KR20100038360A - Phosphor paste composition - Google Patents

Abstract

It is intended to provide a phosphor paste composition, which is capable of printing by screen printing, has good phosphor dispersibility, is excellent in storage stability and can be degreased at a low temperature. The invention is directed to the phosphor paste composition containing a (meth)acrylic resin, a phosphor, an organic solvent and a polyoxyethylenesorbitan fatty acid ester having an HLB value of 9 or more, wherein a viscosity when measured by setting a probe revolution at 23°C using a B-type viscometer to 10 rpm is 8 to 40 Pa·s.

Description

Phosphor Paste Composition {PHOSPHOR PASTE COMPOSITION}

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

In recent years, the inorganic fine particle paste composition which disperse | distributed inorganic fine particles, such as electroconductive powder and ceramic powder, to binder resin is used in order to obtain the sintered compact of various shapes. In particular, phosphor paste compositions in which phosphors are dispersed in binder resins as inorganic fine particles are used in organic EL and the like, and demand is increasing in recent years.

The phosphor paste composition can be formed into a sintered body of a required shape by, for example, being processed into a predetermined shape by screen printing, a coating method using a doctor blade, a casting method for processing into a sheet shape, or the like. Among them, screen printing is particularly suitable for mass production.

It is preferable that the fluorescent paste composition used for screen printing has thixotropy. Thixotropy is a property that viscosity is low when rotation speed is high (displacement with high deformation rate), for example, and viscosity is high when rotation speed is low (displacement with low deformation speed) when rotational viscosity is evaluated. . When the phosphor paste composition is sufficiently low in viscosity at the time of application | coating, application | coating is easy, On the other hand, when it is left to stand after application | coating, a viscosity is high enough and the property which is not cast by self weight is calculated | required.

As binder resin used for a fluorescent paste composition, it is common to use cellulose resins, such as ethyl cellulose which has thixotropy. However, the phosphor paste composition in which the phosphor is dispersed in the cellulose resin is not thermally decomposed unless fired at a high temperature. Therefore, a large energy is required in the production process, there is a problem such as a long firing time.

The method of using the acrylic resin which can be degreased at low temperature compared with cellulose resin is examined about such a problem. For example, Patent Document 1 discloses a phosphor paste composition using an acrylic resin.

However, such a phosphor paste composition exhibits very strong adhesiveness attributable to an acrylic resin, and when screen printing is performed, twisted yarns occur on the screen printing plate, which makes handling difficult during screen printing. Moreover, compared with the case where the cellulose resin with low adhesiveness was used, the printed image might become thin. In addition, it was necessary to wash the screen printing plate for a long time in order to remove the acrylic resin. Although the adhesiveness can be reduced by reducing the addition amount of the acrylic resin, the viscosity of the phosphor paste composition is remarkably lowered accordingly, so that dispersing the phosphor having a high specific gravity causes the phosphor to settle or aggregate, so-called "storage stability" becomes worse. Had a problem.

Therefore, the method of reducing the addition amount of acrylic resin, raising the viscosity of fluorescent substance paste composition, and maintaining storage stability was also considered by making molecular weight of acrylic resin large. However, when the molecular weight of acrylic resin was raised, there existed a problem that a continuous twist occurred violently and screen printing became difficult.

For such a problem, for example, Patent Literature 2 discloses a method of adding thixotropic agents such as fatty acid amide, hydrogenated castor oil, and polyamino acid in a phosphor paste composition. However, all of these thixotropic agents were additives for increasing the viscosity of the phosphor paste composition and were not sufficient to obtain a phosphor paste composition suitable for screen printing. In addition, the thermal decomposition property of the phosphor paste composition was deteriorated, and there was also a problem that a residue remained.

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 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 potential of the surface or to deactivate the hydrogen bonding site, thereby suppressing aggregation by the steric effect of the portion other than the carboxyl group, It is disclosed that the dispersibility is improved. However, with this method, it is difficult to maintain long-term storage stability, and the phosphor may settle or aggregate. In addition, the phosphor paste composition having a low viscosity was remarkable in viscosity change, making it difficult to obtain a phosphor paste composition suitable for screen printing.

In patent document 4, in order to improve the dispersibility of fluorescent substance, the method of adding the nonionic surfactant which consists of a compound containing hydroxyalkyl groups, such as bis (2-hydroxyethyl) alkylamine, and a nitrogen atom, to a fluorescent paste composition is mentioned. Is disclosed.

However, since the phosphor paste composition disclosed in the Example of patent document 3 has a viscosity of 4.4-5.0 Pa.s, the phosphor immediately after dispersion shows good dispersibility, but it may settle as time passes. there was. In addition, the thermal decomposition property of the phosphor paste composition was deteriorated, and there was a problem that a residue remained.

As described above, it was very difficult to improve the screen printability by reducing the adhesiveness of the phosphor paste composition while securing the dispersibility of the phosphor.

Japanese Patent Application Laid-Open No. 9-012979 Japanese Unexamined Patent Publication No. 2000-144124 Japanese Unexamined Patent Publication No. 2003-257314 Japanese Laid-Open Patent Publication 2003-292947

In view of the above-described phenomenon, an object of the present invention is to provide a phosphor paste composition which can be printed by screen printing, has a good dispersibility of phosphors, excellent storage stability, and can be degreased at low temperatures.

The present invention relates to 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, wherein the probe rotation speed is 10 rpm using a type B viscometer at 23 ° C. It is a phosphor paste composition whose viscosity when it sets and measures is 8-40 Pa.s.

The present invention is described in detail below.

The present inventors use a (meth) acrylic resin as a binder resin in the screen design of the phosphor paste for screen printing, and by reducing the addition amount of the (meth) acrylic resin, it is possible to perform degreasing at a low temperature of the phosphor paste composition, Improvements in storage stability have been considered. However, only by adjusting the viscosity by reducing the amount of acrylic resin added, there was a problem of poor screen printability and poor storage stability due to precipitation or aggregation of the phosphor. Therefore, the present inventors studied further, and as a result, screen-printability was performed by adjusting the viscosity of a fluorescent substance paste composition using (meth) acrylic resin as a binder resin, and polyoxyethylene sorbitan fatty acid ester of a specific structure as surfactant. It was found that the phosphor paste composition that was excellent in storage stability and that could be degreased at low temperature was obtained, and thus, the present invention was completed.

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 this invention contains a (meth) acrylic resin. The (meth) acrylic resin has a role as a binder.

Although it will not specifically limit, if it is a (meth) acrylic resin which can be degreased at low temperature (400 degrees C or less) as said (meth) acrylic resin, For example, methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (Meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Homopolymer of (meth) acrylate monomers, such as isobornyl (meth) acrylate, n-stearyl (meth) acrylate, and benzyl (meth) acrylate, the said (meth) acrylate monomer, and a polypropylene oxide And copolymers of (meth) acrylate monomers having a polyoxyalkylene structure such as polymethylethylene oxide, polyethylethylene oxide, polytrimethylene oxide, and polytetramethylene oxide can be used. . Here, for example, (meth) acrylate means acrylate or methacrylate.

