JPH10168267A - Emulsion composition for forming crt metal back undercoat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an emulsion which can permit the production of a highly fine and bright CRT because the undercoat on which a metallized film has been formed can be baked without causing the blistering of the film and can evaporate in the form of a heat decomposition gas by specifying the ratio of the particle diameter of an aqueous emulsion polymer to that of an aqueous emulsion acrylic polymer and specifying the mixing ratio between these polymers. SOLUTION: An aqueous emulsion polymer (A) comprising at least one unsaturated carboxylic acid selected among alkyl methacrylate with a 1-4C alkyl, an alkyl acrylate with a 1-4C alkyl, acrylic acid, etc., and having a particle diameter of 0.05-0.2μm and a small amount of an aqueous acrylic emulsion polymer (B) having a particle diameter larger than that of component A are added. The particle diameter is 0.4-5μm, the ratio of the particle diameter of component A to that of component B is 1:3 to 1.65, has a lowest film-forming temperature higher than that of component A and is used in an amount of 0.1-10 pts.wt. per 100 pts.wt. component A. This emulsion is used as a metal back undercoat material in the formation of a metal deposition film on the phosphor layer of a CRT.

Description

DETAILED DESCRIPTION OF THE INVENTION

TECHNICAL FIELD The present invention relates to a cathode ray tube (hereinafter, referred to as a cathode ray tube).
The present invention relates to an emulsion composition for forming a metal back undercoat film, which is used as a base when forming a metal deposition film of aluminum or the like after forming a phosphor layer on the inner surface of a CRT panel in the production of a CRT panel.

[0002]

2. Description of the Related Art CRTs have been used for various applications as displays. However, with the recent diversification and higher density of information, higher performance, especially high-definition display, is required. . However, the higher the definition is, the lower the luminance is, and the practicality is naturally limited in obtaining a high definition and high resolution CRT.

Conventionally, a CRT has a phosphor layer formed on the inner surface of a CRT panel, and then a metal reflection film formed by depositing a metal such as aluminum to reflect light emitted from the inner surface of the CRT panel to the metal reflection film. In this case, a method of improving the brightness of the front surface of the CRT has been adopted. However, in this method, even if a metal deposited film of aluminum or the like is directly formed on the surface of the phosphor layer, a metal back layer having a mirror effect cannot be obtained due to unevenness of the surface of the phosphor layer. Light could not be reflected efficiently.

Accordingly, in recent years, a method has been adopted in which an organic material layer is applied to a phosphor layer to smooth the unevenness of the surface of the phosphor layer, and then a metal reflection film is formed. Specifically, first, a metal back undercoat material (hereinafter, referred to as an undercoat material) is applied to the phosphor layer and dried to form a metal back undercoat film (hereinafter, referred to as an undercoat film). After the layer has been smoothed in advance (hereinafter, this undercoat film forming process is referred to as filming process), a metal deposition film is formed thereon, and then the undercoat film is removed by baking treatment by baking treatment. And a method of forming a metal reflection film.

For example, Japanese Patent Publication No. 47-24416 discloses an undercoat material comprising an acrylic emulsion, a poval borate complex and hydrogen peroxide.
According to this method, cracks and pores are formed around the phosphor in the phosphor layer by the action of the poval borate complex and hydrogen peroxide, and holes for releasing gas generated during the baking treatment of the undercoat film ( By forming a pinhole in a metal vapor-deposited film, the metal reflective film is prevented from being blistered during baking of the undercoat film. However, in this method, the number of pinholes at the contact portion between the undercoat film and the phosphor layer surface is not sufficient, and the film thickness must be increased in order to improve the smoothness of the undercoat film. Is required,
Since the amount of volatile gas generated during the baking treatment of the undercoat film increases due to the increase in the thickness of the undercoat film, if the baking rate of the undercoat film is increased to increase the productivity of the CRT, the metal reflective film may not be fluorescent. Since phenomena such as "aluminum floating" and "aluminum peeling" that separate from the body layer occur (hereinafter referred to as "blistering phenomenon"), a CRT having a smooth and mirror-reflecting metal reflective film is obtained. I couldn't do that.

