WO2011016442A1

WO2011016442A1 - Inorganic microparticle dispersion paste

Info

Publication number: WO2011016442A1
Application number: PCT/JP2010/063075
Authority: WO
Inventors: 山内健司; 宮崎寛子; 麻生隆浩; 杉田大平; 高橋英之
Original assignee: 積水化学工業株式会社
Priority date: 2009-08-04
Filing date: 2010-08-03
Publication date: 2011-02-10
Also published as: KR101632096B1; JP2011213980A; TW201107389A; TWI483977B; CN102471541B; KR20120052374A; CN102471541A; JP5600488B2

Abstract

Provided is an inorganic microparticle dispersion paste that can form a sintered layer having excellent surface smoothness. Said inorganic microparticle dispersion paste contains: at least one species chosen from a group comprising ethyl cellulose, (meth)acryl resins, and polyvinyl acetal resins; an organic compound; inorganic microparticles; and an organic solvent. The organic compound has one or more hydroxyl groups, is solid at room temperature, and has a boiling point of less than 300°C.

Description

Inorganic fine particle dispersion paste

The present invention relates to an inorganic fine particle dispersed paste capable of forming a sintered layer excellent in surface smoothness.

In recent years, an inorganic fine particle dispersed paste in which inorganic fine particles such as conductive powder and ceramic powder are dispersed in a binder resin has been used to obtain sintered bodies having various shapes. In particular, phosphor pastes in which phosphors are dispersed as inorganic fine particles in a binder resin and glass pastes in which low-melting-point glass is dispersed are used in plasma display panels and the like, and demand is increasing in recent years.
A ceramic paste in which barium titanate or alumina as inorganic fine particles is dispersed in a binder resin is formed into a green sheet and used for a multilayer electronic component such as a multilayer ceramic capacitor.
Furthermore, the back electrode of the solar cell panel is usually formed by applying a paste in which aluminum powder is dispersed by screen printing or the like, drying, and firing.

For example, the dielectric layer of a plasma display panel can be obtained by printing a glass paste on a glass substrate, drying the solvent in a blowing oven circulated through the furnace, and then degreasing and firing in a high-temperature oven. It is formed. As a glass paste for forming a dielectric layer, for example, Patent Document 1 discloses a composition for a dielectric layer of a plasma display panel, a glass frit containing at least a glass component, a dispersant, and a pyrolysis binder. And a solvent, and the dispersant is a polycarboxylic acid polymer compound, and the dielectric layer composition is applied onto a support and then dried. The resulting green sheet is disclosed.

Patent Document 1 describes that the dispersion state of the glass frit is effectively improved in the dielectric layer composition described in the same document.
Such improvement of the dispersibility of the inorganic fine particles is important in order to form a uniform sintered layer and not cause variations in the characteristics of the sintered layer. However, since the sintered layer is formed only after the printing, drying, degreasing, and firing steps of the inorganic fine particle dispersed paste, simply improving the uniformity in the paste state, that is, the dispersibility of the inorganic fine particles, is the final. It is difficult to ensure sufficient uniformity of the sintered layer formed on the substrate.

In addition, like the green sheet described in Patent Document 1, it has been studied to form a uniform sintered layer by processing the inorganic fine particle dispersed paste in advance into a sheet shape and using the obtained green sheet. When using a green sheet, the problem is that the adhesion of the green sheet to the substrate is insufficient.

JP 2004-002164 A

An object of this invention is to provide the inorganic fine particle dispersion | distribution paste which can form the sintered layer excellent in surface smoothness.

The present invention is an inorganic fine particle dispersed paste containing at least one selected from the group consisting of ethyl cellulose, (meth) acrylic resin and polyvinyl acetal resin, an organic compound, inorganic fine particles, and an organic solvent, The organic compound is an inorganic fine particle-dispersed paste having one or more hydroxyl groups and having a normal temperature solid and a boiling point of less than 300 ° C.
The present invention is described in detail below.

Usually, a high boiling point solvent is used in the inorganic fine particle dispersed paste for forming a sintered layer in order to ensure printability. Furthermore, in order to dry a high boiling point solvent efficiently and to improve productivity, the ventilation oven is used in the drying process after printing. The inventors of the present invention caused surface roughness in the coating layer of the inorganic fine particle dispersed paste due to air blowing in the oven, resulting in reduced surface smoothness of the sintered layer and deteriorated performance of the sintered layer. I found out.

The present inventors have at least one hydroxyl group in addition to at least one selected from the group consisting of ethyl cellulose, (meth) acrylic resin and polyvinyl acetal resin, inorganic fine particles and organic solvent, and The inorganic fine particle dispersion paste containing an organic compound having a boiling point of less than 300 ° C. is well-dried in the drying process after printing, and the surface is roughened by receiving air in the oven when drying in the oven. It was found that the film can be uniformly dried without causing a skinning phenomenon caused by the entanglement of the resin. Furthermore, the present inventors have found that a sintered layer formed using the inorganic fine particle dispersed paste is excellent in surface smoothness, and have completed the present invention.

The inorganic fine particle-dispersed paste of the present invention contains at least one selected from the group consisting of ethyl cellulose, (meth) acrylic resin, and polyvinyl acetal resin.
The ethyl cellulose is not particularly limited, and a grade may be appropriately selected according to the printing method of the obtained inorganic fine particle dispersed paste, the desired thickness of the sintered layer, and the like. In particular, when screen printing is performed, ethyl cellulose having thixotropy is generally preferable, and grades of ethyl cellulose such as STD45 and STD100 are preferable. In addition, when obtaining a thick sintered layer, it is necessary to increase the composition ratio of the inorganic fine particles in the inorganic fine particle dispersed paste, and the viscosity of the inorganic fine particle dispersed paste tends to increase. Therefore, low viscosity specifications such as STD4, STD10, etc. Grade of ethylcellulose is preferred.

