RU2651174C1 - Zeolite-based composite getter material and method of its production - Google Patents

Abstract

FIELD: package and storage.

SUBSTANCE: invention relates to getter materials for light-emitting devices. Composite getter material is designed to remove water vapor and residual oxygen. According to the invention, the surface of type A4 zeolite is coated with a liquid potassium-sodium alloy with a potassium content of 40 to 90 % by weight, with a weight fraction of the alloy with respect to zeolite of 0.5–10.0 %. Activation of zeolite is carried out by heating in a vacuum at a temperature of 250–300 °C for 4–6 hours. Zeolite is cooled in a dry argon atmosphere or in a vacuum down to 20–25 °C. Impregnation of zeolite pellets with alloy is carried out at 100–110 °C in a dry argon atmosphere.

EFFECT: invention provides an increase in the oxygen absorbing capacity of the material.

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Description

The invention relates to the electronics industry, to the manufacture of organic light emitting diodes (OLED-organic light emitting diodes).

In the manufacture of organic light emitting devices (OLED), it is necessary to protect the active layers from interaction with atmospheric oxygen and water vapor. To do this, when sealing (encapsulating) the finished device, getter materials are placed inside the housing.

Alkaline-earth oxide getter materials (CaO, BaO) are known (Jae-Hyung Park, Seong-Geun Oh, Preparation of CaO as OLED getter material through control of crystal growth of CaCO ₃ by block copolymers in water solution, Materials Research Bulletin, v. 44 (1), 2009, p. 110-118). These materials absorb residual water, which provides an increase in the service life of the device. To make getters, finely dispersed powders of alkaline earth metal carbonates or hydroxides are calcined, and then they are cooled in an atmosphere that does not contain water vapor (purified nitrogen or argon). A disadvantage of the known analogues is the lack of capacity for water vapor, in addition, they do not allow to bind traces of oxygen, which is why the encapsulation operation must be carried out in an inert gas atmosphere with a low oxygen content (0.1-0.5 ppm).

The closest analogue of the present invention is a zeolite-based getter, which is a paste containing, in addition to finely divided to 10 μm zeolite, water and an inorganic binder (M. Erdmann, N. Schall, A. Kirtikar, P-63: Getter Paste for OLED Application , SID Symposium Digest of Technical Papers, v. 37, (1), 2012, p 436-439). The advantage of this material is a higher capacity in relation to water vapor compared to traditional getters. The main disadvantages of the prototype are that its use requires an additional operation of zeolite activation, which consists in heating the entire device to 250 ° C, and, in addition, the problem of absorbing traces of oxygen by this material is not solved.

The technical problem to which the present invention is directed is the creation of a getter material that does not require activation and, moreover, is capable of absorbing traces of oxygen at room temperature.

The proposed material is granules of activated zeolite type 4A (average pore size 0.4 nm) with a diameter of 0.2-0.5 mm (Acros Organics, Belgium) coated with a potassium-sodium alloy (40 to 90 wt.% Potassium ), liquid at room temperature. It is preferable to use a eutectic alloy (78 wt.% Potassium). The mass fraction of the alloy with respect to the zeolite is 0.5-10.0%. At lower values of the alloy fraction, the capacity decreases; at higher values, the alloy is unevenly distributed on zeolite granules.

For zeolite, water is absorbed by adsorption in pores. When zeolite is impregnated with a potassium-sodium alloy, a mechanism of chemical bonding of oxygen appears.

The getter preparation process consists of the following stages: activation of the zeolite by heating in vacuum at a temperature of 250-300 ° C and a pressure of 10 ^-1 -10 ^-2 Torr for 4-6 hours, cooling in a dry argon atmosphere or vacuum to 20-25 ° C, adding to the zeolite a weighed amount of the alloy, impregnating the granules at 100-110 ° C in an atmosphere of dry argon for 2-4 hours with periodic stirring and cooling the product to room temperature in an atmosphere of protective gas (dry argon).

Thus obtained material is a granular granule of dark gray color, which can be stored for a long time (several months) in hermetically sealed containers in an inert atmosphere. The material does not require additional activation and when placed in the device’s case is ready for use.

Example 1

In a 1 L round-bottom flask equipped with a thermometer and a tap with a tap connected to the vacuum system, 95 g of granulated zeolite 4A is heated to 250 ° C for 5 hours at a pressure of 0.1 Torr, then cooled in vacuum to 25 ° C and fill the flask with dry argon. In a stream of argon add 5 g of the alloy containing 78 wt. % potassium and 22 wt. % sodium, close the flask and heat the mixture to 100 ° C for 2 hours, periodically shaking the flask until the entire alloy is absorbed and a uniformly gray powder is formed. The flask is then cooled and a getter containing 5% metal is stored in an inert atmosphere. The vapor content of water and oxygen in the gas above such a preparation was 0.5 and 0.8 ppm, respectively. Water vapor and oxygen vapor measurements were carried out using sensors MO-SE-1 and OX-SE-1 (M. Braun Inertgas-Systeme GmbH, Germany), directly connected to the measuring chamber.

Example 2

Similarly, 90 g of zeolite are applied 10 g of the alloy (10%) containing 90 wt. % potassium. The alloy is completely absorbed by zeolite in 2 hours at 110 ° C and periodically shaking. The vapor content of water and oxygen in the gas above such a preparation was 1.1 and 0.6 ppm, respectively.

Example 3

Similarly, on 99.5 g of zeolite, 0.5 (0.5%) g of an alloy containing 90 wt. % potassium. The alloy is completely absorbed by zeolite in 2 hours at 110 ° C and periodically shaking, forming a uniform dark gray coating on the granules. The vapor content of water and oxygen in the gas above such a preparation was 1.3 and 0.8 ppm, respectively.

Example 4

Similarly, 85 g of zeolite cause 15 g of the alloy (15%) containing 78 wt. % potassium. The alloy is not completely absorbed by zeolite, a sintered mass is formed, unsuitable for further use.

Example 5

Similarly, per 100 g of zeolite is applied 0.2 (0.2%) g of an alloy containing 90 wt. % potassium. The alloy is completely absorbed by zeolite in 2 hours at 110 ° C and periodically shaking, however, a uniform coating is not formed. Part of the granules remains uncovered by the alloy, so the material is unsuitable for use.

Claims (3)

1. A composite getter material based on zeolite, characterized in that the granules of activated zeolite type 4A with a diameter of 0.2-0.5 mm with an average pore size of 0.4 nm are coated with a liquid potassium sodium alloy with a potassium content of 40 to 90 wt. %, with a mass fraction of the alloy with respect to the zeolite of 0.5-10.0%. 2. A composite getter material according to claim 1, characterized in that a eutectic alloy with a potassium content of 78 wt. % 3. The method of obtaining the material described in paragraph 1, which consists in the activation of type 4A zeolite by heating in vacuum at a temperature of 250-300 ° C and a pressure of 10 ^-1 -10 ^-2 Torr for 4-6 hours, followed by cooling in the atmosphere dry argon or vacuum to 20-25 ° C, adding a weighed amount of alloy to the zeolite, impregnating the granules at 100-110 ° C in an atmosphere of dry argon for 2-4 hours with periodic stirring and cooling the product to room temperature in a dry argon atmosphere.