JPH07238239A - Phosphor paste composition - Google Patents

Abstract

(57) [Summary] [Structure] (a) Alkyl Methacrylate, (b) Unsaturated Carboxylic Acid, and (c) Alkyl Polymer (A) Consisting of Other Copolymerizable Vinyl Monomer, and (d) Alkyl Methacrylate, (E) Amino group-containing alkyl (meth)
100 parts by weight of an acrylic polymer mixture composed of an acrylate and (f) an acrylic polymer (B) composed of another copolymerizable vinyl monomer, and phosphor fine powder and an organic solvent having a boiling point of 150 ° C. or higher. Viscosity 50
~ 300 poise phosphor paste composition. [Effect] It is possible to obtain a phosphor film having high brightness, high resolution, and good baking property.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a cathode ray tube (hereinafter referred to as CR
(Hereinafter abbreviated as T) phosphor composition used for forming a phosphor film having high brightness and high resolution on the phosphor surface.

[0002]

2. Description of the Related Art CRT represented by a cathode ray tube of a television
Is composed of a phosphor surface, a funnel and an electron gun. And, this CRT is one in which an electron beam emitted from an electron gun collides with a phosphor surface and phosphor particles in the phosphor surface are excited to emit light to display the light, which is the oldest among electronic displays.

With the development of electronics in recent years, various visual devices have been diversified, and various types of CRTs such as color CRTs, monochrome CRTs, large CRTs to ultra-compact CRTs are manufactured. Further, in recent years, other electronic displays such as liquid crystals have increased their shares, but CRTs still have a large share in various visual devices because CRTs are more advantageous in terms of manufacturing cost and productivity.

C used in such visual equipment
Of the RTs, the phosphor film on the phosphor surface has a great influence on the CRT performance such as high brightness and high resolution.
Known methods for producing a phosphor film used in a monochrome CRT include a slurry method, a precipitation method, an electrodeposition method, and a vapor deposition method. As a method of manufacturing a phosphor film used in a high resolution CRT for a monochrome monitor, a precipitation method has been generally used conventionally. However, when a phosphor film is obtained by the sedimentation method, there is a drawback that the surface thereof has few irregularities and it is difficult to efficiently form a phosphor film having a uniform thickness.

On the other hand, the phosphor surface used for a color CRT is generally a CR film which is a phosphor film in which phosphor particles of three colors of red, green and blue are arranged in dots or stripes.
It is attached to the T front panel to form a phosphor surface, and the phosphor particles in the phosphor film are caused to emit light by causing an electron beam to collide with the phosphor surface. As a method of manufacturing the phosphor film used for the color CRT, a photo-curing printing method using a shadow mask has been conventionally used.

However, in order to manufacture an excellent phosphor film of high resolution by the photo-curing printing method, it is indispensable to use a shadow mask having a fine pattern. In other words, as the color CRT becomes smaller and the higher definition screen is required, the higher definition shadow mask is required, and the technical difficulty of its production is accompanied.

In addition, in the printing method, when the phosphor film is formed, the phosphor paste composition and the phosphor contained in the phosphor paste composition which are excessively generated on the portion other than the phosphor film forming surface of the CRT are recovered. However, it has a drawback that it is troublesome and causes a large loss, resulting in high cost in terms of material and other productivity. Therefore, in order to solve the above-mentioned drawbacks, Japanese Patent Publication No.
A method of forming a phosphor surface by a printing method described in Japanese Patent No. 23231 and Japanese Patent Laid-Open No. 59-21377 is proposed.

The printing method refers to a phosphor paste composition for printing such as white, red, green and blue, which comprises a binder resin, phosphor particles, and a solvent used for adjusting the viscosity of the phosphor paste. , Printing directly or indirectly on a CRT front panel using a shadow mask to fix a predetermined color at a predetermined place to form a phosphor film, and then removing the binder resin component in the paste composition by baking. The method is characterized by producing a phosphor surface. Examples of the binder resin include cellulose-based resins and vinyl alcohol-based resins. However, since the baking temperature is high and the baking residue is likely to remain in the phosphor film in both cases, this baking is performed when the obtained phosphor surface is illuminated. There are many practical problems such as the residue becoming a black spot and adversely affecting the life of the CRT.

