JP2002020570A - Acrylic binder resin composition for baking type paste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a binder for a baking type paste having excellent baking properties, viscosity characteristics and excellent workability in various processing methods without causing stringing phenomena. SOLUTION: This acrylic binder resin composition for a baking type paste is characterized by comprising (A) 100 mass parts of a thermoplastic acrylic (co)polymer having 40,000-100,000 weight-average molecular weight, (B) 0.5-10 mass parts of a thixotropic agent and (C) 100-400 mass parts of an organic solvent having >=150 deg.C boiling point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to Ag, Cu, N
The present invention relates to a resin composition for a binder for a paste for shaping and sintering various fillers including conductor powders such as i and Pd on a base material such as a ceramic substrate and a capacitor, and more particularly, for use in screen printing. The present invention relates to a binder resin composition for a firing type paste which is excellent in stringing resistance and firing properties when used in a printing method of a fine pattern and dip coating.

[0002]

2. Description of the Related Art Conventionally, metals and inorganic fillers (hereinafter, referred to as "metal" or "inorganic filler") have been used.
A method of manufacturing an electronic material such as a conductor or a ceramic molded body by dispersing a binder or a filler) into a binder, producing a pattern or a molded body, and then thermally decomposing the binder component by firing. I have. The binder used in this method is necessary for maintaining workability during molding and for securing the filler so that the molded body is not damaged when moving, and before the molded body is made into a final product. It is removed in the pyrolysis step of sintering the filler. Therefore, as the performance required for the binder, it is necessary to have good thermal decomposability and excellent workability in each processing.

As each processing method, there are a method of forming a slurry in which a slurry in which a filler is dispersed by screen printing or a doctor plate or the like, and a processing method by dip coating. In particular, when the above-mentioned binder is used in screen printing or dip coating, it is necessary to reduce the amount of the binder component contained as much as possible in order to increase the filling rate of the filler component to be sintered. Therefore, it is necessary that the binder component has a low solid content as much as possible and has a viscous property capable of exhibiting a sufficiently high viscosity for use in screen printing and dip coating. For this reason, conventionally,
As the binder, a solvent-based binder resin in which butyral resin, ethyl cellulose, or the like is dissolved in an organic solvent has been used.

On the other hand, for components used in recent electronic materials, fillers that can be fired at a low temperature, such as glass powder, from high-temperature firing type fillers such as alumina have been used. It is becoming something of. However, the binder of the butyral resin and the ethyl cellulose resin cannot cope with such a wide range of firing conditions, particularly when sintering a low-temperature firing type filler or in a reducing atmosphere to prevent oxidation of the metal filler. In the case of sintering the filler by the above method, there is a problem that sludge is generated as a firing defect, and characteristics of a product such as a finished ceramic or metal conductor are deteriorated.

[0005]

In order to solve the problem of sludge generation due to such poor firing of the binder, an acrylic resin binder using an acrylic resin having good firing properties has been proposed. For example, a copolymer of isobutyl methacrylate with 2-ethylhexyl methacrylate and a methacrylate having a hydroxyl group at the β-position or the α-position (Japanese Patent Laid-Open No. 10-167736).
Is mentioned. However, in the above-mentioned acrylic resin binder, since the acrylic resin is a main component, the thermal decomposition property is improved, but the viscosity property is low, and in order to develop the high viscosity required when used for screen printing or the like. It was necessary to increase the molecular weight of the acrylic copolymer. For this reason, the conventional acrylic resin binder causes a stringing phenomenon due to a high molecular weight, and cannot satisfy the workability required as a binder such as printability or dip coating suitability.

The present invention has been made in view of the above circumstances, and provides a binder for a sinterable paste having excellent workability and viscous properties and good workability in various processing methods that do not cause a stringing phenomenon. The purpose is to:

[0007]

Means for Solving the Problems In order to solve the above problems, the present inventors have conducted intensive studies. As a result, a resin composition containing a low molecular weight acrylic resin composition and a thixotropic agent has been found to have a low content. It has good workability in various processing methods because it can express high viscosity characteristics with solid content and does not cause stringing phenomenon,
In addition, they have found that they have good calcination properties and have thermal decomposability that does not leave sludge, and have completed the present invention by using them as binders for calcination type pastes.

