JP7026888B2 - Conductive paste composition - Google Patents

Description

The present invention relates to a polymer which is excellent in thixotropy and pyrolysis property and is particularly suitable as a binder resin for a paste.

The metal paste used to form the internal electrode layer of laminated electronic components such as multilayer ceramic capacitors and the conductive layer of solar cells is mainly composed of metal powders such as nickel and copper, solvents, and binder resins, and screens. It is printed on the sheet by a method such as printing.

As shown in Patent Document 1, as the binder resin, an ethyl cellulose resin having high thixotropy property, no stringiness or bleeding during printing, and suitable for printing has been used. However, ethyl cellulose has a low thermal decomposition property, and carbon content remains at the time of firing, so that there is a problem that a large amount of heating residue leads to defects in the electrode.

On the other hand, although acrylic resin has excellent thermal decomposability, it has low thixotropy, and when the viscosity is increased, the stringiness becomes stronger, and when the viscosity is reduced to reduce the stringiness, bleeding occurs during printing. There was a problem that it was not suitable for printing. Here, the thixotropic property of the metal paste means a property that the apparent viscosity is low in a state where the shear rate is high, and the apparent viscosity is high in a state where the shear rate is low and a state where the shear rate is not sheared.

JP 2012-181988

In recent years, laminated devices such as multilayer ceramic capacitors have been made thinner and more multilayered for the purpose of miniaturization. However, as the thinning of the layer progresses, the problem that the influence of defects caused by the residual carbon content in the electrode layer becomes large during firing becomes apparent, and the thixotropy is excellent, there is no stringing or bleeding during printing, and printing is performed. There is a demand for a polymer suitable as a binder resin, which has properties suitable for the above, but is more excellent in pyrolysis and has a property of having a small residual carbon content.

In order to solve such a problem, a polymer having excellent thixotropy property, high printability without stringiness and bleeding during printing, excellent thermal decomposition property, and a small heat residue is required.

An object of the present invention is to provide a polymer having excellent thixotropic properties, no stringiness or bleeding during printing, and excellent thermal decomposability.

As a result of studies for solving the above-mentioned problems, the present inventor has found that the above-mentioned problems can be solved by a polymer having a specific structure having a hydroxyurethane structure.

（式（１）中、
Ｒ_１は、水素原子またはメチル基を示し、
Ｒ_２は、炭素数１～１８のアルキル基または炭素数１～１８のヒドロキシアルキル基を示し、
Ａは、炭素数１～１０のアルキレン基を示し、
Ｘは０または１を示し、
Ｙ_１は、下記式（２）および下記式（３）のヒドロキシウレタン構造からなる群より選ばれた一種以上の構造である。）
That is, the present invention is as follows.
[1] The molar ratio of the monomer (A) represented by the following formula (1) is 10 mol% to 100 mol%, and the molar ratio of the other monomer (B) copolymerizable with the monomer (A) is 0. A conductive paste composition comprising a polymer , an organic solvent and metal particles having a weight average molecular weight of 10,000 to 1,000,000 in an amount of about 90 mol%.

(In equation (1),
R ₁ represents a hydrogen atom or a methyl group.
_R2 represents an alkyl group having 1 to 18 carbon atoms or a hydroxyalkyl group having 1 to 18 carbon atoms.
A represents an alkylene group having 1 to 10 carbon atoms.
X indicates 0 or 1 and
Y ₁ is one or more structures selected from the group consisting of the hydroxyurethane structures of the following formula (2) and the following formula (3). )

[ 2 ] When the ratio of the metal particles is 100 parts by weight, the ratio of the polymer is 0.5 to 30 parts by weight, and the ratio of the organic solvent is 10 to 200 parts by weight. , [ 1 ] Conductive paste composition.

The polymer of the present invention has excellent solubility in a paste solvent, excellent thixotropy, no stringiness or bleeding during printing, and excellent thermal decomposability. As a result, the paste using the polymer of the present invention as the binder resin, particularly the metal paste, has high printability and can reduce the residual carbon content at the time of firing.

Hereinafter, embodiments of the present invention will be described.
[Monomer (A)]
The monomer (A) used in the present invention is represented by the following general formula (1).

In the formula (1), R ₁ is a hydrogen atom or a methyl group, and a methyl group is particularly preferable from the viewpoint of easiness of polymerization.

