KR102062174B1 - Adhesive composition, adhesive sheet, optical member and image display device produced using the same - Google Patents

Abstract

Pressure-sensitive adhesive composition according to the invention is an acrylic polymer; And at least one or more diluent monomers, wherein the content of the photolytic photopolymerization initiator is 0.6% by weight or less based on 100% by weight of the total composition, and the number of bubbles according to the following evaluation method is 1.0 / cm ² or less.
[Evaluation method of bubble occurrence number]
Bonding 100 μm-thick PET (7 cm × 7 cm) to both sides of the pressure-sensitive adhesive sheet (5 cm × 5 cm, thickness 100 μm) formed of the pressure-sensitive adhesive composition, and autoclaving at 50 ° C./5 atm for 20 minutes, followed by an optical microscope Visually analyze the measured image to see the number of bubbles per unit area.
The pressure-sensitive adhesive composition according to the present invention has the advantage that the pressure-sensitive adhesive sheet can be produced with a small number of bubbles generated per unit area.

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, input devices used in combination of various types of display devices such as liquid crystal displays (LCDs) with touch panels and the like have been widely used. For example, a touch panel is provided in a mobile terminal such as a smartphone or a tablet.

In manufacture of such a display apparatus, an input apparatus, etc., the optical adhesive sheet (OCA; optically clear adhesive) is used for the purpose of bonding various optical members. In detail, 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.

In general, the adhesive sheet is bonded to an optical member such as a window cover glass, and then subjected to a high-temperature, high-pressure autoclave process in order to further increase the adhesion with the member (substrate). Therefore, the pressure-sensitive adhesive sheet should be free from lifting or peeling even when exposed to harsh conditions such as high temperature, high humidity or high temperature, high pressure conditions, etc. at the same time as adhesion to various substrates, and the generation of bubbles and the like should be suppressed.

Republic of Korea Patent Publication No. 2016-0076974 relates to a pressure-sensitive adhesive film and a display member comprising the same, a monomer mixture comprising a (meth) acrylate and a comonomer having a hydroxyl group; formed of a pressure-sensitive adhesive composition comprising, The recovery force (%) by 40% to 99%, and the bubble generation area (%) by the measuring method is disclosed for the pressure-sensitive adhesive film 0%.

However, in the case of the above document, the measurement of bubble generation area is made under moisture-resistant heat conditions, and has suitable physical properties as an adhesive composition capable of suppressing bubble generation even when exposed to harsh conditions of high temperature and high pressure of a thick film pressure-sensitive adhesive of 50 µm or more. It is not there.

Therefore, development of the adhesive composition which can manufacture the adhesive sheet which suppresses generation | occurrence | production of a bubble even when exposed to the severe conditions of the high temperature and high pressure of a thick film adhesive of 50 micrometers or more is calculated | required.

Republic of Korea Patent Publication No. 2016-0076974 (2016.07.01.)

An object of the present invention is to provide a pressure-sensitive adhesive composition capable of producing a pressure-sensitive adhesive sheet having a low number of bubble generation, particularly a number of bubble generation after autoclave treatment.

In addition, the present invention is to provide a pressure-sensitive adhesive sheet having a small bubble per unit area, an optical member and a display device including the same.

The present invention is an acrylic polymer; And at least one or more dilution monomers, wherein the content of the photodegradable photopolymerization initiator is 0.6% by weight or less based on 100% by weight of the composition, and the number of bubbles is 1.0 / cm ² or less according to the following evaluation method.

[Evaluation method of bubble occurrence number]

Bonding 100 μm-thick PET (7 cm × 7 cm) to both sides of the pressure-sensitive adhesive sheet (5 cm × 5 cm, thickness 100 μm) formed of the pressure-sensitive adhesive composition, and autoclaving at 50 ° C./5 atm for 20 minutes, followed by an optical microscope Visually analyze the measured image to see the number of bubbles per unit area.

Moreover, this invention provides the adhesive sheet containing the hardened | cured material of the adhesive composition mentioned above.

In addition, the present invention provides an optical member including the adhesive sheet described above.

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

After the pressure-sensitive adhesive composition autoclave treatment according to the present invention there is an advantage that the production of pressure-sensitive adhesive sheet with a small number of bubbles per unit area.

In addition, the pressure-sensitive adhesive sheet according to the present invention has an advantage that the number of bubbles per unit area is small, the optical member and the display device including the above-described pressure-sensitive adhesive sheet is also excellent in durability.

