JPH0675368B2 - Display tube manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a display tube, and more particularly to a method for forming an intermediate film on a fluorescent surface.

[Outline of Invention]

The present invention prints an intermediate film by using a paste whose viscosity is adjusted by adding an ammonium salt of an acrylic acid resin to a base emulsion as a paste for forming an intermediate film on the fluorescent surface of a display tube. It can be formed.

[Conventional technology]

The fluorescent surface of the cathode ray tube is generally composed of red, blue, and green color phosphor layers formed on the inner surface of the panel, an intermediate film formed on the color phosphor layers, and a metal backing of Al. In the production of a cathode ray tube, when forming this intermediate film, a solution having an intermediate film composition is injected into the inner surface of the panel on which the phosphor layer is formed, rotated and shaken off, and then heated by a heater. It's a film.

[Problems to be solved by the invention]

As described above, in the case of a normal cathode ray tube, since the inner surface of the panel is curved, the interlayer film is formed by using the interlayer film solution having a low viscosity. On the other hand, when the fluorescent surface is flat like a cathode ray tube for projectors and a flat fluorescent display tube, it is not possible to form an intermediate film using a conventional low-viscosity intermediate film solution. Can not. Further, since the fluorescent surface is a flat surface, it is advantageous in the process to form this intermediate film by printing as well as the color fluorescent material layer. In addition, it has been proposed to use a copolymer of allyl alcohol and methyl methacrylate as a base emulsion to obtain a screen-printable paste (Japanese Patent Application No. 58-
246657), but the desired viscosity was difficult to obtain.

The present invention provides a method for manufacturing a display tube capable of forming an intermediate film by printing.

[Means for solving problems]

In the method of manufacturing a display tube according to the present invention, a paste having a viscosity adjusted by adding an ammonium salt of an acrylic acid resin to a base emulsion is used as a paste for printing and forming an intermediate film on a fluorescent surface.

The viscosity of the paste to be adjusted is set, for example, in the range of 5000 to 50000 cps so that the paste has a viscosity suitable for printing.

As the resin in the base emulsion, for example, an acrylic ester resin can be used. The chemical structural formulas of acrylic acid resin, ammonium salt of acrylic acid resin and acrylic acid ester resin are as follows.

[Operation] Acrylic acid resin is insoluble in water, but when ammonia water is added to emulsion of this acrylic acid resin, ammonium salt of acrylic acid resin is produced as shown in the following reaction formula. Since this ammonium salt is water-soluble, it dissolves in water to increase the viscosity of the solution and imparts an appropriate viscosity as a printing paste.

Example First, 600 g of Bind Serum WA-400 (manufactured by Mitsui Toatsu Chemicals, Inc., trade name of acrylic acid ester resin) was put in a container, and then stirred with a stirrer (440 rpm) ammonia water (14.5 rpm). %), And then a mixture of 108 g of 2- (2-butoxyethoxy) ethanol (commonly known as carbitol) and 0.9 ml of ammonia water is added dropwise at a rate of 2-3 drops per second. When the dropping is completed, stop stirring,
After temperature adjustment, filtration is performed to obtain a mixed solution of acrylic acid ester resin, carbitol, and ammonia water. The viscosity of this mixed solution was 15 to 20 cps.

Next, while taking the above mixed solution in a 500 ml container, while stirring (440 rpm) 52 g of bind serum thickener WA-400 (trade name of acrylic resin) manufactured by Mitsui Toatsu Chemicals, Inc. Insert and gradually increase the rotation speed. The dropping is completed before curing. As a result, the acrylic acid resin reacts with the aqueous ammonia in the mixed liquid to generate an ammonium salt of acrylic acid. After the addition of the bind-serum thickener is completed, the rotation speed is increased to 1200 rpm and the mixture is agitated, and it is cured in about 5 minutes. Decrease the rotation speed and continue stirring for about 60 minutes, and if the surface becomes hard, break the solid. In order to prevent re-curing, an appropriate amount of the above mixed solution was added, the mixture was sealed with aluminum foil, and allowed to stand until the next day to obtain an intermediate film printing paste. The viscosity of this paste is 9,000 ~
It was 10000 cps. That is, this paste had a viscosity suitable for screen-printing an intermediate film.

〔The invention's effect〕

According to the present invention, since an ammonium salt of an acrylic acid resin is added to a base emulsion having a low viscosity, a paste having a high viscosity can be obtained and an intermediate film can be formed by printing. Moreover, by selecting an acrylic ester resin as the resin for the base emulsion, the viscosity is further increased due to the structural similarity. Since printing can be performed similarly to the case of the color phosphor layer, improvement in productivity can be expected.

Claims (1)

[Claims] 1. A method for producing a display tube, wherein an intermediate film on a fluorescent surface is formed by printing using a paste whose viscosity is adjusted by adding an ammonium salt of an acrylic acid resin to a base emulsion.