In order to prevent the "blistering" phenomenon of the metal reflection film, it is conceivable to reduce the thickness of the undercoat film to a thickness sufficient to fill the unevenness of the phosphor layer. There was a limit to thinning. Further, a method in which the baking treatment time of the undercoat film is extended to generate the volatile gas little by little is also considered. However, this method is not practical because the productivity of the CRT is greatly reduced, and the brightness of the CRT is improved. It is now a plan to obtain a metal reflective film having a balance between smoothness and mirror effect required for the above.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a baking process for an undercoat film after the formation of a metal vapor deposition film without causing the metal vapor deposition film to have a "blistering phenomenon". Accordingly, it is an object of the present invention to provide an emulsion composition for forming a metal back undercoat film, which volatilizes to obtain a CRT with high definition and high brightness.

[0008]

Means for Solving the Problems As a result of intensive studies on the above-mentioned problems, the present inventors have found that the aqueous emulsion polymer (A) as a main component has a specific range of particle size and the aqueous emulsion polymer. By using an emulsion composition containing an aqueous emulsion polymer (B) having a specific minimum film-forming temperature different from the coalescence (A) as an undercoat material, an undercoat film excellent in smoothness can be obtained. Have found the present invention.

That is, the present invention relates to an aqueous emulsion polymer (A)
And the acrylic aqueous emulsion polymer (B) having a higher minimum film forming temperature (MFT) than the polymer (A) has a particle size ratio of 1: 3 to 1:65, and the polymer (A) A) an emulsion composition for forming a CRT metal back undercoat film (hereinafter referred to as an emulsion composition), wherein 0.1 to 10 parts by weight of the polymer (B) is mixed with 100 parts by weight. It is in.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The aqueous emulsion polymer (A) used in the present invention is a main component of the emulsion composition of the present invention, and is an appropriate film necessary for forming a CRT metal back undercoat film (hereinafter, referred to as an undercoat film). Hold the thickness,
Further, it is a component that imparts a balance between the film formability of the emulsion composition of the present invention and the baking property of the undercoat film after the formation of the metal vapor-deposited film. Therefore, the aqueous emulsion polymer (A) is not particularly limited as long as the above performance is satisfied.
For example, (a) an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, (b) an alkyl acrylate having an alkyl group having 1 to 4 carbon atoms, and (c) acrylic acid, methacrylic acid, itaconic acid, and crotonic acid. An aqueous emulsion polymer comprising at least one selected unsaturated carboxylic acid is exemplified.

The aqueous emulsion polymer comprises (a) an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms,
A mixture comprising (b) an alkyl acrylate having an alkyl group having 1 to 4 carbon atoms and (c) at least one unsaturated carboxylic acid selected from acrylic acid, methacrylic acid, itaconic acid and crotonic acid is dropped into water. Then, it can be efficiently obtained by a usual emulsion polymerization method.

The particle size of the aqueous emulsion polymer (A) is not particularly limited as long as a smooth metal reflective film without pinholes can be obtained, but from the viewpoint of compatibility with the aqueous emulsion polymer (B). , 0.05 to 0.2 μm is particularly preferred.

Specific examples of the component (a) include those having 1 to 1 carbon atoms.
There is no particular limitation as long as it is an alkyl methacrylate having an alkyl group of 4, but examples thereof include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, and sec-butyl methacrylate. In view of the strength of methyl methacrylate, methyl methacrylate is particularly preferred. These alkyl methacrylates may be used alone or in combination of two or more.

The component (a) is preferably copolymerized in the range of 35 to 95% by weight in the component (A) from the viewpoint of the film formability of the emulsion composition and the baking property of the obtained undercoat film. And particularly preferably in the range of 45 to 80% by weight. When the content of the component (a) is an aqueous emulsion polymer (A)
When the content is at least 35% by weight, the baking property of the undercoat film is improved, and when the content is 95% by weight or less, the increase in MFT of the obtained aqueous emulsion polymer (A) is hindered, and the practicability is high. An aqueous emulsion polymer (A) having an appropriate MFT can be obtained, and an emulsion composition suitable for a practical line for CRT production can be obtained.

The alkyl acrylate (b) having an alkyl group having 1 to 4 carbon atoms used in the synthesis of the component (A) is an important component in the film formability of the emulsion composition of the present invention. Specific examples of the component (b) are not particularly limited as long as they are alkyl acrylates having an alkyl group having 1 to 4 carbon atoms. For example, methyl acrylate, ethyl acrylate, n-butyl acrylate,
Examples thereof include i-butyl acrylate and sec-butyl acrylate. Among them, ethyl acrylate is particularly preferable for improving the flexibility of the undercoat film. These alkyl acrylates may be used alone or in combination of two or more.

