RADIATION CURABLE COMPOSITION COMPRISING HYDROPHILIC NANOPARTICLES

Abstract

The present invention relates to a radiation curable composition. In particular, the present invention relates to a radiation curable composition with hydrophilic nanoparticles for use in barrier stacks for protection of sensitive devices against moisture.

Claims

1. A radiation curable composition for use in barrier stacks for protection of sensitive devices against moisture, comprising a curable material and hydrophilic nanoparticles, wherein the proportion of hydrophilic nanoparticles is in the range of 0.01 wt % to 0.9 wt % of the weight of the curable material.

2. A radiation curable composition according to claim 1, wherein the proportion of hydrophilic nanoparticles is in the range of 0.05 wt % to 0.2 wt % of the weight of curable material, preferably 0.05 wt % to 0.1 wt % of the weight of curable material.

3. The radiation curable composition according to claim 1, comprising: at least one monomer at least one radiation active initiator.

4. The radiation curable composition according to claim 3, wherein the monomer is mono-functional and/or multi-functional.

5. The radiation curable composition according to claim 1, comprising: hydrophilic nanoparticles in a ratio of 0.01 wt % to 0.9 wt %, preferably 0.05 wt % to 0.5 wt %, more preferably 0.05 wt % to 0.2 wt % and most preferably 0.05 wt % to 0.1 wt % with regard to the weight of the polymerizable material; at least one photo initiator, preferably a radical photoinitiator; component A: at least one acrylate or methacrylate component with a c log P higher than 2, preferably higher than 4, more preferably higher than 5; component B: at least one monofunctional acrylate or methacrylate diluent component, preferably with a viscosity below 40 mPa.Math.s at 20° C.; component C: at least one acrylate or methacrylate component with functionality equal or higher than 3, preferably 3 or 4.

6. The radiation curable composition according to claim 5, further comprising a component D, which is at least one of a polybutadiene acrylate or methacrylate, a silicone acrylate or methacrylate, or a two-mole ethoxylated bisphenol A di(meth)acrylate, or any mixture thereof, whereby such component D exhibits preferably two (meth)acrylate functionalities.

7. The radiation curable composition according to claim 5, comprising hydrophilic nanoparticles in a ratio of 0.01 wt % to 0.9 wt %, preferably 0.05 wt % to 0.5 wt %, more preferably 0.05 wt % to 0.2 wt % and most preferably 0.05 wt % to 0.1 wt % with regard to the weight of the polymerizable material; 0.1-10 wt % of a photo initiator; 30-80 wt % of component A, which preferably exhibits two (meth)acrylate functionalities; 5-40 wt % of monofunctional (meth)acrylate diluent component B; 5-30 wt % of (meth)acrylate component C with functionality equal or higher than 3; and optionally 0.1-30 wt % of component D; based on the total weight of the composition.

8. The radiation curable composition according to claim 5, comprising hydrophilic nanoparticles in a ratio of 0.01 wt % to 0.9 wt %, preferably 0.05 wt % to 0.5 wt %, more preferably 0.05 wt % to 0.2 wt % and most preferably 0.05 wt % to 0.1 wt % with regard to the weight of the polymerizable material; 0.1-5 wt % of a photo initiator; 40-70 wt % of component A, which exhibits preferably two (meth)acrylate functionalities; 10-30 wt % of the monofunctional (meth)acrylate diluent component B; 7-20 wt % of the (meth)acrylate component C with functionality equal or higher than 3; and optionally 0.3-25 wt % of component D; based on the total weight of the composition.

9. The radiation curable composition according to claim 1, characterized in that more than 80 wt % of the composition are components with a boiling point higher than 180° C. at 760 mmHG, more preferred higher than 200° C. at 760 mmHG, and most preferred higher than 220° C. at 760 mmHG.

10. The radiation curable composition according to claim 1, characterized in that it contains no solvent.

11. The radiation curable composition according to claim 1, wherein the hydrophilic nanoparticles have an average particle diameter less than 200 nm.

12. The radiation curable composition according to claim 1, wherein the hydrophilic nanoparticles comprise zeolite.

13. The radiation curable composition according to claim 1, wherein the hydrophilic nanoparticles have a calculated logarithm of partition coefficient between n-octanol and water in the range of 0 to +0.5.

14. The radiation curable composition according to claim 12, wherein the hydrophilic nanoparticles are calcium oxide or barium oxide or magnesium oxide or mixtures thereof.

