Plating solution additives

Abstract

To provide a plating solution additive having excellent dispersibility in water, eliminating the needs of special preprocessing and reaction because nanocarbon can be co-deposited only by entering a plating solution, and capable of efficiently co-depositing nanocarbon in small amounts.SOLUTION: A plating solution additive contains a flaky carbon whose thickness is 1 to 100 nm and an organic compound including a hydrophobic group with a high affinity between a hydrophilic group and carbon. The plating solution additive contains 0.1 to 100 pts.mass of an organic component including a hydrophobic group with a high affinity between a hydrophilic group and carbon to 1 pt.mass of the flaky carbon.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a plating solution additive. [Background technology]

[0002] The addition of solid particles (fillers) to plating is often used to enhance its functionality. For example, the addition of polytetrafluoroethylene (PTFE), a fluororesin, to nickel plating can provide it with sliding properties and water repellency.

[0003] In this case, problems may arise such as poor dispersibility of the filler in water, inefficient co-deposition resulting in the need to add a large amount of filler, and inability to co-deposit the filler uniformly.

[0004] In particular, when nanocarbon is added as a filler, it is expected to improve thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, etc., but nanocarbon has poor affinity with water and tends to aggregate with other nanocarbons, making the above problems more likely to occur.

[0005] For this reason, in Non-Patent Documents 1 and 2, carbon nanotubes are treated with an acid such as nitric acid or sulfuric acid. This method aims to solve the above problem by hydrophilizing the surface of the hydrophobic carbon nanotubes, but it has poor production efficiency and generates NOx when heated, making mass production difficult. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] IOP Conference Series: Materials Science and Engineering. Vol. 438, No. 1, 012003, 2018. [Non-patent document 2] Journal of Nanomaterials 2011, 6348 (2011). Summary of the Invention [Problem to be solved by the invention]

[0007] As mentioned above, nanocarbon is expected to improve thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, etc. However, nanocarbon has poor affinity with water and tends to aggregate with other nanocarbons, which can lead to problems such as poor dispersibility of nanocarbon in water, the need to add a large amount of nanocarbon without efficient co-deposition, and the inability to co-deposit nanocarbon uniformly.

[0008] Therefore, the present invention aims to provide a plating solution additive that has excellent dispersibility in water, can codeposit nanocarbon simply by adding it to the plating solution, does not require any special pretreatment or reaction, and can codeposit nanocarbon efficiently during plating with a small amount. [Means for solving the problem]

[0009] As a result of extensive research to achieve the above-mentioned object, the present inventors have found that by incorporating a predetermined amount of flaky carbon having a thickness of 1 to 100 nm and an organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon, a plating solution additive can be obtained that has excellent dispersibility in water, can codeposit nanocarbon simply by adding it to the plating solution, does not require special pretreatment or reaction, and can efficiently codeposit nanocarbon during plating in small amounts. Based on this finding, the present inventors have conducted further research and have completed the present invention. Specifically, the present invention encompasses the following features.

[0010] Item 1. A carbon fiber composite material comprising a flaky carbon fiber having a thickness of 1 to 100 nm and an organic compound having a hydrophilic group and a hydrophobic group having a high affinity with carbon; The plating solution additive contains 0.1 to 100 parts by mass of an organic compound having a hydrophilic group and a hydrophobic group having high affinity for carbon, per part by mass of the flaky carbon.

[0011] Item 2. The hydrophilic group has general formulas (1) to (4):

[0012] [ka]

[0013] [In the formula, -OH represents an alcoholic hydroxyl group or a phenolic hydroxyl group. R represents a divalent organic group. X1 represents a hydrogen atom, an alkali metal, NH4, or an organic ammonium. X2 represents a hydrogen atom, an alkali metal, NH4, an organic ammonium, or an alkyl group. The oxygen atom in general formula (2) is an ether bond.] Item 1. The plating solution additive according to item 1, wherein the additive is at least one of the following:

[0014] Item 3. The plating solution additive according to Item 1 or 2, wherein the hydrophilic group is a phenolic hydroxyl group and / or a polyoxyethylene group.