_R2 is an alkyl group having 1 to 18 carbon atoms or a hydroxyalkyl group having 1 to 18 carbon atoms. Examples of the alkyl group having 1 to 18 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an iso-butyl group, a tert-butyl group, an n-hexyl group and an n-octyl group. Examples thereof include 2-ethylhexyl group, decyl group, dodecyl group and stearyl group. From the viewpoint of ease of synthesis and thixotropy, the alkyl group constituting R2 preferably has ₂ to 12 carbon atoms, and more preferably 3 to 6 carbon atoms.

Examples of the hydroxyalkyl group having 1 to 18 carbon atoms include a hydroxymethyl group, a 2-hydroxyethyl group, a 3-hydroxypropyl group, a 2-hydroxypropul group, a 4-hydroxybutyl group, a 5-hydroxybutyl group, and 8 Examples thereof include a-hydroxyoctyl group and a 12-hydroxydodecyl group. From the viewpoint of ease of synthesis and thixotropic properties, the hydroxyalkyl group constituting R2 preferably has ₂ to 12 carbon atoms, more preferably 2 to 6 carbon atoms. ..

From the viewpoint of solubility in the paste solvent, it is more preferable that R ₂ is an alkyl group.

A is an alkylene group having 1 to 10 carbon atoms, preferably 6 or less carbon atoms, and more preferably 4 or less carbon atoms from the viewpoint of thixotropic properties.

X is 0 or 1, and 0 is preferable from the viewpoint of thixotropic property.

Y ₁ is one or more hydroxyurethane structures selected from the group consisting of the hydroxyurethane structures of the formulas (2) and (3). From the viewpoint of thixotropy, the structure of the formula (2) is particularly preferable.
As the monomer (A), one type may be used alone, or two or more types may be used in combination.

Among the monomers constituting the polymer, the molar ratio of the monomer (A) is 10 mol% or more. If the molar ratio of the monomer (A) is too low, the thixotropic property may be deteriorated. Therefore, the content is 10 mol% or more, preferably 15 mol% or more, and more preferably 20 mol% or more.

The molar ratio of the monomer (A) among the monomers constituting the polymer is 100 mol% or less. When the molar ratio of the monomer (A) is 100 mol%, the polymer of the present invention is a homopolymer, and when the molar ratio of the monomer (A) is less than 100 mol%, the polymer of the present invention is used. Becomes a copolymer. By setting the molar ratio of the monomer (A) to 50 mol% or less, the thermal decomposability of the polymer is further improved, but from this viewpoint, it is more preferably 40 mol% or less.

As the monomer (A), a hydroxyurethane structure of Y1 of the formula ( ₁ ) mixed with an isomer of the monomer (A) represented by the formulas (4) and (5) may be used. ..

[Monomer (B)]
The monomer (B) is a vinyl-based monomer copolymerizable with the monomer (A), and examples thereof include (meth) acrylic acid ester compounds, aromatic alkenyl compounds, vinyl cyanide compounds, and acrylamide compounds.

Examples of the (meth) acrylic acid ester compound include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, and n-. Examples thereof include hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, and stearyl (meth) acrylate.

Examples of the aromatic alkenyl compound include styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene and the like.

Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile.

Examples of the acrylamide compound include acrylamide and methacrylamide.

As the monomer (B), one type may be used alone, or two or more types may be used in combination. Among them, a (meth) acrylic acid ester compound is preferable from the viewpoint of solvent solubility and thermal decomposability, and a (meth) acrylic acid alkyl ester compound is particularly preferable. The alkyl group preferably has 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, further preferably 1 to 8 carbon atoms, and particularly preferably 1 to 4 carbon atoms. Methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and iso-butyl (meth) acrylate are most preferable.

In the monomer mixture, the total amount of the monomer (A) and the monomer (B) is 100 mol%. Therefore, the molar ratio of the monomer (B) is 0 to 90 mol%.

[Polymer]
The weight average molecular weight of the polymer of the present invention can be determined in terms of polystyrene using gel permeation chromatography (GPC), and is 10,000 to 1,000,000, preferably 10,000 to 800. 000, more preferably 30,000 to 300,000. If the weight average molecular weight of the polymer is too low, the strength and viscosity of the polymer may be insufficient, and if the weight average molecular weight is too high, solvent solubility and printability may decrease.

[Manufacturing method of monomer (A)]
The monomer (A) of the present invention is a monomer having a hydroxyurethane bond.
The monomer (A) can be obtained, for example, by an addition reaction between an amine compound and a compound having both a (meth) acryloyl group and a 5-membered ring carbonate group.

