KR20120052374A - Inorganic microparticle dispersion paste - Google Patents

Abstract

An inorganic fine particle dispersion paste capable of forming a sintered layer having excellent surface smoothness is provided.
The present invention is an inorganic fine particle dispersion paste containing at least one selected from the group consisting of ethyl cellulose, (meth) acrylic resin and polyvinyl acetal resin, an organic compound, an inorganic fine particle, and an organic solvent. It is an inorganic fine particle dispersion paste which has one or more hydroxyl groups, and is a room temperature solid and whose boiling point is less than 300 degreeC.

Description

Inorganic fine particle dispersion paste {INORGANIC MICROPARTICLE DISPERSION PASTE}

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

In recent years, the inorganic fine particle dispersion paste which disperse | distributed inorganic fine particles, such as electroconductive powder and ceramic powder, to binder resin is used in order to obtain the sintered compact of various shapes. In particular, phosphor pastes in which phosphors are dispersed in binder resins as inorganic fine particles, and glass pastes in which low melting glass is dispersed are used in plasma display panels and the like, and demand is increasing in recent years.

Moreover, the ceramic paste which disperse | distributed barium titanate and alumina to binder resin as inorganic fine particles is shape | molded in the green sheet, and is used for laminated electronic components, for example, a laminated ceramic capacitor.

In addition, the back electrode of a solar cell panel is normally formed by apply | coating the paste which disperse | distributed aluminum powder by screen printing, etc., drying, and baking.

For example, the dielectric layer of a plasma display panel is formed by printing a glass paste on a glass substrate, drying the solvent in a ventilation oven circulated through the furnace, and then degreasing and firing in a high temperature oven. As a glass paste for forming a dielectric layer, for example, Patent Literature 1 contains, as a composition for a dielectric layer of a plasma display panel, at least a glass frit containing a glass component, a dispersant, a pyrolysis binder, and a solvent. The green sheet obtained by apply | coating the composition for dielectric layers which is a polycarboxylic acid type high molecular compound, and the composition for dielectric layers on a support body, and then drying is disclosed.

Patent Literature 1 describes that in the composition for dielectric layers described in the document, the dispersion state of the glass flit is effectively improved.

The improvement of the dispersibility of such inorganic fine particles is important in order to form a uniform sintered layer and not to cause variations in the properties of the sintered layer. However, since the sintered layer is first formed through the printing, drying, degreasing, and firing process of the inorganic fine particle dispersion paste, it is finally formed only by improving the uniformity in the paste state, that is, the dispersibility of the inorganic fine particle. It is difficult to ensure the uniformity of the sintered layer used sufficiently.

Moreover, similarly to the green sheet of patent document 1, forming a uniform sintered layer by processing an inorganic fine particle dispersion paste into sheet form beforehand, and using the obtained green sheet is considered, When using a green sheet, The problem is that the adhesiveness of the green sheet to is insufficient.

Japanese Unexamined Patent Publication No. 2004-002164

An object of the present invention is to provide an inorganic fine particle dispersion paste capable of forming a sintered layer having excellent surface smoothness.

The present invention is an inorganic fine particle dispersion paste containing at least one selected from the group consisting of ethyl cellulose, (meth) acrylic resin and polyvinyl acetal resin, an organic compound, an inorganic fine particle, and an organic solvent. It is an inorganic fine particle dispersion paste which has one or more hydroxyl groups, and is a room temperature solid and whose boiling point is less than 300 degreeC.

The present invention is described in detail below.

Usually, a high boiling point solvent is used for the inorganic fine particle dispersion paste for forming a sintering layer, in order to ensure printability. In addition, in order to dry a high boiling point solvent efficiently and to improve productivity, a blowing oven is used in the drying process after printing. The present inventors found that surface roughening occurred in the coating layer of the inorganic fine particle dispersion paste due to the blowing in the oven, and as a result, the surface smoothness of the sintered layer was lowered and the performance of the sintered layer was deteriorated.

MEANS TO SOLVE THE PROBLEM In addition to at least 1 sort (s) chosen from the group which consists of an ethyl cellulose, a (meth) acrylic resin, and a polyvinyl acetal resin, an inorganic fine particle, and an organic solvent, this inventor further has one or more hydroxyl groups, and is a room temperature solid 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 step after printing, and at the time of drying in an oven, surface roughness due to blowing air in the oven is suppressed, and It turned out that it can dry uniformly, without causing the skinning phenomenon resulting from entanglement of resin. Furthermore, the present inventors found out that the sintered layer formed using the inorganic fine particle dispersion paste was excellent in surface smoothness, and came to complete this invention.

The inorganic fine particle dispersion paste of this invention contains at least 1 sort (s) chosen from the group which consists of ethyl cellulose, (meth) acrylic resin, and polyvinyl acetal resin.

The said ethyl cellulose is not specifically limited, What is necessary is just to select grade suitably according to the printing method of the inorganic fine particle dispersion paste obtained, the thickness of the target sintering layer, etc. Especially, when screen-printing, since ethyl cellulose which has thixotropy is generally preferable, the ethyl cellulose of grades, such as STD45 and STD100, is 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 dispersion paste, and since the viscosity of the inorganic fine particle dispersion paste tends to be high, grade ethyl cellulose of low viscosity specifications such as STD4 and STD10 desirable.

