TWI483977B - Inorganic fine particle dispersion paste - Google Patents

Description

Inorganic microparticle dispersion paste

The present invention relates to an inorganic fine particle-dispersed paste which can form a sintered layer excellent in surface smoothness.

In recent years, in order to obtain a sintered body of various shapes, an inorganic fine particle-dispersed paste obtained by dispersing inorganic fine particles such as conductive powder or ceramic powder in a binder resin has been used. In particular, a phosphor paste obtained by dispersing a phosphor in an adhesive resin as an inorganic fine particle or a glass paste in which a low-melting glass is dispersed is applied to a plasma display panel or the like, and demand has been increasing in recent years.

Further, a ceramic paste obtained by dispersing barium titanate or aluminum oxide as an inorganic fine particle in a binder resin is molded into a green sheet, and is used for a laminated electronic component such as a laminated ceramic capacitor.

Further, the back electrode of the solar cell panel is usually formed by coating a paste in which aluminum powder is dispersed by screen printing or the like, drying it, and then calcining it.

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

Patent Document 1 discloses that in the composition for a dielectric layer disclosed in the document, the dispersion state of the glass frit is effectively improved.

In order to form a uniform sintered layer, the characteristics of the sintered layer are not deviated, and the improvement of the dispersibility of the inorganic fine particles as described above is important. However, since the sintered layer can be formed by the printing, drying, degreasing, and calcining steps of the inorganic fine particle dispersion paste, it is difficult to sufficiently improve the uniformity of the paste state, that is, the dispersibility of the inorganic fine particles, to sufficiently ensure the uniformity of the finally formed sintered layer. .

Further, as in the green sheet disclosed in Patent Document 1, the inorganic fine particle-dispersed paste was previously processed into a sheet shape, and the obtained green sheet was used to form a uniform sintered layer. However, in the case of using a green sheet, there was a green sheet pair. The problem of insufficient adhesion of the substrate.

Patent Document 1: Japanese Patent Laid-Open Publication No. 2004-002164

An object of the present invention is to provide an inorganic fine particle-dispersed paste which can form a sintered layer excellent in surface smoothness.

The present invention is an inorganic fine particle-dispersed paste comprising: 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 and is solid at normal temperature and has a boiling point of less than 300 °C.

The invention is described in detail below.

Usually, a high boiling point solvent is used in the inorganic fine particle dispersion paste for forming a sintered layer to ensure printability. Further, in order to efficiently dry the high-boiling solvent to improve the productivity, the air blowing oven is used in the drying step after printing. The present inventors have found that the air blow in the oven causes surface roughness of the coating layer of the inorganic fine particle-dispersed paste, and as a result, the surface smoothness of the sintered layer is lowered, and the performance of the sintered layer is deteriorated.

The present inventors have found that at least one selected from the group consisting of ethyl cellulose, (meth)acrylic resin, and polyvinyl acetal resin, inorganic fine particles, and an organic solvent further contain one or more hydroxyl groups. And the inorganic fine particle dispersion paste which is solid at normal temperature and the organic compound having a boiling point lower than 300 ° C can be well dried in the drying step after printing, and can be inhibited from being blown in the oven when dried in an oven. The surface is rough and does not cause uniform drying due to skinning caused by cross-linking of the resin. Furthermore, the present inventors have found that the sintered layer formed using the inorganic fine particle-dispersed paste has excellent surface smoothness, and 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 may be appropriately selected depending on the printing method of the obtained inorganic fine particle-dispersed paste, the thickness of the target sintered layer, and the like. Among them, in the case of screen printing, ethyl cellulose having thixotropic properties is usually preferred, and ethyl cellulose grades such as STD 45 and STD 100 are preferred. Further, in the case where a thick sintered layer is to be obtained, 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 is liable to become high, so that it is preferably a low-viscosity specification such as STD4 or STD10. Grade ethyl cellulose.

The (meth)acrylic resin is not particularly limited as long as it can be decomposed at a low temperature of about 350 to 400 ° C, and is preferably a polymer composed of at least one selected from the group consisting of the following compounds, that is, : (methyl) methacrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, (meth) acrylate Butyl ester, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isobornyl (meth)acrylate, n-stearyl (meth)acrylate, benzyl (meth)acrylate An ester and a (meth)acrylic monomer having a polyoxyalkylene structure. Here, for example, (meth) acrylate means acrylate or methacrylate.

Among them, polymethyl methacrylate (polymer of methacrylate having a Tg of 105 ° C) having a high glass transition temperature (Tg) is preferred because a higher viscosity can be obtained with a smaller amount of resin. . Moreover, polymethacrylate is also excellent in low-temperature degreasing property. Further, since the inorganic fine particle-dispersed paste of the present invention contains an organic compound described later, the (meth)acrylic resin is preferably a polymer containing a component derived from butyl methacrylate or isobutyl methacrylate.

Further, the (meth)acrylic resin may further contain a fragment composed of a monomer having a polar group.

Examples of the monomer having a polar group include 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, methacrylic acid, glycidyl methacrylate, and glycerin monomethacrylate.

In the case of containing a fragment derived from the above-mentioned monomer having a polar group, the content of the fragment derived from the monomer having a polar group is preferably 20% by weight or less.

When the content of the fragment derived from the monomer having a polar group exceeds 20% by weight, the thermal decomposition property at a low temperature may be impaired, or the amount of coal ash adhering to the inorganic fine particles may increase, or the residual carbon of the sintered body may increase. . The above content is more preferably 10 parts by weight or less.

