Metal particle composition

Abstract

Provided is a metal particle composition that contains: metal particles (A); a compound (B) that includes a structure represented by general formula (I); and a solvent (C) for which the Hansen solubility parameter polarity term δP is 3.0-17.0 and the hydrogen bonding term δH is 6.6-42.5. (In general formula (I), R1 and R2 each independently denote a hydrogen atom, an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, an alkenyl group having 2-6 carbon atoms, an aryl group or an aralkyl group. R3 and R4 each independently denote a hydrogen atom, an alkyl group having 1-6 carbon atoms, an alkoxy group having 1-6 carbon atoms, an alkenyl group having 2-6 carbon atoms, an alkenyloxy group having 2-6 carbon atoms, an aryl group or an aralkyl group.)

Description

metal particle composition

[0001] The present invention relates to a metal particle composition.

[0002] BACKGROUND ART Metal particles have conventionally been used in a variety of applications, including as raw material powders for powder metallurgy, firing pastes for multilayer ceramic capacitors, and materials used in conductive pastes and conductive inks for forming wiring by inkjet printing or the like.

[0003] In recent years, there has been an increasing need for finer metal particles. The main reason for this is that finer metal particles have a lower melting point, allowing sintering of metal particles at lower temperatures. By finer metal particles, it becomes possible to apply metal particles and pastes containing them to substrates with low heat resistance, which were previously difficult to apply. Furthermore, as electronic components become more miniaturized, more precise electronic circuits are required, and metal particles with smaller particle sizes are required for wiring formation applications.

[0004] On the other hand, miniaturization of metal particles increases the surface energy of the particles. As a result, dispersion stability decreases when the particles are made into a paste, so improving dispersibility becomes an issue. To solve these problems, Patent Document 1 proposes a method of coating the particle surfaces with fatty acids such as fatty acids and fatty acid alkanolamides to suppress aggregation between particles. Patent Document 2 proposes a method of modifying the particle surfaces with alkylamines. Patent Document 3 describes a technology that uses a compound having a specific structure containing an unsaturated double bond together with metal particles.

[0005] JP 2021-031738 A JP 2014-194057 A International Publication No. 2022 / 019069 A

[0006] However, in the conventional methods of coating with fatty acids or alkylamines as described in Patent Documents 1 and 2, the alkyl moieties protrude outward from the particles, making the entire particle hydrophobic, resulting in a problem of reduced dispersion stability in polar solvents. On the other hand, the method described in Patent Document 3 makes it possible to obtain a metal particle composition with excellent oxidation resistance. However, in recent years, with the miniaturization of metal particles, improving the dispersion stability of metal particles in metal compositions has become an issue. Patent Document 3 does not consider the dispersion stability of metal particle compositions.

[0007] The present invention has been made in view of the above-mentioned conventional problems, and has an object to provide a metal particle composition that has excellent dispersion stability even in a highly polar solvent.

[0008] As a result of intensive research to achieve the above-mentioned object, the inventors discovered that a metal particle composition with excellent dispersion stability can be obtained by using a compound having a specific structure including an unsaturated double bond together with metal particles, and by using a solvent in which the polar term δP and hydrogen bond term δH of the Hansen solubility parameter are in specific numerical ranges, and thus completed the present invention.

[0009] That is, the present invention provides the following items [1] to [9]: [1] A metal particle composition comprising metal particles (A), a compound (B) having a structure represented by the following general formula (I), and a solvent (C) having a Hansen solubility parameter polarity term δP of 3.0 to 17.0 and a hydrogen bonding term δH of 6.6 to 42.5.

[0010]

[0011] (In general formula (I), R １ and R ２ R each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. ３ and R ４each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkenyloxy group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. [2] The metal particle composition according to [1] above, wherein the compound (B) having a structure represented by general formula (I) is a compound having a structure represented by the following general formula (II):

[0012]

[0013] (In general formula (II), R ５ and R ６ R each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. ７ and R ８ R each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkenyloxy group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. ９represents a hydrogen atom; a (meth)acrylic group; an alkyl group having 1 to 6 carbon atoms; an alkenyl group having 2 to 6 carbon atoms; an aryl group; or an aralkyl group.) [3] The metal particle composition according to [1] or [2] above, wherein the metal particles (A) are particles of at least one metal selected from the group consisting of silver and copper. [4] The metal particle composition according to any one of [1] to [3] above, wherein the solvent (C) comprises at least one selected from the group consisting of water and an alcohol. [5] The metal particle composition according to any one of [1] to [4] above, wherein the solvent (C) comprises at least one selected from the group consisting of water, ethylene glycol, dipropylene glycol, 3-methyl-1,3-butanediol, 3-methoxy-3-methyl-1-butanol, and α-terpineol. [6] The metal particle composition according to any one of [1] to [5], wherein the content of the compound (B) is 0.1 to 10 parts by mass relative to 100 parts by mass of the metal particles (A). [7] The metal particle composition according to any one of [1] to [6], wherein the content of the solvent (C) is 10 to 20,000 parts by mass relative to 100 parts by mass of the metal particles (A). [8] A method for producing a metal particle composition comprising metal particles (A), a compound (B) having a structure represented by general formula (I), and a solvent (C) having a Hansen solubility parameter polarity term δP of 3.0 to 17.0 and a hydrogen bonding term δH of 6.6 to 42.5, the method comprising a mixing step of mixing the metal particles (A), the compound (B), and the solvent (C). (In general formula (I), R １ and R ２ R each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. ３ and R ４ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkenyloxy group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. [9] The method for producing a metal particle composition according to the above [8], wherein in the mixing step, the metal particles (A) and the compound (B) are mixed together, and then the mixture is mixed with the solvent (C).

[0014] According to the present invention, it is possible to provide a metal particle composition that has excellent dispersion stability even in a highly polar solvent.

[0015] The following description will be given based on an example of an embodiment of the present invention (hereinafter, sometimes referred to as "the present embodiment"). However, the embodiment shown below is an example for embodying the technical idea of ​​the present invention, and the present invention is not limited to the following description.