[0015] Item 4. The plating solution additive according to any one of Items 1 to 3, wherein the hydrophobic group is at least one selected from the group consisting of an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, and a polyoxyalkylene group having 3 or more carbon atoms.

[0016] Item 5. The plating solution additive according to any one of Items 1 to 4, wherein the hydrophobic group is an aryl group having two or more aromatic rings.

[0017] Item 6. The plating solution additive according to any one of Items 1 to 5, wherein the organic compound having a hydrophilic group and a hydrophobic group having high affinity for carbon is polyoxyethylene naphthyl ether and / or a plant polyphenol.

[0018] Item 7. The plating solution additive according to Item 6, wherein the plant polyphenol is at least one selected from the group consisting of persimmon tannin, tannic acid, catechin, anthocyanin, isoflavone, chlorogenic acid, ellagic acid, curcumin, and caffeic acid.

[0019] Item 8. The plating solution additive according to any one of Items 1 to 7, which is a dispersion in a solvent containing water.

[0020] Item 9. The plating solution additive according to Item 8, wherein the content of the water is 25% by mass or more, based on 100% by mass of the total amount of the plating solution additive.

[0021] Item 10. The plating solution additive according to any one of items 1 to 9, A plating solution containing at least one metal compound selected from the group consisting of nickel compounds, copper compounds, zinc compounds, chromium compounds, tin compounds, silver compounds, and gold compounds.

[0022] Item 11. The plating solution according to Item 10, wherein the flaky carbon is contained in an amount of 0.001 to 5% by mass, with the total amount of the plating solution being 100% by mass.

[0023] Item 12. The plating solution according to Item 10 or 11, wherein the organic compound having a hydrophilic group and a hydrophobic group having high affinity for carbon is contained in an amount of 0.001 to 10 mass % relative to 100 mass % of the total amount of the plating solution.

[0024] Item 13. A method for producing the plating solution according to any one of items 10 to 12, a step of mixing the solution containing the metal compound with the plating solution additive; A manufacturing method comprising:

[0025] Item 14. A thin plated film comprising the plating solution additive according to any one of items 1 to 9 and at least one metal selected from the group consisting of nickel, copper, zinc, chromium, tin, silver, and gold.

[0026] Item 15. An electrolytic plating method, Item 10 to 12. The plating solution according to any one of items 10 to 12 is used, and the plating current is 5 A / dm 2 Electroplating method, wherein a current density of less than [Effects of the Invention]

[0027] According to the present invention, a plating solution additive can be provided that has excellent dispersibility in water, and can codeposit nanocarbon simply by adding it to the plating solution, eliminating the need for special pretreatment or reaction, and that can efficiently codeposit nanocarbon during plating with a small amount. [Brief explanation of the drawings]

[0028] [Figure 1] The composition of the plating solution additive of the present invention is shown below when the content of the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon is low (when the surface of the flaky carbon is coated with an organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon). [Figure 2] The composition of the plating solution additive of the present invention is shown below when the content of the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon is high (when flaky carbon is dispersed in the organic compound having a hydrophobic group having a high affinity for carbon). [Figure 3] 1 is a scanning electron microscope (SEM) image of the surface of the nickel plating obtained in Example 1. [Figure 4] 1 is a scanning electron microscope (SEM) image of the surface of the nickel plating obtained in Example 2. [Figure 5] 1 is a scanning electron microscope (SEM) image of the surface of the copper plating obtained in Example 3. [Figure 6] 1 is a scanning electron microscope (SEM) image of the surface of the copper plating obtained in Example 4. [Figure 7] 1 is a scanning electron microscope (SEM) image of the surface of the copper plating obtained in Example 5. [Figure 8] 1 is a photograph of the appearance of the nickel plating solution obtained in Comparative Example 2, 20 hours after production. [Figure 9] 1 shows the results of measuring the dynamic friction coefficient in Experimental Example 1 using the copper plating obtained in Example 2. [Figure 10] 1 shows the results of measuring the dynamic friction coefficient in Experimental Example 1 using the nickel plating obtained in Comparative Example 1. [Figure 11] 1 shows the results of measuring the dynamic friction coefficient in Experimental Example 2 using the nickel plating obtained in Example 1. [Figure 12] 1 shows the results of measuring the dynamic friction coefficient in Experimental Example 2 using the nickel plating obtained in Example 2. [Figure 13] 1 shows the results of measuring the dynamic friction coefficient in Experimental Example 2 using the nickel plating obtained in Comparative Example 1. [Figure 14] 10 shows the results of measuring the dynamic friction coefficient in Experimental Example 3 using the copper plating obtained in Example 4. [Figure 15] 10 shows the results of measuring the dynamic friction coefficient in Experimental Example 3 using the copper plating obtained in Example 5. [Figure 16] 10 shows the results of measuring the dynamic friction coefficient in Experimental Example 3 using the copper plating obtained in Comparative Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0029] In this specification, the term "containing" is a concept that encompasses all of "comprise," "consist essentially of," and "consist only of."