15. A method of manufacturing an organic layer (12, 24) using the radiation curable composition according to claim 1 comprising: bringing the composition in contact with a rigid or flexible substrate or an in-organic layer, optionally heating the composition and; polymerizing the composition with radiation, preferably actinic radiation.

16. An organic layer, which has been manufactured from a composition according to claim 1.

17. The organic layer according to claim 16, wherein the thickness of the layer is 1 μm to 100 μm.

18. Use of a radiation curable resin composition according to claim 1, to manufacture an organic layer (12, 24) as a part of barrier stack for protecting moisture sensitive opto-electronic elements or devices.

19. Use of a radiation curable resin composition according to claim 1, to manufacture an organic layer (12, 24) for encapsulating opto-electronic elements or devices in a multi dyad configuration, preferably in a single dyad configuration, more preferably in a double dyad configuration.

20. Use of an organic layer according to claim 16 in organic light emitting diodes, organic photovoltaics, organic field effect transistors, flexible electronics, flexible substrates, batteries, medical packaging, food packaging and liquid crystal displays.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0080] The invention is further illustrated by the accompanying drawing figures. It is emphasized that the various features are not necessarily drawn to scale.

[0081] FIG. 1 shows a top emitting opto-electronic device 10 with an encapsulation stack comprising a double dyad configuration with organic layers 12 comprising low concentration of hydrophilic nanoparticles as well as inorganic layers 11, substrate 14 and opto electronic element 13.

[0082] FIG. 2 shows a double dyad configuration in a bottom emitting opto-electronic device 20 with an encapsulation stack comprising two organic layers 24 with low concentration of hydrophilic nanoparticles, cover 21, substrate 25, opto electronic element 22 and inorganic layers 23.

[0083] FIG. 3 shows the occurrence of black spots in a bottom emitting opto-electronic device.

[0084] FIG. 4 shows the top view of three bottom emitting opto-electronic devices before reliability test.

[0085] FIG. 5 shows the top view of three bottom emitting opto-electronic devices after reliability test.

[0086] FIG. 6 shows a graph with fraction of black spot rejects during the reliability test time at 60° C. and 90% relative humidity. The comparison is between stacks made from compositions without (0.00%) and with 0.1 wt % hydrophilic nanoparticles used to prepare organic layers.

DETAILED DESCRIPTION OF THE INVENTION

[0087] Even though the compositions according to the present invention comprise a very low amount of hydrophilic nanoparticles, superior water absorption properties are observed.

EXAMPLES

[0088] The commercially available components listed in table 1 are used to prepare the compositions used in the examples.

TABLE-US-00001 TABLE 1 Boiling Point Trade Name Supplier Chemical Name at 760 mmHG Structure SR595 Arkema 1,10-decanediol diacrylate ~371° C. [00001] SR351 Arkema Trimethylolpropane triacrylate   390° C. [00002] SR307 Arkema Poly(butadiene) diacrylate (Polymer) [00003] SR421A Arkema Isophoryl methacrylate ~258° C. [00004] Omnirad 248 IGM resins 2-Benzyl-2- (dimethylamino)-4′- morpholino- butyrophenone [00005] CaO Strem Calcium Oxide MgO Strem Magnesium Oxide BaO Strem Barium Oxide Lucidot NZL 40 Clariant Nanozeolite CN9010EU Sartomer Aliphatic urethane acrylate

[0089] The calculated logarithm of partition coefficient c Log P between n-octanol and water for CaO, MgO and Bao is +0.33.

Example 1

Preparation of Composition 1

[0090] A preliminary composition is prepared by mixing together SR595, SR351, SR307, SR421A and Omnirad248 according to the wt % in table 2 and stirring at 300 rpm at room temperature for 2 hours. The mixture is then dried over 4 Å molecular sieves (preliminary activated in a vacuum oven at 140° C. for 24 hours) during 24 hours, then filtered prior to the use for the preparation of the final composition.

[0091] Calcium oxide particles were dried in an oven as described in WO 2014/012931 and then mixed according to wt % in table 2 with the above preliminary composition in order to obtain dispersions. The dispersion is then milled using a DynoMill equipment for about two hours to obtain a dispersion of particles with an average size <200 nm and a final composition 1 is obtained.

Example 2

Preparation of Composition 2

[0092] Composition 2 is prepared in the same manner as in example 1, except that calcium oxide particles of 0.1% of the total weight of the composition are used as in table 2.

Example 3

Preparation of Composition 3

[0093] Composition 3 is prepared in the same manner as in example 1, except that calcium oxide particles of 0.05% of the total weight of the composition are used as in table 2.

