JP3091797B2 - Filming agent for cathode ray tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a cathode ray tube, for example, a color picture tube, in which a phosphor film is formed on an inner surface of a panel and then a resin film used as a base for forming a metal reflection film is formed. A filming agent used for

[0002]

2. Description of the Related Art Generally, when a phosphor layer of a color picture tube is formed, a phosphor layer composed of phosphors of three colors of green, blue and red is formed on the inner surface of the panel, and then aluminum is vapor-deposited. A reflection film is formed, and a filming step is performed before depositing aluminum to make the metal reflection film flat and high in reflectivity. In this filming step, a filming agent is applied on the unevenness of the phosphor layer surface,
This is a step of forming a resin film layer and making it flat. The film layer is thermally decomposed and removed in a baking step after forming the aluminum vapor deposition film. Conventionally, a material comprising a polyacrylate emulsion has been used as the filming agent for a cathode ray tube. (For example, JP-B-47-24416)

[0003]

In order to increase the reflectance of an aluminum vapor-deposited film to improve the brightness of a phosphor screen,
The film to be formed must be flat, but in order to obtain sufficient flatness, the film needs to be at least about 7 microns thick. However, conventional filming agents containing polyacrylate emulsion as a main component have a high thermal decomposition temperature and insufficient thermal decomposability. However, a phenomenon of so-called unburnt residue that remains after being partially incinerated occurs, and a disadvantage occurs in that the luminance of the phosphor screen is reduced. For this reason, the film thickness of the film is limited to at most about 4 microns, and the flatness of the film is insufficient.

[0004]

In order to improve the brightness of the phosphor screen, the inventors of the present invention have developed a heat treatment that does not cause unburned film in the baking step after aluminum deposition even if the film thickness is increased. As a result of intensive studies on a filming agent for a cathode ray tube having good decomposability, the present invention has been reached. That is, the present invention is a filming agent for a cathode ray tube, comprising a polyalkylene carbonate.

The polyalkylene carbonate in the present invention includes, for example, polyethylene carbonate, polypropylene carbonate, polytrimethylene carbonate, poly-1,4-butylene carbonate, poly1,2-
Butylene carbonate, poly 1,2-isobutylene carbonate, poly 1,5-heptylene carbonate, 1,
2-heptyrene carbonate, poly 1,6-hexylene carbonate, poly 1,2-hexylene carbonate,
Examples include polyphenylethylene carbonate, polycyclohexylene carbonate, polymethoxyethylene carbonate, polyphenoxyethylene carbonate, and copolymers thereof. Of these, preferred are those represented by the general formula (1): -CHR ₁ -CHR ₂ -OCO _2- (1) (wherein R ₁ and R ₂ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, A polyalkylene carbonate having a structural unit represented by a phenyl group, an alkoxy group, or a phenoxy group), and particularly preferred are polyethylene carbonate and polypropylene carbonate.

The weight average molecular weight of (A) used in the present invention is usually from 5,000 to 500,000,
Preferably, it is 10,000 to 200,000. If the weight average molecular weight is less than 5,000, the film-forming property becomes insufficient, and if it exceeds 500,000, the solution viscosity becomes high when used after being dissolved in a solvent to form a smooth coating film on the panel. Becomes difficult.

The method of synthesizing (A) is not particularly limited, and examples thereof include a method of copolymerizing an epoxy compound and carbon dioxide with a zinc-based catalyst, and a method of transesterifying a diol with an organic carbonate.

The filming agent comprising (A) of the present invention is obtained by dissolving (A) in an organic solvent and dispersing (A) in an aqueous medium in the presence or absence of an emulsifier. It may be used in any form of emulsified emulsion.

As a solvent when used as a solution,
Aromatic hydrocarbons (such as toluene and xylene), ester compounds (such as ethyl acetate and ethyl cellosolve), ketone compounds (such as acetone and methyl ethyl ketone), and ether compounds (such as diglyme) can be used. Preferred of these are toluene and xylene. In this case, the solid content concentration is usually 5 to 30.
% And its viscosity at 25 ° C. is usually 1 to 50 centipoise.

When used in the form of an emulsion, the method of emulsification is not particularly limited, but a method in which (A) is emulsified under high pressure in an aqueous medium at a temperature equal to or higher than the melting point or a method in which fine powder physically ground in an aqueous medium is used. Dispersion method is mentioned. The form of the aqueous emulsion is more preferred from the viewpoint that the working environment and the equipment do not require explosion-proof measures. When used in the form of an aqueous emulsion, a water-soluble polymer, aqueous hydrogen peroxide, a surfactant and the like can be added as necessary.

Examples of the water-soluble polymer include polyvinyl alcohol, boric acid esters of polyvinyl alcohol, polyethylene glycol and polypropylene glycol. Of these, polyvinyl alcohol and boric acid esters of polyvinyl alcohol are preferred. When the water-soluble polymer is added, the amount of the water-soluble polymer may be 100
It is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight based on parts by weight.