The component (b) is preferably copolymerized with the component (A) in the range of 3 to 60% by weight, particularly 10 to 5%, from the viewpoint of the film-forming properties of the emulsion composition of the present invention.
A range of 0% by weight is preferred. When the content of the component (b) is at least 3% by weight in the component (A), the MFT of the emulsion composition of the present invention does not increase and can be in a favorable range. It tends to be good. Further, by setting the content of the component (b) to 60% by weight or less, an aqueous emulsion polymer (A) having a high practicality and an appropriate MFT can be obtained.
It tends to be able to obtain an emulsion composition that suppresses the decrease in FT and is suitable for a practical line for CRT production.

At least one unsaturated carboxylic acid (c) selected from acrylic acid, methacrylic acid, itaconic acid and crotonic acid used in the synthesis of the component (A) is used to increase the alkalinity of the emulsion composition of the present invention. It is a component that imparts viscosity. Specific examples of the component (c) include acrylic acid, methacrylic acid, itaconic acid, crotonic acid and the like. These may be used alone or in combination of two or more. Of these, methacrylic acid is particularly preferred in that the alkali thickening of the emulsion composition can be appropriately controlled. The component (c) is contained in the component (A) in view of alkali thickening of the undercoat film.
It is preferable to copolymerize in the range of 2 to 12% by weight,
In particular, the range of 3 to 10% by weight is preferable. This is (c)
The content of the component is at least 2 in the aqueous emulsion polymer (A).
By setting the amount by weight, an emulsion composition having an appropriate alkali thickening can be obtained. By setting the amount by weight to 12% by weight or less, the sinterability of the obtained undercoat film is good, and In the baking process, the generation of a firing residue can be prevented.

The emulsion composition of the present invention is characterized in that a small amount of an acrylic aqueous emulsion polymer (B) having a large particle diameter within a specific range is added to the aqueous emulsion polymer (A) in a small amount. It is an essential component for forming a smooth undercoat film, and is a component characteristic of the present invention, because it can solve the problem of “blistering phenomenon”. Specifically, the acrylic aqueous emulsion polymer (B)
Is preferably an aqueous emulsion polymer having a particle size in the range of 0.4 to 5 μm and having a higher MFT than that of the aqueous emulsion polymer (A).

The acrylic aqueous emulsion polymer (B) will be described below.

In order to form a metal reflective film which does not cause a “blistering phenomenon” in a baking treatment step of an undercoat film after forming a metal vapor-deposited film, the present inventors have proposed an acrylic aqueous emulsion polymer (A) The emulsion (A) and the aqueous acrylic emulsion polymer (B) having a higher MFT than the polymer (A) in a particle size ratio of 1: 3 to 1:65. If a suitable amount of pinholes are formed in the metal-deposited film by blending the polymer (B) in an amount of 0.1 to 10 parts by weight, pyrolysis gas generated during baking of the undercoat film is passed through the pinholes. It has been found that it is possible to form a metal reflection film having a smooth mirror effect by volatilization.

The range of the particle size of the acrylic aqueous emulsion polymer (B) used in the present invention is such that when the particle size ratio to the emulsion polymer (A) is small, the pyrolysis gas generated during the baking treatment of the undercoat film is used. If the diameter is too large, the size of the pinhole is too large and the amount of light transmitted through the metal reflection film increases, thereby lowering the brightness of the CRT. When forming a vapor-deposited film, coating unevenness is likely to occur on the vapor-deposited film.
Since it tends to be unsuitable for the practical production line of T, the particle size ratio of the emulsion polymer (A) to the emulsion polymer (B) is 1:
A range of 3 to 1:65 is preferred. Specifically, for example,
When the particle size of the emulsion polymer (A) is in the range of 0.05 to 0.2 μm, the particle size of the emulsion polymer (B) is 0.4
The range of about 5.0 μm is preferable. In this case, the range of 0.6 to 2.0 μm is particularly preferable in order to form a pinhole having an appropriate size that does not cause a further “blistering phenomenon” and does not lower the brightness of the CRT.