The above (meth)acrylic resin preferably has a hydrophilic functional group at the molecular terminal. The hydrophilic functional group is not particularly limited, and is preferably a carbonyl group, an amine group or a guanamine group.

In general, when a (meth)acrylic resin having a functional group having a high interaction such as a carbonyl group, an amine group or a guanamine group is introduced onto an ester substituent of a (meth)acrylic monomer, the inorganic In the calcination step of the fine particle-dispersed paste, the depolymerization of the (meth)acrylic resin is hindered, and the thermal decomposition end temperature is increased, and the thermal decomposition property is seriously deteriorated.

On the other hand, when it is used in the case of a (meth)acrylic resin having a carbonyl group, an amine group, a guanamine group or the like at the molecular terminal, the depolymerization of the (meth)acrylic resin is not hindered, and the heat is hardly affected. Decompose the end temperature. In addition, since inorganic microparticles such as glass powder have high interaction with a carbonyl group, an amine group, a guanamine group, etc., when it is used for a (meth)acrylic resin having a carbonyl group, an amine group or a guanamine group at the molecular terminal. The molecular end of the (meth)acrylic resin is adsorbed on the surface of the inorganic fine particles, and the other molecular end is extended toward the organic solvent side, thereby preventing the inorganic fine particles from re-agglomerating and improving the dispersion stability.

The weight average molecular weight of the (meth)acrylic resin converted from polystyrene is not particularly limited, and a preferred lower limit is 5,000, and a preferred upper limit is 500,000. When the weight average molecular weight is less than 5,000, the obtained inorganic fine particle-dispersed paste may not have sufficient viscosity, and the screen printing property may be deteriorated, and in some cases, in the drying step after printing, air may be blown in the oven. The surface roughness is increased, whereby the surface smoothness of the sintered layer is lowered. When the weight average molecular weight exceeds 500,000, the adhesion of the obtained inorganic fine particle-dispersed paste becomes too high, and wire drawing may occur, resulting in deterioration of screen printing property. A preferred upper limit of the above weight average molecular weight is 100,000, and a more preferred upper limit is 50,000. In particular, when the weight average molecular weight of the (meth)acrylic resin derived from polystyrene is 10,000 to 50,000, a clear image can be obtained at the time of screen printing, which is preferable.

In addition, the weight average molecular weight obtained by the polystyrene conversion can be obtained by GPC (gel permeation chromatography) measurement using, for example, Column LF-804 (manufactured by Showa Denko Co., Ltd.) as a column.

The method for producing the above (meth)acrylic resin is not particularly limited, and examples thereof include a radical polymerization method and a living radical polymerization method in the presence of a polymerization initiator having a carbonyl group, an amine group or a guanamine group. a method of copolymerizing the above (meth)acrylic monomer by a conventionally known method such as a transfer terminator polymerization method, an anionic polymerization method, or an living anionic polymerization method; or a carbonyl group, an amine group, a guanamine group, or the like In the presence of a chain transfer agent, the above (meth)acrylic monomer is obtained by a conventionally known method such as a radical polymerization method, a living radical polymerization method, an initiating transfer terminator polymerization method, an anionic polymerization method, or a living anionic polymerization method. A method of performing copolymerization or the like. These methods may be used singly or in combination of two or more.

In the above method for producing a (meth)acrylic resin, a carbonyl group or an amine can be introduced at a more molecular end by using a polymerization initiator having a carbonyl group, an amine group, a guanamine group or the like as a radical polymerization initiator. Base, amidino group and the like. Further, for example, it can be confirmed by ¹³ C-NMR that a carbonyl group, an amine group, a guanamine group or the like is introduced only at the molecular terminal of the above (meth)acrylic resin.

The polyvinyl acetal resin is not particularly limited as long as it has excellent compatibility with an organic solvent to be described later, and is preferably obtained by acetalizing a polyvinyl alcohol resin having a degree of saponification of 80 mol% or more, and a degree of polymerization. A polyvinyl acetal resin having a degree of acetalization of from 60 to 80 mol%, from 1,000 to 4,000.

The degree of saponification of the above polyvinyl alcohol is preferably 80 mol% or more. When the degree of saponification is less than 80 mol%, the solubility of polyvinyl alcohol in water is deteriorated, so that it is difficult to carry out the acetalization reaction, and if the amount of the hydroxyl group is small, the acetalization reaction itself may become difficult.

The degree of polymerization of the above polyvinyl alcohol is preferably from 1,000 to 4,000.

When the degree of polymerization is less than 1,000, for example, when it is used as a material for a ceramic green sheet, the strength may become insufficient. When the degree of polymerization exceeds 4,000, the solubility in water may decrease, or the viscosity of the aqueous solution may become high, and acetalization may be difficult. Moreover, if the viscosity of the solution becomes too high, the coatability is lowered.

Further, the degree of polymerization of the polyvinyl acetal is a degree of polymerization of polyvinyl alcohol which is a raw material at the time of synthesis. Further, in the case of mixing two or more kinds of polyvinyl alcohols, the average value of the polymerization degrees thereof is used.

The above polyvinyl alcohol is obtained by saponifying a polymer of a vinyl ester.

Examples of the vinyl ester include vinyl formate, vinyl acetate, vinyl propionate, and trimethyl vinyl acetate. From the viewpoint of economy, vinyl acetate is preferred.

Further, the polyvinyl alcohol preferably contains an α-olefin in the main chain.

The hydrogen bonding force of the polyvinyl acetal resin is weakened by the presence of the above α-olefin, so that the stability of the viscosity can be improved over time, or the screen printing property can be improved.

Examples of the α-olefin include, for example, methylene, ethylene, propylene, isopropylene, butylene, isobutylene, pentene, hexene, cyclohexene, cyclohexylethylene, and cyclohexylpropene.