That is, the present invention relates to (A) an acrylic (co) weight based on 100 parts by mass of a thermoplastic acrylic (co) polymer having a weight average molecular weight of 40,000 to 100,000. (B) 0.5 to 10 parts by mass of a thixotropic agent, and (C) 100 to 400 parts by mass of an organic solvent having a boiling point of 150 ° C. or more (hereinafter referred to as an “acrylic binder resin composition for a baked paste”). , An acrylic binder).

In the above-mentioned acrylic binder, the above-mentioned (A) acrylic (co) polymer comprises at least one monomer selected from alkyl (meth) acrylate monomers having 1 to 4 carbon atoms (hereinafter, referred to simply as a monomer). It is preferably (co) polymerized with 75 to 100%. In the acrylic binder, the monomer constituting the (A) acrylic (co) polymer is a hydroxyl group-containing (meth) acrylate monomer having a hydroxyl group (hereinafter referred to as monomer a-2). ) At a ratio of 10% by mass or less. In the acrylic binder, the monomer constituting the (A) acrylic (co) polymer is an unsaturated carboxylic acid monomer (hereinafter, sometimes referred to as monomer a-3). It may have 5% by mass or less.

In the acrylic binder, the thixotropic agent (B) may be a hydrogenated castor oil wax, a hydrogenated castor oil clay wax, a hydrogenated castor oil amide wax, a higher fatty acid nitrogen derivative wax, It is preferably at least one selected from the group consisting of fatty acid amide waxes and long chain fatty acid ester polymer waxes. Furthermore, it is preferable that the (C) organic solvent having a boiling point of 150 ° C. or higher contains terpineol at 50% by mass or more.

In the above-mentioned acrylic binder resin composition for a fired paste, the atmosphere in the atmosphere and / or
Alternatively, the amount of the pyrolysis residue can be reduced to 0.5% by mass or less under the firing conditions of heating to 450 ° C. at a rate of 10 ° C./min in an inert atmosphere.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The acrylic binder of the present invention comprises (B) 0.5 to 10 parts by mass of a thixotropic agent (A) with respect to 100 parts by mass of a thermoplastic acrylic (co) polymer having a weight average molecular weight of 40,000 to 100,000. Parts, (C) 100 to 400 parts by mass of an organic solvent having a boiling point of 150 ° C. or more.

The weight average molecular weight of the acrylic (co) polymer (A) is preferably from 40,000 to 100,000, more preferably from 50,000 to 80,000.
It is in the range of 0. By setting the weight-average molecular weight to 40,000 or more, the working viscosity during screen printing or dip coating can be ensured, and the weight-average molecular weight is 10
When the content is not more than 000, stringiness can be suppressed.

As the acrylic (co) polymer (A), (a-1) a monomer having 75 to 100% by mass of an alkyl (meth) acrylate monomer having 1 to 4 carbon atoms ( It is preferably obtained by copolymerization. The content of the monomer (a-1) in the acrylic (co) polymer (A) is preferably at least 75% by mass, more preferably at least 90% by mass, so that good sinterability is exhibited. You can do it. The above monomer (a-
Specific examples of 1) include methyl (meth) acrylate,
Mono (meth) acrylates such as ethyl (meth) acrylate, n-butyl (meth) acrylate, and i-butyl (meth) acrylate are exemplified. These can be used alone or in combination of two or more.

The monomer constituting the (A) acrylic (co) polymer is blended with (a-2) a hydroxy group-containing (meth) acrylate monomer having a hydroxyl group at a ratio of 10% by mass or less. You can do it. By using the monomer (a-2), it is possible to improve the viscosity of the acrylic binder and the dispersion stability of the metal pigment and the like, and at the same time, it is possible to obtain good thermal decomposability during firing. Also,
By setting the content to 10% by mass or less, the thermal decomposability during firing can be improved. In the monomer constituting the (A) acrylic (co) polymer, the monomer (a-
The content of 2) is preferably in the range of 0.1 to 10% by mass, and more preferably in the range of 3 to 5% by mass. Especially (C)
In the case where terpineol is used as the main component as the organic solvent, an increase in viscosity is observed, which has an effect of improving the viscosity of the acrylic binder.

