Encapsulation composition (as amended)

Abstract

An encapsulation composition, an encapsulation film including the same, an encapsulation product for organic electronic devices, and a method of manufacturing an organic electronic device are provided. The encapsulation composition can be useful in effectively preventing moisture or oxygen from flowing into the organic electronic device from external environments while realizing transparency when the organic electronic device is encapsulated by the encapsulation composition. Also, the encapsulation film formed of the encapsulation composition can be useful in ensuring mechanical properties such as handling properties and processability, and the organic electronic device whose encapsulation structure is formed by means of the encapsulation film may have improved lifespan and durability, thereby providing an encapsulation product for organic electronic devices showing high reliability.

Claims

1. An encapsulation composition comprising: a first resin having a weight average molecular weight of 100,000 to 2,000,000; a second resin, which is a polymer of a mixture comprising an alkyl (meth)acrylate and a monomer having at least one reactive functional group; and at least one multifunctional cross-linking agent selected from the group consisting of an isocyanate cross-linking agent, an epoxy cross-linking agent, an aziridine cross-linking agent, and a metal chelate cross-linking agent, wherein the first resin comprises a polyisobutylene resin, wherein the second resin has a cross-linked structure and forms a semi-interpenetrating polymer network with the first resin, wherein, in the second resin, the monomer having at least one reactive functional group is included in an amount of 5 to 50 parts by weight with respect to 100 parts by weight of the alkyl (meth)acrylate, and wherein the monomer having the reactive functional group comprises a hydroxyl group-containing monomer or a carboxyl group-containing monomer.

2. The encapsulation composition of claim 1, wherein the first resin has a contact angle of 80? or more with deionized water.

3. The encapsulation composition of claim 1, wherein the first resin has a glass transition temperature of 0? C. or less.

4. The encapsulation composition of claim 1, wherein the second resin is included at a content of 1 to 50 parts by weight, with respect to 100 parts by weight of the first resin.

5. The encapsulation composition of claim 1, wherein a difference in solubility parameter between the first resin and the second resin is 1 (cal/cm.sup.3).sup.1/2 or less.

6. The encapsulation composition of claim 1, wherein the alkyl (meth)acrylate satisfies the following Formula 1: ##STR00002## wherein R.sub.1 represents hydrogen, or an alkyl group having 1 to 4 carbon atoms, and R.sub.2 represents a linear, branched or cyclic alkyl group having 3 to 30 carbon atoms.

7. The encapsulation composition of claim 1, which has a light transmittance of 80% or more with respect to a visible ray region having a wavelength of 380 nm to 780 nm, as measured by a spectrophotometer when prepared in the form of a film.

8. The encapsulation composition of claim 1, further comprising a moisture absorbent.

9. An encapsulation film comprising an encapsulation layer formed from the encapsulation composition of claim 1.

10. An encapsulation product for organic electronic devices comprising: a substrate; an organic electronic device formed on the substrate; and the encapsulation film of claim 9 configured to encapsulate the organic electronic device.

11. A method of manufacturing an organic electronic device, comprising: applying the encapsulation layer of the encapsulation film of claim 9 to a substrate having an organic electronic device formed on a surface thereof to cover the organic electronic device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1 and 2 are cross-sectional views showing encapsulation films according to one exemplary embodiment of the present application; and

(2) FIG. 3 is a cross-sectional an encapsulation product for organic electronic devices according to one exemplary embodiment of the present application.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

(3) Hereinafter, the present invention will be described in further detail with reference to Examples according to the present invention and Comparative Examples not according to the present invention, but it should be understood that the Examples and Comparative Examples described below are not intended to limit the scope of the present invention.

Preparative Example 1: Polymerization of Second Resin (Alkyl(Meth)Acrylate Copolymer)

(4) A monomer mixture including 95 parts by weight of cyclohexyl methacrylate and 5 parts by weight of 2-hydroxyethyl acrylate was put into a 4-L reactor equipped with a cooling system to facilitate the reflux of nitrogen gas and the control of temperature, and 100 parts by weight of ethyl acetate was added as a solvent to the reactor. Thereafter, the reactor was purged with nitrogen gas for 60 minutes to remove oxygen, and kept at a temperature of 60? C. The resulting mixture was homogenated, and 0.04 parts by weight of azobisisobutyronitrile was added as a reaction initiator, reacted for 7 hours, and then diluted with ethyl acetate to obtain a polymer. Then, a copolymer having a weight average molecular weight of 850,000 and a molecular weight distribution of 2.31 was obtained by means of the polymerization reaction.

Example 1

(5) A polyisobutylene resin (Mw=500,000) and the acrylic copolymer prepared in Preparative Example 1 were mixed at a ratio of 90:10 as the first and second resins, respectively. Thereafter, a hydrogenated DCPD-based tackifier resin was mixed at a content of 20 parts by weight, with respect to the total weight of the first and second resins. 0.1 parts by weight (with respect to the total weight of the resin) of a tolylene diisocyanate addut (TDI) of isocyanate-based trimethylolpropane as a multifunctional cross-linking agent was added thereto, and the resulting mixture was diluted to a solid content of 20%, and homogeneously mixed. Subsequently, a release paper was coated with the mixture, and dried for 10 minutes in a 110? C. oven so that the coating had a thickness of 50 ?m after drying.

