阅读说明：本技术 导电性糊用溶剂组合物、载体和导电性糊 (Solvent composition for conductive paste, carrier, and conductive paste ) 是由 本田绘里 高田茂人 道田实 于 2019-09-25 设计创作，主要内容包括：本发明提供一种用于制造不发生电特性劣化的多层陶瓷部件的、不发生因片侵蚀现象而引起的层间剥离、蒸发干燥容易、而且具备适度的粘度特性的导电性糊用溶剂组合物、利用其的载体和导电性糊。所述导电性糊用溶剂组合物含有(A)单萜烯醇和/或单萜烯脂肪酸酯、以及(B)乳酸烷基酯。(The invention provides a solvent composition for conductive paste, a carrier and a conductive paste using the same, wherein the solvent composition is used for manufacturing a multilayer ceramic component without electric characteristic deterioration, does not generate interlayer peeling caused by sheet erosion phenomenon, is easy to evaporate and dry, and has appropriate viscosity characteristic. The solvent composition for conductive paste contains (A) monoterpene alcohol and/or monoterpene fatty acid ester and (B) alkyl lactate.)

1. A solvent composition for conductive paste, which contains (A) monoterpene alcohol and/or monoterpene fatty acid ester and (B) alkyl lactate.

2. The solvent composition for conductive paste according to claim 1, further comprising (C) a terpene-based hydrocarbon.

3. The solvent composition for conductive paste according to claim 1 or 2, wherein the component (A) is 1 or 2 or more selected from the group consisting of terpineol, dihydroterpineol, terpineol acetate, dihydroterpineol acetate, isobornyl propionate, isobornyl butyrate, and isobornyl isobutyrate.

4. The solvent composition for electroconductive paste according to any one of claims 1 to 3, wherein the component (B) is 1 or 2 or more selected from the group consisting of methyl lactate, ethyl lactate, n-propyl lactate, isopropyl lactate, n-butyl lactate, isobutyl lactate, amyl lactate, hexyl lactate, octyl lactate, and 2-ethylhexyl lactate.

5. The solvent composition for conductive paste according to any one of claims 2 to 4, wherein the component (C) is selected from the group consisting of α -pinene, β -pinene, pinane, 3-carene, carane, camphene, fenchyne, dipentene, limonene, α -terpinene, γ -terpinene, α -phellandrene, β -phellandrene, terpinolene, 1-p-terpinoleneEne, p1 or more than 2 kinds of alkane, p-cymene, sabinene, myrcene, dihydromyrcene, alloocimene and 2, 6-dimethyloctane.

6. The solvent composition for conductive paste according to any one of claims 1 to 5, wherein the proportions of each of the components (A) to (C) are, based on 100 parts by weight of the total of the components (A), (B) and (C): (A)10 to 90 parts by weight, (B)5 to 70 parts by weight, and (C)0 to 85 parts by weight.

7. A carrier comprising the solvent composition for conductive paste according to any one of claims 1 to 6 and a binder resin.

8. The carrier according to claim 7, wherein the binder resin contains at least 1 selected from the group consisting of a cellulose-based resin, a butyral resin, and an acrylic resin.

9. A conductive paste comprising the carrier according to claim 7 or 8 and a conductive powder.

Technical Field

The present invention relates to a solvent composition for conductive paste used in the production of a multilayer ceramic component such as a multilayer ceramic capacitor or a multilayer ceramic substrate, a carrier in which a binder resin is mixed in the solvent composition for conductive paste, and a conductive paste in which a conductive powder is mixed in the carrier.

Background

The multilayer ceramic component is obtained by: a dielectric paste is applied to a carrier film by a doctor blade method or the like to form a ceramic green sheet, a conductive paste is printed on the green sheet (green sheet), an internal electrode is formed by drying, then, an external electrode is applied to a ceramic laminate obtained by stacking and sintering several tens to several hundreds layers on the obtained green sheet, and baking is performed.

As the conductive paste, a conductive paste obtained by mixing and dispersing a conductive material such as metal powder of copper, silver, gold, platinum, nickel, palladium, or the like, a binder resin such as ethyl cellulose resin or alkyd resin, and a solvent such as terpineol, can be used.