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

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

In the present invention, when a part "includes" a certain component, this means that it may further include other components, without excluding the other components unless otherwise stated.

<Adhesive Composition>

One aspect of the invention is an acrylic polymer; And at least one or more dilution monomers, wherein the content of the photodegradable photopolymerization initiator is 0.6% by weight or less based on 100% by weight of the total composition, and the number of bubbles according to the following evaluation method is 1.0 / cm ² or less.

[Evaluation method of bubble occurrence number]

Bonding 100 μm-thick PET (7 cm × 7 cm) to both sides of the pressure-sensitive adhesive sheet (5 cm × 5 cm, thickness 100 μm) formed of the pressure-sensitive adhesive composition, and autoclaving at 50 ° C./5 atm for 20 minutes, followed by an optical microscope Visually analyze the measured image to see the number of bubbles per unit area.

In the present invention, "bubble" may be referred to as a diameter of several hundred micrometers or less, specifically tens to hundreds of micrometers, more specifically 50 to 500nm. The "diameter" is a value indicating the particle size, that is, the size of the bubble, and may mean the length value of the longest line among the lines passing through the center of the bubble, and a measuring method used in the art may be used. For example, it may be measured using an optical profiler, a scanning electron microscope (SEM), or the like.

Although not wishing to be bound by theory, when the adhesive sheet is autoclaved at a high temperature and high pressure, for example, 50 ° C./5 atm, moisture, volatile compounds, and decomposition products of photodegradable photopolymerization initiators present in the adhesive sheet Release occurs in the state, and released gas causes bubbles. In addition, during the process of returning to normal temperature and atmospheric pressure after the autoclave treatment, bubbles are induced by external gases penetrating into the adhesive sheet, and in particular, more volatile substances act as a plasticizer in the adhesive to facilitate the penetration of air into the cross section. .

Bubbles generated in this way may cause problems such as deterioration of visibility and durability, but the pressure-sensitive adhesive composition according to the present invention occurs after the autoclave treatment because the content of the photodegradable photopolymerization initiator is 0.6% by weight or less based on 100% by weight of the total composition. There is an advantage that the number of bubbles made is very small.

Specifically, the number of bubble generation may be 0.5 / cm ² or less.

The acrylic polymer is not limited thereto, but may be polymerized using, for example, a (meth) acrylic monomer.

Specifically, the (meth) acrylic monomers are n-butyl (meth) acrylate, 2-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylic Latex, cyclohexyl (meth) acrylate), N-vinylpyrrolidone, 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 Elate, 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) a Relate, 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, tetraperfuryl (meth) acrylate, tetrahydrofuryl (meth) acrylic Monofunctional monomers such as acrylate and acryloyl morpholine; 1,3-butanedioldi (meth) acrylate, 1,4-butanedioldi (meth) acrylate, 1,6-hexanedioldi (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, 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 Dicyclopentanyldi (meth) acrylate, caprolactone modified dicyclopentenyldi (meth) acrylate, ethylene oxide modified phosphate di (meth) acrylate, bis (2-hydroxyethyl) isocyanurate di ( Meta) acrylate , Di (acryloxyethyl) isocyanurate, allylated cyclohexyldi (meth) acrylate, dimethyloldicyclopentanediacrylate, ethylene oxide modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol acrylate, neo Difunctional monomers such as pentyl glycol modified trimethylolpropanediacrylate and adamantanediacrylate; Trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified trimethylolpropane tri (meth) acrylate, propylene oxide modified trimethylolpropane tree 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, ditrimethylolpropane tetra (meth) acrylate, and tetramethylolpropane tetra (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 acrylic polymer may have a weight average molecular weight of 300,000 to 800,000, preferably 50 to 700,000. When the weight average molecular weight of the acrylic polymer is in the above range, it is preferable because there is an advantage that it is easy to adjust the viscosity required when coating the pressure-sensitive adhesive composition.

In another embodiment of the present invention, the acrylic polymer may be included in 10 to 50% by weight, preferably 20 to 40% by weight relative to the total 100% by weight of the pressure-sensitive adhesive composition. When the acrylic polymer is included in the above range, the cohesive force of the pressure-sensitive adhesive composition is maximized, and even under conditions of high temperature and high humidity, the moisture permeability is small, and thus the pressure-sensitive adhesive composition having excellent durability can be manufactured.

The polymerization method of the said acrylic polymer is not limited in this invention. When the acrylic polymer is polymerized with a thermal initiator, the thermal initiator may include, but is not limited to, one or more peroxide compounds and one or more azo compounds.

