JPWO2008149817A1 - Phosphor paste composition - Google Patents

Abstract

An object of the present invention is to provide a phosphor paste composition that can be printed by screen printing, has a good phosphor dispersibility, is excellent in storage stability, and can be degreased at a low temperature.
The present invention is a phosphor paste composition containing a (meth) acrylic resin, a phosphor, an organic solvent, and a polyoxyethylene sorbitan fatty acid ester having an HLB value of 9 or more, using a B-type viscometer at 23 ° C. The phosphor paste composition has a viscosity of 8 to 40 Pa · s when measured with the probe rotation speed set to 10 rpm.

Description

The present invention relates to a phosphor paste composition that can be printed by screen printing, has good phosphor dispersibility, excellent storage stability, and can be degreased at low temperatures.

In recent years, inorganic fine particle paste compositions in which inorganic fine particles such as conductive powder and ceramic powder are dispersed in a binder resin have been used to obtain fired bodies having various shapes. In particular, a phosphor paste composition in which a phosphor is dispersed in a binder resin as inorganic fine particles is used in organic EL and the like, and demand is increasing in recent years.
The phosphor paste composition is fired in a required shape by performing firing after processing into a predetermined shape by, for example, screen printing, a coating method using a doctor blade, a casting method for processing into a sheet shape, etc. It can be a body. Among these, screen printing is a method particularly suitable for mass production.

The phosphor paste composition used in screen printing preferably has thixotropic properties. The thixotropy is, for example, when the viscosity is evaluated with a rotational viscometer, the viscosity is low when the rotational speed is high (displacement with a high strain rate), and the viscosity is high when the rotational speed is low (displacement with a low strain rate). Is the nature. The phosphor paste composition has a sufficiently low viscosity during coating and is easy to apply, while it has a sufficiently high viscosity and does not cast by its own weight when allowed to stand and dry after coating. Is required.

As the binder resin used in the phosphor paste composition, a cellulose resin such as ethyl cellulose having thixotropy is generally used. However, a phosphor paste composition in which a phosphor is dispersed in a cellulose resin does not thermally decompose unless fired at a high temperature. Therefore, there are problems such that a large amount of energy is required in the production process, and the baking time becomes long.

In order to solve such a problem, a method using an acrylic resin that can be degreased at a lower temperature than a cellulose resin has been studied. For example, Patent Document 1 discloses a phosphor paste composition using an acrylic resin.
However, such a phosphor paste composition has very strong adhesiveness due to the acrylic resin, and when screen printing is performed, the screen printing plate is spun and is difficult to handle during screen printing. In addition, the printed image may be thinner than when a cellulose resin having low adhesiveness is used. Moreover, it was necessary to wash the screen printing plate for a long time in order to remove the acrylic resin. Although the tackiness can be reduced by reducing the amount of acrylic resin added, the viscosity of the phosphor paste composition is significantly reduced accordingly, and when phosphors with high specific gravity are dispersed, the phosphors settle. There is a problem that the so-called “storage stability”, that is, the agglomeration or aggregation, becomes worse.
Therefore, a method of increasing the molecular weight of the acrylic resin to reduce the addition amount of the acrylic resin, increase the viscosity of the phosphor paste composition, and maintain the storage stability has been considered. However, when the molecular weight of the acrylic resin is increased, there has been a problem in that the yarn is generated violently and screen printing becomes difficult.

For such a problem, for example, Patent Document 2 discloses a method of adding a thixotropic agent such as fatty acid amide, hydrogenated castor oil, or polyamino acid to the phosphor paste composition. However, these thixotropic agents are all additives for increasing the viscosity of the phosphor paste composition, and are not sufficient for obtaining a phosphor paste composition suitable for screen printing. Furthermore, there has been a problem that the thermal decomposability of the phosphor paste composition deteriorates and a residue remains.

Patent Document 3 discloses a method of adding a compound having one or more carboxyl groups such as stearic acid to the phosphor paste composition in order to improve the dispersibility of the phosphor. By adding a compound having at least one carboxyl group, the carboxyl group is adsorbed on the surface of the phosphor to neutralize the surface potential, or inactivate the hydrogen bonding site, and the steric effect of the portion other than the carboxyl group It is disclosed that aggregation is suppressed by this and the dispersibility of the phosphor is improved. However, with this method, it is difficult to maintain long-term storage stability, and the phosphor may settle or aggregate. Moreover, the phosphor paste composition having a low viscosity has a significant change in viscosity, and it has been difficult to obtain a phosphor paste composition suitable for screen printing.

In Patent Document 4, in order to improve the dispersibility of the phosphor, the phosphor paste composition is composed of a compound containing a hydroxyalkyl group such as bis (2-hydroxyethyl) alkylamine and a nitrogen atom and a nonionic property. A method of adding a surfactant is disclosed.
However, since the phosphor paste composition disclosed in the example of Patent Document 3 has a viscosity of 4.4 to 5.0 Pa · s, the phosphor immediately after being dispersed exhibits good dispersibility. However, it sometimes settled over time. Further, there is a problem that the thermal decomposability of the phosphor paste composition deteriorates and a residue remains.
Thus, it has been very difficult to improve the screen printability by reducing the adhesiveness of the phosphor paste composition while ensuring the dispersibility of the phosphor.
Japanese Patent Laid-Open No. 9-012979 JP 2000-144124 A JP 2003-257314 A JP 2003-292947 A

An object of the present invention is to provide a phosphor paste composition that can be printed by screen printing, has good dispersibility of phosphor, is excellent in storage stability, and can be degreased at a low temperature. And

The present invention is a phosphor paste composition containing a (meth) acrylic resin, a phosphor, an organic solvent, and a polyoxyethylene sorbitan fatty acid ester having an HLB value of 9 or more, using a B-type viscometer at 23 ° C. The phosphor paste composition has a viscosity of 8 to 40 Pa · s when measured with the probe rotation speed set to 10 rpm.
The present invention is described in detail below.

The present inventors use (meth) acrylic resin as a binder resin in designing a phosphor paste for screen printing, and reduce the amount of (meth) acrylic resin added, thereby degreasing the phosphor paste composition at a low temperature. It has been studied to improve the screen printing property and storage stability. However, merely adjusting the viscosity by reducing the addition amount of the acrylic resin has a problem that the screen printing property is poor, and the phosphor is settled or aggregates, resulting in poor storage stability. Therefore, as a result of further intensive studies, the present inventors used (meth) acrylic resin as the binder resin and polyoxyethylene sorbitan fatty acid ester having a specific structure as the surfactant, and the viscosity of the phosphor paste composition. By adjusting, it discovered that the phosphor paste composition which was excellent in screen-printing property and storage stability, and was degreasable at low temperature could be obtained, and came to complete this invention.

The phosphor paste composition of the present invention contains a (meth) acrylic resin, a phosphor, an organic solvent, and a polyoxyethylene sorbitan fatty acid ester having an HLB value of 9 or more.

The phosphor paste composition of the present invention contains a (meth) acrylic resin. The (meth) acrylic resin has a role as a binder.

The (meth) acrylic resin is not particularly limited as long as it is a (meth) acrylic resin that can be degreased at a low temperature (400 ° C. or lower). For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl ( (Meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, n-stearyl ( Homopolymers of (meth) acrylate monomers such as (meth) acrylate and benzyl (meth) acrylate, and the above (meth) acrylate monomers, polypropylene oxide, polymethylethylene oxide, polyethylethylene oxide, polytri Chiren'okishido, and it can be used a copolymer of having a polyoxyalkylene structure of polytetramethylene oxide and the like (meth) acrylate monomer. Here, for example, (meth) acrylate means acrylate or methacrylate.
Especially, since the viscosity of the phosphor paste composition suitable for screen printability can be obtained while reducing the content of (meth) acrylic resin, the glass transition temperature (Tg) is high and degreasing is performed at a low temperature. It is preferable to contain a methyl methacrylate monomer which can be used as a polymer component, and polymethyl methacrylate which is a homopolymer of a methyl methacrylate monomer is particularly preferable.