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, and n-butyl (meth) Acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isoboroyl (meth) acrylate, n- The polymer which consists of at least 1 sort (s) chosen from the group which consists of a stearyl (meth) acrylate, a benzyl (meth) acrylate, and the (meth) acrylic monomer which has a polyoxyalkylene structure is preferable. 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 also has excellent low temperature degreasing properties. Moreover, since the inorganic fine particle dispersion paste of this invention contains the organic compound mentioned later, the polymer which has 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.

As a monomer which has the said polar group, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, methacrylic acid, glycidyl methacrylate, glycerol monomethacrylate, etc. are mentioned, for example.

When it has a 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.

When content of the segment derived from the monomer which has the said polar group exceeds 20 weight%, thermal decomposition property at low temperature may be inhibited, the soot which adheres to inorganic fine particles may increase, and residual carbon of a sintered compact may increase. More preferably, it is 10 weight part or less.

It is preferable that the said (meth) acrylic resin has a hydrophilic functional group in a molecule terminal. Although the said hydrophilic functional group is not specifically limited, It is preferable that they are a carbonyl group, an amino group, and amide groups.

Generally, when (meth) acrylic resin which introduce | transduced highly functional groups, such as a carbonyl group, an amino group, and an amide group, was used for the ester substituent of a (meth) acrylic-type monomer, in the baking process of an inorganic fine particle dispersion paste, the ( Depolymerization of the meth) acrylic resin is inhibited, the thermal decomposition end temperature is increased, and the thermal decomposition property is very deteriorated.

On the other hand, when the (meth) acrylic resin which has a carbonyl group, an amino group, an amide group, etc. at the terminal of a molecule | numerator is used, depolymerization of this (meth) acrylic resin is not inhibited and it hardly affects thermal decomposition end temperature. Moreover, since inorganic fine particles, such as glass powder, have high interaction with a carbonyl group, an amino group, an amide group, etc., when (meth) acrylic resin which has a carbonyl group, an amino group, an amide group, etc. in a molecule terminal is used, the (meth) One molecular terminal of the acrylic resin is adsorbed on the surface of the inorganic fine particles, the other is in a form extending to the organic solvent side, prevents reaggregation of the inorganic fine particles, and can improve dispersion stability.

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 500000. If the said weight average molecular weight is less than 5000, the inorganic fine particle dispersion paste obtained may not obtain sufficient viscosity, may worsen screen printability, and also the surface roughness by receiving air blowing in oven in the drying process after printing By increasing, the surface smoothness of a sintered layer may fall. When the said weight average molecular weight exceeds 500000, the adhesive force of the inorganic fine particle dispersion paste obtained may become high too much, soft yarn may generate | occur | produce, and screen printability may worsen. The upper limit with preferable weight average molecular weight is 100000, and a more preferable upper limit is 50000. In particular, when the weight average molecular weight by polystyrene conversion of the said (meth) acrylic resin is 10000-50000, since a clear image is obtained at the time of screen printing, it is preferable.

In addition, the weight average molecular weight by polystyrene conversion can be obtained by performing GPC measurement using the column LF-804 (made by Showa Denko) as a column, for example.

The method for producing the above-mentioned (meth) acrylic resin is not particularly limited, and for example, under the polymerization initiator having a carbonyl group, an amino group, an amide group or the like, the above-mentioned (meth) acrylic monomer may be used as a free radical polymerization method or a living radical polymerization method. , (Meth) acrylic monomers described above under the method of copolymerizing by conventionally known methods such as inipher polymerization, anion polymerization, living anion polymerization, or a chain transfer agent having a carbonyl group, an amino group, an amide group, or the like. The method of copolymerizing by conventionally well-known methods, such as a free radical polymerization method, a living radical polymerization method, an inipher polymerization method, an anion polymerization method, a living anion polymerization method, etc. are mentioned. 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 group or the like can be introduced at more molecular terminals. Moreover, it can confirm by ¹³ C-NMR that carbonyl group, an amino group, an amide group, etc. were introduce | transduced only in the molecular terminal of the said (meth) acrylic resin.

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

It is preferable that the saponification degree of the said polyvinyl alcohol is 80 mol% or more. If the degree of saponification is less than 80 mol%, the solubility of the polyvinyl alcohol in water becomes poor, so that the acetalization reaction is difficult. If the amount of hydroxyl groups is small, the acetalization reaction itself may be difficult.

It is preferable that the polymerization degree of the said polyvinyl alcohol is 1000-4000.

When the said degree of polymerization is less than 1000, for example, when used as a material of a ceramic green sheet, strength may become inadequate. When the said polymerization degree exceeds 4000, the solubility to water may fall, the viscosity of aqueous solution may become high too much, and acetalization may become difficult. Moreover, solution viscosity becomes too high and applicability | paintability falls.

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 synthesis | combination. In addition, when mixing 2 or more types of polyvinyl alcohols, the average of these polymerization degrees is used.

