TW202341185A - Conductive composition - Google Patents

Abstract

Provided is a conductive composition which is not susceptible to changes in viscosity characteristics during storage and which is capable of forming a metal film having good adhesion to an inorganic base material and good solder wettability. The conductive composition contains (a) a glass frit, (b) an alicyclic alcohol having 7-18 carbon atoms, and (c) conductive particles, and contains 0.5-20% by mass of component (a), 0.5-15% by mass of component (b), and 65-99% by mass of component (c) per 100% by mass of the total of components (a)-(c).

Description

Conductive composition

The present invention relates to conductive compositions.

In recent years, from the viewpoint of reducing the amount of chemical substances used and discharged, the conventional plating method that uses a large amount of chemical liquid and requires many steps has gradually been replaced by the use of a screen as a method of forming electrodes in electronic parts. Printing methods for printing presses, etc.

Among them, electrode formation technology using screen printing using a commonly used printing method is actively developed, and conductive pastes suitable for screen printing are also actively developed as materials.

For a conductive paste used to form an electrode, the characteristics of a sintered film obtained by heating the conductive paste are required to be the same as those of a metal film formed by conventional plating. Particularly important are the characteristics related to the bonding of each component; the adhesion of the sintered film composed of various inorganic base materials such as ceramics and ferrites that form the basis of the electrode and the conductive paste, or the use of the electrode for bonding to other components after it is formed. The wettability of solder will affect the adhesion between various components, so it is strictly controlled.

For example, Patent Document 1 discloses a conductive paste that can obtain a sintered film with good adhesion to inorganic substrates such as ceramics and ferrites, and Patent Document 2 discloses a conductive paste that allows the solder of the sintered film to be wetted. Good sex.

[Prior technical literature] [Patent Document] Patent Document 1: Japanese Patent Application Publication No. 2015-86090; Patent Document 2: Japanese Patent Application Publication No. 2006-128005.

[Problem to be solved by the invention] However, although the conductive pastes disclosed in Patent Documents 1 and 2 are excellent in adhesion to the inorganic base material and solder wettability, the conductive paste increases its viscosity over time, resulting in an increase in the thixotropy ratio. , or when temperature unevenness occurs in the heating furnace, the resin component will remain in the sintered film and easily cause the solder wettability to decrease. Therefore, there is a risk that the productivity may be reduced due to inconsistent printing film thickness, or the joint strength may be reduced due to poor wettability of the solder.

The object of the present invention is to provide a conductive composition whose viscosity characteristics are not easily changed during storage and which can form a sintered film with good adhesion to an inorganic substrate and good solder wettability.

[Means used to solve problems] The inventors of the present invention have repeatedly studied in order to solve the above-mentioned problems, and finally found that in addition to the conductive particles and glass frit, an alicyclic alcohol with a carbon number of 7 to 18 is also blended in a specific ratio; thereby, they found a solution to the above-mentioned problems. The conductive composition of the subject was determined, and the present invention was completed.

That is, the present invention relates to a conductive composition, including (a) glass frit, (b) alicyclic alcohol with a carbon number of 7 to 18, (c) conductive particles; wherein, relative to the total, it is 100 mass % The components (a) to (c) contain 0.5 to 20 mass% of component (a), 0.5 to 15 mass% of component (b), and 65 to 99 mass% of component (c).

[Effects of the invention] The viscosity characteristics of the conductive composition of the present invention are not easily changed during storage, and the sintered film of the conductive composition has good adhesion to inorganic substrates such as ceramics or ferrite, and exhibits excellent solder wettability. , so it is suitable for forming electrodes.

Embodiments of the present invention will be described below.

In addition, the numerical range specified by the symbol "~" in this specification includes the numerical values at both ends of "~" (the upper limit and the lower limit); for example, "2 to 5" means 2 or more and 5 or less.

Moreover, when the concentration or amount is limited, any higher concentration or amount can be related to any lower concentration or amount; for example, it is described as "2 to 10 mass %" and "preferably 4 to 8 mass %" When , it also includes “2 to 4 mass %”, “2 to 8 mass %”, “4 to 10 mass %” and “8 to 10 mass %”.

The conductive composition according to the embodiment of the present invention includes (a) glass frit, (b) alicyclic alcohol with a carbon number of 7 to 18, and (c) conductive particles; wherein, relative to a total of 100 mass % of components (a) to (c), it contains 0.5 to 20 mass% of component (a), 0.5 to 15 mass% of component (b), and 65 to 99 mass% of component (c). Each ingredient will be described below.

[Component (a): Glass frit] Component (a) is glass frit. Examples of glass frit components include P ₂ O ₅ (phosphorus oxide), Al ₂ O ₃ (aluminum oxide), Bi ₂ O ₃ (bismuth oxide), B ₂ O ₃ (boron oxide), ZnO (zinc oxide), SiO ₂ (silicon oxide), ZrO ₂ (zirconia), SnO (tin oxide), PbO (lead oxide), alkaline earth metal oxides (for example: BaO (barium oxide), CaO (calcium oxide), SrO (oxide Strontium), etc.), alkali metal oxides (for example: Li ₂ O (lithium oxide), K ₂ O (potassium oxide), Na ₂ O (sodium oxide), etc.), etc.