[0016] [Metal Particle Composition] A metal particle composition according to an embodiment of the present invention is a metal particle composition comprising metal particles (A), a compound (B) having a structure represented by the following general formula (I), and a solvent (C) having a Hansen solubility parameter polarity term δP of 3.0 to 17.0 and a hydrogen bonding term δH of 6.6 to 42.5:

[0017] (In general formula (I), R １ and R ２ R each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. ３ and R ４ each independently represents a hydrogen atom; an alkyl group having 1 to 6 carbon atoms; an alkoxy group having 1 to 6 carbon atoms; an alkenyl group having 2 to 6 carbon atoms; an alkenyloxy group having 2 to 6 carbon atoms; an aryl group; or an aralkyl group.

[0018] The metal particle composition described above uses a compound having a specific structure containing an unsaturated double bond together with metal particles, and a solvent in which the polarity term δP and the hydrogen bond term δH of the Hansen solubility parameter fall within specific numerical ranges, thereby obtaining a metal particle composition with excellent dispersion stability. The reason for this is believed to be, but is not limited to, the following: The compound having an unsaturated double bond interacts with the metal particles, resulting in highly polar oxygen atom sites being located on the outside of the particles. As a result, the affinity with highly polar solvents and solvents with strong hydrogen bonding properties is increased, suppressing particle aggregation and resulting in excellent dispersion stability even in highly polar solvents.

[0019] The metal particle composition may be a mixture of the metal particles (A) and the compound (B), or may be one in which at least a portion of the compound (B) adheres to the metal particles (A). Alternatively, the surface of the metal particles (A) may be coated with the compound (B). The metal particle composition may be a mixture of the compound (B) and the metal particles (A), and a portion of the compound (B) may adhere to or coat the surface of the metal particles (A).

[0020] <Metal Particles (A)> As the metal particles (A) contained in the metal particle composition, various particles containing a metal can be used without any particular limitation. Examples of the metal contained in the metal particles (A) include at least one selected from the group consisting of copper, silver, iron, nickel, tin, lead, and titanium. The metal may be an alloy as long as it contains any of the above elements. The metal particles (A) may contain elements other than the metal element, such as hydrogen, oxygen, carbon, nitrogen, and sulfur, as long as it contains any of the above elements. The metal particles (A) may be mixed particles containing any two or more of copper, silver, iron, nickel, tin, lead, and titanium. The metal particles (A) are preferably made of at least one metal selected from the group consisting of silver, copper, and iron, and more preferably made of at least one metal selected from the group consisting of silver and copper. Among these, copper or silver is preferred, and silver is more preferred, from the viewpoint of easily demonstrating the high performance inherent to metals, such as conductivity. The metal particles (A) preferably contain copper or silver, and more preferably contain silver.

[0021] The shape of the metal particles (A) is not particularly limited, and examples thereof include granular, pellet, flake, spherical, needle, stick, and disc shapes. Among these, spherical shapes are preferred. When the metal particles (A) are spherical, the flowability is more likely to be improved.

[0022] The average particle size of the metal particles (A) is not particularly limited, but is preferably 1 nm to 100 μm, more preferably 10 nm to 10 μm, and even more preferably 30 nm to 1 μm. In this specification, the average particle size of the metal particles (A) is the primary particle size, and the primary particle size can be measured, for example, from images obtained using an electron microscope, optical microscope, digital microscope, or the like. In this embodiment, the average particle size of the metal particles (A) can be calculated in accordance with JIS H 7804:2005. Specifically, the method described in the Examples can be followed.

[0023] Such metal particles (A) are made by pulverizing metal into particles and can be produced by various known production methods. Commercially available metal particles (A) may also be used.

[0024] The content of metal particles (A) in the total amount of metal particles (A) and compound (B) is preferably 70 to 99.9 mass%, more preferably 80 to 99.8 mass%, and even more preferably 90 to 99.7 mass%. When the content of metal particles (A) is equal to or greater than the above lower limit, it becomes easier to secure the required amount of metal and also to ensure required physical properties such as conductivity. When the content of metal particles (A) is equal to or less than the above upper limit, the content of compound (B) becomes relatively high, which makes it easier to improve the dispersion stability of the metal particle composition. The content of metal particles (A) in the metal particle composition is preferably 0.01 to 90 mass%. When it is 0.01 mass% or more, the effects attributable to the metal particles (A) are well manifested, and when it is 90 mass% or less, the dispersion stability is further improved. From these viewpoints, the content of the metal particles (A) in the metal particle composition is more preferably 0.01 to 50 mass%, even more preferably 0.1 to 10 mass%, even more preferably 0.1 to 5 mass%, and even more preferably 0.2 to 3 mass%.

[0025] <Compound (B) Having a Structure Represented by General Formula (I)> As described above, compound (B) has a structure represented by the following general formula (I).

[0026] In the above general formula (I), R １ and R ２each independently represents a hydrogen atom; an alkyl group having 1 to 6 carbon atoms; an alkoxy group having 1 to 6 carbon atoms; an alkenyl group having 2 to 6 carbon atoms; an aryl group; or an aralkyl group.

[0027] R １ and R ２ Examples of the alkyl group having 1 to 6 carbon atoms represented by include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, an n-hexyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

[0028] R １ and R ２ Examples of the alkoxy group having 1 to 6 carbon atoms represented by include a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, a butyloxy group, and a hexyloxy group.

[0029] R １ and R ２ Examples of the alkenyl group having 2 to 6 carbon atoms represented by include a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a pentenyl group, a prenyl group, a hexenyl group (such as a cis-3-hexenyl group), and a cyclohexenyl group.

[0030] R １ and R ２ From the viewpoint of ease of production, the aryl group represented by is preferably an aryl group having 6 to 18 carbon atoms, and examples thereof include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group.

[0031] R １ and R ２ From the viewpoint of ease of production, the aralkyl group represented by is preferably an aralkyl group having 7 to 18 carbon atoms, and examples thereof include a benzyl group, a 2-phenylethyl group, a 2-naphthylethyl group, and a diphenylmethyl group.

[0032] Among these, from the viewpoint of improving the dispersion stability of the metal particle composition, R １ and R ２are each independently preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, even more preferably a hydrogen atom or a methyl group, and still more preferably a methyl group.