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

Examples of the vinyl esters include vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, and the like, and vinyl acetate is preferable from an economical point of view.

Moreover, it is preferable that the said polyvinyl alcohol contains the alpha-olefin in a principal chain.

Since the hydrogen bonding force of the polyvinyl acetal resin is weakened by the α-olefin, the stability over time of the viscosity can be improved, or the screen printability can be improved.

Examples of the α-olefins include methylene, ethylene, propylene, isopropylene, butylene, isobutylene, pentylene, hexylene, cyclohexylene, cyclohexylethylene, cyclohexyl propylene, and the like. Ethylene is preferred.

As content of the said alpha olefin, it is preferable that it is 1-20 mol%.

When content of the said alpha-olefin is less than 1 mol%, the characteristic of the polyvinyl acetal resin obtained will not differ at all from an unmodified polyvinyl acetal resin, and when it exceeds 20 mol%, the solubility of polyvinyl alcohol in water will be In order to reduce, the acetalization reaction may be difficult, or the hydrophobicity of the completed polyvinyl acetal resin may become too strong, solubility in an organic solvent may be lowered.

The said polyvinyl alcohol may copolymerize another ethylenically unsaturated monomer in the range which does not impair the effect of this invention.

As such an ethylenically unsaturated monomer, acrylic acid, methacrylic acid, (phthalic) phthalic acid, (maleic anhydride), itaconic acid (anhydride), acrylonitrile methacrylonitrile, acrylamide, methacrylamide, trimethyl, for example -(3-acrylamide-3-dimethylpropyl) -ammonium chloride, acrylamide-2-methylpropanesulfonic acid, and its sodium salt, ethyl vinyl ether, butyl vinyl ether, N-vinylpyrrolidone, vinyl chloride, vinyl bromide And vinyl fluoride, vinylidene chloride, vinylidene fluoride, tetrafluoroethylene, sodium vinyl sulfonate, sodium allyl sulfonate, and the like.

Moreover, terminal modified polyvinyl alcohol obtained by copolymerizing vinyl ester monomers, such as vinyl acetate, and ethylene in the presence of thiol compounds, such as thiol acetic acid and mercaptopropionic acid, and saponifying it can also be used.

The aldehyde used in the reaction is not particularly limited, but for example, formaldehyde (including paraformaldehyde), acetaldehyde (including paraacetaldehyde), propionaldehyde, butylaldehyde, amylaldehyde, hexyl aldehyde, heptyl Aldehyde, 2-ethylhexylaldehyde, cyclohexylaldehyde, furfural, glyoxal, glutaraldehyde, benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxyaldehyde, m-hydroxyaldehyde , Phenyl acetaldehyde, phenyl propionaldehyde and the like.

These aldehydes may be used alone or in combination of two or more, and acetaldehyde and / or butylaldehyde are preferably used.

The said polyvinyl acetal resin can be obtained by melt | dissolving a polyvinyl alcohol resin with hot water, adding an aldehyde so that it may become a predetermined acetalization degree in presence of an acid catalyst, making it react, and then washing with water, neutralizing, and drying.

The acid catalyst is not particularly defined, and both organic acids and inorganic acids can be used. Examples thereof include acetic acid, paratoluenesulfonic acid, nitric acid, sulfuric acid, hydrochloric acid, and the like.

Moreover, as alkali used for neutralization, sodium hydroxide, potassium hydroxide, ammonia, sodium acetate, sodium carbonate, sodium hydrogencarbonate, potassium carbonate, etc. are mentioned, for example.

It is preferable that the acetalization degree of the polyvinyl acetal resin used for this invention is 60-80 mol%. When the acetalization degree is less than 60 mol%, the hydrogen bonding property of polyvinyl acetal resin may become too strong, and sufficient screen printability may not be obtained.

On the other hand, polyvinyl acetal resins having an acetalization degree exceeding 80 mol% are generally difficult to manufacture industrially (according to PJ Flory's theoretical calculation, the maximum acetalization degree is preferably 81.6 mol%. J Am. Chem. Soc., 61, 1518 (1939).

Although the content of at least 1 sort (s) chosen from the group which consists of said ethyl cellulose, (meth) acrylic resin, and polyvinyl acetal resin in the inorganic fine particle dispersion paste of this invention is not specifically limited, A preferable minimum is 5 weight%, and a preferable upper limit is preferable. Is 25% by weight. If content of at least 1 sort (s) chosen from the group which consists of the said ethyl cellulose, (meth) acrylic resin, and polyvinyl acetal resin is less than 5 weight%, the inorganic fine particle dispersion paste obtained will not obtain sufficient viscosity, and screen-printability It may worsen, and also the surface roughness by receiving air blowing in oven in the drying process after printing may fall, and the surface smoothness of a sintering layer may fall. When the said content exceeds 25 weight%, the inorganic fine particle dispersion paste obtained may become high in viscosity and adhesive force too much, and screen printability may worsen.

The inorganic fine particle dispersion paste of this invention has one or more hydroxyl groups, and contains the organic compound whose normal temperature is solid and whose boiling point is less than 300 degreeC.