The monomer (a-2) has 2 carbon atoms.
(Meth) acrylates containing one or more hydroxyl groups in the alkyl groups of to 8 are preferred. Specific examples include hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, and hydroxypropyl (meth)
Monohydroxy-containing (meth) acrylates such as acrylate, 1,2-dihydroxyethyl (meth) acrylate, 1,2-dihydroxypropyl (meth) acrylate, 1,2-dihydroxybutyl containing two hydroxyl groups in one molecule (Meth) acrylate, 1,2-dihydroxy-5-ethylhexyl (meth) acrylate, 1,2,3-trihydroxypropyl (meth) acrylate, 1,2,3-trihydroxybutyl (meth) acrylate, 1,1- Dihydroxyethyl (meth) acrylate, 1,1-dihydroxypropyl (meth) acrylate, 1,1-dihydroxybutyl (meth) acrylate, 1,1,2-trihydroxypropyl (meth) acrylate, 1,1,2-tri Hydroxybutyl (meth) acrylate, 1,2-dihydroxypropyl (meth)
Acrylate (glycerol (meth) acrylate);

Further, the monomers constituting the acrylic (co) polymer (A) include unsaturated carboxylic acid monomers (a-
3) can be blended at a ratio of 5% by mass or less. By blending the monomer (a-3), the dispersion stability of the filler dispersed in the acrylic binder can be improved, and at the same time, good thermal decomposability can be obtained during firing. Further, by setting the content to 5% by mass, the thermal decomposability during firing can be improved. In the monomer constituting the (A) acrylic (co) polymer, the content of the monomer (a-3) is 0.1 to
The range is preferably 5% by mass, more preferably from 0.1 to 2% by mass, even more preferably from 0.1 to 1% by mass. Specific examples of the monomer (a-3) include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, 2-methacryloyloxyethyl hexahydrophthalate, and 2-meracryloyloxy phthalate. Ethyl, 2-methacryloyloxyethyl maleate, 2-methacryloyloxyethyl succinate and the like.
A mixture of more than one species can be used.

The monomers constituting the (A) acrylic (co) polymer include a monomer (a-1), a monomer (a-2),
In addition to the monomer (a-3), a copolymerizable monomer (hereinafter, referred to as a monomer (a-4)) as an additive may be used as long as the firing property of the acrylic binder is not reduced. Further, it can be blended in a range of 10% by mass or less. Specific examples of the monomer (a-4) include alkyl (meth) acrylates having 5 or more carbon atoms, styrene, α-methylstyrene, acrylonitrile, acrylamide, methacrylamide, diethylaminoethyl (meth) acrylate,
Dimethylaminoethyl (meth) acrylate, allyl methacrylate, glycidyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, trimethylolpropane tri (meth) acrylate, polybutylene glycol dimethacrylate, 1,6 hexanediol dimethacrylate, 1,3 butylene glycol di Examples include methacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, and vinyl acetate.

As the thixotropic agent (B), any wax that imparts thixotropic properties can be used. In particular, hydrogenated castor oil-based wax, hydrogenated castor oil amide-based wax, hydrogenated castor oil clay Suitable waxes are higher waxes, higher fatty acid nitrogen derivative waxes, fatty acid amide waxes, and long-chain fatty acid ester waxes, and these can be used alone or in combination of two or more. The above (B) thixotropic agent is prepared by kneading 0.5 to 10 parts by mass with 100 parts by mass of the acrylic (co) polymer (A) by a method such as hot blending or a high-speed disperser and three rolls. Is preferred. (B) By adding 0.5 parts by mass or more of a thixotropic agent, a low molecular weight acrylic binder (polymer varnish) exhibits high viscosity and good printability. Further, when the amount is 10 parts by mass or less, the thermal decomposability is improved. The addition amount is preferably 2 to 8 parts by mass, more preferably 4 to 7 parts by mass.
Parts by weight. Since the viscosity of the thixotropic agent is a structural viscosity having thixotropic properties, it does not have stringiness as compared with a high-molecular-weight polymer, and has excellent screen printing and dip coating properties.