The (meth) acrylic resin is not particularly limited as long as it decomposes at a low temperature of about 350 to 400 ° C., but 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 (meth) acrylate, benzyl (meth) acrylate And a polymer comprising at least one selected from the group consisting of (meth) acrylic monomers having a polyoxyalkylene structure is preferred. Here, for example, (meth) acrylate means acrylate or methacrylate.
Among them, polymethyl methacrylate (polymer of methacrylate, Tg 105 ° C.) having a high glass transition temperature (Tg) is preferable because a high viscosity can be obtained with a small amount of resin. Polymethacrylate is also excellent in low temperature degreasing properties. Furthermore, since the inorganic fine particle-dispersed paste of the present invention contains an organic compound described later, a polymer having a component derived from butyl methacrylate or isobutyl methacrylate is preferable.

Moreover, the said (meth) acrylic resin may have the segment which consists of a monomer which has a polar group.
Examples of the monomer having a polar group include 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, methacrylic acid, glycidyl methacrylate, glycerol monomethacrylate, and the like.

When it has the segment derived from the monomer which has the said polar group, it is preferable that content of the segment derived from the monomer which has the said polar group is 20 weight% or less.
If the content of the segment derived from the monomer having the polar group exceeds 20% by weight, thermal decomposition at low temperature is impaired, or soot is attached to the inorganic fine particles, resulting in a large amount of residual carbon in the sintered body. Sometimes it becomes. More preferably, it is 10 parts by weight or less.

The (meth) acrylic resin preferably has a hydrophilic functional group at the molecular end. The hydrophilic functional group is not particularly limited, but is preferably a carbonyl group, an amino group, or an amide group.
In general, when a (meth) acrylic resin in which a highly interactive functional group such as a carbonyl group, amino group, or amide group is introduced into the ester substituent of a (meth) acrylic monomer, In the firing step, the depolymerization of the (meth) acrylic resin is inhibited, the thermal decomposition end temperature is increased, and the thermal decomposability is extremely deteriorated.
On the other hand, when a (meth) acrylic resin having a carbonyl group, an amino group, an amide group or the like at the molecular end is used, the depolymerization of the (meth) acrylic resin is not inhibited, and the thermal decomposition end temperature is Almost no effect. In addition, since inorganic fine particles such as glass powder have high interaction properties with carbonyl groups, amino groups, amide groups, etc., (meth) acrylic resins having carbonyl groups, amino groups, amide groups, etc. at the molecular ends were used. In this case, one molecular end of the (meth) acrylic resin is adsorbed on the surface of the inorganic fine particles, and the other is extended to the organic solvent side, preventing re-aggregation of the inorganic fine particles and improving dispersion stability. it can.

Although the weight average molecular weight by polystyrene conversion of the said (meth) acrylic resin is not specifically limited, A preferable minimum is 5000 and a preferable upper limit is 500,000. When the weight average molecular weight is less than 5,000, the resulting inorganic fine particle dispersed paste may not have sufficient viscosity and screen printing properties may be deteriorated. In addition, air is blown in an oven in a drying process after printing. When the surface roughness due to receiving increases, the surface smoothness of the sintered layer may decrease. When the weight average molecular weight is more than 500,000, the adhesive strength of the obtained inorganic fine particle dispersed paste becomes too high, so that the yarn may be generated and the screen printability may be deteriorated. The upper limit with the said preferable weight average molecular weight is 100,000, and a more preferable upper limit is 50000. In particular, the polystyrene equivalent weight average molecular weight of the (meth) acrylic resin is preferably 10,000 to 50,000 because a clear image can be obtained during screen printing.
The weight average molecular weight in terms of polystyrene can be obtained by GPC measurement using, for example, a column LF-804 (manufactured by Showa Denko KK) as a column.

The method for producing the (meth) acrylic resin is not particularly limited. For example, the above-mentioned (meth) acrylic monomer is subjected to a free radical polymerization method under a polymerization initiator having a carbonyl group, an amino group, an amide group, or the like. , Copolymerization by a conventionally known method such as a living radical polymerization method, an iniferter polymerization method, an anionic polymerization method, a living anion polymerization method, or a chain transfer agent having a carbonyl group, an amino group, an amide group, etc. Examples thereof include a method of copolymerizing the above-described (meth) acrylic monomer by a conventionally known method such as a free radical polymerization method, a living radical polymerization method, an iniferter polymerization method, an anion polymerization method, or a living anion polymerization method. These methods may be used independently and may use 2 or more types together.
In the method for producing the (meth) acrylic resin, by using a polymerization initiator having a carbonyl group, an amino group, an amide group or the like as a radical polymerization initiator, a carbonyl group, an amino group, an amide at more molecular ends. Groups and the like can be introduced. The introduction of a carbonyl group, amino group, amide group or the like only at the molecular end of the (meth) acrylic resin can be confirmed by, for example, ¹³ C-NMR.

The polyvinyl acetal resin is not particularly limited as long as it has excellent compatibility with the organic solvent described later, but is obtained by acetalizing a polyvinyl alcohol resin having a saponification degree of 80 mol% or more, It is preferable that the degree of polymerization is 1000 to 4000 and the degree of acetalization is 60 to 80 mol%.

The saponification degree of the polyvinyl alcohol is preferably 80 mol% or more. If the degree of saponification is less than 80 mol%, the acetalization reaction becomes difficult due to poor solubility of polyvinyl alcohol in water, and if the amount of hydroxyl groups is small, the acetalization reaction itself may be difficult. is there.

