KR20090107108A - Curable Resin Composition and Organic Light Emitting Display Having the Same - Google Patents

Abstract

PURPOSE: A curable resin composition is provided to increase lifetime of an organic elestroluminescent display device by lowering water permeability. CONSTITUTION: A curable resin composition includes an alicyclic epoxy resin, bisphenol-based epoxy resin, cation photopolymerization initiator and photo-sensitizer. The photo-sensitizer is represented by chemical formula 1, wherein R is propoxy or butoxy. The organic elestroluminescent display device includes a lower plate glass, an upper plate glass, and an encapsulating material.

Description

Curable resin composition and organic electroluminescent display including same {Curable Resin Composition and Organic Light Emitting Display Having the Same}

The present invention relates to a curable resin composition comprising a photosensitizer (Formula 1), by using a photosensitizer to reduce the outgas, lowering the moisture permeability curable resin composition that can increase the device life of the organic light emitting display device It is about.

Organic EL devices have the advantages of self-luminous, wide viewing angle, and thin film type, and thus are attracting attention as next-generation displays. However, in general, organic EL devices have a disadvantage of shortening their life due to rapid aging due to moisture and outgas.

In order to overcome this drawback, the conventional method fabricated an element on a glass lower plate, coated a photocurable sealant on the edge portion, adsorbed an absorbent on the glass upper plate, and bonded the upper and lower plate glass to produce an organic EL device.

However, the moisture permeability of the rim sealant is higher than that required for the organic EL device, and thus there is a problem of shortening the life of the device due to the penetration of moisture into the sealant part.

In recent years, the organic electroluminescent element of the top emission method is attracting attention in the conventional back emission method. Unlike the bottom emission method, the top emission method has a high aperture ratio and a low voltage drive, which is advantageous in terms of long life.

In the front emission method, a method of using a transparent absorbent is known, but the transparent absorbent absorbs moisture and has a disadvantage in that transmittance is lowered. In order to compensate for these disadvantages, a method of bonding the top glass to the front surface by applying a transparent adhesive has emerged.

As described above, in order to apply the transparent adhesive to the entire surface in the front emission method, high transmittance, high adhesion, and low outgas generation are required.

Prior art Japanese Patent Laid-Open No. 2005-187636 discloses a photopolymerizable resin composition comprising a bisphenol type epoxy resin and a cationic photopolymerization initiator, but when used alone, the transmittance at wavelength 400 nm to 900 nm is 90% or less. As a result, the opening ratio is lowered.

Korean Patent Publication No. 10-2004-0106431 discloses a photopolymerizable resin composition comprising an acrylate resin and a radical photopolymerization initiator in order to solve such a problem of permeability. However, when the acrylic alone is used, the adhesive strength with the upper and lower plates is significantly reduced. There is a problem in that a large amount of gas is generated to shorten the life of the device.

As described above, in order to apply the transparent adhesive to the entire surface in the front emission method, low moisture permeability, high permeability, and high adhesive force are required.

An object of the present invention is to provide a curable resin composition capable of minimizing outgas and lowering the moisture permeability to increase device life of an organic light emitting display device and an organic light emitting display device including the same.

Curable resin composition according to the present invention is characterized in that it comprises an alicyclic epoxy, bisphenol-based epoxy resin, cationic photopolymerization initiator, a photosensitizer (Formula 1).

In addition, the curable resin composition of the present invention may be formed to have a viscosity of 10 mPa · s to 1,000 mPa · s at 25 ° C., shear rate = 1. When the curable resin composition becomes too low in viscosity, it becomes difficult to form a transparent layer having an appropriate thickness. That is, when the curable resin composition is used as the transparent adhesive layer in the organic electroluminescent display device, if the viscosity is too low, it is difficult to apply a layer of a suitable thickness. In addition, when the viscosity is too high, the curable resin composition becomes difficult to apply in a layer having a constant thickness.

Curable resin composition according to the present invention has the effect of reducing the outgas after curing by including a photosensitizer.

In addition, according to the present invention, the moisture permeability is low, so that the device life of the organic light emitting display device can be increased.

In addition, the curable resin composition according to the present invention has an effect that can be used as a transparent sealing agent for coating the entire surface of the organic light emitting display device.

Hereinafter, the curable resin composition of this invention is demonstrated in detail.

Curable resin composition which concerns on this invention is formed including alicyclic epoxy resin, bisphenol-type epoxy resin, a cationic photoinitiator, and a photosensitizer (Formula 1).

(A) cycloaliphatic epoxy resin

The cycloaliphatic epoxy resin forms a main component in the curable resin composition, and serves to control viscosity and improve total light transmittance.

As the alicyclic epoxy resin, commercially available Celoxide 2021, Celoxide 3000, Celoxide 2081, Dow's UVR-6105, UVR-6170, UVR-6110, and UVR-6128 may be used.