As the component (a), one selected from these components may be used alone, or two or more types may be used in combination. The content ratio of each component contained in the glass frit is not particularly limited, and any ratio can be used.

Although the average particle diameter (D50) of the glass frit is not particularly limited, in order to print the conductive composition containing component (a) well in various printing methods, it is preferable to control the average particle diameter (D50) of the glass frit. . Specifically, the average particle diameter (D50) of the glass frit is preferably 100 nm to 50 μm, more preferably 1 μm to 30 μm.

In addition, the average particle diameter (D50) of the glass frit can be measured with a laser diffraction and scattering particle size distribution measuring device (microtracMT3000II manufactured by MicrotracBEL Co., Ltd.).

From the viewpoint of improving low-temperature sintering properties, component (a) preferably contains P ₂ O ₅ (phosphorus oxide), Al ₂ O ₃ (aluminum oxide), Bi ₂ O ₃ (bismuth oxide), B ₂ O ₃ ( Boron oxide), ZnO (zinc oxide), SnO (tin oxide), at least one of alkaline earth metal oxides, and alkali metal oxides, and more preferably P ₂ O ₅ (phosphorus oxide).

The content of component (a) is 0.5 to 20 mass%, preferably 1 to 14 mass%, based on a total of 100 mass% of components (a) to (c). If the content of component (a) is too small, the adhesion between the sintered film obtained from the conductive composition and the inorganic substrate will be reduced. On the other hand, if the content of component (a) is too high, the adhesiveness between the conductive composition and the inorganic substrate will be reduced. The electrical conductivity of the sintered film obtained.

[Ingredient (b): Alicyclic alcohol] Component (b) is an alicyclic alcohol having 7 to 18 carbon atoms. Examples of the alicyclic alcohol include 1-adamantanol (number of carbon atoms: 10, number of rings: 3), 2-adamantanol (number of carbon atoms: 10, number of rings: 3), and 1,3-adamantanediol. (carbon number: 10, ring number: 3), iso-cyclohexanol (carbon number: 16, ring number: 3), 4-iso-𦯉-2-methylcyclohexan-1-ol (carbon number: : 17, ring number: 3), 𦯉 alcohol (carbon number: 10, ring number: 2), iso-𦯉 alcohol (carbon number: 10, ring number: 2), nor 𦯉 alcohol (carbon number: 7, ring number: 2), 1,3,3-trimethyl-2-norbiol (carbon number: 10, ring number: 2), tricyclodecane dimethanol (carbon number: 12, ring number: 3), tricyclic Decane diethanol (carbon number: 14, ring number: 3), tricyclodecane dipropanol (carbon number: 16, ring number: 3), tricyclodecane dibutanol (carbon number: 18, ring number :3), tetracyclodecan-2-ol (carbon number: 12, ring number: 4), etc.

As component (b), one selected from these components may be used alone, or two or more types may be used in combination. When two or more types are used in combination, the content ratio of each component is not particularly limited, and any ratio can be used.

Component (b) preferably has 8 to 18 carbon atoms, more preferably 12 to 16 carbon atoms. Moreover, the number of rings of the alicyclic alcohol contained in component (b) is preferably 2 to 4, more preferably 2 to 3.

From the viewpoint of the number of carbon atoms and the number of rings of the alicyclic alcohol, it is preferable to use a compound selected from iso-cyclohexanol and tricyclodecane dimethanol, and iso-cyclohexanol is more preferred.

The content of component (b) is 0.5 to 15 mass%, preferably 2 to 10 mass%, based on a total of 100 mass% of components (a) to (c). If the content of component (b) is too small, the thixotropy ratio will easily increase during storage. On the other hand, if the content of component (b) is too high, the conductivity of the conductive composition will be reduced.

[Component (c): Conductive particles] Component (c) is conductive particles, and for example, inorganic conductive particles such as copper particles can be used. The copper particles may be composed solely of copper, but may further contain metals other than copper such as silver or platinum, metal oxides, and metal sulfides. When the copper particles further contain metals other than copper, metal oxides, and metal sulfides, the mass ratio of copper in the copper particles is preferably 50 mass % or more. Furthermore, the copper particles may have a shape in which a surface layer or protrusions are formed.

Commercially available products can be used as conductive particles as they are, but when the purpose is to improve oxidation resistance or the like, it is preferable to use surface-coated conductive particles that cover the surface. Among them, surface-coated conductive particles whose surface is coated with an amine compound are preferred, and surface-coated conductive particles whose surface is coated with an amine compound represented by the following formula (1) are more preferred.