The degree of polymerization of the polyvinyl alcohol is preferably 1000 to 4000.
When the polymerization degree is less than 1000, for example, when used as a material for a ceramic green sheet, the strength may be insufficient. If the degree of polymerization exceeds 4000, the solubility in water may decrease, or the viscosity of the aqueous solution may become too high, making acetalization difficult. In addition, the solution viscosity becomes too high and the coatability is lowered.
In addition, the polymerization degree of the said polyvinyl acetal uses the polymerization degree of polyvinyl alcohol which is a raw material at the time of synthesize | combining. Moreover, when mixing 2 or more types of polyvinyl alcohol, the average of these polymerization degrees is used.

The polyvinyl alcohol can be obtained by saponifying a vinyl ester polymer.
Examples of the vinyl ester include vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate and the like, and vinyl acetate is preferable from the economical viewpoint.
The polyvinyl alcohol preferably contains an α-olefin in the main chain.
Since the hydrogen bond strength of the polyvinyl acetal resin is weakened by the α-olefin, the viscosity stability over time can be improved, and the screen printability can be improved.

Examples of the α-olefin include methylene, ethylene, propylene, isopropylene, butylene, isobutylene, pentylene, hexylene, cyclohexylene, cyclohexylethylene, cyclohexylpropylene, and the like, and ethylene is particularly preferable.
The content of the α-olefin is preferably 1 to 20 mol%.
When the content of the α-olefin is less than 1 mol%, the properties of the obtained polyvinyl acetal resin are no different from those of an unmodified polyvinyl acetal resin, and when it exceeds 20 mol%, the solubility of polyvinyl alcohol in water As a result, the acetalization reaction may become difficult, and the resulting polyvinyl acetal resin may become too hydrophobic to reduce its solubility in organic solvents.

The polyvinyl alcohol may be copolymerized with other ethylenically unsaturated monomers as long as the effects of the present invention are not impaired.
Examples of such ethylenically unsaturated monomers include acrylic acid, methacrylic acid, (anhydrous) phthalic acid, (anhydrous) maleic acid, (anhydrous) itaconic acid, acrylonitrile methacrylonitrile, acrylamide, methacrylamide, and trimethyl. -(3-acrylamido-3-dimethylpropyl) -ammonium chloride, acrylamido-2-methylpropanesulfonic acid and its sodium salt, ethyl vinyl ether, butyl vinyl ether, N-vinyl pyrrolidone, vinyl chloride, vinyl bromide, vinyl fluoride , Vinylidene chloride, vinylidene fluoride, tetrafluoroethylene, sodium vinyl sulfonate, sodium allyl sulfonate and the like.
Also use terminal-modified polyvinyl alcohol obtained by copolymerizing vinyl ester monomer such as vinyl acetate with ethylene in the presence of thiol compounds such as thiol acetic acid and mercaptopropionic acid, and saponifying it. Can do.

The aldehyde used in the above reaction is not particularly limited. For example, formaldehyde (including paraformaldehyde), acetaldehyde (including paraacetaldehyde), propionaldehyde, butyraldehyde, amylaldehyde, hexylaldehyde, heptylaldehyde, 2-ethylhexylaldehyde, Examples include cyclohexyl aldehyde, furfural, glyoxal, glutaraldehyde, benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxyaldehyde, m-hydroxyaldehyde, phenylacetaldehyde, phenylpropionaldehyde and the like.
These aldehydes may be used alone or in combination of two or more, and acetaldehyde and / or butyraldehyde is preferably used.

The polyvinyl acetal resin is prepared by dissolving a polyvinyl alcohol resin in warm water, adding an aldehyde so as to have a predetermined degree of acetalization in the presence of an acid catalyst, reacting, and then washing, neutralizing, and drying. Obtainable.
The acid catalyst is not particularly limited, and any organic acid or inorganic acid can be used. Examples thereof include acetic acid, paratoluenesulfonic acid, nitric acid, sulfuric acid, and hydrochloric acid.
Moreover, as an alkali used for neutralization, sodium hydroxide, potassium hydroxide, ammonia, sodium acetate, sodium carbonate, sodium hydrogencarbonate, potassium carbonate etc. are mentioned, for example.

The degree of acetalization of the polyvinyl acetal resin used in the present invention is preferably 60 to 80 mol%. When the degree of acetalization is less than 60 mol%, the hydrogen bondability of the polyvinyl acetal resin becomes too strong, and sufficient screen printability may not be obtained.
On the other hand, the polyvinyl acetal resin having a degree of acetalization exceeding 80 mol% is generally difficult to produce industrially. (The maximum acetalization degree is preferably 81.6 mol% according to the theoretical calculation by PJ Flory. J. Am. Chem. Soc., 61, 1518 (1939)).

The content of at least one selected from the group consisting of ethyl cellulose, (meth) acrylic resin and polyvinyl acetal resin in the inorganic fine particle-dispersed paste of the present invention is not particularly limited, but the preferred lower limit is 5% by weight and the preferred upper limit is 25. % By weight. When the content of at least one selected from the group consisting of ethyl cellulose, (meth) acrylic resin and polyvinyl acetal resin is less than 5% by weight, the resulting inorganic fine particle dispersed paste cannot obtain a sufficient viscosity, The screen printability may be deteriorated, and the surface smoothness of the sintered layer may be reduced due to increase in surface roughness due to receiving air blow in the oven in the drying step after printing. When the content exceeds 25% by weight, the resulting inorganic fine particle-dispersed paste may have excessively high viscosity and adhesive strength, resulting in poor screen printability.

The inorganic fine particle-dispersed paste of the present invention contains an organic compound having one or more hydroxyl groups and having a normal temperature solid and a boiling point of less than 300 ° C.
The organic compound is solid at room temperature. When the organic compound is solid at room temperature, the resulting inorganic fine particle-dispersed paste is suppressed in surface roughness due to being blown in an oven in the drying step after printing, and the sintered layer is excellent in surface smoothness.
In addition, although the said organic compound is solid at normal temperature, a paste-form inorganic fine particle dispersion | distribution paste can be obtained by melt | dissolving in the organic solvent mentioned later.
The organic compound is different from the organic solvent described later.