The organic compound is a solid at room temperature. By the said organic compound being solid at normal temperature, the obtained inorganic fine particle dispersion paste is suppressed the surface roughness by blowing air in oven in the drying process after printing, and a sintered layer is excellent in surface smoothness.

Moreover, although the said organic compound is solid at normal temperature, it can melt | dissolve in the organic solvent mentioned later, and paste-like inorganic fine particle dispersion paste can be obtained.

In addition, the said organic compound is different from the organic solvent mentioned later.

The mechanism by which drying property improves by adding the organic compound which has one or more said hydroxyl groups, and is a room temperature solid and whose boiling point is less than 300 degreeC is considered as follows.

The surface of the inorganic fine particles added to the inorganic fine particle dispersion paste is in a very high polar state and has a function of sucking high functional groups. Usually, when the organic material which has a high polar functional group is not added to an inorganic fine particle dispersion paste, microparticles aggregate in a solvent and generate precipitation.

Thus, by adding an organic compound having at least one hydroxyl group and a solid at room temperature and having a boiling point of less than 300 ° C, the inorganic fine particle dispersion paste becomes liquid by mixing with an organic solvent, so that it is first adsorbed to the surface of the inorganic fine particles. In addition, under drying conditions, the layer which can be evaporated can be formed around inorganic fine particles.

On the other hand, 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, and therefore, under drying conditions, the organic solvent is dried from the surface of the inorganic fine particle dispersion paste. The surface causes skinning, and a thin resin layer is formed.

The surface resin layer formed by such drying is very nonuniform and depends on drying conditions, and forms a more nonuniform layer under strong drying conditions under blowing conditions. Therefore, the organic solvent which exists under the skinned resin layer becomes difficult to evaporate, and the unevenness | corrugation easily arises on the coating film surface.

On the other hand, the said organic compound which formed the layer on the surface of an inorganic fine particle is evaporated under dry conditions, and forms the window which evaporates the internal organic solvent. Therefore, the drying nonuniformity of the organic solvent resulting from skinning of resin can be reduced, and even if drying is inadequate, since it is a room temperature solid, it is hard to act as a plasticizer and it becomes easy to maintain smoothness.

The said organic compound has a boiling point below 300 degreeC. If the boiling point of the said organic compound is 300 degreeC or more, the obtained inorganic fine particle dispersion paste will fall in the drying property in the drying process after printing, and the surface smoothness of a sintering layer will fall. It is preferable that boiling point is less than 280 degreeC, and, as for the said organic compound, it is more preferable that it is less than 260 degreeC.

Moreover, although the minimum of the boiling point of the said organic compound is not specifically limited, It is preferable that boiling point is 160 degreeC or more. If the boiling point of the said organic compound is less than 160 degreeC, the inorganic fine particle dispersion paste obtained will be easy to dry during printing, and when using for long time continuous printing, a problem may arise. In addition, the said boiling point means the boiling point in normal pressure.

The said organic compound has one or more hydroxyl groups. By having one or more of said hydroxyl groups, the storage stability of the inorganic fine particle dispersion paste obtained can be improved, and also the viscosity of an inorganic fine particle dispersion paste can be raised by interaction with a hydroxyl group, resin, and an organic solvent, and screen It can be set as a viscosity suitable for printing.

The organic compound is not particularly limited as long as it has at least one hydroxyl group and is a room temperature solid and has a boiling point of less than 300 ° C., but an alcohol-based organic compound composed of fatty chains having 5 to 20 carbon atoms is preferable.

The alcohol-based organic compound is not particularly limited, and for example, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, myristyl alcohol, cetyl alcohol, 2,2-dimethyl-1, 3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, trimethylolpropane, pentaerythritol, etc. are mentioned.

Among them, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol and 2-butyl-2-ethyl-1,3 having a high ratio of hydroxyl groups to carbon atoms Since 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 dispersion paste used for screen printing.

Although content of the said organic compound in the inorganic fine particle dispersion paste of this invention is not specifically limited, A preferable minimum is 1 weight%, and a preferable upper limit is 30 weight%. If the content of the organic compound is less than 1% by weight, the resulting inorganic fine particle dispersion paste may have a reduced dryness in the drying step after printing, an increase in surface roughness due to blowing in the oven, or skinning resulting from entanglement of the resin. By surface development, the surface smoothness of a sintered layer may fall. When content of the said organic compound exceeds 30 weight%, the inorganic fine particle dispersion paste obtained may worsen storage stability.

The inorganic fine particle dispersion paste of this invention contains the organic solvent.

The said organic solvent is not specifically 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, butylcarbitol, butylcarbitol acetate, texanol, isophorone, butyl lactate, dioctylphthalate, dioctyl adipate, benzyl alcohol, phenyl propylene glycol, cresol, terpineol, Terpineol 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 independently and may use 2 or more types together.