Furthermore, one type of surface-coated conductive particles may be used alone, or surface-coated conductive particles and commercially available conductive particles may be used in combination. …Formula 1)

(In formula (1), m is an integer from 0 to 3, n is an integer from 0 to 2, when n=0, m is any one from 0 to 3; when n=1 or n=2, m is Any one from 1 to 3.)

From the viewpoint of obtaining better oxidation resistance, the surface-coated conductive particles represented by formula (1) whose surface is coated with an amine compound such as an amine compound are preferably further coated with an aliphatic monocarboxylic acid. The surface is covered with conductive particles.

Thereby, the surface of the conductive particle is covered with the first coating layer formed of the amine compound and the second coating layer formed of the aliphatic monocarboxylic acid. Preferably, the first coating layer is formed on the surface of the conductive particles, and the second coating layer is formed on the first coating layer.

The aliphatic monocarboxylic acid forming the second coating layer is preferably an aliphatic monocarboxylic acid having 8 to 24 carbon atoms. The aliphatic monocarboxylic acid is, for example, a linear saturated aliphatic monocarboxylic acid, a linear unsaturated aliphatic monocarboxylic acid, a branched saturated aliphatic monocarboxylic acid, or a branched unsaturated aliphatic monocarboxylic acid.

Examples of linear saturated aliphatic monocarboxylic acids having 8 to 24 carbon atoms include caprylic acid, nonanoic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, and heptadecanoic acid. , stearic acid, nonadecanic acid, arachidic acid, etc. Examples of linear unsaturated aliphatic monocarboxylic acids having 8 to 24 carbon atoms include myristic acid, palmitoleic acid, acelinic acid, and oleic acid. Examples of branched saturated aliphatic monocarboxylic acids having 8 to 24 carbon atoms include 2-ethylhexanoic acid.

As the aliphatic monocarboxylic acid, one selected from the above compounds may be used alone, or two or more types may be used in combination.

The method of manufacturing the surface-coated conductive particles is not particularly limited. A method for obtaining surface-coated conductive particles whose surface is coated with an amine compound is, for example, by washing the conductive particles with, for example, an aqueous ammonium chloride solution, and then adding the washed conductive particles to a solution of the amine compound. A method of heating the solution as necessary; and a method of adding conductive particles to a solution containing ammonium chloride and an amine compound and heating the solution as necessary.

The surface-coated conductive particles are coated with a first coating layer formed of an amine compound and a second coating layer formed of an aliphatic monocarboxylic acid. The manufacturing method may be, for example, coating the conductive particles with an amine compound. The surface-coated conductive particles are washed with a cleaning solvent such as alcohol if necessary, and then added to a solution of aliphatic monocarboxylic acid. Alternatively, after being added to a solution of aliphatic monocarboxylic acid, the particles are heated if necessary.

Although the average particle diameter (D50) of the conductive particles is not particularly limited, in order to favorably print the conductive composition containing the conductive particles of component (c) in various printing methods such as screen printing, it is preferably controlled to Average particle size (D50) of conductive particles. Specifically, the average particle diameter (D50) of the conductive particles is preferably 5 nm to 20 μm, more preferably 10 nm to 10 μm.

In addition, the average particle diameter (D50) of the conductive particles can be measured with a laser diffraction scattering particle size distribution measuring device (microtracMT3000II manufactured by MicrotracBEL Co., Ltd.).

Furthermore, the BET specific surface area of the conductive particles is preferably 0.05 to 400 m ² /g, more preferably 0.1 to 200 m ² /g.

In addition, the BET specific surface area of the conductive particles can be measured by the BET single-point method using a specific surface area measuring device (Monosobe manufactured by Yuasa-Ionics Co., Ltd.).

The shape or aspect ratio (the ratio of the long diameter to the short diameter of the particles) of the conductive particles is not particularly limited, and spherical, polyhedral, flat, plate, flake, flake, rod, and dendritic shapes can be used. , fibrous and other various shapes. As the conductive particles, one selected from those having different constituent components, average particle diameter, BET specific surface area, shape, aspect ratio, etc. may be used alone, or two or more types may be used in combination. When two or more types are used in combination, the content ratio of each component is not particularly limited and can be appropriately determined taking into account the characteristics of each component.

The content of component (c) is 65 to 99 mass % with respect to a total of 100 mass % of components (a) to (c). The lower limit of the content of component (c) is preferably 70% by mass, more preferably 75% by mass.

〔Other ingredients〕 In addition to the above-mentioned components (a) to (c), the conductive composition may contain solvents, conductivity enhancers, antioxidants, lubricants, leveling agents, and dispersants as needed within the scope that does not hinder the effects of the present invention. , hardener, hardening accelerator, viscosity adjuster, foaming agent, defoaming agent and other additives. The method and timing of adding these various additives to the conductive composition are not particularly limited and can be appropriately determined taking into account the characteristics of each component. In addition, the conductive composition may contain raw material components and impurities inevitably mixed from equipment in the manufacturing process. Furthermore, when any of these components is contained, the total content may be more than 0 parts by mass and 60 parts by mass or less, preferably 30 parts by mass or less, based on 100 parts by mass of the total content of (a) to (c).