TABLE-US-00002 TABLE 2 Composition 1 Composition 2 Composition 3 Components [wt %] [wt %] [wt %] SR307 17.060 17.080 17.090 SR595 48.370 48.420 48.440 SR351 9.480 9.490 9.490 CD421A 22.800 22.820 22.830 Omnirad 248 2.090 2.090 2.100 CaO 0.200 0.100 0.050 Total (weight %) 100.00 100.00 100.00 Each of the compositions 1-3 is solvent free.

Example 4

Preparation of Composition 4

[0094] Composition 4 is prepared in the same manner as in example 1, except that the components are mixed as in table 3 and barium oxide particles are used.

Example 5

Preparation of Composition 5

[0095] Composition 5 is prepared in the same manner as in example 4, except that barium oxide particles of 0.1% of the total weight of the composition are used as in table 3.

Example 6

Preparation of Composition 6

[0096] Composition 6 is prepared in the same manner as in example 4, except that barium oxide particles of 0.05% of the total weight of the composition are used as in table 3.

TABLE-US-00003 TABLE 3 Composition 4 Composition 5 Composition 6 Components [wt %] [wt %] [wt %] SR307 17.060 17.080 17.090 SR595 48.370 48.420 48.440 SR351 9.480 9.490 9.490 CD421A 22.800 22.820 22.830 Omnirad 248 2.090 2.090 2.100 BaO 0.200 0.100 0.050 Total (weight %) 100.00 100.00 100.00 Each of the compositions 4-6 is solvent free.

Example 7

Preparation of Composition 7

[0097] Composition 7 is prepared in the same manner as in example 1, except that the components are mixed as in table 4 and magnesium oxide particles are used.

Example 8

Preparation of Composition 8

[0098] Composition 8 is prepared in the same manner as in example 7, except that magnesium oxide particles of 0.1% of the total weight of the composition are used as in table 4.

Example 9

Preparation of Composition 9

[0099] Composition 9 is prepared in the same manner as in example 7, except that magnesium oxide particles of 0.05% of the total weight of the composition are used as in table 4.

TABLE-US-00004 TABLE 4 Composition 7 Composition 8 Composition 9 Components [wt %] [wt %] [wt %] SR307 17.060 17.080 17.090 SR595 48.370 48.420 48.440 SR351 9.480 9.490 9.490 CD421A 22.800 22.820 22.830 Omnirad 248 2.090 2.090 2.100 MgO 0.200 0.100 0.050 Total (weight %) 100.00 100.00 100.00 Each of the compositions 7-9 is solvent free.

Example 10

[0100] The average diameter of particle dispersion in compositions 1 to 9 is measured using dynamic light scattering equipment (DLS), a zetasizer Nano S from malvern instruments. Details about this method to measure particle diameter can be found in: “Nanomaterials: Processing and Characterization with Lasers”, Chapter 8, Size determination of Nanoparticles by Dynamic Light Scattering from S. C. Singh, H. Zeng, C. Guo and W. Cai; DOI: 10.1002/9783527646821.ch8.

[0101] The measurement results of the average particle diameter are listed in table 5. The average particle diameter is between 100 nm to 200 nm.

TABLE-US-00005 TABLE 5 Avg. particle Composition diameter (nm) Composition 1 172.4 Composition 2 172.4 Composition 3 172.4 Composition 4 <200 Composition 5 <200 Composition 6 <200 Composition 7 116 Composition 8 116 Composition 9 116

Example 11

[0102] Haze and water absorption is measured for the films prepared using compositions 1 to 9. The compositions are applied on glass substrate using a bar coater with a wire bar of 50 μm, then the homogenous film coating is cured with UV light (395 nm) with an exposure dose of 4 J/cm.sup.2 in an inert atmosphere resulting in a cured film with a thickness of 30 μm to 35 μm ready for measurements. The results are summarized in table 6.

Determination of Haze

[0103] Measurement is done according to the standard ASTM D1003 “Standard Test Method for Haze and Luminous Transmittance of Transparent Plastics”. Transmission Haze is the percent of transmitted light that is scattered more than 2.5° from the direction of the incident beam. Materials with haze values greater than 30% are considered diffusing.