The mechanism of improving the drying property by adding an organic compound having at least one hydroxyl group and having a normal temperature solid and a boiling point of less than 300 ° C. is considered as follows.
The surface of the inorganic fine particles added to the inorganic fine particle-dispersed paste is in a very high polarity state, and has a function of sucking high polar functional groups. Usually, when an organic material having a highly polar functional group is not added to the inorganic fine particle-dispersed paste, the fine particles are aggregated in a solvent to cause precipitation.
Therefore, by adding an organic compound having one or more hydroxyl groups and having a normal temperature solid and a boiling point of less than 300 ° C., in the inorganic fine particle dispersed paste, it becomes liquid by mixing with an organic solvent. A layer capable of adsorbing preferentially on the surface of the inorganic fine particles and evaporating around the inorganic fine particles under dry conditions can be formed.

On the other hand, since at least one binder resin selected from the group consisting of ethyl cellulose, (meth) acrylic resin and polyvinyl acetal resin is a high molecular weight polymer, the organic solvent is removed from the surface of the inorganic fine particle dispersed paste under dry conditions. By drying, the surface is skinned and a thin resin layer is formed.
The surface resin layer formed with such drying is very non-uniform, depends on the drying conditions, and forms a more non-uniform layer under strong drying conditions under blowing conditions. For this reason, the organic solvent present under the skinned resin layer is difficult to evaporate, and unevenness is likely to occur on the surface of the coating film.
On the other hand, the organic compound having a layer formed on the surface of the inorganic fine particles evaporates under dry conditions, thereby forming a window for evaporating the internal organic solvent. Therefore, it is possible to reduce the drying unevenness of the organic solvent due to resin skinning, and even when drying is inadequate, it is a solid at room temperature, so it hardly acts as a plasticizer and maintains smoothness. It becomes easy.

The organic compound has a boiling point of less than 300 ° C. When the boiling point of the organic compound is 300 ° C. or higher, the resulting inorganic fine particle-dispersed paste has reduced drying properties in the drying step after printing, and the surface smoothness of the sintered layer is reduced. The organic compound preferably has a boiling point of less than 280 ° C, more preferably less than 260 ° C.
The lower limit of the boiling point of the organic compound is not particularly limited, but the boiling point is preferably 160 ° C. or higher. When the organic compound has a boiling point of less than 160 ° C., the obtained inorganic fine particle dispersed paste is easily dried during printing, and may cause problems when used for continuous printing for a long time. In addition, the said boiling point means the boiling point in a normal pressure.

The organic compound has one or more hydroxyl groups. By having one or more of the above hydroxyl groups, the storage stability of the resulting inorganic fine particle dispersed paste can be increased, and the viscosity of the inorganic fine particle dispersed paste can be increased by the interaction between the hydroxyl group, the resin and the organic solvent. The viscosity can be made suitable for screen printing or the like.

The organic compound is not particularly limited as long as it has one or more hydroxyl groups and is a solid at normal temperature and has a boiling point of less than 300 ° C., but an alcohol-based organic compound composed of an aliphatic chain having 5 to 20 carbon atoms is preferable.
The alcohol organic compound is not particularly limited. For example, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, myristyl alcohol, cetyl alcohol, 2,2-dimethyl-1,3- Examples include propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, trimethylolpropane, and pentaerythritol.
Among them, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propane, which have a high ratio of hydroxyl group to carbon number Since the diol has a boiling point of about 200 ° C. and a softening point of 120 ° C. or more, it can be suitably used as an inorganic fine particle dispersed paste used for screen printing.

The content of the organic compound in the inorganic fine particle-dispersed paste of the present invention is not particularly limited, but the preferred lower limit is 1% by weight and the preferred upper limit is 30% by weight. When the content of the organic compound is less than 1% by weight, the resulting inorganic fine particle-dispersed paste has reduced drying properties in the drying step after printing, or increased surface roughness due to receiving air blowing in the oven, The surface smoothness of the sintered layer may be reduced by causing a skinning phenomenon caused by the entanglement of the resin. When the content of the organic compound exceeds 30% by weight, the obtained inorganic fine particle-dispersed paste may have poor storage stability.

The inorganic fine particle dispersed paste of the present invention contains an organic solvent.
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, Butyl carbitol, butyl carbitol acetate, texanol, isophorone, butyl lactate, dioctyl phthalate, dioctyl adipate, benzyl alcohol, phenylpropylene glycol, cresol, terpineol, terpine acetate, dihydroterpineol, dihydroterpineol acetate, acetone, methyl ethyl ketone, methanol, Ethanor , N- propanol, isopropanol, n- butanol, toluene, and xylene. These organic solvents may be used alone or in combination of two or more.

The content of the organic solvent in the inorganic fine particle-dispersed paste of the present invention is not particularly limited, but a preferred lower limit is 10% by weight and a preferred upper limit is 60% by weight. When the content of the organic solvent is less than 10% by weight, the viscosity and adhesive strength of the resulting inorganic fine particle-dispersed paste may become too high, resulting in poor screen printability. When the content of the organic solvent exceeds 60% by weight, the resulting inorganic fine particle-dispersed paste may not have a sufficient viscosity and may have poor screen printability. The surface smoothness of the sintered layer may decrease due to a decrease in surface roughness or an increase in surface roughness due to receiving air blow in the oven.
In addition, when baking the inorganic fine particle dispersion paste of this invention, it is preferable to bake in the state which dried the said organic solvent and organic compound. If the organic solvent or organic compound is insufficiently dried, and baking is performed in a state where the organic solvent or organic compound remains in the interior, soot generated by thermal decomposition of the binder resin is likely to be adsorbed on the surface of the fine particles. Compared with the case of complete drying, the carbon residue may be increased.