In recent years, with the miniaturization, thinning and high functionality of various information devices, further miniaturization and high capacity of multilayer ceramic parts have been demanded, and in order to meet this demand, various methods of reducing the thickness of each of the laminated layers and increasing the number of laminated layers have been studied.

However, as the thickness of the laminate becomes thinner, the influence of a phenomenon called "sheet erosion" in which a solvent in the conductive paste dissolves a resin binder such as a polyvinyl butyral resin contained in the ceramic green sheet to generate wrinkles or holes in the ceramic green sheet becomes remarkable, and the performance of the multilayer ceramic part is degraded.

As a method for solving this problem, patent document 1 proposes a hydrogenated terpineol, patent document 2 proposes isobornyl acetate and/or nopyl acetate, and patent document 3 proposes a solvent for conductive paste using a hydrogenated terpene such as hydrogenated terpineol acetate or an ester compound of a terpene obtained by reacting a terpene with a carboxylic acid. However, these solvents still have high solubility in the polyvinyl butyral resin, and it is difficult to completely suppress the sheet erosion phenomenon.

On the other hand, in order to reduce such adverse effects on the green sheet (green sheet), attempts have been made to lower the drying temperature of the solvent, and to shorten the drying time in order to shorten the time required for the steps due to the increase in the number of stacked layers. As a result, the solvent having a high boiling point as described above is insufficiently dried, and the solvent remaining in the internal electrode volatilizes during firing, causing problems such as delamination and cracking.

On the other hand, for example, patent document 4 discloses that 1-pair is contained as a solvent componentEne, pAnd conductive paste such as alkane. These solvents have low solubility in a butyral resin used in a ceramic green sheet, and therefore can suppress a sheet erosion phenomenon, and are also applicable to a high-speed printing method such as gravure printing because of a high evaporation rate. However, since these solvents have low solubility in binder resins such as ethyl cellulose, there are cases where: it is difficult to produce a conductive paste having a suitable viscosity required for a printing method such as screen printing or gravure printing, or a problem is likely to occur during printing due to a change in viscosity of the conductive paste with time.

Further, patent document 5 discloses a conductive paste containing, in a specific ratio: a hydrocarbon solvent containing 30% by weight or more of a naphthenic hydrocarbon and a solvent other than the hydrocarbon solvent such as an alcohol solvent. The conductive paste can suppress the sheet erosion phenomenon and has excellent paste stability, but the solubility of the binder resin is still low, and a conductive paste having a viscosity suitable for printing may not be obtained.

Documents of the prior art

Patent document

Patent document 1: japanese unexamined patent publication Hei 7-21832

Patent document 2: japanese laid-open patent publication No. 2002-270456

Patent document 3: japanese unexamined patent publication Hei 7-21833

Patent document 4: japanese laid-open patent publication No. 2003-249121

Patent document 5: japanese unexamined patent application publication No. 2007-19122

Disclosure of Invention

Problems to be solved by the invention

The purpose of the present invention is to provide a solvent composition for a conductive paste, which is easy to evaporate and dry and has appropriate viscosity characteristics, and which is used for producing a multilayer ceramic component that does not suffer from deterioration in electrical characteristics, a carrier using the same, and a conductive paste. It is another object of the present invention to provide a solvent composition for conductive paste, a carrier using the same, and a conductive paste, which have the above characteristics and can suppress interlayer peeling due to a sheet erosion phenomenon.

Means for solving the problems

The present invention is constituted by the following inventions 1 to 9.

< invention 1>

A solvent composition for conductive paste, which contains (A) monoterpene alcohol and/or monoterpene fatty acid ester and (B) alkyl lactate.

< invention 2>

The solvent composition for conductive paste according to invention 1 further contains (C) a terpene-based hydrocarbon.

< invention 3>

The solvent composition for conductive paste according to claim 1 or 2, wherein the component (a) is 1 or 2 or more selected from the group consisting of terpineol, dihydroterpineol, terpineol acetate, dihydroterpineol acetate, isobornyl propionate, isobornyl butyrate and isobornyl isobutyrate.