Especially, since the viscosity of the fluorescent substance paste composition suitable for screen printing property can be obtained, reducing the content of (meth) acrylic resin, methyl methacrylate which is high in glass transition temperature (Tg) and can be degreased at low temperature. It is preferable to contain a monomer as a polymer component, and polymethyl methacrylate which is a homopolymer of a methyl methacrylate monomer especially is preferable.

It is preferable that the said (meth) acrylic resin has a polar group in the molecular chain terminal. Thereby, printability improves and it can print more preferably for screen printing.

When the 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 is extremely low, and it is necessary to add more resin to maintain the viscosity. As a result, since adhesiveness becomes high, a crack may appear in a printed pattern, or printing may become impossible.

Since the polar group is present at the terminal of the molecular chain instead of the side chain, the (meth) acrylic resin and the organic solvent are incompatible and exhibit suitable phase separation (micro phase separation), which is required for printing with low molecular weight and low resin content. The viscosity can be secured. As a result, since the adhesiveness of the fluorescent substance paste composition is small and it is hard to generate | occur | produce twisted yarn, print handleability becomes favorable.

Among them, even when the phosphor paste composition stored for a long time is used, a good printing pattern can be obtained, and in view of excellent storage stability, the polar group does not exist in the molecular side chain of the (meth) acrylic resin, It is preferable to use an acrylic resin.

It is preferable that the said polar group is a hydrogen bondable functional group especially.

It does not specifically limit as said hydrogen bond functional group, For example, a hydroxyl group, a carboxyl group, an amino group, a polyoxyalkylene ether group, etc. are mentioned. Especially, a hydroxyl group and a carboxyl group are preferable for the reason that a (meth) acrylic resin can be thermally decomposed at low temperature without a residue.

In addition, the hydrogen-bonding functional group may have at least one. However, the phase separation structure is stabilized as the number thereof increases, and the adhesiveness of the phosphor paste composition is lowered. Thus, screen printing is improved without the occurrence of continuous firing, which is effective.

As a method of introducing a polar group into the molecular chain terminal of the said (meth) acrylic resin, Specifically, for example, in the presence of the chain transfer agent which has a polar group, the (meth) acrylate monomer mentioned above is pre-radical polymerization method, The method of superposing | polymerizing or copolymerizing by conventionally well-known methods, such as a living radical polymerization method, an inipher polymerization method, an anion polymerization method, a living anion polymerization method, is mentioned.

Moreover, a polar group can be introduce | transduced into a (meth) acryl molecule chain terminal also by using superposition | polymerization initiators, such as an organic peroxide initiator and an azo initiator which have a polar group.

The introduction of the polar group into the molecular chain terminal of the (meth) acrylic resin can be confirmed by, for example, ¹³ C-NMR.

Especially as a chain transfer agent which has the said polar group, the chain transfer agent which has a hydrogen bond functional group is preferable, For example, it has a carboxyl group as mercaptopropanediol, thioglycerol, and a hydrogen bond functional group which have a hydroxyl group as a hydrogen bond functional group. Mercapto succinic acid, mercaptoacetic acid, the amino ethane thiol which has an amino group as a hydrogen bond functional group, etc. are mentioned.

Especially as an organic peroxide initiator which has the said polar group, the organic peroxide initiator which has a hydrogen bond functional group is especially preferable, For example, P-mentan hydroperoxide ("Pamenta H" by Nichiyu Co., Ltd.), diisopropyl benzene hydro Peroxide ("Park mill P" by Nichiyu Corporation), 1,2,3,3-tetramethylbutyl hydroperoxide ("Perocta H" by Nichiyu Corporation), cumene hydroperoxide (Park Mill H by Nichiyu Corporation) -80 "), t-butyl hydroperoxide (" Perbutyl H-69 "by Nichiyu Corporation), cyclohexanone peroxide (" Perhexa H "by Nichiyu Corporation), 1,1,3,3-tetramethylbutyl Hydroperoxide, t-butyl hydroperoxide, t-amyl hydroperoxide, Disuccinic acid peroxide (perroyl SA), and the like.

Especially as an azo initiator which has the said polar group, the azo initiator which has a hydrogen bond functional group is preferable, For example, 2,2'- azobis [N- (2carboxyethyl) -2-methylpropionamidine ] The polymerization initiator which has many hydroxyl groups and a carboxyl group like hydrate or 2,2'- azobis {2-methyl-N-1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide 하게 is preferable. Can be used.

The minimum with 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 said weight average molecular weight is less than 5000, since the (meth) acrylic resin and the organic solvent cannot express suitable phase separation (micro phase separation), the viscosity required for screen printing may not be obtained. The minimum with more preferable said weight average molecular weight is 10000. When the said weight average molecular weight exceeds 50000, since the twistability of a fluorescent substance paste composition becomes high, it may become easy to generate | occur | produce, and screen printability may deteriorate. The upper limit with more preferable weight average molecular weight is 40000, and a more preferable upper limit is 30000. In particular, when the weight average molecular weight of the said (meth) acrylic resin is 10000-30000, since a clear image is obtained at the time of screen printing, it is preferable.

In the conventional phosphor paste composition, in order to maintain the viscosity which can be screen-printed, the (meth) acrylic resin of comparatively high molecular weight was used. In contrast, in the phosphor paste composition of the present invention, even when a (meth) acrylic resin having a weight average molecular weight in the range of 5000 to 50000 is used by appropriate phase separation (micro phase separation), good screen printability can be exhibited.

In addition, the measurement of the weight average molecular weight by polystyrene conversion can be obtained by GPC measurement using the column LF-804 by SHOKO company, for example as a column.

Although it does not specifically limit as molecular weight distribution (weight average molecular weight / number average molecular weight = Mw / Mn) of the said (meth) acrylic resin, A preferable upper limit is 3. When the molecular weight distribution exceeds 3, the monomer, oligomer, or the like, which is a low molecular weight component, acts as a plasticizer, where sufficient viscosity is not obtained in the phosphor paste composition, or by containing a high molecular weight component, May occur, and a problem may occur during screen printing. The upper limit with more preferable 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 content of the said (meth) acrylic resin is less than 5 weight%, the fluorescent substance paste composition of the viscosity suitable for screen printing may not be obtained. When the content of the (meth) acrylic resin is more than 25% by weight, the viscosity of the phosphor paste composition is too high, making screen printing difficult, or the adhesiveness becomes strong, and thus, there may be cases in which easy yarn occurs during screen printing. .

Moreover, when using as a binder resin used for the fluorescent substance paste composition of this invention without refine | purifying the (meth) acrylic resin after a polymerization reaction, it is preferable that the monomer paste, an oligomer, etc. which are low molecular weight components are not contained in a fluorescent substance paste composition. Do. When monomer, oligomer, etc. which are low molecular weight components are contained in a fluorescent paste composition, a monomer, an oligomer, etc. may act as a plasticizer and may reduce a viscosity.