The inorganic fine particle dispersed paste of the present invention contains inorganic fine particles.
The inorganic fine particles are not particularly limited, and examples thereof include glass powder, ceramic powder, phosphor fine particles, silicon oxide, metal fine particles, metal oxide fine particles, and the like.

The glass powder is not particularly limited, and examples thereof include glass powders such as bismuth oxide glass, silicate glass, lead glass, zinc glass, and boron glass, CaO—Al ₂ O ₃ —SiO ₂ series, MgO—Al ₂ O, and the like. ₃ -SiO ₂ based _glass powder or the like of the LiO ₂ -Al ₂ O 3 -SiO ₂ system such as various silicon oxide and the like.
Further, as the above glass powder, PbO—B ₂ O ₃ —SiO ₂ mixture, BaO—ZnO—B ₂ O ₃ —SiO ₂ mixture, ZnO—Bi ₂ O ₃ —B ₂ O ₃ —SiO ₂ mixture, Bi ₂ O ₃ —B ₂ O ₃ —BaO—CuO mixture, Bi ₂ O ₃ —ZnO—B ₂ O ₃ —Al ₂ O ₃ —SrO mixture, ZnO—Bi ₂ O ₃ —B ₂ O ₃ mixture, Bi ₂ O ₃ — SiO ₂ mixture, P ₂ O ₅ —Na ₂ O—CaO—BaO—Al ₂ O ₃ —B ₂ O ₃ mixture, P ₂ O ₅ —SnO mixture, P ₂ O ₅ —SnO—B ₂ O ₃ mixture, P ₂ O ₅ —SnO—SiO ₂ mixture, CuO—P ₂ O ₅ —RO mixture, SiO ₂ —B ₂ O ₃ —ZnO—Na ₂ O—Li ₂ O—NaF—V ₂ O ₅ mixture, P ₂ O ₅ —ZnO—SnO— ₂ O-RO _mixture, B ₂ O ₃ -SiO ₂ -ZnO _{_{_{_{mixture, B 2 O 3 -SiO 2 -Al}}}} 2 O 3 -ZrO 2 _{_{_{mixture, SiO 2 -B 2 O 3 -ZnO}}} -R 2 O-RO mixture SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —RO—R ₂ O mixture, SrO—ZnO—P ₂ O ₅ mixture, SrO—ZnO—P ₂ O ₅ mixture, BaO—ZnO—B ₂ O ₃ — Glass powders such as SiO ₂ mixtures can also be used. R is an element selected from the group consisting of Zn, Ba, Ca, Mg, Sr, Sn, Ni, Fe, and Mn.
In particular, glass powder of a PbO—B ₂ O ₃ —SiO ₂ mixture, a BaO—ZnO—B ₂ O ₃ —SiO ₂ mixture or a ZnO—Bi ₂ O ₃ —B ₂ O ₃ —SiO ₂ mixture containing no lead, etc. Lead-free glass powder is preferred.

The ceramic powder is not particularly limited, and examples thereof include alumina, zirconia, titanium oxide, barium titanate, alumina nitride, silicon nitride, and boron nitride.
Moreover, nano-ITO used for a transparent electrode material, nano-titanium oxide used for a dye-sensitized solar cell, etc. can be used suitably.
The phosphor fine particles are not particularly limited, and examples thereof include BaMgAl ₁₀ O ₁₇ : Eu, Zn ₂ SiO ₄ : Mn, (Y, Gd) BO ₃ : Eu, and the like.

The metal fine particles are not particularly limited, and examples thereof include powders made of nickel, palladium, platinum, gold, silver, aluminum, tungsten, alloys thereof, and the like.
Further, metals such as copper and iron, which have good adsorption characteristics with a carboxyl group, amino group, amide group and the like and are easily oxidized, can be suitably used. These metal powders may be used alone or in combination of two or more.

Although content of the said inorganic fine particle in the inorganic fine particle dispersion paste of this invention is not specifically limited, A preferable minimum is 20 weight% and a preferable upper limit is 90 weight%. When the content of the inorganic fine particles is less than 20% by weight, the obtained inorganic fine particle-dispersed paste cannot obtain a sufficient viscosity and screen printing properties may be deteriorated. The surface smoothness of the sintered layer may be reduced by increasing the surface roughness due to receiving air in the interior. If the content of the inorganic fine particles exceeds 90% by weight, the resulting inorganic fine particle-dispersed paste may have too high a viscosity and screen printing properties may deteriorate.

The inorganic fine particle-dispersed paste of the present invention preferably contains a surfactant in order to stabilize the compatibility between the organic compound and other materials. The surfactant is not particularly limited, but a nonionic surfactant is preferable.
Although content of the said nonionic surfactant in the inorganic fine particle dispersion paste of this invention is not specifically limited, A preferable upper limit is 5 weight%. Although the nonionic surfactant has good thermal decomposability, if the content exceeds 5% by weight, the thermal decomposability of the inorganic fine particle dispersed paste may be lowered.

The method for producing the inorganic fine particle-dispersed paste of the present invention is not particularly limited, and examples thereof include conventionally known stirring methods. Specifically, for example, selected from the group consisting of ethyl cellulose, (meth) acrylic resin, and polyvinyl acetal resin. And a method in which at least one of the above-mentioned organic compound, the above-mentioned organic solvent, the above-mentioned inorganic fine particles, and other components added as necessary are stirred with a three-roll or the like.

The inorganic fine particle-dispersed paste of the present invention is well dried in the drying step after printing, the surface roughness due to receiving air blow in the oven is suppressed, and the adverse effect of the skinning phenomenon during drying can be prevented. A sintered layer having excellent surface smoothness can be formed. Therefore, for example, suitable as glass paste when glass powder is used as inorganic fine particles, ceramic paste when ceramic powder is used as inorganic fine particles, and conductive paste when metal such as aluminum or conductive powder is used as inorganic fine particles Used for.
Among these, glass paste when glass powder is used as the inorganic fine particles is preferably used for forming a dielectric layer of a plasma display panel. A glass dielectric produced using such a glass paste is also one aspect of the present invention.