(solvent) The conductive composition may contain a solvent for the purpose of improving kneading workability during production, improving coating properties, and adjusting viscosity.

The type of solvent is not particularly limited, and various solvents can be used depending on the application. Examples include ethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, and ethylene glycol monoethyl ether. Ether alcohols such as alcohol monobutyl ether acetate; non-ether alcohols such as propylene glycol and 1,4-butanediol; cyclohexanol acetate, methylmethoxypropionate, ethyl ethoxy Esters such as propionate, 1,6-hexanediol acetate, propylene carbonate; ketones such as isophorone, cyclohexanone; terpineol, dihydroterpineol, dihydroterpine Terpenes such as ethyl acetate; other hydrocarbons such as octane, decane, dodecane, tetradecane, hexadecane, etc., but are not limited to these. One type of solvent may be used alone, or two or more types may be mixed. When two or more types are mixed, the mixing ratio is not particularly limited.

The type of solvent is preferably one or more selected from the above-mentioned ether alcohols, the above-mentioned esters, and the above-mentioned terpenes, and more preferably one or more selected from the above-mentioned ether alcohols and terpenes. Two or more types are used, and it is particularly preferred to use one or two or more types selected from terpenes. The mixing ratio when mixing two or more of these solvents is not particularly limited.

When the conductive composition contains a solvent, the content of the solvent is preferably 1 to 20 parts by mass, more preferably 2 to 15 parts by mass relative to 100 parts by mass of the components (a) to (c) in total.

(Conductivity improving agent) When the purpose is to improve the conductivity of the sintered film obtained by heating, the conductive composition may contain a conductivity improving agent. The type of conductivity improving agent is not particularly limited, and various conductivity improving agents can be used depending on the application. For example, vinyl trimethoxysilane (brand name: KBM-1003, manufactured by Shin-Etsu Chemical Industry Co., Ltd.), 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (brand name: KBM-303, Shin-Etsu Chemical Industry Co., Ltd.) Chemical Industry Co., Ltd.), 3-glycidoxypropyltrimethoxysilane (product name: KBM-403, Shin-Etsu Chemical Industry Co., Ltd.), N-2-(aminoethyl)-3- Aminopropyltrimethoxysilane (brand name: KBM-603, manufactured by Shin-Etsu Chemical Industry Co., Ltd.), 3-aminopropyltrimethoxysilane (brand name: KBM-903, manufactured by Shin-Etsu Chemical Industry Co., Ltd.), N-phenyl-3-aminopropyltrimethoxysilane (brand name: KBM-573, manufactured by Shin-Etsu Chemical Industry Co., Ltd.), 3-mercaptopropyltrimethoxysilane (brand name: KBM-803, Shin-Etsu Chemical Industry Co., Ltd.) Co., Ltd.) and other silane alkoxide compounds, isopropyl triisostearyl titanate (brand name: PLENACT TTS, manufactured by Ajinomoto Fine-Techno Co., Ltd.), isopropyl tris(dodecyl) Benzenesulfonyl titanate (brand name: PLENACT 9S, manufactured by Ajinomoto Fine-Techno Co., Ltd.), isopropyl tris(dioctylpyrophosphate) titanate (brand name: PLENACT 38S, manufactured by Ajinomoto Fine-Techno Co., Ltd. company), tetraisopropylbis(dioctylphosphite) titanate (product name: PLENACT 41B, manufactured by Ajinomoto Fine-Techno Co., Ltd.), tetraoctylbis(di(tridecyl)phosphite) Ester) titanate (product name: PLENACT 46B, manufactured by Ajinomoto Fine-Techno Co., Ltd.), tetrakis(2,2-diallyloxymethyl-1-butyl)bis(di(tridecyl)) Phosphite titanate (brand name: PLENACT 55, manufactured by Ajinomoto Fine-Techno Co., Ltd.), isopropyl tris(N-amideethylaminoethyl) titanate (brand name: PLENACT 44, Ajinomoto Fine- Techno Co., Ltd.) and other titanium alkoxide compounds, but are not limited to these. The conductivity improving agent may be used alone or in a mixture of two or more types; the mixing ratio when two or more types are mixed is not particularly limited.

The type of conductivity improving agent is preferably one or more selected from the above-mentioned titanium alkoxide compounds, and more preferably, one selected from a titanium alkoxy compound having an alkoxy group having 2 to 8 carbon atoms is used. One or more than two types. The mixing ratio when mixing two or more types of conductivity improving agents is not particularly limited.

When the conductive composition contains a conductivity enhancing agent, the content of the conductivity enhancing agent is preferably 0.5 to 15 parts by mass, more preferably 1 to 15 parts by mass, based on a total of 100 mass % of the components (a) to (c). 10 parts by mass.