Transmissive Haze is calculated as H=Tdiffuse/Ttotal×100%

[0104] Measurement of Transmissive Haze of films coated on a substrate has been performed with the Kontron Spectrophotometer UVIKON 810 (P12/301142). Compositions 1 to 9 have been coated on glass and cured with UV light under inert atmosphere using UV LED @ 395 nm with UV energy dose of 4 J/cm.sup.2 and measured for haze. The measurement error is +/−0.1%

Measurement of Water Absorption

[0105] The water absorption of cured samples of the compositions 1 to 9 was measured in order to determine the amount of water that each material is able to absorb. Samples of compositions 1 to 9 were placed in different aluminum cups (roughly 1.5 g of composition) and cured under inert atmosphere using UV LED @ 395 nm with 4 J/cm.sup.2 of UV dose. The cured solid part was then placed in 40° C./90% RH storage conditions. Due to water absorption, the weight of the sample increased over time. The sample weight was monitored over time until the weight became constant, which represents the saturation level from which the water absorption (weight %) was calculated. This is intrinsically a determination of the water gettering capacity of the dispersions.

TABLE-US-00006 TABLE 6 Avg. particle Haze (%) Haze (%) Water Composition diameter (nm) at 540 nm at 600 nm absorption (%) Composition 1 172.4 0.2 0 0.44 Composition 2 172.4 0 0 0.4 Composition 3 172.4 0.1 0.1 0.38 Composition 4 <200 0 0 0.41 Composition 5 <200 0.1 0.1 0.42 Composition 6 <200 0.2 0.2 0.35 Composition 7 116 0.2 0.2 0.33 Composition 8 116 0.2 0.1 0.33 Composition 9 116 0 0 0.29

Occurrence of Black Spots

[0106] When moisture permeates into the OLED device, black spots 30 appear as shown in FIG. 3, which affects the performance of the device for example by reduction of light intensity. A good OLED should have very low black spot rejects when subjected to reliability tests at 60° C./90% RH for a long duration.

Example 12

[0107] A bottom emitting type OLED device 20 with a double dyad configuration as in FIG. 2, is prepared, wherein the organic layers 24 in the double dyad configuration are made from composition 2.

[0108] Three top emitting type OLED devices 10 with double dyad configurations as in FIG. 1 were prepared, wherein the organic layers 12 in the double dyad configurations were made using composition 2. The OLED devices were then subjected to a reliability test for 2000 h at 60° C. and 90% relative humidity (RH) and were observed regarding degradation of the optical performance due to black spot occurrence.

[0109] FIG. 4 shows three OLED devices in emission mode before the reliability test.

[0110] FIG. 5 shows three OLED devices in emission mode after reliability test for 2000 h at 60° C./90% RH

[0111] As seen from FIG. 5, no black spots are observed in all of the devices after the reliability tests.

[0112] FIG. 6 shows a graph depicting fraction of black spot rejects for the above devices with organic layers 24 in a double dyad configuration containing 0.1% calcium oxide nanoparticles in comparison to a device wherein the organic layer has no hydrophilic nanoparticles. The device is subjected to reliability test at 60° C./90% RH for long duration.

[0113] As seen from FIG. 6, the radiation curable composition of the present invention with very low amount of nanoparticles shows superior performance when used in opto-electronic devices.

Example 13

Preparation of Composition 10

[0114] A preliminary composition is prepared by mixing together CN9010EU, SR595, SR351, Omnirad248 according to the wt % in table 7 and stirring at 300 rpm at room temperature for 2 hours. The mixture is then dried over 4 Å molecular sieves (preliminary activated in a vacuum oven at 140° C. for 24 hours) during 24 hours, then filtered prior to the use for the preparation of the final composition.

[0115] Zeolite particles (Lucidot NZL 40) were dried in an oven between 200° C.-400° C. and then mixed according to wt % in table 7 with the above preliminary composition in order to obtain dispersions. The dispersion is then milled using a DynoMill equipment for about two hours to obtain a dispersion of particles with an average size <200 nm and a final composition 10 is obtained.

TABLE-US-00007 TABLE 7 Composition 10 Composition 11 Composition 12 Components [wt %] [wt %] [wt %] CN9010EU 25.870 25.950 25.980 SR595 51.740 51.900 51.950 SR351 19.900 19.960 19.980 Omnirad 248 1.990 1.990 1.990 Lucidot NZL 0.500 0.200 0.100 40 Total 100.00 100.00 100.00 (weight %)

Example 14

Preparation of Composition 11

[0116] Composition 11 is prepared in the same manner as in example 13, except that zeolite particles of 0.2% of the total weight of the composition are used as in table 7.

Example 15

Preparation of Composition 12

[0117] Composition 12 is prepared in the same manner as in example 13, except that zeolite particles of 0.1% of the total weight of the composition are used as in table 7.