Example 2

(6) An encapsulation composition was prepared in the same manner as in Example 1, except that the ratio of that the first resin and the second resin used in Example 1 was changed to 80:20.

Example 3

(7) An encapsulation composition was prepared in the same manner as in Example 1, except that the ratio of that the first resin and the second resin used in Example 1 was changed to 70:30.

Example 4

(8) An encapsulation composition was prepared in the same manner as in Example 1, except that isobornyl acrylate was used instead of the cyclohexyl methacrylate in preparation of the second resin (the reaction temperature and method were the same for the second resin, and the encapsulation composition having a weight average molecular weight of 700,000 and a molecular weight distribution of 2.1).

Example 5

(9) An encapsulation composition was prepared in the same manner as in Example 1, except that methyl methacrylate was used instead of the cyclohexyl methacrylate in preparation of the second resin in Example (the reaction temperature and method were the same for the second resin, and the encapsulation composition having a weight average molecular weight of 840,000 and a molecular weight distribution of 3.9).

Example 6

(10) An encapsulation composition was prepared in the same manner as in Example 1, except that the ratio of that the first resin and the second resin used in Example 1 was changed to 30:70.

Comparative Example 1

(11) An encapsulation composition was prepared in the same manner as in Example 1, except that 100 parts by weight of the first resin was added without addition of the second resin used in Example 1, and a tackifier resin (a hydrogenated DCPD-based resin) was mixed at a content of 20 parts by weight, with respect to the total weight of the first resin.

Comparative Example 2

(12) An encapsulation composition was prepared in the same manner as in Example 1, except that a cyclohexyl methacrylate homopolymer was used instead of the second resin used in Example 1 without addition of the cross-linking agent (the reaction temperature and method were the same for the second resin, and the encapsulation composition having a weight average molecular weight of 800,000 and a molecular weight distribution of 2.5).

Experimental Example 1: Evaluation of Transmittance

(13) The encapsulation compositions prepared in Examples 1 to 6 and Comparative Examples 1 and 2 were prepared into encapsulation films so that the encapsulation layers had a thickness of approximately 50 ?m. The encapsulation layers of the prepared encapsulation films were transferred to a glass without formation of bubbles. Thereafter, the glass serving as the standard substrate was measured for light transmittance at a wavelength range of 380 nm to 780 nm using a UV/Vis spectrophotometer.

Experimental Example 2: Evaluation of Moisture Barrier Properties

(14) The encapsulation compositions prepared in Examples 1 to 6 and Comparative Examples 1 and 2 were prepared into encapsulation films so that the encapsulation layers had a thickness of approximately 100 ?m. Thereafter, the encapsulation layers were laminated with porous films, and base films were peeled to prepare test samples. Then, the test samples were measured for WVTR in a transverse direction in a state in which the test samples were positioned at 100? F. and 100% relative humidity. The WVTR was measured according to the ASTM F1249 standard.

Experimental Example 3: Evaluation of Cuttability

(15) The encapsulation compositions prepared in Examples 1 to 6 and Comparative Examples 1 and 2 were prepared into encapsulation films so that the encapsulation layers had a thickness of approximately 50 ?m and had a structure in which the bases films were present both surfaces of each of the encapsulation layers. The prepared encapsulation films were cut at a size of 100 mm?100 mm to prepare test samples. When relatively thin base films are peeled at a high speed to evaluate cuttability (?: excellent; ?: mean, and x: poor) of the encapsulation films, the cuttability is evaluated to be excellent when the encapsulation film is stably attached to a base film, mean when the encapsulation film is stably attached to a base film but delamination occurs at an end portion of the encapsulation film, and poor when the encapsulation film is generally delaminated from the thin base film due to exudation of the composition.

(16) TABLE-US-00001 TABLE 1 Moisture barrier properties, WVTR, Transmittance Item (g/m.sup.2 day) (%) Cuttability Example 1 3.2 94 ? Example 2 4.5 91 ? Example 3 7.8 91 ? Example 4 5.6 93 ? Example 5 10.7 80 ? Example 6 20.8 85 ? Comparative 3.0 94 X Example 1 Comparative 45.9 90 ? Example 2

(17) In the case of Comparative Example 1 in which the polyisobutylene resin was introduced as the first resin without a separate cross-linked structure, it could be seen that the encapsulation composition has excellent moisture barrier properties, but exhibited very poor cuttability. In the case of Comparative Example 2 in which no separate cross-linked structure was formed in the second resin, it could also be seen that the encapsulation composition exhibited poor cuttability and had has very poor moisture barrier properties.

DESCRIPTION OF REFERENCE NUMERALS

(18) 11: base film or release film 12: encapsulation layer 13: cover film 21: substrate 22: cover substrate 23: organic electronic device