Further, the polymer particles in the aqueous emulsion polymer (B) have good dispersion stability in the emulsion composition, and can improve the storage stability of the emulsion composition of the present invention. .

The aqueous emulsion polymer (B) used in the present invention comprises:
Although it is not particularly limited as long as it is an acrylic resin, it is preferable that the component does not have a firing residue in the baking treatment step of the undercoat film and is completely fired. Since the ordinary baking treatment is performed at a temperature of 500 ° C. or lower, it is preferable that the aqueous emulsion polymer (B) contains an acrylic resin which is completely thermally decomposed at a temperature of 500 ° C. or lower as a main component. Specifically, for example, methacrylate monomer, acrylate monomer,
And a homopolymer and / or copolymer of at least one monomer mixture consisting of an acid monomer and an acid monomer. In the present invention, the method for producing the aqueous emulsion polymer (B) is not particularly limited. However, since the aqueous emulsion polymer (B) is used after being mixed with the aqueous emulsion polymer (A), the monomer mixture is dropped into water. In addition, it is preferable to produce by a usual emulsion polymerization method.

The methacrylate monomer includes, for example, methyl methacrylate, ethyl methacrylate,
n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, sec-butyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, etc. Is mentioned. Examples of the acrylate monomer include methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, and 2- acrylate. Ethylhexyl acrylate, 2
-Hydroxyethyl acrylate, 2-hydroxypropyl acrylate, benzyl acrylate and the like. Examples of the acid monomer include methacrylic acid, acrylic acid, and itaconic acid.

The content of the aqueous emulsion polymer (B) is
0.1 to 1 based on 100 parts by weight of the aqueous emulsion polymer (A)
The range of 0 parts by weight is preferable, and the range of 1 to 5 parts by weight is particularly preferable in terms of the balance between the amount of generated pyrolysis gas and the amount of pinholes generated in the baking treatment step of the undercoat film.

By setting the content of the aqueous emulsion polymer (B) to 0.1 parts by weight or more, pinholes can be formed in the metal-deposited film, and aluminum floating during the baking process of the undercoat film can be achieved. The prevention effect is expressed, and there is a tendency that the occurrence of "blistering phenomenon" of the metal reflection film can be suppressed. Also, by using 10 parts by weight or less, an appropriate amount of pinholes can be generated in the metal deposition film. In addition, the amount of transmitted light to the inner surface of the CRT panel is small, and there is a tendency that a metal reflection film having good reflection efficiency can be formed.

As described above, the undercoat material of the present invention can provide a CR if the number and size of pinholes are controlled to specific ranges by the aqueous emulsion polymer (B).
It is possible to easily obtain an undercoat film having high smoothness and good uniformity according to the manufacturing conditions of T.

The aqueous emulsion polymer (B) to be added to the emulsion composition of the present invention needs to have a higher MFT than the aqueous emulsion polymer (A). This is because the aqueous emulsion polymer (B) is scattered in the aqueous emulsion polymer (A) for continuously forming the undercoat film to artificially generate pinholes in the undercoat film. Since it is necessary, the polymer (B) does not dissolve during the filming treatment of the emulsion composition,
In addition, it is necessary to have a property capable of maintaining the shape of the polymer particles without fusing in the undercoat film made of the aqueous emulsion polymer (A) formed into a film.

Specifically, in general, at the time of filming processing for forming an undercoat film on the inner surface of a CRT panel, the emulsion composition is applied to the phosphor surface and then applied to the phosphor screen.
In many cases, drying is performed at a temperature in the range of 50 to 50 ° C.

When the emulsion composition of the present invention is used under the above-mentioned drying conditions, the MFT of the aqueous emulsion polymer (A) must be maintained at 30 to 50 ° C. in order to form a good performance undercoat film. And the MFT of the aqueous emulsion polymer (B) is higher than 50 ° C, more preferably 70 ° C.
The temperature is preferably set to not less than ° C. This is because when the MFT of the aqueous emulsion polymer (B) is higher than 50 ° C., the MFT of the aqueous emulsion polymer (B) is higher than that of the aqueous emulsion polymer (A), and the heat during drying of the undercoat film is high. Only the aqueous emulsion polymer (A) forms a film to form a uniform continuous film, and the polymer particles of the aqueous emulsion polymer (B) are not fused to the resulting undercoat film, This is because they can exist in the form of particles. As described above, by forming a metal vapor-deposited film on the undercoat film in which the polymer particles of the component (B) exist in the form of particles,
The particles generate pinholes in the metal-deposited film, and during the baking treatment of the undercoat film, the pyrolysis gas of the vapor-deposited film can be evaporated from the pinhole. No CRT or the like occurs, and a CRT having good reflection efficiency of transmitted light and good luminance can be obtained.