Furthermore, the inorganic fine particle-dispersed paste of the present invention is characterized in that it can be dried quickly while preventing the skinning phenomenon during drying. Therefore, when a conventional resin paste is used, it can be suitably used for a member that is difficult to maintain its shape by flowing during drying. The state where the shape cannot be maintained is also referred to as “sag”.
For example, when a conventional resin paste is used for the phosphor in the cell on the back plate of the plasma display, the surface electrode of the solar battery cell, etc., it drew during drying and the height could not be maintained after printing. By using the inorganic fine particle-dispersed paste of the present invention, it becomes possible to remove the organic solvent before dripping and flowing low during drying, and it can be suitably used as a material for a flat panel display.
A flat panel display produced using the inorganic fine particle dispersed paste of the present invention is also one aspect of the present invention.

ADVANTAGE OF THE INVENTION According to this invention, the inorganic fine particle dispersion | distribution paste which can form the sintered layer excellent in surface smoothness can be provided.

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

(Polymerization example 1)
100 parts by weight of isobutyl methacrylate (IBMA) and 100 parts by weight of texanol as an organic solvent were mixed in a 2 L separatory flask equipped with a stirrer, a cooler, a thermometer, an oil bath, and a nitrogen gas inlet 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 up until the oil bath reached 130 ° C. while stirring. . As a polymerization initiator, a solution in which 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide] was dispersed with texanol was added. Further, a texanol solution containing a polymerization initiator was added several times during the polymerization, and 1.5 parts by weight of the polymerization initiator was added to 100 parts by weight of the monomer in total.

Seven hours after the start of polymerization, the reaction solution was cooled to room temperature to complete the polymerization. Thereby, a texanol solution of (meth) acrylic resin (Poly (IBMA)) having an amide group at the molecular end was obtained.
The obtained polymer was analyzed by gel permeation chromatography using column LF-804 (manufactured by Showa Denko KK) as the column, and the weight average molecular weight in terms of polystyrene was 40,000.

(Polymerization example 2)
In a 2 L separate flask equipped with a stirrer, cooler, thermometer, oil bath, and nitrogen gas inlet, 100 parts by weight of a 1: 1 mixture of butyl methacrylate and methyl methacrylate (BMA / MMA), texanol as an organic solvent 100 parts by weight were mixed to obtain a monomer mixture.

Seven hours after the start of polymerization, the reaction solution was cooled to room temperature to complete the polymerization. Thereby, a texanol solution of (meth) acrylic resin (Poly (BMA / MMA)) having an amide group at the molecular end was obtained.
The obtained polymer was analyzed by gel permeation chromatography using column LF-804 (manufactured by Showa Denko KK) as the column, and the weight average molecular weight in terms of polystyrene was 40,000.

(Polymerization Example 3)
100 parts by weight of a mixed solution of butyl methacrylate and hydroxyethyl methacrylate (BMA / HEMA = 9/1) in an 2 L separatory flask equipped with a stirrer, a cooler, a thermometer, an oil bath, and a nitrogen gas inlet, an organic solvent As a mixture, 100 parts by weight of terpineol 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 up until the oil bath reached 130 ° C. while stirring. . A solution in which azobisisobutyronitrile was dispersed with terpineol as a polymerization initiator was added. Further, a terpineol solution containing a polymerization initiator was added several times during the polymerization, and 0.8 parts by weight of the polymerization initiator was added to 100 parts by weight of the monomer in total.

Seven hours after the start of polymerization, the reaction solution was cooled to room temperature to complete the polymerization. A terpineol solution of (meth) acrylic resin (Poly (BMA / HEMA)) having an isobutyronitrile group was obtained.
The obtained polymer was analyzed by gel permeation chromatography using column LF-804 (manufactured by Showa Denko KK) as the column, and the weight average molecular weight in terms of polystyrene was 140,000.

(Polymerization example 4)
In a 2 L separate flask equipped with a stirrer, a cooler, a thermometer, an oil bath, and a nitrogen gas inlet, a mixed solution of butyl methacrylate, methyl methacrylate, and hydroxyethyl methacrylate (BMA / MMA / HEMA = 4/4/2) ) 100 parts by weight and 100 parts by weight of terpineol as an organic solvent were 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 up until the oil bath reached 130 ° C. while stirring. . A solution in which azobisisobutyronitrile was dispersed with terpineol as a polymerization initiator was added. Further, a terpineol solution containing a polymerization initiator was added several times during the polymerization, and 1.5 parts by weight of the polymerization initiator was added to 100 parts by weight of the monomer in total.

Seven hours after the start of polymerization, the reaction solution was cooled to room temperature to complete the polymerization. This obtained the terpineol solution of the (meth) acrylic resin (Poly (BMA / MMA / HEMA)) which has an amide group in a molecule terminal. The obtained polymer was analyzed by gel permeation chromatography using column LF-804 (manufactured by Showa Denko KK) as a column, and the weight average molecular weight in terms of polystyrene was 50,000.

(Polymerization Example 5)
In a 2 L separate flask equipped with a stirrer, cooler, thermometer, hot water bath and nitrogen gas inlet, a mixture of cyclohexyl methacrylate, methyl methacrylate and hydroxyethyl methacrylate (CHMA / MMA / HEMA = 4/5) / 1) 100 parts by weight, 0.2 parts by weight of mercaptopropanediol as a chain transfer agent, and 100 parts by weight of terpineol as an organic solvent were 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 in the separable flask system was replaced with nitrogen gas and heated until the water bath boiled while stirring. As a polymerization initiator, 0.1 part by weight of an organic oxide polymerization catalyst (Perloyl 355, manufactured by NOF Corporation) was added, a polymerization initiator was added several times during the polymerization, and the total was 100 parts by weight of the monomer. 1.5 parts by weight of a polymerization initiator was added.