[0030] In addition, in this specification, when a numerical range is expressed as "A to B," it means A or more and B or less.

[0031] Although the embodiments of the present invention will be described below, various modifications of the form and details are possible without departing from the spirit and scope of the claims.

[0032] 1. Plating solution additives The plating solution additive of the present invention contains flaky carbon having a thickness of 1 to 100 nm and an organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon, and contains 0.01 to 10 parts by mass of the organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon per part by mass of the flaky carbon.

[0033] (1-1) Flake carbon The flaky carbon functions as a heat conductor, an electric conductor, a lubricant, a friction reducer, an abrasion resistant material, a gas barrier material, a corrosion resistant material, a strength improver, and the like.

[0034] Thinner flaky carbon is preferable because it has better thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, and strength, and can be made into lightweight, easily processable forms such as thin sheets or coatings. The thickness is 1 to 100 nm, preferably 1 to 20 nm. For the same reason, the content of flaky carbon having a thickness of 1 to 10 nm is preferably 80% or more, and more preferably 90% or more, based on the total number of flaky carbons being 100%. In other words, thicker flaky carbons may be included, but the thickness of the majority of the flaky carbons is preferably 10 nm or less. The thickness of the flaky carbons is measured by observation with a transmission electron microscope (TEM).

[0035] Thinner flaky carbon is preferable because it has excellent thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, and strength, and can be formed into lightweight, easily processable forms such as thin sheets or coatings. However, flaky carbon having a layered structure with 300 or fewer graphene layers (i.e., 1 to 300 layers) is preferred, with flaky carbon having a layered structure with 1 to 60 graphene layers being more preferred. For the same reasons, the content of flaky carbon having 1 to 30 layers is preferably 80% or more, and more preferably 90% or more, of the total number of flaky carbons taken as 100%. In other words, while thicker flaky carbons may be included, the thickness of the majority of the flaky carbons is preferably 30 layers or less. The thickness of the flaky carbons is calculated from the thickness measured by transmission electron microscope (TEM) observation.

[0036] Since flake carbon usually has a planar shape with many convex and concave angles, it is difficult to define its size in general terms other than thickness. In this specification, the size of a piece of flake carbon is defined as the distance between the furthest convex angles in that piece of flake carbon.

[0037] The size of such flaky carbon is preferably 20 nm or more, more preferably 100 nm or more, and even more preferably 200 nm or more. Using flaky carbon of such a size provides excellent thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, etc., and facilitates the formation of lightweight, easily processable forms such as thin sheets or coating films. The larger the size of the flaky carbon, the better the thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, lightness, processability, etc. However, from the viewpoint of being less likely to aggregate in the plating solution and less likely to cause unevenness in the plating film, the size of the flaky carbon is preferably 100 μm or less, more preferably 10 μm or less. The size of the flaky carbon is measured by observation with a transmission electron microscope (TEM).

