KR940009312B1 - Reprocessing method of color braun tube flourescent material - Google Patents

Abstract

The method re-uses the fluorescent material by easily removing added chemicals and an alien substance, employing a latex as a color material adhesive. The method includes a fluorescent material recovering process for recovering the fluorescent material in the fluorescent film process; an alkali thermal washing process for putting the recovered fluorescent material into a double tank, pouring pure water and alkali, heat-mixing, preserving and draining; an oxygen process for adjusting a pH value; a washing process; a dehydration process; and a drying process.

Description

Phosphor reprocessing method of color CRT

1 is a flowchart for explaining a phosphor reprocessing method of a color CRT according to the prior art.

2 is a flowchart for explaining a phosphor reprocessing method of a color CRT according to the present invention.

The present invention relates to a method for reprocessing a phosphor of a color CRT, and in particular, using a pigmented phosphor using a latex such as carboxylated acrylate as a pigment adhesive, to facilitate the reuse of the phosphor by easily removing the additives and foreign substances. A method for reprocessing a phosphor of one color CRT.

In the conventional color CRT fluorescent film forming method, a slurry obtained by combining phosphor powder with pure polyvinyl alcohol and other additives is applied to an inner surface of a panel, exposed to ultraviolet rays through a shadow mask, and developed with warm pure water.

At this time, the phosphor of the unexposed part to be removed is recovered by removing the moisture by a centrifuge.

Since the recovered phosphor is about 80% of the phosphor used in the form of a fluorescent film, the loss of materials is large, and since the phosphor contains a large amount of heavy metals, pollution problems are generated. Various types of phosphor reprocessing methods for reprocessing are known.

In the method of reprocessing the phosphor of a color CRT tube, which is mainly used, the recovered phosphor is put in a double stainless tank equipped with a heating device, injected with pure water, heated until boiling, and repeated about two hours of stirring for about one hour. After the drying and sieving to reuse the phosphor, another method is to put the recovered phosphor with a pigment in a double tank equipped with a heating device, injecting pure water, and then adding alkali such as caustic soda, After heating and stirring, pure water is washed several times, and then the pigment is reattached, dried and sieved to reuse the phosphor.

In the boiling water or thermal alkali cleaning process, polyvinyl alcohol, a photosensitive agent, and other additives added during the phosphor slurry combination are dissolved and removed to be reused.

1 is a flowchart illustrating a phosphor reprocessing method of a color CRT according to the prior art.

However, the fluorescent material reprocessing method of the color CRT as described above does not completely remove the additives or impurities during the boiling water washing, so when used with several times of processing, the characteristics of the phosphor change and cannot be used normally. In case of alkaline heat washing, the washing is relatively good, but when gelatin and gum arabic are used as the pigment adhesive, the gelatin and gum arabic and the pigment are removed together during the washing so that the pigment must be reattached. There was a difficulty.

Therefore, not only separate materials and facilities are required for the pigment attachment, but also there is a problem that the overall productivity is lowered.

The present invention was devised to solve the above-mentioned problems, and reprocessed by using a pigmented phosphor that uses a latex such as carboxylated acrylate as a pigment adhesive, and does not need to reattach the pigment separately. To reduce the material and facilities, and to enable the re-processing within a short time to improve the overall productivity, the present invention will be described below with reference to the accompanying drawings.

The fluorescent material reprocessing method of the color CRT tube according to the present invention, as shown in FIG. 2, is a phosphor recovery step for recovering the phosphor in the fluorescent film step of the CRT, and the recovered phosphor is placed in a double tank equipped with a heating device. After pouring pure water and caustic soda which is an alkaline component, heating and stirring, and then stirring and draining, an alkaline heat washing process, a pure water is injected, followed by a washing, heating, stirring, standing, and draining process, and pure water is injected. After heating, the pH is adjusted with nitric acid or hydrochloric acid, followed by an acid treatment step of standing and draining, a washing step of washing 2-3 times with warm pure water, and dehydration, drying, sieving and packaging.

As the phosphor in the fluorescent film process of the CRT, a pigmented phosphor using a latex such as carboxylated acrylate as a pigment adhesive is used.