Seven hours after the start of polymerization, the reaction solution was cooled to room temperature to complete the polymerization. This obtained the terpineol solution of the (meth) acrylic resin (Poly (CHMA / MMA / HEMA)) which has a hydroxyl group in the molecule terminal. The obtained polymer was analyzed by gel permeation chromatography using column LF-804 (manufactured by Showa Denko KK) as a column, and the weight average molecular weight in terms of polystyrene was 50,000.

(Polymerization Example 6)
Texanol was used instead of terpineol in Polymerization Example 5, and a texanol solution of (meth) acrylic resin (Poly (CHMA / MMA / HEMA)) having a hydroxyl group at the molecular end was obtained in the same manner as in Polymerization Example 5. The obtained polymer was analyzed by gel permeation chromatography using column LF-804 (manufactured by Showa Denko KK) as a column, and the weight average molecular weight in terms of polystyrene was 80,000.

Example 1
Ethylcellulose STD4 was dissolved in terpineol. To this terpineol solution, 1,6-hexanediol was added as an organic compound so that the composition ratio shown in Table 1 was obtained, and a vehicle composition was obtained.

With respect to the obtained vehicle composition, BL-4.2 (manufactured by Nikko Chemical Co., Ltd.) as a nonionic surfactant, glass fine particles having an average particle size of 2.0 μm as inorganic fine particles (SiO ₂ 32.5%, B ₂ O ₃ and 20.5% ZnO and 18% _Al 2 _{O 3} 10%, 3.5% and BaO, 9% of Li ₂ O, 6% of Na ₂ O, the SnO ₂ 0.5% Content) was added so as to have the composition ratio shown in Table 1, and then sufficiently kneaded using a high-speed stirrer and processed until it became smooth with a three-roll mill to prepare an inorganic fine particle-dispersed paste.

(Example 2)
Dispersion of inorganic fine particles in the same manner as in Example 1, except that ethylcellulose STD45 was used instead of ethylcellulose STD4, myristyl alcohol was used instead of 1,6-hexanediol as the organic compound, and the composition ratio was changed to the composition shown in Table 1. A paste was prepared.

(Example 3)
Except that the texanol solution of (meth) acrylic resin (Poly (IBMA)) obtained in Polymerization Example 1 was used instead of the terpineol solution of ethyl cellulose STD4, the composition ratio was changed to the composition ratio shown in Table 1, and the same as in Example 1 Thus, an inorganic fine particle-dispersed paste was prepared.

Example 4
Example 1 except that the texanol solution of (meth) acrylic resin (Poly (BMA / MMA)) obtained in Polymerization Example 2 was used instead of the terpineol solution of ethyl cellulose STD4 and the composition ratio was changed to that shown in Table 1. In the same manner, an inorganic fine particle dispersed paste was prepared.

(Example 5)
(Synthesis of polyvinyl acetal resin)
193 g of polyvinyl alcohol having a polymerization degree of 1700 and a saponification degree of 98 mol% was added to 2900 g of pure water and stirred at a temperature of 90 ° C. for about 2 hours for dissolution.
This solution is cooled to 40 ° C., 20 g of hydrochloric acid having a concentration of 35% by weight and 145 g of n-butyraldehyde are added thereto, the temperature of the solution is lowered to 15 ° C., and this temperature is maintained to conduct an acetalization reaction. The product was precipitated.
Thereafter, the liquid temperature was kept at 40 ° C. for 3 hours to complete the reaction, and neutralized, washed with water and dried by a conventional method to obtain a white powder of polyvinyl acetal resin.
The obtained polyvinyl acetal resin was dissolved in DMSO-d ₆ (dimethyl sulfoxide), and the degree of acetalization was measured using ¹³ C-NMR (nuclear magnetic resonance spectrum). The degree of acetalization was 78 mol%. there were.

5 parts by weight of the obtained polyvinyl butyral resin is added to a mixed solvent of 22 parts by weight of toluene and 11 parts by weight of ethanol, dissolved by stirring, and further 2 parts by weight of dibutyl phthalate as a plasticizer and 2,2-dimethyl as an organic compound. 1,3-propanediol was added so as to have the composition ratio shown in Table 1, and dissolved by stirring. 50 parts by weight of barium titanate (“BT-01 (average particle size: 0.3 μm)” manufactured by Sakai Chemical Industry Co., Ltd.) as ceramic powder is added to the obtained resin solution, and mixed for 48 hours with a ball mill to prepare an inorganic fine particle dispersed paste. A composition was prepared.

(Example 6)
To the terpineol solution of the (meth) acrylic resin (Poly (BMA / HEMA)) obtained in Polymerization Example 3, terpineol was added and dissolved so as to have the composition ratio described in Table 1. To this, 2,2-dimethyl-1,3-propanediol as an organic compound was further added so as to have the composition ratio shown in Table 1, and dispersed with a high-speed disperser.
Further, aluminum fine particles (average particle size of 5 μm) as conductive fine particles and low melting point glass fine particles (average particle size of 1 μm) enabling fire-through are added so as to have the composition ratio shown in Table 1, and a high-speed stirring device is added. After using and kneading sufficiently, treatment was performed with a three roll mill while paying attention not to flatten the aluminum fine particles, and a conductive fine particle dispersed paste was prepared.

(Example 7)
Using a solution obtained by dissolving ethyl cellulose STD4 in terpineol and a terpineol solution of (meth) acrylic resin (Poly (BMA / MMA / HEMA)) obtained in Polymerization Example 4 so as to have the composition ratio described in Table 1. An inorganic fine particle-dispersed paste was produced in the same manner as in Example 1 except that the change was made.