(Antioxidant) For the purpose of maintaining the performance of each produced component during storage, the conductive composition may contain an antioxidant. The type of antioxidant is not particularly limited, and various antioxidants can be used depending on the purpose. Examples include nitrogen-containing heterocyclic compounds such as 2,2-bipyridine and 1,10-phenanthroline, N,N'-bis(salosylene)ethylenediamine, and N,N'-bis(salphenyl) -1,2-propanediamine, N,N'-bis(salphenyl)-1,3-propanediamine, N,N'-bis(salphenyl)-1,2-phenylenediamine, etc. Phosphorus bases, 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine, 2,3,5, 6-Tetramethyl-1,4-phenylenediamine, N,N-dimethyl-1,4-phenylenediamine, N,N,N'N'-tetramethyl-1,4-phenylenediamine, Aromatic diamines such as N,N'-diphenyl-1,4-phenylenediamine, p-methoxyphenol, hydroquinone, tert-butylhydroquinone, dibutylhydroxytoluene, catechol, 4-tert-butylcatechol, pyrogallol, eugenol, propyl gallate and other phenols, L-ascorbic acid, 6-O-palmitoyl-L-ascorbic acid, 6-O-hard Ascorbic acids such as fatty acid-L-ascorbic acid and tetrakis-2-hexyldecanoic acid ascorbic acid ester are not limited thereto. One type of antioxidant may be used alone or two or more types may be mixed. When two or more types are mixed, the mixing ratio is not particularly limited.

As the type of antioxidant, it is preferable to use 2,2-bipyridyl from the above-mentioned nitrogen-containing heterocyclic compounds, N,N'-bis(salosylidene)ethylenediamine, N,N from the above-mentioned Schiff bases. '-Bis(salgylene)-1,2-propanediamine, 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenylenediamine, the above-mentioned aromatic diamines, and the above-mentioned phenol Selected from the likes of p-methoxyphenol, hydroquinone, tert-butylhydroquinone, and the above-mentioned ascorbic acids such as 6-O-palmitoyl-L-ascorbic acid and 6-O-stearyl-L-ascorbic acid One or more than two kinds of these antioxidants; the mixing ratio when mixing two or more kinds of these antioxidants is not particularly limited.

When the conductive composition contains an antioxidant, the content of the antioxidant is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on a total of 100 mass % of the components (a) to (c).

(lubricant) For the purpose of adjusting the dispersibility of the conductive particles of component (c) in the conductive composition, a lubricant may be appropriately added to the conductive composition. The type of lubricant and its mixing ratio are not particularly limited, and one type can be used alone or two or more types can be mixed according to the purpose.

Examples of lubricants include fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid; sodium, potassium, barium, magnesium, calcium, aluminum, iron, cobalt, manganese, zinc, tin Fatty acid metal salts such as metals that form salts with the aforementioned fatty acids; fatty acid amide such as stearic acid amide, oleic acid amide, behenic acid amide, palmitic acid amide, lauric acid amide and other fatty acid amide; stearic acid Fatty acid esters such as butyl ester; waxes such as paraffin wax and flowing paraffin; alcohols such as ethylene glycol and stearyl alcohol; polysiloxanes such as polysiloxane oil; fluorine compounds such as fluorine-based oils, but not limited to Wait.

The type of lubricant is preferably one or more selected from fatty acids and fatty acid metal salts, and more preferably is used from lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid and One or more selected from magnesium stearate, zinc stearate and calcium stearate.

When the conductive composition contains a lubricant, the content of the lubricant is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on a total of 100 mass % of components (a) to (c).

(dispersant) For the purpose of adjusting the dispersibility of the conductive particles of component (c) in the conductive composition, a dispersant may be appropriately added to the conductive composition. The type of dispersant and its mixing ratio are not particularly limited, and one type may be used alone or two or more types may be mixed depending on the application.

Examples of dispersants include sarcosine compounds such as lauryl sarcosine, myristyl sarcosine, palmityl sarcosine, stearyl sarcosine, and oleyl sarcosine; FILLANOL PA-075F, FILLANOL PA-085C, FILLANOL PA-107P, ESLEAM AD-3172M, ESLEAM AD-374M, ESLEAM AD-508E, (the above are manufactured by NOF Co., Ltd.) and other polymer amine compounds; MALIALIM AKM -0531, MALIALIM AFB-1521, MALIALIM AAB-0851, MALIALIM AWS-0851, MALIALIM SC-0505K, MALIALIM SC-1015F, MALIALIM SC-0708A (the above are manufactured by NOF Co., Ltd.) and other polymer polycarboxylic acid compounds categories, but are not limited to such categories.

As the type of dispersing agent, it is preferable to use one or two or more types selected from sarcosines, and more preferably to use one or two or more types selected from lauryl sarcosine and oleyl sarcosine.

When the conductive composition contains a dispersant, the content of the dispersant is preferably 0.1 to 10 parts by mass, more preferably 0.2 to 5 parts by mass relative to 100 mass % of the components (a) to (c) in total.