Although content of the said organic solvent in the inorganic fine particle dispersion paste of this invention is not specifically limited, A preferable minimum is 10 weight%, and a preferable upper limit is 60 weight%. When content of the said organic solvent is less than 10 weight%, the viscosity and adhesive force of the inorganic fine particle dispersion paste obtained may become high too much, and screen printability may worsen. When content of the said organic solvent exceeds 60 weight%, the inorganic fine particle dispersion paste obtained may not acquire sufficient viscosity, the screen printability may worsen, and also dryness may fall in the drying process after printing, or oven The surface roughness of a sintered layer may fall by the surface roughness by receiving air blowing inside.

Moreover, 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 an organic compound. When the organic solvent or the organic compound is insufficiently dried and calcined in a state in which the organic solvent or the organic compound remains inside, the soot generated by thermal decomposition of the binder resin is likely to be adsorbed on the surface of the fine particles. In comparison with the case, the carbon residue tends to increase.

The inorganic fine particle dispersion paste of this invention contains an inorganic fine particle.

The said inorganic fine particle is not specifically limited, For example, metal microparticles | fine-particles, metal oxide microparticles | fine-particles, etc., such as glass powder, ceramic powder, fluorescent substance microparticles | fine-particles, a silicon oxide, etc. are mentioned.

The glass powder is not particularly limited, and examples thereof include bismuth oxide glass, silicate glass, lead glass, zinc glass, boron or glass powder such as _{glass, CaO-Al 2 O 3 -SiO} 2 series, MgO-Al ₂ O ₃ -SiO ₂ system, LiO ₂ -Al and there are exemplified glass powder and the like of various silicon oxides such as ₂ O ₃ -SiO ₂ system.

Further, as the 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-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, BaO-ZnO Glass powders such as -B ₂ O ₃ -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 powders of PbO-B ₂ O ₃ -SiO ₂ mixtures, lead-free BaO-ZnO-B ₂ O ₃ -SiO ₂ mixtures or ZnO-Bi ₂ O ₃ -B ₂ O ₃ -SiO ₂ mixtures Pb free glass powders, such as these, are preferable.

The ceramic powder is not particularly limited, and examples thereof include alumina, zirconia, titanium oxide, barium titanate, alumina nitride, silicon nitride, and boron nitride.

Further, nano ITO used for the transparent electrode material, nano titanium oxide used for the dye-sensitized solar cell, and the like can also be preferably used.

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 said metal fine particle is not specifically limited, For example, the powder etc. which consist of nickel, palladium, platinum, gold, silver, aluminum, tungsten, these alloys, etc. are mentioned.

Moreover, metals, such as copper and iron, whose adsorption characteristics with a carboxyl group, an amino group, and an amide group are favorable, and are easy to oxidize, can also be used preferably. These metal powders may be used independently and may use 2 or more types together.

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 dispersion paste may not obtain sufficient viscosity, may have poor screen printability, and may be caused by blowing air in an oven in a drying step after printing. As surface roughness increases, the surface smoothness of a sintered layer may fall. When content of the said inorganic fine particle exceeds 90 weight%, the inorganic fine particle dispersion paste obtained may have a high viscosity, and screen printability may worsen.

It is preferable that the inorganic fine particle dispersion paste of this invention contains surfactant in order to stabilize the compatibility of the said organic compound and another material. Although the said surfactant is not specifically limited, 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 thermal decomposition property of the said nonionic surfactant is favorable, when content exceeds 5 weight%, the thermal decomposition property of an inorganic fine particle dispersion paste may fall.

The method of manufacturing the inorganic fine particle dispersion paste of this invention is not specifically limited, A conventionally well-known stirring method is mentioned, Specifically, it consists of the said ethyl cellulose, (meth) acrylic resin, and polyvinyl acetal resin, for example. The method of stirring at least 1 sort (s) chosen from the group, the said organic compound, the said organic solvent, the said inorganic fine particle, and other components added as needed with three rolls etc. are mentioned.

Since the inorganic fine particle dispersion paste of this invention dries satisfactorily in the drying process after printing, surface roughness by blowing air in an oven can be suppressed, and the bad influence of the skinning phenomenon at the time of drying can be prevented, A sintered layer excellent in smoothness can be formed. Therefore, for example, 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 or conductive powder such as aluminum is used as inorganic fine particles. It is preferably used.

Especially, the glass paste at the time of using glass powder as an inorganic fine particle is used preferably in order to form the dielectric layer etc. of a plasma display panel. Glass dielectrics produced using such glass pastes are also one of the present inventions.

In addition, the inorganic fine particle dispersion paste of the present invention is characterized in that it can be dried quickly while preventing skinning phenomenon during drying. Therefore, when a conventional resin paste is used, it can be used suitably also for the member which was difficult to maintain a shape by flowing at the time of drying. Moreover, the state which cannot maintain a shape in this way is also called "flow."

For example, when the conventional resin paste was used for the phosphor in the cell of the back plate of the plasma display, the surface electrode of the solar cell, or the like, it was not possible to flow during drying and maintain the height after printing. By using a paste, it becomes possible to remove an organic solvent before flowing and flowing low during drying, and it can use it also suitably as a material of a flat panel display.

Flat panel displays produced using the inorganic fine particle dispersion paste of the present invention are also one of the present invention.