[0033] In general formula (I), R ３ and R ４ each independently represents a hydrogen atom; an alkyl group having 1 to 6 carbon atoms; an alkoxy group having 1 to 6 carbon atoms; an alkenyl group having 2 to 6 carbon atoms; an alkenyloxy group having 2 to 6 carbon atoms; an aryl group; or an aralkyl group.

[0034] R ３ and R ４ Examples of the alkenyloxy group having 2 to 6 carbon atoms represented by include a vinyloxy group, a 1-propenyloxy group, a 2-n-propenyloxy group (allyloxy group), a 1-n-butenyloxy group, and a prenyloxy group.

[0035] R ３ and R ４ Examples of the alkyl group having 1 to 6 carbon atoms, the alkoxy group having 1 to 6 carbon atoms, the alkenyl group having 2 to 6 carbon atoms, the aryl group and the aralkyl group represented by are the same as those of the above R １ and R ２ The explanation is the same as that for (1), and a duplicate explanation will be omitted.

[0036] Among these, R ３ and R ４ are each independently preferably a hydrogen atom; an alkyl group having 1 to 3 carbon atoms; an alkenyl group having 2 or 3 carbon atoms; or an aryl group, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom. Among these, from the viewpoint of improving the dispersion stability of the resulting metal particle composition, R ３ and R ４ are preferably all hydrogen atoms.

[0037] As the compound (B) containing the structure represented by general formula (I), it is preferable that it is a compound containing the structure represented by the following general formula (II), from the viewpoint of improving the dispersion stability of the metal particle composition.

[0038] (In general formula (II), R ５ and R ６ R each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. ７ and R ８ R each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkenyloxy group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. ９ represents a hydrogen atom; a (meth)acrylic group; an alkyl group having 1 to 6 carbon atoms; an alkenyl group having 2 to 6 carbon atoms; an aryl group; or an aralkyl group.

[0039] In general formula (II), R ５ and R ６ Examples of the alkyl group having 1 to 6 carbon atoms, the alkoxy group having 1 to 6 carbon atoms, the alkenyl group having 2 to 6 carbon atoms, the aryl group, and the aralkyl group represented by are the same as those described above for R １ and R ２ It is the same as for R ７ and R ８ Examples of the alkyl group having 1 to 6 carbon atoms, the alkoxy group having 1 to 6 carbon atoms, the alkenyl group having 2 to 6 carbon atoms, the alkenyloxy group having 2 to 6 carbon atoms, the aryl group, and the aralkyl group represented by are the same as those of the above R ３ and R ４ It is the same as for R ９ Examples of the alkyl group having 1 to 6 carbon atoms, the alkenyl group having 2 to 6 carbon atoms, the aryl group, and the aralkyl group represented by are the same as those described above for R １ and R ２ In particular, from the viewpoint of improving the dispersion stability of the resulting metal particle composition, R ９ is preferably a hydrogen atom.

[0040] Compound (B) is, for example, a compound having a molecular structure represented by at least one of the following general formulas (III) to (VII): From the viewpoint of easily improving the dispersion stability of the metal particle composition, it is preferably a compound represented by at least one of general formulas (III) to (VI), and more preferably a compound represented by at least one of general formulas (III), (V), and (VI).

[0041] (However, the compound represented by general formula (III) has a weight average molecular weight (Mw) in terms of polystyrene of 200 to 50,000.)

[0042] (However, the compound represented by general formula (IV) has a weight average molecular weight (Mw) in terms of polystyrene of 200 to 50,000.)

[0043] (In general formula (V), R １０ , R １１ , R １３ and R １４ R each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. １２ represents a hydroxyl group, a (meth)acryloyloxy group, a 4-vinylphenoxy group, or an alkenyloxy group having 2 to 6 carbon atoms. １２ A and B each independently represent a substituted or unsubstituted alkylene group having 1 to 6 carbon atoms. a and b each independently represent 0 or an integer of 1 to 100.

[0044] In general formula (V), R １２ is preferably a hydroxyl group or a (meth)acryloyloxy group, more preferably a hydroxyl group. The alkenyloxy group having 2 to 6 carbon atoms may be a vinyloxy group having 2 to 6 carbon atoms. Here, the (meth)acryloyloxy group refers to an acryloyloxy group or a methacryloyloxy group.

[0045] R １２Examples of the alkenyloxy group represented by include a vinyloxy group, a 1-propenyloxy group, a 2-n-propenyloxy group (allyloxy group), a 1-n-butenyloxy group, and a prenyloxy group.

[0046] In the general formula (V), when A and B have a substituent, the substituent may be any of the above-mentioned R １２ The examples are also similar, so a duplicated explanation will be omitted.

[0047] R in general formula (V) １０ , R １１ , R １３ and R １４ Examples and preferred examples of R in the general formula (I) are １ and R ２ Since this is the same as that for (1), a duplicated explanation will be omitted.

[0048] (In general formula (VI), R １５ , R １６ , R ２１ and R ２２ R each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. １７ and R １８ R each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. １９ represents a hydrogen atom or a methyl group, R ２０ represents any one of a hydroxyl group, a (meth)acryloyloxy group, a 4-vinylphenoxy group, and an alkenyloxy group having 2 to 6 carbon atoms.

[0049] In general formula (VI), R １９ is preferably a hydrogen atom. ２０ is preferably a hydroxyl group or a (meth)acryloyloxy group, more preferably a hydroxyl group.

[0050] R in general formula (VI) １５ , R １６ , R２１ , R ２２ are R in the general formula (I), respectively. １ and R ２ and R in general formula (VI) １７ and R １８ are R in the general formula (I), respectively. ３ and R ４ and R in general formula (VI) ２０ represents R in the general formula (V). １２ The same applies to the examples and preferred aspects of these, so redundant explanations will be omitted.

[0051] The compounds represented by the general formulas (III) and (IV) each have a hydroxyl group in their molecule, and the compounds represented by the general formulas (V) and (VI) each have an electron-donating functional group R １２ and R ２０ The presence of these groups facilitates increasing the adsorption of compound (B) to metal particles while maintaining the stability of the compound. In particular, general formulas (III), (V), and (VI) have relatively highly electron-donating groups bonded to the double bonds at both ends, making it easier to improve stability.

