阅读说明：本技术 用于封装有机发光二极管的组合物和包括由其形成的有机层的有机发光二极管显示器 (Composition for encapsulating organic light emitting diode and organic light emitting diode display including organic layer formed therefrom ) 是由 朴昶远 南成龙 李知娟 柳智铉 于 2021-06-02 设计创作，主要内容包括：本发明涉及一种用于封装有机发光二极管的组合物以及包含其的有机发光二极管显示器。组合物包含：含乙烯基、烯丙基或乙烯基醚基的阳离子可聚合化合物以及光酸产生剂,其中以固体含量计,相对于约100重量份的组合物,含乙烯基、烯丙基或乙烯基醚基的阳离子可聚合化合物以约95重量份到99.9重量份的量存在。(The present invention relates to a composition for encapsulating an organic light emitting diode and an organic light emitting diode display including the same. The composition comprises: a vinyl, allyl, or vinyl ether group-containing cationic polymerizable compound and a photoacid generator, wherein the vinyl, allyl, or vinyl ether group-containing cationic polymerizable compound is present in an amount of about 95 parts by weight to 99.9 parts by weight based on a solid content relative to about 100 parts by weight of the composition.)

1. A composition for encapsulating an organic light emitting diode comprising:

a cationic polymerizable compound having a vinyl group, an allyl group or a vinyl ether group and a photoacid generator,

wherein the cationic polymerizable compound containing a vinyl group, an allyl group, or a vinyl ether group is present in an amount of 95 parts by weight to 99.9 parts by weight based on a solid content relative to 100 parts by weight of the composition.

2. A composition for encapsulating an organic light emitting diode according to claim 1, wherein the vinyl, allyl or vinyl ether group containing cationically polymerizable compound comprises at least one selected from the group consisting of: a compound having an alicyclic group or an aromatic group and having at least one vinyl group, allyl group or vinyl ether group in its molecular structure, and a compound having no alicyclic group or aromatic group and having at least one vinyl group, allyl group or vinyl ether group in its molecular structure.

3. A composition for encapsulating an organic light emitting diode according to claim 2, wherein said vinyl, allyl or vinyl ether group containing cationically polymerizable compound comprises at least one selected from the group consisting of: divinylbenzene, 1, 4-cyclohexanedimethanol divinyl ether, allyl benzyl ether and 5-vinylbicyclo [2.2.1] hept-2-ene, diethylene glycol divinyl ether, 1-tetradecene, triethylene glycol divinyl ether, octadecyl vinyl ether, trimethylolpropane diallyl ether and 1, 4-butanediol divinyl ether.

4. The composition for encapsulating an organic light emitting diode according to claim 1, wherein the photoacid generator comprises at least one selected from the group consisting of: n-hydroxynaphthalimide trifluoromethanesulfonate and thio-p-phenylenebis (4,4' -dimethyldiphenylsulfonium) bis-tetrakis (pentafluorophenyl) borate.

5. The composition for encapsulating an organic light emitting diode according to claim 1, further comprising:

(meth) acrylic photocurable monomers; and

a photo radical initiator.

6. The composition for encapsulating an organic light emitting diode according to claim 1, wherein the composition has a post-cure dielectric constant of 2.9 or less than 2.9.

7. The composition for encapsulating an organic light emitting diode of claim 1, wherein the composition has a post-cure plasma etch rate of 10% or less than 10% calculated according to equation 1:

post-cure plasma etch rate (%) { (T1-T2)/T1} × 100, - - (1)

Wherein T1 indicates an initial thickness in micrometers of an organic layer obtained by depositing the composition on a silicon wafer followed by curing by light irradiation at a flux of 100 milliwatts per square centimeter for 10 seconds, and T2 indicates a thickness in micrometers of the organic layer after inductively coupled plasma processing by inductively coupled plasma chemical vapor deposition under conditions of an inductively coupled plasma power of 2,500 watts, an RE power of 300 watts, a direct current bias of 200 volts, an argon flow of 70 standard cubic centimeters per minute, an etching time of 1 minute, and a pressure of 10 millitorr.

8. An organic light emitting diode display comprising an organic layer formed from the composition for encapsulating organic light emitting diodes according to any one of claims 1 to 7.

Technical Field

The present invention relates to a composition for encapsulating an organic light emitting diode and an organic light emitting diode display including an organic layer formed therefrom. More particularly, the present invention relates to a composition for encapsulating an organic light emitting diode, which has a high light-curing rate, a low post-curing plasma etching rate, and a low post-curing dielectric constant (permittivity, epsilon), and an organic light emitting diode display including an organic layer formed therefrom.

Background

The organic light emitting diode may suffer from reliability deterioration when in contact with external moisture or oxygen. Therefore, the organic light emitting diode needs to be encapsulated with an encapsulation layer (stack of organic and inorganic layers) including organic and inorganic layers formed from a composition for encapsulating the organic light emitting diode.

