and display device manufactured using the same {ADHESIVE COMPOSITION, ADHESIVE SHEET, OPTICAL MEMBER AND IMAGE DISPLAY DEVICE PRODUCED USING THE SAME}

The present invention relates to an adhesive composition, an adhesive sheet manufactured using the same, an optical member, 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.

On the other hand, in the case of mobile terminals such as smartphones and tablets, development of flexible displays as well as thinning and slimming are recently required for mobile terminals such as smartphones and tablets. This together is required.

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 a fused ring-containing acrylate It discloses a photocurable pressure-sensitive adhesive composition.

Korean Patent Laid-Open No. 2017-0086741 relates to a pressure-sensitive adhesive composition for a touch panel and an adhesive sheet, and includes a first resin having a weight average molecular weight of 1000 to 3000,000 and a second resin having a weight average molecular weight of 1000 to 200,000. and, each of the first resin and the second resin is an acrylic copolymer resin polymerized from a mixed monomer containing (meth)acrylate having a cyclic structure, an organic solvent, and a photoinitiator. is starting

However, the conventional pressure-sensitive adhesive composition or pressure-sensitive adhesive sheet is somewhat lacking in adhesive durability, so phenomena such as haze and curing shrinkage may occur, and thus the durability of a display device including an optical member using the pressure-sensitive adhesive composition or pressure-sensitive adhesive sheet is reduced. A problem arises.

Therefore, there is a demand for the development of an adhesive sheet having excellent adhesive durability and suppressing the occurrence of phenomena such as haze and curing shrinkage.

Republic of Korea Patent Publication No. 2016-0011785 (2016.02.02.) Republic of Korea Patent Publication No. 2017-0086741 (2017.07.27.)

An object of the present invention is to provide a pressure-sensitive adhesive composition having excellent adhesion durability such as heat resistance and heat resistance, suppression of haze generation, and a low degree of cure shrinkage.

Another object of the present invention is to provide an adhesive sheet having excellent adhesive durability and less haze, an optical member including the same, and a display device.

The present invention relates to a block copolymer comprising a polymer block a and a polymer block b based on a (meth)acrylate unit, and having a Tg of -50°C to 10°C; And urethane acrylate oligomer; provides a pressure-sensitive adhesive composition comprising a.

In addition, the present invention provides a pressure-sensitive adhesive sheet comprising a cured product of the above-described pressure-sensitive adhesive composition.

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 composition according to the present invention has advantages of excellent adhesion durability, suppression of haze generation, and a low degree of cure shrinkage during curing.

In addition, the pressure-sensitive adhesive sheet prepared from the pressure-sensitive adhesive composition according to the present invention, an optical member and a display device including the same have excellent adhesion durability and have the advantage of haze generation.

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 composition>

One aspect of the present invention is a block copolymer comprising a polymer block a and a polymer block b based on a (meth)acrylate unit, and having a Tg of -50°C to 10°C; And urethane acrylate oligomer; relates to a pressure-sensitive adhesive composition comprising a.

block copolymer

The pressure-sensitive adhesive composition according to the present invention includes a polymer block a and a polymer block b based on a (meth)acrylate unit, and includes a block copolymer having a Tg of -50°C to 10°C.

Since the pressure-sensitive adhesive composition includes a block copolymer including a polymer block a and a polymer block b based on the (meth)acrylate unit, there is an advantage that can reduce the durability defect of the pressure-sensitive adhesive according to the temperature change, Since the block copolymer has a Tg (glass transition temperature) of -50°C to 10°C, it has the advantage of securing wettability to the substrate and improving durability due to the expression of rubber-like properties.

Preferably, the block copolymer may have a Tg of -45°C to 5°C.

The glass transition temperature of the polymer composed only of (meth)acrylate units constituting the polymer block a may be greater than 50° C. and less than or equal to 180° C., and the glass transition temperature of the polymer composed only of (meth)acrylate units constituting the polymer block b. The transition temperature may be -100°C or more and 50°C or less, and the block copolymer compound may not have a liquid-gel transition temperature (Tc) between 0 and 150°C.