The alicyclic epoxy resin may be included in 50 to 90 parts by weight based on 100 parts by weight of the curable resin composition. When the content of the alicyclic epoxy resin is 50 parts by weight or less, a problem of total light transmittance occurs. In addition, if the content of the alicyclic epoxy resin is 90 parts by weight or more, there is a problem of moisture permeability.

In addition, the alicyclic epoxy resin is used having a viscosity of 1 ~ 1,000 cps.

(B) Bisphenol Epoxy Resin

The bisphenol-based epoxy resin forms a main component in the curable resin composition, and serves to control viscosity and improve moisture permeability.

The bisphenol epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol AD epoxy resins, novolac epoxy resins, naphthalene type epoxy resins, trisphenol methane type epoxy resins, and glycidyl amine type epoxy resins. It includes at least one selected from the group consisting of.

The bisphenol-based epoxy resin is commercially available from Epinic 840, Epicron 840-S, Epicron 850, Epicron 850-S, Epicron 850-CRP, Epicron 830, Epicron 830-S, EPICRON 830-LVP, EPICRON 835, EPICRON N-660, EPICRON N-740, EPICRON HP-820, EPICRON HP-4032, EPICRON EXA-7015, EP-4080S, EP-A from Asahi Denka Corporation 4085S, EP-4080, EP-4000S, Nagase Chemtex's EX-212L, EX-214L, EX-216L, EX-321L, EX-850L, Kukdo Chemical YD-128, YDF-134, YDF-8170, etc. It is possible.

The bisphenol-based epoxy resin may be included in 10 to 50 parts by weight based on 100 parts by weight of the curable resin composition. When the content of the bisphenol-based epoxy resin is more than 50 parts by weight, there is a problem in the total light transmittance. In addition, when the content of the bisphenol-based epoxy resin is less than 10 parts by weight, there is a problem of moisture permeability. The bisphenol-based epoxy resin may be more preferably included in 20 to 50 parts by weight based on 100 parts by weight of the curable resin composition.

The bisphenol-based epoxy resin is used having a viscosity of 1000 ~ 50,000 cps.

(C) cationic photopolymerization initiator

The cationic photopolymerization initiator may include at least one selected from onium salts such as aromatic diazonium salts, aromatic halonium salts, and aromatic sulfonium salts.

The cationic photopolymerization initiators are commercially available adekaoptomer SP-150, adekaoptomer SP-170, adekaoptomer SP-151, adekaoptomer SP-171 (manufactured by Asahiden Kasa), Photoinitiator 2074 (manufactured by Rhodia Co., Ltd.) ), CPI-110A (San-Epro), etc. can be used.

The cationic photopolymerization initiator may be included in 0.1 to 5 parts by weight based on 100 parts by weight of the curable resin composition. In addition, the cationic photopolymerization initiator may be included preferably 0.3 to 2 parts by weight. When the content of the cationic photopolymerization initiator is less than 0.1 part by weight, a problem of degree of curing occurs, and when greater than 5 parts by weight, a yellowing problem occurs.

In addition, the cationic photopolymerization initiator preferably has a purity of 50% or more. When the purity of the cationic photopolymerization initiator is 50% or less, outgas may be generated to shorten the life of the device.

(D) photosensitizer (Formula 1)

The photosensitizer improves the crosslinking density of the cured product during UV curing in the curable resin composition, thereby reducing the moisture permeability and reducing the amount of the cationic photopolymerization initiator, which is a problem of the outgas due to increased reactivity.

The photosensitizer includes a photosensitizer having a structure represented by Chemical Formula 1.

[Formula 1]

Where R is propoxy or butoxy.

The photosensitizer may be commercially available photosensitizers such as UVS-1331 (Kyokyo Chemical Industry), UVS-1221 (Kyokyo Chemical Industry), SP-100 (Adeca), and the like.

The photosensitizer may be included in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the curable resin composition. When the content of the photosensitizer is used in an amount of 0.01 parts by weight or less, the photosensitizer effect cannot be seen, and when used in an amount of 1 parts by weight or more, there is a problem of increasing moisture permeability.

1 is a schematic cross-sectional view of a top-emitting organic light emitting display device having a curable resin composition according to the present invention.

As shown in FIG. 1, the top emission type organic light emitting display device 100 includes a lower glass 110 in which the organic light emitting diode 111, the passivation layer 112, and the transparent adhesive layer 113 are sequentially formed. The upper glass 120 with the moisture absorbing layer 121 formed therein, and the encapsulant 130 encapsulating the lower glass 110 and the upper glass 120 are formed. The transparent adhesive layer 113 is formed to cover the passivation layer 112. In this case, the curable resin composition is dropped on the entire surface of the storage electroluminescent display including the passivation layer 112 to be completely coated and cured to form the transparent adhesive layer 113. In addition, the curable resin composition is formed of a layer having a constant thickness by a spin coating method, a blade coating method, or the like. Therefore, the transparent adhesive layer 113 serves to isolate the organic electroluminescent device 111 from external moisture and oxygen. In addition, the transparent adhesive layer 113 is to adhere the upper glass 120 to the top. The curable resin composition according to the present invention may be used for the transparent adhesive layer 113, thereby reducing the amount of outgas generated and lowering the moisture permeability to increase the lifespan of the organic light emitting display device.