The metal deposited on the undercoat film used for forming the metal reflection film is not particularly limited, and a known metal such as aluminum can be used.

The emulsion composition of the present invention includes:
Additives conventionally used if necessary, for example, polyvinyl alcohol borate complex, hydrogen peroxide,
Known materials such as colloidal silica and ammonium oxalate may be added.

[0033]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. In addition, the part in an Example shows a weight part, and each physical property value displayed in the Example was evaluated based on the following measuring method.

(1) Minimum film forming temperature (MFT: ° C) An emulsion composition is coated on a metal plate (manufactured by Takabayashi Rika Co., Ltd.) having a continuous temperature gradient and dried to form a uniform crack-free film. Was determined. Here, the metal plate having a continuous temperature gradient is an aluminum plate for thinly casting latex, one of which is connected to a cooling bath, the other is a structure heated by a heater, and The plate is insulated, and after a certain period of time, the temperature gradient reaches an equilibrium. (2) Particle size (μm) The particle size of the polymer particles in the emulsion was measured by a light scattering method using a laser as a light source (DLS-600 Otsuka Electronics Co., Ltd.)
Manufactured). (3) Stability of emulsion composition After the emulsion composition was left in a beaker for 2 days,
The presence or absence of sedimentation of the polymer particles in the composition was visually evaluated. ○: No particle sedimentation ×: Particle sedimentation

(4) Aluminum Floating After the baking process of the undercoat film, the surface of the aluminum vapor-deposited film was visually evaluated. ○: No aluminum floating △: Water bubble-like aluminum floating of 5 mmφ or more partially occurred ×: Aluminum floating occurred on more than half of the phosphor surface (5) Transmitted light amount Metal deposition after forming an undercoat film on the phosphor surface side In order to measure the amount of light transmitted through a metal reflective film formed by forming a film and baking and removing the film, a light is applied from the inner surface of the glass, and the amount of light transmitted through the glass surface is measured using a digital illuminometer (SLX-1332). : Sansho Co., Ltd.). The measurement result is based on the amount of transmitted light of the conventional product Primal B-74 (manufactured by Nippon Acrylic Chemicals, Inc.) (1.0).
As described. The standard of the transmitted light amount is as follows. ) Less pinholes <1.0 (Primal B-74) <Plenty of pinholes

<< Production of Aqueous Emulsion Polymer >><Synthesis Example 1: Synthesis of Emulsion (A)> In a two-neck separable flask, 630 parts of water and sodium lauryl sulfate (trade name: Emar 0, manufactured by Kao Corporation) After charging 8.0 parts and 2.0 parts of potassium persulfate, a mixture consisting of 208 parts of methyl methacrylate, 160 parts of ethyl acrylate and 32 parts of methacrylic acid was added, and the mixture was treated in a nitrogen atmosphere under a nitrogen atmosphere.
Emulsion (A) was obtained by heat polymerization at 0 ° C. for 6 hours.
The particle size of the obtained emulsion is 90 nm, and the MFT is 3
At 7 ° C., the solid content was 38% by weight.

<Synthesis Example 2: Synthesis of emulsion (B)>
In a two-necked separa flask, 740 parts of water and polyoxyethylene nonylphenyl ether (Emulgen 9 manufactured by Kao Corporation)
10, HLB 12.2) 10.0 parts and potassium persulfate 0.5 part were added, and then a mixture was prepared by adding a mixture of 392 parts of methyl methacrylate and 8.0 parts of methacrylic acid. One half of this mixture was added dropwise at 70 ° C. over 2 hours in a nitrogen atmosphere, and the mixture was heated for 1 hour to carry out heat polymerization. Next, these particles were used as seed particles, and a half amount of the remaining mixture was dropped in a nitrogen atmosphere at 70 ° C. over 2 hours, and held for 1 hour to perform seed polymerization to prepare the emulsion (B). Obtained. The particle size of the obtained emulsion (B) was 900 nm, the MFT was 100 ° C., and the solid content was 35% by weight.

