JP5320974B2 - Conductive composition, substrate with conductive film, and method for producing the same - Google Patents

Description

  The present invention relates to a conductive composition, a substrate with a conductive coating, and a method for producing the same.

  Conventionally, a binder made of a synthetic resin substrate such as a polyester film, conductive particles such as silver particles, thermoplastic resin such as acrylic resin or vinyl acetate resin, thermosetting resin such as epoxy resin or unsaturated polyester resin, etc. A conductive composition such as a silver paste obtained by adding an organic solvent, a curing agent, a catalyst, etc. and mixing them is printed by a printing method such as screen printing so that a predetermined circuit pattern is obtained, and these are heated. A method of manufacturing a circuit board by forming a conductive film forming a conductor circuit is known.

  For example, Patent Document 1 describes “a silver compound paste characterized by containing particulate silver oxide and a tertiary fatty acid silver salt.”

  Patent Document 2 discloses a conductive composition containing “silver oxide (A) and a secondary fatty acid silver salt (C) obtained using a secondary fatty acid having a boiling point of 200 ° C. or lower” by the present applicant. Is proposed. "

  In addition, Patent Document 3 discloses that the present applicant has described "silver oxide, secondary fatty acid silver salt having 7 or less carbon atoms, linear or branched fatty acid and / or carbon having 8 or more carbon atoms". A conductive composition containing a linear or branched fatty acid silver salt having 8 or more atoms and a solvent has been proposed.

JP 2003-203522 A Japanese Patent No. 3990712 Japanese Patent No. 4050301

However, although the silver compound paste described in Patent Document 1 is a low-temperature firing type, a heat treatment at a temperature of 180 ° C. or higher for 30 minutes or longer is required for forming a conductive film.
For this reason, it has been difficult to form a conductive film on a substrate having low heat resistance (for example, polyethylene terephthalate (PET) film). Moreover, since the heat processing for a long time is required, there existed a problem that productivity of a conductive film was low.

  On the other hand, the conductive compositions described in Patent Document 2 and Patent Document 3 can form a conductive film satisfactorily on a substrate having a short conductive film formation time and low heat resistance. As a result of further improvement of the conductive composition, the inventors have clarified that there is room for forming a conductive film having a small specific resistance at a lower temperature and in a shorter time.

  Therefore, the present invention provides a conductive composition capable of forming a conductive film having a low specific resistance at a low temperature and in a short time, and capable of forming a conductive film satisfactorily even on a substrate having low heat resistance. It is an object of the present invention to provide a base material having a conductive film using a conductive composition and a method for producing the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a conductive composition containing silver oxide and a fatty acid silver salt having one or more amino groups has a low specific resistance at a low temperature in a short time. It was found that a conductive film can be formed, and a conductive film can be satisfactorily formed on a substrate having low heat resistance, and the present invention has been completed.

That is, the present invention provides the following (i) to ( vi ).
(I) a silver oxide (A) and a fatty acid silver salt (B) having at least one amino group, and the fatty acid silver salt (B) is oxidized with a fatty acid B ′ having at least one amino group A conductive composition which is obtained by reacting with silver, and wherein the fatty acid B ′ is a compound represented by any one of formulas (1) to (3) described later .
(Ii) The conductive composition according to (i), wherein the content of the fatty acid silver salt (B) is 0.1 to 50 parts by mass with respect to 100 parts by mass of the silver oxide (A).
(Iii) A secondary fatty acid obtained by using a fatty acid silver salt (C) having at least one hydroxyl group and having no amino group, and / or a secondary fatty acid having a boiling point of 200 ° C. or less and having no amino group. A silver salt (D), wherein the fatty acid silver salt (C) is 2,2-bis (hydroxymethyl) -n-butyric acid silver salt, 2,2-bis (hydroxymethyl) propionic acid silver salt, and The conductive composition according to the above (i) or (ii), which is at least one selected from the group consisting of silver hydroxypivalate .
(Iv ) The conductive composition according to (iii ), wherein the secondary fatty acid silver salt (D) is a 2-methylpropanoic acid silver salt.
( V ) A coating film forming step in which the conductive composition according to any one of (i) to ( iv ) above is applied onto a substrate to form a coating film; The heat processing process of obtaining a conductive film, The manufacturing method of the base material with a conductive film which comprises.
( Vi ) The manufacturing method of the base material with a conductive film as described in said ( v ) whose said heat processing is a process heated to the temperature of 100-250 degreeC .