The organic layer may be formed by applying a composition for encapsulating the organic light emitting diode to a predetermined thickness, followed by curing. Recently, inkjet coating is considered as a method of applying the composition. Inkjet coating allows for the dropwise deposition of the composition onto a surface through a nozzle at a predetermined temperature and a predetermined drop rate. In order to be suitable for inkjet coating, the viscosity of the composition needs to be reduced. However, the reduction in viscosity does not necessarily ensure good ink-jet coatability.

In the organic light emitting diode display, various display elements are stacked on upper and lower sides of the organic light emitting diode, except for an encapsulation layer. The organic light emitting diode is affected by electricity, static electricity, or electromagnetic waves emitted from the display element. This results in malfunction or degradation of the organic light emitting diode. Therefore, there is a need for a composition for encapsulating an organic light emitting diode, which is capable of forming an organic layer having a low dielectric constant and thus can minimize the effect of other elements stacked on the organic light emitting diode, while having a basic function of encapsulating the organic light emitting diode.

The background art of the present invention is disclosed in Korean patent laid-open publication No. 10-2016-.

Disclosure of Invention

It is an object of the present invention to provide a composition for encapsulating an organic light emitting diode, which can form an organic layer having good plasma resistance after curing.

Another object of the present invention is to provide a composition for encapsulating an organic light emitting diode, which can form an organic layer having a low dielectric constant over a wide frequency range after curing.

It is still another object of the present invention to provide a composition for encapsulating an organic light emitting diode, which has a high light curing rate and thus can form an organic layer having high light transmittance after curing.

It is yet another object of the present invention to provide a composition for encapsulating an organic light emitting diode, which has good inkjet coatability.

One aspect of the present invention relates to a composition for encapsulating an organic light emitting diode.

1. The composition for encapsulating an organic light emitting diode includes: a cationic polymerizable compound containing a vinyl, allyl, or vinyl ether group; and a photoacid generator, wherein the cationic polymerizable compound containing a vinyl group, an allyl group, or a vinyl ether group is present in an amount of about 95 parts by weight to 99.9 parts by weight, based on a solid content, relative to about 100 parts by weight of the composition.

2. In embodiment 1, the vinyl, allyl, or vinyl ether group-containing cationic polymerizable compound may comprise at least one selected from the group consisting of: a compound having an alicyclic group or an aromatic group and having at least one vinyl group, allyl group or vinyl ether group in its molecular structure, and a compound having no alicyclic group or aromatic group and having at least one vinyl group, allyl group or vinyl ether group in its molecular structure.

3. In embodiments 1 and 2, the vinyl, allyl, or vinyl ether group-containing cationic polymerizable compound may include at least one selected from the group consisting of: divinylbenzene, 1, 4-cyclohexanedimethanol divinyl ether, allyl benzyl ether and 5-vinylbicyclo [2.2.1] hept-2-ene, diethylene glycol divinyl ether, 1-tetradecene, triethylene glycol divinyl ether, octadecyl vinyl ether, trimethylolpropane diallyl ether and 1, 4-butanediol divinyl ether.

4. In embodiments 1 to 3, the photoacid generator may include at least one selected from among: n-hydroxynaphthalimide trifluoromethanesulfonate (N-hydroxynaphthalimide triflate) and thio-p-phenylenebis (4,4'-dimethyldiphenylsulfonium) bis-tetrakis (pentafluorophenyl) borate (thio-p-phenylenebis (4,4' -dimethyldiphenylsulfonium) bis-tetrakis (pentafluorophenyl) borate).

5. In examples 1-4, the composition may further comprise: (meth) acrylic photocurable monomers; and a photo radical initiator.

6. In examples 1-5, the composition may have a post-cure dielectric constant of about 2.9 or less than 2.9.

7. In embodiments 1-6, the composition may have a post-cure plasma etch rate of about 10% or less than 10%, as calculated according to equation 1:

post-cure plasma etch rate (%) { (T1-T2)/T1} × 100, - - (1)

Wherein T1 indicates the initial thickness (in: micrometers) of an organic layer obtained by depositing a composition on a silicon (Si) wafer followed by curing for 10 seconds by light irradiation at a flux of 100 mW/cm, and T2 indicates the initial thickness of an organic layer obtained by depositing a composition on a silicon (Si) wafer, and curing at an Inductively Coupled Plasma (ICP) power: 2,500 watts, RE power: 300 Watts, DC bias: 200V, Ar flow: 70 standard cubic centimeters per minute, etching time: 1 minute and pressure: the thickness (unit: μm) of the organic layer after the ICP plasma treatment by inductively coupled plasma chemical vapor deposition (ICP CVD) under the condition of 10 mtorr.

