KR930010518B1

KR930010518B1 - Surface-treating of sulfurated calcium fluorescent

Info

Publication number: KR930010518B1
Application number: KR1019900014005A
Authority: KR
Inventors: 박영배
Original assignee: 삼성전관 주식회사; 김정배
Priority date: 1990-09-05
Filing date: 1990-09-05
Publication date: 1993-10-25
Also published as: KR920006473A

Abstract

The surface treating method of a calcium sulphide fluorescent material is characterized by (a) adding the fluorescent material (CaS:Eu) into an aq. potassium silicate soln., (b) regulating the mixt. with an acetic acid to pH 1.5-2.5, and then filtering and drying the fluorescent material, and (c) firing it at 500-900 deg.C for 1-3 hr. The content of a potassium silicate in the soln. is 0.1-10 wt.% w.r.t. 100 wt.% pure water. The surface-treated fluorescent material has an improved water resistance and a good luminescent property.

Description

Surface treatment method of calcium sulfide-based phosphor

제1도는 표면 미처리 CaS : Eu 형광체(A)와 표면 처리 CaS : Eu 형광체(B)의 시간에 따른 전기 전도도의 변화를 나타낸 그래프.1 is a graph showing the change in electrical conductivity over time of the surface-treated CaS: Eu phosphor (A) and the surface-treated CaS: Eu phosphor (B).

본 발명은 황화칼슘에 형광체의 표면처리방법에 관한 것으로서, 상세하게는 황화칼슘(CaS)계 형광체의 표면을 각종 유기물 또는 무기물로 표면처리하여 황화칼슘(CaS)계 형광체의 내수성을 향상시킨 황화칼슘계 형광체의 표면처리 방법에 관한 것이다.The present invention relates to a method for surface treatment of phosphors on calcium sulfide. Specifically, the surface of calcium sulfide (CaS) -based phosphors is surface treated with various organic or inorganic substances to improve the water resistance of calcium sulfide (CaS) -based phosphors. It relates to a surface treatment method of a system phosphor.

최근 들어 발광 특성이 우수한 형광체로 황화칼슘계 형광체가 주목되어 있다. 그런데 이러한 황화칼슘계 형광체는 그 특성상 물과 쉽게 반응하므로 형광체의 표면에 어떠한 처리를 하지 않고서는 사용이 불가능한 단점이 있다. 즉, 형광체 슬러리 제조시 황화칼슘계 형광체가 물과 반응하여 형광체 표면에 산화칼슘이 형성되면서 황이 수소와 결합하여 유독성 황화 수소기체를 발생시킨다.In recent years, calcium sulfide-based phosphors have attracted attention as phosphors having excellent luminescence properties. However, since the calcium sulfide-based phosphor easily reacts with water due to its characteristics, it cannot be used without any treatment on the surface of the phosphor. That is, during the manufacture of the phosphor slurry, the calcium sulfide-based phosphor reacts with water to form calcium oxide on the surface of the phosphor, whereby sulfur combines with hydrogen to generate toxic hydrogen sulfide gas.

따라서 이러한 형광체는 발광특성은 우수하나 내수성이 약하고 인체에 유해한 황화수소기체를 발생하므로 실용화되지 못하고 있다.Therefore, these phosphors have excellent luminescence properties but are not practical because they have weak water resistance and generate hydrogen sulfide gas harmful to the human body.

이를 극복하기 위한 방법으로 각종 유기물 또는 무기물 등을 사용하여 형광체 표면에 피복처리를 하거나 또는 다른 물질과의 혼용 소성처리를 하여 모체를 변경시키려는 방법등이 있다. 그러나 이들 방법에 의해서도 내수성은 크게 향상되지 못하는 문제가 있다.As a method for overcoming this problem, there is a method of changing the mother body by coating the surface of the phosphor using various organic materials or inorganic materials, or by mixing and baking with other materials. However, even by these methods, there is a problem that the water resistance is not greatly improved.

본 발명의 목적은 상기 문제를 감안하여 CaS계 형광체의 표면을 처리하여 CaS계 형광체에 내수성을 부여하고 슬러리 상태의 형광체를 사용하는 모든 공정에 적용 가능하게 하는 CaS계 형광체의 제조방법을 제공하는 것이다.Disclosure of Invention It is an object of the present invention to provide a method for producing a CaS-based phosphor which treats the surface of the CaS-based phosphor to provide water resistance to the CaS-based phosphor and makes it applicable to all processes using slurry-type phosphors. .

상기 목적을 달성하기 위하여 본 발명의 황화칼슘계 형광체의 표면처리방법은 황화칼슘계 형광체의 표면 처리 방법에 있어서, 규산 칼륨 용액에 황화칼슘계 형광체를 첨가하는 단계와, 상기 용액의 pH를 1.5 내지 2.5로 조정한 후 상기 형광체를 여과, 건조하는 단계와, 얻어진 상기 형광체를 산화성 분위기하에서 소성하여 분급하는 단계로 이루어지는 점에 그 특징이 있다.In order to achieve the above object, the surface treatment method of the calcium sulfide-based phosphor of the present invention comprises the steps of adding a calcium sulfide-based phosphor to the potassium silicate solution in the surface treatment method of the calcium sulfide-based phosphor, and the pH of the solution is 1.5 to It is characterized in that it comprises a step of filtering and drying the phosphor after adjusting to 2.5, and calcining and classifying the obtained phosphor in an oxidizing atmosphere.