The present invention will be described in more detail by the following examples and comparative examples, the following examples are only some specific examples of the present invention and are not intended to limit or limit the protection scope of the present invention.

<Example 1>

70 parts by weight of CEL-2021P manufactured by Daicel Corp. as the alicyclic epoxy resin, 30 parts by weight of YDF-8170 manufactured by Kukdo Chemical as the bisphenol-based epoxy resin, 1 part by weight of CPI-110A (acid-epro) as a cationic photopolymerization initiator, and 0.2 weight part of UVS-1331 (Tenkyo Chemical Co., Ltd.) was mix | blended with the sensitizer, and the curable resin composition was obtained.

<Example 2>

Curable resin composition was obtained like Example 1 except having used 30 weight part of YD-134 by Kukdo Chemical Co., Ltd. as said bisphenol-type epoxy resin.

<Example 3>

A curable resin composition was obtained in the same manner as in Example 1 except that 1 part by weight of adekaoptomer SP-170 was used as the cationic photopolymerization initiator.

<Example 4>

A curable resin composition was obtained in the same manner as in Example 1 except that 0.2 part by weight of adekaoptomer SP-100 was used as the photosensitizer.

<Example 5>

A curable resin composition was obtained in the same manner as in Example 1 except that 0.5 parts by weight of CPI-110A (acid-pro) was used as the cationic photopolymerization initiator.

<Example 6>

Curable resin composition was obtained like Example 1 except having used 0.5 weight part of cross-linkable UV-1331 as said photosensitizer.

Comparative Example 1

70 parts by weight of Daicel's CEL-2021P with the alicyclic epoxy resin, 30 parts by weight of YDF-8170 from Kukdo Chemical with bisphenol-based epoxy resin, and 1 part by weight of CPI-110A (acid-pro) with a cationic photopolymerization initiator are curable. The resin composition was obtained.

Comparative Example 2

A curable resin composition was obtained in the same manner as in Comparative Example 1 except that 100 parts by weight of bisphenol epoxy YDF-8170 alone was used as the epoxy.

Comparative Example 3

A curable resin composition was obtained in the same manner as in Comparative Example 1 except that 1 part by weight of adekaoptomer SP-170 was used as the cationic photopolymerization initiator.

<Comparative Example 4>

Curable resin composition was obtained like Example 1 except having used 100 weight part of alicyclic epoxy CEL-2021P alone as said epoxy.

Comparative Example 5

A curable resin composition was obtained in the same manner as in Comparative Example 1 except that 1.5 parts by weight of cross-linkable UV-1331 was used as the photosensitizer.

Experimental Example

1. Viscosity Measurement

After preparing curable resin composition, 0.25g is aliquoted and the viscosity in 25 degreeC and shear rate 1 is measured using rheometer MCR300 (Antonpa Co., Ltd.).

2. Moisture permeability measurement

The curable resin composition was cured in an oven at 80 ° C. for 1 hour after 6J / cm 2 irradiation to obtain a cured specimen having a thickness of 100 μm. The cured specimens were measured at 37.8 ° C. and 100% RH with a moisture permeability meter PERMATRAN-W 3/33 (manufactured by MOCON).

3. Permeability Measurement

The curable resin composition was cured in an oven at 80 ° C. for 1 hour after 6J / cm 2 irradiation to obtain a cured specimen having a thickness of 100 μm. The cured specimen was measured with a spectrophotometer CARY 100 UV-Visible Spectrophotometer (manufactured by Verian) to measure the transmittance of the cured specimen at a wavelength of 400 to 900 nm. The minimum transmittance at 400 ~ 900nm should be more than 90%.

4. Adhesion strength measurement

Curable resin composition was apply | coated to the center part of the wash | cleaned glass substrate, ITO glass substrate of the same size was attached to the board | substrate, and it UV-cured (6J / cm <2>), and it hardened in 80 degreeC and oven for 1 hour. After mounting the support apparatus on the obtained glass surface, the test piece for adhesive strength measurement was produced. The prepared specimens were measured for adhesive strength using UTM equipment (manufactured by Instron Co., Ltd.).

5. Out gas measurement

After the curable resin composition was applied to the cleaned glass substrate, it was placed in a test tube, sealed, UV cured (6J / cm 2), heat cured at 80 ° C. for 1 hour, and the outgas was collected by Pyrrolyze GC-MS.