The content of the above α-olefin is preferably from 1 to 20 mol%.

If the content of the above α-olefin is less than 1 mol%, the properties of the obtained polyvinyl acetal resin are not changed as compared with the unmodified polyethylene acetal resin, and if it exceeds 20 mol%, sometimes Since the solubility of polyvinyl alcohol in water is lowered, it becomes difficult to carry out an acetalization reaction, or the hydrophobicity of the formed polyvinyl acetal resin becomes too strong, and solubility in an organic solvent falls.

The above polyvinyl alcohol may also be copolymerized with other ethylenically unsaturated monomers within a range that does not impair the effects of the present invention.

Examples of such an ethylenically unsaturated monomer include acrylic acid, methacrylic acid, phthalic acid (anhydride), maleic acid (anhydride), itaconic acid (anhydride), acrylonitrile, and methacryl. Nitrile, acrylamide, methacrylamide, (3-propenylamine-3-dimethylpropyl)trimethylammonium chloride, acrylamide-2-methylpropanesulfonic acid and sodium salt thereof, Ethyl vinyl ether, butyl vinyl ether, N-vinyl pyrrolidone, vinyl chloride, vinyl bromide, vinyl fluoride, vinylidene chloride, vinylidene fluoride, tetrafluoroethylene, sodium vinyl sulfonate, olefin Sodium propyl sulfonate and the like.

Further, it is also possible to use a terminal modified polycondensation obtained by copolymerizing a vinyl ester monomer such as vinyl acetate with ethylene in the presence of a thiol compound such as thioacetic acid or mercaptopropionic acid, and saponifying it. Vinyl alcohol.

The aldehyde to be used in the above reaction is not particularly limited, and examples thereof include formaldehyde (including trioxane), acetaldehyde (including paraldehyde), propionaldehyde, butyraldehyde, valeraldehyde, hexanal, heptaldehyde, and 2 -ethylhexanal, cyclohexanal, furfural, glyoxal, glutaraldehyde, benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxyaldehyde, m-hydroxyl Aldehyde, phenylacetaldehyde, phenylpropanal, and the like.

These aldehydes may be used singly or in combination of two or more kinds, and it is suitable to use acetaldehyde and/or butyraldehyde.

The polyvinyl acetal resin can be obtained by dissolving a polyvinyl alcohol resin in warm water and then adding an aldehyde to a predetermined degree of acetalization in the presence of an acid catalyst, and then reacting the aldehyde. Wash, neutralize, and dry.

The acid catalyst is not particularly limited, and any of an organic acid and an inorganic acid may be used. Examples thereof include acetic acid, p-toluenesulfonic acid, nitric acid, sulfuric acid, and hydrochloric acid.

Further, examples of the base to be used for the neutralization include sodium hydroxide, potassium hydroxide, ammonia, sodium acetate, sodium carbonate, sodium hydrogencarbonate, and potassium carbonate.

The degree of acetalization of the polyvinyl acetal resin used in the present invention is preferably from 60 to 80 mol%. When the degree of acetalization is less than 60 mol%, the hydrogen bonding property of the polyvinyl acetal resin may become too strong, and sufficient screen printing properties may not be obtained.

On the other hand, the above polyvinyl acetal resin having a degree of acetalization of more than 80 mol% is generally industrially difficult to manufacture. (The maximum degree of acetalization is preferably 81.6 mol% according to the theory of P. J. 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, and a preferred lower limit is 5 weights. %, a 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 obtained inorganic fine particle-dispersed paste may not obtain sufficient viscosity. The screen printing property is deteriorated, and in some cases, in the drying step after printing, the surface roughness due to the air blowing in the oven is increased, whereby the surface smoothness of the sintered layer is lowered. When the content is more than 25% by weight, the viscosity and adhesion of the obtained inorganic fine particle-dispersed paste may become too high, and the screen printing property may be deteriorated.

The inorganic fine particle-dispersed paste of the present invention contains an organic compound having one or more hydroxyl groups and being solid at normal temperature and having a boiling point of lower than 300 °C.

The above organic compound is a solid at normal temperature. By making the organic compound solid at normal temperature, the obtained inorganic fine particle-dispersed paste can be suppressed from being roughened by air blowing in an oven in the drying step after printing, and the surface smoothness of the sintered layer is excellent.

In addition, the organic compound is solid at normal temperature, but can be obtained by dissolving in an organic solvent to be described later to obtain a paste-like inorganic fine particle-dispersed paste.

Further, the above organic compound is different from the organic solvent described later.

The mechanism for improving the drying property by adding the above-described organic compound having one or more hydroxyl groups and being solid at normal temperature and having a boiling point of lower than 300 ° C can be considered as follows.

The surface of the inorganic fine particles added to the inorganic fine particle-dispersed paste has a very high polarity and has a function of attracting a highly polar functional group. In the case where an organic material having a functional group having a high polarity is not normally added to the inorganic fine particle-dispersed paste, the fine particles in the solvent aggregate with each other to cause precipitation.

Therefore, when an organic compound having one or more hydroxyl groups and having a solid at normal temperature and having a boiling point of less than 300 ° C is added, the organic compound is mixed with an organic solvent in an inorganic fine particle-dispersing paste to form a liquid, and thus it is preferred Adsorbed on the surface of the inorganic fine particles to form a layer which can be evaporated around the inorganic fine particles under dry conditions.

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 used under dry conditions. The surface of the inorganic fine particle-dispersed paste is gradually dried, and the surface is crusted to form a thin resin layer.