< invention 4>

The solvent composition for electroconductive paste according to any one of claims 1 to 3, wherein the component (B) is 1 or 2 or more selected from the group consisting of methyl lactate, ethyl lactate, n-propyl lactate, isopropyl lactate, n-butyl lactate, isobutyl lactate, amyl lactate, hexyl lactate, octyl lactate and 2-ethylhexyl lactate.

< invention 5>

The solvent composition for conductive paste according to any one of claims 2 to 4, wherein the component (C) is selected from the group consisting of α -pinene, β -pinene, pinane, 3-carene, camphene, and mixtures thereof,Fenchene, dipentene, limonene, alpha-terpinene, gamma-terpinene, alpha-phellandrene, beta-phellandrene, terpinolene, 1-p-terpineneEne, p1 or more than 2 kinds of alkane, p-cymene, sabinene, myrcene, dihydromyrcene, alloocimene and 2, 6-dimethyloctane.

< invention 6>

The solvent composition for conductive paste according to any one of claims 1 to 5, wherein the proportions of each of the components (A) to (C) are, based on 100 parts by weight of the total of the components (A), (B) and (C): (A)10 to 90 parts by weight of (B)5 to 70 parts by weight of (C)0 to 85 parts by weight of (C),

< invention 7>

A carrier comprising the solvent composition for conductive paste according to any one of claims 1 to 6 and a binder resin.

< invention 8>

The carrier according to claim 7, wherein the binder resin contains at least 1 selected from the group consisting of a cellulose resin, a butyral resin, and an acrylic resin.

< invention 9>

A conductive paste comprising the carrier according to claim 7 or 8 and a conductive powder.

Effects of the invention

The conductive paste using the solvent composition of the present invention can suppress the sheet erosion phenomenon as compared with conventional conductive pastes, and can produce a multilayer ceramic component without deterioration of electrical characteristics because of its low boiling point and low viscosity.

Detailed Description

< solvent composition for conductive paste >

The solvent composition for conductive paste of the present invention contains (a) monoterpene alcohol and/or a monoterpene fatty acid ester and (B) alkyl lactate. The solvent composition for conductive paste of the present invention may further contain (C) a terpene hydrocarbon.

The components (A), (B) and (C) will be described below.

Monoterpene alcohol and fatty acid monoterpene ester

The monoterpene alcohol and/or the monoterpene fatty acid ester (A) of the present invention is represented by the formula (C)₅H₈)₂A compound represented by formula (I) wherein at least 1 hydrogen atom of the monoterpene hydrocarbon is substituted with a hydroxyl group or a fatty acid residue. Here, the monoterpene hydrocarbon preferably has 1 or more alicyclic skeletons. The degree of unsaturation of the monoterpene olefin is not particularly limited, and multiple bonds in the compound may be hydrogenated or may contain an aromatic ring. The fatty acid is preferably a saturated fatty acid and is a carboxylic acid having 2 to 6 carbon atoms.

The boiling point of component (A) of the present invention at normal pressure is 50 ℃ or higher and 300 ℃ or lower, preferably 100 ℃ or higher and 250 ℃ or lower. When the boiling point is less than 50 ℃, the drying rate of the solvent may be too high and the paste stability may be deteriorated, while when the boiling point exceeds 300 ℃, the drying rate of the solvent may be too low and the electrical characteristics may be impaired by the remaining solvent, which is not preferable.

Specific examples of the component (A) in the present invention include terpineol, dihydroterpineol, terpineol acetate, dihydroterpineol acetate, isobornyl propionate, isobornyl butyrate, isobornyl isobutyrate, norbomyl acetate, and the like, and 2 or more of them may be used alone or in combination.

Alkyl lactate (B)

The alkyl lactate (B) in the present invention is a lactate having an alkyl group with 8 or less carbon atoms, and examples thereof include methyl lactate, ethyl lactate, n-propyl lactate, isopropyl lactate, n-butyl lactate, isobutyl lactate, pentyl lactate, hexyl lactate, octyl lactate, and 2-ethylhexyl lactate. Among them, preferred are lactic acid esters having an alkyl group having 5 or less carbon atoms, such as methyl lactate, ethyl lactate, n-propyl lactate, isopropyl lactate, n-butyl lactate, isobutyl lactate, and pentyl lactate, and the alkyl group may be linear or branched. When the number of carbons of the alkyl group exceeds 8, the drying rate may be too slow, which is not preferable.

