JPH04116558A - Photosensitive phosphor paste composition - Google Patents

Abstract

PURPOSE:To allow development by using water at the time of patterning of a film by forming a photopolymerizable initiator of 2-benzyl-2- dimethylamino-1-(4-morpholinophenyl)-butane-1-on. CONSTITUTION:The photopolymn. initiator of the photosensitive phosphor paste compsn. formed by kneading an org. high-polymer binder, a photopolymerizable monomer, the photopolymn. initiator, phosphor poder, and an org. solvent is formed of the 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butane-1-on. The development by using water is possible in this way at the time of patterning the film capable of forming the fine patterns which are heretofore not obtainable with the conventional photosensitive phosphor paste compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photosensitive phosphor paste composition in a fluorescent display device.

[Conventional technology]

Conventionally, in order to form a patterned phosphor in a fluorescent display device, a phosphor powder and an organic polymer conjugate are dissolved and dispersed in a solvent to form a phosphor paste, and this is applied onto a desired substrate. By patterning by screen printing, drying, and firing, the organic polymer bond was thermally decomposed and removed, and a phosphor was formed in which the phosphor powder was patterned and fired.

Recently, as in other fields, there has been a demand for finer phosphor patterns in fluorescent display devices, and to meet this demand, photosensitive phosphor pastes have been developed. was expected to appear.

Therefore, there is a method of forming the phosphor with high precision by using both a printing method and an exposure method (Japanese Patent Laid-Open No. 51-32
No. 271), a method using a suspension of photoresist mixed with a phosphor (Japanese Patent Laid-Open No. 52-48465), and a method using a paste obtained by kneading a negative photosensitive resin and a phosphor. (Japanese Unexamined Patent Publication No. 178946/1982) and a method of patterning by adding an ethylenically unsaturated compound to a phosphor paste (Japanese Unexamined Patent Publication No. 2-99585)
No. 1 specification) etc. have been proposed.

In these conventional techniques, even if it is possible to impart photosensitivity, since a phosphor powder is blended, a white phosphor would be fine, but (Zn, Cd)S: Ag
When a red phosphor powder such as phosphor powder is added to a photosensitive resin, it inhibits the transmission of ultraviolet rays, and the ultraviolet rays cannot efficiently penetrate to the bottom, resulting in extremely low sensitivity of the photosensitive resin. Therefore, the film thickness of the phosphor after patterning and baking cannot be greater than 10.14 m, and the resulting phosphor does not have sufficient brightness, resulting in a cloudy phosphor with poor light-emitting properties. There was a problem.

Furthermore, when a phosphor paste is applied to a substrate to form a film, if water is used as a solvent for the paste, the drying speed is fast and the shape of the resulting film is poor. Therefore, it is desirable to select and use water that has a slow evaporation rate.

When such a photosensitive phosphor paste is used, an organic solvent is inevitably used as a developer for patterning, but the use of an organic solvent as a developer is not preferable from the viewpoint of the working environment. Further, when a phosphor paste using water is applied to a substrate by a screen printing method, there is a problem that the paste tends to generate bubbles and clog the screen.

[Problem that the invention seeks to solve]

The present invention improves this situation, namely, the problem that conventional phosphor pastes cannot obtain sufficient luminescent properties because a thick film cannot be obtained, and therefore sufficient luminescent properties cannot be obtained. It is an object of the present invention to provide a photosensitive phosphor paste composition in which a uniform phosphor coating is formed using a phosphor paste using an organic solvent, and the coating can be developed using water when patterning the phosphor paste. This was done for a purpose.

[Means to solve the problem]

As a result of extensive research to achieve the above object, the present inventors discovered that the object could be achieved by using a specific compound as a photopolymerization initiator, and based on this knowledge, the present invention was developed. It was completed.

That is, the present invention provides a photosensitive phosphor paste composition prepared by kneading an organic polymer binder, a photopolymerizable monomer, a photoinitiator, a phosphor powder, and an organic solvent, in which the photopolymerization initiator is 2
A photosensitive phosphor paste composition characterized in that it is -benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one.

The present invention will be explained in detail below.

When the composition of the present invention is formed into a film in order to make the composition of the present invention water-developable, the organic polymer binder used in the composition of the present invention must be selected to be soluble or easily dispersible in water. There is. As such materials, those used in conventional phosphor paste compositions can be used. For example, methylcellulose, hydroxymethylcellulose,
Homopolymers of celluloses such as hydroxyethylcellulose, hydroxypropylcellulose, and hydroxyglobil methylcellulose and monomers such as acryloylmorpholine, acrylamide, and dimethylacrylamide, and copolymers of these monomers with acrylic acid, methacrylic acid, etc. , specifically polyacryloylmorpholine, acryloylmorpholine/β-hydroxyethyl acrylate copolymer, acryloylmorpholine/β-hydroxyglobyl acrylate copolymer, polyacrylamide, polydimethylacrylamide, methylacrylamide/acrylic acid copolymer. There are acrylic polymers such as polymers, and one or more of these may be selectively mixed and used.