The (meth) acrylic resin preferably has a polar group at the end of the molecular chain. Thereby, printability improves and it can print suitably by screen printing.
If the above polar group is present in the molecular side chain, the (meth) acrylic resin and the organic solvent are compatible, the viscosity of the resin solution becomes extremely low, and more resin must be added to maintain the viscosity. Occurs. As a result, since the adhesiveness is increased, the print pattern may be blurred or printing may not be possible.
Due to the presence of the polar group at the end of the molecular chain instead of the side chain, the (meth) acrylic resin and the organic solvent are not compatible with each other, exhibit appropriate phase separation (microphase separation), have a low molecular weight, and The viscosity necessary for printing can be secured even with a small resin content. As a result, the phosphor paste composition has less adhesiveness, and it is difficult for the yarn to be drawn, so that the printability is improved.
Among them, even if a phosphor paste composition stored for a long period of time is used, a good printing pattern can be obtained and the storage stability is excellent. Therefore, the polar group is present in the molecular side chain of the (meth) acrylic resin. It is preferable to use a (meth) acrylic resin that does not exist and exists only at the molecular chain end.

The polar group is particularly preferably a hydrogen bonding functional group.
The hydrogen bonding functional group is not particularly limited, and examples thereof include a hydroxyl group, a carboxyl group, an amino group, and a polyoxyalkylene ether group. Among these, a hydroxyl group and a carboxyl group are preferable because the (meth) acrylic resin can be thermally decomposed at a low temperature without residue.
In addition, at least one hydrogen-bonding functional group may be included, but the larger the number, the more stable the phase separation structure and the lower the adhesiveness of the phosphor paste composition. The effect is improved and effective.

As a method for introducing a polar group into the molecular chain terminal of the (meth) acrylic resin, specifically, for example, a free radical polymerization method using the above-described (meth) acrylate monomer under a chain transfer agent having a polar group. And a method of polymerization or copolymerization by a conventionally known method such as a living radical polymerization method, an iniferter polymerization method, an anionic polymerization method, or a living anion polymerization method.
In addition, the polar group can be introduced at the end of the (meth) acrylic molecular chain by using a polymerization initiator such as an organic peroxide initiator having a polar group or an azo initiator.
The introduction of a polar group at the molecular chain end of the (meth) acrylic resin can be confirmed by, for example, ¹³ C-NMR.

As the chain transfer agent having a polar group, a chain transfer agent having a hydrogen bonding functional group is particularly preferable. For example, mercaptopropanediol having a hydroxyl group as a hydrogen bonding functional group, thioglycerol, carboxyl as a hydrogen bonding functional group. Examples thereof include mercaptosuccinic acid having a group, mercaptoacetic acid, and aminoethanethiol having an amino group as a hydrogen bonding functional group.

As the organic peroxide initiator having a polar group, an organic peroxide initiator having a hydrogen bonding functional group is particularly preferable. For example, P-menthane hydroperoxide (“Permenta H” manufactured by NOF Corporation), diisopropyl Benzene hydroperoxide (Nippon "Parkmill P"), 1, 2, 3, 3-tetramethylbutyl hydroperoxide (Nippon "Perocta H"), cumene hydroperoxide (Nippon "Parkmill H-" 80 "), t-butyl hydroperoxide (" Perbutyl H-69 "manufactured by NOF Corporation), cyclohexanone peroxide (" Perhexa H "manufactured by NOF Corporation), 1, 1, 3, 3-tetramethylbutyl hydroperoxide , T-butyl hydroperoxide, t-amyl hydroperoxide, Disuccinic acid peroxide (Parroyl SA).

As the azo initiator having the polar group, an azo initiator having a hydrogen bonding functional group is particularly preferable. For example, 2,2′-azobis [N- (2carboxyethyl) -2-methylpropionamidine] Polymerization initiators having many hydroxyl groups and carboxyl groups such as hydrate and 2,2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide} Can be suitably used.

The minimum with a preferable weight average molecular weight by polystyrene conversion of the said (meth) acrylic resin is 5000, and a preferable upper limit is 50000. When the weight average molecular weight is less than 5,000, the (meth) acrylic resin and the organic solvent cannot exhibit appropriate phase separation (microphase separation), and thus the viscosity necessary for screen printing cannot be obtained. is there. A more preferable lower limit of the weight average molecular weight is 10,000. When the weight average molecular weight exceeds 50000, the yarn paste of the phosphor paste composition becomes high, so that the yarn is likely to be generated and the screen printability may be deteriorated. The more preferable upper limit of the weight average molecular weight is 40000, and the more preferable upper limit is 30000. In particular, the weight average molecular weight of the (meth) acrylic resin is preferably 10,000 to 30,000 because a clear image can be obtained during screen printing.
In the conventional phosphor paste composition, a (meth) acrylic resin having a relatively high molecular weight has been used in order to maintain a viscosity capable of screen printing. In contrast, the phosphor paste composition of the present invention is good even when a (meth) acrylic resin having a weight average molecular weight in the range of 5000 to 50000 is used by appropriately phase-separating (microphase separation). The screen printability can be demonstrated.
In addition, the measurement of the weight average molecular weight by polystyrene conversion can be obtained by performing GPC measurement using, for example, a column LF-804 manufactured by SHOKO as a column.

The molecular weight distribution (weight average molecular weight / number average molecular weight = Mw / Mn) of the (meth) acrylic resin is not particularly limited, but the preferred upper limit is 3. If the molecular weight distribution exceeds 3, monomers or oligomers that are low molecular weight components act as plasticizers, and if the phosphor paste composition does not have sufficient viscosity, or if it contains a high molecular weight component ( In some cases, the yarn may be drawn by a (meth) acrylic resin, which may cause a problem during screen printing. A more preferable upper limit of the molecular weight distribution is 2.5.

Although it does not specifically limit as content of the said (meth) acrylic resin in the fluorescent substance paste composition of this invention, A preferable minimum is 5 weight% and a preferable upper limit is 25 weight%. When the content of the (meth) acrylic resin is less than 5% by weight, a phosphor paste composition having a viscosity suitable for screen printing may not be obtained. If the content of the (meth) acrylic resin exceeds 25% by weight, the viscosity of the phosphor paste composition is too high, making screen printing difficult and increasing the adhesiveness. Yarn may be easily generated.

When the (meth) acrylic resin after the polymerization reaction is used without being purified as the binder resin used in the phosphor paste composition of the present invention, a monomer or oligomer that is a low molecular weight component may be used as the phosphor paste composition. It is preferable that it is not contained in. When a monomer, oligomer, or the like, which is a low molecular weight component, is contained in the phosphor paste composition, the monomer, oligomer, or the like may act as a plasticizer and reduce the viscosity.

The phosphor paste composition of the present invention contains a polyoxyethylene sorbitan fatty acid ester having an HLB value of 9 or more.

Conventionally, in a phosphor paste composition, when a (meth) acrylic resin is used as a binder resin, various dispersants and surfactants are used in order to improve the dispersibility and screen printability of the phosphor. Has been studied. In particular, in a phosphor paste composition having a low viscosity, the dispersibility and screen printability of the phosphor cannot be sufficiently ensured, and the dispersibility and screen printability may be significantly lowered depending on the type of phosphor used. It was.
In the present invention, by using such a polyoxyethylene sorbitan fatty acid ester as a surfactant, the dispersibility and screen printability are remarkably improved without depending on the phosphor composition and without deteriorating the degreasing property of the binder. Can be made.

The polyoxyethylene sorbitan fatty acid ester has an HLB value of 9 or more. When the HLB value is 9 or more, a phosphor paste composition having excellent phosphor dispersibility and screen printability can be obtained. When the HLB value of the polyoxyethylene sorbitan fatty acid ester is less than 9, the viscosity of the phosphor paste composition of the present invention decreases.
When the polyoxyethylene sorbitan fatty acid ester is contained, the dispersibility of the phosphor is improved, but the viscosity of the phosphor paste composition may be lowered. In the present invention, by setting the HLB value of the polyoxyethylene sorbitan fatty acid ester to 9 or more, a phosphor paste composition suitable for screen printing can be obtained without reducing the viscosity of the phosphor paste composition. it can. The preferable lower limit of 9.5 and the preferable upper limit of the HLB value are 17.0.
Here, the HLB value is an index indicating the balance of hydrophilicity or lipophilicity of the surfactant. The closer to 0, the higher the lipophilicity, and the closer to 20, the higher the hydrophilicity. The HLB value is, for example, the following griffin formula [(molecular weight of hydrophilic portion) / (total molecular weight) × 100] / 5.
Is a value calculated using.

The polyoxyethylene sorbitan fatty acid ester is a compound represented by the following chemical formula (1) and / or a compound represented by the following chemical formula (2) or a compound represented by the following chemical formula (3). Is preferred.

R ¹ , R ² and R ³ are C _n H _2n-1 or C _n H _{2n + 1} (n is an integer of 5 or more), and a + b + c = 20, d + e + f = 20, and g + h + i + j = 20.