Another aspect of the present invention relates to an organic light emitting diode display comprising an organic layer formed from the composition for encapsulating an organic light emitting diode according to the present invention.

The present invention provides a composition for encapsulating an organic light emitting diode, which can form an organic layer having good plasma resistance after curing.

The present invention provides a composition for encapsulating an organic light emitting diode, which can form an organic layer having a low dielectric constant over a wide frequency range after curing.

The present invention provides a composition for encapsulating an organic light emitting diode, which has a high light curing rate and thus can form an organic layer having high light transmittance after curing.

The invention provides a composition for encapsulating an organic light emitting diode, which has good ink-jet coatability.

Drawings

Fig. 1 is a cross-sectional view of an organic light emitting diode display according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view of an organic light emitting diode display according to another embodiment of the present invention.

Description of the reference numerals

10: a substrate;

20: an organic light emitting diode;

30: barrier stacking;

31: an inorganic layer;

32: an organic layer/organic barrier layer;

40: an inner space;

100. 200: an organic light emitting display.

Detailed Description

Embodiments of the present invention will be described in detail with reference to the accompanying drawings so as to be easily implemented by those skilled in the art. It is to be understood that the present invention may be embodied in various forms and is not limited to the following embodiments. In the drawings, portions irrelevant to the description will be omitted for clarity. Throughout this specification, like components will be denoted by like reference numerals. It should be noted that the drawings are not drawn to precise scale and that lengths or sizes of components may be exaggerated for descriptive convenience and clarity only.

As used herein, the term "(meth) propenyl" may refer to "propenyl" and/or "methylpropenyl".

As used herein, unless otherwise specified, the term "substituted" means that at least one hydrogen atom of a functional group according to the present invention is substituted by: halogen (e.g. F, Cl, Br or I), hydroxy, nitro, cyano, imino (═ NH, ═ NR, R is C)₁To C₁₀Alkyl), amino (-NH)₂-NH (R '), -N (R') (R '), wherein R', R 'and R' are each independently C₁To C₁₀Alkyl), amidino, hydrazine or hydrazone groups, carboxyl groups, C₁To C₂₀Alkyl radical, C₆To C₃₀Aryl radical, C₃To C₃₀Cycloalkyl radical, C₃To C₃₀Heteroaryl or C₂To C₃₀A heterocycloalkyl group.

As used herein to represent a particular numerical range, the expression "X to Y" means "greater than or equal to X and less than or equal to Y (X ≦ and ≦ Y)".

The present invention provides a composition for encapsulating an organic light emitting diode (hereinafter, referred to as "composition") which has a high light curing rate and good ink-jettable coatability, and can form an organic layer having good plasma resistance and a low dielectric constant over a wide frequency range after curing.

In one embodiment, the composition according to the present invention can form an organic layer having a plasma etch rate of about 10% or less than 10%, specifically about 0% to 8%, as calculated according to equation 1. Within this range, damage to the organic layer when the inorganic layer is formed on the organic layer can be prevented, thereby extending the lifespan of the organic light emitting diode:

post-cure plasma etch rate (%) { (T1-T2)/T1} × 100, - - (1)

Where T1 indicates the initial thickness (in: micrometers) of an organic layer obtained by depositing a composition over a silicon (Si) wafer followed by curing by light irradiation at a flux of 100 milliwatts per square centimeter for 10 seconds, and T2 indicates the initial thickness of the organic layer obtained at an Inductively Coupled Plasma (ICP) power: 2,500 watts, RE power: 300 Watts, DC bias: 200V, Ar flow: 70 standard cubic centimeters per minute, etching time: 1 minute and pressure: thickness (unit: micrometer) of the organic layer after the ICP plasma treatment by ICP CVD under a condition of 10 mtorr.

Here, FE-SEM (Hitachi High Technologies Corporation) may be used to measure the thickness (or height) of the organic layer, but is not limited thereto.

In one embodiment, the composition according to the present invention can have a post cure dielectric constant of about 2.9 or less than 2.9 (e.g., 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, or 2.9), specifically about 1.5 to about 2.9 or about 2.0 to about 2.7). Within this range, the organic light emitting diode encapsulated using the composition may exhibit good performance without being affected by external static electricity or electricity. In particular, the composition according to the present invention forms organic layers alternately stacked with inorganic layers described below. To form organic layers with low dielectric constant and good plasma resistance in such an alternating stack structure, the composition according to the present invention is designed to have a post-cure dielectric constant of about 2.9 or less than 2.9.