The phosphor paste composition of this invention contains the polyoxyethylene sorbitan fatty acid ester whose HLB value is 9 or more.

Conventionally, in the fluorescent paste composition, when (meth) acrylic resin is used as binder resin, in order to improve the dispersibility and screen printability of fluorescent substance, using various dispersing agents, surfactant, etc. has been examined. Particularly, in the phosphor paste composition having a low viscosity, the dispersibility and the screen printability of the phosphor cannot be sufficiently secured, and the dispersibility and the screen printability may be remarkably lowered depending on the kind of the phosphor to be used.

In the present invention, by using such a polyoxyethylene sorbitan fatty acid ester as a surfactant, dispersibility and screen printability can be remarkably improved without depending on the composition of the phosphor and without impairing the degreasing property of the binder. .

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 dispersibility and screen printability of the phosphor 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 is lowered.

When the said polyoxyethylene sorbitan fatty acid ester is contained, the dispersibility of fluorescent substance will become favorable, but the viscosity of fluorescent substance paste composition may become low. 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 lowering the viscosity of the phosphor paste composition. Moreover, the minimum with preferable HLB value is 9.5, and a preferable upper limit is 17.0.

Here, the said HLB value is an index which shows the balance of the hydrophilicity or lipophilic property of surfactant, The closer to 0, the higher lipophilic property, The closer to 20, the more hydrophilic property becomes high. In addition, the said HLB value is a formula of the following griffin, for example

[(Molecular weight of hydrophilic part) ÷ total molecular weight) × 100] / 5

Is a value calculated using.

Moreover, it is preferable that the said polyoxyethylene sorbitan fatty acid ester is a compound represented by following formula (1) and / or a compound represented by following formula (2), or a compound represented by following formula (3).

[Formula 1]

[Formula 2]

[Formula 3]

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

In the above general formula [R ^1, R ² and R ³ is a 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 said polyoxyethylene sorbitan fatty acid ester does not play a role as surfactant, and the dispersibility of fluorescent substance in fluorescent substance paste composition may fall, or screen printability may fall.

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.

In addition, 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.

In addition, g + h + i + j = 20 means that g, h, i, and j are each an integer greater than or equal to 1, and the sum total of g, h, i, and j becomes 20.

As a polyoxyethylene sorbitan fatty acid ester represented by the said General formula (1) and / or the said General formula (2), for example, polyoxyethylene (20) sorbitan monolaurate (Cao Corporation "Leodor TW-L120 "HLB value 16.7), polyoxyethylene (20) sorbitan monostearate (" Leodore TW-S120V "made by Kao Corporation HLB value 10.5), polyoxyethylene (20) sorbitan monooleate (" Leo manufactured by Kao Corporation) DOR TW-O120V "HLB value 15), polyoxyethylene (20) sorbitan monopalmitate (" Leodore TW-P120 "HLB value 15.6 by Kao Corporation), etc. are mentioned.

As polyoxyethylene sorbitan fatty acid ester represented by the said General formula (3), For example, polyoxyethylene sorbitan mono palm fatty acid ester ("Sorgen TW-20" HLB value 16.7 by Daiichi Kogyo Pharmaceutical Co., Ltd.), polyoxy Ethylene sorbitan monostearate ("Sorgen TW-60" HLB value 14.9 made by Daiichi Kogyo Pharmaceutical Co., Ltd.), polyoxyethylene sorbitan monooleate ("Sorgen TW-80" HLB value 15 made by Daiichi Kogyo Pharmaceutical Co., Ltd.), etc. 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 content of the said polyoxyethylene sorbitan fatty acid ester is less than 0.01 weight%, the effect which raises the dispersibility of fluorescent substance paste composition, and the effect which improves screen printability may not be expressed. When content of the said polyoxyethylene sorbitan fatty acid ester exceeds 5 weight%, the viscosity of a fluorescent substance paste composition may fall and 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, the phosphor paste composition of the present invention, in order to stabilize a suitable 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, thereby further excellent phosphor print paste A composition can be obtained. The polyoxyethylene alkyl ether having the 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.

It is preferable that the fluorescent substance paste composition of this invention contains the nonionic surfactant whose HLB value is 10 or more combined with the said polyoxyethylene sorbitan fatty acid ester. The nonionic surfactant having an HLB value of 10 or more is not particularly limited, but nonionic surfactants in which alkylene ether is added to the fatty chain are preferable, and specific examples thereof include polyoxyethylene lauryl ether and polyoxy. Ethylene cetyl ether and the like are preferably used. In addition, although the nonionic surfactant has good thermal decomposability, when it is added in a large amount, the nonionic surfactant in the phosphor paste composition may increase the thermal decomposition temperature of the phosphor paste composition or may cause residue. The upper limit with preferable content of is 5 weight%.

The phosphor paste composition of the present invention contains a phosphor.

It does not specifically limit as said fluorescent substance, For example, fluorescent substance used for various uses, such as fluorescent substance for CRT, fluorescent substance for lamps, fluorescent substance for PDP, fluorescent substance for X-rays, and photoluminescent fluorescent substance, is mentioned. 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 ： Ru phosphors such as Eu, 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, Gd ₂ O ₂ S: Green phosphors such as 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: there may be mentioned Sb, white phosphor such as Mn: Eu, etc. of the blue phosphor, Sr ₄ Al ₁₄ O _25: cyan fluorescent substance such as _{Eu, Dy, Ca 10 (PO} 4) 6 FCl.

In the phosphor paste composition of the present invention, among them, in terms of excellent dispersibility, blue phosphors such as BaMgAl ₁₀ O ₁₇ : Eu, green phosphors such as Zn ₂ SiO ₄ : Mn, and (Y, Gd) BO ₃ : The effect of this invention can fully be exhibited when using red fluorescent substance, such as Eu. In particular, further excellent dispersibility can be ensured by using glycerin, polycarboxylic acid, and polyether ester amine salt as dispersants as described later.

The fluorescent substance paste composition of this invention can be used suitably also when containing the said red fluorescent substance.

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 tends to settle and storage stability was not sufficient. On the other hand, in the phosphor paste composition of the present invention, when the imidazole compound described later is added, even when the red phosphor is contained, the red phosphor does not precipitate and is excellent in storage stability. This is considered to be because the said imidazole compound forms the structure which suppresses sedimentation of a red fluorescent substance.

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

The phosphor paste composition of the present invention contains an organic solvent.

It is preferable that the said organic solvent has at least 1 hydroxyl group or acetoxy group in a molecule | numerator. Thereby, it becomes easy to express the suitable phase separation (micro phase separation) of the (meth) acrylic resin and organic solvent which have a polar group in the said molecular chain terminal, and content of (meth) acrylic resin, maintaining the viscosity (thixotropy) suitable for screen printing. The degreasing at low temperature becomes easy.