Such a surface resin layer formed in association with drying is very uneven, and depending on the drying conditions, a more uneven layer is formed under strong drying conditions under air blowing conditions. Therefore, the organic solvent existing under the resin layer of the crust is difficult to evaporate, and it is easy to cause irregularities on the surface of the coating film.

On the other hand, the organic compound which forms a layer on the surface of the inorganic fine particles is evaporated under dry conditions to form a window for evaporating the internal organic solvent. Therefore, drying unevenness of the organic solvent due to resin crust can be reduced. Further, even when the drying is insufficient, the organic compound is solid at normal temperature, so that it does not easily function as a plasticizer, and it is easy to maintain smoothness.

The above organic compound has a boiling point of less than 300 °C. When the boiling point of the organic compound is 300 ° C or more, the drying property of the obtained inorganic fine particle-dispersed paste in the drying step after printing is lowered, and the surface smoothness of the sintered layer is lowered. The above organic compound preferably has a boiling point of less than 280 ° C, more preferably less than 260 ° C.

Further, the lower limit of the boiling point of the above organic compound is not particularly limited, but the boiling point is preferably 160 ° C or higher. When the boiling point of the above organic compound is less than 160 ° C, the obtained inorganic fine particle-dispersed paste is easily dried during the printing process, and may cause a problem in the case of continuous printing for a long period of time. Further, the above boiling point means the boiling point at normal pressure.

The above organic compound has one or more hydroxyl groups. By having one or more of the above hydroxyl groups, the storage stability of the obtained inorganic fine particle-dispersed paste can be improved, and the viscosity of the inorganic fine particle-dispersed paste can be improved by the interaction of the hydroxyl group with the resin and the organic solvent, thereby obtaining a suitable viscosity. Viscosity in screen printing, etc.

The organic compound is not particularly limited as long as it has one or more hydroxyl groups and is solid at normal temperature, and has a boiling point of less than 300 ° C. It is preferably an alcohol-based organic compound composed of an aliphatic chain having a carbon number of 5 or more and less than 20. .

The alcohol-based organic compound is not particularly limited, and examples thereof include 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, myristyl alcohol, cetyl alcohol, and 2,2- Dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, trimethylolpropane, pentaerythritol, and the like.

Among them, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-, which have a higher ratio of hydroxyl groups to carbon numbers Since 1,3-propanediol 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 in screen printing.

The content of the above organic compound in the inorganic fine particle-dispersed paste of the present invention is not particularly limited, and a preferred lower limit is 1% by weight, and a preferred upper limit is 30% by weight. When the content of the above organic compound is less than 1% by weight, the obtained inorganic fine particle-dispersed paste may have a decrease in drying property in a drying step after printing, or an increase in surface roughness due to air blowing in an oven, or a resin due to a resin. The skinning phenomenon caused by crosslinking causes the surface smoothness of the sintered layer to decrease. When the content of the above organic compound exceeds 30% by weight, the storage stability of the obtained inorganic fine particle-dispersed paste may be deteriorated.

The inorganic fine particle-dispersed paste of the present invention contains an organic solvent.

The organic solvent is not particularly limited, and examples thereof include ethylene glycol diethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, and diethyl ether. Glycol monoisobutyl ether, trimethyl pentanediol monoisobutyrate, butyl carbitol, butyl carbitol acetate, Texanol, isophorone, butyl lactate, phthalic acid Octyl ester, dioctyl adipate, benzyl alcohol, phenylpropanediol, cresol, rosinol, rosinol acetate, dihydroterpineol, dihydroterpineol acetate, acetone, methyl ethyl ketone, Methanol, ethanol, n-propanol, isopropanol, n-butanol, toluene, xylene, and the like. These organic solvents may be used singly or in combination of two or more.

The content of the above organic solvent in the inorganic fine particle-dispersed paste of the present invention is not particularly limited, and 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 force of the obtained inorganic fine particle-dispersed paste may become too high, and the screen printing property may be deteriorated. When the content of the organic solvent exceeds 60% by weight, the obtained inorganic fine particle-dispersed paste may not have sufficient viscosity, and the screen printing property may be deteriorated, and the drying property may be lowered in the drying step after printing, or The surface roughness caused by the air supply in the oven is increased, whereby the surface smoothness of the sintered layer is lowered.

In the case where the inorganic fine particle-dispersed paste of the present invention is calcined, it is preferred to carry out calcination in a state where the organic solvent or the organic compound has been dried. When the organic solvent or the organic compound is not sufficiently dried and is calcined in an organic solvent or an organic compound, the coal ash generated by thermal decomposition of the binder resin is easily adsorbed on the surface of the fine particles, so that it is compared with the case of completely drying. Sometimes carbon residue is likely to increase.

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, cerium oxide, metal fine particles, and metal oxide fine particles.

The glass powder is not particularly limited, and examples thereof include glass powders such as cerium oxide glass, strontium silicate glass, lead glass, zinc glass, and borosilicate, or CaO-Al ₂ O ₃ —SiO ₂ system, and MgO-Al _{2 .} A glass powder of various cerium oxides such as O ₃ -SiO ₂ -based or LiO ₂ -Al ₂ O ₃ -SiO ₂ -based.

Further, as the glass powder, a PbO-B ₂ O ₃ -SiO ₂ mixture, a BaO-ZnO-B ₂ O ₃ -SiO ₂ mixture, and a ZnO-Bi ₂ O ₃ -B ₂ O ₃ -SiO ₂ mixture may also be used. , 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-R 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 A glass powder such as a BaO-ZnO-B ₂ O ₃ -SiO ₂ mixture. Further, R is an element selected from the group consisting of Zn, Ba, Ca, Mg, Sr, Sn, Ni, Fe, and Mn.