According to this invention, the inorganic fine particle dispersion paste which can form the sintered layer excellent in surface smoothness can be provided.

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

(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 separable flask equipped with a stirrer, a cooler, a thermometer, an oil bath, and a nitrogen gas inlet to obtain a monomer mixture. .

After removing the dissolved oxygen by bubbling the obtained monomer liquid mixture for 20 minutes using nitrogen gas, it heated up until the oil bath reached 130 degreeC, stirring and replacing the inside of a separable flask system with nitrogen gas. A solution in which 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide] was dispersed with texanol was added as a polymerization initiator. Moreover, the texanol solution containing a polymerization initiator was added several times during superposition | polymerization, and 1.5 weight part of polymerization initiators were added with respect to 100 weight part of monomers in total.

After 7 hours from the start of the polymerization, the reaction solution was cooled to room temperature to terminate the polymerization. This obtained the texanol solution of (meth) acrylic resin (Poly (IBMA)) 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) as the column. As a result, the weight average molecular weight in terms of 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, a cooler, a thermometer, an oil bath and a nitrogen gas inlet; 100 weight part of acidols were mixed and the monomer liquid mixture was obtained.

After removing the dissolved oxygen by bubbling the obtained monomer liquid mixture for 20 minutes using nitrogen gas, it heated up until the oil bath reached 130 degreeC, stirring and replacing the inside of a separable flask system with nitrogen gas. A solution in which 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide] was dispersed with texanol was added as a polymerization initiator. Moreover, the texanol solution containing a polymerization initiator was added several times during superposition | polymerization, and 1.5 weight part of polymerization initiators were added with respect to 100 weight part of monomers in total.

After 7 hours from the start of the polymerization, the reaction solution was cooled to room temperature to terminate the polymerization. This obtained the texanol solution of (meth) acrylic resin (Poly (BMA / MMA)) 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) as the column. As a result, the weight average molecular weight in terms of polystyrene was 40,000.

(Polymerization example 3)

100 parts by weight of a mixture of butyl methacrylate and hydroxyethyl methacrylate (BMA / HEMA = 9/1) in a 2 l separable flask equipped with a stirrer, a cooler, a thermometer, an oil bath and a nitrogen gas inlet. 100 weight part of terpineol was mixed as a solvent, and the monomer liquid mixture was obtained.

After removing the dissolved oxygen by bubbling the obtained monomer liquid mixture for 20 minutes using nitrogen gas, it heated up until the oil bath reached 130 degreeC, stirring and replacing the inside of a separable flask system with nitrogen gas. As a polymerization initiator, a solution in which azobisisobutyronitrile was dispersed in terpineol was added. Moreover, the terpineol solution containing a polymerization initiator was added several times during superposition | polymerization, and 0.8 weight part of polymerization initiators were added with respect to 100 weight part of monomers in total.

After 7 hours from the start of the polymerization, the reaction solution was cooled to room temperature to terminate 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) as the column. As a result, the weight average molecular weight in terms of polystyrene was 140,000.

(Polymerization example 4)

In a 2 L separable flask with a stirrer, cooler, thermometer, oil bath and nitrogen gas inlet, a mixture of butyl methacrylate, methyl methacrylate and hydroxyethyl methacrylate (BMA / MMA / HEMA = 4 / 4/2) 100 weight part and 100 weight part of terpineols were mixed as an organic solvent, and the monomer liquid mixture was obtained.

After removing the dissolved oxygen by bubbling the obtained monomer liquid mixture for 20 minutes using nitrogen gas, it heated up until the oil bath reached 130 degreeC, stirring and replacing the inside of a separable flask system with nitrogen gas. As a polymerization initiator, a solution in which azobisisobutyronitrile was dispersed in terpineol was added. In addition, the terpineol solution containing a polymerization initiator was added several times during superposition | polymerization, and 1.5 weight part of polymerization initiators were added with respect to 100 weight part of monomers in total.

After 7 hours from the start of the polymerization, the reaction solution was cooled to room temperature to terminate 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) as the column. As a result, the weight average molecular weight in terms of polystyrene was 50,000.

(Polymerization example 5)

To a 2 l separable 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 weight part, 0.2 weight part of mercaptopropanediol as a chain transfer agent, and 100 weight part of terpineol as an organic solvent were mixed, and the monomer liquid mixture was obtained.

After removing the dissolved oxygen by bubbling for 20 minutes using nitrogen gas, the obtained monomer liquid mixture was heated up until the water bath boiled, replacing and stirring inside the separable flask system with nitrogen gas. 0.1 weight part of organic oxide polymerization catalysts (Paroyl 355, Nichiyu Corporation) were added as a polymerization initiator, the polymerization initiator was added several times during superposition | polymerization, and a total of 1.5 weight part of polymerization initiators was added with respect to 100 weight part of monomers in total.

After 7 hours from the start of the polymerization, the reaction solution was cooled to room temperature to terminate the polymerization. This obtained the terpineol solution of the (meth) acrylic resin (Poly (CHMA / MMA / HEMA)) which has a hydroxyl group at the terminal of a molecule | numerator. The obtained polymer was analyzed by gel permeation chromatography using column LF-804 (manufactured by Showa Denko) as the column. As a result, the weight average molecular weight in terms of polystyrene was 50,000.