R ¹ , R ² and R ³ in the above chemical formula are C _n H _2n-1 or C _n H _{2n + 1} (n is an integer of 5 or more). When n is less than 5, the polyoxyethylene sorbitan fatty acid ester does not play a role as a surfactant, and the dispersibility of the phosphor in the phosphor paste composition is lowered or the screen printability is poor. There is.
In the above chemical formula, a + b + c = 20, d + e + f = 20, and g + h + i + j = 20.
Here, a + b + c = 20 means that a, b, and c are each an integer of 1 or more, and the sum of a, b, and c is 20.
D + e + f = 20 means that d, e, and f are each an integer of 1 or more, and the sum of d, e, and f is 20.
Also, g + h + i + j = 20 means that g, h, i, and j are each an integer of 1 or more, and the total sum of g, h, i, and j is 20.

Examples of the polyoxyethylene sorbitan fatty acid ester represented by the chemical formula (1) and / or the chemical formula (2) include, for example, polyoxyethylene (20) sorbitan monolaurate (“Leodol TW-L120” HLB value manufactured by Kao Corporation). 16.7), polyoxyethylene (20) sorbitan monostearate ("Leodol TW-S120V" manufactured by Kao Corporation, HLB value 10.5), polyoxyethylene (20) sorbitan monooleate ("Leodol TW-" manufactured by Kao Corporation) O120V "HLB value 15), polyoxyethylene (20) sorbitan monopalmitate (" Reodol TW-P120 "HLB value 15.6 manufactured by Kao Corporation) and the like.

Examples of the polyoxyethylene sorbitan fatty acid ester represented by the chemical formula (3) include polyoxyethylene sorbitan monococonut fatty acid ester (“Solgen TW-20” HLB value 16.7 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), polyoxy Ethylene sorbitan monostearate ("Solgen TW-60" HLB value 14.9 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), polyoxyethylene sorbitan monooleate ("Solgen TW-80" HLB value 15 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Can be mentioned.

Although it does not specifically limit as content of the said polyoxyethylene sorbitan fatty acid ester in the fluorescent substance paste composition of this invention, A preferable minimum is 0.01 weight% and a preferable upper limit is 5 weight%. When the content of the polyoxyethylene sorbitan fatty acid ester is less than 0.01% by weight, the effect of improving the dispersibility of the phosphor paste composition and the effect of improving the screen printability may not be exhibited. When content of the said polyoxyethylene sorbitan fatty acid ester exceeds 5 weight%, the viscosity of a fluorescent substance paste composition will fall and it may not be suitable for screen printing. The minimum with more preferable content of the said polyoxyethylene sorbitan fatty acid ester is 0.05 weight%, and a more preferable upper limit is 1 weight%.

In addition, in order that the phosphor paste composition of the present invention stabilizes an appropriate phase separation (microphase separation), the phosphor paste composition of the present invention contains a polyoxyethylene alkyl ether having an HLB value of 11 or more. By containing, the phosphor paste composition which is further excellent in screen printability can be obtained. The polyoxyethylene alkyl ether having an HLB value of 11 or more is not particularly limited, and examples thereof include polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether and the like.

The phosphor paste composition of the present invention preferably contains a nonionic surfactant having an HLB value of 10 or more in combination with the polyoxyethylene sorbitan fatty acid ester.
The nonionic surfactant having an HLB value of 10 or more is not particularly limited, but a nonionic surfactant obtained by adding an alkylene ether to a fatty chain is preferable, and specifically, for example, polyoxyethylene lauryl ether, Polyoxyethylene cetyl ether and the like are preferably used. The nonionic surfactant has good thermal decomposability, but if added in a large amount, the thermal decomposition temperature of the phosphor paste composition may increase or a residue may be generated. The preferable upper limit of the content of the nonionic surfactant in is 5% by weight.

The phosphor paste composition of the present invention contains a phosphor.
The phosphor is not particularly limited, and examples thereof include phosphors used for various purposes such as CRT phosphors, lamp phosphors, PDP phosphors, X-ray phosphors, and phosphorescent phosphors. Specifically, for example, Y ₂ O ₃ : Eu, Y ₂ O ₂ S: Eu, YBO ₃ : Eu, (Y, Gd) BO ₃ : Eu, Y (P, V) O ₄ : Eu, GdBO ₃ : Eu, Y ₂ SiO ₅ : Eu, Y ₃ Al ₅ O ₁₂ : Eu, ScBO ₃ : Eu, LuBO ₃ : Eu and other red phosphors, ZnS: Cu, Al, LaPO ₄ : Ce, Tb, CaMgSi ₂ O _{6 : Eu, (Ba, Sr,} Mg) O · aAl 2 O 3 Mn, (Y, Gd) BO 3: Tb, Zn 2 SiO 4: Mn, BaAl 12 O 19: Mn, BaMgAl 10 O 17: Mn, BaMgAl _{10 O 17: Mn, Eu,} BaMgAl 14 O 23: Mn, CaAl 12 O 19: Mn, SrAl 12 O 19: Mn, YBO 3: Tb, LuBO 3: Tb, GdBO 3: Tb, Green phosphor such as Gd ₂ O ₂ S: Tb, ScBO ₃ : Tb, Sr ₄ Si ₃ O ₈ Cl ₄ : Eu, ZnS: Ag, Al, (SrCaBaMg) ₅ (PO ₄ ) ₃ Cl: Eu, BaMgAl ₁₀ O ₁₇ : Eu, BaMgAl ₁₄ O ₂₃ : Eu, Y ₂ SiO ₅ : Ce, CaWO ₄ , CaWO ₄ : Pb, (Ca, Sr) MgSi ₂ O ₆ : Eu, (Ca, Sr) Mg ₂ Si ₂ O ₇ : Eu, (Ca, Sr) ₂ MgSi ₂ O ₇ : Blue phosphor such as Eu, Sr ₄ Al ₁₄ O ₂₅ : Blue green phosphor such as Eu and Dy, Ca ₁₀ (PO ₄ ) ₆ FCl: Sb, Mn White phosphors and the like.

In the phosphor paste composition of the present invention, since it is excellent in dispersibility, blue phosphors such as BaMgAl ₁₀ O ₁₇ : Eu, green phosphors such as Zn ₂ SiO ₄ : Mn, (Y, The effect of the present invention can be sufficiently exerted when a red phosphor such as Gd) BO ₃ : Eu is used. In particular, as described later, by using glycerin, polycarboxylic acid, or polyether ester amine salt as a dispersant, further excellent dispersibility can be ensured.

The phosphor paste composition of the present invention can also be suitably used when it contains the red phosphor.
In general, since the red phosphor has a higher specific gravity than other phosphors, when the phosphor paste composition contains a red phosphor, the red phosphor easily settles and the storage stability is not sufficient. . On the other hand, in the phosphor paste composition of the present invention, when an imidazole compound to be described later is added, even when the red phosphor is contained, the red phosphor does not settle and the storage stability is excellent. This is probably because the imidazole compound forms a structure that suppresses the precipitation of the red phosphor.

Although it does not specifically limit as content of the said fluorescent substance, With respect to 100 weight part of binder resin compositions which are a mixture of a (meth) acrylic resin, an organic solvent, and polyoxyethylene sorbitan fatty acid ester, The preferable lower limit of the content is 10 parts by weight, and the preferable upper limit is 300 parts by weight. When the phosphor content is less than 10 parts by weight, a phosphor paste composition having a viscosity suitable for screen printing may not be obtained. When the content exceeds 300 parts by weight, the phosphor is added to the binder resin composition. It may be difficult to disperse. A more preferable lower limit of the phosphor content is 50 parts by weight, and a more preferable upper limit is 250 parts by weight.

The phosphor paste composition of the present invention contains an organic solvent.
The organic solvent preferably has at least one hydroxyl group or acetoxy group in the molecule. As a result, appropriate phase separation (microphase separation) between the (meth) acrylic resin having a polar group at the molecular chain terminal and an organic solvent is easily developed, and the viscosity (thixotropic) suitable for screen printing is maintained. However, the content of the (meth) acrylic resin is reduced, and degreasing at a low temperature becomes easy.

Although it does not specifically limit as a boiling point of the said organic solvent, A preferable minimum is 170 degreeC and a preferable upper limit is 280 degreeC. When the boiling point of the organic solvent is less than 170 ° C., the organic solvent volatilizes during screen printing, and the work efficiency of screen printing may deteriorate. When the boiling point exceeds 280 ° C., the phosphor paste composition of the present invention Things may not be defatted at low temperatures. A more preferable lower limit of the boiling point of the organic solvent is 200 ° C., and a more preferable upper limit is 250 ° C.