Compounds having both a (meth) acryloyl group and a 5-membered ring carbonate group used in the present invention are represented by the general formulas (6) and (7).

However, in the general formulas (6) and (7), R ₁ represents a hydrogen atom or a methyl group, R ₂ represents an alkyl group having 1 to 18 carbon atoms or a hydroxyalkyl group having 1 to 19 carbon atoms, and A represents an alkyl group having 1 to 19 carbon atoms. It represents an alkylene group having 1 or more carbon atoms and 10 or less carbon atoms, and X indicates 0 or 1. )

Specific examples of the compounds represented by the general formulas (6) and (7) include the following compounds (6-1) to (6-3) and (7-1).

The amine compound is preferably a primary amine compound or a secondary amine compound, and more preferably a primary amine compound.

The reaction between the 5-membered ring carbonate compound and the amine compound can be carried out by a known method by mixing the two and raising the temperature as desired. Further, if necessary, a known polymerization inhibitor may be added. It is desirable that this reaction be carried out at a temperature of 0 to 100 ° C, preferably 5 to 50 ° C. Further, the above reaction may be carried out using a solvent, for example, in the presence of acetone, methyl isobutyl ketone, ethyl acetate, butyl acetate, toluene, xylene, tetrahydrofuran and the like.

[Method for producing polymer]
Next, a method for producing the polymer of the present invention will be described.
The polymer in the present invention can be obtained by radically polymerizing a monomer mixture containing at least the monomer (A). The polymerization can be carried out by a known method. For example, solution polymerization, suspension polymerization, emulsion polymerization and the like can be mentioned, but solution polymerization and suspension polymerization are preferable in that the weight average molecular weight of the copolymer can be easily adjusted within the above range.

As the polymerization initiator, known ones can be used. For example, di (4-t-butylcyclohexyl) peroxydicarbonate, organic peroxides such as 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,2'-azobis. Examples thereof include an azo-based polymerization initiator such as isobutyronitrile. Only one kind of these polymerization initiators may be used, or two or more kinds thereof may be used in combination.
The amount of the polymerization initiator used can be appropriately set according to the combination of the monomers used, the reaction conditions, and the like.

When the polymerization initiator is added, for example, the entire amount may be charged in a batch, a part may be charged in a batch and the rest may be dropped, or the entire amount may be dropped. Further, it is preferable to add the polymerization initiator together with the monomer because the reaction can be easily controlled, and further, it is preferable to add the polymerization initiator after dropping the monomer because the residual monomer can be reduced.

As the polymerization solvent used in solution polymerization, a solvent in which the monomer and the polymerization initiator are dissolved can be used, and specifically, methanol, ethanol, 1-propanol, acetone, methyl ethyl ketone, propylene glycol monomethyl ether and the like can be used. Can be mentioned.

The concentration of the monomer (total amount) with respect to the polymerization solvent is preferably 10 to 60% by mass, particularly preferably 20 to 50% by mass. If the concentration of the monomer mixture is too low, the monomer tends to remain, and the molecular weight of the obtained copolymer may decrease. If the concentration of the monomer is too high, it may be difficult to control the heat generation.

When the monomer is added, for example, the entire amount may be charged in a batch, a part may be charged in a batch and the rest may be dropped, or the entire amount may be dropped. From the viewpoint of easy control of heat generation, it is preferable to prepare a part in a batch and drop the rest, or to drop the whole amount.

The polymerization temperature depends on the type of the polymerization solvent and the like, and is, for example, 50 ° C to 110 ° C. The polymerization time depends on the type of polymerization initiator and the polymerization temperature. For example, when di (4-t-butylcyclohexyl) peroxydicarbonate is used as the polymerization initiator, the polymerization is carried out at a polymerization temperature of 70 ° C. A suitable time is about 6 hours.

By carrying out the above polymerization reaction, a copolymer according to the resin composition of the present invention can be obtained. The obtained copolymer may be used as it is, or may be isolated by subjecting the reaction solution after the polymerization reaction to filtration or purification.

[Metal paste]
The polymer of the present invention is particularly suitable as a binder resin for metal pastes. The metal paste contains a metal powder and a solvent in addition to the polymer of the present invention.