Although it does not specifically limit as boiling point of the said organic solvent, A preferable minimum is 170 degreeC, and a preferable upper limit is 280 degreeC. If the boiling point of the said organic solvent is less than 170 degreeC, the organic solvent may volatilize during screen printing, and the working efficiency of screen printing may deteriorate, and when it exceeds 280 degreeC, the fluorescent paste composition of this invention can be degreased at low temperature. There may be no. The minimum with more preferable boiling point of the said organic solvent is 200 degreeC, and a more preferable upper limit is 250 degreeC.

It does not specifically limit as said organic solvent, 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 mono Isobutyl ether, trimethylpentanediol monoisobutylate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, terpineol, texanol, isophorone, butyl lactate, dioctylphthalate, dioctyl adipate, benzyl Alcohol, phenyl glycol phenyl propylene glycol, cresol, etc. are mentioned.

Among them, 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. Among them, diethylene glycol monoisobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, terpineol and texanol are particularly preferred, and in particular, diethylene glycol monobutyl ether and diethylene glycol monobutyl ether acetate , Terpineol and texanol are preferably used.

In addition, these organic solvents may be used independently and 2 or more types may be used together.

When the solubility parameter of the said (meth) acrylic resin is SP _M and the solubility parameter of the said organic solvent is SP _S , it is preferable that the said organic solvent satisfy | fills following formula (4) or following formula (5). .

Here, the solubility parameter (hereinafter also referred to as SP value) is a value estimated only by the chemical structure of the substance as described in Polymer Engineering & Science 14 147 (1974) and the like, and can be obtained by the following equation (5 '). have. Those with similar SP values are commonly used, and those with SP values farther are separated.

By the said organic solvent satisfy | filling following formula (4) or following formula (5), it becomes easy to express suitable phase separation (micro phase separation) of a (meth) acrylic resin and an organic solvent, and obtain a suitable viscosity (thixotropy) It becomes possible to become more excellent in screen printability.

Eｖ ： Evaporation energy (J / mol)

V: molar volume (㎥ / mol)

Δei: the evaporation energy of an atom or group of atoms (cal / mol)

ΔVi: molar volume (cm 3 / mol)

It is preferable that the fluorescent substance paste composition of this invention contains a dispersing agent.

As said dispersing agent, it is preferable to use the organic compound which has three or more hydroxyl groups, the organic compound which has three or more carboxyl groups, polyether ester acid amine salt, etc. according to the kind of fluorescent substance. 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, in order to ensure dispersibility of the phosphor, it is important to select a dispersant in accordance with the composition of the phosphor.

It does not specifically limit as an organic compound which has 3 or more of said hydroxyl groups, For example, polyols, such as glycerin, polypropylene glycol, polytetramethylene glycol, are mentioned.

-올레핀-무수 말레산 공중합체, 불포화 폴리카르복실산류, 지방족 다가 카르복실산류 등을 들 수 있다. It does not specifically limit as an organic compound which has 3 or more of said carbonyl groups, For example,

-Olefin-maleic anhydride copolymer, unsaturated polycarboxylic acid, aliphatic polyhydric carboxylic acid, etc. are mentioned.

These dispersants can realize excellent dispersibility even when a blue phosphor such as BaMgAl ₁₀ O ₁₇ : Eu is used as the phosphor of the low viscosity phosphor paste composition by the synergistic effect of the polyoxyethylene sorbitan fatty acid ester. In particular, when glycerin or a polyhydric carboxylic acid compound is used as the dispersant, a phosphor paste composition expressing very 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 content of the said dispersing agent is less than 0.1 weight%, the dispersion state of the fluorescent substance in a fluorescent paste composition cannot be maintained, and a problem may arise in storage stability by sedimenting or agglomeration of fluorescent substance. Even if content of the said dispersing agent exceeds 5 weight%, further storage stability may not be obtained or the thermal decomposition property of fluorescent substance paste composition may fall. The minimum with more preferable content of the organic compound which has 3 or more of said hydroxyl groups is 1 weight%, and a more preferable upper limit is 3 weight%.

It is preferable that the fluorescent substance paste composition of this invention contains the imidazole compound further represented by following General formula (6) or following General formula (7).

[Formula 4]

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 is H, C _n H _{2n + 1} (n is 1 to 5) Integer) 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), or C _n H _2n OH (n is represents an integer of 1-5), R ⁷ represents H, or C _n H _{2n +1 (n} is an integer of 1 to 5).

[Chemical Formula 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 is H, C _n H _{2n + 1} (n is 1 to 5 Integer) 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 C _n H _2n OH (n is represents an integer of 1-5), R ¹¹ is H, or C _n H _{2n +1 (n} represents an integer of 1 to 5).

In the present specification, the imidazole compound refers to the imidazoline compound (dihydroimidazole) represented by the general formula (6) and the imidazole compound represented by the general formula (7).

Especially, it is preferable that the fluorescent substance paste composition of this invention contains the imidazole compound represented by the said General formula (6).

In the general formula (6), R ⁴ is 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), but R ⁴ is C _n H that the structure represented by _{2n +1} (n is an integer between 5-30) or C _n H _{2n -1 (n} is an integer of 5-30) is preferred. If n is less than 5, the storage stability of the phosphor paste composition may not be obtained. If n is greater than 30, the chain length of the alkyl group or the alkenyl group is long. have.

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 more preferably a linear structure. Do. In the said General formula (6), when R <^4> is a linear structure, the fluorescent substance paste composition excellent in storage stability can be obtained.

In the formula (6), R ⁵ is not particularly limited as long as it 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). but, particularly preferably H or C ₂ H ₄ OH.

In the formula (6), R ⁶ is not particularly limited as long as it 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). However, in particular, H is preferable.

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

In the formula (7), R ⁸ is 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), but R ⁸ is C _n H _{2n +1} is preferably a structure represented by (n is an integer between 5-30) or C _n H _{2n -1} (n is an integer of 5-30). If n is less than 5, the storage stability of the phosphor paste composition may not be obtained. If n is greater than 30, the chain length of the alkyl or alkenyl group is long. have.

In addition, 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 more preferably a linear structure. In the formula (7), when R ⁸ is a linear structure, a phosphor paste composition having excellent storage stability can be obtained.

In the formula (7), R ⁹ is not particularly limited as long as it 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). but, particularly preferably H or C ₂ H ₄ OH.

In the formula (7), R ¹⁰ is not particularly limited as long as it 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). However, in particular, H is preferable.

In the general 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), but is particularly preferably H.

It does not specifically limit as a specific example of the said imidazole compound, As an imidazole compound represented by the said General formula (6), it is 2- (8-heptadecenyl) -2-imidazoline-1, for example. -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 is 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, R ⁷ And H). Especially, when 2- (8-heptadecenyl) -2-imidazoline-1-ethanol is used, since the fluorescent paste composition excellent in storage stability can be obtained, it can be used preferably.