[0052] (In general formula (VII), R ２３ , R ２４ , R ２７ and R ２８ R each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. ２５ and R ２６ each independently represents a hydrogen atom; an alkyl group having 1 to 6 carbon atoms; an alkoxy group having 1 to 6 carbon atoms; an alkenyl group having 2 to 6 carbon atoms; an aryl group; or an aralkyl group.

[0053] R in general formula (VII) ２３ , R ２４ , R ２７ and R ２８ are R in the general formula (I), respectively. １ and R２ and R in general formula (VII) ２５ and R ２６ are R in the general formula (I), respectively. ３ and R ４ The same applies to the examples and preferred aspects of these, so redundant explanations will be omitted.

[0054] Since the compound represented by general formula (VII) has an acetal structure in its molecule, the electron density around the structure is high, which tends to improve the stability of the compound.

[0055] Specific examples of the compound (B) containing the structure represented by general formula (I) include the following.

[0056]

[0057]

[0058] There is no particular limitation on the method for producing the compound (B) containing the structure represented by general formula (I), and the compound can be produced by applying known methods alone or in combination.

[0059] The metal particle composition preferably contains 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, of compound (B) containing the structure represented by general formula (I) above, per 100 parts by mass of metal particles (A). When the content of compound (B) is 0.1 parts by mass or more, sufficient dispersion stability of the metal particle composition is easily obtained. On the other hand, when the content of compound (B) is 5 parts by mass or less, the amount of metal particles (A) is relatively large, thereby ensuring the necessary amount of metal and the necessary physical properties such as conductivity, and improving the balance between production costs and the obtained effects. From this perspective, the content of compound (B) is preferably 0.1 to 4 parts by mass, more preferably 0.15 to 3 parts by mass, even more preferably 0.2 to 3 parts by mass, and even more preferably 0.2 to 2 parts by mass.

[0060] <Solvent (C)> As described above, solvent (C) is a solvent having a Hansen solubility parameter polarity term δP of 3.0 to 17.0 and a hydrogen bond term δH of 6.6 to 42.5. From the viewpoint of improving the dispersion stability of the metal particle composition, the polarity term δP is preferably 3.0 to 16.0, more preferably 3.0 to 15.0, even more preferably 3.0 to 14.0, still more preferably 3.0 to 10.0, even more preferably 3.5 to 10.0, and even more preferably 6.0 to 9.0.

[0061] From the viewpoint of improving the dispersion stability of the metal particle composition, the polarity term δH is preferably 6.6 to 35.0, more preferably 6.6 to 25.0, even more preferably 6.6 to 20.0, still more preferably 7.0 to 20.0, even more preferably 10.0 to 20.0, and still more preferably 14.0 to 17.0.

[0062] The Hansen solubility parameter (HSP value) is a three-dimensional vector obtained by dividing the solubility parameter (SP value) into three components: a dispersion term δD, a polar term δP, and a hydrogen bonding term δH. The polar term δP and the hydrogen bonding term δH of the Hansen solubility parameter can be calculated by the following calculation. That is, the calculation was performed using the calculation software "Hansen Solubility Parameters in Practice (HSPiP) Version 5.3.05" (by Steven Abbott, Charles M. Hansen, and Hiroshi Yamamoto). The method for estimating HSP values ​​in such software is based on "Hansen Solubility Parameters: A User's Handbook" (Charles M. Hansen, CRC Press, 2007) and the like.

[0063] The solvent (C) is preferably water, alcohols, ethers, ketones, or esters having a polarity parameter δP of 3.0 to 17.0 and a hydrogen bonding parameter δH of 6.6 to 42.5, more preferably water or alcohols. From the viewpoint of improving the dispersion stability of the metal particle composition, the alcohol having a polarity parameter δP of 3.0 to 17.0 and a hydrogen bonding parameter δH of 6.6 to 42.5 is preferably a monool or polyol having a polarity parameter δP of 3.0 to 17.0 and a hydrogen bonding parameter δH of 6.6 to 42.5, more preferably a monool or diol having a polarity parameter δP of 3.0 to 17.0 and a hydrogen bonding parameter δH of 6.6 to 42.5, and even more preferably a diol having a polarity parameter δP of 3.0 to 17.0 and a hydrogen bonding parameter δH of 6.6 to 42.5. From the viewpoint of improving the dispersion stability of the metal particle composition, the diol is preferably a diol in which each of the hydrogen atoms bonded to two carbon atoms in an aliphatic hydrocarbon containing one or more etheric oxygen atoms or no etheric oxygen atoms has been substituted with a hydroxyl group, more preferably a diol in which each of the hydrogen atoms bonded to two carbon atoms in an aliphatic hydrocarbon containing one or more etheric oxygen atoms has been substituted with a hydroxyl group, and even more preferably a diol in which each of the hydrogen atoms bonded to two carbon atoms in an aliphatic hydrocarbon containing one etheric oxygen atom has been substituted with a hydroxyl group. When the diol contains the etheric oxygen atom, the dispersion stability of the metal particle composition tends to be further improved.

[0064] Examples of the solvent (C) include ethylene glycol (δP: 13.5, δH: 27.4), propylene glycol (δP: 10.2, δH: 22.1), propanediol (δP: 11.7, δH: 23.7), dipropylene glycol (δP: 8.2, δH: 15.5), glycerin (δP: 12.7, δH: 27.8), butyl carbitol (δP: 6.2, δH: 10.5), ethylene glycol monobutyl ether (δP: 6.3, δH: 12.3), 3-methyl-1,3-butanediol (δP: 11.0, δH: 22.8), 3-methoxy-3-methyl-1-butanol (δP: 6.0, δH: 9.9), nonanediol (δP: 6.5, δH: 1 3.8), 2-methyl-1,8-octanediol (δP: 6.3, δH: 13.9), α-terpineol (δP: 3.6, δH: 7.7), water (δP: 16.0, δH: 42.0) are preferred, ethylene glycol (δP: 13.5, δH: 27.4), dipropylene glycol (δP: 8.2, δH: 15.5), α-terpineol (δP: 3.6, δH: 7.7), water (δP: 16.0, δH: 42.0) are more preferred, dipropylene glycol (δP: 8.2, δH: 15.5) and α-terpineol (δP: 3.6, δH: 7.7) are even more preferred, and dipropylene glycol (δP: 8.2, δH: 15.5) is even more preferred.