Particularly preferred is a glass powder of a PbO-B ₂ O ₃ -SiO ₂ mixture, or a lead-free BaO-ZnO-B ₂ O ₃ -SiO ₂ mixture or a ZnO-Bi ₂ O ₃ -B ₂ O ₃ -SiO ₂ mixture Lead-free glass powder.

The ceramic powder is not particularly limited, and examples thereof include alumina, zirconia, titania, barium titanate, aluminum oxynitride, tantalum nitride, and boron nitride.

Further, nano ITO (Indium Tin Oxide) used in a transparent electrode material or nano titanium oxide used in a dye-sensitized solar cell can be suitably used.

The phosphor fine particles are not particularly limited, and examples thereof include BaMgAl ₁₀ O ₁₇ :Eu, Zn ₂ SiO ₄ :Mn, and (Y,Gd)BO ₃ :Eu.

The metal fine particles are not particularly limited, and examples thereof include powders composed of nickel, palladium, platinum, gold, silver, aluminum, tungsten, or the like.

Further, a metal such as copper or iron which is excellent in adsorption characteristics such as a carboxyl group, an amine group or a guanamine group and which is easily oxidized can be suitably used. These metal powders may be used singly or in combination of two or more.

The content of the inorganic fine particles in the inorganic fine particle-dispersed paste of the present invention is not particularly limited, and a preferred lower limit is 20% by weight, and a preferred upper limit is 90% by weight. When the content of the inorganic fine particles is less than 20% by weight, the obtained inorganic fine particle-dispersed paste may not have sufficient viscosity, and the screen printing property may be deteriorated, and in some cases, it may be blown in the oven in the drying step after printing. The resulting surface roughness is increased, whereby the surface smoothness of the sintered layer is lowered. When the content of the inorganic fine particles exceeds 90% by weight, the viscosity of the obtained inorganic fine particle-dispersed paste may become too high, and the screen printing property may be deteriorated.

In order to stabilize the compatibility of the above organic compound with other materials, the inorganic fine particle-dispersed paste of the present invention preferably contains a surfactant. The surfactant is not particularly limited, and is preferably a nonionic surfactant.

The content of the nonionic surfactant in the inorganic fine particle dispersion paste of the present invention is not particularly limited, and a preferred upper limit is 5% by weight. Although the thermal decomposition property of the nonionic surfactant is good, when the content exceeds 5% by weight, the thermal decomposition property of the inorganic fine particle dispersion paste may be lowered.

The method for producing the inorganic fine particle-dispersed paste of the present invention is not particularly limited, and a conventionally known stirring method can be used. Specifically, for example, a three-roll mill or the like is selected from the group consisting of ethyl cellulose and (methyl). And at least one of the group consisting of an acrylic resin and a polyvinyl acetal resin, the organic compound, the organic solvent, the inorganic fine particles and other components added as needed, and the like.

The inorganic fine particle-dispersed paste of the present invention can be well dried in the drying step after printing, and the surface roughness caused by the air supply in the oven is suppressed, and the adverse effect of the skinning phenomenon during drying can be prevented, so that it can be formed. A sintered layer excellent in surface smoothness. For this reason, for example, it is suitably used as a glass paste when glass powder is used as the inorganic fine particles, a ceramic paste when ceramic powder is used as the inorganic fine particles, or a conductive paste when a metal such as aluminum or a conductive powder is used as the inorganic fine particles.

Among them, the glass paste when glass powder is used as the inorganic fine particles is suitable for forming a dielectric layer of a plasma display panel or the like. A glass dielectric manufactured using such a glass paste is also one of the inventions.

Further, the inorganic fine particle-dispersed paste of the present invention has a feature of preventing skinning during drying and drying quickly. Therefore, it can also be suitably used for a member which flows when it is dried when the resin paste is used, and it is difficult to maintain the shape. Moreover, the state in which the shape cannot be maintained in this way is also called "collapse".

For example, when a phosphor in a unit in a back panel of a plasma display or a surface electrode of a solar cell unit is manufactured using a conventional resin paste, collapse occurs during drying, and the height cannot be maintained after printing, but The inorganic fine particle-dispersed paste of the present invention can also be suitably used as a material for a flat panel display by using the inorganic fine particle-dispersed paste of the present invention to remove the organic solvent before the flow is lowered to a low level during the drying process.

A flat panel display manufactured by using the inorganic fine particle dispersion paste of the present invention is also one of the inventions.

According to the present invention, it is possible to provide an inorganic fine particle-dispersed paste capable of forming a sintered layer excellent in surface smoothness.

The invention is further illustrated by the following examples, but the invention is not limited to the examples.

(polymerization example 1)

In a 2 L separable flask equipped with a stirrer, a condenser, a thermometer, an oil bath, and a nitrogen gas inlet, 100 parts by weight of isobutyl methacrylate (IBMA) and 100 parts by weight of Texanol as an organic solvent were mixed. A monomer mixture is obtained.

The obtained monomer mixture was bubbled with nitrogen for 20 minutes to remove dissolved oxygen, and then the inside of the separable flask system was replaced with nitrogen, and the temperature was raised while stirring until the oil bath reached 130 °C. A solution obtained by dispersing 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propanamide] as a polymerization initiator in Texanol was added. Further, a Texanol solution containing a polymerization initiator was added several times during the polymerization, and a total of 1.5 parts by weight of a polymerization initiator was added to 100 parts by weight of the monomer.