In one embodiment, the photocuring rate of a composition according to the present invention can be evaluated by measuring the post-cure hardness (e.g., pencil hardness) of the composition. For details of the hardness measurement, reference is made to the experimental examples described below. The composition according to the invention may have a post-cure hardness of H or greater than H. Within this range, the composition may have a high light curing rate, and thus may improve the lifespan and reliability of the organic light emitting diode when used for an organic layer of the organic light emitting diode. Preferably, the composition according to the invention has a post-cure hardness of H to 3H. Within this range, the composition may improve the lifespan and reliability of the organic light emitting diode due to its high light curing rate, while reducing the dielectric constant of the organic layer.

The compositions according to the invention have a post-cure dielectric constant over a wide frequency range within the ranges specified herein. For example, compositions according to the present invention may have a post-cure dielectric constant of about 2.9 or less than 2.9 at frequencies of about 200 kilohertz to about 1 gigahertz (e.g., about 200 kilohertz to about 500 kilohertz).

In one embodiment, the composition according to the present invention may have good inkjet coatability. Here, the inkjet coating means that the composition is applied using an inkjet printer under the conditions of a drop rate of about 2.5 to about 3.5 microns/second and a head temperature of about 20 to 50 ℃.

The composition according to one embodiment of the present invention comprises a vinyl, allyl or vinyl ether group-containing cationically polymerizable compound and a photoacid generator, wherein the vinyl, allyl or vinyl ether group-containing cationically polymerizable compound is present in an amount of about 95 to 99.9 parts by weight (e.g., 95.0 parts by weight, 95.1 parts by weight, 95.2 parts by weight, 95.3 parts by weight, 95.4 parts by weight, 95.5 parts by weight, 95.6 parts by weight, 95.7 parts by weight, 95.8 parts by weight, 95.9 parts by weight, 96.0 parts by weight, 96.1 parts by weight, 96.2 parts by weight, 96.3 parts by weight, 96.4 parts by weight, 96.5 parts by weight, 96.6 parts by weight, 96.7 parts by weight, 96.8 parts by weight, 96.9 parts by weight, 97.0 parts by weight, 97.1 parts by weight, 97.2 parts by weight, 97.3 parts by weight, 97.4 parts by weight, 97.5 parts by weight, 97.7.8 parts by weight, 97.8 parts by weight, 97.9 parts by weight, 97.0 parts by weight, or more part by weight, relative to about 100 parts by weight of the composition based on a solid content, 98.0 parts by weight, 98.1 parts by weight, 98.2 parts by weight, 98.3 parts by weight, 98.4 parts by weight, 98.5 parts by weight, 98.6 parts by weight, 98.7 parts by weight, 98.8 parts by weight, 98.9 parts by weight, 99.0 parts by weight, 99.1 parts by weight, 99.2 parts by weight, 99.3 parts by weight, 99.4 parts by weight, 99.5 parts by weight, 99.6 parts by weight, 99.7 parts by weight, 99.8 parts by weight, or 99.9 parts by weight). Within this range, the composition may have a high light curing rate and good inkjet coatability, and may form an organic layer having good plasma resistance and a low dielectric constant at a wide frequency range after curing. Preferably, the vinyl, allyl, or vinyl ether group-containing cationic polymerizable compound may be present in an amount of about 97 parts by weight to 99.9 parts by weight, based on the solid content, relative to about 100 parts by weight of the composition.

Now, each component of the composition according to the present invention will be described in detail.

Cationically polymerizable compounds containing vinyl, allyl or vinyl ether groups

When present within the ranges specified herein, the vinyl, allyl, or vinyl ether group-containing cationically polymerizable compound increases the photocuring rate of the composition and decreases the dielectric constant of the organic layer obtained by curing the composition.

The vinyl, allyl, or vinyl ether group-containing cationic polymerizable compound may comprise at least one selected from the group consisting of: a compound having an alicyclic group or an aromatic group and having at least one (preferably 1 to 2) vinyl group, allyl group or vinyl ether group in its molecular structure, and a compound having no alicyclic group or aromatic group and having at least one (preferably 1 to 2) vinyl group, allyl group or vinyl ether group in its molecular structure. These compounds may be used alone or in the form of a mixture thereof in a composition.

In the compound having an alicyclic group or aromatic group and having at least one (preferably 1 to 2) vinyl group, allyl group or vinyl ether group in its molecular structure, the alicyclic group means C composed of only carbon atoms not containing oxygen₅To C₁₀A cyclic functional group. The compound having an alicyclic group or an aromatic group and having at least one (preferably 1 to 2) vinyl group may include at least one selected from the group consisting of: divinyl benzene (including 1, 2-divinyl benzene, 1, 3-divinyl benzene, 1, 4-divinyl benzene and combinations thereof), 1, 4-cyclohexanedimethanol divinyl ether, allyl benzyl ether and 5-vinyl bicyclo [2.2.1]Hept-2-ene.

