JPS6012382B2 - Method for regenerating pigmented phosphors - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a pigment-attached phosphor used for forming a high-contrast color cathode ray tube, etc., and a pigment-attached phosphor used for forming a light film. This invention relates to a method for regenerating pigmented poppies and light bodies.

The light surface of a color cathode ray tube is formed by the following process. In other words, a phosphor slurry (a phosphor dispersed in an aqueous solution of a water-soluble photoresist such as polyvinyl alcohol and ammonium dichromate) is uniformly coated on the inner surface of the panel glass using a spin coating method or the like. Apply and dry.

Next, ultraviolet rays are irradiated and exposed through a shadow mask. Finally, this is developed with water to remove the unexposed areas and the light material. Here, the process of removing polyvinyl alcohol and ammonium dichromate from the poppy/light material (slurry) recovered during spin coating or development is called regeneration.

The following methods are generally used to regenerate poppies and photobodies.

[1' Baking method] For example, the baking method shown in Tokubatsu No. 5957/1986, which removes the organic matter (polyvinyl alcohol) of the photoresist component and the pigment-adhered poppy, In the case of phosphors, the pigment and the organic binder of the phosphor are almost completely removed.

However, this method causes a decrease in brightness due to baking of the phosphor, discoloration due to a small amount of baking residue, and reattachment of the pigment and phosphor (
The problem is that a pigment re-deposition process is essential.

[21 Method using hot water treatment] For example, there is a method of treating the recovered slurry with hot water as shown in Samurai Kanka 51-124 Group No. 3, and this method removes polypinyl alcohol, which is a component of the photoresist.

However, with this method, it is difficult to remove agglomerates of poppies and photoparticles caused by the oil reaction of the photoresist or by light irradiation.

'3' Treatment method using an oxidizing agent For example, a method of treating the recovered slurry using an oxidizing agent as shown in Tokukan Sho 51-131486,
This method removes polypinyl alcohol, which is a component of the photoresist.

When using a poppy flower, a poppy flower with a pigment attached as a light body, or a light body, it depends on what is used as a binder for the pigment, a poppy flower, and a light body. Regarding the pigment-attached phosphor obtained in No. 56146), ``Not all of the above regeneration methods can be applied.

For example, in (1), the pigment and the light body separate, and a step of redepositing the pigment is required. The method of regenerating the attached poppy and light body must be selected according to the type of pigment and the binder of the poppy and light body.

The present invention involves binding pigments using acrylic resin as a binder,
It concerns a method for regenerating a pigment-attached phosphor attached to a photoresist, and ``compared to conventional methods, it does not require a step of redepositing the pigment (therefore it is economically advantageous), and it also eliminates the need to remove the photoresist. The aim is to provide a complete method.

Known methods for producing pigmented poppies and light bodies include:
S. There is a method by Mr. A. Rip (Japanese Unexamined Patent Publication No. 50-56146).

This is made by adsorbing poppy seeds, gelatin on the phosphor, and polyvinylpyrrolidone on the pigment in an aqueous solution.Then, the two are brought into contact to adhere the pigment to the surface of the phosphor, and after drying, a finishing ring is applied to the product. (hereinafter abbreviated as G/P method). In addition, the method we developed for producing pigment-attached poppies and light bodies (method using emulsion as a binder, hereinafter abbreviated as E method) includes the following. A cationic acrylic resin is attached to a poppy, an anionic acrylic resin is attached to a light body, and then the pigment is removed by contacting the two,
After adhering to the surface of the light body, the post-process is washing, dehydration,
After going through the drying and finishing process, the pigmented poppies and luminous bodies are obtained.

Samurai Isoaki No. 51-151988 Add L pigment and anionic acrylic emulsion to the poppy/light body aqueous suspension, and further '1) Make the system neutral or weakly acidic, or make a thionic acrylic emulsion. By adding or performing steps [1} and '2' together, the pigment is removed and the light body is attached, and the pigment is deposited through a post process to obtain the light body.

Tokukai No. 52-40395 poppy, pigment and anionic acrylic emulsion were added to the aqueous suspension of the light substance, and magnesium t-calcium,
Among the water-soluble salts of barium, zinc and aluminum,
By adding at least one kind of pigment, the pigment is melted and the light body is attached, and then the pigment is attached and the light body is obtained through a post-process.

A method for regenerating pigmented poppies and light bodies was investigated using the above-mentioned GnoP method and E method for pigmented poppies and light bodies.

First, I tried baking.

Baking at 450-550 pm caused the pigment and phosphor to peel off in both the GnoP and E methods, requiring the above-described deposition step to be repeated.

Since the process of attaching pigments requires many days and labor, such a regeneration method is not very economical, so we considered regeneration treatment using hot water or various oxidizing agent aqueous solutions.

Prior to this experiment, we first investigated to what extent the cured film of polyvinyl alcohol and ammonium dichromate photoresist (hardened by time reaction and photoreaction) could be removed by overflowing water or various oxidizing agent aqueous solutions. The results are summarized in a table. As is clear from the table, it was found that the cured product of the water-soluble photoresist was hardly removed by water or hot water.