[0065] Solvent (C) can be used as a mixed solvent if the polarity parameter δP of the mixed solvent after mixing two or more solvents is in the range of 3.0 to 17.0 and the hydrogen bonding parameter δH is in the range of 6.6 to 42.5. Here, the polarity parameter δP and the hydrogen bonding parameter δH of the Hansen solubility parameter in the mixed solvent can be calculated as a weighted average of the polarity parameter δP and the hydrogen bonding parameter δH of each solvent contained in the mixed solvent and the volume fraction of each solvent contained in the mixed solvent.

[0066] The metal particle composition preferably contains 10 to 100,000 parts by mass of solvent (C) relative to 100 parts by mass of the total amount of metal particles (A) and compound (B). When the content of solvent (C) is 10 parts by mass or more, the metal particle composition does not solidify and can maintain a paste state. On the other hand, when the content of solvent (C) is 100,000 parts by mass or less, the amount of metal particles (A) is relatively large, thereby ensuring the necessary amount of metal and the necessary physical properties such as conductivity. From this perspective, the content of solvent (C) is preferably 50 to 80,000 parts by mass, more preferably 100 to 50,000 parts by mass, even more preferably 500 to 20,000 parts by mass, and even more preferably 1,000 to 15,000 parts by mass. Furthermore, the content of solvent (C) is also preferably 10 to 20,000 parts by mass. The metal particle composition may contain a solvent other than solvent (C). From the viewpoint of improving the dispersion stability of the metal particle composition, the content of solvent (C) in the total amount of solvent is preferably 60 to 100 mass%, more preferably 80 to 100 mass%, even more preferably 90 to 100 mass%, and even more preferably 100 mass%.

[0067] <Other Components> The metal particle composition may further contain components other than those described above, such as a diluent, pigment, dye, filler, UV absorber, thickener, shrinkage reducing agent, antioxidant, plasticizer, aggregate, flame retardant, stabilizer, fiber reinforcement, antioxidant, leveling agent, and anti-sagging agent. A paste containing the metal particle composition will be described later. From the viewpoint of improving the dispersion stability of the metal particle composition, the total amount of the metal particles (A), compound (B), and solvent (C) in the metal particle composition is preferably 60% by mass or more, preferably 60 to 100% by mass, more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass, and even more preferably 100% by mass.

[0068] [Method for Producing a Metal Particle Composition] A method for producing a metal particle composition according to an embodiment of the present invention includes a mixing step of mixing metal particles (A), a compound (B), and a solvent (C). This allows the production of a metal particle composition. The method for producing a metal particle composition may include a step of coating metal particles (A) with a compound (B) having a structure represented by general formula (I) above, and a dispersion step of mixing the metal particles (A) coated with compound (B) with a solvent (C) having a Hansen solubility parameter polarity term δP of 3.0 to 17.0 and a hydrogen bonding term δH of 6.6 to 42.5.

[0069] <Mixing Step> In the mixing step, there is no particular limitation on the order in which the components are mixed. That is, there is no particular limitation on the order in which the metal particles (A), the compound (B), and the solvent (C) are mixed. All of the components may be mixed at once or sequentially. In the method for producing a metal particle composition, from the viewpoint of facilitating uniform mixing of the metal particles (A) and the compound (B), it is also preferable to mix the metal particles (A) and the compound (B) in the mixing step and then mix the solvent (C). From the same viewpoint, it is also preferable to mix the metal particles (A), the compound (B), and the organic solvent in the mixing step and then mix the solvent (C). In this case, it is more preferable to mix the metal particles (A), the compound (B), and the organic solvent, remove the organic solvent, and then mix the solvent (C). It is preferable that the method further includes a coated metal particle production step in which the metal particles (A), the compound (B), and the organic solvent are mixed and the organic solvent is removed to obtain coated metal particles, and a dispersion step in which the coated metal particles are mixed with the solvent (C) to obtain a dispersion.

[0070] <Coated Metal Particle Production Process> In the coated metal particle production process, the order in which the components are mixed is not particularly limited. Compound (B) may be mixed into an organic solvent and then metal particles (A) may be added. Alternatively, metal particles (A) may be mixed into an organic solvent and then compound (B) may be added. Alternatively, compound (B) and metal particles (A) may be added simultaneously to the organic solvent. Other components used as needed may be mixed together with metal particles (A) and compound (B). The order in which the other components are added is not particularly limited. Other components may be added to the organic solvent together with compound (B), or may be added to the organic solvent together with metal particles (A), or may be added to the organic solvent together with compound (B) and metal particles (A). The amount of compound (B) added per 100 parts by mass of metal particles (A) is preferably 10 to 500 parts by mass, more preferably 20 to 200 parts by mass, from the viewpoint of obtaining a metal particle composition having the composition described above.

[0071] Next, the organic solvent is removed to obtain coated metal particles. More specifically, the organic solvent is removed from the mixture by distilling it off using an evaporator or the like, thereby obtaining coated metal particles consisting of metal particles (A) and a compound (B) coating the metal particles (A). More preferably, the coated metal particles include a coating layer on the surface of the metal particles (A), and the coating layer includes the compound (B). In the coated metal particles, the coating layer may contain components other than the compound (B) in addition to the compound (B). However, from the viewpoint of improving the volatility of the coating layer, it is preferable that the main component of the coating layer is the compound (B), more preferably 90 mass% or more of the coating layer is the compound (B), and even more preferably the coating layer is substantially composed only of the compound (B). From the viewpoint of improving the volatility of the coating layer, it is preferable that the coating layer does not contain a resin component. Furthermore, the coating layer may coat the entire metal particles (A), or may coat only a portion of the metal particles (A). Alternatively, the compound (B) may adhere to the metal particles (A). Examples of organic solvents used in the production of coated metal particles include acetone, methanol, 1-propanol, and tetrahydrofuran. The amount of organic solvent used is not particularly limited, but is, for example, 0.2 to 2.0 L per 10 g of compound (B). In the process for producing coated metal particles, the above-mentioned organic solvents can be used as the metal particles (A). When a metal compound (such as a metal oxide) containing a metal element and an element other than the metal element is used as the raw material for the metal particles (A), the metal compound may be converted into a metal in this process. For example, when a metal oxide is used as the raw material for the metal particles (A), a reducing agent such as hydrazine monohydrate may be further added to reduce the metal oxide and convert it into a metal.