The (meth)acrylate unit constituting the polymer block a is a (meth)acrylate compound in which the glass transition temperature of a polymer composed only of (meth)acrylate units (hereinafter referred to as polymer a) is greater than 50° C. and not greater than 180° C. It is formed when it is polymerized. In addition, from the viewpoint of stability of the glass transition temperature, the weight average molecular weight of the polymer a is preferably 1×10 ⁵ or more, more preferably 1×10 ⁵ to 1×10 ⁹ , still more preferably 1×10 ⁵ to 1× It can be 10 or ^{7 days.}

The (meth)acrylate unit constituting the polymer block b is a (meth)acrylate having a glass transition temperature of -100°C or more and 50°C or less of a polymer composed of only (meth)acrylate units (hereinafter referred to as polymer b). Formed when compounds polymerize. In addition, from the viewpoint of stability of the glass transition temperature, the weight average molecular weight of the polymer b is preferably 1×10 ⁵ or more, more preferably 1×10 ⁵ to 1×10 ⁹ , still more preferably 1×10 ⁵ to 1×10 ^It can be 7 days.

As the (meth)acrylate compound that can constitute the polymer block a or the polymer block b, preferably methyl (meth) acrylate, ethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, or n-butyl alkyl (meth) acrylates such as (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, and lauryl (meth) acrylate;

alkoxy-substituted alkyl (meth) acrylates such as methoxyethyl (meth) acrylate;

Hydroxy-substituted alkyl (such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate) meth) acrylates;

aryl (meth) acrylates such as benzyl (meth) acrylate and phenyl (meth) acrylate;

Ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylates such as di(meth)acrylate, neopentylglycol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate;

aliphatic ring structure-containing (meth)acrylates such as dicyclopentenyloxyethyl (meth) acrylate, norbornene (meth) acrylate, dicyclopentanyl (meth) acrylate, and isobornyl (meth) acrylate; and

At least two compounds selected from the group consisting of acrylamides such as acryloyl morpholine and diethyl acrylamide, more preferably methyl methacrylate (methyl methacrylate) and n-butyl acrylate (butyl acrylamide) rate) as a structural unit of the polymer block a or the polymer block b based on the Tg shown when each compound alone constitutes the polymer.

The polymer block a is preferably composed of only (meth)acrylate units, but in the temperature range of 0 to 150° C., the block copolymer does not have a liquid-gel transition temperature (Tc), and a commercial compound described later has a liquid-gel transition temperature. As long as it has a temperature (Tc), it is a polymer structure mainly composed of (meth)acrylate units in which other copolymerizable compound units are allowed to be included.

The molar ratio of (meth)acrylate units in the polymer block a may be preferably 90 to 100 mol%, more preferably 95 to 100 mol%, still more preferably 99 to 100 mol%.

The polymer block b is preferably composed of only (meth)acrylate units, but in the temperature range of 0 to 150° C., the block copolymer does not have a liquid-gel transition temperature (Tc), and a commercial compound described later has a liquid-gel transition temperature. As long as it has a temperature (Tc), it is a polymer structure mainly composed of (meth)acrylate units, in which other copolymerizable compound units are allowed to be included.

The molar ratio of (meth)acrylate units in the polymer block b is preferably 90 to 100 mol%, more preferably 95 to 100 mol%, and still more preferably 99 to 100 mol%.

It can be understood that the polymer blocks a and b in the block copolymer have a polymerization structure almost equivalent to that of the polymers a and b, respectively, and the glass transition point of the block copolymer is in a temperature range including the glass transition points of the polymers a and b, that is, It is preferable to have a glass transition temperature in the temperature range of more than 50 degreeC and 180 degrees C or less, and the temperature range of -100 degreeC or more and 50 degrees C or less.

The adjustment conditions of the polymer a, the polymer b, and the block copolymer can be exemplified as follows.

Each of the polymer a, the polymer b, and the block copolymer was sheet-formed to a thickness of 0.5 mm at a pressure of 10 MPa using a hydraulic hot press machine manufactured by Kando Metal Industry Co., Ltd. set at 200°C. Thereafter, a strip piece of 45 mm × 10 mm × 0.5 mm required for dynamic viscoelasticity measurement is cut out.

The measurement conditions of the glass transition point may be exemplified as follows.

A dynamic viscoelasticity device (DMS6100) manufactured by Seiko Instruments can be used, and in the chart obtained by measuring under the conditions of a temperature range of -100°C to 200°C (temperature increase rate of 3°C/min) and a frequency of 11 Hz, the peak of tanδ The temperature is read and set as the glass transition point of each of the polymer a, the polymer b, and the block copolymer constituting the strip piece.