After 7 hours from the start of the polymerization, the reaction liquid was cooled to room temperature to complete the polymerization. Thus, a Texanol solution of a (meth)acrylic resin (Poly (IBMA)) having a mercaptoamine group at the molecular end was obtained.

The obtained polymer was analyzed by gel permeation chromatography using Column LF-804 (manufactured by Showa Denko Co., Ltd.) as a column, and the weight average molecular weight converted from polystyrene was 40,000.

(polymerization example 2)

100 parts by weight of a 1:1 mixture of butyl methacrylate and methyl methacrylate (BMA/MMA) in a 2 L separable flask equipped with a stirrer, condenser, thermometer, oil bath and nitrogen inlet. And 100 parts by weight of Texanol as an organic solvent were mixed to obtain a monomer mixture.

The obtained monomer mixture was bubbled with nitrogen for 20 minutes to remove dissolved oxygen, and then the inside of the separable flask system was replaced with nitrogen, and the temperature was raised while stirring until the oil bath reached 130 °C. A solution obtained by dispersing 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propanamide] as a polymerization initiator in Texanol was added. Further, a Texanol solution containing a polymerization initiator was added several times during the polymerization, and a total of 1.5 parts by weight of a polymerization initiator was added to 100 parts by weight of the monomer.

After 7 hours from the start of the polymerization, the reaction liquid was cooled to room temperature to complete the polymerization. Thus, a Texanol solution of a (meth)acrylic resin (Poly (BMA/MMA)) having a mercaptoamine group at the molecular end was obtained.

The obtained polymer was analyzed by gel permeation chromatography using Column LF-804 (manufactured by Showa Denko Co., Ltd.) as a column, and the weight average molecular weight converted from polystyrene was 40,000.

(polymerization example 3)

A mixture of butyl methacrylate and hydroxyethyl methacrylate (BMA/HEMA=9/1) 100 in a 2 L separable flask equipped with a stirrer, condenser, thermometer, oil bath and nitrogen inlet. The monomer mixture was obtained by mixing in parts by weight and 100 parts by weight of rosinol as an organic solvent.

The obtained monomer mixture was bubbled with nitrogen for 20 minutes to remove dissolved oxygen, and then the inside of the separable flask system was replaced with nitrogen, and the temperature was raised while stirring until the oil bath reached 130 °C. A solution obtained by dispersing azobisisobutyronitrile as a polymerization initiator in rosin alcohol was added. Further, a rosin alcohol solution containing a polymerization initiator was added several times during the polymerization, and a polymerization initiator was added in an amount of 0.8 part by weight based on 100 parts by weight of the monomer.

After 7 hours from the start of the polymerization, the reaction liquid was cooled to room temperature to complete the polymerization. A rosin alcohol solution of a (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 Co., Ltd.) as a column, and the weight average molecular weight obtained by polystyrene conversion was 140,000.

(polymerization example 4)

Mixture of butyl methacrylate with methyl methacrylate and hydroxyethyl methacrylate in a 2 L separable flask equipped with a stirrer, condenser, thermometer, oil bath and nitrogen inlet (BMA/MMA) /HEMA = 4 / 4 / 2) 100 parts by weight and 100 parts by weight of rosin alcohol as an organic solvent were mixed to obtain a monomer mixture.

The obtained monomer mixture was bubbled with nitrogen for 20 minutes to remove dissolved oxygen, and then the inside of the separable flask system was replaced with nitrogen, and the temperature was raised while stirring until the oil bath reached 130 °C. A solution obtained by dispersing azobisisobutyronitrile as a polymerization initiator in rosin alcohol was added. Further, a rosin alcohol solution containing a polymerization initiator was added several times during the polymerization, and a total of 1.5 parts by weight of a polymerization initiator was added to 100 parts by weight of the monomer.

After 7 hours from the start of the polymerization, the reaction liquid was cooled to room temperature to complete the polymerization. Thereby, a rosin alcohol solution of a (meth)acrylic resin (Poly (BMA/MMA/HEMA)) having a mercaptoamine group at the molecular end was obtained. The obtained polymer was analyzed by gel permeation chromatography using Column LF-804 (manufactured by Showa Denko Co., Ltd.) as a column, and the weight average molecular weight converted from polystyrene was 50,000.

(polymerization example 5)

Mixture of cyclohexyl methacrylate with methyl methacrylate and hydroxyethyl methacrylate in a 2 L separable flask equipped with a stirrer, condenser, thermometer, hot water bath and nitrogen inlet (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 rosinol as an organic solvent were mixed to obtain a monomer mixture.

The obtained monomer mixture was bubbled with nitrogen for 20 minutes to remove dissolved oxygen, and then the inside of the separable flask system was replaced with nitrogen, and the mixture was heated while stirring until the hot water tank boiled. 0.1 part by weight of an organic oxide polymerization catalyst (Peroyl 355, manufactured by Nippon Oil Co., Ltd.) as a polymerization initiator was added, and a polymerization initiator was added several times during the polymerization, and a total of 100 parts by weight relative to the monomer was added. The total amount is 1.5 parts by weight of a polymerization initiator.

After 7 hours from the start of the polymerization, the reaction liquid was cooled to room temperature to complete the polymerization. Thereby, a rosin alcohol solution of a (meth)acrylic resin (Poly(CHMA/MMA/HEMA)) having a hydroxyl group at the molecular end was obtained. The obtained polymer was analyzed by gel permeation chromatography using Column LF-804 (manufactured by Showa Denko Co., Ltd.) as a column, and the weight average molecular weight converted from polystyrene was 50,000.