[0072] <Dispersion Step> In the dispersion step, the coated metal particles and the solvent (C) are mixed. The solvent (C) can be any of those described above. The mixing method is not particularly limited, but stirring and mixing may be performed using an ultrasonic homogenizer, roll mill, ball mill, bead mill, paint shaker, kneader, attritor, sand mill, etc. By mixing the coated metal particles and the solvent (C), a metal particle composition can be obtained.

[0073] [Uses of Metal Particle Composition] The metal particle composition has excellent oxidation resistance, does not require a transition metal catalyst, and is applicable to existing metal particles. Therefore, it can be used in a wide range of fields. For example, it can be used as a raw material powder for powder metallurgy, a firing paste for multilayer ceramic capacitors, or a material for a conductive paste or conductive ink for forming wiring by inkjet printing or the like.

[0074] [Paste] A paste according to an embodiment of the present invention includes the metal particle composition. As described above, the metal particle composition has excellent dispersion stability, so that a paste can be obtained that is less likely to cause problems such as increased electrical resistance or decreased thermal conductivity even if the particle size of the metal particles (A) is small. As described above, the paste is less likely to cause problems such as increased electrical resistance or decreased thermal conductivity even if the particle size of the metal particles (A) is small, so it can be used, for example, as a conductive paste for forming wiring in electronic components or a firing paste for multilayer ceramic capacitors.

[0075] The paste may further contain a binder. Examples of binders include those containing a resin and a solvent. When the paste contains a binder, it can be given the function of adhering and solidifying the metal particles (A) to an object such as a printed wiring board. The resin contained in the binder is preferably a thermosetting resin or an ultraviolet-curing resin. It may also be a resin that is cured by other energy rays such as an electron beam. For example, when the resin is a thermosetting resin, the paste can be solidified by heating. When the resin is an ultraviolet-curing resin, the paste can be solidified by irradiating the paste with ultraviolet light.

[0076] The thermosetting resin is not particularly limited, but examples thereof include various modified polyester resins such as polyester resin, urethane-modified polyester resin, epoxy-modified polyester resin, and acrylic-modified polyester resin, polyurethane resin, polyetherurethane resin, polycarbonateurethane resin, acrylicurethane resin, vinyl chloride-vinyl acetate copolymer, epoxy resin, modified epoxy resin, phenol resin, acrylic resin, alkyd resin, alkydphenol resin, butyral resin, polyvinyl butyral resin, ethylene-vinyl acetate copolymer, polyamideimide, polyimide, polyamide, nitrocellulose, modified cellulose such as cellulose acetate butyrate and cellulose acetate propionate, etc. These may be used alone or in combination of two or more. A thermal polymerization catalyst such as peroxide may be used in combination with the thermosetting resin.

[0077] The UV-curable resin can be a resin obtained using a photopolymerizable monomer. That is, the UV-curable resin is obtained by polymerizing the photopolymerizable monomer. The photopolymerizable monomer is not particularly limited, but examples thereof include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polyurethane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, trimethylolpropane ethylene oxide-modified tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. These may be used alone or in combination of two or more. Furthermore, a photopolymerization initiator, a photosensitizer, or the like may be used in combination with the UV-curable resin.

[0078] The solvent contained in the binder functions to mix the metal particles (A) with the resin. This solvent may be different from or the same as the solvent (C). The solvent is volatilized and removed when the paste is adhered to and solidified on an object such as a printed wiring board.

[0079] The solvent is not particularly limited as long as it is inert, and examples thereof include aromatics such as anisole and diphenyl ether, glycol ethers such as cellosolve, methyl cellosolve, carbitol, methyl carbitol, butyl carbitol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and tripropylene glycol normal butyl ether, esters such as ethyl acetate, butyl acetate, ethyl butyrate, n-butyl butyrate, and cellosolve acetate, alcohols such as ethanol, propanol, ethylene glycol, propylene glycol, terpineol, and butyl carbitol, and esters of these higher alcohols with carboxylic acids. These may be used alone or in combination of two or more.

[0080] From the viewpoint of electrical conductivity and adhesiveness, the content of the binder in the paste is preferably 10 to 50 parts by mass, more preferably 12.5 to 33.3 parts by mass, per 100 parts by mass of the metal particles (A).

[0081] From the viewpoint of ease of handling, the viscosity of the paste at 25°C is preferably 10 to 200,000 mPa·s, more preferably 1,000 to 100,000 mPa·s. The viscosity can be measured, for example, using a cone-plate viscometer. When the paste is applied to an object by spraying from a nozzle such as an inkjet nozzle, the paste may be further diluted with an organic solvent or the like.

[0082] The thixotropy ratio of the paste at 25°C is preferably 1.0 to 4.0, more preferably 1.5 to 3.5, from the viewpoint of ease of handling. Here, the thixotropy ratio at 25°C is the thixotropy ratio at a shear rate of 10 s －１ Viscosity at 100 s / shear rate at 25 ° C. －１ The viscosity at

[0083] The shape of the metal particles (A) contained in the paste is not particularly limited, and can be various shapes as described above, but is particularly preferably spherical. When the metal particles (A) contained in the paste are spherical, the fluidity is improved, so when a paste containing spherical metal particles is sprayed onto an object from a nozzle such as an inkjet head, clogging of the nozzle is easily suppressed, and ultimately, a conductive circuit of a printed wiring board or the like can be easily formed at a desired position.