In particular, hydroxypropylcellulose is excellent in terms of solubility in solvents and developability. The molecular weight of these organic polymer conjugates is preferably in the range of 10,000 to 2.000.000, preferably 30.000 to 100,000; if it is less than 10.000, the adhesion to the substrate will decrease; Moreover, if it exceeds 2,000.000, it is not preferable because it becomes difficult to thermally decompose and remove the organic polymer bond during firing.

Examples of photopolymerizable monomers include polyethylene glycols such as diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, tetraethylene glycol diacrylate, and tetraethylene glycol dimethacrylate, polypropylene glycol, etc. Diacrylates or dimethacrylates of polyalkylene glycols, pentaerythritol
Tol triacrylate, pentaerythritol trimethacrylate, pentaerythritol diacrylate,
Examples include pentaerythritol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 2,2-dimethylpropane diacrylate, and 2,2-dimethylpropane dimethacrylate. One or more of these may be selected and used in combination.

As a photopolymerization initiator, 2-benzyl-2-dimethylamino-1-(4-morpholino-7enyl)-butane-1-
In addition to using at least 50% by weight of
゜Benzophenones such as 4-bis(dimethylamino)benzophenone, benzoin ethers such as inbutylbenzoin ether, inpropylbenzoin ether, benzoin ethyl ether, benzoin methyl ether, 2,4-diethylthioxanthone, 2-chlorothioxanthone, etc. Thioxanthone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 1,1-dichloroacetophenone, etc. can be used in combination. These can be used alone or in combination of two or more.

Examples of the fluorescent powder include (Zn, Cd)S:
In addition to colored ones such as Ag, ZnO: Zn, Z
nS: Cu, At, ZnS: Ag, Y,
O□S: Eu, ZnS: Zn, (Y, Cd
) BO, : Eu, Zn25in, : Mn, B
A conventionally known material such as aMgAtttOz3:Eu can be used.

Examples of organic solvents include diethylene glycol monoethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether 1, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether, and propylene glycol monobutyl ether. , dipropylene glycol, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether,
diethylene glycol monomethyl ether acetate,
Examples include 3-methyl-3-methoxybutanol, methoxybutyl acetate, and terpineol. These can be used alone or in combination of two or more. Among these organic solvents, 3-methyl-3-
Mention may be made of methoxybutanol. When a solvent with a fast evaporation rate, such as water, is used instead of these organic solvents, the drying speed is fast, so the screen mesh marks will be uneven on the surface of the applied photosensitive phosphor paste layer. It is preferable to select and use an organic solvent with a slow evaporation rate to prevent the solvent from remaining on the screen or clogging the screen mesh.

Therefore, it is desirable that the organic solvent used in the composition of the present invention has a specific evaporation rate of 25 or less when the amount of butyl acetate evaporated per unit time is 100.

The proportion of the photopolymerizable monomer in the composition of the present invention is 30 to 200 parts by weight, preferably 30 to 120 parts by weight, per 100 parts by weight of the organic polymer binder, and the photopolymerization initiator is added to the entire composition. 0.01 to 25 parts by weight, more preferably 0.1
It is necessary to use ~15 parts by weight. The organic solvent is 250 to 700 parts by weight, preferably 300 to 500 parts by weight, per 100 parts by weight of the organic polymer conjugate, and the phosphor powder is used for the organic polymer conjugate, photopolymerizable monomer, and photopolymerization initiator The amount is 50 to 200 parts by weight, preferably 100 to 150 parts by weight, based on 100 parts by weight of the total amount of agent and organic solvent.

If the photopolymerizable monomer is less than 30 parts by weight, photocuring will be insufficient, and the image area will dissolve during development, making it impossible to form an image.
Furthermore, the light emitting characteristics are deteriorated.

If it exceeds 200 parts by weight, the resolution of fine images will decrease,
This is not preferable because it tends to cause sticking.

If the amount of the photopolymerization initiator is less than 0.01 part by weight, photocuring at a normal exposure amount will be insufficient, and the image will dissolve during development, making it impossible to form an image. Furthermore, since the photopolymerization initiator has low solubility in a solvent, if it is used in an amount exceeding 25 parts by weight, the photopolymerization initiator will be unevenly dispersed when the composition is formed into a film, making it impossible to form a fine image. Not only that, but it also reduces the light transmittance, which is undesirable. Said 2-benzyl-2-dimethylamino-1-(4-
The object of the present invention cannot be achieved unless morpholinophenyl)-butan-1-one is used in an amount of at least 50% by weight as a photopolymerization initiator.

If the amount of the phosphor layer is less than 50 parts by weight, sufficient light emitting properties cannot be obtained, and sufficient strength cannot be maintained when fired. If the amount exceeds 200 parts by weight, UV absorption by the phosphor becomes too large and the action of the photopolymerization initiator is inhibited, resulting in image dissolution during development, making it impossible to form an image.