The boiling point of component (B) of the present invention at normal pressure is in the range of 100 ℃ to 300 ℃, preferably 120 ℃ to 250 ℃. When the boiling point is less than 100 ℃, the drying rate of the solvent may be too high and the stability of the paste may be deteriorated, while when the boiling point exceeds 300 ℃, the drying rate of the solvent may be too low and the residual solvent may volatilize during firing to cause delamination or deteriorate the printing accuracy, which is not preferable.

The alkyl lactate of the present invention can be produced by a known method, and is not particularly limited, and can be obtained by, for example, a dehydration condensation reaction of lactic acid and alcohol, a transesterification reaction of a lactate ester and alcohol, or the like. Lactic acid to be used as a raw material may be lactic acid produced by any method such as a fermentation method or a synthesis method, and lactic acid produced by a fermentation method is preferable from the viewpoint of reducing environmental load.

[ terpene-based hydrocarbon (C) ]

The terpene-based hydrocarbon (C) of the present invention is represented by the formula (C)₅H₈)_nThe compounds represented by the formula are monoterpene hydrocarbon compounds having n ═ 2. The degree of unsaturation of the compound is not particularly limited, and the multiple bond in the compound may be hydrogenated or may contain an aromatic ring.

The boiling point of the terpene-based hydrocarbon of the present invention at normal pressure is 50 ℃ or higher and 250 ℃ or lower, preferably 100 ℃ or higher and 200 ℃ or lower. When the boiling point is less than 50 ℃, the drying rate of the solvent may be too high and the stability of the paste may be deteriorated, while when the boiling point exceeds 250 ℃, the drying rate of the solvent may be too low and the electrical characteristics of the remaining solvent may be impaired, which is not preferable.

Specific examples of the terpene-based hydrocarbon of the present invention include α -pinene, β -pinene, pinane, 3-carene, camphene, fenchene, dipentene, limonene, α -terpinene, γ -terpinene, α -phellandrene, β -phellandrene, terpinolene, 1-p-phellandreneEne, pAlkane, p-cymene, sabinene, myrcene, dihydromyrcene, alloocimene, 2, 6-dimethyloctane and the like, which may be used alone or in combination of 2 or more.

The solvent composition for conductive paste of the present invention contains the component (C), whereby the sheet erosion phenomenon can be further suppressed, and the drying rate can be increased by reducing the viscosity of the conductive paste.

The mixing ratio of the components (a), (B) and (C) constituting the solvent composition for conductive paste of the present invention is not particularly limited, but is preferably 10 to 90 parts by weight of (a), (B)5 to 70 parts by weight of (B) and (C)0 to 85 parts by weight of (C), more preferably 10 to 70 parts by weight of (a), (B)5 to 50 parts by weight of (B) and (C)0 to 85 parts by weight, based on 100 parts by weight of the total of the components (a), (B) and (C).

When the amount of the component (B) exceeds 70 parts by weight, the sheet erosion phenomenon may become remarkable, and thus it is not preferable. Even if the amount of the component (B) is 70 parts by weight or less, if the amount of the component (a) is less than 10 parts by weight, the balance between the viscosity and the drying rate of the obtained paste may be insufficient, or the stability at low temperature may be deteriorated. On the other hand, when the amount of the component (A) exceeds 90 parts by weight (and the amount of the component (B) is less than 5 parts by weight), the effect of improving the viscosity characteristics and the drying rate is not good.

When the amount of the component (C) exceeds 85 parts by weight, the solubility of the binder resin in the solvent composition is lowered, and the viscosity of the paste is remarkably lowered, which is not preferable.

The components (a) to (C) constituting the solvent composition of the present invention are all solvents derived from terpene compounds or lactic acid which are renewable natural resources, and they are less toxic than petroleum-derived solvents and contribute to a reduction in environmental load.

The solvent composition of the present invention may further contain, if necessary, an additive such as an antioxidant, and other solvents generally used for conductive pastes or dielectric pastes. Examples of other solvents generally used for the conductive paste or the dielectric paste include, but are not limited to, glycol solvents such as ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, and dipropylene glycol methyl ether acetate, hydrocarbon solvents such as hexane, cyclohexane, heptane, octane, nonane, decane, decalin, and toluene, and alcohol solvents such as ethanol, propanol, butanol, hexanol, heptanol, octanol, nonanol, and decanol.

< Carrier, conductive paste >

The carrier and the conductive paste of the present invention will be described below.

The vehicle of the present invention comprises the solvent composition of the present invention and a binder resin. In addition, since the conductive paste of the present invention corresponds to the internal electrode layer, the conductive powder is dispersed in the support of the present invention.

As the binder resin, a cellulose-based resin such as ethyl cellulose or nitrocellulose, an acetal-based resin such as polyvinyl butyral, an acrylic resin obtained by polymerizing butyl methacrylate, methyl methacrylate, or the like can be used. As the binder resin used for the conductive paste, ethyl cellulose is preferable.

The method for producing the carrier of the present invention is not particularly limited, and the carrier can be produced by a conventionally known method. The order of mixing and dissolving components (a) to (B) or components (a) to (C) constituting the solvent composition and the binder resin is not particularly limited, and may be mixed and dissolved in any order. For example, the binder resin may be dissolved in a solvent composition in which components (a) to (B) or components (a) to (C) are mixed, or the binder resin may be dissolved in a specific solvent component in advance, and then the remaining solvent component may be mixed.

The carrier is mainly composed of a solvent composition and a binder resin, and the proportion of the solvent composition in the carrier is not particularly limited, but is preferably 60 to 98% by weight. More preferably 70 to 95% by weight. When the amount is less than 60% by weight, the solubility of ethyl cellulose or the like may be poor, or the viscosity of the carrier may be too high. On the other hand, when the amount exceeds 98% by weight, the viscosity of the carrier may become too low, which is not preferable.

The method for producing the conductive paste of the present invention is not particularly limited, and the conductive paste can be produced by a conventionally known method. The order of mixing and dissolving the components (a) to (B) or the components (a) to (C), the binder resin, and the conductive powder constituting the solvent composition is not particularly limited, and the components may be mixed and dissolved in any order. For example, the conductive powder may be dissolved in a carrier in which components (a) to (B) or components (a) to (C) and a binder resin are mixed and dissolved; it can also be prepared by mixing and dissolving a specific solvent component, a binder resin and a conductive powder in advance and then mixing the remaining solvent component.

As the conductive powder to be mixed with the carrier to form the conductive paste, metal powder such as copper, silver, gold, platinum, nickel, palladium, or the like can be used. More preferably platinum powder, nickel powder, or palladium powder.

The proportion of the conductive powder in the conductive paste is not particularly limited, and is usually 30 to 95% by weight, preferably 40 to 80% by weight. When the content is less than 30% by weight, the packing density of the conductive powder may become low, which is not preferable, and when the content exceeds 95% by weight, the viscosity of the paste may increase, which may result in significant deterioration of productivity.

The proportion of the carrier in the conductive paste is preferably 5 to 70 wt%. More preferably 20 to 60% by weight. When the support is less than 5% by weight, the strength of the dried film becomes weak, while when the support exceeds 70% by weight, the thickness of the electrode after sintering becomes too thin, which is not preferable.

The conductive paste of the present invention may further contain an antioxidant, a surfactant, a dispersant, a filler, a plasticizer, a reactive monomer, and the like in addition to the solvent, the binder resin, and the conductive powder.

Examples

The present invention will be described more specifically below with reference to examples.

Example 1

A solvent composition was prepared by mixing 90 parts by weight of terpineol (manufactured by Anyun chemical Co., Ltd.) and 10 parts by weight of ethyl lactate (manufactured by Corbion Japan Co., Ltd., PURASOLV EL). To 95 parts by weight of the solvent composition, 5 parts by weight of ethyl cellulose (made by dow chemical corporation, ETHOCEL200) was added, and a carrier was prepared using a planetary stirring/defoaming device (made by sank textile co., マゼルスター). 100 parts by weight of nickel powder (particle size 0.3 μm) and 10 parts by weight of barium titanate (particle size 0.1 μm) were added to 100 parts by weight of the carrier, and a conductive paste was prepared using a planetary stirring/defoaming device.