The compound which does not contain an alicyclic group or an aromatic group and has at least one (preferably 1 to 2) vinyl group, allyl group or vinyl ether group in its molecular structure may comprise at least one selected from the group consisting of: diethylene glycol divinyl ether, 1-tetradecene, triethylene glycol divinyl ether, octadecyl vinyl ether, trimethylolpropane diallyl ether, and 1, 4-butanediol divinyl ether.

In one embodiment, the vinyl, allyl, or vinyl ether group-containing cationically polymerizable compound can comprise at least one selected from the group consisting of: divinylbenzene (including 1, 2-divinylbenzene, 1, 3-divinylbenzene, 1, 4-divinylbenzene, and combinations thereof), 1-tetradecene, diethylene glycol divinyl ether, 1, 4-cyclohexanedimethanol divinyl ether, allyl benzyl ether, and combinations thereof.

Photoacid generators

The photoacid generator is used to photocure a cationic polymerizable compound containing a vinyl, allyl, or vinyl ether group to form an organic layer.

The photoacid generator is a compound that induces curing of a cationically polymerizable compound by generating a cationic species upon receiving light, and may include a cationic moiety that absorbs light and an anionic moiety that serves as a source of acid.

The photoacid generator may comprise at least one selected from the group consisting of: sulfonate compounds, sulfonium compounds, diazonium salt compounds, iodonium salt compounds, sulfonium salt compounds, phosphonium salt compounds, selenium salt compounds, oxonium salt compounds, ammonium salt compounds, and bromine salt compounds. For example, the photoacid generator can comprise at least one selected from the group consisting of: n-hydroxynaphthalimide trifluoromethanesulfonate, thio-p-phenylenebis (4,4' -dimethyldiphenylsulfonium) bis-tetrakis (pentafluorophenyl) borate, (4-hydroxyphenyl) methylbenzylsulfonium tetrakis (pentafluorophenyl) borate, 4- (4-biphenylthio) phenyl-4-biphenylphenylsulfinatotetrakis (pentafluorophenyl) borate, 4- (phenylthio) phenyldiphenylsulfonium phenyltris (pentafluorophenyl) borate, [4- (4-biphenylthio) phenyl-4-biphenylphenylsulfinatotetrakis (pentafluorophenyl) borate, diphenyl [4- (phenylthio) phenylsulfinato ] hexafluoroantimonate, diphenyl [4- (phenylthio) phenyl ] sulfonium tris (pentafluoroethyl) trifluorophosphate, diphenyl [4- (phenylthio) phenyl ] sulfonium tetrakis (pentafluorophenyl) borate, and mixtures thereof, Diphenyl [4- (phenylthio) phenyl ] sulfonium hexafluorophosphate, 4- (4-biphenylthio) phenyl-4-biphenylphenylsulfonium tris (pentafluoroethyl) trifluorophosphate, bis [4- (diphenylsulfonium) phenyl ] sulfophenyl tris (pentafluorophenyl) borate, and [4- (2-thianthrenylthio) phenyl ] phenyl-2-thianthrenylsulfonium (pentafluorophenyl) borate, but not limited thereto.

Preferably, the photoacid generator comprises at least one selected from the group consisting of: n-hydroxynaphthalimide trifluoromethanesulfonate, and thio-p-phenylenebis (4,4' -dimethyldiphenylsulfonium) bis-tetrakis (pentafluorophenyl) borate.

The photoacid generator may be present in an amount of 0.1 to 5 parts by weight, preferably 0.1 to 3 parts by weight, based on the solid content, relative to 100 parts by weight of the composition. Within this range, the vinyl, allyl, or vinyl ether group-containing cationic polymerizable compound can have a high curing rate while preventing a decrease in light transmittance of the organic layer due to the residue of the photoacid generator.

The composition may further comprise a (meth) acrylic photocurable monomer.

(meth) acrylic acid photocurable monomer

The (meth) acrylic photocurable monomer may form an organic layer by curing. When the (meth) acrylic photocurable monomer is present in the composition in an appropriate amount such that the amount of the vinyl, allyl, or vinyl ether group-containing cationically polymerizable compound falls within the range specified herein, the composition according to the present invention can have a low post-cure dielectric constant and good inkjet coatability.

The (meth) acrylic photocurable monomer may be present in an amount of 50 parts by weight or less than 50 parts by weight, specifically about 10 parts by weight to 28 parts by weight, based on the solid content, relative to about 100 parts by weight of the composition. Within this range, the composition can have an increased photocuring rate, thereby allowing an organic layer formed from the composition to have an increased hardness and a dielectric constant within the ranges specified herein, while having good inkjet coatability.

The (meth) acrylic photocurable monomer may include a photocurable monomer having at least one (meth) acrylate group.

In one embodiment, the (meth) acrylic photocurable monomer may comprise at least one selected from the group consisting of: containing C₁To C₁₅Alkyl mono (meth) acrylates and C-containing₆To C₁₅Alkylene di (meth) acrylates.