(polymerization example 6)

A Texanol solution of a (meth)acrylic resin (Poly (CHMA/MMA/HEMA)) having a hydroxyl group at the molecular terminal was obtained in the same manner as in Polymerization Example 5 except that Texanol was used instead of the rosin alcohol in the polymerization example 5. The obtained polymer was analyzed by gel permeation chromatography using Column LF-804 (manufactured by Showa Denko Co., Ltd.) as a column, and the weight average molecular weight obtained by polystyrene conversion was 80,000.

(Example 1)

Ethylcellulose STD4 was dissolved in rosinol. To the rosin solution, 1,6-hexanediol as an organic compound was added so as to have a composition ratio shown in Table 1, to obtain a vehicle composition.

The obtained vehicle composition was added to BL-4.2 (manufactured by Nikko Chemical Co., Ltd.) as a nonionic surfactant, and the average particle diameter as inorganic fine particles was 2.0 μm so as to achieve the composition ratio shown in Table 1. Glass microparticles (containing 32.5% SiO ₂ , 20.5% B ₂ O ₃ , 18% ZnO, 10% Al ₂ O ₃ , 3.5% BaO, 9% Li ₂ O, 6% Na ₂ O and After 0.5% of SnO ₂ ), the mixture was thoroughly kneaded by a high-speed stirring device, and treated by a three-roll mill until uniformity was obtained to prepare an inorganic fine particle-dispersed paste.

(Example 2)

In the same manner as in Example 1, except that ethyl cellulose STD45 was used instead of ethyl cellulose STD45, and myristyl alcohol was used as the organic compound instead of 1,6-hexanediol, and the composition ratio shown in Table 1 was changed. An inorganic fine particle dispersion paste was prepared.

(Example 3)

A Texanol solution of (meth)acrylic resin (Poly (IBMA)) obtained in Polymerization Example 1 was used instead of the rosin alcohol solution of ethyl cellulose STD4, and was changed to the composition ratio shown in Table 1, and In the same manner as in Example 1, an inorganic fine particle-dispersed paste was produced.

(Example 4)

A Texanol solution of (meth)acrylic resin (Poly (BMA/MMA)) obtained in Polymerization Example 2 was used instead of the rosin alcohol solution of ethyl cellulose STD4, and was changed to the composition ratio shown in Table 1, except In the same manner as in Example 1, an inorganic fine particle-dispersed paste was produced.

(Example 5)

(Synthesis of Polyvinyl Acetal Resin)

193 g of polyvinyl alcohol having a degree of polymerization of 1700 and a degree of saponification of 98 mol% was added to 2900 g of pure water, and the mixture was stirred at a temperature of 90 ° C for about 2 hours to be dissolved.

The solution was cooled to 40 ° C, 20 g of hydrochloric acid having a concentration of 35% by weight and 145 g of n-butyraldehyde were added thereto, and the temperature of the liquid was lowered to 15 ° C, and the temperature was maintained to carry out an acetalization reaction to precipitate a reaction product. .

Thereafter, the liquid temperature was adjusted to 40 ° C for 3 hours to complete the reaction, and the mixture was neutralized, washed with water and dried by a usual method to obtain a white powder of a polyvinyl acetal resin.

The obtained polyvinyl acetal resin was dissolved in DMSO-d ₆ (dimethylammonium), and the degree of acetalization was measured by ¹³ C-NMR (nuclear magnetic resonance spectroscopy), and the degree of acetalization was 78 mol%.

5 parts by weight of the obtained polyvinyl butyral resin was added to a mixed solvent of 22 parts by weight of toluene and 11 parts by weight of ethanol, and the mixture was stirred and dissolved, and further added as a plasticizer so as to have a composition ratio as shown in Table 1. 2 parts by weight of dibutyl phthalate and 2,2-dimethyl-1,3-propanediol as an organic compound were stirred and dissolved. To the obtained resin solution, 50 parts by weight of barium titanate ("BT-01 (average particle diameter: 0.3 μm)"), which is a ceramic powder, was added and mixed by a ball mill for 48 hours to prepare an inorganic fine particle dispersion paste. Composition.

(Example 6)

The rosin alcohol solution of the (meth)acrylic resin (Poly (BMA/HEMA)) obtained in the polymerization example 3 was added to rosin alcohol so as to have a composition ratio shown in Table 1, and dissolved. Further, 2,2-dimethyl-1,3-propanediol as an organic compound was further added so as to have a composition ratio as shown in Table 1, and the mixture was dispersed by a high-speed disperser.

Further, aluminum fine particles (average particle diameter: 5 μm) as conductive fine particles and low-melting glass fine particles (which have an average particle diameter of 1) capable of achieving fire through are added so as to have a composition ratio as shown in Table 1. After the kneading was carried out by a high-speed stirring apparatus, the aluminum microparticles were treated with a three-roll mill while not being flattened to prepare a conductive fine particle-dispersed paste.

(Example 7)

A solution obtained by dissolving ethyl cellulose STD4 in rosin alcohol and a rosin alcohol solution of (meth)acrylic resin (Poly (BMA/MMA/HEMA)) obtained in Polymerization Example 4 were used and changed to Table 1. An inorganic fine particle-dispersed paste was produced in the same manner as in Example 1 except for the composition ratio described above.

(Example 8)

A rosin alcohol solution (Poly(CHMA/MMA/HEMA)) obtained in the polymerization example 5, a rosin compound (KR85, manufactured by Arakawa Chemical Co., Ltd.), and a PDP (Plasma display panel) as inorganic fine particles were used. In the slurry display panel, an inorganic fine particle dispersion paste was produced in the same manner as in Example 1 except that the composition ratio shown in Table 1 was changed to a green phosphor (Zn ₂ SiO ₄ : Mn, manufactured by Nichia Chemical Co., Ltd.). .

(Example 9)

The (meth)acrylic resin (Poly(CHMA/MMA/HEMA)) obtained in the polymerization example 6 was used in a Texanol solution, ethyl cellulose (STD7), and silver powder as inorganic fine particles (particle size was 2 μm, Zhaorong). An inorganic fine particle-dispersed paste was produced in the same manner as in Example 1 except that the composition ratio described in Table 1 was changed.

(Comparative Example 1)

An inorganic fine particle-dispersed paste was produced in the same manner as in Example 1 except that 1,6-hexanediol was used as the organic compound, and the composition ratio shown in Table 1 was changed.

(Comparative Example 2)

An inorganic fine particle-dispersed paste was produced in the same manner as in Example 3 except that 1,6-hexanediol was used as the organic compound, and the composition ratio shown in Table 1 was changed.

(Comparative Example 3)

An inorganic fine particle-dispersed paste was produced in the same manner as in Example 6 except that 2,2-dimethyl-1,3-propanediol was used as the organic compound, and the composition ratio shown in Table 1 was changed.

(Comparative Example 4)

An inorganic substance was produced in the same manner as in Example 6 except that 2,2-dimethyl-1,3-propanediol was used as the organic compound, and a pentaerythritol having a hydroxyl group at a normal temperature and having a boiling point of 300 ° C or higher was used. The microparticles disperse the paste.

(Comparative Example 5)

In the same manner as in Example 6, except that 2,2-dimethyl-1,3-propanediol as an organic compound was used, and 2-methyl-1,3-propanediol having a hydroxyl group and being a liquid at normal temperature was used. An inorganic fine particle dispersion paste was prepared.

(Comparative Example 6)

In the same manner as in Example 8, except that 2,2-dimethyl-1,3-propanediol as an organic compound was used, and 2-methyl-1,3-propanediol having a hydroxyl group and being a liquid at normal temperature was used. An inorganic fine particle dispersion paste was prepared.

(Comparative Example 7)

In the same manner as in Example 9, except that 2,2-dimethyl-1,3-propanediol as an organic compound was used, and 2-methyl-1,3-propanediol having a hydroxyl group and being liquid at normal temperature was used. An inorganic fine particle dispersion paste was prepared.

<Evaluation>

The inorganic fine particle-dispersed paste obtained in the examples and the comparative examples was subjected to the following evaluation. The results are shown in Table 2.

(1) Sinterability

The inorganic fine particle dispersion paste was applied onto a glass substrate using an applicator set at 5 mils, dried in a blowing oven at 150 ° C for 30 minutes, and then calcined in an electric furnace at 500 ° C for 30 minutes. The obtained sintered layer was measured for residual carbon (ppm) by a carbon-sulfur analyzer (manufactured by Horiba, Ltd.), and the calcined color was visually confirmed. The sinterability was evaluated as "○" when the residual carbon was 150 ppm or less, and the sinterability was evaluated as "x" when the residual carbon exceeded 150 ppm.

(2) Surface smoothness

The inorganic fine particle dispersion paste was applied onto a glass substrate using an applicator set to 5 mils, and dried in a blowing oven at 150 ° C for 30 minutes. The obtained inorganic fine particle-dispersed paste coating layer was measured for the center line average roughness (Ra) of the surface according to JIS B 0601, and when Ra was 1.0 μm or less, the surface smoothness was evaluated as "○", and when it exceeded 1.0 μm The surface smoothness was evaluated as "x". A stylus type roughness meter (manufactured by Tokyo Precision Co., Ltd., Surfcom 1400D) was used for the measurement.

Further, the viscosity of the inorganic fine particle-dispersed paste obtained in Comparative Example 2 was high, and the coating layer obtained by applying the inorganic fine particle-dispersed paste showed a fluctuation in film thickness.

(3) does not collapse dryness

A stripe screen printing plate having an emulsion thickness of 20 μm, a stainless steel mesh #300, an opening of the emulsion having a line width of 100 μm and a spacing of 300 μm was obtained in Examples 8, 9 and Comparative Examples 6 and 7. The inorganic fine particle dispersion paste was printed on a glass substrate and dried in a forced air oven set at 120 ° C for 20 minutes. Then, the height of the printed shape was evaluated using a laser microscope.

When the height of the printed shape after drying was 10 μm or more, it was evaluated as “○”, and the case where the height of the printed shape was reduced to a height of less than 10 μm during the drying process was evaluated as “×”.

[Industrial availability]

According to the present invention, it is possible to provide an inorganic fine particle-dispersed paste capable of forming a sintered layer excellent in surface smoothness.

Claims (7)

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, characterized in that The organic compound has one or more hydroxyl groups and is solid at normal temperature, and has a boiling point of less than 300 ° C, and is selected from the group consisting of 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and meat. Stigmasterol, cetyl alcohol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol At least one of the group consisting of trimethylolpropane and pentaerythritol, and the content of the organic compound is 1 to 30% by weight. The inorganic fine particle-dispersed paste of the first aspect of the invention, 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. The inorganic fine particle-dispersed paste of claim 1, wherein the (meth)acrylic resin has a fragment derived from a monomer having a polar group. A glass dielectric body produced by using the inorganic fine particle dispersion paste of claim 1 or 2. A ceramic green sheet produced by using the inorganic fine particle-dispersed paste of claim 1 or 2. A solar cell unit produced by using the inorganic fine particle dispersion paste of claim 1 or 2. A flat panel display manufactured by using the inorganic fine particle dispersion paste of claim 1 or 2.