[0038] In the plating solution additive of the present invention, the content of flaky carbon is not particularly limited, but from the viewpoints of thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, dispersibility in water (resistance to aggregation), etc., the content is preferably 0.1 to 75.0 mass%, and more preferably 1.0 to 66.0 mass%, relative to 100 mass% of the total amount of the plating solution additive of the present invention.

[0039] (1-2) Organic compounds with hydrophilic groups and hydrophobic groups with high affinity for carbon In the present invention, by using an organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon, the flaky carbon that maintains the graphene structure does not aggregate, and the flaky carbon can be maintained in a uniformly dispersed state in the plating solution additive of the present invention. As a result, the flaky carbon can be efficiently codeposited with the metal during plating with a small amount and without pretreatment or reaction. The organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon can also function as a dispersant for uniformly dispersing the flaky carbon.

[0040] The organic compound having such a hydrophilic group and a hydrophobic group that has a high affinity for carbon is not particularly limited, and a wide variety of organic compounds (especially water-soluble compounds) that can function as a dispersant for flaky carbon can be used.

[0041] Among these, the hydrophobic group contained in the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon is not particularly limited, but an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, a polyoxyalkylene group having 3 or more carbon atoms, etc. are preferred. The organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon can contain one or more types of such hydrophobic groups. Furthermore, when multiple hydrophobic groups are used, multiple same hydrophobic groups may be used, or multiple same hydrophobic groups or multiple different hydrophobic groups may be used.

[0042] The alkyl group may be a chain alkyl group or a branched chain alkyl group, but from the viewpoint of affinity with carbon, a chain alkyl group is preferred. From the viewpoint of affinity with carbon, the number of carbon atoms in the alkyl group is preferably 6 or more, more preferably 8 to 28, and even more preferably 10 to 22. Examples of such an alkyl group include a hexyl group, an octyl group, a decyl group, an undecyl group, a dodecyl group (or a lauryl group), a tridecyl group, a tetradecyl group (or a myristyl group), a pentadecyl group, a hexadecyl group (or a cetyl group), an octadecyl group, and an icosyl group.

[0043] The alkyl group may or may not have a substituent. Examples of such a substituent include a cycloalkyl group, an aryl group, and an aralkyl group. Examples of the cycloalkyl group and the aryl group are described below.

[0044] The aralkyl group as a substituent of the alkyl group is preferably an aralkyl group having 7 to 14 carbon atoms and an aryl group described below and an alkyl group having 1 to 6 carbon atoms, specifically, a benzyl group, a phenethyl group, etc. are preferred.

[0045] The substituent is not limited to the above, and may have a group derived from a fluorene structure (such as a fluorenyl group). In particular, when importance is placed on water solubility, a phenyl group or the like is preferred as the substituent, and when importance is placed on compatibility with the flaky carbon, a naphthyl group, a fluorenyl group or the like is preferred as the substituent.

[0046] From the viewpoints of affinity with carbon and water solubility, the alkenyl group preferably has 4 or more carbon atoms, more preferably 6 to 100, and even more preferably 8 to 30. Examples of such alkenyl groups include an oleyl group and a linoleyl group.

[0047] The alkenyl group may or may not have a substituent. Examples of such a substituent include an alkyl group, a cycloalkyl group, an aryl group, and an aralkyl group. Examples of the aralkyl group include those described above, and examples of the cycloalkyl group and the aryl group include those described below.

[0048] The alkyl group as a substituent of the alkenyl group is preferably an alkyl group having 1 to 6 carbon atoms, specifically, 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, etc. are preferred.

[0049] The substituent is not limited to the above, and may have a group derived from a fluorene structure (such as a fluorenyl group). In particular, when importance is placed on water solubility, a phenyl group or the like is preferred as the substituent, and when importance is placed on compatibility with the flaky carbon, a naphthyl group, a fluorenyl group or the like is preferred as the substituent.

[0050] The cycloalkyl group is preferably a cycloalkyl group having 5 to 10 carbon atoms (preferably 5 to 8, particularly 5 to 6), and specifically, a cyclopentyl group, a cyclohexyl group, etc. are preferred.