The organic solvent is not particularly limited. For example, ethylene glycol ethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoisobutyl ether, trimethylpentanediol monoisobutyrate. , Diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, terpineol, texanol, isophorone, butyl lactate, dioctyl phthalate, dioctyl adipate, benzyl alcohol, phenyl glycol phenylpropylene glycol, cresol and the like.
Of these, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, terpineol, and texanol are preferable, and among them, diethylene glycol monoisobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether Butyl ether acetate, terpineol, and texanol are particularly suitable, and diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, terpineol, and texanol are particularly preferably used.
In addition, these organic solvents may be used independently and 2 or more types may be used together.

When the (meth) solubility parameter of the acrylic resin SP _M, the solubility parameter of the organic solvent was SP _S, the organic solvent preferably satisfies the following formula (4) or the following formula (5).
Here, the solubility parameter (hereinafter also referred to as SP value) is a value estimated from only the chemical structure of a substance as described in Polymer Engineering & Science 14 147 (1974), and is obtained by the following mathematical formula (5 ′). be able to. Those having similar SP values are compatible with each other, and those having different SP values are phase separated.
When the organic solvent satisfies the following mathematical formula (4) or the following mathematical formula (5), it becomes easy to develop an appropriate phase separation (microphase separation) between the (meth) acrylic resin and the organic solvent, and an appropriate viscosity (thixo). Property) and more excellent screen printability.

Ev: Evaporation energy (J / mol)
V: molar volume (m ³ / mol)
Δei: Evaporation energy of atoms or atomic groups (cal / mol)
ΔVi: molar volume (cm ³ / mol)

The phosphor paste composition of the present invention preferably contains a dispersant.
As the dispersant, it is preferable to use an organic compound having 3 or more hydroxyl groups, an organic compound having 3 or more carboxyl groups, a polyetherester amine salt, or the like depending on the type of phosphor. These dispersants have a role of improving the storage stability of the phosphor paste composition. In particular, when using a low-viscosity phosphor paste composition, it is important to select a dispersant that matches the phosphor composition in order to ensure the dispersibility of the phosphor.

The organic compound having three or more hydroxyl groups is not particularly limited, and examples thereof include polyols such as glycerin, polypropylene glycol, and polytetramethylene glycol.

The organic compound having three or more carbonyl groups is not particularly limited, and examples thereof include α-olefin-maleic anhydride copolymers, unsaturated polycarboxylic acids, and aliphatic polyvalent carboxylic acids.

These dispersants are excellent in dispersion even when a blue phosphor such as BaMgAl ₁₀ O ₁₇ : Eu is used as the phosphor of the low-viscosity phosphor paste composition due to a synergistic effect with the polyoxyethylene sorbitan fatty acid ester. Can be realized. In particular, when glycerin or a polyvalent carboxylic acid compound is used as a dispersant, a phosphor paste composition that exhibits extremely excellent storage stability can be obtained.

Although it does not specifically limit as content of the dispersing agent in the fluorescent substance paste composition of this invention, A preferable minimum is 0.1 weight% and a preferable upper limit is 5 weight%. When the content of the dispersant is less than 0.1% by weight, the dispersed state of the phosphor in the phosphor paste composition cannot be maintained, and the phosphor is stored by being settled or aggregated. Problems with stability may arise. Even if the content of the dispersant exceeds 5% by weight, further storage stability may not be obtained, or the thermal decomposability of the phosphor paste composition may be lowered. A more preferable lower limit of the content of the organic compound having three or more hydroxyl groups is 1% by weight, and a more preferable upper limit is 3% by weight.

The phosphor paste composition of the present invention preferably further contains an imidazole compound represented by the following chemical formula (6) or the following chemical formula (7).

Ｒ^４は、Ｃ_ｎＨ_２ｎ＋１（ｎは、５以上の整数）、又は、Ｃ_ｎＨ_２ｎ―１（ｎは、５以上の整数）を示し、Ｒ^５は、Ｈ、Ｃ_ｎＨ_２ｎ＋１（ｎは、１〜５の整数）、又は、Ｃ_ｎＨ_２ｎＯＨ（ｎは、１〜５の整数）を示し、Ｒ^６は、Ｈ、Ｃ_ｎＨ_２ｎ＋１（ｎは、１〜５の整数）、又は、Ｃ_ｎＨ_２ｎＯＨ（ｎは、１〜５の整数）を示し、Ｒ^７は、Ｈ、又は、Ｃ_ｎＨ_２ｎ＋１（ｎは、１〜５の整数）を示す。

R ⁴ represents C _n H _{2n + 1} (n is an integer of 5 or more) or C _n H _2n-1 (n is an integer of 5 or more), and R ⁵ represents H, C _n H _{2n + 1} (n Represents an integer of 1 to 5) or C _n H _2n OH (n is an integer of 1 to 5), R ⁶ is H, C _n H _{2n + 1} (n is an integer of 1 to 5), Alternatively, C _n H _2n OH (n is an integer of 1 to 5), R ⁷ is H or C _n H _{2n + 1} (n is an integer of 1 to 5).

Ｒ^８は、Ｃ_ｎＨ_２ｎ＋１（ｎは、５以上の整数）、又は、Ｃ_ｎＨ_２ｎ―１（ｎは、５以上の整数）を示し、Ｒ^９は、Ｈ、Ｃ_ｎＨ_２ｎ＋１（ｎは、１〜５の整数）、又は、Ｃ_ｎＨ_２ｎＯＨ（ｎは、１〜５の整数）を示し、Ｒ^１０は、Ｈ、Ｃ_ｎＨ_２ｎ＋１（ｎは、１〜５の整数）、又は、Ｃ_ｎＨ_２ｎＯＨ（ｎは、１〜５の整数）を示し、Ｒ^１１は、Ｈ、又は、Ｃ_ｎＨ_２ｎ＋１（ｎは、１〜５の整数）を示す。

R ⁸ represents C _n H _{2n + 1} (n is an integer of 5 or more) or C _n H _2n-1 (n is an integer of 5 or more), and R ⁹ represents H, C _n H _{2n + 1} (n Represents an integer of 1 to 5) or C _n H _2n OH (n is an integer of 1 to 5), R ¹⁰ is H, C _n H _{2n + 1} (n is an integer of 1 to 5), _or, (the n, 1 to 5 integer) C _n H 2n OH ^{indicates, R 11} is, H, _or, (the n, 1 to 5 integer) C _{n H 2n +} 1 illustrates a.

In the present specification, the imidazole compound means an imidazoline compound (dihydroimidazole) represented by the chemical formula (6) and an imidazole compound represented by the chemical formula (7).
Especially, it is preferable that the fluorescent substance paste composition of this invention contains the imidazole type compound represented by the said Chemical formula (6).

In the chemical formula (6), R ⁴ has a structure represented by C _n H _{2n + 1} (n is an integer of 5 or more) or C _n H _2n-1 (n is an integer of 5 or more). R ⁴ is preferably a structure represented by C _n H _{2n + 1} (n is an integer of 5 to 30) or C _n H _2n-1 (n is an integer of 5 to 30). When n is less than 5, the storage stability of the phosphor paste composition may not be obtained, and when n is more than 30, the chain length of the alkyl group or alkenyl group is long. Residues may be generated.
Further, R ⁴ is a structure represented by C _n H _{2n + 1} (n is an integer of 10 to 20) or C _n H _2n-1 (n is an integer of 10 to 20), and linear A structure is more preferable. In the chemical formula (6), when R ⁴ has a linear structure, a phosphor paste composition having excellent storage stability can be obtained.

In the chemical formula (6), R ⁵ is a structure represented by H, C _n H _{2n + 1} (n is an integer of 1 to 5), or C _n H _2n OH (n is an integer of 1 to 5). it is not particularly limited as long, inter alia, H, or _is preferably a C _{2 H} 4 OH.

In the above chemical formula (6), R ⁶ is a structure represented by H, C _n H _{2n + 1} (n is an integer of 1 to 5), or C _n H _2n OH (n is an integer of 1 to 5). Although it will not specifically limit if it is, it is preferable that it is H especially.

In the chemical formula (6), R ⁷ is not particularly limited as long as it is a structure represented by H or C _n H _{2n + 1} (n is an integer of 1 to 5). .