The above-mentioned conductive composition can be obtained by mixing and kneading the above-mentioned components in a fixed method. Alternatively, a conductive composition may be used, a coating film may be formed by a fixing method, and then the coating film may be heated to obtain a sintered film (metal film). The viscosity characteristics of the conductive composition are not easily changed during storage, and the sintered film, such as a coating film formed by screen printing or other printing (for example, for forming electrodes or wiring patterns, etc.) is not prone to film thickness inconsistency after sintering; for example Good adhesion to inorganic substrates and excellent solder wettability. Therefore, for example, the conductive composition is suitable as the polarity-forming material.

(Example) Examples and comparative examples are listed below to further describe the embodiments of the present invention in detail.

Each component used in the Examples and Comparative Examples is as follows. In addition, the physical properties of each component are values measured by the method described in this specification.

[Component (a): glass frit] ･P ₂ O ₅ -Al ₂ O ₃ -R ₂ O (product name: VY0144, R is an alkali metal atom, manufactured by TAKARA STANDARD Co., Ltd.). ･P ₂ O ₅ -ZnO-RO (product name: CY0046, R is an alkaline earth metal atom, manufactured by TAKARA STANDARD Co., Ltd.). ･B ₂ O ₃ -Al ₂ O ₃ -ZnO (product name: CY0113, manufactured by TAKARA STANDARD Co., Ltd.). ･B ₂ O ₃ -Bi ₂ O ₃ (product name: ASF-1096, manufactured by AGC Co., Ltd.). ･SnO-P ₂ O ₅ (product name: KP312, manufactured by AGC Co., Ltd.). ･B ₂ O ₃ -ZnO-RO (product name: EY0072, R is an alkaline earth metal atom, manufactured by TAKARA STANDARD Co., Ltd.).

[Ingredient (b): Alicyclic alcohol] (b1): Isocyclohexanol (product name: Tersolve MTPH, manufactured by NIPPON TERPENE Co., Ltd., carbon number: 16, ring number: 3). (b2): Tricyclodecane dimethanol (product name: TCDDM, manufactured by Oxea, carbon number: 12, ring number: 3).

[Ingredients (b’): Cellulose derivatives] ･Ethylcellulose.

[Component (c): Conductive particles] ･Copper particles (1): spherical copper particles [surface-coated copper particles (1), the production method is shown in Synthesis Example 1 below]. ･Copper particles (2): Plate-shaped copper particles [surface-coated with copper particles (2), production method shown in Synthesis Example 2 below]. ･Copper particles (3): Spherical copper particles [1200Y, Mitsui Metal Mining Co., Ltd., particle size (D50): 2 μm, BET specific surface area: 0.40 m ² /g, shape: spherical].

〔Other ingredients〕

(Conductivity improving agent) ･Tetraoctylbis(di(tridecyl)phosphite) titanate (product name: PLENACT 46B, manufactured by Ajinomoto Fine-Techno Co., Ltd.). ･Tetraisopropyl bis(dioctyl phosphite) titanate (product name: PLENACT 41B, manufactured by Ajinomoto Fine-Techno Co., Ltd.).

(solvent) ･Terpineol.

[Synthesis Example 1] (Production of Copper Particles (1): Surface-Coated Copper Particles (1)) An ammonium chloride aqueous solution in which 5 g of ammonium chloride was dissolved in 100 g of water was prepared. Add 50 g of copper particles a ["1200Y" manufactured by Mitsui Mining & Metals Co., Ltd.; particle size (D50) 2 μm, BET specific surface area 0.40 m ² /g, shape: spherical] to an aqueous ammonium chloride solution, and bubble it under nitrogen Stir at 30°C for 60 minutes. Stirring was performed using a mechanical stirrer at a rotation speed of 150 rpm. The following stirrings were performed using the same stirring device and at the same rotational speed. After stirring, use a Kiriyama funnel with 5C filter paper to filter the copper particles under reduced pressure, and then wash the copper particles twice with 150 g of water on the Kiriyama funnel.

The washed copper particles were added to 250 g of a 40% by mass diethylenetriamine aqueous solution, and the mixture was heated and stirred at 60° C. for 1 hour while bubbling nitrogen.

Stop stirring and let it stand for 5 minutes, then take out about 200g of the supernatant and remove it. Next, 200 g of isopropyl alcohol as a cleaning solvent was added to the sediment, and the mixture was stirred at 30° C. for 3 minutes. After stopping the stirring and letting it stand for 5 minutes, about 200 g of the supernatant was taken out and removed. Thereafter, 250 g of a 2 mass% lauric acid isopropyl alcohol solution was added, and the mixture was stirred at 30° C. for 30 minutes.

After stirring, use 5C filter paper and Kiriyama funnel to filter under reduced pressure to filter the copper particles. The obtained copper particles were dried under reduced pressure at 25° C. for 3 hours, thereby obtaining surface-coated copper particles (1) (copper particles (1)).