Examples of such metal powders include platinum, gold, silver, copper, nickel, tin, palladium, aluminum and alloys of these metals. Of these, silver, copper, nickel and aluminum are preferable, and nickel is more preferable. The central particle size (D ₅₀ ) of the metal powder, that is, the cumulative volume particle size D50 measured by the laser diffraction / scattering type particle size distribution measuring device is preferably 0.05 μm to 50.0 μm. Of these, 0.06 μm to 10.0 μm is more preferable, 0.07 μm to 1.00 μm is further preferable, and 0.10 μm to 0.30 μm is particularly preferable. The particle size can be determined by a dynamic light scattering method or a laser diffraction type particle size distribution measuring device.

As the solvent, a hydrocarbon solvent such as toluene and xylene, an ester solvent such as ethyl acetate and butyl acetate, an alcohol solvent such as methanol, ethanol, isopropyl alcohol, isobutyl alcohol, 1-butanol and diacetone alcohol, and the like. Glycol ether solvents such as ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, glycol ether acetate solvents such as diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, tarpineol, dihydroterpineol , Tarpineol solvent such as dihydroterpineol acetate, and ketone solvent such as acetone, methyl ethyl ketone and methyl isobutyl ketone can be mentioned. Among these, glycol ether acetate-based solvent and tarpineol-based solvent are preferable, tarpineol-based solvent is more preferable, tarpineol or dihydrotarpineol is further preferable, and dihydroterpineol is particularly preferable. These can be used alone or in combination of two or more.

The content of the binder resin in the metal paste is preferably 0.5 to 30 parts by weight, more preferably 1 to 15 parts by weight, and further preferably 1 to 10 parts by weight when the weight of the metal powder is 100 parts by weight. It is preferable, and 1 to 5 parts by weight is particularly preferable. The content of the solvent in the metal paste is preferably 10 to 200 parts by weight, more preferably 50 to 150 parts by weight, still more preferably 75 to 125 parts by weight, when the weight of the metal powder is 100 parts by weight. .. In addition to this, other components such as a surfactant and an antioxidant can be blended as needed.

These mixtures are stirred and dispersed to give a metal paste. For stirring, known means can be used without particular limitation, and for example, a PD mixer or a planetary kneader can be used, and a planetary kneader is particularly preferable. For dispersion, known means can be used without particular limitation, and for example, a kneader, a bead mill, or a three-roll can be used, and a three-roll is particularly preferable.

The metal paste is printed on the sheet by a method such as screen printing.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.
Table 1 below shows the structure and abbreviation of the monomer (A).

(Synthesis Example 1: Monomer A1)
100 parts of glycidyl methacrylate (manufactured by Nichiyu Co., Ltd., trade name: Blemmer G) and lithium bromide (manufactured by Wako Pure Chemical Industries, Ltd.) as a catalyst in a reaction device equipped with a stirrer, thermometer, cooler, dropping funnel and gas introduction tube. ) 5 parts and 100 parts of N-methyl-2-pyrrolidone were added, carbon dioxide was continuously blown in while stirring, and the reaction was carried out at 100 ° C. for 12 hours. By gas chromatography (manufactured by Shimadzu Corporation, trade name: GC-2014, column DB-1), the progress of the reaction was confirmed by the disappearance of the peak of glycidyl methacrylate as a raw material. After completion of the reaction, 200 parts of toluene and 200 parts of water were added, mixed, and then allowed to stand to separate the aqueous layer. After removing the aqueous layer, it was washed 3 times with 100 parts of water. The washed organic layer was concentrated under reduced pressure to synthesize a 5-membered ring carbonate compound.

After adding 100 parts of dihydroterpineol to 100 parts of this 5-membered ring carbonate compound, the 5-membered ring carbonate compound and the equivalent amount of butylamine were added dropwise while controlling the internal temperature to 10 ° C. or lower while cooling and stirring. Then, the mixture was stirred for 2 hours. Gas chromatography (manufactured by Shimadzu Corporation, trade name: GC-2014, column DB-1) confirmed the progress of the reaction by the disappearance of the peak of the 5-membered ring carbonate compound.

The monomer A1 was obtained as an isomer mixture in which Y1 of the formula ( ₁ ) has the structures of the formulas (2) and (3), and after adjusting the monomer concentration to 50 wt%, it was used as it is for polymerization as a monomer solution.

(Synthesis Example 2: Monomer A2)
A 50 wt% solution of monomer A2 (mixed with isomers) was obtained by the same method as in Synthesis Example 1 except that the amine compound was changed from butylamine to 3-amino-1-propanol.