In the chemical formula (7), R ⁸ has a structure represented by C _n H _{2n + 1} (n is an integer of 5 or more) or C _n H _2n-1 (n is an integer of 5 or more). R ⁸ is preferably a structure represented by C _n H _{2n + 1} (n is an integer of 5 to 30) or C _n H _2n-1 (n is an integer of 5 to 30). When n is less than 5, the storage stability of the phosphor paste composition may not be obtained, and when n is more than 30, the chain length of the alkyl group or alkenyl group is long. Residues may be generated.
R ⁸ is a structure represented by C _n H _{2n + 1} (n is an integer of 10 to 20) or C _n H _2n-1 (n is an integer of 10 to 20), and is a straight chain A structure is more preferable. In the chemical formula (7), when R ⁸ has a linear structure, a phosphor paste composition having excellent storage stability can be obtained.

In the chemical formula (7), R ⁹ is a structure represented by H, C _n H _{2n + 1} (n is an integer of 1 to 5), or C _n H _2n OH (n is an integer of 1 to 5). it is not particularly limited as long, inter alia, H, or _is preferably a C _{2 H} 4 OH.

In the chemical formula (7), R ¹⁰ is a structure represented by H, C _n H _{2n + 1} (n is an integer of 1 to 5), or C _n H _2n OH (n is an integer of 1 to 5). Although it will not specifically limit if it is, it is preferable that it is H especially.

In the chemical formula (7), R ¹¹ is not particularly limited as long as it is a structure represented by H or C _n H _{2n + 1} (n is an integer of 1 to 5). .

Specific examples of the imidazole compound are not particularly limited. Examples of the imidazole compound represented by the chemical formula (6) include 2- (8-heptadecenyl) -2-imidazoline-1-ethanol (R ⁴ is C ₇ H ₁₄ —CH═CH—C ₈ H ₁₇ , R ⁵ is C ₂ H ₄ OH, R ⁶ is H, R ⁷ is H), 2-undecylimidazoline (R ⁴ is C ₁₁ H ₂₃ , R ⁵ H, R ⁶ is H, R ⁷ is H), 2-heptadecylimidazoline (R ⁴ is C ₁₇ H ₃₅ , R ⁵ is H, R ⁶ is H, and R ⁷ is H). Among these, when 2- (8-heptadecenyl) -2-imidazoline-1-ethanol is used, a phosphor paste composition having excellent storage stability can be obtained, and therefore, it can be suitably used.

Examples of the imidazole compound represented by the chemical formula (7) include 2- (8-heptadecenyl) -2-imidazole-1-ethanol (R ⁸ is C ₇ H ₁₄ —CH═CH—C ₈ H ₁₇ , R ^9. Is C ₂ H ₄ OH, R ¹⁰ is H, R ¹¹ is H), 2-undecylimidazole (R ⁸ is C ₁₁ H ₂₃ , R ⁹ is H, R ¹⁰ is H, R ¹¹ is H), 2- Heptadecyl imidazole (R ⁸ is C ₁₇ H ₃₅ , R ⁹ is H, R ¹⁰ is H, R ¹¹ is H), and the like.

Although it does not specifically limit as content of the said imidazole type compound in the fluorescent substance paste composition of this invention, A preferable minimum is 0.01 weight% and a preferable upper limit is 10 weight%. When the content of the imidazole compound is less than 0.01% by weight, the storage stability of the phosphor paste composition may not be sufficiently obtained. When the content exceeds 10% by weight, it may be fired at a low temperature. Residues may be generated. A more preferable lower limit of the content of the imidazole compound is 0.1% by weight, and a more preferable upper limit is 5% by weight.

The phosphor paste composition of the present invention has a lower limit of viscosity of 8 Pa · s and an upper limit of 40 Pa · s when measured at 23 ° C. using a B-type viscometer with the probe rotation speed set to 10 rpm. When the viscosity of the phosphor paste composition of the present invention is less than 8 Pa · s, the phosphor dispersion state in the phosphor paste composition cannot be maintained, and the phosphor settles or aggregates. May cause problems with storage stability. On the other hand, when the viscosity of the phosphor paste composition of the present invention exceeds 40 Pa · s, the adhesiveness is strong and the printability may be difficult.

The method for producing the phosphor paste composition of the present invention is not particularly limited and includes conventionally known methods. For example, the components are mixed using various mixers such as a ball mill, a blender mill, and a three roll. Methods and the like. Specifically, for example, after the binder resin composition is prepared by mixing the (meth) acrylic resin, the organic solvent, the dispersant, and the polyoxyethylene sorbitan fatty acid ester using a mixer, the binder resin composition A method of adding the above phosphor to the mixture and further mixing using a mixer is exemplified.

Since the phosphor paste composition of the present invention has the above-described configuration, it can perform screen printing, has excellent storage stability, and can be degreased at low temperature. Here, the low temperature degreasing means that the degreasing temperature at which 99.5% by weight of the initial weight of the binder resin is lost is a low temperature, and in the present specification, under a normal air atmosphere without nitrogen substitution, A case where the degreasing temperature is 250 to 400 ° C. is defined as low temperature degreasing.

According to the present invention, it is possible to provide a phosphor paste composition that can be screen-printed, has excellent storage stability, and can be degreased at a low temperature.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
In a 2 L separable flask equipped with a stirrer, cooler, thermometer, hot water bath, and nitrogen gas inlet, 100 parts by weight of methyl methacrylate monomer (MMA), mercaptopropanediol as a chain transfer agent, diethylene glycol monobutyl ether as an organic solvent 100 parts by weight was mixed to obtain a monomer mixture.

The obtained monomer mixture was bubbled with nitrogen gas for 20 minutes to remove dissolved oxygen, and then the temperature inside the separable flask system was replaced with nitrogen gas and heated until the hot water bath boiled with stirring. A solution of the polymerization initiator in ethyl acetate was added. During the polymerization, an ethyl acetate solution of a polymerization initiator was added several times.

Seven hours after the start of polymerization, the polymerization was terminated by cooling to room temperature. Thus, a diethylene glycol monobutyl ether solution of polymethyl methacrylate (PMMA) having a hydroxyl group only at the molecular chain terminal was obtained. When the obtained polymer was analyzed by gel permeation chromatography using a column LF-804 manufactured by SHOKO as a column, the weight average molecular weight (Mw) in terms of polystyrene was as shown in Table 1.
Diethylene glycol monobutyl ether and polyoxyethylene (POE) (20) sorbitan monolaurate (Kao Co., Ltd.) were mixed with the diethylene glycol monobutyl ether solution of polymethyl methacrylate thus obtained so as to have the composition ratio shown in Table 1. “Rheidol TW-L120”) was further added and dispersed with a high-speed disperser to prepare a binder resin composition.

To the obtained binder resin composition, Zn ₂ SiO ₄ : Mn was added as a phosphor so as to have the composition ratio described in Table 1, and sufficiently kneaded using a high-speed stirring device, and smoothed with a three-roll mill. The phosphor paste composition was prepared by performing the treatment until reaching a certain state.

(Examples 2 to 8)
Using the chain transfer agent described in Table 1, the addition amount was adjusted to obtain polymethyl methacrylate having a weight average molecular weight and a terminal functional group described in Table 1. Then, except having adjusted each component so that it might become the composition ratio described in Table 1, the binder resin composition and the fluorescent substance paste composition were produced like Example 1. FIG. Here, as the surfactant, polyoxylauryl ether ("NIKKOL BL-25" manufactured by Nikko Chemicals), POE (20) sorbitan monostearate, POE (20) sorbitan monooleate, POE (20) sorbitan mono Palmitate, polyoxyethylene sorbitan monococonut fatty acid ester (Daiichi Kogyo Seiyaku "Sorgen TW-20"), polyoxyethylene sorbitan monostearate (Daiichi Kogyo Seiyaku "Sorgen TW-60"), polyoxy Ethylene sorbitan monooleate (“Sorgen TW-80” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was used.

Example 9
In a 2 L separable flask equipped with a stirrer, cooler, thermometer, hot water bath and nitrogen gas inlet, 100 parts by weight of methyl methacrylate (MMA), 3.8 parts by weight of mercaptosuccinic acid as a chain transfer agent, organic solvent As a mixture, 100 parts by weight of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (texanol) was mixed to obtain a monomer mixture.

The obtained monomer mixture was bubbled with nitrogen gas for 20 minutes to remove dissolved oxygen, and then the temperature inside the separable flask system was replaced with nitrogen gas and heated until the hot water bath boiled with stirring. An ethyl acetate solution of a polymerization initiator was added, and further an ethyl acetate solution of a polymerization initiator was added several times during the polymerization.