If the organic solvent is less than 250 parts by weight, the viscosity of the photosensitive phosphor paste composition when prepared is too high to form a phosphor film. If it exceeds 700 parts by weight, the viscosity becomes too low and the phosphor in the photosensitive phosphor paste composition will sediment and separate, which is not preferable.

The viscosity of the photosensitive phosphor paste composition prepared by kneading these components is 50 to 50 at 25°C.
It is preferably in the range of 4,000 p, especially in the range of 200 to 2,000 p. If it is less than 50p, the phosphor in the photosensitive phosphor paste composition will sediment and separate, which is undesirable, and if it exceeds 4,000p, the viscosity will be too high to form a film.

The composition of the present invention further includes hydroquinone, if necessary.
A thermal polymerization inhibitor such as t-butylhydroquinone, benzoquinone, or catechol, a dye for visualization, a pigment, and an antifoaming agent may also be added.

Next, to give an example of how to use the composition of the present invention, first, the photosensitive phosphor paste composition of the present invention adjusted to an appropriate viscosity is coated on the entire surface of a glass substrate using a screen printing method to form a dried film. Apply to a thickness of ~60 μm, and apply 75 μm.
Dry for 15-20 minutes in an atmosphere of ~80°C. Next, active light such as ultraviolet light is selectively irradiated through a mask having a desired number of turns. For example, an ultra-high pressure mercury lamp irradiates in a range of 10 to 200 mJ/i. Subsequently, by applying a developer such as water, only the portions that were not irradiated with actinic rays are selectively removed. At this time, methods for applying the developer include a spray method, a dipping method, and the like. Once the development is completed, the film is dried using a dryer, etc., and fired at elevated temperature in a firing oven. The firing temperature at this time varies depending on the type of phosphor layer used, but the approximate maximum temperature is approximately 500 to 550°C. The thickness of the phosphor layer obtained by firing is about 10 to 40 μm.

〔Example〕

EXAMPLES Next, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the Examples.

Example 1 Phosphor layer 51 made of (Zn, Cd)S:Ag
0 parts by weight, 10 weight of hydroxypropyl cellulose with an average molecular weight of 60,000! , 100 parts by weight of pentaerythritol triacrylate, 10 parts by weight of 2-benzyl-2-dimethylamine-1-(4-morpholinophenyl)-butan-1-one, 0.5 parts by weight of methylhydroquinone, 3-methyl-3- A photosensitive phosphor paste composition was prepared by kneading 300 parts by weight of methoxybutanol in a three-roll mill. The viscosity of this composition was measured using a B-type rotational viscometer.
It was 1,200p at 5°C.

Next, this photosensitive phosphor paste composition was applied to the entire surface of a glass substrate for a fluorescent display tube through a 150 mesh screen, left for 10 minutes, dried at 80°C for 20 minutes, and allowed to cool to room temperature. I left it alone.・Then, a 3KW ultra-high-pressure mercury lamp was used to pass through a mask with a predetermined pattern.
After selectively irradiating with ultraviolet rays of 00 mJ/- and developing with water for 1 minute, this was baked at 500 DEG C. for 10 minutes to form a 20 μm thick phosphor layer having a dot pattern of 80 μm square. When the thus obtained phosphor layer was used as a fluorescent display tube and its luminescent properties were investigated, good red luminescence was obtained without any discoloration.

Example 2 Phosphor layer 510 made of (Zn, Cd)S:Ag
Parts by weight, 100 parts by weight of ciprovir cellulose in water with an average molecular weight of 60,000, 100 parts by weight of pentaerythritol triacrylate, 7 parts by weight of 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 3 parts by weight of 2,4-diethylthioxanthone, 0.5 parts by weight of methylhydroquinone, 3-methyl-3-
A photosensitive phosphor paste composition was prepared by kneading 300 parts by weight of methoxybutanol in a three-roll mill.

The viscosity of this composition was 25° as measured with a BW rotational viscometer.
It was 1,200p at ℃.

Next, a phosphor layer was formed in the same manner as in Example 1, and the luminescent properties were examined using this as a fluorescent display tube, and the same results as in Example 1 were obtained.

2-Benzyl-2-dimethylamino- in Comparative Example Example 1
2-methyl-(4-(methylthio)phenyl) instead of 1-(4-morpholinophenyl)-butan-1-one
A photosensitive phosphor paste composition consisting of the same composition except that -2-morpholinopropan-1-one was used and was attempted to be patterned in the same manner as in Example 1, but the phosphor was removed during development. The phosphor layer could not be formed because the entire phosphor layer was washed away.

〔Effect of the invention〕

Because the photosensitive phosphor paste composition of the present invention uses a specific compound as a photopolymerization initiator, it is possible to form a fine pattern that cannot be obtained with conventional photosensitive phosphor paste compositions. , which can be effectively used in the field of phosphor manufacturing.

Claims (1)

[Claims] (1) In a photosensitive phosphor paste composition formed by kneading an organic polymer binder, a photopolymerizable monomer, a photoinitiator, a phosphor powder, and an organic solvent, the photopolymerizable initiator contains 2 A photosensitive phosphor paste composition characterized in that it is -benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one.