Further, Japanese Patent Application Laid-Open No. 2-77477 proposes a printing phosphor paste composition using an acrylic resin as a binder resin having a good baking property. The paste composition has good leveling property. As a result, the printed phosphor film becomes thick, and the phosphor film surface with high brightness and high resolution, which is the target of the present invention, cannot be realized.

[0010]

As represented by high-definition televisions in recent years, with the increase in resolution of CRTs,
Since the brightness is lowered, there is an increasing demand for a phosphor surface having high resolution and high brightness. As a means for solving this requirement, in order to reduce the thickness of the phosphor film, it is necessary to uniformly arrange the phosphor particles in the phosphor film to a thickness of 1 to 3 layers. However, in the currently known phosphor paste composition for printing, when an attempt is made to form a thin phosphor film as described above, the leveling force of the paste composition is insufficient and pinholes are formed in the formed film. Occurs, and a uniform phosphor surface cannot be formed. Also,
A phosphor paste composition using a binder resin having a functional group introduced in order to increase the affinity between the phosphor particles and the binder resin and improve the leveling property is disclosed in JP-A-2-77.
However, even with this phosphor paste composition, it has not been possible to form a thin high-brightness phosphor film in which phosphor particles are uniformly arranged in one to three layers.

That is, in order to make the thickness of the phosphor film in which the phosphor particles are uniformly arranged in one to three layers on the phosphor surface obtained by the printing method, the phosphor paste composition for printing is used. The dispersibility of the phosphor particles is good, the phosphor particles are leveled uniformly after printing the composition, and
A binder resin that is completely decomposed in the baking process after drying and has no baking residue is essential. Further, in order to form a phosphor surface by a printing method using the phosphor paste composition, it is necessary to satisfy the printing suitability such as the viscosity and thixotropy of the phosphor paste composition for printing, and currently satisfy such performance. At present, the paste composition has not been found.

[0012]

The object of the present invention is to provide a high level of brightness, high resolution, and long life without impairing the good thermal decomposability of the acrylic binder resin. Another object of the present invention is to provide a phosphor paste composition that can provide a CRT having a different phosphor film.

That is, the gist of the present invention is as follows: (A) (a) alkyl methacrylate 65 to 99.5% by weight, (b) unsaturated carboxylic acid 0.5 to 15% by weight,
(C) 0 to 20% by weight of another copolymerizable vinyl monomer
10-80% by weight of an acrylic polymer obtained by polymerizing a monomer mixture consisting of (B) (d) alkyl methacrylate 60-99.75
Acrylic system obtained by polymerizing a monomer mixture consisting of 10% by weight, (e) 0.25 to 20% by weight of amino group-containing alkyl (meth) acrylate, and (f) 0 to 20% by weight of another copolymerizable vinyl monomer. Polymer 90 to 20% by weight
And 100 parts by weight of an acrylic polymer mixture consisting of It is in.

As the binder resin component used in the present invention, an acrylic polymer (A) comprising the components (a) to (c) described below and the components (d) to (d) described below.
An acrylic polymer mixture comprising the acrylic polymer (B) comprising the component (f) is used.

First, the alkyl methacrylate which is the component (a) which constitutes the component (A) used in the present invention is the starting temperature of firing of the phosphor film formed from the phosphor paste composition of the present invention, the complete firing temperature, It is a component necessary for applying the heat loss rate and the like to necessary conditions, and may be arbitrarily selected according to the purpose. Specific examples of the component (a) include:
Examples thereof include alkyl methacrylate having an alkyl group having 1 to 8 carbon atoms such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate and isobutyl methacrylate.