The organic solvent (C) has a boiling point of 150
Organic solvents at a temperature of at least ℃ are preferred. By setting the boiling point to 150 ° C. or higher, coating workability during screen printing or dip coating is improved. An organic solvent having a boiling point of less than 150 ° C. is not preferable because it is too fast to volatize and lacks continuous workability. As the addition amount of the (C) organic solvent,
(A) 100 parts by mass of acrylic (co) polymer
-400 parts by mass is preferred. (C) By adding the organic solvent in an amount of 100 parts by mass or more, (A) the acrylic (co) polymer can be uniformly dissolved and fluidity can be imparted, and at the same time, the filling rate of the filler can be improved. When the content is 400 parts by mass or less, a high viscosity with good thixotropy can be exhibited.

Specific examples of the organic solvent (C) include terpineol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether. , Diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2,2,4-trimethyl 1,3-pentadiol monoisobutyrate, isophorone, 3-methoxybutyl acetate, aromatic or aliphatic hydrocarbon having a boiling point of 150 ° C or higher Phthalates such as butyl lactate, dibutyl phthalate, dioctyl phthalate or dibutyl adipate, dioctyl adipate Plasticizers such as adipic acid esters such as bets and the like, can be used as a mixture of at least one or more kinds of these solvents. In particular, in order to exhibit high viscosity that enables screen printing and dip coating with the acrylic binder of the present invention, it is preferable that the organic solvent (C) contains at least 50% by mass of terpineol. More preferably, it is 80% by mass or more.

In addition, the acrylic binder includes
(D) additives include cellulose resins such as nitrocellulose, cellulose acetate butyrate, and ethyl cellulose, (co) polymers, leveling agents, pigment dispersants,
Auxiliary agents such as antifoaming agents should be used to satisfy viscosity stability during printing, paint sharpness, pigment dispersibility, recoating and halftone dot printing properties, defoaming properties, drying properties, firing properties, etc. Can be done. In this case, it is preferable to add the (D) additive in the range of 0.1 to 5 parts by mass. This is because by setting the amount to 5 parts by mass or less, the suitability for printing and firing tend to be improved, and more preferably in the range of 0.1 to 3 parts by mass.

The acrylic binder composed of such components is characterized in that there is little thermal decomposition residue such as sludge even in an atmosphere in the atmosphere and / or in an inert atmosphere, and 450 ° C. at a rate of 10 ° C./min. It is possible to reduce the amount of the pyrolysis residue to 0.5% by mass or less under the sintering condition by heating up to ° C. Conventionally, ethyl cellulose resin and butyral resin have a problem that a lot of residue called sludge is generated when firing at a low temperature of 450 ° C. or less, and further when the firing is performed in an inert atmosphere, more sludge is generated. It could not be used for parts requiring high purity quality, such as for use. On the other hand, according to the acrylic binder of the present invention, it is possible to use the acrylic binder under any firing conditions without causing the above-mentioned problems.

In the sintering paste obtained by mixing the acrylic binder and the filler, the acrylic binder is diluted with various organic solvents at the time of coating.
(A) It is preferable that the solid content of the acrylic (co) polymer is 10 to 60% by mass. (A) When the content of the acrylic (co) polymer is 10% by mass or more, the printability and firing properties are good, and the balance between the strength and the elongation of the coating film is good, and the content is 60% by mass or less. Thereby, the filling rate of the inorganic filler can be increased.