Containing C₁To C₁₅The mono (meth) acrylate of an alkyl group may comprise at least one selected from the group consisting of: hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, and dodecyl (meth) acrylate (lauryl (meth) acrylate).

Containing C₆To C₁₅The di (meth) acrylate of the alkylene group may comprise C having a substitution or an unsubstituted, preferably an unsubstituted, between the (meth) acrylate groups₆To C₁₅Alkylene di (meth) acrylates. For example, di (meth) acrylates may be represented by formula 1:

(wherein R is₁₀And R₁₁Each independently is hydrogen or methyl and R₁₂Is substituted or unsubstituted C₆To C₁₅Alkylene).

For example, in formula 1, R₁₂May be unsubstituted C₆To C₁₂An alkylene group. The di (meth) acrylate may comprise at least one selected from the group consisting of: 1, 6-hexanediol di (meth) acrylate, 1, 8-octanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, 1, 10-decanediol di (meth) acrylate, 1, 11-undecanediol di (meth) acrylate, and 1, 12-dodecanediol di (meth) acrylate.

The composition may further comprise a photo radical initiator.

Photo-radical initiator

The photo radical initiator may include any typical photo radical initiator that can initiate photo curing of the (meth) acrylic photo-curable monomer. For example, the photo radical initiator may comprise a triazine initiator, an acetophenone initiator, a benzophenone initiator, a thioxanthone initiator, a benzoin initiator, a phosphorous initiator, an oxime initiator, or mixtures thereof.

Examples of phosphorus initiators may include diphenyl (2,4, 6-trimethylbenzoyl) phosphine oxide, benzyl (diphenyl) phosphine oxide, or mixtures thereof. The phosphorescent radical initiator is advantageously used to initiate photocuring of the composition upon irradiation with long wavelength UV. The aforementioned photo radical initiators may be used alone or in combination thereof.

The photo radical initiator may be present in an amount of 0.5 to 7 parts by weight, specifically 1 to 5 parts by weight or 2 to 4 parts by weight, based on the solid content, relative to 100 parts by weight of the composition. Within this range, the composition can be sufficiently cured upon exposure to light while preventing the organic layer from being lowered in light transmittance due to the residue of the photo radical initiator.

The composition according to the invention can be prepared by mixing the aforementioned components. Further, the composition according to the present invention may be formed in a solvent-free type without any solvent.

The composition according to the present invention is a photocurable composition and can be cured into an encapsulation layer (organic layer) by UV irradiation at a flux of 10 to 500 mw/cm for 1 to 50 seconds.

The composition according to the invention may further comprise typical additives known to the person skilled in the art. Examples of the additive may include a heat stabilizer, an antioxidant, and a UV absorber, but are not limited thereto.

The composition according to the invention can be used for encapsulating organic light-emitting diodes. In particular, the composition may form an organic layer in an encapsulation structure, wherein the organic layer and the inorganic layer are formed sequentially over each other.

For example, compositions according to the present invention can be used to encapsulate components of an apparatus (particularly, components of a display) that would otherwise suffer degradation or failure due to permeation of ambient gases or liquids (e.g., atmospheric oxygen and/or moisture and/or water vapor) and due to permeation of chemicals used to manufacture electronic products. Examples of components of an apparatus may include, but are not limited to, lamps, metal sensing pads, microdisk lasers, electrochromic devices, photochromic devices, microelectromechanical systems, solar cells, integrated circuits, charge coupled devices, and light emitting polymers.

The organic light emitting diode display according to the present invention may include an organic layer formed of the composition for encapsulating an organic light emitting diode according to an embodiment of the present invention. In particular, an organic light emitting diode display may include an organic light emitting diode and a barrier stack formed on the organic light emitting diode and including an inorganic layer and an organic layer, wherein the organic layer may be formed of the composition for encapsulating the organic light emitting diode according to an embodiment of the present invention. Accordingly, the organic light emitting display may have high reliability.

Now, an organic light emitting diode display according to an embodiment of the present invention will be described with reference to fig. 1. Fig. 1 is a cross-sectional view of an organic light emitting diode display according to an embodiment of the present invention.

Referring to fig. 1, an organic light emitting display 100 according to this embodiment may include a substrate 10, an organic light emitting diode 20 formed on the substrate 10, and a barrier stack 30 formed on the organic light emitting diode 20 and including an inorganic layer 31 and an organic layer 32, wherein the inorganic layer 31 abuts the organic light emitting diode 20, and the organic layer 32 may be formed of a composition for encapsulating an organic light emitting diode according to an embodiment of the present invention.

The substrate 10 is not particularly limited as long as the organic light emitting diode can be formed thereon. For example, the substrate 10 may include a transparent glass substrate, a plastic sheet substrate, a silicon substrate, a metal substrate, and the like.