Examples of the imidazole compound represented by the general 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-heptadecylimidazole (R ⁸ is C ₁₇ H ₃₅ , R ⁹ is H, R ¹⁰ is H, and R ¹¹ is H).

Although it does not specifically limit as content of the said imidazole 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%. If 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. If the content of the imidazole compound is more than 10% by weight, residues may be generated when fired at a low temperature. . The minimum with more preferable content of the said imidazole compound is 0.1 weight%, and a more preferable upper limit is 5 weight%.

The fluorescent substance paste composition of this invention is 8 Pa.s and an upper limit of 40 Pa.s when the probe rotation speed is set to 10 rpm and measured using a Brookfield viscometer at 23 degreeC. When the viscosity of the phosphor paste composition of the present invention is less than 8 Pa · s, the dispersion state of the phosphor in the phosphor paste composition cannot be maintained, and a problem may arise in storage stability due to precipitation or aggregation of the phosphor. Moreover, when the viscosity of the fluorescent substance paste composition of this invention exceeds 40 Pa * s, adhesiveness may become strong and printability may become difficult.

The method for producing the phosphor paste composition of the present invention is not particularly limited, and conventionally known methods can be cited. For example, each component is mixed using various mixers such as a ball mill, a blender mill, and three rolls. The method etc. are mentioned. Specifically, for example, the (meth) acrylic resin, the organic solvent, the dispersant, and the polyoxyethylene sorbitan fatty acid ester are mixed using a mixer to prepare a binder resin composition, and then the binder resin composition is The method of adding a fluorescent substance and mixing again using a mixer etc. is mentioned.

Since the fluorescent substance paste composition of this invention consists of the said structure, it can be screen-printed, it is excellent in storage stability, and can perform low temperature degreasing. Here, low temperature degreasing means that the degreasing temperature at which 99.5 weight% of the initial weight of a binder resin disappears is low temperature, and in this specification, degreasing temperature is 250-400 in normal air atmosphere which does not carry out nitrogen substitution. The case of ° C is defined as low temperature degreasing.

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

1 is a schematic diagram illustrating an example of a screen printing embodiment.

Although an Example is given to the following and this invention is demonstrated in more detail, this invention is not limited only to these Examples.

(Example 1)

100 parts by weight of methyl methacrylate monomer (MMA), a mercaptopropanediol as a chain transfer agent, and diethylene glycol mono as an organic solvent, in a 2 L separable plusk equipped with a stirrer, a cooler, a thermometer, a hot water bath and a nitrogen gas inlet. 100 weight part of butyl ethers were mixed, and the monomer liquid mixture was obtained.

After removing the dissolved oxygen by bubbling the obtained monomer liquid mixture for 20 minutes using nitrogen gas, the inside of the separable plusk system was replaced with nitrogen gas and heated up until the bath was boiled with stirring. Ethyl acetate solution of the polymerization initiator was added. In addition, an ethyl acetate solution of a polymerization initiator was added several times during the polymerization.

After 7 hours from the start of the polymerization, the mixture was cooled to room temperature and the polymerization was terminated. This obtained the diethylene glycol monobutyl ether solution of polymethyl methacrylate (PMMA) which has a hydroxyl group only in the molecular chain terminal. The obtained polymer was analyzed by gel permeation chromatography using SHOKO Co., Ltd. column LF-804 as a column. As a result, the weight average molecular weight (Mw) in terms of polystyrene was as shown in Table 1.

Thus, diethylene glycol monobutyl ether and polyoxyethylene (POE) (20) sorbitan monolaurate were used in the diethylene glycol monobutyl ether solution of polymethyl methacrylate obtained in this manner so as to have a composition ratio shown in Table 1. ("Leodore TW-L120" manufactured by Kao Corporation) was further added, and dispersed in 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 that it may become a composition ratio shown in Table 1, it knead | mixed sufficiently using a high speed stirring apparatus, it processed by three roll mills until it reached a smooth state, and fluorescent substance A paste composition was prepared.

(Examples 2 to 8)

By adjusting the addition amount using the chain transfer agent of Table 1, the polymethyl methacrylate which has the weight average molecular weight and terminal functional group of Table 1 was obtained. Then, the binder resin composition and the fluorescent substance paste composition were manufactured like Example 1 except having adjusted each component so that it might become the composition ratio of Table 1. Here, as surfactant, polyoxylauryl ether ("NIKKOL BL-25" by Nikko Chemicals), POE (20) sorbitan monostearate, POE (20) sorbitan monooleate, POE (20) Sorbitan monopalmitate, polyoxyethylene sorbitan mono palm fatty acid ester ("Sorgen TW-20" made by Daiichi Kogyo Pharmaceutical Co., Ltd.), polyoxyethylene sorbitan monostearate ("Sorgen TW-60 made from Daiichi Kogyo Pharmaceutical Co., Ltd.") ) And polyoxyethylene sorbitan monooleate ("Sorgen TW-80" manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) were used.

(Example 9)

100 parts by weight of methyl methacrylate (MMA), 3.8 parts by weight of mercaptosuccinic acid as a chain transfer agent, 2,2 as an organic solvent, to a 2 l separable plusk equipped with a stirrer, a cooler, a thermometer, a hot water bath and a nitrogen gas inlet. 100 parts by weight of, 4-trimethyl-1,3-pentanediol monoisobutylate (Texanol) was mixed to obtain a monomer mixture.

After removing the dissolved oxygen by bubbling the obtained monomer liquid mixture for 20 minutes using nitrogen gas, the inside of the separable plusk system was replaced with nitrogen gas and heated up until the bath was boiled with stirring. The ethyl acetate solution of the polymerization initiator was added, and the ethyl acetate solution of the polymerization initiator was added several times during the polymerization.

After 7 hours from the start of the polymerization, the mixture was cooled to room temperature and the polymerization was terminated. This obtained the 2,2,4-trimethyl-1,3-pentanediol monoisobutylate solution of polymethyl methacrylate (PMMA) which has a hydroxyl group at the terminal. The obtained (meth) acrylic resin was analyzed by gel permeation chromatography using SHOKO Co., Ltd. column LF-804 as a column, and the weight average molecular weight in terms of polystyrene was as shown in Table 1.

The 2,2,4-trimethyl-1, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate solution of the polymethyl methacrylate obtained as described above in order to have the composition ratio shown in Table 1, 3-pentanediol monoisobutylate, polyoxyethylene (POE) (20) sorbitan monolaurate ("Leodore TW-L120" by Kao Corporation) as a surfactant, and polyoxyethylene lauryl ether (Nikko Chemicals Co., Ltd.) Manufacture "NIKKOL BL-25") was further added, and it disperse | distributed with the high speed disperser, and produced the binder resin composition.