(Polymerization example 6)

Instead of terpineol in polymerization example 5, texanol was used, and the texanol solution of (meth) acrylic resin (Poly (CHMA / MMA / HEMA)) having a hydroxyl group at the terminal of the molecule was used in the same manner as in polymerization example 5. Got it. The obtained polymer was analyzed by gel permeation chromatography using column LF-804 (manufactured by Showa Denko) as the column. As a result, the weight average molecular weight in terms of polystyrene was 80,000.

(Example 1)

Ethyl cellulose STD4 was dissolved in terpineol. About this terpineol solution, 1, 6- hexanediol was added as an organic compound so that it might become the composition ratio shown in Table 1, and the vehicle composition was obtained.

The obtained vehicle composition, a non-ionic surfactant a BL-4.2 (Nikko Chemical Co., Ltd.), the glass particles (SiO ₂ of the inorganic fine particles having an average particle diameter of 2.0 ㎛ 32.5%, 20.5% of B ₂ O _3, ZnO 18%, Al ₂ O ₃ 10%, BaO 3.5%, Li ₂ O 9%, Na ₂ O 6%, SnO ₂ 0.5%) was added to the composition ratio shown in Table 1, and then It knead | mixed enough using the stirring apparatus, it processed until it became smooth with three roll mills, and produced the inorganic fine particle dispersion paste.

(Example 2)

Inorganic fine particles were prepared 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 shown in Table 1 was changed. Dispersion pastes were prepared.

(Example 3)

A texanol solution of (meth) acrylic resin (Poly (IBMA)) obtained in Polymerization Example 1 was used in place of the terpineol solution of ethyl cellulose STD4, except that the composition ratio shown in Table 1 was changed to the same as that in Example 1. Inorganic fine particle dispersion paste was prepared.

(Example 4)

Example 1 except having changed into the composition ratio shown in Table 1 using the texanol solution of the (meth) acrylic resin (Poly (BMA / MMA)) obtained by the polymerization example 2 instead of the terpineol solution of ethyl cellulose STD4. An inorganic fine particle dispersion paste was prepared in the same manner as in the following.

(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 stirred at a temperature of 90 ° C for about 2 hours to dissolve.

The solution was cooled to 40 ° C., 20 g of hydrochloric acid having a concentration of 35% by weight and 145 g of n-butylaldehyde were added thereto, and the acetalization reaction was carried out by lowering the liquid temperature to 15 ° C. and maintaining this temperature. Precipitated.

Then, liquid temperature was hold | maintained at 40 degreeC for 3 hours, reaction was completed, and it neutralized, washed with water, and dried by a conventional method, and obtained the white powder of polyvinyl acetal resin.

The obtained polyvinyl acetal resin was dissolved in DMSO-d ₆ (dimethyl sulfoxide), and the acetalization degree was measured using ¹³ C-NMR (nuclear magnetic resonance spectrum), and the acetalization degree was 78 mol%.

5 weight part of obtained polyvinyl butyral resin is added to the mixed solvent of 22 weight part of toluene, and 11 weight part of ethanol, and it melt | dissolves, and also 2 weight part of dibutyl phthalates as a plasticizer, and 2, 2- dimethyl- as an organic compound 1,3-propanediol was added so that it might become the composition ratio shown in Table 1, and it stirred and melt | dissolved. To the obtained resin solution, 50 parts by weight of barium titanate (“BT-01 (average particle diameter 0.3 μm)” manufactured by Sakai Chemical Co., Ltd.) was added as a ceramic powder, and mixed with a ball mill for 48 hours to prepare an inorganic fine particle dispersion paste composition.

(Example 6)

To the terpineol solution of the (meth) acrylic resin (Poly (BMA / HEMA)) obtained in the polymerization example 3, terpineol was added and dissolved so that it might become the composition ratio shown in Table 1. 2,2-dimethyl-1,3-propanediol was further added here as an organic compound so that it might become the composition ratio shown in Table 1, and it disperse | distributed with the high speed disperser.

As the conductive fine particles, aluminum fine particles (average particle diameter of 5 mu m) and low melting point glass fine particles (average particle diameter of 1 mu m) enabling fire through were added so as to have a composition ratio shown in Table 1, using a high-speed stirring device. After sufficiently kneading, the treatment was carried out with three roll mills while paying attention not to crush the aluminum fine particles flat, to prepare a conductive fine particle dispersion paste.

(Example 7)

Using a solution in which ethyl cellulose STD4 was dissolved in terpineol and a terpineol solution of (meth) acrylic resin (Poly (BMA / MMA / HEMA)) obtained in Polymerization Example 4, the composition ratios shown in Table 1 were used. Except having changed, it carried out similarly to Example 1, and prepared the inorganic fine particle dispersion paste.

(Example 8)

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

(Example 9)

Texanol solution of (meth) acrylic resin (Poly (CHMA / MMA / HEMA)) obtained in Polymerization Example 6, ethyl cellulose (STD7), and silver powder (particle diameter of 2 m, manufactured by Shoei Chemical Co., Ltd.) were used as inorganic fine particles. Inorganic fine particle dispersion paste was produced like Example 1 except having changed so that it might become the composition ratio shown in Table 1.