(Synthesis Example 3: Monomer A3)
A 50 wt% solution of monomer A3 (mixed with isomers) was obtained by the same method as in Synthesis Example 1 except that the amine compound was changed from butylamine to nonylamine.

(Synthesis Example 4: Monomer A4)
A 50 wt% solution of monomer A4 (mixed with isomers) was obtained by the same method as in Synthesis Example 1 except that glycidyl methacrylate was changed to 4-hydroxybutyl acrylate glycidyl ether (manufactured by Nihon Kasei Corporation, trade name: 4HBAGE). rice field.

(Synthesis Example 5: Monomer A5)
Monomer A5 (mixed with isomers) was prepared in the same manner as in Synthesis Example 1 except that glycidyl methacrylate was changed to 3,4-epoxycyclohexylmethyl methacrylate (manufactured by Daicel Corporation, trade name: Cyclomer M-100). A 50 wt% solution was obtained.

(Polymerization Example 1: Copolymer A)
350 g of dihydroterpineol was placed in a 1 L separable flask equipped with a stirrer, a thermometer, a cooler, a dropping funnel and a nitrogen introduction tube, and the inside of the flask was replaced with nitrogen to create a nitrogen atmosphere. Monomer solution obtained by mixing 151.3 g of isobutylmethacrylate (product name: Acryester IB (manufactured by Mitsubishi Rayon Co., Ltd.)) and 97.4 g of a 50% solution of monomer A1, and 50 g of dihydroterpineol and 2,2'-azobis (2). , 4-Dimethylvaleronitrile) (Product name: V-65 (manufactured by Wako Pure Chemical Industries, Ltd.)) 0.4 g was mixed to prepare a polymerization initiator solution.

The temperature inside the reaction vessel was raised to 75 ° C., and the monomer solution and the polymerization initiator solution were simultaneously added dropwise over 3 hours. Then, the reaction was carried out at 75 ° C. for 3 hours to obtain a dihydroterpineol solution of the copolymer A.

(Polymerization Example 2: Copolymer B)
Copolymer B was obtained by the same method as in Polymerization Example 1 except that the amount of isobutylmethacrylate used was changed to 112.3 g and the amount of the 50% solution of monomer A1 was changed to 175.5 g.

(Polymerization Example 3: Copolymer C)
The amount of isobutylmethacrylate used was changed to 70.8 g, the amount of 50% solution of monomer A1 used was changed to 258.3 g, and the amount of 2,2'-azobis (2,4-dimethylvaleronitrile) used was changed to 0.9 g. Copolymer C was obtained in the same manner as in Polymerization Example 1 except for the above.

(Polymerization Example 4: Copolymer D)
The amount of isobutylmethacrylate used was 111.9 g, the solution of monomer A1 was changed to the solution of monomer A2, 176.2 g was used, and the amount of 2,2'-azobis (2,4-dimethylvaleronitrile) used was 0.2 g. Copolymer D was obtained by the same method as in Polymerization Example 1 except that the above was changed to.

(Polymerization Example 5: Copolymer E)
The copolymer E was obtained by the same method as in Polymerization Example 1 except that the amount of isobutyl methacrylate used was 100.4 g and the solution of the monomer A1 was changed to the solution of the monomer A3 and 199.3 g was used.

(Polymerization Example 6: Copolymer F)
The copolymer F was obtained by the same method as in Polymerization Example 1 except that the amount of isobutyl methacrylate used was 102.2 g and the solution of the monomer A1 was changed to the solution of the monomer A4 and 195.6 g was used.

(Polymerization Example 7: Copolymer G)
Copolymer G was obtained by the same method as in Polymerization Example 1 except that the amount of isobutyl methacrylate used was 102.9 g and the solution of monomer A1 was changed to the solution of monomer A5 and 194.3 g was used.

(Polymerization Example 8: Copolymer H)
Copolymer H was prepared in the same manner as in Polymerization Example 1 except that the amount of isobutyl methacrylate used was 84.2 g, the amount of the solution of monomer A1 used was changed to 184.2 g, and 23.7 g of methyl methacrylate was used. Obtained.

(Polymerization Example 9: Copolymer I)
Copolymer I was obtained by the same method as in Polymerization Example 1 except that the amount of isobutylmethacrylate used was changed to 83.8 g, the amount of the solution of monomer A1 used was changed to 183.3 g, and 24.5 g of styrene was used. rice field.