[Synthesis Example 2] (Copper Particles (2): Production of Surface-Coated Copper Particles (2)) Copper particles a were changed to copper particles b ["1400YP" manufactured by Mitsui Mining & Metals Co., Ltd.; particle size (D50) 6 μm, BET specific surface area 0.60 m ² /g, shape: plate], except that the surface-coated copper particles (2) (copper particles (2)) were obtained in the same manner as in Synthesis Example 1.

[Example 1] (Production of conductive composition) 10.0 g of P ₂ O ₅ -Al ₂ O ₃ -R ₂ O as component (a) and 5.0 g of isocyclohexanol as component (b) were mixed. , and 85 g of surface-coated copper particles (copper particles (1)) of component (c). Next, a planetary mixer [ARV-310, manufactured by THINKY Co., Ltd.] was used to stir the mixture at 2000 rpm for 60 seconds at room temperature to perform the first kneading.

Next, a 3-roller mill [EXAKT-M80S, manufactured by Nagase Screen Printing Research Co., Ltd.] was used to pass 5 times at room temperature and with a distance between rollers of 5 μm, thereby performing the second kneading. 5.0 g of terpineol (Ter) was added to the kneaded product obtained by the second kneading, and a planetary mixer was used to stir at 2000 rpm for 60 seconds under room temperature and vacuum conditions, and then degassed and kneaded to produce a conductive composition. Various evaluations described below were performed using the obtained conductive composition. Table 1 shows the blending ratio of each component of the conductive composition.

[Examples 2 to 14, Comparative Examples 1 to 3] Except for the blending ratio of each component as shown in Table 1, a conductive composition was produced in the same manner as in Example 1, and various evaluations described below were performed.

[Evaluation] ＜Conductivity evaluation＞ (Formation of sintered film) Using a metal mask with width × length × thickness = 1 mm × 30 mm × 50 μm, the conductive compositions obtained in each example and comparative example were coated on a 50 mm × 50 mm glass substrate. Using an inert gas oven, the glass substrate coated with the conductive composition was heated at 500° C. for 60 minutes in a nitrogen environment to produce a sintered film.

(Evaluation method of resistance value) The electrical conductivity of the sintered film obtained by the above method was evaluated by the following resistance value measurement. Measurement probes were crimped onto both ends of the formed pattern, and the resistance value of the sintered film was measured using a digital multimeter [PC7000, manufactured by Sanwa Electric Instruments Co., Ltd.] and judged based on the following evaluation criteria. In this test, the lower the resistance value of the sintered film, the easier it is for electric current to flow, indicating excellent electrical conductivity. ◎: The resistance value is less than 1.0Ω. ○: The resistance value is 1.0Ω or more and less than 10.0Ω. △: The resistance value is 10.0Ω or more and less than 50.0Ω. ×: The resistance value is 50.0Ω or more.

＜Evaluation of viscosity characteristics＞ (Evaluation method of thixotropy) The conductive composition obtained in each example and comparative example was measured under specific conditions using an E-type viscometer [TVE-25H, set temperature: 25°C, conical rotor: 3° × R7.7, manufactured by Toki Industrial Co., Ltd.] The viscosity of the product at the initial stage (after manufacturing) and after storage at 5°C for 30 days is used to calculate the thixotropy ratio using the following mathematical formula (1).

[Number 1] thixotropy = Viscosity measurement value at 0.5 rpm (Pa・ｓs) …(1) Viscosity measurement value at 5.0 rpm (Pa・ｓs)

Next, the rate of change of the thixotropy ratio (thixotropy ratio change rate) is calculated using the following mathematical formula (2).

[Number 2] Thixotropy change rate (%) = Thixotropy ratio after storage at 5°C for 30 days × 100 …(2) Initial thixotropy

In this test, the closer the value of the thixotropy change rate is to 100%, the less likely it is for the viscosity of the conductive composition to change during continuous printing, indicating that the printed wiring pattern can be stabilized. The evaluation criteria are as follows. ◎: The thixotropy change rate is less than 120%. ○: The thixotropy change rate is more than 120% and less than 150%. △: The thixotropy change rate is more than 150% and less than 200%. ×: The thixotropy change rate is more than 200%.

＜Evaluation method of solder wettability＞ The conductive compositions obtained in each example and comparative example were coated on a 10 mm × 10 mm alumina substrate using a metal mask with width × length × thickness = 5 mm × 5 mm × 50 μm. Using an inert gas oven, the alumina substrate coated with the conductive composition was heated at 500° C. for 60 minutes in a nitrogen environment to produce a sintered film.

Next, solder paste (product name: TLF-204-171A, solder composition: Sn-3.0Ag) is applied to the center of the surface of the sintered film formed on the alumina substrate using a metal mask with width × length × thickness = 2 mm × 2 mm × 200 μm. -0.5Cu, TAMURA Corporation). The alumina substrate with the sintered film coated with the solder paste was heated at 280° C. for 3 minutes in a nitrogen environment to melt the solder paste on the surface of the sintered film, and then allowed to cool to room temperature.