Of the resultant binder resin composition, ZnSiO ₄ as a phosphor: Mn (green phosphor) was added such that the composition ratio shown in Table 1, and sufficiently kneaded by a high speed agitator, kneading up to the three-roll mill to smooth state Thus, a phosphor paste composition was prepared.

(Example 10)

0.7 parts by weight of mercaptosuccinic acid to be used as a chain transfer agent to obtain polymethyl methacrylate, the content and interface of polymethyl methacrylate, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate A phosphor paste composition was produced in the same manner as in Example 9 except that the active agent was used as the composition shown in Table 1.

(Example 11)

-테르피네올과 부틸카르비톨아세테이트의 혼합 용제를 사용하여 계면활성제를 표 1 에 나타내는 조성으로 한 것 이외에는, 실시예 9 와 동일하게 하여 형광체 페이스트 조성물을 제조하였다. Of the composition shown in Table 1 as an organic solvent

A phosphor paste composition was prepared in the same manner as in Example 9 except that the surfactant was used as a composition shown in Table 1 using a mixed solvent of terpineol and butyl carbitol acetate.

(Example 12)

-테르피네올과 부틸카르비톨아세테이트의 혼합 용제를 사용하여 폴리메틸메타크릴레이트, 유기 용제, 계면활성제를 표 1 에 나타내는 조성으로 한 것 이외에는, 실시예 9 와 동일하게 하여 형광체 페이스트 조성물을 제조하였다. 0.7 parts by weight of mercaptosuccinic acid is used as the chain transfer agent, and the composition shown in Table 1 is used as the organic solvent.

A phosphor paste composition was prepared in the same manner as in Example 9 except that polymethyl methacrylate, an organic solvent, and a surfactant were used as the composition shown in Table 1 using a mixed solvent of terpineol and butyl carbitol acetate. .

(Comparative Example 1)

A phosphor paste composition was prepared in the same manner as in Example 1 except that no surfactant was added.

(Comparative Examples 2-4)

A phosphor paste composition was prepared in the same manner as in Example 1 except that the surfactants described in Table 1 were used.

(Comparative Example 5)

Except for using sorbitan monostearate ("Leodore SP-S10V" manufactured by Kao Corporation) and polyoxyethylene lauryl ether ("NIKKOL BL-4.2" manufactured by Nikko Chemicals) as a surfactant, it carried out similarly to Example 1 To prepare a phosphor paste composition.

(Comparative Example 6)

Except for using sorbitan tristearate ("Leodore SP-S30V" manufactured by Kao Corporation) and polyoxyethylene lauryl ether ("NIKKOL BL-2" manufactured by Nikko Chemicals) as a surfactant, it carried out similarly to Example 1 To prepare a phosphor paste composition.

<Evaluation>

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

(1) viscosity measurement

Using the obtained phosphor paste composition B-type viscometer (manufactured by BROOK FIELD "DⅦ + Pro"), temperature 23 ℃, under the conditions of a rotation number 10 rpm, the viscosity of the phosphor paste composition η _{10 rpm} (Pa · s) was measured.

(2) surface roughness evaluation

The obtained phosphor paste composition was applied to a slide glass (2 cm × 5 cm) so as to have a thickness of 12.5 μm. After drying the slide glass which apply | coated the phosphor paste composition for 10 minutes at 120 degreeC, the surface of the phosphor paste composition apply | coated with the surface roughness meter ("Surfcoder SE-30D" by Kosaka Research Institute) was measured. According to the following criteria, surface roughness Ra was evaluated.

○: Ra = less than 1.0 μm

X: Ra = 1.0 micrometer or more

(3) dispersibility evaluation

The distribution density of fluorescent substance was measured for the obtained fluorescent substance paste composition by the grind gauge (0-15 micrometers by Ericsson Corporation), and the scale of the point where the aggregated fluorescent substance appeared was observed. However, the measurement was performed 5 times and the average value of the scale of the point where the fluorescent substance aggregated in 10 lines appeared was evaluated. Dispersibility was evaluated according to the following criteria.

○: less than 10 μm

X: 10 micrometers or more

(4) screen printing

The obtained fluorescent substance paste composition was screen-printed in the environment of the temperature of 23 degreeC, and 50% of humidity.

For screen printing, screen printing machine ("MT-320TV" made by Microtec company), screen making ("SX230 degree B" (Tokyo Process Service company make) (oil 20 micrometers, screen frame 320mm * 320mm)), printed board (soda glass) 150 mm x 150 mm, thickness 15 mm) was screen-printed on condition of the following screen printing machines.

Gap: 2.0 mm

Squeegee speed: 50mm / 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 stereo microscope.

(Double-circle): There is no deviation in the thickness of a printed image, a printed image is thick enough, and its density is high.

○: There is no variation in the thickness of the print image

Δ: There is no variation in the thickness of the printed image, but the printed image is very thin

×: There is a variation in the thickness of the print image

(Example 13)

100 parts by weight of methyl methacrylate (MMA), mercaptopropanediol as a chain transfer agent, diethylene glycol monobutyl as an organic solvent, to a 2 l separable plusk equipped with a stirrer, a cooler, a thermometer, a hot water bath and a nitrogen gas inlet. 100 weight part of ethers were mixed and the monomer liquid mixture was obtained.

After removing the dissolved oxygen by bubbling the obtained monomer liquid mixture for 20 minutes using nitrogen gas, the inside of the separable plusk system was replaced with nitrogen gas and heated up until the bath was boiled with stirring. The ethyl acetate solution of the polymerization initiator was added, and the ethyl acetate solution of the polymerization initiator was added several times during the polymerization.

After 7 hours from the start of the polymerization, the mixture was cooled to room temperature and the polymerization was terminated. This obtained the diethylene glycol monobutyl ether solution of polymethyl methacrylate (PMMA) which has a hydroxyl group at the terminal. The obtained (meth) acrylic resin was analyzed by gel permeation chromatography using SHOKO Co., Ltd. column LF-804 as a column, and the weight average molecular weight in terms of polystyrene was as shown in Table 3.

Thus, diethylene glycol monobutyl ether, glycerin, and polyoxyethylene (POE) (20) sorbitan monolaurate were obtained so as to have a composition ratio shown in Table 3 with respect to the diethylene glycol monobutyl ether solution of polymethyl methacrylate thus obtained. Polyoxyethylene lauryl ether ("NIKKOL BL-25" by Nikko Chemicals Corporation) is further added as a rate ("Leodore TW-L120" by Cao Corp.) and nonionic surfactant, it is made to disperse | distribute with a high speed disperser, and binder resin The composition was prepared.

To the obtained binder resin composition, BaMgAl ₁₀ O ₁₇ : Eu (blue phosphor) was added as a phosphor so as to have a composition ratio shown in Table 3, and kneaded sufficiently using a high speed stirring device, and when it reached a smooth state with three roll mills. The mixture was kneaded to prepare a phosphor paste composition.

(Example 14, 15, 17, 18)

A phosphor paste composition was produced in the same manner as in Example 13 except that the (meth) acrylic resin, organic solvent, surfactant, and 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.