[0084] The paste may further contain various components listed as other components that may be contained in the metal particle composition. The paste may also contain a conductive organic compound. Examples of the conductive organic compound include conjugated organic compounds having electrical conductivity, such as polycyclic aromatic compounds such as pentacene, conductive polymers such as polyacetylene, poly(p-phenylene vinylene), polypyrrole, polythiophene, polyaniline, poly(p-phenylene sulfide), and polyphenylene vinylene, and conductive liquid crystals. Among these, conductive liquid crystals are preferred from the viewpoint of further improving electrical conductivity, and a mixture of two or more types of conductive liquid crystals is more preferred. The conductive liquid crystals further improve the electrical conductivity of the paste by regularly aligning themselves between the metal particles.

[0085] The method for producing the paste is not particularly limited, and various conventionally known production methods can be used. For example, the paste can be produced by mixing the metal particle composition, the binder, and other components used as needed by a known method.

[0086] After the paste is applied to an object such as a printed wiring board, it is heated, for example, at 100°C or higher, to volatilize the solvent in the binder and, if the resin in the binder is a thermosetting resin, harden it. If the resin in the binder is an ultraviolet-curable resin, it is hardened by irradiating it with ultraviolet light after or in addition to heating. When the paste is solidified in this way, it can be adhered to and solidified on the printed wiring board or the like in a uniformly dispersed state while maintaining a state in which adjacent metal particles are in contact with each other or a state in which adjacent metal particles are connected to each other via a conductive organic compound.

[0087] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples.

[0088] The metal particle compositions obtained in the examples and comparative examples were evaluated as follows. <Evaluation of dispersion stability> A vial containing a dispersion of metal particles was left to stand at room temperature, and the degree of sedimentation was observed. The number of days until the interface between the metal particles and the supernatant liquid became less than half the liquid height was recorded as the "number of days required for sedimentation."

[0089] <Average particle size> The average particle size was calculated based on JIS H 7804: 2005. A photograph of the sample was taken using a scanning electron microscope (SEM, JSM-6701F manufactured by JEOL Ltd., acceleration voltage 15 kV), and the particle sizes of 100 particles were measured from five representative fields of view randomly selected, and the arithmetic mean was taken as the average particle size of the metal particles.

[0090] <TG Measurement (Thermogravimetry)> TG measurement (thermogravimetry) was performed under the following measurement conditions. Measuring instrument: DTG-60H (Shimadzu Corporation) Measurement temperature: Cooling conditions included cooling at -5°C / min and holding at a temperature of 20°C for 100 minutes. Heating conditions included a heating rate of 5°C / min and a temperature of 600°C for 0 minutes. Sample amount: Approximately 10 mg Cell: Alumina Atmospheric gas: Nitrogen Gas flow rate: 100 ml / min

[0091] The raw materials and compounds used in the examples and comparative examples are as follows: <Metal particles (A)> Silver particles (A-1): NP-AG-1-25 (manufactured by EM Japan Co., Ltd., average particle size: 40 nm) CuO particles (A-2): manufactured by Nissin Chemco Co., Ltd., average particle size: 2.4 μm

[0092] <Compound (B)> Compound (B-1): 1,3-bis(3-methyl-2-butenoxy)-2-hydroxypropane (DPNG) Compound (B-2): glycerol α,α'-diallyl ether (DAGE) (manufactured by Tokyo Chemical Industry Co., Ltd.) <Compound (B')> Compound (B'-1): hexanoic acid (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0093] <Solvent (C)> Solvent (C-1): Ethylene glycol (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) (δP: 13.45, δH: 27.35) Solvent (C-2): Dipropylene glycol (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) (δP: 8.15, δH: 15.48) Solvent (C-3): Water (δP: 15.97, δH: 41.98) Solvent (C-4): α-Terpineol (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) (δP: 3.58, δH: 7.66) <Solvent (C')> Solvent (C'-1): Turpentine oil (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) (δP: 1.05, δH: 2.02) Solvent (C'-2): Acetone (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) (δP: 9.10, δH: 6.53)

[0094]

[0095] Synthesis Example 1 Synthesis of Compound (B-1) A reactor equipped with a stirrer, a thermometer, and a dropping funnel was charged with 61.8 g (0.717 mol, manufactured by Kuraray Co., Ltd.) of 3-methyl-2-buten-1-ol and 36.84 g (0.657 mol) of potassium hydroxide under a nitrogen stream. The internal temperature was maintained at 10°C or below, and 19.34 g (0.209 mol, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) of epichlorohydrin was added dropwise with stirring. After completion of the dropwise addition, the temperature was raised to 50°C. The mixture was stirred at an internal temperature of 50°C for 6 hours and then cooled to 25°C. The reaction solution was neutralized with a 4 M aqueous hydrochloric acid solution, and the upper layer was washed with 310 mL of ion-exchanged water. The resulting organic layer was purified by distillation to obtain 28.77 g (0.126 mol; yield 60.3%) of 1,3-bis(3-methyl-2-butenoxy)-2-hydroxypropane represented by the following formula (B-1).

[0096] <Production Example 1> 500 mg of silver particles (A-1), 500 mg of compound (B-1), and 50 mL of methanol were placed in a beaker and subjected to ultrasonic irradiation for 10 minutes using an ultrasonic homogenizer. The resulting silver particle dispersion was centrifuged to remove the supernatant, and the particles were then washed with methanol and acetone and vacuum dried to obtain 420 mg of coated silver particles coated with compound (B-1). The amount of compound (B-1) coated on the coated silver particles was determined from the weight loss measured by TG measurement (sample amount: 13.630 mg) under a nitrogen stream. The blending amounts of each component, and the contents of silver particles (A-1) and compound (B-1) in the resulting coated silver particles are shown in Table 1.

[0097] <Production Example 2 and Comparative Production Example 1> Coated silver particles were obtained in the same manner as in Production Example 1, except that the blending amounts of each component were as shown in Table 1. The amount of coating of compound (B) or (B') was measured from the amount of weight loss by TG measurement under a nitrogen stream. The contents of silver particles (A-1) and compound (B) or (B') in the obtained coated silver particles are shown in Table 1.

[0098]

[0099] Example 1 250 mg of the coated silver particles obtained in Production Example 1 ((A-1) silver particles:(B-1) DPNG=98.94:1.06 (mass ratio)) and 25 g of (C-1) ethylene glycol were placed in a beaker and subjected to ultrasonic irradiation for 5 minutes using an ultrasonic homogenizer, yielding a silver particle dispersion. The resulting dispersion was allowed to stand, and its dispersion stability was evaluated. The contents of each component in the silver particle dispersion and the results of the evaluation of dispersion stability are shown in Table 2.

[0100] Examples 2 to 8, Comparative Examples 1 to 10 Silver particle dispersions were obtained in the same manner as in Example 1, except for the formulations shown in Table 2. The resulting dispersions were allowed to stand, and the dispersion stability was evaluated. The contents of each component in the silver particle dispersions and the evaluation results of dispersion stability are shown in Table 2.

[0101]

[0102] As is clear from the results in Table 2, the metal particle composition of the present invention containing compound (B) has higher dispersion stability than the comparative example not containing compound (B). Furthermore, high dispersion stability was exhibited in solvents whose Hansen solubility parameters for solvent (C) were within a specified range, whereas sedimentation was observed within one day in solvents outside the range, and dispersion stability was not maintained.

[0103] <Production Example 3> A reactor equipped with a stirrer and a thermometer was charged with 50 mL of 1-propanol, 3.98 g of CuO particles (A-2) (manufactured by Nisshin Chemco Co., Ltd., average particle size 2.4 μm), and 1.6 g of compound (B-1). The internal temperature was raised to 70°C, and 6.0 g of hydrazine monohydrate was added with stirring, followed by stirring for 1 hour. After cooling to room temperature, the supernatant was removed by centrifugation, and the copper particles were washed with 1-propanol and acetone and vacuum dried to obtain 3.0 g of copper particles whose surfaces were coated with compound (B-1). The average particle diameter determined by measurement with a scanning electron microscope was 100 nm. The coating amount of compound (B-1) was measured from the weight loss by TG measurement under a nitrogen stream.

[0104]

[0105] Example 9 250 mg of the coated copper particles obtained in Production Example 3 ((A-2) copper particles:(B-1) DPNG=98.2:1.8 (mass ratio)) and 25 g (100 parts by mass) of (C-1) ethylene glycol were placed in a beaker and subjected to ultrasonic irradiation for 5 minutes using an ultrasonic homogenizer, thereby obtaining a copper particle dispersion. The obtained dispersion was allowed to stand, and its dispersion stability was evaluated. The contents of each component in the copper particle dispersion and the evaluation results of dispersion stability are shown in Table 4.

[0106] Comparative Example 11 A copper particle dispersion was obtained in the same manner as in Example 9, except that the compound (B-1) and the solvent (C-1) were used in the proportions shown in Table 4. The obtained dispersion was allowed to stand, and the dispersion stability was evaluated. The contents of each component in the copper particle dispersion and the evaluation results of the dispersion stability are shown in Table 4.

[0107]

[0108] As is clear from the results in Table 4, even if the metal particles (A) are copper particles, they exhibit high dispersion stability.

Claims

1. A metal particle composition comprising: metal particles (A); a compound (B) having a structure represented by the following general formula (I); and a solvent (C) having a Hansen solubility parameter polarity term δP of 3.0 to 17.0 and a hydrogen bond term δH of 6.6 to 42.

5. (In general formula (I), R １ and R ２ R each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. ３ and R ４ each independently represents a hydrogen atom; an alkyl group having 1 to 6 carbon atoms; an alkoxy group having 1 to 6 carbon atoms; an alkenyl group having 2 to 6 carbon atoms; an alkenyloxy group having 2 to 6 carbon atoms; an aryl group; or an aralkyl group.

2. The metal particle composition according to claim 1, wherein the compound (B) containing the structure represented by general formula (I) is a compound containing a structure represented by the following general formula (II): (In general formula (II), R ５ and R ６ R each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. ７ and R ８ R each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkenyloxy group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. ９ represents a hydrogen atom; a (meth)acrylic group; an alkyl group having 1 to 6 carbon atoms; an alkenyl group having 2 to 6 carbon atoms; an aryl group; or an aralkyl group.

3. The metal particle composition according to claim 1 or 2, wherein the metal particles (A) are particles of at least one metal selected from the group consisting of silver and copper.

4. The metal particle composition according to any one of claims 1 to 3, wherein the solvent (C) comprises at least one selected from the group consisting of water and alcohols.

5. The metal particle composition according to any one of claims 1 to 4, wherein the solvent (C) comprises at least one selected from the group consisting of water, ethylene glycol, dipropylene glycol, 3-methyl-1,3-butanediol, 3-methoxy-3-methyl-1-butanol, and α-terpineol.

6. The metal particle composition according to any one of claims 1 to 5, wherein the content of the compound (B) is 0.1 to 10 parts by mass per 100 parts by mass of the metal particles (A).

7. The metal particle composition according to any one of claims 1 to 6, wherein the content of the solvent (C) is 10 to 20,000 parts by mass per 100 parts by mass of the metal particles (A).

8. A method for producing a metal particle composition comprising metal particles (A), a compound (B) having a structure represented by general formula (I), and a solvent (C) having a Hansen solubility parameter polarity term δP of 3.0 to 17.0 and a hydrogen bond term δH of 6.6 to 42.5, the method comprising a mixing step of mixing the metal particles (A), the compound (B), and the solvent (C). (In general formula (I), R １ and R ２ R each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an aryl group, or an aralkyl group. ３ and R ４ each independently represents a hydrogen atom; an alkyl group having 1 to 6 carbon atoms; an alkoxy group having 1 to 6 carbon atoms; an alkenyl group having 2 to 6 carbon atoms; an alkenyloxy group having 2 to 6 carbon atoms; an aryl group; or an aralkyl group.

9. The method for producing a metal particle composition according to claim 8, wherein in the mixing step, the metal particles (A) and the compound (B) are mixed together, and then mixed with the solvent (C).

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