The alkyl methacrylate used as the component (a) in the present invention must be copolymerized in the component (A) at a proportion of 65 to 99.5% by weight. Since the phosphor film formed by using the phosphor paste composition made of the binder resin in which the copolymerization amount of the component (a) is less than 65% by weight is deteriorated in the baking property, baking residues are left in the phosphor film. Remaining brightness is lowered, which is not preferable. Further, when a phosphor film is formed using a phosphor paste composition made of a binder resin in which the copolymerization amount of the component (a) exceeds 99.5% by weight, the dispersibility of the phosphor particles in the binder resin is improved. Due to the defect, the phosphor particles cannot be formed into a thin film of 1 to 3 layers.

The unsaturated carboxylic acid which is the component (b) constituting the component (A) used in the present invention is not particularly limited, but specific examples thereof include (meth) acrylic acid, itaconic acid, fumaric acid and maleic acid. Etc. The unsaturated carboxylic acid as the component (b) is copolymerized in the component (A) at a ratio of 0.5 to 15% by weight. When a phosphor film is formed by using a phosphor paste composition made of a binder resin having a copolymerization amount of the component (b) exceeding 15% by weight, the baking property is deteriorated. Remains, and brightness is reduced, which is not preferable. Further, the phosphor paste composition made of a binder resin having a copolymerization amount of the component (b) of less than 0.5% by weight has a poor leveling property. A good phosphor film cannot be obtained.

The component (c) constituting the component (A) used in the present invention can be used within a range that does not impair the baking properties of the binder resin. Specific examples of the component (c) include, for example, alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate, and other vinyl acetate, ethoxy vinyl acetate, vinyl propionate, methyl vinyl ether, ethyl vinyl ether, isopropyl vinyl ether, n-propyl vinyl ether, methyl vinyl ketone, ethyl vinyl ketone, isopropyl vinyl ketone,
γ-methacryloxypropyltris (β-methoxyethoxy) silane, methacryloxymethyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-vinyl Benzoic acid, p-vinylbenzoic acid, 2,4-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, N-vinylpyrrolidone and the like can be mentioned.

As the component (c), a copolymerizable monovinyl monomer other than the above-mentioned components (a) and (b) can be copolymerized in the component (A) up to 20% by weight. The binder resin obtained by copolymerizing the component (c) in an amount of more than 20% by weight has poor baking properties and dispersibility of phosphor particles.

Next, the alkyl methacrylate which is the component (d) which constitutes the component (B) used in the present invention is the starting temperature and the complete firing temperature of the phosphor film made of the phosphor paste composition of the present invention. The heat loss rate and the like may be arbitrarily selected so as to meet the necessary conditions.

Specific examples of the component (d) include methylmethacrylate, ethylmethacrylate, n-butylmethacrylate, isobutylmethacrylate, and alkylmethacrylate having an alkyl group having 1 to 8 carbon atoms. The alkyl methacrylate of the component (d) used in the present invention is 60 to 99.75 in the component (B).
It is necessary to copolymerize at a weight percentage.
When a phosphor film is formed using a phosphor paste composition made of a binder resin in which the copolymerization ratio of the component (d) is less than 65% by weight, the baking property of the phosphor film is lowered, and the baking residue remains in the obtained phosphor film. Remains, and brightness is reduced, which is not preferable.
Further, a phosphor paste composition made of a binder resin in which the copolymerization ratio of the component (d) exceeds 99.75 wt% is not preferable because the dispersibility of the phosphor particles in the binder resin is poor.

The amino group-containing alkyl (meth) acrylate, which is the component (e) constituting the component (B) used in the present invention, is a component that contributes to the dispersibility of the phosphor particles in the binder resin. Specific examples of the component (e) include, for example, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dimethylaminobutyl (meth) acrylate, diethylaminoethyl (meth) acrylate, diethylaminopropyl (meth) acrylate, Diethylaminobutyl (meth)
Dialkylaminoalkyl (meth) acrylates having an alkyl group having 1 to 4 carbon atoms such as acrylate, ethylmethylaminoethyl (meth) acrylate, ethylmethylaminopropyl (meth) acrylate, ethylmethylaminobutyl (meth) acrylate, etc. Can be mentioned.