As a method for producing the above-mentioned acrylic binder, (A) an acrylic (co) polymer is first produced by a known method such as solution polymerization, suspension polymerization, emulsion polymerization and the like, and (B) a thixotropic agent. And other components are added and mixed. In the above solution polymerization, since a monomer is polymerized in a solvent, a binder resin solution can be obtained at the same time as the completion of the polymerization. In the above suspension polymerization, in order to polymerize a monomer suspension in water, an acrylic binder is produced by dissolving a bead-like acrylic (co) polymer in a solvent and adding and mixing other components. In the above emulsion polymerization, a monomer emulsified in water is polymerized in a micelle, so that an emulsified polymer ((A) acrylic (co)
(A) The acrylic (co) polymer obtained is dissolved in a solvent, and the other components are added and mixed to produce an acrylic binder. I do.

As the filler powder to be added to the acrylic binder, metal powders such as copper, silver, nickel, silver, and palladium can be used as the conductor, but are not particularly limited thereto. As a recent trend, the transition from expensive silver-based fillers to inexpensive copper and nickel-based fillers is progressing. Acrylic binders are preferred. In addition, the present invention can be applied to any application in which the binder resin is decomposed by firing and then formed by a sintering process, and is not limited to oxides such as alumina, zirconia, titanium oxide, barium titanate, alumina nitride, and silicon nitride. And phosphors such as nitrides such as boron nitride, silica-based powders such as low-melting glass powder, and the like. The mixing ratio of the filler powder and the acrylic binder is as follows.
The acrylic binder can be added so as to have a solid content of 3 to 30 parts by mass with respect to 00 parts by mass.
Since it differs depending on the specific gravity of the ceramic, it is not limited to the above range. If necessary, a plasticizer, a dispersing aid, and an antifoaming agent may be added. The coating method includes screen printing or dip coating for high viscosity applications, and a doctor blade method or cast method for low viscosity applications.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. In the examples, “parts” indicates “parts by mass”, and “%” indicates “% by mass”. (Example 1) (A) Production of acrylic (co) polymer 200 parts of terpineol was added to a 2 L four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas injection tube, and the temperature was raised to 90 ° C. did. Then, the internal temperature was set to 90 ° C., and i
-400 parts of butyl methacrylate, terpineol 12
0 parts, 2,2'-azobisisobutyronitrile (hereinafter AIB
After adding 0.7 part over 4 hours, 0.4 part of AIBN was added three times every hour, and this was kept for 1.5 hours. After the polymerization was completed, 592 parts of terpineol was added. Thus, an acrylic (co) polymer resin liquid having a solid content of 31% was obtained. The weight average molecular weight of the obtained resin solution was 50,000 as measured by GPC in terms of polystyrene. Next, the obtained (A) acrylic (co) polymer 10
The thixotropic agent (B), the organic solvent (C), and the additive (D) were added at a mixing ratio shown in Table 1 below with respect to 0 parts by mass, and the mixture was dispersed with a high-speed disperser to obtain an acrylic binder of Example 1. Was.

(Examples 2 to 5, Comparative Examples 1 to 5) Example 1
Acrylic (co) polymer resin liquid was prepared by changing the composition of acrylic (co) polymer (A) (shown as acrylic polymer (A) in the table) to the components shown in Table 1, and obtained Example 2 was prepared by adding the components shown in Tables 1 and 2 to the acrylic (co) polymer (A) in the same manner as in Example 1.
To 5 and Comparative Examples 1 to 4 were obtained.

The obtained acrylic binders of Examples 1 to 5 and Comparative Examples 1 to 4 were evaluated for acid value, sinterability and stringiness by the following methods. Filler dispersibility at that time, printability,
The clogging property and the like were evaluated. The results are shown in Tables 1 and 2.

<Acid Value> The number of mg of KOH required to neutralize 1 g of the acrylic polymer (solid content) (mg KOH / mg
g). <Firing property> The obtained acrylic binder resin was dried, and a sample amount of 10 to 20 mg was placed on an aluminum dish.
(Heat loss analysis). At this time, the temperature was raised from room temperature to 450 ° C. at a heating rate of 10 ° C./min in air, and then cooled to room temperature, and the state of the residue was observed. …: Thermal decomposition in a nitrogen atmosphere, complete decomposition without black or gray residue on aluminum plate. Heat loss rate 9
9.5% or more. …: Thermal decomposition in air atmosphere, complete decomposition without black or gray residue on aluminum plate. Heat loss rate 9
9.5% or more. Δ: Thermal decomposition in air atmosphere, black or gray residue on aluminum plate, poor decomposition products observed. Heat loss rate 95% to 99.5%. X: Thermal decomposition in air atmosphere, black or gray residue on aluminum plate, poor decomposition products observed. Heat loss rate of 95% or less.