<Synthesis Example 3: Synthesis of emulsion (C)>
Polymerization is carried out in the same manner as in Synthesis Example 2 except that the emulsifier is changed to 10.0 parts of polyoxyethylene nonylphenyl ether (Emulgen 930, HLB 15.1 manufactured by Kao Corporation) having a higher HLB value than Synthesis Example 2. Was carried out to obtain an emulsion (C). The particle size of the obtained emulsion is 200
nm, MFT was 100 ° C., and solid content was 35% by weight.

<Synthesis Example 4: Synthesis of emulsion (D)>
The monomer mixture prepared in the same manner as in Synthesis Example 2 was equally divided into seven parts, and as a first-stage polymerization, a 1/7 amount of the monomer mixture was dropped into a heated flask over 30 minutes. Heat polymerization was carried out for 30 minutes. Next, using these particles as seed particles, a 1/7 amount of the monomer mixture in the second stage was added dropwise over 30 minutes, and held for 30 minutes to carry out heat polymerization. In the same manner, in the same manner, the dropping / holding is repeated in the order of the third stage, the fourth stage, the fifth stage, the sixth stage, and the seventh stage over a period of 30 minutes, followed by holding for 1 hour to perform seed polymerization. Except for performing polymerization, polymerization was performed in the same manner as in Synthesis Example 2,
Emulsion (E) was obtained. The particle size of the obtained emulsion is 6 μm, MFT is 100 ° C., and solid content is 35% by weight.
Met.

<< Formation of Metal Reflective Film >><Example1> An emulsion in which the mixing ratio of (A) / (B) was 100/1 (weight ratio) was obtained from the emulsions obtained in Synthesis Examples 1 and 2. A composition was prepared. So that the solid content of this emulsion composition is 17.0% by weight,
0.5% by weight of poval borate complex and 0.5% by weight of hydrogen peroxide were added as additives, and 82% by weight of water was added as a diluent to prepare an undercoat liquid for forming a metal reflection film.
This preparation was applied on a phosphor layer of a 14-inch cathode ray tube preheated to 42 ° C. by a spin coating method, and heated and dried with a far-infrared heater to form an undercoat film. Aluminum was deposited. Then, in an air atmosphere, the temperature was raised to 450 ° C. at a rate of 7 ° C./min, and the temperature was maintained for 30 minutes, and then a baking treatment of the undercoat film was performed. The thus obtained metal reflection film was uniformly formed without aluminum floating and aluminum peeling.

<Example 2> The emulsions obtained in Synthesis Example 1 and Synthesis Example 2 were mixed with each other at a mixing ratio of (A) / (B) of 100.
/ 4 (weight ratio) emulsion composition was prepared.
Using this emulsion composition, an undercoat liquid for forming a metal reflective film was prepared in the same manner as in Example 1, and the undercoat film was baked. The thus obtained metal reflection film was uniformly formed without aluminum floating and aluminum peeling.

Example 3 The emulsions obtained in Synthesis Examples 1 and 2 were mixed with each other at a mixing ratio of (A) / (B) of 100.
/ 8 (weight ratio) was prepared.
Using this emulsion composition, an undercoat liquid for forming a metal reflective film was prepared in the same manner as in Example 1, and the undercoat film was baked. The thus obtained metal reflection film was uniformly formed without aluminum floating and aluminum peeling.

Example 4 The emulsions obtained in Synthesis Examples 1 and 2 were mixed with each other at a mixing ratio of (A) / (B) of 100.
/0.4 (weight ratio) was prepared. Using this emulsion composition, an undercoat liquid for forming a metal reflective film was prepared in the same manner as in Example 1, and the undercoat film was baked. In the metal reflection film thus obtained, aluminum was partially floated, aluminum was peeled off, and a uniform metal reflection film could not be obtained.

Comparative Example 1 An undercoat liquid for forming a metal reflective film was prepared in the same manner as in Example 1 except that Primal B-74 manufactured by Nippon Acrylic Chemical Co., Ltd. was used as the emulsion. The coating was baked. Aluminum floating and aluminum peeling occurred in the metal reflection film thus obtained, and a uniform metal reflection film could not be obtained.