Then, polyoxyethylene (POE) (20) sorbitan monolaurate ("Leodore TW-L120" by Kao Corporation) and polyoxy as diethylene glycol monobutyl ether solution of obtained polymethyl methacrylate, surfactant The phosphor paste composition was produced like Example 13 except having used ethylene lauryl ether ("NIKKOL BL-25" by Nikko Chemicals).

(Comparative Examples 7-11)

A diethylene glycol monobutyl ether solution of polymethyl methacrylate was prepared in the same manner as in Example 13 using the chain transfer agent described in Table 3. Thereafter, a binder resin composition and a phosphor paste composition were prepared in the same manner as in Example 13 except that the components were adjusted to the composition ratios of Table 3.

Here, as a nonionic surfactant, polyoxyethylene lauryl ether ("NIKKOL BL-25" by Nikko Chemicals Corporation) was used, and the material described in Table 3 was used as a dispersing agent.

<Evaluation>

The following evaluation was performed about the binder resin composition and fluorescent substance paste composition obtained in Examples 13-18 and Comparative Examples 7-11. The results are shown in Table 4.

(1) viscosity evaluation

The viscosity (eta) _{10 rpm} (Pa * s) of the fluorescent substance paste composition was measured on the conditions of the temperature 23 degreeC and rotation amount 10rpm using the Brookfield viscometer ("D '+ Pro" by BROOK FIELD) of the obtained fluorescent paste composition.

(2) screen printability

The obtained phosphor paste composition was stored for 1 month in an environment of a temperature of 23 ° C. and a humidity of 50%. Subsequently, the obtained phosphor paste composition, a screen printing machine ("MT-320TV" manufactured by Microtec Co., Ltd.), screen making (20 µm of "SX230 ° B" manufactured by Tokyo Process Service, Inc., screen frame: 320 mm x 320 mm), printed board Using (soda-glass: 150 mm x 150 mm, thickness: 15 mm), it printed on the measurement conditions of the following screen printing machines in the environment of the temperature of 23 degreeC, and 50% of humidity.

Gap: 2.0 mm

Squeegee speed: 50mm / 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.

(Circle): A clean printing pattern was formed.

X: The print pattern had cracks or could not be printed.

(3) storage stability

After storing the obtained fluorescent substance paste composition for 1 month at 23 degreeC, the presence or absence of phase separation of a solution (liquid phase separation), sedimentation of fluorescent substance, etc. was visually confirmed and evaluated according to the following criteria.

(Circle): Phase separation of a solution (liquid phase separation), sedimentation of fluorescent substance, 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 decreased. Alternatively, the phosphor was precipitated at the bottom of the container to form a particle layer.

(4) Decomposition temperature measurement (TG-DTA evaluation (degreasing performance evaluation))

The obtained binder resin composition is heated to 600 degreeC by the temperature increase temperature of 10 degree-C / min in air atmosphere using a thermal decomposition apparatus ("simultaneousSDT2960 by TA Instruments company), and the thermal decomposition of 99.5 weight% of the initial weight of a binder resin composition is complete | finished The temperature was measured. Determination | settling property (circle) and binder resin composition which is 400 degreeC or more were judged as degreasing | degreasing | defatting property of the binder resin composition whose thermal decomposition end temperature is less than 400 degreeC.

      (Example 19)

100 parts by weight of methyl methacrylate (MMA), mercaptosuccinic acid as a chain transfer agent, diethylene glycol monobutyl ether as an organic solvent, to a 2 l separable plusk equipped with a stirrer, a cooler, a thermometer, a hot water bath and a nitrogen gas inlet. 100 weight part was mixed and the monomer liquid mixture was obtained.

After removing the dissolved oxygen by bubbling the obtained monomer liquid mixture for 20 minutes using nitrogen gas, the inside of the separable plusk system was replaced with nitrogen gas and heated up until the bath was boiled with stirring. The ethyl acetate solution of the polymerization initiator was added, and the ethyl acetate solution of the polymerization initiator was added several times during the polymerization.

After 7 hours from the start of the polymerization, the mixture was cooled to room temperature and the polymerization was terminated. This obtained the diethylene glycol monobutyl ether solution of polymethyl methacrylate (PMMA) which has a carboxyl group at the terminal. The obtained (meth) acrylic resin was analyzed by gel permeation chromatography using SHOKO Co., Ltd. column LF-804 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 a composition ratio shown in Table 5, and dispersed in a high speed disperser to prepare a binder resin composition. It was.

With respect to the obtained binder resin composition, 0.2 weight% of polyoxyethylene sorbitan monostearate ("Nion ST221" by Nichiyu Corporation) as a surfactant, 2- (8-heptadecenyl) -2-imidazoline as a dispersing agent It was added so as to be 0.3 wt% of -1-ethanol. As the phosphor, (Y, Gd) BO ₃ : Eu (red phosphor) was added so as to have a composition ratio shown in Table 5, sufficiently kneaded using a high speed stirring device, and kneaded with three roll mills until a smooth state was obtained. A phosphor paste composition was prepared.

(Examples 20 and 21 and 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 the components were adjusted to the composition ratios shown in Table 5 or Table 6.

(evaluation)

The fluorescent substance paste compositions manufactured 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 was placed in a 250 ml polyethylene container, and the viscosity of the phosphor paste composition under conditions of a temperature of 23 ° C. and a rotation speed of 10 rpm using a type B viscometer (“DⅦ + Pro” manufactured by BROOK FILED). ^A _{10 rpm} (Pa · s) was measured. Subsequently, 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 stored using a type B viscometer under the conditions of a temperature of 23 ° C. and a rotation speed of 10 rpm. the viscosity of the paste composition measuring η ^B _10rpm (Pa · s), followed by calculating the viscosity change rate (%).

The viscosity change rate (%) was computed by the following formula | equation.

Viscosity change rate (%) = [(η ^A _{10 rpm} -η ^B _{10 rpm} ) / η ^A _{10 rpm} ] × 100

(2) storage stability (with or without precipitates)

The phosphor paste composition immediately after dispersing the phosphor was placed in a 250 ml polyethylene container and visually observed whether a precipitate was present at the bottom of the container. Then, after storing the fluorescent paste composition put into the polyethylene container for 1 month in the environment of the temperature of 23 degreeC, and 50% of humidity, it was visually observed whether a deposit exists in the bottom of a container again.

According to the following criteria, it was evaluated whether a precipitate was present at the bottom of the container.

(Circle): A deposit was not observed in the bottom of a container.

X: The deposit was observed in the bottom of a container.

(3) screen printability

The phosphor paste composition immediately after dispersing the phosphor was placed 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%. Subsequently, screen printing was performed using the fluorescent substance paste composition stored in the environment of the temperature of 23 degreeC, and 50% of humidity. Screen printing includes screen printing machines ("MT-320 TV" manufactured by Microtec), screen making ("SX230 ° B" manufactured by Tokyo Process Service, Inc. (oil 20 µm, screen frame 320 mm x 320 mm)), printed board (soda) -Screen 150 mm x 150 mm, thickness 15 mm) was screen-printed on condition of the following screen printing machines.