<Stringiness> The viscosity was measured by changing the number of rotations when measuring the B-type viscosity. 6 rpm and 60 rpm
The viscosity at 6 rpm was measured and the viscosity at 6 rpm / 60 rpm
The viscosity ratio (thixotropic property) of the viscosity at m was determined, and the stringiness was evaluated as follows. It is considered that when this value is small, the stringing phenomenon easily occurs. ○: 4 or more, Δ: 2-3, ×: Less than 2

<Conversion of Conductor Paste>
5. The filler was mixed with the acrylic binders of Comparative Examples 1 to 4, and the characteristics were examined as a conductive paste. <Filler dispersibility> Obtained Examples 1 to 5, Comparative Examples 1 to
900 parts of copper powder was kneaded with 100 parts by mass of the acrylic binder of No. 4 using a three-roll mill to obtain a conductive paste. When the kneaded paste was solid-printed on a nylon 250-mesh screen, the obtained coating film had a smooth surface;
Those having the next aggregation were evaluated as x. In addition, those between ○ and × were marked with Δ. <Printability> When the conductor paste was printed on a 250-mesh screen made of nylon to form a fine line pattern with a line & space of 100 micrometers, a mark with good reproducibility of the line shape was marked with ○, and a mark with faint or crushed was marked with x. . In addition, those between ○ and × were marked with Δ. <Clogging> When the above-mentioned conductor paste was printed on a nylon 300 mesh screen, it was evaluated as ○ when the screen was well removed and not clogged, and x when clogged. In addition, those between ○ and × were marked with Δ.

[0033]

[Table 1]

[0034]

[Table 2]

The contents of the present invention represented by each embodiment are as follows. Example 1, Example 2 (acrylic composition modified product of Example 1), Example 3 (acrylic composition, thixotropic agent, solvent, solid content modified product), Example 4 (acrylic composition, solid content modified product), In Example 5 (solid content, acrylic composition changed product),
In any case, firing property, stringing property, filler dispersibility,
Both printability and clogging resistance were good.

Comparative Example 1 is an example in which the weight average molecular weight of the (A) acrylic (co) polymer was changed. (B) Despite the addition of the thixotropic agent, (A) the molecular weight of the acrylic (co) polymer was too high, resulting in poor stringing resistance, poor printability, and poor clogging resistance. Was.

Comparative Example 2 is an example in which no (B) thixotropic agent was added to the acrylic (co) polymer. Acrylic binder itself does not show structural viscosity, stringiness resistance,
Printability was poor.

In Comparative Example 3, the solvent used was a boiling point of 111 ° C.
This is an example of blending toluene. The drying property during printing was fast, and the printability and clogging resistance were poor.

Comparative Example 4 is an example in which (B) the thixotropic agent was added in an excessive amount of 12 parts with respect to 100 parts of the acrylic polymer. Although showing excessive structural viscosity, not only the leveling property of the coating film was poor, but also the thermal decomposition property was poor and black sludge was generated.

[0040]

As described above in detail, the acrylic binder according to the present invention contains (A) an acrylic (co) polymer having a relatively low molecular weight and (B) a thixotropic agent. Therefore, it is excellent in firing property (thermal decomposition property), has viscosity properties required for various processing methods, and has a viscous behavior without stringing. Therefore, when the above-mentioned acrylic binder is used as a binder for a firing paste, it has excellent thermal decomposability, excellent workability in various processing methods such as screen printing due to having a good high viscosity at a low solid content, and dispersion of a filler. A paste having good properties can be obtained.