Seven hours after the start of polymerization, the polymerization was terminated by cooling to room temperature. As a result, a 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate solution of polymethyl methacrylate (PMMA) having a hydroxyl group at the terminal was obtained. The obtained (meth) acrylic resin was analyzed by gel permeation chromatography using a column LF-804 manufactured by SHOKO as a column, and the weight average molecular weight in terms of polystyrene was as shown in Table 1.
With respect to the 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate solution of polymethyl methacrylate thus obtained, 2,2,4- Trimethyl-1,3-pentanediol monoisobutyrate, polyoxyethylene (POE) (20) sorbitan monolaurate (“Reodol TW-L120” manufactured by Kao Corporation) as a surfactant, and polyoxyethylene lauryl ether ( Nikko Chemicals "NIKKOL BL-25") was further added and dispersed with a high speed disperser to prepare a binder resin composition.

To the obtained binder resin composition, ZnSiO ₄ : Mn (green phosphor) as a phosphor was added so as to have a composition ratio described in Table 1, and sufficiently kneaded using a high-speed agitator, and a three-roll mill. The mixture was kneaded until a smooth state was reached, to prepare a phosphor paste composition.

(Example 10)
After obtaining polymethyl methacrylate with 0.7 parts by weight of mercaptosuccinic acid used as a chain transfer agent, the content of polymethyl methacrylate, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and A phosphor paste composition was prepared in the same manner as in Example 9 except that the surfactant was changed to the composition shown in Table 1.

(Example 11)
The phosphor paste composition was the same as in Example 9, except that a mixed solvent of α-terpineol and butyl carbitol acetate having the composition shown in Table 1 was used as the organic solvent, and the surfactant was changed to the composition shown in Table 1. A product was made.

(Example 12)
Using 0.7 parts by weight of mercaptosuccinic acid as a chain transfer agent, using a mixed solvent of α-terpineol and butyl carbitol acetate having the composition shown in Table 1 as an organic solvent, polymethyl methacrylate, an organic solvent, and a surfactant. A phosphor paste composition was prepared in the same manner as in Example 9 except that the composition shown in Table 1 was used.

(Comparative Example 1)
A phosphor paste composition was prepared in the same manner as in Example 1 except that the surfactant was not added.

(Comparative Examples 2 to 4)
A phosphor paste composition was prepared in the same manner as in Example 1 except that the surfactant described in Table 1 was used.

(Comparative Example 5)
Examples were used except that sorbitan monostearate (“Reodol SP-S10V” manufactured by Kao Corporation) and polyoxyethylene lauryl ether (“NIKKOL BL-4.2” manufactured by Nikko Chemicals) were used as surfactants. In the same manner as in Example 1, a phosphor paste composition was prepared.

(Comparative Example 6)
Example 1 except that sorbitan tristearate (“Reodol SP-S30V” manufactured by Kao Corporation) and polyoxyethylene lauryl ether (“NIKKOL BL-2” manufactured by Nikko Chemicals) were used as the surfactant. A phosphor paste composition was prepared in the same manner.

<Evaluation>
The following evaluation was performed about the binder resin composition and phosphor paste composition obtained in Examples 1-12 and Comparative Examples 1-6. The results are shown in Table 2.

(1) Viscosity Measurement The viscosity of the phosphor paste composition was measured using a B-type viscometer (“DVII + Pro” manufactured by BROOK FIELD, Inc.) at a temperature of 23 ° C. and a rotation speed of 10 rpm. η _{10 rpm} (Pa · s) was measured.

(2) Evaluation of surface roughness The obtained phosphor paste composition was applied to a slide glass (2 cm × 5 cm) to a thickness of 12.5 μm. After the slide glass coated with the phosphor paste composition was dried at 120 ° C. for 10 minutes, the surface of the phosphor paste composition coated with a surface roughness meter (“Surfcoder SE-30D” manufactured by Kosaka Laboratory Ltd.) was measured. did. The surface roughness Ra was evaluated according to the following criteria.
○: Ra = less than 1.0 μm ×: Ra = 1.0 μm or more

(3) Dispersibility evaluation The obtained phosphor paste composition was measured with a grind gauge (Ericsson, 0 to 15 μm) to measure the distribution density of the phosphor, and the scale where the aggregated phosphor appeared was observed. . However, the measurement was performed 5 times, and the average value of the scales at the places where the phosphor aggregated in 10 lines appeared was evaluated. Dispersibility was evaluated according to the following criteria.
○: Less than 10 μm ×: 10 μm or more

(4) Screen printing Screen printing was performed on the obtained phosphor paste composition in an environment of a temperature of 23 ° C. and a humidity of 50%.
For screen printing, a screen printing machine ("MT-320TV" manufactured by Microtech Co., Ltd.), screen plate making ("SX230 ° B" manufactured by Tokyo Process Service Co., Ltd. (emulsion 20 μm, screen frame 320 mm x 320 mm)), printing substrate (soda glass) 150 mm × 150 mm, thickness 15 mm), and screen printing was performed under the conditions of the following screen printer.
Gap: 2.0mm
Squeegee speed: 50 mm / s
Scraper speed: 50mm / s
Squeegee pressure: 0.25 MPa
Scraper pressure: 0.17 MPa
Back pressure: 0.10 MPa
The obtained printed image was evaluated by visual observation with a stereomicroscope.
A: There is no variation in the thickness of the printed image, the printed image is sufficiently thick, and the density is high. O: There is no variation in the thickness of the printed image. Δ: There is no variation in the thickness of the printed image, but the printed image is very large. ×: There is variation in the thickness of the printed image

(Example 13)
In a 2 L separable flask equipped with a stirrer, a cooler, a thermometer, a hot water bath and a nitrogen gas inlet, 100 parts by weight of methyl methacrylate (MMA), mercaptopropanediol as a chain transfer agent, and 100% by weight of diethylene glycol monobutyl ether as an organic solvent The monomer mixture was obtained.

The obtained monomer mixture was bubbled with nitrogen gas for 20 minutes to remove dissolved oxygen, and then the temperature inside the separable flask system was replaced with nitrogen gas and heated until the hot water bath boiled with stirring. An ethyl acetate solution of a polymerization initiator was added, and further an ethyl acetate solution of a polymerization initiator was added several times during the polymerization.

Seven hours after the start of polymerization, the polymerization was terminated by cooling to room temperature. Thereby, a diethylene glycol monobutyl ether solution of polymethyl methacrylate (PMMA) having a hydroxyl group at the terminal was obtained. The obtained (meth) acrylic resin was analyzed by gel permeation chromatography using a column LF-804 manufactured by SHOKO as a column, and the weight average molecular weight in terms of polystyrene was as shown in Table 3.

Diethylene glycol monobutyl ether, glycerin, polyoxyethylene (POE) (20) sorbitan monolaurate (Kao) with a composition ratio shown in Table 3 with respect to the diethylene glycol monobutyl ether solution of polymethyl methacrylate thus obtained. "Leodol TW-L120") and polyoxyethylene lauryl ether ("NIKKOL BL-25" manufactured by Nikko Chemicals) as a nonionic surfactant are further added and dispersed with a high-speed disperser to form a binder resin composition The thing was produced.

To the obtained binder resin composition, BaMgAl ₁₀ O ₁₇ : Eu (blue phosphor) as a phosphor was added so as to have the composition ratio shown in Table 3, and sufficiently kneaded using a high-speed agitator. The phosphor paste composition was produced by kneading with the present roll mill until it reached a smooth state.

(Examples 14, 15, 17, 18)
A phosphor paste composition was prepared in the same manner as in Example 13 except that the (meth) acrylic resin, the organic solvent, the surfactant, and the dispersant described in Table 3 were used.

(Example 16)
A diethylene glycol monobutyl ether solution of polymethyl methacrylate was prepared in the same manner as in Example 13 except that mercaptosuccinic acid was used as the chain transfer agent.
Thereafter, diethylene glycol monobutyl ether solution of the obtained polymethyl methacrylate, polyoxyethylene (POE) (20) sorbitan monolaurate (“Reodol TW-L120” manufactured by Kao Corporation) as a surfactant, and polyoxyethylene lauryl ether A phosphor paste composition was prepared in the same manner as in Example 13 except that “NIKKOL BL-25” manufactured by Nikko Chemicals was used.

(Comparative Examples 7 to 11)
Using the chain transfer agent described in Table 3, a solution of polymethyl methacrylate in diethylene glycol monobutyl ether was prepared in the same manner as in Example 13. Then, except having adjusted each component so that it might become a composition ratio of Table 3, it carried out similarly to Example 13, and produced the binder resin composition and the fluorescent substance paste composition.
Here, as the nonionic surfactant, polyoxyethylene lauryl ether (“NIKKOL BL-25” manufactured by Nikko Chemicals) was used, and the materials listed in Table 3 were used as the dispersant.