[0051] The cycloalkyl group may or may not have a substituent, and examples of such a substituent include an alkyl group, an aryl group, and an aralkyl group.

[0052] The alkyl group as a substituent of the cycloalkyl group is preferably an alkyl group having 1 to 6 carbon atoms, specifically, 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, etc.

[0053] Examples of the aryl group and aralkyl group as the substituent of the cycloalkyl group include those exemplified above.

[0054] The substituent is not limited to the above, and may have a group derived from a fluorene structure (such as a fluorenyl group). In particular, when importance is placed on water solubility, a phenyl group or the like is preferred as the substituent, and when importance is placed on compatibility with the flaky carbon, a naphthyl group, a fluorenyl group or the like is preferred as the substituent.

[0055] The aryl group is preferably an aryl group having 6 to 22 carbon atoms (particularly 6 to 18), and any of a monocyclic aryl group, a fused ring aryl group, and a polycyclic aryl group can be used, such as a phenyl group, a naphthyl group, an anthracenyl group, a tetracenyl group, a phenanthrenyl group, a biphenyl group, a terphenyl group, a fluorenyl group, an acenaphthenyl group, an acenaphthylenyl group, a pyrenyl group, a chrysenyl group, a triphenylenyl group, etc. From the viewpoint of affinity with carbon, an aryl group having two or more aromatic rings (a fused ring aryl group and a polycyclic aryl group) is preferred.

[0056] The aryl group may or may not have a substituent, and examples of such a substituent include an alkyl group, a cycloalkyl group, and an aralkyl group.

[0057] The alkyl group as a substituent of the aryl group is preferably an alkyl group having 1 to 6 carbon atoms, specifically, 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, etc.

[0058] Examples of the cycloalkyl group and aralkyl group as the substituent of the aryl group include those exemplified above.

[0059] The substituent is not limited to the above, and may have a group derived from a fluorene structure (such as a fluorenyl group).

[0060] Polyoxyethylene groups are usually hydrophilic, but polyoxyalkylene groups having 3 or more carbon atoms, such as polyoxypropylene groups and polyoxybutylene groups, become more hydrophobic as the degree of polymerization increases, and function as hydrophobic groups. Polyoxypropylene groups with a degree of polymerization of 4 or more and polyoxybutylene groups with a degree of polymerization of 3 or more are particularly preferred. For example, when polyoxyethylene-polyoxypropylene or polyoxyethylene-polyoxybutylene is used as an organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon, the polyoxypropylene group and polyoxybutylene group can also function as hydrophobic groups.

[0061] This polyoxyalkylene group having 3 or more carbon atoms may or may not have a substituent, such as an alkyl group, a cycloalkyl group, an aralkyl group, or an aryl group.

[0062] The alkyl group as a substituent of the polyoxyalkylene group having 3 or more carbon atoms is preferably an alkyl group having 1 to 6 carbon atoms, and specifically, 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, etc. are preferred.

[0063] Examples of the cycloalkyl group, aralkyl group and aryl group as the substituent of the polyoxyalkylene group having 3 or more carbon atoms include those exemplified above.

[0064] The substituent is not limited to the above, and may have a group derived from a fluorene structure (such as a fluorenyl group). In particular, when importance is placed on water solubility, a phenyl group or the like is preferred as the substituent, and when importance is placed on compatibility with the flaky carbon, a naphthyl group, a fluorenyl group or the like is preferred as the substituent.

[0065] From the viewpoints of affinity with carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, dispersibility in water (resistance to aggregation), light weight, processability, ease of codeposition of flaky carbon into plating, etc., such hydrophobic groups are preferably aryl groups and polyoxyalkylene groups having 3 or more carbon atoms, more preferably aryl groups, and even more preferably aryl groups having two or more aromatic rings (fused aryl groups and polycyclic aryl groups). Specific examples of preferred hydrophobic groups include naphthyl groups, anthracenyl groups, tetracenyl groups, phenanthrenyl groups, biphenyl groups, terphenyl groups, fluorenyl groups, acenaphthenyl groups, acenaphthylenyl groups, pyrenyl groups, chrysenyl groups, triphenylenyl groups, polyoxypropylene groups with a degree of polymerization of 4 or more, and polyoxybutylene groups with a degree of polymerization of 3 or more.

[0066] The hydrophilic group possessed by the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon is not particularly limited as long as it can increase the solubility in water of the organic compound having the hydrophilic group and the hydrophobic group having a high affinity for carbon. However, from the viewpoints of the water solubility of the organic compound having the hydrophilic group and the hydrophobic group having a high affinity for carbon, the dispersibility of the flaky carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of the flaky carbon into the plating, etc., it is preferable to use a hydrophilic group represented by any one of the general formulas (1) to (4):

[0067] [ka]

[0068] [In the formula, -OH represents an alcoholic hydroxyl group or a phenolic hydroxyl group. R represents a divalent organic group. X1 represents a hydrogen atom, an alkali metal, NH4, or an organic ammonium. X2 represents a hydrogen atom, an alkali metal, NH4, an organic ammonium, or an alkyl group. The oxygen atom in general formula (2) is an ether bond.] A hydrophilic group represented by the following formula is preferred.

[0069] An organic compound having a hydrophilic group and a hydrophobic group having high affinity for carbon can contain one or more types of such hydrophilic groups. When using multiple hydrophilic groups, multiple types of the same hydrophilic groups may be used, or multiple types of hydrophilic groups represented by the same general formula may be used, or multiple types of hydrophilic groups represented by different general formulas may be used.

[0070] In general formula (1), -OH may be either an alcoholic hydroxyl group or a phenolic hydroxyl group. From the viewpoints of water solubility of organic compounds having a hydrophilic group and a hydrophobic group with high affinity for carbon, dispersibility of flaky carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, and ease of codeposition of flaky carbon into plating, an alcoholic hydroxyl group is preferred. However, when a phenolic hydroxyl group is included (especially when multiple phenolic hydroxyl groups are included), a benzene ring with excellent hydrophobicity is inevitably included, and as a whole, excellent thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, dispersibility in water (resistance to aggregation), light weight, processability, and ease of codeposition of flaky carbon into plating are preferred.

[0071] In particular, when the organic compound has a benzenetriol structure (such as a pyrogallol structure, a hydroxyquinol structure, or a phloroglucinol structure) or a benzenediol structure (such as a catechol structure, a resorcinol structure, or a hydroquinone structure) (especially when two or more of these structures are present), it is particularly excellent in thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, dispersibility in water (resistance to aggregation), light weight, processability, ease of codeposition of flaky carbon into plating, etc. As organic compounds having a hydrophilic group with such a structure and a hydrophobic group that has a high affinity for carbon, not only artificially synthesized compounds but also naturally occurring polyphenols can be used.

[0072] Polyphenol is a general term for compounds also called polyhydric phenols, and refers to compounds in which two or more hydrogen atoms of an aromatic hydrocarbon are replaced with hydroxyl groups, or a mixture thereof. Such polyphenols are not particularly limited, and examples thereof include persimmon tannin, tannic acid, catechin (epicatechin, gallocatechin, epigallocatechin, catechin gallate, epicatechin gallate, gallocatechin gallate, epigallocatechin gallate, etc.), anthocyanin, isoflavone, chlorogenic acid, ellagic acid, curcumin, caffeic acid, quercetin, hesperidin, theaflavin, procyanidins, leucoanthocyanidins, rutin, etc. Among these, from the viewpoints of water solubility of organic compounds having a hydrophilic group and a hydrophobic group with high affinity for carbon, dispersibility of flaky carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc., persimmon tannin, tannic acid, catechin (epicatechin, gallocatechin, epigallocatechin, catechin gallate, epicatechin gallate, gallocatechin gallate, epigallocatechin gallate, etc.), anthocyanins, isoflavones, chlorogenic acid, ellagic acid, curcumin, caffeic acid, etc. are preferred, and tannic acid, catechin (green tea polyphenols, etc.), etc. are more preferred.

[0073] These polyphenols are present in many plants, so plants may be used as they are, or plant extracts may be used. Alternatively, polyphenols may be purified by conventional methods and then used. It is particularly preferable to use purified products (such as alcohol-purified products) because they are more likely to provide benefits such as the water solubility of organic compounds having stable hydrophilic groups and hydrophobic groups with high affinity for carbon, the dispersibility of flaky carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, and ease of codeposition of flaky carbon into plating.

[0074] In general formula (2), the divalent organic group represented by R is not particularly limited, and is preferably a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include aliphatic hydrocarbon groups (such as alkylene groups (or alkylidene groups), cycloalkylene groups, alkylene (or alkylidene)-cycloalkylene groups, and bi- or tricycloalkylene groups), and aromatic hydrocarbon groups (such as arylene groups and alkylene (or alkylidene)-arylene groups).

[0075] In the general formula (2), the alkylene group (or alkylidene group) as the divalent organic group represented by the group R is preferably an alkylene group, and C 1-8 An alkylene group is more preferred, and C 1-4 An alkylene group is more preferred, and C 2-4 Alkylene groups are particularly preferred, and C 2-3 Alkylene groups are most preferred, and specific examples include methylene, ethylene, ethylidene, trimethylene, propylene, propylidene, tetramethylene, ethylethylene, butan-2-ylidene, 1,2-dimethylethylene, pentamethylene, and pentane-2,3-diyl groups.

[0076] In the general formula (2), the cycloalkylene group as the divalent organic group represented by the group R is C 5-10 A cycloalkylene group is preferred, and C 5-8A cycloalkylene group is more preferred, and specific examples thereof include a cyclopentylene group, a cyclohexylene group, a methylcyclohexylene group, and a cycloheptylene group.

[0077] In the general formula (2), the alkylene (or alkylidene)-cycloalkylene group as the divalent organic group represented by the group R is preferably an alkylene-cycloalkylene group, and C 1-6 Alkylene-C 5-10 A cycloalkylene group is more preferred, and C 1-4 Alkylene-C 5-8 Cycloalkylene groups are more preferred, and specific examples include a methylene-cyclohexylene group, an ethylene-cyclohexylene group, an ethylene-methylcyclohexylene group, and an ethylidene-cyclohexylene group.

[0078] In the general formula (2), specific examples of the bi- or tricycloalkylene group as the divalent organic group represented by the group R include a norbornane-diyl group.

[0079] In the general formula (2), the arylene group as the divalent organic group represented by the group R is C 6-10 An arylene group is preferred, and specific examples thereof include a phenylene group and a naphthalenediyl group.

[0080] In the general formula (2), the alkylene (or alkylidene)-arylene group as the divalent organic group represented by the group R is preferably an alkylene-arylene group, and C 1-6 Alkylene-C 6-20 An arylene group is more preferred, and C 1-4 Alkylene-C 6-10 An arylene group is more preferred, and C 1-2 Alkylene-phenylene groups are particularly preferred, and specific examples include methylene-phenylene groups, ethylene-phenylene groups, ethylene-methylphenylene groups, and ethylidenephenylene groups.

[0081] The divalent organic group represented by the group R is, among these, a divalent aliphatic hydrocarbon group, in particular, an alkylene group (e.g., a methylene group, an ethylene group, a trimethylene group, etc.) 1-4 alkylene groups, etc.) are preferred.

[0082] The alkylene (or alkylidene)-cycloalkylene group and the alkylene (alkylidene)-arylene group refer to a group represented by -Ra-Rb- (wherein Ra represents an alkylene group or alkylidene group bonded to different oxygen atoms in general formula (2), and Rb represents a cycloalkylene group or an arylene group).