If the acrylic (co) polymer (A) is obtained by (co) polymerizing a monomer having 75 to 100% by mass of the monomer (a-1), (A) An acrylic (co) polymer having a high molecular weight and excellent sinterability can be obtained, and the sinterability of the acrylic binder can be further improved. Further, as the acrylic (co) polymer (A), a monomer obtained by adding 10% by mass or less of the monomer (a-2) to the monomer having the monomer (a-1) is used. The use of one obtained by copolymerization can further improve the viscosity characteristics of the acrylic binder. Further, as the acrylic (co) polymer (A), a monomer having the monomer (a-1) or the monomer (a-1) and the monomer (a-2) may be used alone. The monomer (a-3) to 5
When a monomer obtained by copolymerizing a monomer added at a ratio of not more than mass% is used, the dispersion stability and firing property of the filler in the acrylic binder can be further improved.

The (B) thixotropic agent includes hydrogenated castor oil wax, hydrogenated castor oil clay wax, hydrogenated castor oil amide wax, higher fatty acid nitrogen derivative wax, fatty acid amide wax, and long chain. By using at least one selected from the group of fatty acid ester polymer-based waxes, the adhesive properties of the acrylic binder can be adjusted so that workability in various processing methods becomes good, and the stringing phenomenon can be further suppressed. I can do it.

When the organic solvent having a boiling point of 150 ° C. or more and containing terpineol at 50% by mass or more is used, the viscosity of the acrylic binder is made high enough to be suitable for screen printing or dip coating. I can do it.

In the above-mentioned acrylic binder, under the conditions of heating to 450 ° C. at a heating rate of 10 ° C./min in the atmosphere of air and / or an inert atmosphere, the pyrolysis residue is 0.5%. It can be used under firing conditions that conventional binders could not handle, and can be suitably used as a binder for a firing paste.

Claims (7)

[Claims] (A) a weight average molecular weight of 40,000 to 1
(B) 0.5 to 10 parts by mass of a thixotropic agent, relative to 100 parts by mass of a thermoplastic acrylic (co) polymer of
(C) 100 to 400 parts by mass of an organic solvent having a boiling point of 150 ° C. or more, an acrylic binder resin composition for a baked paste. 2. The method according to claim 1, wherein the thermoplastic acrylic (co) polymer (A) comprises at least one monomer selected from the group consisting of (a-1) an alkyl (meth) acrylate monomer having 1 to 4 carbon atoms.
The acrylic binder resin composition for a baked paste according to claim 1, wherein the acrylic binder resin composition has a content of 5 to 100% and is (co) polymerized. 3. The thermoplastic acryl (co) polymer (A) having (a-2) a hydroxy group-containing (meth) acrylate monomer having a hydroxyl group at a ratio of 10% by mass or less. 3. A polymerized product.
Acrylic binder resin composition for a sintering type paste according to 1. 4. The method according to claim 1, wherein (A) the thermoplastic acrylic (co) polymer is obtained by copolymerizing (a-3) an unsaturated carboxylic acid monomer in a proportion of 5% by mass or less. The acryl-based binder resin composition for a baked paste according to claim 2 or 3, wherein: 5. The (B) thixotropic agent is a hydrogenated castor oil wax, a hydrogenated castor oil clay wax, a hydrogenated castor oil amide wax, a higher fatty acid nitrogen derivative wax,
The acrylic binder resin composition for a fired paste according to any one of claims 1 to 4, wherein the acrylic binder resin composition is at least one selected from the group consisting of a fatty acid amide wax and a long-chain fatty acid ester polymer wax. 6. The fired paste according to claim 1, wherein the (C) organic solvent having a boiling point of 150 ° C. or higher contains terpineol at 50% by mass or more. Acrylic binder resin composition. 7. Under the sintering condition by heating up to 450 ° C. at a heating rate of 10 ° C./min in an atmosphere in the air and / or in an inert atmosphere, a pyrolysis residue is 0.5% by mass or less. The acrylic binder resin composition for a baked paste according to any one of claims 1 to 6, which is characterized in that: