JP2003292947A - Fluorescent paste - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide fluorescent paste in which fluorescent substance having a large BET specific surface area is sufficiently dispersed. <P>SOLUTION: The fluorescent paste comprises a nonionic surfactant bearing a hydroxyalkyl group and a nitrogen atom, a fluorescent substance of a BET specific surface area of ≥1 m<SP>2</SP>/g, a binder and a solvent. In the fluorescent paste, the nonionic surfactant is at least one selected from the group consisting of chemical compounds represented by the following formulas: RN(R'-OH)<SB>2</SB>, RNH(R'-OH), RCON(R'-OH)<SB>2</SB>, RCONH(R'-OH), RN(R'-OH)R"N(R'-OH)<SB>2</SB>, RNHR" N(R'-OH)<SB>2</SB>(wherein R is a 8-18C alkyl or alkenyl; R' and R" are each 1-4C alkylene). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor paste, and more particularly to a phosphor paste used for forming a layer of a phosphor used in a plasma display (PDP) which is a vacuum ultraviolet ray excited light emitting device, a rare gas lamp and the like. .

[0002]

2. Description of the Related Art In recent years, as the demand for higher brightness of PDPs has increased, B has been improved in order to improve the brightness of the light emission of the phosphor layer.
Phosphors having a large ET specific surface area and a small particle size have been developed and manufactured. However, when the BET specific surface area of the phosphor becomes larger than 1 m ² / g,
When the phosphor is mixed with a binder, a solvent and a dispersant to form a phosphor paste, the dispersion becomes insufficient, and there is a problem that it becomes difficult to apply the phosphor paste to the substrate by a screen printing method or the like.

As a phosphor paste having improved dispersibility, a conventional BaMgAl ₁₀ O ₁₇ : Eu phosphor powder is used.
, A mixture of diethylene glycol monobutyl ether and diethylene glycol monobutyl ether acetate as a solvent, ethyl cellulose as a binder resin, and a phosphoric acid ester surfactant as a surfactant (see, for example, Patent Document 1). Has been proposed in the past. However, it was insufficient to disperse the phosphor having a BET specific surface area of 1 m ² / g or more.

[0004]

[Patent Document 1] Japanese Patent Laid-Open No. 2001-262136

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to provide BE
It is to provide a phosphor paste in which a phosphor having a large T specific surface area is sufficiently dispersed.

[0006]

Under the circumstances, the inventors of the present invention have conducted intensive studies on phosphor pastes to solve the above-mentioned problems, and as a result, have found that a non-compound composed of a compound containing a hydroxyalkyl group and a nitrogen atom is used. The inventors have found that a phosphor paste containing an ionic surfactant has good dispersibility of the phosphor and is easy to apply, and completed the present invention.

That is, the present invention provides a phosphor paste containing a nonionic surfactant composed of a compound containing a hydroxyalkyl group and a nitrogen atom, a phosphor having a BET specific surface area of 1 m ² / g or more, a binder and a solvent. I will provide a. Further, the present invention provides that the nonionic surfactant is RN
(R'-OH) ₂ , RNH (R'-OH), RCON
(R'-OH) ₂ , RCONH (R'-OH), RN
(R'-OH) R''N (R'-OH) ₂ , RNH
R ″ N (R′—OH) ₂ (where R is an alkyl or alkenyl group having 8 to 18 carbon atoms, R ′, R ″
Is an alkylene group having 1 to 4 carbon atoms. And a phosphor paste as described above, which is one or more selected from the group consisting of compounds represented by Further, the present invention provides a VUV-excited light emitting device using a phosphor layer obtained by applying any one of the phosphor pastes described above onto a substrate and heating.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below.
Explain. Fluorescence contained in the phosphor paste of the present invention
As a body, BET specific surface area is 1m ²/ G or more phosphor
To use. BET specific surface area is 1m²/ G less than phosphor
As a result, the problem of dispersion, which is a problem to be solved by the present invention, has occurred.
The larger the BET specific surface area that does not occur, the phosphor particles
Is difficult to disperse in the solvent, the effect of the surfactant is
The BET specific surface area of the phosphor becomes 2m²/ G or more
Great effect at 3m²/ G or more is more effective.

The composition of the phosphor contained in the phosphor paste of the present invention is as a red phosphor Y ₂ O ₃ : Eu,
_{Y 2 O 2 S: Eu,} YBO 3: Eu, (Y, Gd) BO 3:
Eu, GdBO ₃ : Eu, Y ₂ SiO ₅ : Eu, Y ₃ Al ₅ O
_{12: Eu, ScBO 3: Eu} , LuBO 3: Eu , and examples of the green phosphor Zn ₂ SiO _4: Mn, Ba
Al ₁₂ O ₁₉ : Mn, BaMgAl ₁₀ O ₁₇ : Mn, BaM
gAl ₁₀ O ₁₇ : Mn, Eu, BaMgAl ₁₄ O ₂₃ : M
n, CaAl ₁₂ O ₁₉ : Mn, SrAl ₁₂ O ₁₉ : Mn, Y
BO ₃ : Tb, LuBO ₃ : Tb, GdBO ₃ : Tb, S
cBO ₃ : Tb, Sr ₄ Si ₃ O ₈ C 1 ₄ : Eu and the like, and the blue phosphor is BaMgAl ₁₀ O ₁₇ : Eu, B.
aMgAl ₁₄ O ₂₃ : Eu, Y ₂ SiO ₅ : Ce, CaWO
₄ : Pb, (Ca, Sr) MgSi ₂ O ₆ : Eu, (C
a, Sr) Mg ₂ Si ₂ O ₇ : Eu, (Ca, Sr) ₂ Mg
Si ₂ O _7: Eu and the like.

The surfactant contained in the phosphor paste of the present invention is a nonionic surfactant composed of a compound containing a hydroxyalkyl group and a nitrogen atom, and has a hydrophilic part and a lipophilic part in the molecule. The portion containing a hydroxyalkyl group and the portion containing a nitrogen atom of the molecule of the surfactant used in the phosphor paste of the present invention have a high electronegativity and act as a hydrophilic portion. The nitrogen atom-containing portion of the nonionic surfactant comprising a compound containing a hydroxyalkyl group and a nitrogen atom used in the present invention is specifically a functional group such as an amino group, a hydroxyamino group and a cyano group; an amide bond And those having at least one bond such as an imide bond, a urethane bond, an azo bond and a diazo bond.

The lipophilic part is preferably composed of a hydrocarbon group having 8 to 18 carbon atoms. The hydrocarbon group may be a saturated or unsaturated aliphatic hydrocarbon (straight chain, branched chain, cyclic) or an aromatic hydrocarbon.

Examples of the saturated linear hydrocarbon group include octyl group, nonyl group, decyl group, undecyl group, dodecyl group,
Examples thereof include tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group and octadecyl group.

As the saturated branched hydrocarbon group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group,
Dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group having a methyl group bonded as a side chain, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group Group, tetradecyl group, pentadecyl group, one in which an ethyl group is bonded to a hexadecyl group as a side chain, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group,
Tridecyl group, tetradecyl group, pentadecyl group with n-
Examples thereof include those having a propyl group bonded as a side chain.

As the saturated cyclic hydrocarbon group, 4-octylcyclohexyl group, 4-nonylcyclohexyl group, 4
-Decylcyclohexyl group, cyclohexyloctyl group, cyclohexylnonyl group, cyclohexyldecyl group and the like.

Examples of the unsaturated hydrocarbon group include alkenyl groups, alkadienyl groups and alkynyl groups having 8 to 18 carbon atoms. Examples of the aromatic hydrocarbon group include an alkylphenyl group having 8 to 18 carbon atoms and an alkylnaphthyl group.

Amino alcohols and fatty acid alkanolamides are preferable as the nonionic surfactant contained in the phosphor paste of the present invention and composed of a compound containing a hydroxyalkyl group and a nitrogen atom.
(R'-OH) ₂ , RNH (R'-OH), RCON
(R'-OH) ₂ , RCONH (R'-OH), RN
(R'-OH) R''N (R'-OH) ₂ , RNH
R ″ N (R′—OH) ₂ (where R is an alkyl or alkenyl group having 8 to 18 carbon atoms, R ′, R ″
Is an alkylene group having 1 to 4 carbon atoms. The compound represented by () is more preferable because it has a high effect of dispersing the phosphor.

R is an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group; CH ₃ (CH ₂ ) ₇ CH═CH
_{(CH 2) 7 CH 2 -} , CH 3 (CH 2) 7 CH = CH (CH
₂ ) _7-, etc. R'is a methylene group,
Ethylene group, n-propylene group, isopropylene group, n
-Butylene group, isobutylene group, sec-butylene group,
A tert-butylene group may be mentioned. Most preferably,
Bis (2-) represented by RN (CH ₂ CH ₂ OH) ₂ (R is an alkyl or alkenyl group having 8 to 18 carbon atoms)
Hydroxyethyl) alkylamine.

As such a surfactant, for example,
Esomin series (trade name) manufactured by Lion Akzo,
Examples include Esomede (trade name) and Esso Duomin series (trade name).

The nonionic surfactant consisting of a compound containing a hydroxyalkyl group and a nitrogen atom can be used not only as one type but also as a mixture of two or more types. The second type of surfactant includes nitrogen atoms and /
Alternatively, a nonionic surfactant containing no hydroxyalkyl group can be used.

The amount of the nonionic surfactant (total amount when two or more kinds are used) is preferably 0.001 to 20 parts by weight, more preferably 0.1 to 8 parts by weight, relative to 100 parts by weight of the phosphor. Parts by weight, more preferably 0.5 to 5 parts by weight. The effect of the surfactant is greater as the phosphor content in the paste is higher.

The phosphor paste of the present invention contains a binder resin. The binder resin is a polymer that is easily decomposed by heat and is dissolved in a solvent and has a high viscosity. Cellulose resins (ethyl cellulose, methyl cellulose, nitrocellulose, acetyl cellulose, cellulose propionate, hydroxy) that are commonly used are used. Propyl cellulose, butyl cellulose, benzyl cellulose, modified cellulose, etc., acrylic resin (acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-) Butyl acrylate, n-butyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, 2-hydroxy Ethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, benzyl acrylate, benzyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, isobornyl acrylate, isobornyl methacrylate, glycidyl methacrylate, styrene, Polymers comprising at least one of monomers such as α-methylstyrene, 3-methylstyrene, 4-methylstyrene, acrylamide, methacrylamide, acrylonitrile, and methacrylonitrile), ethylene-vinyl acetate copolymer resin, polyvinyl butyral , Polyvinyl alcohol, propylene glycol, urethane resin, melamine resin, phenol resin, alkyd Resin etc. are mentioned.

As the binder resin, not only one kind of the above resins but also two or more kinds can be used. When the work of adding the binder resin is performed, the binder resin can be added in the solid state or the solution state.

The solvent contained in the phosphor paste of the present invention is water and / or an organic solvent. The solvent is preferably one having a high boiling point, which can dissolve the dispersant and the binder resin. Organic solvents that are usually used have a high boiling point among monohydric alcohols; polyhydric alcohols such as diols and triols represented by ethylene glycol and glycerin; compounds obtained by etherifying and / or esterifying alcohols (ethylene glycol mono Alkyl ether, ethylene glycol dialkyl ether, ethylene glycol alkyl ether acetate, diethylene glycol monoalkyl ether acetate, diethylene glycol dialkyl ether, propylene glycol monoalkyl ether, propylene glycol dialkyl ether, propylene glycol alkyl ether acetate) and the like. More specifically, terpineol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, ethylene glycol dipropyl ether, diethylene glycol dibutyl ether, methyl cellosolve acetate. ,
Ethyl cellosolve acetate, propyl cellosolve acetate, butyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2,2,4-
Trimethyl-1,3-pentanediol monoisobutyrate and the like, 2,2,4-trimethyl-1,3
-Pentanediol monoisobutyrate was easier to handle compared to other solvents.

The optimum blending amount of the solvent and the binder varies depending on the phosphor content in the paste (in the range of 5% by weight to 95% by weight) and the desired viscosity. Typically,
When the phosphor content in the paste is low, the binder content is increased, and when the phosphor content is high, the binder content is decreased to obtain a paste having a predetermined viscosity.

The phosphor paste of the present invention contains various components such as a nonionic surfactant containing a hydroxyalkyl group and a nitrogen atom, a phosphor powder, a binder resin and a solvent so as to have a predetermined composition, It can be produced by dispersing and mixing. Examples of dispersion and mixing methods include ultrasonic dispersion, ball mill dispersion, three-roll mill, bead mill, and other industrially commonly used methods. As a pretreatment, pre-mixing may be performed by hand kneading, a planetary rotary kneader, or the like. In addition, in these devices, it is desirable that the portion that comes into contact with the paste composition is ceramic-coated.

The preferred viscosity of the phosphor paste of the present invention is 2500 mPa · s (2500 c) at 25 ° C.
p) to 500,000 mPa · s (500,000 cp)
Range of 3000 mPa · s (3000 cp) to 15
The range of 0000 mPa · s (150,000 cp) is preferable, and more preferably 3500 mPa · s (3500).
cp) to 100,000 mPa · s (100,000 c
The range is p).

In addition to this, a thixotropy-imparting agent, a leveling agent, a plasticizer, a photosensitive material and the like may be added.

The phosphor paste of the present invention is applied on the substrate by a known method such as screen printing, bar coater, roll coater, die coater, ink jet, etc. to form a coating film, and the phosphor layer is heated to form a coating film. Can be formed.

After the coating film of the phosphor paste of the present invention is dried,
By heating at a temperature of 350 ° C. or higher, the binder resin, the nonionic surfactant, and the solvent are removed, and the phosphor layer can be formed. This phosphor layer emits light when excited by ultraviolet rays or vacuum ultraviolet rays.
Although it can be used for a vacuum ultraviolet ray excited light emitting element such as a DP or a mercury-free lamp, it is particularly preferable when used for a vacuum ultraviolet ray excited light emitting element because high brightness can be obtained.

Here, a PDP will be described as an example of a VUV-excited light-emitting display device using the phosphor paste of the present invention, and its manufacturing method will be described. A PDP using the phosphor paste of the present invention is disclosed in, for example, Japanese Patent Laid-Open No. 10-1954.
It can be produced by a known method such as that disclosed in Japanese Patent Publication No. 28. The phosphor paste of the present invention is prepared using each of blue, green, and red phosphors for VUV-excited light-emitting devices having a BET specific surface area of 1 m ² / g or more. The paste is applied by a method such as screen printing on the inner surface of the back substrate, which is partitioned by partition walls and has a stripe-shaped substrate surface provided with address electrodes and the partition surface, which is dried and then heated at a temperature of 350 ° C. or higher. Each phosphor layer is formed. A surface glass substrate having a transparent electrode and a bus electrode in a direction orthogonal to the phosphor layer and having a dielectric layer and a protective layer provided on the inner surface is laminated and adhered to this, and the interior is evacuated to a low pressure such as Xe or Ne. The PDP can be manufactured by filling the rare gas described above and forming a discharge space.

[0031]

EXAMPLES Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. The viscosity (10 rpm, 25 ° C.) and the thixotropy index TI were used as the indexes for judging the dispersibility of the phosphor. In addition, a paste composition having a lower viscosity and a higher TI has a better dispersibility. The thixotropy index was calculated from the following formula. TI = log (η2 / η1) / log (D1 / D2) D1 = 1 rpm η1: viscosity at 1 rpm D2 = 10 rpm η2: viscosity at 10 rpm is measured by RVDV-I + C manufactured by BROOKFIELD.
P type (spindle CPE-52) was used.

Example 1 Phosphor BaMgAl ₁₀ O ₁₇ : Eu (BET specific surface area 1.
2 m ² / g) 100 parts by weight, nonionic surfactant (bis (2-hydroxyethyl) alkylamine, structural formula is R ¹ N (CH ₂ CH ₂ OH) ₂ (R ¹ is C _{14 to} C ₁₈ Mixture), manufactured by Lion Akzo) 2 parts by weight, binder resin (ethyl cellulose) 2.5 parts by weight, solvent (2,2,2)
48 parts by weight of 4-trimethyl-1,3-pentanediol monoisobutyrate) was dispersed and mixed by a ball mill. The viscosity of the obtained paste was measured (Table 1).

Comparative Example 1 Phosphor BaMgAl ₁₀ O ₁₇ : Eu (BET specific surface area 1.
2 m ² / g) 100 parts by weight, binder resin (ethyl cellulose) 2.5 parts by weight, solvent (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate) 4
8 parts by weight were dispersed and mixed with a ball mill. The viscosity of the obtained paste was measured (Table 1).

Example 2 Phosphor BaMgAl ₁₀ O ₁₇ : Eu (BET specific surface area 6 m
² / g) 100 parts by weight, ² parts by weight of the same nonionic surfactant as in Example 1, binder resin (ethyl cellulose)
2.5 parts by weight of solvent (2,2,4-trimethyl-1,3
65 parts by weight of (pentanediol monoisobutyrate) was dispersed and mixed by a ball mill. The viscosity of the obtained paste was measured (Table 1).

Comparative Example 2 Phosphor BaMgAl ₁₀ O ₁₇ : Eu (BET specific surface area 6 m
² / g) 100 parts by weight, binder resin (ethyl cellulose) 2.5 parts by weight, solvent (2,2,4-trimethyl-)
65 parts by weight of 1,3-pentanediol monoisobutyrate) were dispersed and mixed by a ball mill. The viscosity of the obtained paste was measured (Table 1).

Example 3 Phosphor BaMgAl ₁₀ O ₁₇ : Eu (BET specific surface area 1.
2 m ² / g) 100 parts by weight, nonionic surfactant (bis (2-hydroxyethyl) alkylamine, structural formula is R ¹ N (CH ₂ CH ₂ OH) ₂ (R ¹ is C _{14 to} C ₁₈ Mixture), manufactured by Lion Akzo) 2 parts by weight, binder resin (ethyl cellulose) 20 parts by weight, solvent (2,2,4)
-Trimethyl-1,3-pentanediol monoisobutyrate) (163 parts by weight) was dispersed and mixed by a ball mill. The viscosity of the obtained paste was measured (Table 1).

Comparative Example 3 Phosphor BaMgAl ₁₀ O ₁₇ : Eu (BET specific surface area 1.
2 m ² / g) 100 parts by weight, binder resin (ethyl cellulose) 20 parts by weight, solvent (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate) 16
3 parts by weight were dispersed and mixed by a ball mill. The viscosity of the obtained paste was measured (Table 1).

[0038]

[Table 1]

Example 4 Phosphor Y ₂ O ₃ : Eu (BET specific surface area 3 m ² / g) 10
0 parts by weight, 2 parts by weight of the same surfactant as in Example 1, 2.5 parts by weight of binder (ethyl cellulose), solvent (2.
39 parts by weight of 2,4-trimethyl-1,3-pentanediol monoisobutyrate) were premixed. The obtained preliminary mixture was put on a three-roll mill to disperse and mix the phosphor. The viscosity of the obtained phosphor paste was measured. The coating test was carried out by coating a 2 cm square surface by a screen printing method using a 150 mesh screen. (Table 2)

Comparative Example 4 Example 3 except that no nonionic surfactant was added.
A phosphor paste was prepared in the same manner as in. The obtained paste was subjected to viscosity measurement and coating test (Table 2). It was shown that the dispersibility was better when the nonionic surfactant was added.

[0041]

[Table 2]

[0042]

The phosphor paste of the present invention has a high BET.
It is a paste in which phosphor particles having a specific surface area are sufficiently dispersed and is easy to apply. Therefore, it is particularly suitable for a vacuum ultraviolet ray excited light emitting device such as a plasma display (PDP) and a mercury-free lamp, and is industrially extremely useful. It is useful.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01J 61/46 H01J 61/46 F term (reference) 4H001 CA01 4J037 AA08 CB15 CC02 CC13 CC15 CC16 CC22 CC24 CC26 DD23 DD24 EE08 EE43 FF02 5C040 FA10 GG09 JA02 JA03 JA13 KA14 KA17 KB04 KB24 MA22 MA26 5C043 AA02 AA13 DD28 EB07

Claims (3)

[Claims] 1. A non-ionic surfactant comprising a compound containing a hydroxyalkyl group and a nitrogen atom, a phosphor having a BET specific surface area of 1 m ² / g or more, a binder and a solvent. Phosphor paste. 2. The nonionic surfactant has the chemical formula RN.
(R'-OH) ₂ , RNH (R'-OH), RCON
(R'-OH) ₂ , RCONH (R'-OH), RN
(R'-OH) R''N (R'-OH) ₂ , RNH
R ″ N (R′—OH) ₂ (where R is an alkyl or alkenyl group having 8 to 18 carbon atoms, R ′, R ″
Is an alkylene group having 1 to 4 carbon atoms. The phosphor paste according to claim 1, which is one or more selected from the group consisting of compounds represented by the formula (1). 3. A VUV-excited light-emitting device using a phosphor layer obtained by applying the phosphor paste according to claim 1 onto a substrate and heating it.