(Comparative Example 1)

An inorganic fine particle dispersion paste was produced in the same manner as in Example 1, except that 1,6-hexanediol as the organic compound was not used and the composition ratio shown in Table 1 was changed.

(Comparative Example 2)

An inorganic fine particle dispersion paste was produced in the same manner as in Example 3 except that the composition ratio shown in Table 1 was not used without using 1,6-hexanediol as the organic compound.

(Comparative Example 3)

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

(Comparative Example 4)

An inorganic fine particle dispersion paste was prepared in the same manner as in Example 5 except that instead of 2,2-dimethyl-1,3-propanediol, which is an organic compound, having a hydroxyl group and a pentaerythritol having a boiling point of 300 ° C or higher, Prepared.

(Comparative Example 5)

An inorganic fine particle dispersion paste was prepared in the same manner as in Example 6, except that 2-methyl-1,3-propanediol having a hydroxyl group was used instead of the organic compound 2,2-dimethyl-1,3-propanediol. Was prepared.

(Comparative Example 6)

Inorganic fine particle dispersion paste similarly to Example 8 except having 2, 2- dimethyl- 1, 3- propanediol which is an organic compound, and having a hydroxyl group and using 2-methyl- 1, 3- propanediol which is a normal temperature liquid. Was prepared.

(Comparative Example 7)

Inorganic fine particle dispersion paste similarly to Example 9 except having 2, 2- dimethyl- 1, 3- propanediol which is an organic compound, and having a hydroxyl group and using 2-methyl- 1, 3- propanediol which is a normal temperature liquid. Was prepared.

<Evaluation>

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

(1) sinterability

The inorganic fine particle dispersion paste was apply | coated on the glass substrate using the applicator set to 5 mils, and it dried for 30 minutes in 150 degreeC ventilation oven, and baked for 30 minutes in the 500 degreeC electric furnace. Regarding the obtained sintered layer, residual carbon (ppm) was measured with the carbon sulfur analyzer (manufactured by Horiba, Ltd.), and it was confirmed by browning visually. The case where residual carbon was 150 ppm or less was evaluated as "(circle)", and the case where residual carbon exceeded 150 ppm was made into "x" and sinterability was evaluated.

(2) surface smoothness

The inorganic fine particle dispersion paste was apply | coated on the glass substrate using the applicator set to 5 mils, and it dried for 30 minutes in 150 degreeC ventilation oven. About the obtained inorganic fine particle dispersion paste coating layer, the center line average roughness Ra of the surface is measured by the method based on JIS B0601, and the case where Ra is 1.0 micrometer or less is "(circle)" and the case where it exceeds 1.0 micrometer is "x". Surface smoothness was evaluated. A tactile roughness meter (Sapcom 1400D, manufactured by Tokyo Precision Co., Ltd.) was used for the measurement.

Moreover, the inorganic fine particle dispersion paste obtained by the comparative example 2 was high in viscosity, and the coating layer obtained by apply | coating this inorganic fine particle dispersion paste showed the variation in the film thickness.

(3) non-flow dryness

Inorganic fine particle dispersion obtained in Examples 8 and 9 and Comparative Examples 6 and 7 using a slit screen printing plate having an oil thickness of 20 µm, a stainless steel mesh # 300, a line width of the opening of the emulsion, and a width of 100 µm and a space of 300 µm. The paste was printed on a glass substrate and dried for 20 minutes in a blower oven set at 120 ° C.

And the height of the printing shape was evaluated using the laser microscope.

The case where the height of the print shape after drying was 10 micrometers or more was made into "(circle)", and the case where the height of the print shape became the height less than 10 micrometers during drying was made into "x".

Industrial availability

According to this invention, the inorganic fine particle dispersion paste which can form the sintered layer excellent in surface smoothness can be provided.

Claims (6)

As an inorganic fine particle dispersion paste containing at least 1 sort (s) chosen from the group which consists of ethyl cellulose, a (meth) acrylic resin, and a polyvinyl acetal resin, an organic compound, an inorganic fine particle, and an organic solvent,
The said organic compound has one or more hydroxyl groups, In addition, Inorganic fine particle dispersion paste which is a normal temperature solid, and whose boiling point is less than 300 degreeC. The method of claim 1,
The inorganic fine particle dispersion paste is at least one selected from the group consisting of lead-free glass fine particles, ceramic fine particles and aluminum fine particles. It is manufactured using the inorganic fine particle dispersion paste of Claim 1 or 2, The glass dielectric material characterized by the above-mentioned. It is manufactured using the inorganic fine particle dispersion paste of Claim 1 or 2, The ceramic green sheet characterized by the above-mentioned. It is manufactured using the inorganic fine particle dispersion paste of Claim 1 or 2, The solar cell characterized by the above-mentioned. It is manufactured using the inorganic fine particle dispersion paste of Claim 1 or 2, The flat panel display characterized by the above-mentioned.