The amount of the hydrogen peroxide solution to be added is usually 0.1 to 30 parts by weight, preferably 0.5 to 15 parts by weight based on 100 parts by weight of the polyalkylene carbonate as a 35% aqueous solution. is there.

Examples of the surfactant include nonionic surfactants such as nonylphenol ethylene oxide adduct, lauryl alcohol ethylene oxide adduct and polyethylene glycol (molecular weight: 400 to 1,000) lauric acid monoester, dodecylbenzene sulfone And anionic surfactants such as sodium laurate and sodium lauryl alcohol sulfate. Of these, preferred are nonylphenol ethylene oxide 10 to 20 mol adduct and lauryl alcohol ethylene oxide 10 to 20 mol adduct. When the surfactant is added, the amount is usually 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the polyalkylene carbonate.

By adding these additives, the stability of the emulsion, the optimization of the viscosity, the wettability to the panel surface, the uniformity of coating and the leveling property are improved, and the quality of the film formed by coating is further improved. be able to.

The filming agent of the present invention can be used in combination with a conventionally used polyacrylate material or the like as long as its properties are not impaired.

The method of using the filming agent for a cathode ray tube of the present invention is as follows. First, a filming agent in the form of an aqueous emulsion or a solvent solution is applied to the panel on which the phosphor has been formed by using a coating machine such as a spin coater or a spray coater. A uniform and flat coating film is formed on the body layer. The film thickness is usually 7 to 15 microns. Next, a vapor deposition film of aluminum is formed on the coating film in a thickness of 0.3 to 0.5 μm by vacuum vapor deposition. Then, the organic component used in the filming step is subjected to 3 baking in the baking step.
By performing the thermal decomposition at 50 to 450 ° C., a panel in which a flat aluminum vapor-deposited film is formed on the phosphor is obtained.

The greatest advantage of the filming agent for a cathode ray tube of the present invention is that it has good thermal decomposability. That is, the thermal decomposition onset temperature of the polyacrylate material used for this application is generally 290 to 320 ° C., whereas the filming agent of the present invention has a thermal decomposition start temperature of 210 to 260 ° C.
° C, the thermal decomposability in the baking step is very good, and no unburnt phenomenon occurs.

[0018]

EXAMPLES The present invention will be described below in detail with reference to examples, but the scope of the present invention is not limited by these examples.

Example 1 Polypropylene carbonate (manufactured by PAC POLYMERS INC.)
"QPAC 40M", weight average molecular weight 50,000) 300
g, 10 g of Nonipol 200 (manufactured by Sanyo Chemical Industries, nonylphenol-based nonionic surfactant) and 690 g of ion-exchanged water were emulsified at 150 ° C. for 1 hour in a pressure-resistant closed vessel. To 1,000 g of the obtained emulsion, polyvinyl alcohol (degree of polymerization 2,500, saponification rate 85%)
3 g, 10 g of 35% hydrogen peroxide solution and ion-exchanged water 5
The solid content concentration was adjusted to 20% by weight by adding 55 g to obtain an aqueous emulsion 1 having a viscosity of 5 centipoise / 25 ° C. The aqueous emulsion 1 was applied to a panel with a phosphor by a spin coater and dried at 50 ° C. for 5 minutes to form a film made of polypropylene carbonate on the phosphor surface. Next, after baking aluminum on the film by a conventional method, baking was performed under the conditions shown in Table 1 to thermally decompose organic components. After the baking, no unburnt film was observed on the surface on which the deposited aluminum film was formed. Then, frit sealing was performed to complete the cathode ray tube, and the luminance of the cathode ray tube was measured. The results are shown in Table 1.

Example 2 Polyethylene carbonate (Air Products and Chemica)
ls Inc.'s "QPACBinders" weight average molecular weight 50,000)
300 g, Nonipol 140 (manufactured by Sanyo Chemical Industries, nonylphenol-based nonionic surfactant) 10 g, and 690 g of ion-exchanged water were emulsified under high pressure at 150 ° C. for 1 hour in a pressure-tight closed vessel. In 1,000 g of the obtained emulsion,
Polyvinyl alcohol (degree of polymerization 2,500, saponification rate 8
5%) 3 g, 35 g of hydrogen peroxide solution 10 g and ion-exchanged water 555 g were added to adjust the solid concentration to 20% by weight to obtain an aqueous emulsion 2 having a viscosity of 5 centipoise / 25 ° C. The aqueous emulsion 2 was applied to a panel with a phosphor by a spin coater, and a phosphor panel on which aluminum was deposited was prepared in the same manner as in Example 1 except that the baking temperature was 350 ° C. No burn residue of the film was observed on the surface on which the aluminum vapor-deposited film was formed. And frit seal is done to complete the cathode ray tube,
The brightness of the cathode ray tube was measured. The results are shown in Table 1.

