SU990791A1 - Composition for treating phosphors based on zinc sulfide - Google Patents

Description

The aim of the invention is to improve the flowability of the zinc sulfide-based phosphor.

This goal is achieved by the fact that the composition for processing zinc sulfide-based phosphors includes components, wt.%: Tetraethyl ether

orthosilicic acid0, 50-2.00

Water 0.30-1.20

Orthophosphorus

acid 0.02-0.50

Monatomic limit alcohol 96,30-99,10

In addition, the composition contains as a ethyl derivative of orthosilicic acid its tetraethyl ester and additionally monohydric terminal alcohol and orthophosphoric acid.

The proposed composition readily wets the surface of sulfide phosphors particles, facilitating the formation of a uniform adsorption film on their surface, which prevents the particles from sticking together and ensures high flowability of the treated material.

The introduction of orthosiliconate into the composition of tetraethyl ester in a quantity less than 0.50 wt.% Results in insufficient hiding power of the particles of the treated phosphor by an adsorption film, which sharply reduces its flowability, bringing it closer to the flowability of the starting material the phosphor is 2.05).

The introduction of tetraethyl ester of orthosilicon in an amount greater than 2.0 wt.%, Also leads to a deterioration in the flowability of the treated phosphor.

The introduction of a less than stoichiometric amount of distilled water of 0.30 wt.% Does not ensure the complete hydrolysis of orthosilicic acid tetraethyl ester, and, consequently, obtaining a homogeneous composition suitable for the treatment of lumino (Foro.

An excess of water of 7.20% by weight leads to coagulation of silicic acid and the composition also becomes unsuitable for operation.

The introduction of orthophosphoric acid in an amount of less than -0.20 wt.% Sharply slows down the hydrolysis reaction of orthosilicic acid tetraethyl ester (the hydrolysis time increases to several months), therefore the proposed composition cannot be practically used. An increase in the orthophosphoric acid content of more than 0.50 wt.% Leads to a decrease in the flowability of the treated phosphor to the flowability value of the starting material.

The content of monatomic alcohol limit less than 96.30 wt.% Or more than 99.10 wt.% Leads to a change in the content of other components of the proposed composition beyond the specified limits and to the deterioration of the flowability of the treated phosphor.

In tab. 1 shows all the proposed and known compositions.

To prepare these formulations, orthosilicic acid tetraethyl ester, distilled water, and phosphoric acid are introduced into a glass flask. The mixture is shaken for 20-25 minutes until a uniform, clear solution is obtained. Ethyl alcohol is then poured in and shaken until the components are completely mixed.

The resulting compounds were treated with sulfide phosphors: ZnSAg, ZnS-CdS-Ag, ZnS-Cu and ZnS-CdS-Cu.

The processing of the phosphors on the example of the first composition lead in this way.

In a dry porcelain chagaque, 200 g of sulfide phosphor is weighed / the resulting solution of composition 1 is introduced into it and the mixture is stirred for 30 minutes. Then the phosphor is squeezed out on a Bphner funnel, transferred to a dry porcelain dish and dried at 120-15 ° C.

The resulting phosphor sample has a flowability (in relative units) of 1.73,

In tab. 2 shows the results of determining the flowability of the treated phosphor.

The data table. 2 show that. The proposed formulations 1,2,3,4,5 ob-, (C: they bake to obtain high flow, the value of the value of the tangent of the angle for them lies within 1.11-1.73, which is significantly less than the corresponding value for the untreated phosphor, Standard 2.0.05 Compositions 5.7.8 and a concentration of components which are outside the specified limits do not allow for high flowability of the treated phosphor, the relative value of which is 1.90-2.00.

The technical and economic effect of using the invention is determined by increasing the flowability of the treated phosphor, and, consequently, improving its application to the screen regardless of the method of application. In addition, the quality of the formed fine-structured screens is improved due to a more uniform and dense packaging of the phosphor grains.

Table I

0.50 1.00 2.00 0.30 0.60 1.20

0.10 0.02 0.02

Monoatomic limit alcohol (ethyl | Vyy) 99.10 98.38 1.73

1.11 1.23

Claims (2)

1. Gugel B.M. Phosphors for the electrovacuum industry, M., Energy, 1967 ,, p. 74.75. 2. Authors certificate of the USSR 357823, cl. From 09 to 1/04, 1971.