The organic light emitting diode 20 may comprise any organic light emitting diode commonly used in organic light emitting diode displays. Although not shown in fig. 1, the organic light emitting diode 20 may include a first electrode, a second electrode, and an organic light emitting layer formed between the first and second electrodes. Here, the organic light emitting layer may have a structure in which a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer are sequentially stacked, but is not limited thereto.

The barrier stack 30 includes an organic layer and an inorganic layer, wherein the organic layer and the inorganic layer are formed of different materials, thereby accomplishing the respective functions of encapsulating the organic light emitting diode.

The inorganic layer may be formed of a different material than the organic layer to complement the encapsulation provided by the organic layer. For example, the inorganic layer may comprise a metal; a non-metal; a compound or alloy of at least two metals; a compound or alloy of at least two non-metals; oxides of metals or non-metals; metal or non-metal fluorides; metal or non-metal nitrides; carbides of metals or non-metals; metallic or non-metallic nitrogen oxides; a metal or non-metal boride; boron oxides of metals or non-metals; metal or non-metal silicides; and mixtures thereof. The metal or nonmetal may include, but is not limited to, silicon (Si), aluminum (Al), selenium (Se), zinc (Zn), antimony (Sb), indium (In), germanium (Ge), tin (Sn), bismuth (Bi), transition metals, and lanthanide metals. Specifically, the inorganic layer may be silicon oxide (SiO)_x) Silicon nitride (SiN)_x) Silicon oxynitride (SiO)_xN_y) Zinc selenide (ZnSe), zinc oxide (ZnO), antimony trioxide (Sb)₂O₃) Comprising aluminum oxide (Al)₂O₃) Aluminum oxide (AlO)_x) Indium oxide (In)₂O₃) Or tin oxide (SnO)₂)。

The inorganic layer may be deposited by a plasma process or a vacuum process, such as sputtering, chemical vapor deposition, plasma chemical vapor deposition, evaporation, sublimation, electron cyclotron resonance-plasma enhanced chemical vapor deposition, or a combination thereof.

The organic layers are alternately deposited with the inorganic layers, thereby ensuring the smooth properties of the inorganic barrier layers while preventing the defects of one inorganic layer from diffusing to the other inorganic layers.

The organic layer may be formed by a combination of coating, deposition, and curing of the composition for encapsulating the organic light emitting diode according to an embodiment of the present invention. For example, the organic layer may be formed by: the composition is applied to a thickness of about 1 micron to about 50 microns and subsequently cured by light irradiation at a flux of about 10 milliwatts per square centimeter to about 500 milliwatts per square centimeter for about 1 second to 50 seconds.

The barrier stack may include any number of organic and inorganic layers. The total number of organic and inorganic layers may vary depending on the desired level of permeation resistance to oxygen and/or moisture and/or chemicals. For example, the organic and inorganic layers are formed in a total of 10 layers or less than 10 layers, such as 2 to 7 layers. Specifically, the organic layer and the inorganic layer were formed in the following order with a total of 7 layers: inorganic layer/organic layer/inorganic barrier layer.

In the barrier stack, organic barrier layers and inorganic barrier layers may be alternately deposited. This is based on considering the benefits of the organic layer due to the aforementioned attributes of the composition. Thus, the organic and inorganic layers may complement or reinforce each other with respect to the components of the encapsulation device.

Next, an organic light emitting diode display according to another embodiment of the present invention will be described with reference to fig. 2. Fig. 2 is a cross-sectional view of an organic light emitting diode display according to another embodiment of the present invention.

Referring to fig. 2, an organic light emitting diode display 200 according to this embodiment includes a substrate 10, an organic light emitting diode 20 formed on the substrate 10, and a barrier stack 30 formed on the organic light emitting diode 20 and including an inorganic layer 31 and an organic layer 32, wherein the inorganic layer 31 is encapsulated in an inner space 40 in which the organic light emitting diode 20 is received, and the organic barrier layer 32 may be formed of a composition for encapsulating an organic light emitting diode according to an embodiment of the present invention. The organic light emitting display 200 according to this embodiment is substantially the same as the organic light emitting display according to the above embodiment except that the inorganic layer is not adjacent to the organic light emitting diode.

Next, the present invention will be described in more detail with reference to some examples. It should be understood that these examples are provided for illustration only, and should not be construed as limiting the invention in any way.

The details of the components used in the examples and comparative examples are as follows:

a: cationically polymerizable compounds containing vinyl, allyl or vinyl ether groups

A1: mixtures of 1, 3-divinylbenzene with 1, 4-divinylbenzene (TCI)

A2: 1-tetradecene (Aldrich Chemical Co., Inc.)

A3: diethylene glycol divinyl ether (Aldrich chemical Co.)

A4: 1, 4-cyclohexanedimethanol divinyl ether (Aldrich chemical Co., Ltd.)