Example 3 Polypropylene carbonate (PAC POLYMERS INC.)
70 g of “QPAC 40M” (weight average molecular weight: 50,000) was uniformly dissolved in 930 g of toluene to obtain a filming agent solution 1 having a viscosity of 10 centipoise / 25 ° C. The solution 1 was applied to a panel with a phosphor using a spray coater and dried to form a film made of polypropylene carbonate on the phosphor surface. Thereafter, a phosphor panel on which aluminum was deposited was prepared in the same manner as in Example 1. No burn residue of the film was observed on the surface on which the aluminum vapor-deposited film was formed. Then, frit sealing was performed to complete the cathode ray tube, and the luminance of the cathode ray tube was measured. The results are shown in Table 1.

Example 4 375 g of a polyacrylate aqueous emulsion (solid content: 40% by weight) composed of methyl methacrylate, ethyl acrylate, and methacrylic acid was added to polyvinyl alcohol (polymerization degree: 2,500, saponification rate: 85%). ), 5 g of colloidal silica, 5 g of 35% hydrogen peroxide solution and trace amounts of ammonia water and 415 g of ion-exchanged water for adjusting the pH to 7 to give a solid content concentration of 2
An aqueous emulsion 3 adjusted to 0% by weight was obtained. Then, 805 g of the aqueous emulsion 1 prepared in Example 1
805 g of the aqueous emulsion 3 was added to
An aqueous emulsion 4 having a viscosity of 4 centipoise / 25 ° C. at 0% by weight was obtained. The aqueous emulsion 4 was applied to a phosphor-equipped panel by a spin coater, and a phosphor panel on which aluminum was deposited was prepared in the same manner as in Example 1 below.
Almost no burning residue of the film was observed on the surface on which the aluminum vapor-deposited film was formed. Then, frit sealing was performed to complete the cathode ray tube, and the luminance of the cathode ray tube was measured.
The results are shown in Table 1.

COMPARATIVE EXAMPLE 1 375 g of a polyacrylate aqueous emulsion (solid content: 40% by weight) comprising methyl methacrylate, ethyl acrylate, and methacrylic acid was added to polyvinyl alcohol (polymerization degree: 2,500, saponification rate: 85%). ), 5 g of colloidal silica, 5 g of 35% hydrogen peroxide solution and a small amount of ammonia water for adjusting the pH to 7 and 615 g of ion-exchanged water to obtain a solid content concentration of 1
The aqueous emulsion 5 was obtained by adjusting to 6% by weight. The aqueous emulsion 5 was applied to a panel with a phosphor by a spin coater, and a phosphor panel on which aluminum was deposited was prepared in the same manner as in Example 1 below. Almost no burning residue of the film was observed on the surface on which the aluminum vapor-deposited film was formed. Then, frit sealing was performed to complete the cathode ray tube, and the luminance of the cathode ray tube was measured. The results are shown in Table 1.

Comparative Example 2 375 g of a polyacrylate aqueous emulsion (solid content: 40% by weight) composed of methyl methacrylate, ethyl acrylate, and methacrylic acid was added to polyvinyl alcohol (degree of polymerization 2,500, saponification rate 85%). ), 5 g of colloidal silica, 5 g of 35% hydrogen peroxide solution and trace amounts of ammonia water and 415 g of ion-exchanged water for adjusting the pH to 7 to give a solid content concentration of 2
By adjusting the amount to 0% by weight, an aqueous emulsion 6 was obtained. The aqueous emulsion 6 was applied to a panel with a phosphor by a spin coater, and a phosphor panel on which aluminum was deposited was prepared in the same manner as in Example 1 below. The burnt residue of the light brown film was generated on the surface on which the aluminum vapor-deposited film was formed. And frit seal is done to complete the cathode ray tube,
The brightness of the cathode ray tube was measured. The results are shown in Table 1.

[0025]

[Table 1] Measuring method Residual burning of film: Visual judgment Luminance: According to JIS C-7614-70.

[0026]

By using the filming agent for a cathode ray tube comprising the polyalkylene carbonate of the present invention, the thermal decomposition temperature can be reduced in the panel baking step as compared with the conventional one, and the unburned film remains after baking. Is not generated, and the luminance of the cathode ray tube can be improved.

Claims (4)

(57) [Claims] 1. A filming agent for a cathode ray tube, comprising a polyalkylene carbonate (A). 2. The method of claim 2, wherein (A) is a compound represented by the following general formula (1): —CHR ₁ —CHR ₂ —OCO ₂ — (1) (wherein R ₁ and R ₂ are a hydrogen atom, The filming agent according to claim 1, which has a structural unit represented by an alkyl group, a phenyl group, an alkoxy group, or a phenoxy group). 3. The filming agent according to claim 1, wherein (A) is at least one selected from polyethylene carbonate and polypropylene carbonate. 4. The weight average molecular weight of (A) is 5,000.
The filming agent according to any one of claims 1 to 3, which is 0 to 500,000.