Adhesive composition

Abstract

Provided are an adhesive composition and an organic electronic device (OED) including the same, and particularly, an adhesive composition, which may form a structure effectively blocking moisture or oxygen flowing into an OED from the outside, realize a top-emission OED and exhibit excellent handleability and processability, and an OED including the same.

Claims

1. An adhesive composition for encapsulating an organic electronic element, comprising: a heat-curable resin which comprises a polyester resin, an isocyanate resin or an epoxy resin; a photocurable compound which comprises an acrylate compound; and an olefin-based resin having a water vapor transmission rate (WVTR) of 50 g/m.sup.2.Math.day or less, and satisfying General Equation 1, wherein the olefin-based resin, the heat-curable resin and the photocurable compound are included at 40 to 90 parts by weight, 5 to 50 parts by weight and 1 to 40 parts by weight, respectively:
F600 g.sub.f[General Equation 1] where F is a shear strength, the adhesive composition is applied in a circle on a lower glass having a size of 5 cm9 cm (widthlength), and an upper glass having a size of 5 cm9 cm (widthlength) is laminated on the adhesive composition to overlap the lower glass 5 cm in a widthwise direction and 2.5 cm in a lengthwise direction, thereby preparing a specimen in which the adhesive composition is disposed between the upper and lower glasses in a circle having a diameter of 17 mm and a thickness of 20 m, and the specimen is irradiated with light in the UV-A wavelength range at a dose of 3 J/cm.sup.2, the upper glass and lower glass were fixed to a texture analyzer (XT2 plus), and the upper glass was pulled in a lengthwise direction at 0.1 mm/sec at 25 C. to measure a force, and the maximum value of the measured force is defined as F.

2. The adhesive composition of claim 1, wherein the olefin-based resin has a weight average molecular weight of 100,000 or less.

3. The adhesive composition of claim 1, wherein the heat-curable resin comprises one or more heat-curable functional groups.

4. The adhesive composition of claim 3, wherein the heat-curable functional group comprises an epoxy group, a glycidyl group, an isocyanate group, a hydroxyl group, a carboxyl group or an amide group.

5. The adhesive composition of claim 1, wherein the heat-curable resin is comprised at 10 to 70 parts by weight with respect to 100 parts by weight of the olefin-based resin.

6. The adhesive composition of claim 1, further comprising: a heat-curing agent.

7. The adhesive composition of claim 6, wherein the heat-curing agent is a latent curing agent.

8. The adhesive composition of claim 1, wherein the photocurable compound comprises a multifunctional active energy ray-polymerizable compound.

9. The adhesive composition of claim 1, wherein the photocurable compound is comprised at 10 to 100 parts by weight with respect to 100 parts by weight of the olefin-based resin.

10. The adhesive composition of claim 1, further comprising: a photoradical initiator at 0.1 to 20 parts by weight with respect to 100 parts by weight of the photocurable compound.

11. The adhesive composition of claim 1, further comprising: a moisture absorbent.

12. The adhesive composition of claim 11, wherein the moisture absorbent is comprised at 5 to 100 parts by weight with respect to 100 parts by weight of the olefin-based resin.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a cross-sectional view of an OED according to an exemplary embodiment of the present application.

LIST OF REFERENCE NUMERALS

(2) 1: adhesive

(3) 10: side encapsulation layer

(4) 11: entire encapsulation layer

(5) 21: substrate

(6) 22: cover substrate

(7) 23: organic electronic element

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

(8) Hereinafter, the present application will be described in further detail with reference to examples according to the present application and comparative examples not according to the present application, and the scope of the present application is not limited to the following examples.

Example 1

(9) A polyisobutylene resin (BASF, B14, Mw=65,000) as an olefin-based resin, a hydrogenation BPA epoxy resin (DIC, Epiclon 850, Mw=376) as a heat-curable resin and an epoxy-modified acrylate (Sartomer, CN2003) as a photocurable compound were put into a mixing vessel in a weight ratio of 70:20:10 (B14:Epiclon850:CN2003) at room temperature. As a radical initiator, 1 part by weight of 2,2-dimethoxy-1,2-diphenylethane-1-one (Irgacure 651, Ciba) was put into the vessel with respect to 100 parts by weight of the photocurable compound, and as a heat-curing agent, 5 parts by weight of an imidazole-based curing agent (2P4MHZ) was put into vessel with respect to 100 parts by weight of the heat-curable resin. Meanwhile, as a moisture absorbent, 10 parts by weight of calcium oxide (CaO, Aldrich) was further put into the vessel with respect to 100 parts by weight of the olefin-based resin.

(10) A homogeneous composition solution was prepared in the mixing vessel using a planetary mixer (Kurabo Industries, KK-250s).

Example 2

(11) An adhesive composition was prepared by the same method as described in Example 1, except that an olefin-based rein, a heat-curable resin and a photocurable compound were put into a mixing vessel in a weight ratio of 50:20:30.