A5: allyl benzyl ether

B: (meth) acrylic acid photocurable monomer

B1: 1, 12-Dodecanediol diacrylate (Sartomer Co., Inc.)

C: photoacid generators

C1: TR-PAG-21608 (thio-p-phenylene-bis (4,4' -dimethyldiphenylsulfonium) bis-tetrakis (pentafluorophenyl) borate, pioneer electronics Co., Ltd.)

C2: MIPHOTO NIT (n-hydroxynaphthalimide trifluoromethanesulfonate, Miwon Corporation, Inc.)

D: photo-radical initiator

D1: brilliant solid TPO (phosphorus initiator, BASF Corporation)

Example 1

99.9 parts by weight of (A1) and 0.1 part by weight of (C1) were put in a 125 ml brown polypropylene bottle, followed by mixing in a shaker at room temperature for 3 hours, to thereby prepare a composition.

Examples 2 to 10 and comparative examples 1 to 5

Compositions were prepared in the same manner as in example 1, except that the types and/or contents of (a), (B), (C), and (D) were changed as listed in table 1 (unit: parts by weight). In table 1, "-" means that the corresponding component was not used.

The details of the compositions prepared in the examples and comparative examples are shown in table 1.

TABLE 1

Each of the compositions prepared in the examples and comparative examples was evaluated with respect to the following attributes. The results are shown in table 2.

(1) Hardness of organic layer: each of the compositions prepared in examples and comparative examples was coated on a glass substrate, followed by curing by UV irradiation at a wavelength of 395 nm at a flux of 100 milliwatts/square centimeter for 10 seconds, thereby preparing an organic layer sample. The pencil hardness was measured on the prepared organic layer sample. In the measurement of pencil hardness, an electric pencil hardness tester (Lab-Q D300A) and pencils of 6B to 9H (Mitsubishi co., Ltd.) were used. Specifically, the pencil hardness was measured under load conditions on the specimen: 500 grams, scratch angle: 45 °, and scratch rate: 48 mm/min. When the sample had one or more scratches after 5 tests using a certain pencil, the pencil hardness was measured again using another pencil having a one-step lower pencil hardness than the previous pencil. The pencil hardness value that allowed no scratch observed on all five times of the sample was taken as the pencil hardness of the sample.

(2) Plasma etching rate of organic layer (unit:%): each of the compositions prepared in examples and comparative examples was deposited on a Si wafer, followed by curing by UV irradiation at a wavelength of 395 nm at a flux of 100 mw/cm for 10 seconds, thereby forming an organic layer. Next, the initial thickness (T1, unit: micrometer) of the formed organic layer was measured. Then, at ICP power: 2,500 watts, RE power: 300 Watts, DC bias: 200V, Ar flow: 70 standard cubic centimeters per minute, etching time: 1 minute and pressure: the organic layer was subjected to ICP plasma treatment using an ICP-CVD apparatus (BMR technique) under a condition of 10 mtorr, and then the thickness of the organic layer was measured (T2, unit: μm). The plasma etch rate of the organic layer was calculated according to equation 1:

post-cure etch rate (%) { (T1-T2)/T1} × 100.

(3) Dielectric constant: each of the compositions prepared in examples and comparative examples was coated to a predetermined thickness on a chromium (Cr) plate, followed by curing for 10 seconds by UV irradiation at a wavelength of 395 nm at a flux of 100 milliwatts/square centimeter, thereby forming a coating film 8 μm thick. An aluminum electrode (electrode for measuring dielectric constant) was deposited on the paint film, and then the dielectric constant of the paint film was measured using an impedance meter (RDMS-200) at 200 kilohertz and 25 ℃.

TABLE 2

In table 2, "-" means that the corresponding composition failed to cure, and thus measurement of hardness, plasma etching rate, and dielectric constant was not possible.

As shown in table 2, the composition for encapsulating an organic light emitting diode according to the present invention has high post-cure hardness and thus high light-curing rate, and can form an organic layer having high light transmittance, good plasma resistance, and a low dielectric constant after curing.

In contrast, the compositions of comparative examples 1 to 3 (which do not contain a vinyl, allyl, or vinyl ether group-containing cationic polymerizable compound and a photoacid generator) and the compositions of comparative examples 4 to 5 (which contain a vinyl, allyl, or vinyl ether group-containing cationic polymerizable compound and a photoacid generator, but contain a vinyl, allyl, or vinyl ether group-containing cationic polymerizable compound in an amount outside the range set forth herein (about 95 parts by weight to about 99.9 parts by weight relative to about 100 parts of the composition) fail to achieve all of the benefits of the present invention.

It is to be understood that various modifications, changes, alterations, and equivalent embodiments may be made by those skilled in the art without departing from the spirit and scope of the present invention.