6. Hardness Measurement

The curable resin composition was applied to a release film adhered on a glass substrate at 100 μm, and then UV cured (6J / cm 2), followed by thermosetting at 80 ° C. for 1 hour, and then fractionating the resulting cured film on the release film to THF solvent. 0.2 g was added to the solution for 2 hours, and a predetermined amount of the solution was measured by GPC (Agilent).

The result of evaluating curable resin composition of the said Example and the comparative example by the above-mentioned evaluation method is as following Table 1.

<Table 1>

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Epoxy resin CEL-2021P 70 70 70 70 70 70 70 70 100 70 YD-134 30 YDF-8170 30 30 30 30 30 30 100 30 30 Photopolymerization Initiator SP-170 One One CPI-110A One One One 0.5 One One One One One Photosensitizer UVS-1331 0.2 0.2 0.2 0.2 0.5 0.2 1.5 SP-100 0.2 Curing condition UV Curing (6J / cm ² ) + Heat Curing (80 ℃ 1hr) Measurement result Viscosity (mPas) 360 990 360 360 350 360 360 1000 350 250 355 Total light transmittance (400 ~ 900nm) 100 ㎛ > 98% > 98% > 98% > 98% > 99% > 99% > 99% > 92% > 99% > 99% > 97% Water vapor permeability (g / ㎡ · 4hr) 16 15 13 17 14 14 20 25 18 20 21 Adhesive strength (kg / ㎠) 15 13 15 16 15 16 14 5 13 11 12 Outgas (%) 0.2 0.14 0.2 0.3 0.01 or less 0.01 or less 0.5 1.2 0.3 0.15 0.3 Curing degree > 98% > 98% > 98% > 98% 97% 98% 95% 82% > 98% 88% 94%

As can be seen from Table 1, the curable resin composition according to the present invention exhibits a relatively low water vapor transmission rate while exhibiting a high total light transmittance. In addition, the curable resin composition according to the present invention has a relatively small outgas generation amount, and has a high degree of curing.

On the other hand, Comparative Examples 1 and 2, which do not contain a photosensitizer, are relatively high in moisture permeability. In addition, Comparative Example 2 does not contain an alicyclic epoxy resin has a low adhesive strength and a low degree of curing, and a large outgas content. In Comparative Example 3, the adhesive strength is relatively low. In addition, Comparative Example 3 is relatively low in the moisture permeability, adhesive strength and degree of curing.

1 is a cross-sectional view of a top-emitting organic light emitting display device having a curable resin composition according to the present invention.

<Description of Symbols for Main Parts of Drawings>

100; Organic electroluminescent display

110; Bottom glass 111; Organic light emitting device

112; Passivation layer 113; Transparent adhesive layer

120; Top glass 121; Hygroscopic layer

130; Encapsulant

Claims (10)

Curable resin composition comprising an alicyclic epoxy resin, a bisphenol-based epoxy resin, a cationic photopolymerization initiator and a photosensitizer (Formula 1): [Formula 1]

Formula 1 represents the photosensitizer, wherein R is propoxy or butoxy. The method of claim 1, The bisphenol epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol AD epoxy resins, novolac epoxy resins, naphthalene type epoxy resins, trisphenol methane type epoxy resins, and glycidyl amine type epoxy resins. Curable resin composition comprising at least one selected from the group consisting of. The method of claim 1, The cycloaliphatic epoxy resin is curable resin composition, characterized in that contained in 50 to 90 parts by weight relative to 100 parts by weight of the total curable resin composition. The method of claim 1, The bisphenol-based epoxy resin is 10 to 50 parts by weight based on 100 parts by weight of the total curable resin composition curable resin composition for an active organic electroluminescent display device. The method of claim 1, The cationic photopolymerization initiator is contained in 0.1 to 5 parts by weight based on 100 parts by weight of the total curable resin composition. The method according to claim 1 or 5, Purity of the said cationic photoinitiator becomes 50% or more, Curable resin composition characterized by the above-mentioned. The method of claim 1, Said photosensitizer is contained in 0.01-1 weight part with respect to 100 weight part of all said curable resin compositions, The curable resin composition characterized by the above-mentioned. The method of claim 1, Curable resin composition whose viscosity of the said curable resin composition is 10 mPa * s-1,000 mPa * s at 25 degreeC and shear rate = 1. The method of claim 8, The curable resin composition is added dropwise to the entire surface of the storage electroluminescent display device, the entire surface is applied and cured. A bottom plate glass in which an organic electroluminescent element, a passivation layer, and a transparent adhesive layer are sequentially formed; Upper glass with a moisture absorption layer formed; It includes an encapsulant formed on the edge of the lower glass and the upper glass, The organic adhesive display device of claim 1, wherein the transparent adhesive layer is formed of the curable resin composition according to any one of claims 1 to 8.