The amino group-containing alkyl (meth) acrylate of the component (e) used in the present invention must be copolymerized in the component (B) in a proportion of 0.25 to 20% by weight. When a phosphor film is formed by using a phosphor paste composition made of a binder resin having a copolymerization amount of the component (e) exceeding 20% by weight, the baking property of the phosphor film is lowered, and the resulting phosphor film is baked. Luminance is reduced due to the residue, which is not preferable. Further, a phosphor paste composition made of a binder resin in which the copolymerization amount of the component (e) is less than 0.25% by weight is not preferable because the dispersibility of the phosphor particles in the binder resin is poor.

As the component (f) constituting the component (B) used in the present invention, a copolymerizable monovinyl monomer other than the above-mentioned components (d) and (e) is used within a range that does not impair the firing property. It is possible.

Specific examples of the component (f) include alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate and butyl acrylate, and other vinyl acetate, vinyl ethoxy acetate, vinyl propionate, methyl vinyl ether and ethyl. Vinyl ether, isopropyl ether, n-propyl vinyl ether, methyl vinyl ketone, ethyl vinyl ketone, isopropyl vinyl ketone, γ-methacryloxypropyltris (β-methoxyethoxy) silane, methacryloxymethyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxy Silane, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-vinylbenzoic acid, p-vinylbenzoic acid, 2,4
-Dimethylstyrene, 3,4-dimethylstyrene, 3,
Examples thereof include 5-dimethylstyrene, N-vinylpyrrolidone, (meth) acrylamide, N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide and the like.

The above-mentioned monomers can be used alone or in combination of two or more as long as the baking property of the copolymerized resin does not occur. In the present invention, as the component (f), a copolymerizable monovinyl monomer other than the components (d) and (e) can be used in the component (B) up to 20% by weight.

Further, in the phosphor paste composition of the present invention, as long as the baking property of the acrylic polymer mixture (hereinafter referred to as an acrylic binder resin) comprising the components (A) and (B) is not impaired ( A) component and /
Alternatively, a polyfunctional crosslinking monomer may be copolymerized in the component (B). The mixing ratio of the acrylic binder resin of the present invention is such that (A) component: (B) component is from 10 to 80:90.
10 to 10 (% by weight).

In the phosphor film formed by using the phosphor paste containing the acrylic binder resin in which the component (A) exceeds 80% by weight, the leveling of the phosphor particles is poor, so that the phosphor particles are uniform. Are not arranged, and pinholes are generated in the phosphor film, which is not preferable. Also, (A)
A phosphor film formed from a phosphor paste using an acrylic binder resin whose content is less than 10% by weight has a poor reproducibility of the printed pattern. Therefore, a fine pattern can be accurately formed to form the phosphor film. It is not preferable because it cannot be obtained.

The type of the phosphor particles as the component (C) used in the present invention is not particularly limited, and may be arbitrarily selected according to the purpose. When a phosphor film for a high-resolution CRT having less unevenness and good light emission efficiency is manufactured using the phosphor paste composition of the present invention, specifically, the volume average particle diameter of the monochrome phosphor particles is 1 to 4 μm, and the color is It is preferable that the phosphor particles have a volume average particle diameter of 1 to 9 μm and have not been finely divided by pulverization or the like.

The component (C) used in the present invention is added in the range of 200 to 500 parts by weight with respect to 100 parts by weight of acrylic binder resin (solid content 100%). Here, in a phosphor paste composition in which the amount of phosphor particles added is less than 200 parts by weight, the number of phosphor particles is insufficient, and it is difficult to form a uniform phosphor film, which is not preferable. Also,
In a phosphor paste composition having a phosphor particle content of more than 500 parts by weight, the amount of the acrylic binder resin is insufficient, so that the leveling property of the phosphor formed from the paste composition is deteriorated and a printed coating film is formed. Pinholes occur,
It is not preferable because a uniform phosphor film cannot be obtained such as unevenness on the phosphor film surface.

The phosphor paste composition of the present invention may contain an organic solvent having a boiling point of 150 ° C. or higher as the component (D) in order to adjust the viscosity of the paste composition. The viscosity of the phosphor paste composition of the present invention, in terms of coatability,
It may be adjusted to about 50 to 300 poise.