(Polymerization Example 10: Copolymer J)
Copolymer J was obtained by the same method as in Polymerization Example 1 except that the amount of isobutylmethacrylate used was changed to 101.3 g, the amount of the solution of monomer A1 used was changed to 184.8 g, and 6.3 g of acrylonitrile was used. rice field.

(Polymerization Example 11: Copolymer K)
Copolymer K was obtained by the same method as in Polymerization Example 1 except that the amount of isobutylmethacrylate used was changed to 100.2 g, the amount of the solution of monomer A1 used was changed to 182.8 g, and 8.4 g of acrylamide was used. rice field.

(Polymerization Example 12: Copolymer L)
The copolymer L was obtained by the same method as in Polymerization Example 1 except that the amount of isobutylmethacrylate used was changed to 182.5 g and the amount of the solution of the monomer A1 used was changed to 35.0 g.

(Polymerization Example 13: Copolymer M)
Copolymer M was obtained by the same method as in Polymerization Example 1 except that 143.7 g of isobutyl methacrylate was used and 56.3 g of 2-hydroxyethyl methacrylate was used instead of the monomer A1.

[Measurement of weight average molecular weight]
The weight average molecular weight of the copolymers A to M was determined by gel permeation chromatography (GPC) under the following conditions.
Equipment: HLC-8220 manufactured by Tosoh Corporation
Column: LF-804 manufactured by shodex
Standard substance: Polystyrene Eluent: THF (tetrahydrofuran)
Flow rate: 1.0 ml / min
Column temperature: 40 ° C
Detector: RI (Differential Refractometer)

[Evaluation of thixotropy]
A 20 wt% copolymer solution (solvent dihydroterpineol) was prepared and the shear rate dependence of viscosity was measured in the range of 1s-1 to 1,000s-1 with a leometer. The ratio of viscosities at 1s-1 and 1,000s-1 was calculated as a TI value.

[Evaluation of pyrolysis]
5 mg of the copolymer was placed in an aluminum pan, and the temperature was raised to 500 ° C. at a heating rate of 10 ° C./min under an air atmosphere with TG / DTA, and the residual amount of the sample was measured.

[Evaluation of printability]
To 100 parts by weight of Ni powder (manufactured by JFE Mineral: NFP201S), add 1 part by weight of oleoyl zarcosin (manufactured by NOF: Eslim 221P), 3 parts by weight of binder resin, and 90 parts by weight of dihydroterpineol. These mixtures were stirred using a planetary kneader and then kneaded with three rolls to obtain a Ni paste.

The obtained Ni paste was screen-printed, and the obtained printed matter was confirmed with an optical microscope, and visually confirmed whether there was any bleeding or traces of stringing. If no bleeding or stringing was seen, it was marked as "○" (good), and if bleeding or threading was seen, it was marked as "x" (bad).

In Examples 1 to 11, the thixotropy value was high, the heating residue was small, and the printability was high.

In Comparative Example 1, the ratio of the monomer A1 was less than 10 mol%, the heating residue was small, but the thixotropy value was low and the printability was also low.

In Comparative Example 2, a copolymer containing no monomer of the present invention was used, and although the heating residue was small, the thixotropy value was low and the printability was also low.

In Comparative Example 3, ethyl cellulose was used, but the thixotropy value was large and the printability was high, but the heating residue was large.

Claims (2)

The molar ratio of the monomer (A) represented by the following formula (1) is 10 mol% to 100 mol%, and the molar ratio of the other monomer (B) copolymerizable with the monomer (A) is 0 to 90 mol. %, A conductive paste composition comprising a polymer having a weight average molecular weight of 10,000 to 1,000,000, an organic solvent and metal particles .

(In equation (1),
R ₁ represents a hydrogen atom or a methyl group.
_R2 represents an alkyl group having 1 to 18 carbon atoms or a hydroxyalkyl group having 1 to 18 carbon atoms.
A represents an alkylene group having 1 to 10 carbon atoms.
X indicates 0 or 1 and
Y ₁ is one or more structures selected from the group consisting of the hydroxyurethane structures of the following formula (2) and the following formula (3). )

The claim is characterized in that, when the ratio of the metal particles is 100 parts by weight, the ratio of the polymer is 0.5 to 30 parts by weight, and the ratio of the organic solvent is 10 to 200 parts by weight. 1. The conductive paste composition according to 1.