<Evaluation>
The following evaluation was performed about the binder resin composition and phosphor paste composition obtained in Examples 13 to 18 and Comparative Examples 7 to 11. The results are shown in Table 4.

(1) Viscosity evaluation The obtained phosphor paste composition was subjected to a viscosity of the phosphor paste composition using a B-type viscometer (“DVII + Pro” manufactured by BROOK FIELD, Inc.) at a temperature of 23 ° C. and a rotation speed of 10 rpm. η _{10 rpm} (Pa · s) was measured.

(2) Screen printing property The obtained phosphor paste composition was stored for 1 month in an environment of a temperature of 23 ° C. and a humidity of 50%. Thereafter, the obtained phosphor paste composition, screen printing machine (“MT-320TV” manufactured by Microtech), screen plate making (“SX230 ° B” emulsion 20 μ manufactured by Tokyo Process Service, screen frame: 320 mm × 320 mm), Using a printing substrate (soda glass: 150 mm × 150 mm, thickness: 15 mm), printing was performed under the following measurement conditions of a screen printer in an environment of a temperature of 23 ° C. and a humidity of 50%.
Gap: 2.0mm
Squeegee speed: 50 mm / s
Scraper speed: 50mm / s
Squeegee pressure: 0.25 MPa
Scraper pressure: 0.17 MPa
Back pressure: 0.10 MPa
Screen printability was evaluated according to the following criteria.
○: A beautiful printed pattern was formed.
X: The print pattern was faint or could not be printed.

(3) Storage stability After storing the obtained phosphor paste composition at 23 ° C. for 1 month, the presence or absence of phase separation of the solution (liquid material separation), phosphor sedimentation, etc. is visually confirmed. It was evaluated according to the criteria.
○: Phase separation of the solution (liquid substance separation), sedimentation of the phosphor, etc. were not confirmed.
X: The phosphor paste composition was completely phase-separated, the sedimentation of the phosphor was observed, and the viscosity of the supernatant liquid was reduced. Alternatively, the phosphor settles at the bottom of the container to form a particle layer.

(4) Decomposition temperature measurement (TG-DTA evaluation (degreasing evaluation))
The obtained binder resin composition was heated to 600 ° C. at a temperature rising temperature of 10 ° C./min in an air atmosphere using a thermal decomposition apparatus (“simultaneous SDT 2960” manufactured by TA Instruments), and the initial weight of the binder resin composition was The temperature at which 99.5% by weight of thermal decomposition was completed was measured. The binder resin composition having an end temperature of thermal decomposition of less than 400 ° C. was judged to be degreased, and the binder resin composition having a temperature of 400 ° C. or higher was judged to be degreased.

(Example 19)
In a 2 L separable flask equipped with a stirrer, cooler, thermometer, hot water bath and nitrogen gas inlet, 100 parts by weight of methyl methacrylate (MMA), mercaptosuccinic acid as a chain transfer agent, and 100% by weight of diethylene glycol monobutyl ether as an organic solvent The monomer mixture was obtained.

The obtained monomer mixture was bubbled with nitrogen gas for 20 minutes to remove dissolved oxygen, and then the temperature inside the separable flask system was replaced with nitrogen gas and heated until the hot water bath boiled with stirring. An ethyl acetate solution of a polymerization initiator was added, and further an ethyl acetate solution of a polymerization initiator was added several times during the polymerization.

Seven hours after the start of polymerization, the polymerization was terminated by cooling to room temperature. This obtained the diethylene glycol monobutyl ether solution of the polymethylmethacrylate (PMMA) which has a carboxyl group at the terminal. The obtained (meth) acrylic resin was analyzed by gel permeation chromatography using a column LF-804 manufactured by SHOKO as a column, and the number average molecular weight in terms of polystyrene was as shown in Table 5.
To the diethylene glycol monobutyl ether solution of polymethyl methacrylate thus obtained, diethylene glycol monobutyl ether was further added so as to have the composition ratio shown in Table 5, and dispersed with a high-speed disperser to produce a binder resin composition. did.

0.2% by weight of polyoxyethylene sorbitan monostearate (“Nonion ST221” manufactured by NOF Co., Ltd.) as a surfactant and 2- (8-heptadecenyl) — as a dispersant with respect to the obtained binder resin composition 2-Imidazoline-1-ethanol was added to 0.3 wt%. (Y, Gd) BO ₃ : Eu (red phosphor) is added as a phosphor so as to have the composition ratio shown in Table 5, sufficiently kneaded using a high-speed stirrer, and smooth in a three-roll mill. The mixture was kneaded until it reached a phosphor paste composition.

(Examples 20 and 21, Comparative Examples 12 to 17)
A binder resin composition and a phosphor paste composition were produced in the same manner as in Example 19 except that each component was adjusted to have the composition ratio described in Table 5 or Table 6.

(Evaluation)
The phosphor paste compositions prepared in Examples 19 to 21 and Comparative Examples 12 to 17 were evaluated by the following methods.
The results are shown in Table 7.

(1) Storage stability (Viscosity change rate (%))
The phosphor paste composition immediately after dispersing the phosphor is put in a 250 ml polyethylene container, and the fluorescence is measured using a B-type viscometer (“DVII + Pro” manufactured by BROOK FILED) at a temperature of 23 ° C. and a rotation speed of 10 rpm. The viscosity η ^A _{10 rpm} (Pa · s) of the body paste composition was measured. Thereafter, the phosphor paste composition placed in a polyethylene container was stored for 1 month in an environment of a temperature of 23 ° C. and a humidity of 50%, and then again using a B-type viscometer under the conditions of a temperature of 23 ° C. and a rotation speed of 10 rpm. Then, the viscosity η ^B _{10 rpm} (Pa · s) of the stored phosphor paste composition was measured, and the viscosity change rate (%) was calculated.
Viscosity change rate (%) was calculated by the following formula.
Viscosity change rate (%) = [(η ^A _{10 rpm−} η ^B _{10 rpm} ) / η ^A _{10 rpm} ] × 100

(2) Storage stability (presence or absence of precipitate)
The phosphor paste composition immediately after the phosphor was dispersed was placed in a 250 ml polyethylene container, and it was visually observed whether or not a precipitate was present at the bottom of the container. Thereafter, the phosphor paste composition placed in a polyethylene container was stored for one month in an environment of a temperature of 23 ° C. and a humidity of 50%, and then it was visually observed again whether a precipitate was present at the bottom of the container.
The following criteria were used to evaluate whether sediment was present at the bottom of the container.
○: No precipitate was observed at the bottom of the container.
X: A precipitate was observed at the bottom of the container.

(3) The phosphor paste composition immediately after the screen-printing phosphor was dispersed was put in a 250 ml polyethylene container and stored for 1 month in an environment of a temperature of 23 ° C. and a humidity of 50%. Next, screen printing was performed using the stored phosphor paste composition in an environment of a temperature of 23 ° C. and a humidity of 50%.
For screen printing, a screen printing machine ("MT-320TV" manufactured by Microtech Co., Ltd.), screen plate making ("SX230 ° B" manufactured by Tokyo Process Service Co., Ltd. (emulsion 20 μm, screen frame 320 mm x 320 mm)), printing substrate (soda glass) 150 mm × 150 mm, thickness 15 mm), and screen printing was performed under the conditions of the following screen printer.
Gap: 2.0mm
Squeegee speed: 50 mm / s
Scraper speed: 50mm / s
Squeegee pressure: 0.25 MPa
Scraper pressure: 0.17 MPa
Back pressure: 0.10 MPa

FIG. 1 shows an aspect of screen printing. A print pattern 1 shown in FIG. 1 is a print pattern formed in the horizontal direction with respect to the moving direction of the squeegee. A print pattern 2 shown in FIG. 1 is a print pattern formed in a 45 ° oblique direction with respect to the moving direction of the squeegee.
With respect to the print pattern 1 and the print pattern 2 shown in FIG. 1, screen printability was evaluated according to the following criteria.
○: No fading was observed in the print pattern.
X: The print pattern was faint or could not be printed.

(Example 22)
In a 2 L separatory flask equipped with a stirrer, cooler, thermometer, and nitrogen gas inlet, 100 parts by weight of methyl methacrylate (Mitsubishi Rayon Co., Ltd.) and mercaptosuccinic acid (manufactured by Wako Pure Chemical Industries, Ltd.) as a chain transfer agent 1.5 parts by weight and 100 parts by weight of texanol (manufactured by Kyowa Hakko Chemical Co., Ltd.) as an organic solvent were mixed to obtain a monomer mixture.