The azo compounds include 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2,4-dimethylvalle Ronitrile) and 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) and the like, and the peroxide compound is 2,5-dimethyl-2,5-di (tert-butylperoxy) -hexane, dicumyl peroxide, di (tert-butylperoxy-isopropyl) -benzene and the like can be used, but the content is not limited in the present invention.

When the acrylic polymer is polymerized using a photopolymerization initiator, the sum of the content of the photopolymerization initiator used in the polymerization and the content of the photopolymerization initiator included in the pressure-sensitive adhesive composition to be described later is 0.6% by weight or less based on 100% by weight of the total pressure-sensitive adhesive composition. .

In the pressure-sensitive adhesive composition according to the present invention, the content of the photodegradable photopolymerization initiator is 0.6% by weight or less, preferably 0.5% by weight or less based on 100% by weight of the total composition.

The photolysis type photopolymerization initiator is, 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-chronolo Cetophenone, 4,4-dimethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4-hydroxycyclophenylketone, 1-hydroxycyclohexylphenylketone, 2-methyl -1- [4- (methylthio) phenyl] -2-morpholino-propane-1-one, oligo [2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propane On], 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4-diaminobenzophenone, 4,4'- Diethylaminobenzophenone, dichlorobenzophenone, anthraqui , 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2, 4-dimethyl thioxanthone, 2,4-diethyl thioxanthone, benzyldimethyl ketal, diphenyl ketone benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoic acid ester, 2,4,6-trimethylbenzoyldiphenyl Phosphine oxide (TPO), fluorene, triphenylamine, carbazole and the like. These may be used alone or in combination of two or more.

Since the pressure-sensitive adhesive composition according to the present invention has a content of photodegradable photopolymerization initiator of 0.6% by weight or less with respect to 100% by weight of the total composition, there is an advantage that a pressure-sensitive adhesive sheet having a bubble number of 1.0 / cm ² or less can be produced.

In the present invention, the dilution monomer is a component that can make coating easy by providing durability to the pressure-sensitive adhesive composition and maintaining the storage modulus, and diluting the solvent-free pressure-sensitive adhesive composition to adjust the viscosity.

The dilution monomer may specifically be a (meth) acrylic monomer, and the (meth) acrylic monomer may be applied to the above-described contents.

The diluent monomer may be included 50 to 90% by weight, preferably 60 to 80% by weight relative to the total 100% by weight of the pressure-sensitive adhesive composition, in this case it is preferable because there is an advantage that can be easily adjusted to the viscosity required when coating the pressure-sensitive adhesive composition Do.

Pressure-sensitive adhesive composition according to the invention the acrylic polymer; And it may be formed by further adding a photolysis-type photopolymerization initiator to the acrylic syrup containing at least one dilution monomer. Specifically, the pressure-sensitive adhesive composition may be formed by adding a photopolymerization initiator to an acrylic syrup in which a (meth) acrylic monomer, an acrylic polymer which is a polymer thereof, and a diluting monomer are dissolved, but is not limited thereto.

The pressure-sensitive adhesive composition may further include a thiol-based molecular weight regulator. The thiol-based molecular weight modifier may promote termination and initiation of chain growth during radical polymerization of the acrylic compound, 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 higher polyfunctional thiol molecular weight regulator can be used.

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

The pressure-sensitive adhesive composition may further include additional agents within a range in which the above-described photocuring properties are not degraded. For example, a solvent, a silane coupling agent, a light stabilizer, an antifoamer, and a filler. Components such as lubricants, surfactants, corrosion inhibitors and the like may be appropriately included depending on the characteristics of the object.

<Adhesive sheet>

Another aspect of this invention relates to the adhesive sheet containing the hardened | cured material of the adhesive composition mentioned above.

In another embodiment of the present invention, the pressure-sensitive adhesive sheet has a bubble count of 1.0 piece / cm ² or less by the following evaluation method.

[Evaluation method of bubble occurrence number]

100 μm thick PET (7 cm × 7 cm) was bonded to both sides of the adhesive sheet (5 cm × 5 cm, thickness 100 μm), autoclaved at 50 ° C./5 atm for 20 minutes, and then measured using an optical microscope. The image is visually analyzed to determine the number of bubbles per unit area.

The pressure-sensitive adhesive sheet according to the present invention has an advantage of excellent visibility because the number of bubbles per unit area is 1.0 pieces / cm ² or less.

The manufacturing method of the said adhesive sheet is not specifically limited. For example, the pressure-sensitive adhesive sheet may be used to apply the pressure-sensitive adhesive composition on a single release film by a known coating method such as a bar coder, air knife, gravure, reverse roll, kiss roll, spray, blade, die coater, casting, spin coating, or the like. After coating using the method, the remaining one release film can be bonded, and then formed by photopolymerization curing.

<Optical member and display device>

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

The optical member may be, for example, a touch panel, a window, a polarizing plate, a color filter, a retardation film, an elliptical polarizing film, a reflective film, an antireflection film, a compensation film, a brightness enhancement film, an alignment film, a light diffusion film, a glass scattering prevention film, and a surface protection film. Transparent electrodes such as films, plastic LCD substrates, indium tin oxide (ITO), fluorinated tin oxide (FTO), aluminum dopped zinc oxide (AZO), carbon nanotube (CNT), Ag nanowires, and graphene A film etc. are mentioned.

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

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

Hereinafter, the present invention will be described in detail with reference to Examples. However, the embodiments according to the present disclosure may be modified in various other forms, and the scope of the present specification is not to be interpreted as being limited to the embodiments described below. The embodiments of the present specification are provided to more fully describe the present specification to those skilled in the art. In addition, "%" and "part" which show content below are a basis of weight unless there is particular notice.

Production Example : ( Meta ) Acrylate  Preparation of Syrup

Production Example  One.

50 wt% of 2-ethylhexyl acrylate (2-EHA) monomer, 30 wt% of isobornyl acrylate (IBOA) monomer, N-part in a 1 L reactor equipped with a refrigeration system to allow nitrogen gas to be refluxed and for easy temperature control. After adding a monomer mixture consisting of 10% by weight of methoxymethylacrylamide (NBMAA) and 10% by weight of 5-hydroxypentylacrylate (5-HPA) monomer, purging nitrogen gas for 1 hour to remove oxygen. After that, the temperature was maintained at 80 ° C. After uniformly mixing the monomer mixture, when the total weight of the monomer mixture was 100 parts by weight, 0.25 parts by weight of 1-hydroxy-cyclohexyl-phenyl-ketone was added as a photoinitiator. After stirring, using a UV lamp (15mW), by irradiation with UV to prepare an acrylic syrup of 25% polymer conversion.

Production Example  2 to 5

To carry out the same as in Preparation Example 1, to prepare a (meth) acrylate syrup in the composition of Table 1.

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

The weight average molecular weight and molecular weight distribution of the (meth) acrylate syrups prepared in Preparation Examples 1 to 5 were measured under the following conditions using GPC. At this time, in the preparation of the calibration curve, the measurement results were converted using standard polystyrene of Agilent system, and the results are shown in Table 1 below.

 <Weight average molecular weight measurement conditions>

Meter: Agilent GPC (Agilent 1200 series, USA)

Column: Connect 2 PL Mixed B

Column temperature: 40 ℃

Eluent: tetrahydrofuran

Flow rate: 1.0mL / min

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

division (Meth) acrylate monomer (% by weight) Photolysis Type Photopolymerization Initiator
(Parts by weight) Polymer
Conversion rate
(%) Weight average
Molecular Weight
(Unit: only) 2-EHA IBOA NBMAA 4-HCMA 5-HPA Preparation Example 1 (A1) 50 30 10 - 10 0.25 25 53 Preparation Example 2 (A2) 50 30 20 - - 0.25 26 60 Preparation Example 3 (A3) 50 30 5 15 - 0.25 25 62 Preparation Example 4 (A4) 50 30 10 10 - 0.25 25 65 Preparation Example 5 (A5) 50 30 10 - 10 0.5 25 53 2-EHA: 2-ethylhexyl acrylate
IBOA: Isobonylacrylate
NBMAA: N-butoxymethylacrylamide
4-HCMA: 4-hydroxymethylcyclohexylmethylacrylate
5-HPA: 5-hydroxypentylacrylate
Photolysis type photopolymerization initiator: 1-hydroxy cyclohexylphenyl ketone

Example  1 to 4 and Comparative example  1 to 3.

The pressure-sensitive adhesive composition was prepared by mixing the contents of the (meth) acrylate syrup and the photolysis-type photopolymerization initiator prepared in the above preparation in the composition of Table 2 below.

The pressure-sensitive adhesive composition prepared above was applied to a release film coated with a silicone release agent to have a thickness of 150 μm, and then bonded to the release film thereon to irradiate UV lamps (10 mW / cm ² based on UVA and 400 mJ / cm ² ). The sheet was produced.

Example Comparative example One 2 3 4 One 2 3 (Meth) acrylate syrup (weight part) Kinds A1 A2 A3 A4 A1 A1 A5 content 100 100 100 100 100 100 100 Photolysis Type Photopolymerization Initiator
(Part by weight) ¹⁾ 0.25 0.3 0.3 0.25 0.5 1.0 0.25 Number of bubbles / cm ² 0.21 0.35 0.23 0.4 1.45 2.52 2.11 Durability (85 ℃, 85%) ○ ○ Ⓞ ○ △ × × 1) 2,2-dimethoxy-2-phenylacetophenone

Experimental Example  2. Number of bubble occurrence

100 μm thick PET (7 cm × 7 cm) was bonded to both surfaces of the adhesive sheets (5 cm × 5 cm, 150 μm thick) prepared in Examples and Comparative Examples, and then autoclaved at 50 ° C./5 atm for 20 minutes. The image measured using a microscope (Optical Microscope, manufactured by Olympus) was visually analyzed to confirm the number of bubbles per unit area, and the results are shown in Table 2 above.

Experimental Example  3: durability evaluation

Peeling the release film on one side of the adhesive sheet prepared in Examples and Comparative Examples, and cut the adhesive sheet prepared by corona treatment and bonding to a 40㎛ cycloolefin (COP) -based film and the adhesive surface to a size of 90 mm × 170 mm The release film attached to the other side was peeled off and then attached to a glass substrate (110 mm × 190 mm × 0.7 mm) to prepare a specimen. At this time, the applied pressure was 5kg / cm ² and the clean room operation was performed so that no bubbles or foreign matter.

After leaving for 100 hours at a temperature of 85 ° C. and a condition of 85% RH, it was observed whether bubbles or partial peeling occurred. Evaluation criteria are as follows, and the results are shown in Table 2 above.

<Evaluation Criteria>

◎: no bubble or partial peeling

○: less than 5 bubbles or partial peeling

△: 5 or more bubbles or partial peeling, less than 10

×: 10 or more bubbles or partial peelings

Referring to Table 2, Examples 1 to 4 of the total photodegradable photopolymerization initiator content of the present invention is 0.6% by weight or less based on 100% by weight of the total composition, Comparative Example 1 in which the photodegradable photopolymerization initiator content exceeds 0.6% by weight. From 3 to 3, the number of bubbles after the heating and pressing process is less than 1.0 / cm ² or less, it can be seen that the durability is excellent.

Claims (7)

Acrylic polymers;
At least one (meth) acrylic diluent monomer; And
As an adhesive composition containing a photolysis type | mold photoinitiator,
The content of the photolysis-type photopolymerization initiator is 0.25 to 0.55 wt% based on 100 wt% of the total composition,
Pressure-sensitive adhesive composition having a bubble number of 0.5 pieces / cm ² or less by the following evaluation method:
[Evaluation method of bubble occurrence number]
Bonding 100 μm-thick PET (7 cm × 7 cm) to both sides of the pressure-sensitive adhesive sheet (5 cm × 5 cm, thickness 100 μm) formed of the pressure-sensitive adhesive composition, and autoclaving at 50 ° C./5 atm for 20 minutes, followed by an optical microscope Visually analyze the measured image to see the number of bubbles per unit area. The method of claim 1,
The acrylic polymer is a pressure-sensitive adhesive composition comprising 10 to 50% by weight relative to the total 100% by weight of the pressure-sensitive adhesive composition. The method of claim 1,
The dilution monomer is an adhesive composition comprising 50 to 90% by weight relative to the total 100% by weight of the pressure-sensitive adhesive composition. The adhesive sheet containing the hardened | cured material of the adhesive composition of any one of Claims 1-3. The method of claim 4, wherein
The pressure-sensitive adhesive sheet is the pressure-sensitive adhesive sheet is the number of bubbles by the following evaluation method is 0.5 / cm ² or less:
[Evaluation method of bubble occurrence number]
100 μm-thick PET (7 cm × 7 cm) was bonded to both sides of the adhesive sheet (5 cm × 5 cm, thickness 100 μm), autoclaved at 50 ° C./5 atm for 20 minutes, and then measured using an optical microscope. The image is visually analyzed to determine the number of bubbles per unit area. An optical member comprising the adhesive sheet according to claim 5. A display device comprising the optical member according to claim 6.