When the pigment-adhered lamp and light body were treated with the above oxidizing agent aqueous solution by the G/P method and the E method, the pigment peeled off at the processing stage under both treatment conditions in the case of the G/P method. On the other hand, no peeling of the pigment was observed when using method E.

Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 Red poppy, luminous material (Y202S:Eu) 600 yen, water 60
Then, 60 g of a 3% aqueous solution of red pigment (red pigment), which had been ball-milled in advance, was added.
After stirring for 30 minutes, an anionic acrylic emulsion with a solid content of 33.3% (a copolymer of ethyl acrylate, methyl methacrylate, and acrylic acid, each in a ratio of 7.
After heating for another 30 minutes, a cationic acrylic emulsion (a copolymer of ethyl acrylate, methyl methacrylate, and dimethylaminoethyl methacrylate) with a solid content of 49% each was added. .5/49.5/1) Add 24 evenings,
The pH of the system was adjusted to 5.0 with dilute hydrochloric acid.

Next, the material was washed with water, dehydrated, dried, and finished to obtain a single luminous poppy with red pigment attached. Red pigmented poppy, light body 600 saw, 10% PVA (polyvinyl alcohol) aqueous solution 440
evening, 5% ammonium dichromate aqueous solution 70 evenings, 5% Pluronic-92 solution 12 evenings, 10% Tween 2 K solution 3 evenings, 20% Tamol 731 aqueous solution 15 evenings, and water 8 evenings.
60 minutes was added to form a red pigment-adhered slurry and a luminous slurry. This slurry was uniformly applied to a glass panel (green and blue poppies, on which a light pattern had already been formed) using a centrifugal coating method, and exposed and developed to form a light surface.

After washing the poppy seeds and photoluminescent slurry collected during development,
It was treated with 5% hydrogen peroxide solution at 65°C for 30 minutes, washed with water, and then treated with Su's hydrochloric acid for 30 minutes, followed by washing, drying, and finishing. There was almost no peeling of the pigment in this recycled poppy material, and even when it was used again as a slurry, there were no problems such as a decrease in the coatability of the luminescent film or a decrease in brightness. It was also possible to repeat the playback. In addition, instead of 5% hydrogen peroxide solution, 2% and 10% hydrogen peroxide solution or 0.2% hydrogen peroxide solution,
0. S.I. Similar effects were obtained with a 0% sodium hypochlorite aqueous solution.

In addition, treatment with Su's hydrochloric acid removes small amounts of green and blue phosphors (ZnS) that are mixed into the red pigment-attached phosphor.
This was done to remove the .

In addition, S. When similar experiments were carried out on a red pigment-adhered lamp and a light body made by Mr. IJ Tsupp's method (G/P method), most of the pigment was removed during the treatment with 5% hydrogen peroxide, and the light body It has peeled off even more.

Example 2 An experiment similar to Example 1 was conducted on a blue pigmented phosphor.

A blue pigmented poppy and a light body were obtained by the following steps.

That is, 300 grams of blue poppy and light material (ZnS:Ag) were suspended in 300 grams of water to create an emulsion whose main component was a copolymer of ethyl acrylate and acrylic acid (97/3) with a solid content of 10%. After carefully adding 20 minutes of water suspension and 40 minutes of 10% blue pigment (cobalt aluminate) water suspension, 4 hours of 5% zinc acetate was added while continuing to stir, and then the pH of dilute hydrochloric acid was adjusted to 4 hours. It was set as .5. Next, it was washed, dehydrated, dried, and finished to coat it with blue pigment, creating a luminous body. Blue pigmented poppy, luminous material 300 saw, 10%P
VA aqueous solution 2 pieces, 5% ammonium dichromate solution 27
In the evening, 3 volumes of 5% Pluronic L-92 solution, 3 volumes of 10% Tween 20 solution and 400 volumes of water were added to prepare a blue pigment-adhered phosphor slurry.

This slurry was uniformly applied to a glass panel (green poppy, on which a light pattern had already been formed) using a centrifugal coating method, and exposed and developed to form a light surface.

After washing the poppy seeds and photoluminescent slurry collected during development,
It was treated with 0.5% sodium hypochlorite at room temperature for 2 hours, washed with water, dried and finished, and then regenerated.

There was no peeling of the pigment during these steps, and when this recycled product was used again as a slurry, it improved the coating properties and brightness.
The brightness was also the same as new.

Note that repeated reproduction was also possible. Also, instead of sodium hypochlorite, hydrogen peroxide (10%, 25q0, 60 minutes), sodium bromite (5%, 60°C, 30 minutes), sodium periodate (5%, 60°C) Similar results were obtained using 30 minutes).

In addition, S. When similar experiments were conducted on a blue pigment-attached phosphor made by Mr. A. Lip's method (G/P method), most of the pigment was removed during treatment with a 0.5% sodium hypochlorite aqueous solution. It has peeled off.

Claims (1)

[Claims] 1. The pigment-attached phosphor with acrylic resin as a binder recovered in the phosphor film forming process is treated with hydrogen peroxide,
1. A method for regenerating a pigment-attached phosphor, comprising treating it in an oxidizing agent aqueous solution containing at least one of sodium hypochlorite, sodium periodate, and sodium bromite.