The block copolymer preferably has at least one triblock structure in which the polymer block a is bonded to both ends of the polymer block b from the viewpoint of liquid-gel transferability of the pressure-sensitive adhesive composition to be described later, and it is more preferable to have only a triblock structure. However, in the temperature range of 0 to 150 ° C., the block copolymer does not have a liquid-gel transition temperature (Tc), and the pressure-sensitive adhesive composition described later has a liquid-gel transition temperature (Tc) in a range other than the triblock structure (eg For example, a diblock structure in which the polymer block a and the polymer block b are bonded) may be included.

From the above viewpoint, the molar ratio of the triblock structure in the block copolymer may be preferably 90 to 100 mol%, more preferably 95 to 100 mol%, and still more preferably 99 to 100 mol%.

As the block copolymer, commercially available "KURARITY" (trademark, Kurares) (for example, LA2140, LA2250, LA4285, LA2330, LA3270, LA1114, LA1892, TL3320) can be used.

In addition, the block copolymer may be a block copolymer to which reactivity is imparted, but is not limited thereto. Specifically, the block copolymer is a radical reactive group, cationic reaction at the terminal or side chain of the block copolymer of the polymer block a and the polymer block b from the viewpoint of improving the elasticity and adhesiveness of the gel-type pressure-sensitive adhesive composition and the pressure-sensitive adhesive composition during curing, which will be described later. It is preferable that reactivity is imparted by having at least one reactive functional group selected from the group consisting of a sexual group, an anion-reactive group and a moisture-reactive group.

In this specification, a reactive group that polymerizes with moisture (moisture) in the air is referred to as a moisture-reactive group, and curing of the curable composition by polymerization reaction of a moisture-reactive group in the curable composition is referred to as wet curing.

From the viewpoint of improving the elasticity and tackiness of the gel-type pressure-sensitive adhesive composition and the pressure-sensitive adhesive composition upon curing, the radical reactive group is preferably (meth)acrylate, (meth)acrylamide, (meth)acrylonitrile, urethane (meth) ) may be at least one selected from the group consisting of acrylate, vinyl group, vinyl ether, allyl ether, maleimide and maleic anhydride, more preferably, (meth) acrylate, (meth) acrylamide, urethane It may be at least one radical selected from the group consisting of (meth) acrylate and vinyl ether, and more preferably, at least one radical selected from the group consisting of (meth) acrylate and urethane (meth) acrylate. It may be a reactive group.

From the viewpoint of improving the elasticity and adhesiveness of the gel-type pressure-sensitive adhesive composition and the pressure-sensitive adhesive composition during curing, the above-mentioned cation-reactive group is preferably at least one cation-reactive group selected from the group consisting of epoxy, oxetane and vinyl ether. have.

From the viewpoint of improving the elasticity and tackiness of the gel-type pressure-sensitive adhesive composition and the pressure-sensitive adhesive composition upon curing, the anion-reactive group is preferably at least one anion-reactive group selected from the group consisting of epoxy, oxetane and vinyl ether. .

From the viewpoint of improving the elasticity and tackiness of the gel-type pressure-sensitive adhesive composition and the pressure-sensitive adhesive composition upon curing, the moisture-reactive group may preferably be an isocyanate group and/or an alkoxysilyl group.

In another embodiment of the present invention, two or more types of the block copolymer may be included. More preferably, the pressure-sensitive adhesive composition according to the present invention may include two types of the first block copolymer and the second block copolymer, that is, the block copolymer.

When the pressure-sensitive adhesive composition includes the first block copolymer and the second block copolymer, the first block copolymer has a Tg of -25 to 10°C, preferably -20 to 5°C, more preferably It may be -15 to 0 °C, and the second block copolymer has a Tg of -50 to -15 °C, preferably -45 to -25 °C, more preferably -40 to -30 °C. Using a combination is preferred because it has the advantage of improving wettability and durability to the substrate.

In another embodiment of the present invention, the block copolymer may be included in 55 to 85 parts by weight, preferably 60 to 80 parts by weight, more preferably 65 to 75 parts by weight based on 100 parts by weight of the total pressure-sensitive adhesive composition. have.

When the block copolymer is included within the above range, it is preferable because wettability to the substrate and durability are improved.

urethane acrylate oligomer

Since the pressure-sensitive adhesive composition according to the present invention includes a urethane acrylate oligomer, there is an advantage in that it has excellent wettability and durability to a substrate during curing.

The urethane acrylate oligomer according to the present invention may be prepared by urethane reaction of an isocyanate compound having two or more isocyanate groups in the molecule and an acrylate compound having one or more hydroxyl groups in the molecule.