<Comparative Example 2> As the emulsion, except that the emulsion (A) shown in Synthesis Example 1 was used alone,
An undercoat liquid for forming a metal reflective film was prepared in the same manner as in Example 1, and a baking treatment of the undercoat film was performed. In the metal reflection film thus obtained, aluminum floating and aluminum peeling occurred, and a uniform metal reflection film could not be obtained.

Comparative Example 3 The emulsions obtained in Synthesis Example 1 and Synthesis Example 2 were mixed with each other at a mixing ratio of (A) / (B) of 100.
/ 12 (weight ratio) was prepared. Using this emulsion composition, an undercoat liquid for forming a metal reflective film was prepared in the same manner as in Example 1, and the undercoat film was baked. The metal reflection film thus obtained did not float or peel off aluminum, but had too many pinholes in the metal reflection film, resulting in a large amount of transmitted light and low reflection efficiency.

Comparative Example 4 The emulsions obtained in Synthetic Examples 1 and 3 were mixed with (A) / (C) at a mixing ratio of 10
An emulsion composition of 0/1 (weight ratio) was prepared. Using this emulsion composition, an undercoat liquid for forming a metal reflective film was prepared in the same manner as in Example 1, and the undercoat film was baked. The metal reflection film thus obtained floated and peeled off aluminum, and a uniform metal reflection film could not be obtained.

<Comparative Example 5> The emulsions obtained in Synthesis Examples 1 and 4 were mixed with each other at a mixing ratio of (A) / (D) of 100.
/ 1 (weight ratio) was prepared.
Using this emulsion composition, an undercoat liquid for forming a metal reflective film was prepared in the same manner as in Example 1, and the undercoat film was baked. In the metal reflection film thus obtained, aluminum did not float and aluminum did not peel, but pinholes formed in the metal reflection film became large, the amount of transmitted light increased, and the reflection efficiency decreased.

[0049]

[Table 1]

The symbols in the table are as follows. MMA: Methyl methacrylate EA: Ethyl acrylate MAA: Methacrylic acid BA: Butyl acrylate

[0051]

[Table 2]

[0052]

As described above, the emulsion composition for a CRT metal back undercoat film according to the present invention comprises:
It is possible to effectively prevent a "blistering phenomenon" such as aluminum floating and aluminum peeling, and to obtain a CRT having a metal reflective film that maintains a high reflectance.

Claims (4)

[Claims] 1. A particle size ratio of an aqueous emulsion polymer (A) to an acrylic aqueous emulsion polymer (B) having a minimum film formation temperature (MFT) higher than that of the polymer (A) is 1: 3 to 1:
65. An emulsion composition for forming a CRT metal back undercoat film, wherein 0.1 to 10 parts by weight of the polymer (B) is mixed with 100 parts by weight of the polymer (A). Stuff. 2. The aqueous emulsion polymer (A) has 1 to 4 carbon atoms.
Alkyl methacrylate (a) having an alkyl group of
An aqueous emulsion polymer (B) comprising an alkyl acrylate (b) having an alkyl group having 1 to 4 carbon atoms, at least one unsaturated carboxylic acid (c) selected from acrylic acid, methacrylic acid, itaconic acid and crotonic acid. 2. The emulsion composition for forming a CRT metal back undercoat film according to claim 1, wherein the particle size of (1) is in the range of 0.4 to 5 [mu] m. 3. The minimum film formation temperature (MFT) of the aqueous emulsion polymer (A) is in the range of 30 to 50 ° C., and the minimum film formation temperature (MFT) of the aqueous emulsion polymer (B) is higher than 50 ° C. The emulsion composition for forming a CRT metal back undercoat film according to claim 1 or 2, characterized in that: 4. The aqueous emulsion polymer (A) has 1 to 4 carbon atoms.
Examples of the alkyl methacrylate (a) include at least one methacrylate selected from methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, and sec-butyl methacrylate, and an alkyl acrylate having an alkyl group having 1 to 4 carbon atoms ( It is characterized in that at least one acrylate selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, i-butyl acrylate and sec-butyl acrylate is used as b), and methacrylic acid is used as the unsaturated carboxylic acid (c). The emulsion composition for forming a CRT metal back undercoat film according to any one of claims 1 to 3. [0001]