Alkali used in the alkaline heat washing step is 3 ⁵ ~ 17 ⁵ % by weight relative to the phosphor, and the temperature is adjusted to 45 ~ 90 ℃ in the alkaline heat wash step.

In addition, the acid treatment step is preferably repeated two or more times.

EXAMPLE

The pigment-attached phosphor using latex as a pigment adhesive is used for the process of forming a fluorescent film of a color CRT, and 70 kg of the phosphor collected by a centrifuge is dispersed in pure water, and then transferred to a double tank equipped with a heating device, followed by 300 l of pure water. (Liter) is injected and heated to 80 ° C.

Thereafter, 20 L of 25% caustic soda solution was injected, followed by stirring for 3 hours, and after standing for 1 hour, draining.

Again, 300 L of pure water is poured, heated to 80 ° C, stirred for 1 hour, left for 1 hour, then drained and repeated once.

Again, 300 liters of pure water was injected, the temperature was raised to 80 ° C., the pH was adjusted to 2 ² with nitric acid, and stirred for 1 hour, and after standing for 1 hour, draining.

Again, pure water injection, elevated temperature, pH adjustment, stirring, standing and draining are repeated twice.

Again, 300 L of pure water was injected, and then heated to 70 ° C, stirred for 1 hour, left for 1 hour, drained, and repeated twice.

Thereafter, dehydration with a perforated centrifuge, followed by drying in an electric drying furnace at 150 ° C. for 12 hours, and sieving to complete reprocessing.

As a result of coating, exposing and shaping the phosphor slurry by combining the phosphor slurry by the phosphor reprocessing method of the color CRT tube as described above, it was found that a phosphor film having the same level as that of the new phosphor was obtained.

In the phosphor reprocessing method of the color CRT as described above, polyvinyl alcohol, added chemicals and foreign substances are removed by the corrosive action of the heated alkali, and the alkali which is not removed in the acid treatment step is removed.

In addition, if too much alkali is used or the temperature is too high during the process, the latex is removed, the pigment is peeled off, too little alkali is used, or if the temperature is too low, the cleaning is insufficient, so be careful. In particular, when the photoresist used in the phosphor slurry combination, that is, the removal of the dichromic acid is insufficient, the adhesive force is changed when the phosphor is applied, so it is difficult to develop, which requires attention.

As described above, the phosphor reprocessing method of the color CRT according to the present invention does not need to reattach the pigment separately because the pigment is not peeled off, and thus, there is an advantage of reducing the rework material and facilities, and also a short time. Since the reprocessing process can be performed inside, there is an effect that the overall productivity is improved.

In addition, since the substance is effectively removed and there is almost no change in properties, the application, recovery and reprocessing can be continued several times, and the effect of improving the coating film quality by improving the dispersion of the phosphor particles in the repeated washing process is improved. have.

Claims (5)

Phosphor recovery step of recovering the phosphor in the fluorescent film process of the CRT, alkaline heat washing to put the recovered phosphor in a double tank equipped with a heating device, injecting pure water and alkali, stirring and heating, and then left still and drained Process, washing with water, injecting pure water, heating, adjusting the pH with nitric acid or hydrochloric acid, and then performing acid treatment for standing and draining, washing with water, dewatering, preforming and sieving. The phosphor reprocessing method of the color CRT. The phosphor reprocessing method of a color CRT tube according to claim 1, wherein the phosphor in the CRT process of the CRT is a pigment-attached phosphor using latex as a pigment adhesive. According to claim 1, wherein the alkali used in the alkaline heat washing process is 3 ⁵ ~ 17 ⁵ % by weight relative to the phosphor, the phosphor of the color CRT tube characterized in that the temperature is adjusted to 45 ~ 90 ℃ in the alkaline heat washing process. Rework method. The method for reprocessing a phosphor of a color CRT according to claim 1 or 3, wherein the alkali used in the alkaline heat washing step is caustic soda. The method for reprocessing a phosphor of a color CRT according to claim 1, wherein the acid treatment step adjusts the pH to 2-5.