The isocyanate compound is specifically 4,4'-dicyclohexyldiisocyanate, hexamethylenediisocyanate, 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, 1,8-diisocyanatooctane, 1 ,12-diisocyanatodecane, 1,5-diisocyanato-2-methylpentane, trimethyl-1,6-diisocyanatohexane, 1,3-bis(isocyanatomethyl)cyclohexane, trans-1, 4-cyclohexene diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), isophorone diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylene-1,4- Diisocyanate, tetramethylxylene-1,3-diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis(2,6-dimethylphenylisocyanate), 4,4'-oxy Bis(phenyl isocyanate), trifunctional isocyanate derived from hexamethylene diisocyanate, trimethanol adduct toluene diisocyanate, etc. are mentioned, These can be used individually or in combination of 2 or more types.

The acrylate compound containing the hydroxyl group is specifically 2-hydroxyethyl acrylate, 2-hydroxyisopropyl acrylate, 4-hydroxybutyl acrylate, caprolactone ring-opened hydroxyacrylate, pentaerythritol tri/tetraacryl a rate mixture, a dipentaerythritol penta/hexaacrylate mixture, etc. are mentioned, These can be used individually or in combination of 2 or more types.

Specifically, the urethane acrylate oligomer may be a bifunctional urethane acrylate oligomer.

Examples of the bifunctional urethane acrylate oligomer include commercially available CN9002, CN910A70, CN9167, CN9170A86, CN9200, CN963B80, CN964A85, CN965, CN966H90, CN9761, CN9761A75, CN981, CN996, CN996 commercially available mers , UF8001G and DAUA-167 (above, public consulate), etc. can be used.

The urethane acrylate oligomer may be polymerized during curing of the pressure-sensitive adhesive composition to form a cross-linked polymer.

In another embodiment of the present invention, the urethane acrylate oligomer is included in an amount of 5 to 35 parts by weight, preferably 10 to 30 parts by weight, more preferably 15 to 25 parts by weight based on 100 parts by weight of the total pressure-sensitive adhesive composition. In this case, it is preferable because there is an advantage in that wettability and durability to the substrate are improved.

In another embodiment of the present invention, a monofunctional (meth) acrylate compound; photoinitiators; And it may further include one or more selected from the group consisting of additives.

( mat ) acrylate compound

The pressure-sensitive adhesive composition of the present invention may include a monofunctional (meth)acrylate compound.

When the pressure-sensitive adhesive composition of the present invention includes a monofunctional (meth)acrylate compound, it is preferable because there is an advantage of having sufficient wettability to the substrate.

When the (meth) acrylate compound is more than bifunctional, it may be difficult to express adhesive force due to the implementation of tack free property due to the coating film after curing. Because it contains, it is possible to implement low adhesion.

The monofunctional (meth) acrylate compound is, for example, n-butyl (meth) acrylate, 2-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) ) acrylate, 2-ethylhexyl (meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, pentyl (meth) acrylic Rate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-methylbutyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, isoamyl (meth) ) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, octadecyl (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, phenoxyethyl (meth) acrylate , tetrahydrofurfuryl (meth)acrylate, and acryloylmorpholine. These can be used individually or in mixture of 2 or more types.

The (meth)acrylate compound may include a linear or branched C4 to C20 alkyl group. When the (meth)acrylate compound includes a linear or branched C4 to C20 alkyl group, it is preferable because there is an advantage in that adhesion to the substrate is improved by improving wettability to the substrate.

The alkyl group is, for example, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, n-octyl, tert-octyl, 1-methyl Heptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 2-methylpentyl, 4-methylhexyl, 5-methylhexyl, and the like, but are not limited thereto.

Specifically, in the present invention, the (meth) acrylate compound may be lauryl acrylate or isobornyl acrylate.

The (meth)acrylate compound may be included in an amount of 3 to 20 parts by weight, preferably 5 to 15 parts by weight, more preferably 7 to 13 parts by weight, based on 100 parts by weight of the total pressure-sensitive adhesive composition. When the (meth)acrylate compound is included within the above range, it is preferable because there is sufficient wettability to the substrate.

photoinitiator

The photoinitiator is not particularly limited as long as it is commonly used in the art, for example, 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-chlorocetophenone, 4,4-dimethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4-hydroxycyclophenylketone, 1- Hydroxycyclohexylphenylketone, 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-diethyl thioxanthone, 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, hydroxycyclohexyl phenyl ketone, etc. are mentioned. In addition, as commercially available products, brand names Darocur 1173, Irgacure 184, Irgacure 907 (Ciba) and the like can also be used. These can be used individually or in combination of 2 or more types.

The photoinitiator may be included in an amount of 3.0 to 6.5 parts by weight, preferably 3.5 to 6.0 parts by weight, more preferably 4.0 to 5.5 parts by weight, based on 100 parts by weight of the pressure-sensitive adhesive composition. When the photoinitiator is included within the above range, there is an advantage in that the photoinitiation efficiency is improved.

The pressure-sensitive adhesive composition according to the present invention includes, in addition to the above components, a tackifying resin, an antioxidant, a leveling agent, a surface lubricant, an antifoaming agent, in order to control the required adhesive force, cohesive force, viscosity, elastic modulus, glass transition temperature, etc. according to the use thereof. , fillers, may further include additives such as light stabilizers.

The pressure-sensitive adhesive composition according to the present invention may be for an optically clear resin (OCR), but is not limited thereto. Specifically, since the pressure-sensitive adhesive composition according to the present invention can be used for an adhesive resin, there is an advantage that its performance is not deteriorated even when used on a flexible substrate.

<Adhesive sheet, optical member and display device>

Another aspect of the present invention relates to a pressure-sensitive adhesive sheet comprising a cured product of the above-described pressure-sensitive adhesive composition.

The pressure-sensitive adhesive sheet may be prepared by coating the pressure-sensitive adhesive composition on a release film at a temperature of about 40° C. to form an adhesive layer, and curing the pressure-sensitive adhesive layer through photocuring.

The thickness of the pressure-sensitive adhesive sheet may be 25 to 150㎛, preferably 50 to 100㎛. 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.

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

The display device may include other components that are typically included in the display device, such as a light emitting device such as a light source, a light guide plate, and an image display unit including a color filter according to the present invention, but the present invention is not limited thereto.

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.

Synthesis example : urethane acrylate Preparation of oligomers

In a 2L three-neck flask equipped with an electronic stirrer, a heating mantle, a cooling tube, and a temperature controller, a compound having a bifunctional or more functional isocyanate group in a molecule, a silicone diol having a bifunctional or more functional hydroxyl group, dibutyltin dilaurate as a catalyst ( Sigma-Aldrich Co.) was added to the composition shown in Table 1 below, and the reaction temperature was increased to 70° C. while stirring, and the reaction was maintained for 4 hours. Thereafter, (meth)acrylate having a hydroxyl group in the molecule and methoxy hydroquinone (HQ-MME, Eastman Corporation) as a polymerization inhibitor were reacted with the composition shown in Table 1 below, and the reaction was maintained for 2 hours after the addition was completed. ^{When the 2260cm -1} peak, which is a characteristic peak of NCO on FT-IR, disappeared, the reaction was terminated to prepare a silicone urethane (meth)acrylate oligomer (unit: parts by weight).

(Unit: g) Synthesis example ^{Compound 1)} having an isocyanate group 524 (H ₁₂ MDI) silicone diol 933 (A1) ²⁾ dibutyl tin dilaurate 0.4 Methoxy Hydroquinone 0.3 (meth)acrylate 232 (2-hydroxyethyl acrylate) 1) 4,4'-Methylene dicyclohexyl diisocyanate (molecular weight 262)
2) A1: X-22-160AS (Shin-Etsu, molecular weight 933)

Example and comparative example : Preparation of pressure-sensitive adhesive composition

Adhesive compositions (unit: parts by weight) according to Examples and Comparative Examples were prepared according to the configuration and composition of Table 2 below.

division urethane
acrylate
oligomer (meth)acrylate photoinitiator block copolymer A-1 A-2 B-1 B-2 B-3 B-4 Example 1 15 10 0 5 50 20 - - Example 2 25 0 10 5 30 30 - - Example 3 15 5 5 5 30 40 - - Example 4 15 10 0 5 70 - - - Comparative Example 1 40 10 5 5 - - 40 - Comparative Example 2 40 0 5 5 - - - 50 Urethane acrylate oligomer: Urethane acrylate oligomer according to Synthesis Example
A-1: Lauryl Acrylate
A-2: isobornyl acrylate
B-1: PMMA (polymethylmethacrylate) / BA (butyl acrylate) block copolymer, T _g : 10℃, TL3320 Kurariti, Kuraray Corporation
B-2: PMMA (polymethylmethacrylate) / BA (butyl acrylate) block copolymer, T _g : -35℃, LA1114 Kurarit product, Kuraray Corporation
B-3: PMMA homopolymer, T _g : 104°C
B-4: PBA homopolymer, T _g : -50℃, SY-061 product, Negami
Photoinitiator: hydroxycyclohexyl phenyl ketone