As shown below, according to the present invention, a conductive film having a small specific resistance can be formed at a low temperature in a short time, and a conductive film can be formed well even on a substrate having low heat resistance. An electrically conductive composition, a substrate with the electrically conductive composition, and a method for producing the same can be provided.
Use of the conductive composition of the present invention is very useful because a circuit such as an electronic circuit and an antenna can be easily and quickly produced on a substrate having low heat resistance.

The conductive composition of the present invention is a conductive composition containing silver oxide (A) and a fatty acid silver salt (B) having one or more amino groups.
Below, silver oxide (A) and fatty acid silver salt (B) are explained in full detail.

<Silver oxide (A)>
The silver oxide (A) used in the conductive composition of the present invention is silver (I), that is, Ag ₂ O.
In the present invention, the shape of the silver oxide (A) is not particularly limited, but is preferably in the form of particles having a particle diameter of 10 μm or less, and more preferably 1 μm or less. When the particle diameter is within this range, a self-reduction reaction occurs at a lower temperature, and as a result, a conductive film can be formed at a lower temperature.

<Fatty acid silver salt (B)>
The fatty acid silver salt (B) used in the conductive composition of the present invention is a fatty acid silver salt having one or more amino groups, preferably two or more, and specifically, one or more amino groups shown below. It is obtained by reacting a fatty acid (hereinafter also referred to as “fatty acid B ′”) with silver oxide.

  The fatty acid B ′ used in the above reaction is not particularly limited as long as it is a fatty acid having 1 or more, preferably 2 or more amino groups, and examples thereof include compounds represented by the following formulas (1) to (3). It is done.

In formula (1), n represents an integer of 0 to 2, R ¹ represents a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 10 carbon atoms which may have a hydroxyl group, and R ² represents 1 to 6 carbon atoms. Represents an alkylene group. When n is 0 or 1, the plurality of R ² may be the same or different from each other. When n is 2, the plurality of R ¹ may be the same or different.
In Formula (2), R ¹ represents a hydrogen atom, a hydroxyl group, or an alkyl group having 1 to 10 carbon atoms which may have a hydroxyl group, and a plurality of R ¹ may be the same or different.
In Formula (3), R ¹ represents a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 10 carbon atoms which may have a hydroxyl group, and R ³ represents an alkylene group having 1 to 6 carbon atoms. The plurality of R ¹ may be the same or different.

In the above formula (1) to (3), the alkyl group having 1 to 10 carbon atoms of R ^1, a methyl group, an ethyl group, n- propyl group, n- butyl group, n- pentyl group, n- hexyl group , N-heptyl group, n-octyl group, n-nonyl group and n-decyl group. R ¹ is preferably a hydrogen atom, a hydroxyl group, a methyl group, an ethyl group, a 1-hydroxymethyl group, a 2-hydroxymethyl group, a 1-hydroxyethyl group, or a 2-hydroxyethyl group.
Moreover, in said formula (1), as a C1-C6 alkylene group of R < ² >, a methylene group, ethylene group, propane- 1, 3- diyl group, butane- 1, 4- diyl group, heptane-1 , 5-diyl group and hexane-1,6-diyl group. R ² is preferably a hydroxyl group, a methylene group, an ethylene group, a 1-hydroxymethyl group, a 2-hydroxymethyl group, a 1-hydroxyethyl group, or a 2-hydroxyethyl group. In said formula (1), it is preferable that it is 1 or 2 as an integer of 0-2 of n.
Moreover, in said formula (3), as a C1-C6 alkylene group of R <3>, a methylene group, ethylene group, a propane- 1, ^3- diyl group, butane- 1, 4- diyl group, heptane-1 , 5-diyl group and hexane-1,6-diyl group. R ³ is preferably a hydroxyl group, a methylene group, an ethylene group, a 1-hydroxymethyl group, a 2-hydroxymethyl group, a 1-hydroxyethyl group, or a 2-hydroxyethyl group.

  Specific examples of the compound represented by the above formula (1) include 2,2-bis (aminomethyl) -n-butyric acid represented by the following formula (1a) and the following formula (1b). 2,2-bis (aminomethyl) propionic acid, aminopivalic acid represented by the following formula (1c), β-aminoisobutyric acid represented by the following formula (1d), and the like. Or two or more of them may be used in combination.

  Specific examples of the compound represented by the above formula (2) include 2-amino-2-methyl-n-butyric acid represented by the following formula (2a) and the following formula (2b). 2-aminoisobutyric acid, glycine represented by the following formula (2c), DL-2-aminobutyric acid represented by the following formula (2d), DL-threonine represented by the following formula (2e), and the following formula (2f) DL-serine represented by the following formula, DL-norvaline represented by the following formula (2f), and the like, and these may be used alone or in combination of two or more.

  Specific examples of the compound represented by the above formula (3) include DL-3-aminobutyric acid represented by the following formula (3a) and β-aminovaleric acid represented by the following formula (3b). , 6-aminohexane represented by the following formula (3c), and the like may be used, and these may be used alone or in combination of two.

The fatty acid silver salt (B) is preferably an α-amino acid silver salt. Moreover, it is preferable that it has a hydroxyl group.
Therefore, among the above, the fatty acid silver salt (B) obtained is at least one selected from the group consisting of 2-aminoisobutyric acid, DL-threonine, DL-serine, DL-norvaline and 6-aminohexane. Conductive composition of the present invention containing at least one selected from the group consisting of certain 2-aminoisobutyric acid silver salt, DL-threonine silver salt, DL-serine silver salt, DL-norvaline silver salt and 6-aminohexane silver salt It is preferable because a conductive film formed using a material can be formed at a lower temperature and in a shorter time.

On the other hand, silver oxide used in the above reaction is similar to the silver oxide employed in the conductive composition of the present invention (A), silver oxide (I), i.e., an Ag ₂ O.

The fatty acid silver salt (B) used in the conductive composition of the present invention is obtained by reacting the fatty acid B ′ having one or more amino groups described above with silver oxide, and the following formula ( The compounds represented by I) to (III) are preferred.
For example, when the compounds represented by the above formulas (1) to (3) are used, this reaction is not particularly limited as long as the reaction represented by the following reaction formula proceeds. A method of proceeding while pulverizing and a method of reacting the fatty acid B ′ after pulverizing the silver oxide are preferred. Specifically, as the former method, the above-mentioned silver oxide and a solution obtained by dissolving the fatty acid B ′ with a solvent are kneaded with a ball mill or the like to grind the solid silver oxide at room temperature, The reaction is preferably performed for about 1 to 24 hours, preferably 2 to 8 hours.

  Each symbol in formula (I), formula (II) and formula (III) has the same meaning as in formula (1), formula (2) and formula (3).

Specific examples of the solvent for dissolving the fatty acid B ′ include butyl carbitol, methyl ethyl ketone, isophorone, α-terpineol, and the like. These may be used alone or in combination of two or more. May be.
Of these, using isophorone and / or α-terpineol as a solvent improves the thixotropy of the conductive composition of the present invention containing the fatty acid silver salt (B) obtained by the above reaction.

  The conductive composition of the present invention is a composition containing the above-described silver oxide (A) and fatty acid silver salt (B), but the content of the fatty acid silver salt (B) is 100 masses of silver oxide (A). It is preferable that it is 0.1-50 mass parts with respect to a part, and it is more preferable that it is 0.5-50 mass parts. This is because the specific resistance of the conductive film formed using the conductive composition obtained is lower.

In the present invention, since such a fatty acid silver salt (B) is used, a conductive film having a small specific resistance can be formed at a low temperature in a short time, and the conductive film can be satisfactorily applied to a substrate having low heat resistance. Can be formed.
Specifically, a conductive film having a specific resistance of 10 × 10 ⁻⁶ Ω · cm or less can be formed in about 30 minutes at a temperature of about 150 ° C. Here, in the present specification, the specific resistance is determined by a four-terminal four-probe method using a low resistivity meter (Lorestar GP, manufactured by Mitsubishi Chemical Corporation) for a conductive film dried at 150 ° C. for 30 minutes. It is a value obtained by measuring resistance (volume specific resistance value).
This is presumably because the decomposition (reduction) into silver by heat treatment is greatly accelerated by the presence of an amino group in the molecule of the fatty acid silver salt (B). Moreover, it is clear from the result of thermogravimetry (TGA) that it is more easily reduced than the tertiary fatty acid silver salt.
Moreover, as will be described later, the conductive composition of the present invention also has an effect that a film can be formed without containing a film-forming resin.

<Fatty acid silver salt (C)>
In the conductive composition of the present invention, a fatty acid silver salt (C) can be used.
The fatty acid silver salt (C) is a fatty acid silver salt having one or more, preferably two or more hydroxyl groups, and having no amino group. Specifically, the fatty acid silver salt has one or more hydroxyl groups shown below. And a fatty acid having no amino group (hereinafter also referred to as “fatty acid C ′”) and silver oxide are obtained.

  The fatty acid C ′ used in the reaction is not particularly limited as long as it is a fatty acid having one or more, preferably two or more hydroxyl groups, and having no amino group. For example, the following formulas (4) to (6) ).

In formula (4), n represents an integer of 0 to 2, R ⁴ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ⁵ represents an alkylene group having 1 to 6 carbon atoms. When n is 0 or 1, the plurality of R ⁵ may be the same or different. When n is 2, the plurality of R ⁴ may be the same or different.
In formula (5), R ⁴ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and a plurality of R ⁴ may be the same or different.
In formula (6), R ⁴ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ⁶ represents an alkylene group having 1 to ⁶ carbon atoms. A plurality of R ⁴ may be the same or different.

In the formula (4) to (6), the alkyl group having 1 to 10 carbon atoms R ^4, a methyl group, an ethyl group, n- propyl group, n- butyl group, n- pentyl group, n- hexyl group , N-heptyl group, n-octyl group, n-nonyl group and n-decyl group. R ¹ is preferably a hydrogen atom, a methyl group, or an ethyl group.
In the above formula (4), the alkylene group having 1 to 6 carbon atoms of R ⁵ is methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, heptane-1 , 5-diyl group and hexane-1,6-diyl group. R ⁵ is preferably a methylene group or an ethylene group. In the above formula (4), the integer of 0 to 2 of n is preferably 1 or 2.
Further, in the above formula (6), the alkylene group having 1 to 6 carbon atoms R ^6, methylene group, ethylene group, propane-1,3-diyl, butane-1,4-diyl group, heptane -1 , 5-diyl group and hexane-1,6-diyl group. R ⁶ is preferably a methylene group or an ethylene group.

  Specific examples of the compound represented by the above formula (4) include 2,2-bis (hydroxymethyl) -n-butyric acid represented by the following formula (4a) and the following formula (4b). 2,2-bis (hydroxymethyl) propionic acid, hydroxypivalic acid represented by the following formula (4c), β-hydroxyisobutyric acid represented by the following formula (1d), and the like. You may use independently and may use 2 or more types together.

  Specific examples of the compound represented by the above formula (5) include 2-hydroxy-2-methyl-n-butyric acid represented by the following formula (5a) and the following formula (5b). Examples include 2-hydroxyisobutyric acid, glycolic acid represented by the following formula (5c), DL-2-hydroxybutyric acid represented by the following formula (5d), etc., and these may be used alone. More than one species may be used in combination.

  Specific examples of the compound represented by the above formula (6) include DL-3-hydroxybutyric acid represented by the following formula (6a) and β-hydroxyvaleric acid represented by the following formula (6b). These may be used, and these may be used alone or in combination of two.

  Among these, the fatty acid obtained is at least one selected from the group consisting of 2,2-bis (hydroxymethyl) -n-butyric acid, 2,2-bis (hydroxymethyl) propionic acid and hydroxypivalic acid. Silver salt (C) 2,2-bis (hydroxymethyl) -n-butyric acid silver salt, 2,2-bis (hydroxymethyl) propionic acid silver salt and hydroxypivalic acid silver salt It is preferable because the conductive film formed using the conductive composition of the present invention containing one kind can be formed at a lower temperature and in a shorter time.

On the other hand, silver oxide used in the above reaction is similar to the silver oxide employed in the conductive composition of the present invention (A), silver oxide (I), i.e., an Ag ₂ O.

The fatty acid silver salt (C) used in the conductive composition of the present invention is obtained by reacting a fatty acid C ′ having at least one hydroxyl group and having no amino group with silver oxide. Compounds represented by the following formulas (IV) to (VI) in the reaction formulas shown are preferable.
For example, when the compounds represented by the above formulas (4) to (6) are used, this reaction is not particularly limited as long as the reaction represented by the following reaction formula proceeds. A method of proceeding while pulverizing and a method of reacting the fatty acid C ′ after pulverizing the silver oxide are preferred. Specifically, as the former method, the above silver oxide and a solution obtained by dissolving the above fatty acid with a solvent are kneaded with a ball mill or the like, and the above solid silver oxide is pulverized at room temperature, The reaction is preferably performed for about 24 hours, preferably 2 to 8 hours.

  Each symbol in formula (IV), formula (V), and formula (VI) has the same meaning as in formula (4), formula (5), and formula (6).

  As a solvent for dissolving the fatty acid C ′, a solvent for dissolving the fatty acid B ′ can be used.

  In the present invention, when such a fatty acid silver salt (C) is used, a conductive film having a small specific resistance can be formed at a lower temperature and in a shorter time, and it is also excellent in conductivity even on a substrate having low heat resistance. A film can be formed.

<Secondary fatty acid silver salt (D)>
In the conductive composition of the present invention, a secondary fatty acid silver salt (D) can be used.
The secondary fatty acid silver salt (D) is obtained using a secondary fatty acid having a boiling point of 200 ° C. or lower. Specifically, the secondary fatty acid having a boiling point of 200 ° C. or lower (hereinafter referred to as “2”) is shown below. Grade fatty acid D ′ ”) and silver oxide.

  The secondary fatty acid D ′ used for the reaction of the secondary fatty acid silver salt (D) is not particularly limited as long as the boiling point is a secondary fatty acid having a boiling point of 200 ° C. or lower, and specific examples thereof are represented by the following formula (7). And the compounds represented.

In formula (7), R ⁷ represents an alkyl group having 1 to 6 carbon atoms, and R ⁸ represents an alkyl group having 1 to 10 carbon atoms.

In the above formula (7), the alkyl group having 1 to 6 carbon atoms R ^7, methyl group, ethyl group, n- propyl group, n- butyl group, n- pentyl group, and n- hexyl. R ⁷ is preferably a methyl group or an ethyl group.
Further, in the above formula (7), the alkyl group having 1 to 10 carbon atoms R ^8, in addition to an alkyl group having 1 to 6 carbon atoms of the above R ^7, n- heptyl, n- octyl, n- Nonyl group and n-decyl group are mentioned. R ⁸ is preferably a methyl group, an ethyl group, or an n-propyl group.

In the present invention, specific examples of the carboxylic acid represented by the formula (7) include 2-methylpropanoic acid (also known as isobutyric acid) and 2-methylbutanoic acid (also known as 2-methylbutyric acid). , 2-methylpentanoic acid, 2-methylheptanoic acid, 2-ethylbutanoic acid; and the like.
Among these, 2-methylpropanoic acid and 2-methylbutanoic acid are the obtained secondary fatty acid silver salt (D), and the present invention contains 2-methylpropanoic acid silver salt and 2-methylbutanoic acid silver salt. It is preferable because the conductive film formed using the conductive composition can be formed at a lower temperature and in a shorter time.

On the other hand, the silver oxide used for the reaction of the secondary fatty acid silver salt (D) is silver oxide (I), that is, Ag ₂ O, like the silver oxide (A) used in the conductive composition of the present invention. .

The secondary fatty acid silver salt (D) used in the conductive composition of the present invention is obtained by reacting the above-described secondary fatty acid D ′ having a boiling point of 200 ° C. or less and silver oxide, in the reaction formula shown below. A compound represented by the following formula (VII) is preferable.
This reaction is not particularly limited, for example, when the compound represented by the above formula (7) is used as long as the reaction represented by the following reaction formula proceeds, while pulverizing the silver oxide. A method of proceeding or a method of reacting the secondary fatty acid D ′ after pulverizing the silver oxide is preferred. Specifically, as the former method, the above silver oxide and a solution of the above secondary fatty acid in a solvent are kneaded with a ball mill or the like, and the solid silver oxide is pulverized at room temperature, The reaction is preferably performed for about 1 to 24 hours, preferably 2 to 8 hours.

In formula (VII), R ⁷ represents an alkyl group having 1 to 6 carbon atoms, and R ⁸ represents an alkyl group having 1 to 10 carbon atoms.

  As a solvent for dissolving the secondary fatty acid D ′, a solvent for dissolving the fatty acid B ′ can be used.

  In the present invention, when such a secondary fatty acid silver salt (D) is used, a conductive film having a low specific resistance can be formed at a lower temperature and in a shorter time, and it is also suitable for a substrate having low heat resistance. A conductive coating can be formed.

  As described above, the conductive composition of the present invention contains the silver oxide (A) and the fatty acid silver salt (B), and the fatty acid silver salt (C) or the secondary fatty acid silver salt (D). And may contain both the fatty acid silver salt (C) and the secondary fatty acid silver salt (D).

In the conductive composition of the present invention, when both the fatty acid silver salt (C) and the secondary fatty acid silver salt (D) are contained, the number of moles C of the fatty acid silver salt (C) and the secondary The molar ratio (B / C) of the fatty acid silver salt (D) with the number of moles D is preferably 1/1 to 15/1, and more preferably 3/1 to 15/1. It is preferable for the molar ratio to be within this range because the specific resistance of the conductive film formed using the resulting conductive composition will be lower.
For the same reason, the molar ratio between the mole number A of the silver oxide (A) and the sum of the mole number C of the fatty acid silver salt (C) and the mole number D of the secondary fatty acid silver salt (D) ( A / B + C) is preferably 2/1 to 25/1, and more preferably 2/1 to 15/1.

The conductive composition of the present invention can form a film that exhibits the effects of the present invention even if it does not contain a film-forming resin.
However, it may further contain a film-forming resin.
Specific examples of the film-forming resin include an epoxy resin, a urethane resin, a silicone resin, a polyester urethane resin, a silicone-modified acrylic resin, and a phenol resin.
Among these, it is possible to form a conductive film having high adhesion to the substrate with a small amount, and as a result, it is easy to maintain a small specific resistance of the conductive composition of the present invention, A polyester urethane resin is preferred.

The electrically conductive composition of this invention may contain additives, such as a metal powder and a reducing agent, as needed.
Specific examples of the metal powder include copper, silver, and aluminum. Among these, copper and silver are preferable. Moreover, it is preferable that it is a metal powder with a particle size of 0.01-10 micrometers.
Specific examples of the reducing agent include ethylene glycols.
In addition to the fatty acid silver salt (B), the fatty acid silver salt (C), and the secondary fatty acid silver salt (D), the conductive composition of the present invention is a silver neodecanoate from the viewpoint of improving adhesiveness. Other fatty acid silver salts such as a salt may be contained in a smaller number of moles than the fatty acid silver salt (B), the fatty acid silver salt (C) and the secondary fatty acid silver salt (D).

The method for producing the conductive composition of the present invention is not particularly limited, and the silver oxide (A) and the fatty acid silver salt (B), the fatty acid silver salt (C) which may be optionally contained, and the second grade. Examples include a method of mixing the fatty acid silver salt (D), the polyester urethane resin (E), and the additive with a roll, a kneader, an extruder, a universal agitator, or the like.
In the present invention, as described above, the silver oxide used in the reaction of the fatty acid silver salt (B), the fatty acid silver salt (C) and the secondary fatty acid silver salt (D) is the same as the silver oxide (A). Since it is the same, the manufacturing method of the electrically conductive composition of this invention is the said fatty acid silver salt (B) synthesize | combined previously, and the said fatty acid silver salt (C) and the said secondary fatty acid silver salt (D) as needed. In addition to the method of mixing the silver oxide (A) with the fatty acid (fatty acid C ′) having one or more amino groups used for the production of an excessive amount of the silver oxide (A) and the fatty acid silver salt (B). , And if necessary, a fatty acid having one or more hydroxyl groups used for the production of the fatty acid silver salt (C), and a secondary fatty acid having a temperature of 200 ° C. or less used for the production of the secondary fatty acid silver salt (D) (2 Grade fatty acid D ′) and the above fatty acid silver salt during mixing B), or a method of synthesizing the fatty acid silver salt (C) and the secondary fatty acid silver salt (D).

The method for producing a substrate with a conductive film of the present invention comprises a coating film forming step of coating the conductive composition of the present invention on a substrate to form a coating film, and heat-treating the obtained coating film. And a heat treatment step for obtaining a conductive coating, and a method for producing a substrate with a conductive coating.
The substrate with a conductive coating of the present invention can be obtained by the method for producing a substrate with a conductive coating of the present invention.
Below, a coating-film formation process and a heat processing process are explained in full detail.

<Coating film formation process>
The said coating-film formation process is a process of apply | coating the electrically conductive composition of this invention on a base material, and forming a coating film.
Here, as the base material, in addition to the base material having low heat resistance exemplified above, for example, a film such as polyethylene naphthalate or polyimide; a substrate such as copper plate, copper foil, glass, epoxy, or paper; .
The conductive composition of the present invention is formed into a solution using a solvent such as α-terpineol exemplified above as necessary, and then coated on a substrate by the coating method exemplified below to form a coating film. To do.
Specific examples of the coating method include inkjet, screen printing, gravure printing, offset printing, letterpress printing, and the like.

<Heat treatment process>
The said heat treatment process is a process of heat-treating the coating film obtained at the said coating-film formation process, and obtaining a conductive film.
In the present invention, the fatty acid silver salt (B) (and the fatty acid silver salt (C) and the secondary fatty acid silver salt (D), if these are contained) is also heat-treated by heat-treating the coating film. The fatty acid generated by the decomposition or the decomposition product thereof is volatilized, while a part of the fatty acid generated by the decomposition reacts with the silver oxide (A) to react again with the fatty acid silver salt (B) (fatty acid silver salt). (C) and secondary fatty acid silver salt (D)) are produced, and the conductive film (silver film) of the present invention is formed by repeating the cycle in which it is reduced (decomposed into silver and fatty acid).

  In the present invention, the heat treatment is preferably a heat treatment at a temperature of 100 to 250 ° C. for several seconds to several tens of minutes, and a heat treatment at 100 to 150 ° C. for 30 to 60 minutes. More preferably, it is more preferably a treatment of heating at about 150 ° C. for about 30 minutes. When the heat treatment temperature and time are within this range, a good conductive film can be formed even on a substrate having low heat resistance. This is because, as described above, the conductive composition of the present invention uses the fatty acid silver salt (B).

  In the present invention, since the coating film obtained in the coating film forming step can form a conductive coating film by the cycle even by irradiation with ultraviolet rays or infrared rays, the heat treatment step is performed by irradiation with ultraviolet rays or infrared rays. It may be due to.

  Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to this.

(Examples 1-9)
In a ball mill, silver oxide (A) (silver oxide (I)), fatty acid silver salt (B), fatty acid silver salt (C), secondary fatty acid silver salt (D) and α- Terpineol was added at a weight shown in Table 1 below, and these were mixed to prepare a conductive composition.
In addition, 2-aminoisobutyric acid silver salt, DL-threonine silver salt, DL-serine silver salt, DL-norvaline silver salt, and 6-aminohexanoic acid silver salt are 2-aminoisobutyric acid, DL-threonine, DL- It is obtained by the reaction of serine, DL-norvaline, 6-aminohexanoic acid and silver (I) oxide.
The 2,2-bis (hydroxymethyl) -n-butyric acid silver salt is obtained by the reaction of 2,2-bis (hydroxymethyl) -n-butyric acid, which is a fatty acid, with silver (I) oxide. .
Moreover, 2-methylpropanoic acid silver salt is obtained by reaction of 2-methylpropanoic acid (isobutyric acid) which is a fatty acid and silver oxide (I). In Table 1 below, the series and boiling point of isobutyric acid used for the reaction of the fatty acid silver salt are described.
Next, the prepared conductive composition was applied by screen printing onto a 100 μm thick PET film (Lumirror S56, manufactured by Toray Industries, Inc.) as a base material to form a coating film, and then heated at 150 ° C. in an oven at 30 ° C. The substrate was dried for a minute to produce a substrate with a conductive coating.

(Comparative Example 1)
A conductive composition was prepared in the same manner as in Example 9 except that the fatty acid silver salt (B) was not used, and a substrate with a conductive coating was prepared.

  About the obtained electroconductive film of each base material, the specific resistance was measured with the following method. The result is shown first.

<Resistivity>
For each conductive film obtained by drying at 150 ° C. for 30 minutes, the specific resistance (volume resistivity) is measured by a four-terminal four-probe method using a low resistivity meter (Lorestar GP, manufactured by Mitsubishi Chemical Corporation). did. The results are shown in Table 1 below.

From the results shown in Table 1, the conductive composition (Comparative Example 1) containing no fatty acid silver salt (B) having one or more amino groups has high specific resistance under the drying conditions of 150 ° C. for 30 minutes. I understood that.
On the other hand, the conductive composition containing the fatty acid silver salt (B) having at least one amino prepared in Examples 1 to 9 has a specific resistance even when the drying condition after coating is 150 ° C. for 30 minutes. It was found that a conductive film having a small thickness can be formed.

Claims (6)

Containing silver oxide (A) and a fatty acid silver salt (B) having one or more amino groups ,
The fatty acid silver salt (B) is obtained by reacting a fatty acid B ′ having one or more amino groups with silver oxide,
The electrically conductive composition whose said fatty acid B 'is a compound represented by either of following formula (1)-(3) .

In formula (1), n represents an integer of 0 to 2, R ¹ represents a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 10 carbon atoms which may have a hydroxyl group, and R ² represents 1 to 6 carbon atoms. Represents an alkylene group. When n is 0 or 1, the plurality of R ² may be the same or different from each other. When n is 2, the plurality of R ¹ may be the same or different.
In Formula (2), R ¹ represents a hydrogen atom, a hydroxyl group, or an alkyl group having 1 to 10 carbon atoms which may have a hydroxyl group, and a plurality of R ¹ may be the same or different.
In Formula (3), R ¹ represents a hydrogen atom, a hydroxyl group or an alkyl group having 1 to 10 carbon atoms which may have a hydroxyl group, and R ³ represents an alkylene group having 1 to 6 carbon atoms. The plurality of R ¹ may be the same or different.   2. The conductive composition according to claim 1, wherein the content of the fatty acid silver salt (B) is 0.1 to 50 parts by mass with respect to 100 parts by mass of the silver oxide (A). A fatty acid silver salt (C) having at least one hydroxyl group and having no amino group, and / or a secondary fatty acid silver salt obtained by using a secondary fatty acid having a boiling point of 200 ° C. or less and having no amino group ( D) ,
The fatty acid silver salt (C) is selected from the group consisting of 2,2-bis (hydroxymethyl) -n-butyric acid silver salt, 2,2-bis (hydroxymethyl) propionic acid silver salt, and hydroxypivalic acid silver salt The electrically conductive composition according to claim 1, wherein the electrically conductive composition is at least one kind . The electrically conductive composition of Claim 3 whose said secondary fatty acid silver salt (D) is 2-methylpropanoic acid silver salt. The coating-film formation process which apply | coats the electrically conductive composition in any one of Claims 1-4 on a base material, and forms a coating film, The heat processing process which heat-processes the obtained coating film and obtains a conductive film And a method for producing a substrate with a conductive coating. The manufacturing method of the base material with a conductive film of Claim 5 whose said heat processing is a process heated to the temperature of 100-250 degreeC.