The solvent composition, the vehicle, and the conductive paste thus prepared were evaluated as follows. The evaluation results are shown in Table 1.

The viscosity, drying time, butyral resin solubility, and sheet corrosion resistance were measured as follows.

(viscosity)

The viscosity of the carrier at 20 ℃ was measured with a type B viscometer. The case where the viscosity was less than 5,000mPa · s was expressed as ". circa", the case where the viscosity was 5,000mPa · s or more and less than 50,000mPa · s was expressed as ". smallcircle", and the case where the viscosity was 50,000mPa · s or more was expressed as "×".

(drying time)

The time taken for the solvent composition to lose 50% (50% loss time) under a temperature condition of 120 ℃ was measured using a thermogravimetric apparatus (TA Instruments Co., Ltd.).

The case where the time for 50% reduction was less than 5 minutes was indicated as "very excellent", the case where the time was 5 minutes or more and less than 20 minutes was indicated as "o", and the case where the time was 20 minutes or more was indicated as "x".

(solubility of butyral resin)

A50 mL stoppered tube was charged with 1,000mg of a butyral resin (product of Sumitomo chemical Co., Ltd., trade name S-LEC SV-05) and 12.5g of the solvent composition of the present invention, and the mixture was heated at 60 ℃ for 2 hours while being stirred by a stirrer. After completion of the warming, the supernatant was separated and centrifuged at 2,000rpm for 5 minutes. A sample was prepared so that the amount of a standard (アデカスタブ AO-330, manufactured by ADEKA) was 20mg and the amount of tetrahydrofuran was 10mL based on 1g of the supernatant of the obtained product, and GPC was measured.

The measurement of GPC was performed under the following conditions.

The device comprises the following steps: model 510 manufactured by Waters corporation

Column: TSKgel manufactured by Tosoh corporation (G2000H 8X 2 and G3000HXL 1)

Eluent: tetrahydrofuran (THF)

Sample introduction amount: 250 μ L

Flow rate: 1.0 mL/min

After the measurement, the amount (mg) of the butyral resin dissolved in 12.5g of each solvent was calculated from the ratio of the peak area corresponding to the molecular weight of the butyral resin to the peak area of the standard.

When the butyraldehyde resin amount is less than 100mg, the excellent property is judged, when the butyraldehyde resin amount is 100mg or more and less than 600mg, the good property is judged, and when the butyraldehyde resin amount is 600mg or more, the poor property is judged.

(sheet-erodibility)

The conductive paste obtained above was screen-printed on a green sheet having a thickness of 2 μm made of barium titanate and polyvinyl butyral, dried at 80 ℃ for 5 minutes, and then the surface was observed with a solid microscope to confirm the presence or absence of cracks and wrinkles.

The ceramic green sheet was judged as "excellent" when no cracks or wrinkles were observed, as "o" when no cracks were observed but wrinkles were observed, and as "x" when cracks were observed.

Examples 2 to 18 and comparative examples 1 to 5

A solvent composition, a vehicle, and a conductive paste were prepared in the same manner as in example 1, except that the compositions of the solvents were as shown in tables 1 to 2. The solvent composition, the vehicle, and the conductive paste thus prepared were evaluated in the same manner as in example 1. In comparative example 4, since ethyl cellulose was not completely dissolved in the solvent and no carrier could be produced, the viscosity and the sheet-erodibility were defined as "-".

As shown in tables 1 to 2, the solvent composition for conductive paste of the present invention has a lower viscosity and a higher drying rate than terpineol or dihydroterpineol, which are used as conventional paste solvents. Further, the butyral resin has lower solubility than ethyl lactate, and can suppress the sheet erosion phenomenon.

Industrial applicability

The conductive paste using the solvent composition for a conductive paste of the present invention can be used as a paste used in the production of a multilayer ceramic component such as a multilayer ceramic capacitor.