Manufacture of adhesive sheet

On a transparent film coated with a silicone release agent on a polyethylene terephthalate (PET) film, the pressure-sensitive adhesive composition was coated to a thickness of 50 μm after curing and cured by irradiating ultraviolet rays (600 mJ/cm ² ). Thereafter, an adhesive sheet was prepared by bonding the same transparent film on the pressure-sensitive adhesive layer.

test example

The physical properties of the pressure-sensitive adhesive composition and the pressure-sensitive adhesive sheet prepared in Examples and Comparative Examples were measured by the following method, and the results are shown in Table 3 below.

1. Adhesive durability (heat resistance and moist heat resistance)

The prepared adhesive film was cut to A4 size using a super cutter, and a single transparent film was peeled off and bonded to a glass plate. This conjugate was treated in an autoclave at 50° C. and 5 atm for 20 minutes to prepare a specimen. For heat resistance durability, after leaving the specimen in an oven at 80°C for 100 hours, and for moisture heat resistance after leaving it in an oven at 60°C and 90%RH for 100 hours, whether bubbles or peeling occur on the bonding surface of the glass plate and the adhesive layer was visually observed and evaluated based on the following criteria.

<Evaluation criteria>

(circle): There is no bubble and peeling phenomenon on a bonding surface.

(triangle|delta): Some bubble or peeling phenomenon exists in the bonding surface.

x: There are many bubble and peeling phenomena in a bonding surface.

2. Haze

Haze was measured by leaving the prepared pressure-sensitive adhesive sheet in an oven at -40°C and an oven at 80°C for 100 hours, respectively (equipment: HZ-02 of SUGA, Japan).

3. Cure shrinkage

The cured coating layer surface was visually checked under a fluorescent lamp in reflection mode to evaluate the degree of curing shrinkage.

<Evaluation criteria>

◎: When the degree of contraction is not seen in the reflection mode.

○: When the shape of the fluorescent light source is not constant in the reflection mode or the degree of shrinkage is weak.

×: When the degree of shrinkage is clearly seen in the reflection mode.

heat resistance Moisture and heat resistance haze
(-40℃, after 100 hours) haze
(80℃, after 100 hours) curing shrinkage Example 1 ○ ○ 0.6 0.7 ◎ Example 2 ○ ○ 0.6 0.7 ◎ Example 3 ○ ○ 0.7 0.6 ◎ Example 4 ○ ○ 0.8 0.9 ○ Comparative Example 1 - - - - - Comparative Example 2 × × 1.3 1.5 ×

Referring to Table 1, in the case of the Example according to the present invention, all of the heat resistance durability, moisture resistance durability, haze and curing shrinkage test examples showed excellent results.

On the other hand, in the case of Comparative Example, all of the heat resistance, moisture resistance, haze, and curing shrinkage test examples showed poor results. Measurement was not possible.

Claims (8)

a block copolymer comprising a polymer block a and a polymer block b based on a (meth)acrylate unit and having a Tg of -50°C to 10°C; and
An isocyanate compound, a silicone diol, and a urethane acrylate oligomer prepared by reacting an acrylate compound having a hydroxyl group in the molecule; A pressure-sensitive adhesive composition comprising:
The urethane acrylate oligomer is included in 15 to 25 parts by weight based on 100 parts by weight of the total pressure-sensitive adhesive composition, the pressure-sensitive adhesive composition. According to claim 1,
The pressure-sensitive adhesive composition comprising two or more kinds of the block copolymer. According to claim 1,
The block copolymer is included in an amount of 55 to 85 parts by weight based on 100 parts by weight of the total pressure-sensitive adhesive composition. delete According to claim 1,
monofunctional (meth)acrylate compounds; photoinitiators; And the pressure-sensitive adhesive composition further comprising one or more selected from the group consisting of additives. A pressure-sensitive adhesive sheet comprising a cured product of the pressure-sensitive adhesive composition according to any one of claims 1 to 3 and 5. An optical member comprising the adhesive sheet according to claim 6 . A display device comprising the optical member according to claim 7 .