The obtained monomer mixture is bubbled with nitrogen gas for 20 minutes to remove dissolved oxygen, and then the temperature inside the separable flask system is replaced with nitrogen gas and stirred until the solution temperature reaches 95 ° C. did. After the temperature reached, a solution of the polymerization initiator diluted with ethyl acetate was added. During the polymerization, an ethyl acetate solution containing a polymerization initiator was added several times.
Ten hours after the start of polymerization, the polymerization was terminated by cooling to room temperature. Thereby, a texanol solution of polymethyl methacrylate (PMMA) was obtained as a (meth) acrylic resin.
When the obtained (meth) acrylic resin was analyzed by GPC, the weight average molecular weight in terms of polystyrene was 5000. In addition, the column LF-804 made from SHOKO was used for the measurement of the polystyrene conversion weight average molecular weight as a column.

Binder resin containing 39.7% by weight of tertexanol with respect to 25% by weight of polymethyl methacrylate by further adding texanol to the obtained polymethyl methacrylate solution and dispersing using a high-speed disperser. A composition was obtained.
With respect to the obtained binder resin composition, 0.2% by weight of polyoxyethylene (POE) (20) sorbitan monolaurate (“Reodol TW-L120” manufactured by Kao Co., Ltd.) as a surfactant, and poly as a dispersant. Add 0.1% by weight of carboxylic acid (manufactured by Enomoto Kasei Co., Ltd., “Disparon 2150”) and 35% by weight of green phosphor powder (manufactured by Nichia Chemical Co., Ltd., Zn ₂ SiO ₄ : Mn). By using and kneading sufficiently, a phosphor paste composition was prepared.

(Examples 23 to 25)
A binder resin composition and a phosphor paste composition were produced in the same manner as in Example 22 except that each component was adjusted to have the composition ratio described in Table 8.

(Comparative Examples 18 and 19)
A binder resin composition and a phosphor paste composition were produced in the same manner as in Example 22 except that each component was adjusted to have the composition ratio described in Table 8.

<Evaluation>
The phosphor paste compositions obtained in Examples 22 to 25 and Comparative Examples 18 and 19 were evaluated as follows. The results are shown in Table 9.

(1) Viscosity evaluation The obtained phosphor paste composition was subjected to a viscosity of the phosphor paste composition using a B-type viscometer (“DVII + Pro” manufactured by BROOK FIELD, Inc.) at a temperature of 23 ° C. and a rotation speed of 10 rpm. η _{10 rpm} (Pa · s) was measured.

(2) Evaluation of surface roughness The obtained phosphor paste composition was applied to a slide glass (2 cm × 5 cm) to a thickness of 12.5 μm. After the slide glass coated with the phosphor paste composition was dried at 120 ° C. for 10 minutes, the surface of the phosphor paste composition coated with a surface roughness meter (“Surfcoder SE-30D” manufactured by Kosaka Laboratory Ltd.) was measured. did. The surface roughness Ra was evaluated according to the following criteria.
○: Ra = less than 1.0 μm ×: Ra = 1.0 μm or more

(3) Dispersibility evaluation The obtained phosphor paste composition was measured with a grind gauge (Ericsson, 0 to 15 μm) to measure the distribution density of the phosphor, and the scale where the aggregated phosphor appeared was observed. . However, the measurement was performed 5 times, and the average value of the scales at the places where the phosphor aggregated in 10 lines appeared was evaluated. Dispersibility was evaluated according to the following criteria.
○: Less than 10 μm ×: 10 μm or more

(4) Screen printing Screen printing was performed on the obtained phosphor paste composition in an environment of a temperature of 23 ° C. and a humidity of 50%.
For screen printing, a screen printing machine ("MT-320TV" manufactured by Microtech Co., Ltd.), screen plate making ("SX230 ° B" manufactured by Tokyo Process Service Co., Ltd. (emulsion 20 μm, screen frame 320 mm x 320 mm)), printing substrate (soda glass) 150 mm × 150 mm, thickness 15 mm), and screen printing was performed under the conditions of the following screen printer.
Gap: 2.0mm
Squeegee speed: 50 mm / s
Scraper speed: 50mm / s
Squeegee pressure: 0.25 MPa
Scraper pressure: 0.17 MPa
Back pressure: 0.10 MPa
The obtained printed image was evaluated by visual observation with a stereomicroscope.
A: There is no variation in the thickness of the printed image, the printed image is sufficiently thick, and the density is high. O: There is no variation in the thickness of the printed image. Δ: There is no variation in the thickness of the printed image, but the printed image is very large. ×: There is variation in the thickness of the printed image

ADVANTAGE OF THE INVENTION According to this invention, the phosphor paste composition which can be printed by screen printing, has the favorable dispersibility of a fluorescent substance, is excellent in storage stability, and can be degreased at low temperature can be provided.

It is a schematic diagram which shows an example of the aspect of screen printing.

Claims (14)

A phosphor paste composition containing (meth) acrylic resin, phosphor, organic solvent, polyoxyethylene sorbitan fatty acid ester having an HLB value of 9 or more,
A phosphor paste composition having a viscosity of 8 to 40 Pa · s when measured at 23 ° C. using a B-type viscometer with a probe rotation speed set to 10 rpm. The polyoxyethylene sorbitan fatty acid ester is a compound represented by the following chemical formula (1) and / or a compound represented by the following chemical formula (2), or a compound represented by the following chemical formula (3): The phosphor paste composition according to claim 1.

R ¹ , R ² and R ³ are C _n H _2n-1 or C _n H _{2n + 1} (n is an integer of 5 or more), and a + b + c = 20, d + e + f = 20, and g + h + i + j = 20. The phosphor paste composition according to claim 1 or 2, wherein the (meth) acrylic resin has a weight average molecular weight of 5000 to 50,000 in terms of polystyrene. The phosphor paste composition according to claim 1, 2 or 3, wherein the (meth) acrylic resin has a polar group at the end of the molecular chain. The phosphor paste composition according to claim 4, wherein the polar group is a hydrogen bonding functional group. The phosphor paste composition according to claim 1, 2, 3, 4 or 5, wherein the (meth) acrylic resin is polymethyl methacrylate. The phosphor paste composition according to claim 1, 2, 3, 4, 5 or 6, wherein the content of the (meth) acrylic resin is 5 to 25% by weight. Furthermore, the fluorescent substance paste composition of Claim 1, 2, 3, 4, 5, 6 or 7 containing the organic compound which has 3 or more of hydroxyl groups as a dispersing agent. The phosphor paste composition according to claim 8, wherein the organic compound having three or more hydroxyl groups is glycerin. The phosphor paste composition according to claim 1, 2, 3, 4, 5, 6 or 7, further comprising an organic compound having three or more carboxyl groups as a dispersant. Furthermore, polyether ester acid amine salt is contained as a dispersing agent, The fluorescent substance paste composition of Claim 1, 2, 3, 4, 5, 6 or 7 characterized by the above-mentioned. The phosphor paste composition according to claim 8, 9, 10 or 11, wherein the content of the dispersant is 0.1 to 5% by weight. The phosphor according to claim 1, further comprising a polyoxyethylene alkyl ether having an HLB value of 11 or more. Paste composition. Furthermore, an imidazole compound represented by the following chemical formula (6) or the following chemical formula (7) is contained, characterized in that: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 12. A phosphor paste composition according to 12 or 13.

R ⁴ represents C _n H _{2n + 1} (n is an integer of 5 or more) or C _n H _2n-1 (n is an integer of 5 or more), and R ⁵ represents H, C _n H _{2n + 1} (n Represents an integer of 1 to 5) or C _n H _2n OH (n is an integer of 1 to 5), R ⁶ is H, C _n H _{2n + 1} (n is an integer of 1 to 5), Alternatively, C _n H _2n OH (n is an integer of 1 to 5), R ⁷ is H or C _n H _{2n + 1} (n is an integer of 1 to 5).

R ⁸ represents C _n H _{2n + 1} (n is an integer of 5 or more) or C _n H _2n-1 (n is an integer of 5 or more), and R ⁹ represents H, C _n H _{2n + 1} (n Represents an integer of 1 to 5) or C _n H _2n OH (n is an integer of 1 to 5), R ¹⁰ is H, C _n H _{2n + 1} (n is an integer of 1 to 5), _or, (the n, 1 to 5 integer) C _n H 2n OH ^{indicates, R 11} is, H, _or, (the n, 1 to 5 integer) C _{n H 2n +} 1 illustrates a.

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