Then, a contact angle meter (product name: DMs-401, Kyowa Interface Science Co., Ltd.) was used to measure the contact angle on the surface of the heat-treated solder paste (solder alloy).

In this test, the smaller the measured value of the contact angle is, the better the solder wettability of the sintered film obtained using the conductive composition is. The evaluation criteria are as follows. ◎: The contact angle is less than 20°. ○: The contact angle is 20° or more and less than 40°. △: The contact angle is 40° or more and less than 60°. ×: The contact angle is 60° or more.

＜Evaluation method of adhesion strength＞ The conductive compositions obtained in each Example and Comparative Example were coated on the central portion of the surface of a 5 mm × 5 mm base material (alumina substrate) using a metal mask of width × length × thickness = 2 mm × 2 mm × 50 μm. Using an inert gas oven, the alumina substrate coated with the conductive composition was heated at 500°C for 60 minutes in a nitrogen environment to produce a sintered film.

Next, use a metal mask with width × length × thickness = 2mm × 2mm × 200μm to apply solder paste (product name: TLF-204-171A, solder composition: Sn-3.0Ag-0.5) on the surface of the sintered film formed on the alumina substrate. Cu, TAMURA Corporation Co., Ltd.). The alumina substrate with a sintered film coated with solder paste was heated at 280° C. for 3 minutes in a nitrogen environment, thereby melting the solder paste on the surface of the sintered film to form a solder alloy, and then allowed to cool to room temperature.

Next, apply flux (product name: FS-200, manufactured by White Light Co., Ltd.) on one side of a double-sided copper foil laminate with width × length × thickness = 10 mm × 10 mm × 3 mm, and combine the alumina substrate/sintered film/solder alloy The solder alloy surface of the constructed laminated parts is fixed to the flux-coated surfaces of the copper foil laminated boards on both sides.

With the laminated parts composed of the alumina substrate/sintered film/solder alloy fixed to the flux-coated surfaces of both sides of the copper foil laminated board, the solder alloy is remelted by heating at 280°C for 3 minutes in a nitrogen environment. A test piece for measuring the adhesion strength of a laminated component composed of a double-sided copper foil laminated board and an alumina substrate/sintered film/solder alloy was obtained.

Next, a screw stake (aluminum diameter 2.7mm, length 12.7mm, manufactured by Quad Group) with epoxy adhesive attached was fixed to the center of the alumina substrate surface of the test piece for adhesion strength measurement, and the temperature was maintained at 150°C in a nitrogen atmosphere. Heating was performed for 60 minutes to install screw piles on the alumina substrate surface.

Next, a vertical tensile test (test temperature: 23°C, test speed: 1 mm/min) was performed using an Autograph (product name: AG-X, manufactured by Shimadzu Corporation), and the adhesion strength between the alumina substrate and the sintered film was measured.

In this test, the larger the measured value of the adhesion strength is, the better the adhesion between the sintered film obtained using the conductive composition and the alumina substrate is. The evaluation criteria are as follows. ◎: Adhesion strength is 30N or more. ○: Adhesion strength is 15N or more and less than 30N. △: Adhesion strength is 5N or more and less than 15N. ×: The adhesion strength is less than 5N.

The above evaluation results are shown in Table 2.

[Table 1]

[Table 2]

The following matters can be seen from Table 2.

In Examples 1 to 14, the resistance value of the sintered film did not reach 10.0Ω, the thixotropy ratio change rate of the conductive composition when stored at 5°C for 30 days did not reach 150%, and the solder contact after the solder wettability test The angle is less than 40°, and the adhesion strength between the sintered film obtained using the conductive composition and the alumina substrate is 15N or more.

In contrast, in Comparative Example 1, in which the conductive composition was prepared without blending component (a), the adhesion strength was less than 5N, which is a relatively low value. In addition, in Comparative Example 1, in which component (b) was not blended and the conductivity was prepared. In Comparative Example 2 of the composition, the thixotropy ratio change rate is more than 150%, which is a relatively high value; and in Comparative Example 3 of preparing a conductive composition using ethylcellulose as the substitute component (b), the thixotropy ratio The specific change rate is more than 200%, which is a relatively high value, and the contact angle is more than 40°, which is a relatively high value.

As described above, it is expected that a conductive composition containing specific components (a) to (c) in a specific ratio will have a small change in thixotropy ratio during storage, thereby enabling stable printing, and furthermore, it is expected that burning caused by printing will be less likely to occur. The film thickness of the conjunctiva is inconsistent; in addition, a sintered film exhibiting excellent conductivity and solder wettability can be obtained, and the obtained sintered film has excellent adhesion strength to inorganic substrates such as alumina. From the above, it can be seen that the above-mentioned specific conductive composition is suitable as an electrode-forming material.

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Claims (1)

A conductive composition including: (a) glass material; (b) Alicyclic alcohols with 7 to 18 carbon atoms; and (c) Conductive particles; Among them, 0.5 to 20 mass % of component (a), 0.5 to 15 mass % of component (b), and 65 to 99 mass % of component ( c).