(Example 8)
A terpineol solution of (meth) acrylic resin (Poly (CHMA / MMA / HEMA)) obtained in Polymerization Example 5, a rosin compound (KR85, manufactured by Arakawa Chemical Co., Ltd.), and green phosphor for PDP (Zn ₂ SiO) as inorganic fine particles ₄ ; Mn, manufactured by Nichia Corporation), an inorganic fine particle-dispersed paste was prepared in the same manner as in Example 1 except that the composition ratio was changed to the composition ratio shown in Table 1.

Example 9
Table using a texanol solution of (meth) acrylic resin (Poly (CHMA / MMA / HEMA)) obtained in Polymerization Example 6, ethyl cellulose (STD7), and silver powder (particle size 2 μm, manufactured by Shoei Chemical Co., Ltd.) as inorganic fine particles. An inorganic fine particle-dispersed paste was prepared in the same manner as in Example 1 except that the composition ratio was changed to the composition ratio described in 1.

(Comparative Example 1)
An inorganic fine particle-dispersed paste was prepared in the same manner as in Example 1 except that 1,6-hexanediol as an organic compound was not used and the composition ratio was changed to those shown in Table 1.

(Comparative Example 2)
An inorganic fine particle-dispersed paste was prepared in the same manner as in Example 3 except that 1,6-hexanediol as the organic compound was not used and the composition ratio was changed as shown in Table 1.

(Comparative Example 3)
An inorganic fine particle-dispersed paste was prepared in the same manner as in Example 6 except that 2,2-dimethyl-1,3-propanediol as an organic compound was not used and the composition ratio was changed as shown in Table 1.

(Comparative Example 4)
Instead of 2,2-dimethyl-1,3-propanediol, which is an organic compound, the same as in Example 5 except that pentaerythritol having a hydroxyl group and solid at room temperature but having a boiling point of 300 ° C. or higher was used. Thus, an inorganic fine particle-dispersed paste was prepared.

(Comparative Example 5)
Instead of the organic compound 2,2-dimethyl-1,3-propanediol, the same procedure as in Example 6 was used, except that 2-methyl-1,3-propanediol having a hydroxyl group and a liquid at room temperature was used. Thus, an inorganic fine particle dispersed paste was prepared.

(Comparative Example 6)
Instead of the organic compound 2,2-dimethyl-1,3-propanediol, the same procedure as in Example 8 was used, except that 2-methyl-1,3-propanediol having a hydroxyl group and a liquid at room temperature was used. Thus, an inorganic fine particle dispersed paste was prepared.

(Comparative Example 7)
Instead of the organic compound 2,2-dimethyl-1,3-propanediol, the same procedure as in Example 9 was used, except that 2-methyl-1,3-propanediol having a hydroxyl group and a liquid at room temperature was used. Thus, an inorganic fine particle dispersed paste was prepared.

<Evaluation>
The following evaluation was performed about the inorganic fine particle dispersion | distribution paste obtained by the Example and the comparative example. The results are shown in Table 2.

(1) Using an applicator set to sinterability of 5 mils, the inorganic fine particle dispersed paste was coated on a glass substrate, dried in a blow oven at 150 ° C. for 30 minutes, and then in an electric furnace at 500 ° C. for 30 minutes. Baked. About the obtained sintered layer, residual carbon (ppm) was measured with a carbon sulfur analyzer (manufactured by Horiba Ltd.), and the baked color was visually confirmed. The case where the residual carbon was 150 ppm or less was evaluated as “◯”, and the case where the residual carbon exceeded 150 ppm was evaluated as “X”.

(2) Surface smoothness Using an applicator set to 5 mils, the inorganic fine particle-dispersed paste was coated on a glass substrate and dried in a 150 ° C. blowing oven for 30 minutes. About the obtained inorganic fine particle dispersion paste coating layer, the centerline average roughness (Ra) of the surface was measured by a method based on JIS B 0601, and the case where Ra is 1.0 μm or less is “◯”, 1.0 μm The surface smoothness was evaluated as “x” when exceeding. A stylus roughness meter (manufactured by Tokyo Seimitsu Co., Ltd., Surfcom 1400D) was used for the measurement.
The inorganic fine particle dispersed paste obtained in Comparative Example 2 had a high viscosity, and the coating layer obtained by applying the inorganic fine particle dispersed paste showed fluctuations in the film thickness.

(3) In Examples 8 and 9 and Comparative Examples 6 and 7, using a slit-shaped screen printing plate having a non-sag drying emulsion thickness of 20 μm, stainless mesh # 300, emulsion opening line width of 100 μm, and space of 300 μm. The obtained inorganic fine particle-dispersed paste was printed on a glass substrate and dried in a blown oven set at 120 ° C. for 20 minutes.
Then, the height of the printed shape was evaluated using a laser microscope.
The case where the height of the printed shape after drying was 10 μm or more was designated as “◯”, and the case where the height of the printed shape was less than 10 μm due to sagging during drying was designated as “X”.

Claims

An inorganic fine particle-dispersed paste containing at least one selected from the group consisting of ethyl cellulose, (meth) acrylic resin and polyvinyl acetal resin, an organic compound, inorganic fine particles, and an organic solvent,
The organic compound has one or more hydroxyl groups, is solid at room temperature, and has a boiling point of less than 300 ° C.
The inorganic fine particle-dispersed paste according to claim 1, wherein the inorganic fine particles are at least one selected from the group consisting of lead-free glass fine particles, ceramic fine particles, and aluminum fine particles.
A glass dielectric produced by using the inorganic fine particle dispersed paste according to claim 1.
A ceramic green sheet produced using the inorganic fine particle dispersed paste according to claim 1.
A solar battery cell produced using the inorganic fine particle dispersed paste according to claim 1.
A flat panel display manufactured using the inorganic fine particle-dispersed paste according to claim 1.