본 발명에서 사용된 상기 규산 칼륨 용액의 양은 순수 100중량%에 대하여 0.1~10중량%이고, 초산을 가하여 pH가 1.5~2.5가 되도록 하고, 상기 소성단계중 소성온도는 500 내지 900℃이고 소성시간은 1 내지 3시간인 것이 바람직하다.The amount of the potassium silicate solution used in the present invention is 0.1 to 10% by weight with respect to 100% by weight of pure water, so that the pH is 1.5 to 2.5 by adding acetic acid, the firing temperature is 500 to 900 ℃ and firing time during the firing step Is preferably 1 to 3 hours.

본 발명의 황화칼슘계 형광체의 표면처리방법을 설명하면 다음과 같다.Referring to the surface treatment method of the calcium sulfide-based phosphor of the present invention.

0.1 내지 10중량%의 규산칼륨 용액을 순수에 첨가하여 혼합하고 여기에 황화칼슘계 형광체를 투입하여 충분히 교반한다. 이때 규산칼륨용액은 형광체 표면에 석출되고 소성공정을 통해 형광체 표면에 소망하는 규소칼륨염을 형성하고 그후 경화된다.0.1-10% by weight of potassium silicate solution is added to the pure water and mixed, and calcium sulfide-based phosphor is added thereto and sufficiently stirred. At this time, the potassium silicate solution precipitates on the surface of the phosphor, forms a desired potassium salt on the surface of the phosphor through a calcination process, and then hardens.

본 발명에서 사용된 황화칼슘계 형광체로는 CaS를 모체로 하는 적색발광 형광체이고 대표적으로 CaS : Eu 형광체를 들 수 있다.The calcium sulfide-based phosphor used in the present invention is a red light-emitting phosphor having CaS as a parent, and typically, a CaS: Eu phosphor.

본 발명의 바람직한 실시예를 설명하면 다음과 같다.Referring to the preferred embodiment of the present invention.

[실시예]EXAMPLE

규산칼륨용액 5g을 순수 100g에 첨가하여 혼합하고 여기에 CaS : Eu 형광체 50g을 투입하여 충분히 교반하였다. 얻어진 형광체 혼합물에 초산을 가하여 pH를 2.0로 조정한 후 여과하여 건조하였다. 그후 얻어진 형광체를 산화성 분위기하에서 800℃, 2시간동안 소성하고 시브하여 표면처리된 본 발명의 황화칼슘계 형광체를 얻었다.5 g of potassium silicate solution was added to 100 g of pure water, mixed, and 50 g of CaS: Eu phosphor was added thereto, followed by sufficiently stirring. Acetic acid was added to the obtained phosphor mixture to adjust the pH to 2.0, followed by filtration and drying. Subsequently, the obtained phosphor was calcined and sieveed at 800 ° C. for 2 hours in an oxidizing atmosphere to obtain a calcium sulfide-based phosphor of the present invention.

얻어진 본 발명의 황화칼슘계 형광체에 대하여 시간에 따른 전기전도도를 측정하였으며, 그 결과를 제1도에 나타내었다.The electrical conductivity of the calcium sulfide-based phosphor of the present invention was measured over time, and the results are shown in FIG.

제1도는 표면 미처리 CaS : Eu 형광체(A)와 표면처리 CaS : Eu 형광체(B)의 시간에 따른 전기전도도의 변화를 나타낸 그래프이다.1 is a graph showing the change of electrical conductivity with time of the surface-treated CaS: Eu phosphor (A) and the surface-treated CaS: Eu phosphor (B).

제1도로부터 알 수 있는 바와 같이, (A) 형광체는 순수에 투입됨과 동시에 전기전도도가 급격하게 상승함을 알 수 있었고, B형광체는 전기전도도의 시간에 따른 상승속도가 (A)형광체에 비해 매우 완만함을 알 수 있었다.As can be seen from FIG. 1, the phosphor (A) was introduced into pure water and the conductivity increased rapidly. As for the phosphor B, the rate of increase in the electrical conductivity over time was higher than that of the phosphor (A). It was very gentle.

이는 형광체의 표면처리에 의해 내수성이 크게 향상되었음을 의미하는 것이다.This means that the water resistance was greatly improved by the surface treatment of the phosphor.

이상에서 설명한 바와 같이, 본 발명에 의하여 황화칼슘계 형광체의 표면을 무기물로 처리한 형광체의 표면처리 방법에 의해 형광체의 내수성이 매우 향상되었고 그로 인한 발광특성이 우수한 황화칼슘계 형광체의 실용화를 달성할 수 있어 장차 공업적 이용가치가 큰 것으로 기대된다.As described above, according to the present invention, by the surface treatment method of the phosphor treated with the surface of the calcium sulfide-based phosphor with an inorganic substance, the water resistance of the phosphor was greatly improved, and thus the practical use of the calcium sulfide-based phosphor having excellent luminescent properties could be achieved. In the future, the industrial value of use is expected to be large.

Claims

In the surface treatment method of the calcium sulfide-based phosphor, adding a calcium sulfide-based phosphor to the potassium silicate solution, after adjusting the pH of the solution to 1.5 to 2.5, filtering and drying the phosphor, and the obtained phosphor A method of treating a surface of a calcium sulfide-based phosphor, characterized in that the step of firing and classifying in an oxidizing atmosphere.

The method of claim 1, wherein the amount of potassium silicate in the aqueous potassium silicate solution is 0.1 to 10% by weight based on 100% by weight of pure water.

The method of claim 1, wherein the firing temperature is 500 to 900 ° C., and the firing time is 1 to 3 hours.

The surface treatment method of the calcium sulfide-based phosphor according to any one of claims 1 to 3, wherein the calcium sulfide-based phosphor is a CaS: Eu phosphor.