The paste composition having a viscosity of less than 50 poise has too large a fluidity and is likely to cause bleeding at the edges of the phosphor film obtained after printing the phosphor film, resulting in poor reproducibility of the printed pattern. Absent. Further, the paste composition having a viscosity of more than 300 poises is not preferable because its fluidity is lowered and the resulting phosphor film surface has irregularities. A phosphor paste composition using an organic solvent having a boiling point of lower than 150 ° C. causes a change in viscosity of the paste composition with time during printing of the phosphor film, which results in formation of a phosphor film having uniform characteristics. This is difficult and not preferable.

Specific examples of the component (D) include, for example, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate,
2,2,4-trimethyl 1,3-pentadiol monoisobutylate, isophorone, 3-methoxybutyl acetate and the like can be mentioned. To the phosphor paste composition of the present invention, various additives such as a generally known plasticizer, dispersion stabilizer, leveling agent, and thixotropy imparting agent may be added as long as the purpose is not impaired.

[0034]

EXAMPLES The present invention will be described below with reference to examples.
In the examples, "part" means "part by weight" and "%" means "% by weight". The description of phosphor particles and activator is described in JEDEC.
RNA numbers based on.

The symbols in the examples and tables indicate the following. iBMA: isobutyl methacrylate MAA: methacrylic acid DMAEMA: N, N-diethylaminoethyl methacrylate St: styrene Viscosity of the phosphor paste composition: 25 ° C, measured with an E-type viscometer (manufactured by Tokyo Keiki Co., Ltd.).

[Evaluation of phosphor film surface] Concealing property, smoothness,
An optical microscope (50 to 400 times) using both transmitted light and reflected light was used for printing accuracy and baking properties, and an electron microscope (3500) was used for the cross section of the phosphor surface for the phosphor film thickness.
The following evaluation was carried out using Concealment: Using both transmitted light and reflected light, the presence or absence of pinholes in the phosphor film was examined with an optical microscope. ◯: No pinholes Δ: With pinholes ×: With many pinholes Phosphor film thickness: The cross section of the phosphor film was measured using an electron microscope. Smoothness: Using oblique light, optical microscope (50 times, 100
The surface roughness of the phosphor film was examined by multiplying the magnification by 400 times. ○: No unevenness and no shade caused by oblique light. Δ: There are some irregularities, and shade is observed due to oblique light. ×: There are many irregularities, the generation of shade due to oblique light is clearly seen, and there are screen mesh marks. Printing accuracy: 10 mm x 1 with # 400 mesh screen
A 0 mm pattern was printed, and the dimensional change of the transfer pattern and the presence or absence of bleeding at the pattern edge portion were examined. ○: Dimensional change of ± 5% or less, no bleeding at the pattern edge. ×: Dimensional change of ± 5% or more, bleeding at pattern edge. Baking property: About 10 mg of the phosphor paste composition was used to bake from room temperature to 500 ° C. (heating rate 15 ° C./min) while gradually raising the baking temperature. ○: No baking residue. ×: There are many baking residues, colored black.

[Example 1] <Polymerization of acrylic resin solution A> 98 parts of iBMA, MA
A2 parts and azobisisobutyronitrile 2 parts, diethylene glycol monobutyl ether acetate 18
A reaction was carried out in 5 parts at 80 ° C. for 10 hours to obtain an acrylic resin solution A (weight average molecular weight 180,000, solid content 35%).

<Polymerization of acrylic resin solution B> iBMA
Acrylic resin solution B (weight average molecular weight 150,000, weight average molecular weight 150,000, 95 parts, DMAEMA 5 parts, and azobisisobutyronitrile 1 part, except that 185 parts of diethylene glycol monobutyl ether acetate was used.
35% solids) were obtained.