Gap: 2.0 mm

Squeegee speed: 50mm / s

Scraper speed: 50mm / s

Squeegee pressure: 0.25 MPa

Scraper pressure: 0.17 MPa

Back pressure: 0.10 MPa

The aspect of screen printing is shown in FIG. The printing pattern 1 shown in FIG. 1 is a printing pattern formed in a horizontal direction with respect to the moving direction of a squeegee. The printing pattern 2 shown in FIG. 1 is a printing pattern formed in the inclination 45 degree direction with respect to the moving direction of a squeegee. About the printing pattern 1 and the printing pattern 2 shown in FIG. 1, screen printability was evaluated according to the following criteria.

(Circle): A crack was not seen in the print pattern.

X: Cracks were seen in the print pattern or could not be printed.

(Example 22)

100 parts by weight of methyl methacrylate (manufactured by Mitsubishi Rayon Co., Ltd.) and mercaptosuccinic acid (manufactured by Wako Pure Chemical Industries, Ltd.) as a chain transfer agent were added to a 2 L separable flask equipped with a stirrer, a cooler, a thermometer, and a nitrogen gas inlet. A weight part and 100 weight part of texanol (made by Kyowa Hakko Chemical Co., Ltd.) were mixed as an organic solvent, and the monomer liquid mixture was obtained.

After removing the dissolved oxygen by bubbling the obtained monomer liquid mixture for 20 minutes using nitrogen gas, the temperature of the separable flask system was replaced with nitrogen gas and stirred until the solution temperature reached 95 ° C. After the temperature was reached, a solution in which the polymerization initiator was diluted with ethyl acetate was added. In addition, an ethyl acetate solution containing a polymerization initiator was added several times during the polymerization.

After 10 hours from the start of the polymerization, the mixture was cooled to room temperature and the polymerization was terminated. This obtained the texanol solution of polymethyl methacrylate (PMMA) as (meth) acrylic resin.

As a result of analyzing by GPC about the obtained (meth) acrylic resin, the weight average molecular weight by polystyrene conversion was 5000. In addition, the column LF-804 by the SHOKO company was used for the measurement of the polystyrene conversion weight average molecular weight.

Texanol was further added to the obtained polymethylmethacrylate solution, and it disperse | distributed using the high speed disperser, and the binder resin composition which contains 39.7 weight% of tertecsanol was contained with respect to 25 weight% of polymethylmethacrylates.

0.2 weight% of polyoxyethylene (POE) (20) sorbitan monolaurate ("Leodore TW-L120" by Kao Corporation) as a surfactant with respect to the obtained binder resin composition, and polycarboxylic acid (Kusumoto as a dispersing agent) 0.1 wt% of Hyosung Co., Ltd., "Disparon 2150") and 35 wt% of green phosphor powder (manufactured by Nichia Chemical, Zn ₂ SiO ₄ : Mn) are added, and the phosphor paste composition is sufficiently kneaded using three rolls. 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 the components were adjusted to the composition ratios shown in Table 8.

(Comparative Examples 18, 19)

A binder resin composition and a phosphor paste composition were produced in the same manner as in Example 22 except that the components were adjusted to the composition ratios shown in Table 8.

<Evaluation>

The following evaluation was performed about the fluorescent substance paste compositions obtained in Examples 22-25 and Comparative Examples 18 and 19. The results are shown in Table 9.

(1) viscosity evaluation

The viscosity (eta) _{10 rpm} (Pa * s) of the fluorescent substance paste composition was measured on the conditions of the temperature 23 degreeC and rotation amount 10rpm using the Brookfield viscometer ("D '+ Pro" by BROOK FIELD) of the obtained fluorescent paste composition.

(2) surface roughness evaluation

The obtained phosphor paste composition was applied to a slide glass (2 cm × 5 cm) so as to have a thickness of 12.5 μm. After drying the slide glass which apply | coated the phosphor paste composition for 10 minutes at 120 degreeC, the surface of the phosphor paste composition apply | coated with the surface roughness meter ("Surfcoder SE-30D" by Kosaka Research Institute) was measured. The surface roughness Ra was evaluated based on the following criteria.

○: less than Ra = 1.0 μm

X: Ra = 1.0 micrometer or more

(3) dispersibility evaluation

The distribution density of the fluorescent substance was measured for the obtained fluorescent substance paste composition by the grind gauge (the Ericsson company make, 0-15 micrometers), and the scale of the point where the aggregated fluorescent substance appeared was observed. However, the measurement was performed 5 times and the average value of the scale of the point where the fluorescent substance aggregated in 10 lines appeared was evaluated. Dispersibility was evaluated according to the following criteria.

○: less than 10 μm

X: 10 micrometers or more

(4) screen printing

The obtained fluorescent substance paste composition was screen-printed in the environment of the temperature of 23 degreeC, and 50% of humidity.

Screen printing includes screen printing machines ("MT-320 TV" manufactured by Microtec), screen making ("SX230 ° B" manufactured by Tokyo Process Service, Inc. (oil 20 µm, screen range 320 mm x 320 mm)), printed board (soda) -Screen 150 mm x 150 mm, thickness 15 mm) was screen-printed on condition of the following screen printing machines.

Gap: 2.0 mm

Squeegee speed: 50mm / 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 stereo microscope.

(Double-circle): There is no dispersion in the thickness of a printed image, a printed image is thick enough, and its density is high.

○: There is no variation in the thickness of the printed image.

(Triangle | delta): Although there is no variation in the thickness of a printed image, a printed image is very thin.

X: There is a deviation in the thickness of the printed image.

According to the present invention, it is possible to provide a phosphor paste composition which can be printed by screen printing, having good dispersibility of the phosphor, excellent storage stability, and degreasing at low temperature.

Claims (14)

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,
The viscosity of 8-40 Pa.s when measured by setting probe rotation speed to 10 rpm using the Brookfield viscometer at 23 degreeC, The phosphor paste composition characterized by the above-mentioned. The method of claim 1,
The polyoxyethylene sorbitan fatty acid ester is a compound represented by the following general formula (1) and / or a compound represented by the following general formula (2) or a compound represented by the following general formula (3).
[Formula 1]

(2)

(3)

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

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 is H, C _n H _{2n + 1} (n is 1 to 5 Integer) 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), or C _n H _2n OH (n is 1 to 5), and R ⁷ represents H or C _n H _{2n + 1} (n is an integer of 1 to 5).
[Chemical Formula 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 is H, C _n H _{2n + 1} (n is 1 to 5) Integer) 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 C _n H _2n OH (n is represents an integer of 1-5), R ¹¹ is H, or C _n H _{2n +1 (n} represents an integer of 1 to 5).

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