Example 3

(12) An adhesive composition was prepared by the same method as described in Example 1, except that an olefin-based rein, a heat-curable resin and a photocurable compound were put into a mixing vessel in a weight ratio of 60:20:20.

Example 4

(13) An adhesive composition was prepared by the same method as described in Example 1, except that an olefin-based rein, a heat-curable resin and a photocurable compound were put into a mixing vessel in a weight ratio of 30:20:50.

Example 5

(14) An adhesive composition was prepared by the same method as described in Example 1, except that an olefin-based rein, a heat-curable resin and a photocurable compound were put into a mixing vessel in a weight ratio of 40:50:10.

Comparative Example 1

(15) An adhesive composition was prepared by the same method as described in Example 1, except that an olefin-based rein and a heat-curable resin were put into a mixing vessel in a weight ratio of 80:20, and a photocurable compound was not added.

Comparative Example 2

(16) An adhesive composition was prepared by the same method as described in Example 1, except that, instead of the olefin-based resin of Example 1, an acrylic copolymer prepared by copolymerizing n-butyl acrylate and acrylic acid in a weight ratio of 95:5 was used, and the acrylic copolymer, a heat-curable resin and a photocurable compound were put into a mixing vessel in a weight ratio of 60:20:20.

(17) Hereinafter, physical properties in the examples and comparative examples were evaluated by the following methods.

(18) 1. Fluidity Control in Heat Curing

(19) The adhesive composition prepared in each of the examples and the comparative examples was applied for coating a 0.7 T soda lime glass and pressed with the same type of glass, thereby preparing a sample, and then irradiated with light in the UV-A wavelength range at a dose of 3 J/cm.sup.2 using a metal halide lamp. Subsequently, the outermost portion of the sample was marked with a pen, cured in an oven at 100 C. for 2 hours, and then observed to determine if an initial shape is maintained (in Comparative Example 1, heat curing is only performed in an oven at 100 C. for 3 hours). According to observation with the naked eye, when the outermost shape, right after the light irradiation, had been very excellently maintained, it was denoted as , when the outermost shape was larger than the boundary marked with a pen, but had almost maintained the initial shape, it was denoted as O, and when the outermost shape had not been maintained due to diffusion of the adhesive composition beyond the boundary marked with a pen, it was denoted as X.

(20) 2. Moisture Barrier Property

(21) To investigate a moisture barrier property of the adhesive composition of each of the examples and the comparative examples, a calcium test was performed. In detail, 7 spots of calcium (Ca) each having a size of 5 mm5 mm and a thickness of 100 nm were deposited on a glass substrate having a size of 100 mm100 mm, the adhesive composition of each of the examples and the comparative examples was applied at a peripheral portion (edge) at 3 mm intervals from the calcium deposited spot using a dispenser, a cover glass was laminated on each calcium deposited spot and pressed so that the adhesive composition had a width of 3 mm, and then the adhesive composition was irradiated with light in the UV-A wavelength range at a dose of 5 J/cm.sup.2. Afterward, the adhesive composition was cured in a high temperature dryer at 100 C. for 3 hours, (in Comparative Example 1, only heat curing was performed in an oven at 100 C. for 3 hours), and the encapsulated calcium (Ca) specimen was cut into pieces in a size of 14 mm14 mm. The obtained specimens were maintained in a constant temperature and humidity chamber in an environment of a temperature of 85 C. and 85% R.H. for 1000 hours, and the time when the calcium started becoming transparent by an oxidation reaction caused by moisture permeation was evaluated, which is shown in Table 1.

(22) 3. Measurement of Shear Strength

(23) In detail, the adhesive composition of each of the examples and the comparative examples was applied in a circle to a lower glass having a size of 5 cm9 cm (widthlength), an upper glass having a size of 5 cm9 cm (widthlength) was laminated on the adhesive composition to overlap the lower glass 5 cm in a widthwise direction and 2.5 cm in a lengthwise direction, thereby preparing a specimen in which the adhesive composition is overlapped with the two pieces of the glasses in a circle having a diameter of 17 mm and a thickness of 20 m. The specimen was irradiated with light in the UV-A wavelength range at a dose of 3 J/cm.sup.2, the upper glass and the lower glass were fixed to a texture analyzer (XT2 plus), and the upper glass was pulled in a lengthwise direction at 0.1 mm/sec at 25 C. to measure a force. The maximum value of the measured force was defined as shear strength F.

(24) TABLE-US-00001 TABLE 1 Shear Moisture barrier strength (F) property Fluidity control g.sub.f hrs in heat curing Example1 1645 700 Example2 6091 650 Example3 3458 670 Example4 850 400 Example5 780 350 Comparative 299 670 X Example1 Comparative 2458 12 X Example2