<Preparation of Monochrome Phosphor Paste Composition>
100 parts by weight of acrylic resin solution A (solid content 35%),
In a mixture with 100 parts of acrylic resin solution B (solid content 35%), P-45 monochrome phosphor fine powder (Y ₂ O ₂ S: T) was added.
b, volume average particle diameter 2 μm) 200 parts are dispersed and kneaded,
The viscosity was adjusted to 110 poise with diethylene glycol monobutyl ether acetate to obtain a monochrome phosphor paste composition. The obtained phosphor paste composition was applied on a glass plate by a screen printing method to a thickness of 10 μm using a # 400 mesh screen plate, dried at 150 ° C. for 60 minutes, and then at 450 ° C. for 30 minutes. It was baked for a minute to obtain a phosphor surface. As a result of evaluating the state of the surface of the phosphor film obtained as described above, it was found that there was no pinhole and a smooth surface having complete concealing property was formed. The thickness of the phosphor film was about 4.5 μm.

[Examples 2 and 3, Comparative Examples 1 and 2] A phosphor surface was obtained in the same manner as in Example 1 except that the mixing ratio of the acrylic resin solution A and the acrylic resin solution B was changed to the ratio shown in Table 1. It was Table 1 shows the evaluation results of the obtained phosphor film surface.

[0041]

[Table 1]

[Examples 4 to 6 and Comparative Examples 3 to 5] Acrylic resin solution A'was synthesized in the same manner as acrylic resin solution A except that the monomers shown in Table 2 were used, and fluorescence was obtained in the same manner as in Example 1. I got a body surface. The evaluation results of the obtained phosphor film surface are shown in Table 2.

[0043]

[Table 2]

[Examples 7 to 9 and Comparative Examples 6 to 8] Acrylic resin solution B'was synthesized in the same manner as acrylic resin solution A except that the monomers shown in Table 3 were used. I got a body surface. The evaluation results of the obtained phosphor film surface are shown in Table 3.

[0045]

[Table 3]

[Examples 10 and 11, Comparative Examples 9 and 10] Acrylic polymer mixture consisting of 100 parts of acrylic resin solution A (100% solid content) and 100 parts of acrylic resin solution B (100% solid content), and monochrome fluorescence. A phosphor surface was obtained in the same manner as in Example 1 except that the body particles were used in the ratio shown in Table 4. Table 4 shows the evaluation results of the obtained phosphor film surface.
Shown in.

[0047]

[Table 4]

[Examples 12 and 13, Comparative Examples 11 and 12]
A phosphor surface was obtained in the same manner as in Example 1 except that the viscosity of the phosphor paste composition was adjusted to the value shown in Table 5 by using diethylene glycol monoethyl ether acetate as a diluent. Table 5 shows the evaluation results of the obtained phosphor film surface.
Shown in.

[0049]

[Table 5]

Comparative Example 13 Polymerization in a toluene solvent to synthesize an acrylic resin, a phosphor paste composition was prepared using the acrylic resin, and the paste composition was prepared by using toluene as a diluent. A phosphor surface was obtained in the same manner as in Example 1. As a result of evaluating the state of the obtained phosphor surface, toluene volatilized during printing the paste composition on a glass plate, the viscosity of the paste composition increased, the phosphor particles could not be leveled, and the hiding property And the smoothness was poor.

As described above in detail, by using the phosphor paste composition of the present invention, it becomes possible to obtain a CRT having a phosphor surface which is excellent in baking property and is excellent in brightness and resolution. The industrial effect is extremely large.

Claims (1)

[Claims] 1. An (A) (a) alkyl methacrylate 65.
To 99.5% by weight, (b) unsaturated carboxylic acid 0.5 to 1
5% by weight, (c) other copolymerizable vinyl monomer 0 to
10 to 80% by weight of an acrylic polymer obtained by polymerizing a monomer mixture of 20% by weight, and (B) (d) an alkyl methacrylate 60 to 99.75.
Acrylic system obtained by polymerizing a monomer mixture consisting of 10% by weight, (e) 0.25 to 20% by weight of amino group-containing alkyl (meth) acrylate, and (f) 0 to 20% by weight of another copolymerizable vinyl monomer. Polymer 90 to 20% by weight
And 100 parts by weight of an acrylic polymer mixture consisting of .