[0083] The hydrophilic group represented by general formula (2) is not particularly limited, and examples thereof include -OCH2CHO-, -OCH2CH2CHO-, and -OCH2O-. Those having a plurality of these (preferably 3 to 100) are also preferably used, such as trioxyethylene, tetraoxyethylene, polyoxymethylene, polyoxyethylene, and polyoxytrimethylene groups. In particular, when the hydrophilic group represented by general formula (2) has a structure in which three or more hydrophilic groups are polymerized, the more carbon atoms in R (e.g., 3 or more carbon atoms), the more likely the hydrophilicity decreases and the more likely the hydrophobicity increases. Therefore, -OCH2CHO- and -OCH2O- are preferred, as they tend to maintain hydrophilicity even with an increased degree of polymerization. Among those having a plurality of these (preferably 3 to 100), trioxyethylene, tetraoxyethylene, polyoxymethylene, and polyoxyethylene groups are preferred, with polyoxyethylene groups being particularly preferred.

[0084] When the hydrophilic group represented by such general formula (2), particularly a polyoxyalkylene group, or even a polyoxyethylene group, is present, the hydrophilic group and the organic compound having a hydrophobic group with high affinity for carbon tend to have particularly excellent water solubility, dispersibility of flaky carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, and the like.

[0085] In the general formula (3), the alkali metal represented by X1 is not particularly limited, and examples thereof include sodium, potassium, and lithium.

[0086] In the general formula (3), the organic ammonium represented by X1 is preferably a quaternary ammonium, and tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, etc. can be suitably used.

[0087] The hydrophilic group represented by the general formula (3) is not particularly limited, but for example, -SO3 - H + , -SO3 - Na + , -SO3 - K + , -SO3 - Li + , -SO3 - NH4 + , -SO3 - N(CH3)4 + , -SO3 - N(C2H5)4 + , -SO3 - N(C3H7)4 + , -SO3 - N(C4H9)4 + etc.

[0088] In the general formula (4), examples of the alkali metal and organic ammonium represented by X2 include those exemplified above.

[0089] In general formula (4), the alkyl group represented by X2 may be a linear alkyl group or a branched alkyl group, but a linear alkyl group is preferred from the viewpoints of affinity with carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity with carbon, dispersibility of flaky carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc. Furthermore, the number of carbon atoms in the alkyl group is preferably 1 to 2 from the viewpoints of affinity with carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity with carbon, dispersibility of flaky carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc.

[0090] The hydrophilic group represented by the general formula (4) is not particularly limited, but examples thereof include -COOH, -COONa, -COOK, -COOLi, -COONH4, -COON(CH3)4, -COON(C2H5)4, and -COON(C3H7)4. + , -COON(C4H9)4 + etc.

[0091] Among these hydrophilic groups, hydrophilic groups represented by general formula (1) or (2) are preferred from the viewpoints of water solubility of organic compounds having a hydrophilic group and a hydrophobic group with high affinity for carbon, stability independent of pH, dispersibility of flaky carbon, water solubility of organic compounds having a hydrophilic group and a hydrophobic group with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc.

[0092] However, when a compound has multiple identical hydrophilic groups represented by general formula (2), i.e., when it has a polymerized structure, the hydrophilicity of the water-soluble compound increases as the degree of polymerization increases for compounds with two or fewer carbon atoms, but the hydrophobicity of the compound may increase as the degree of polymerization increases for compounds with three or more carbon atoms.

[0093] Furthermore, in the present invention, when a nonionic material (such as a nonionic surfactant) is used as the organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon, the HLB value thereof is preferably 12 or more, more preferably 13 to 19, from the viewpoints of the water solubility of the organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon, the dispersibility of flaky carbon, the water solubility of the organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc. Note that, when the hydrophobic group is the same (when the affinity with flaky carbon is about the same), the higher the HLB value, the better.

[0094] The organic compound having a hydrophilic group and a hydrophobic group having high affinity for carbon that satisfy the above conditions is not particularly limited, and may be an aromatic water-soluble compound or a non-aromatic water-soluble compound, although an aromatic water-soluble compound is preferred. Examples of organic compounds having a hydrophilic group and a hydrophobic group with high affinity for carbon include polyoxyethylene naphthyl ether, polyoxypropylene naphthyl ether, polyoxyethylene octylphenyl ether, polyoxypropylene octylphenyl ether, polyoxyethylene undecylphenyl ether, polyoxypropylene undecylphenyl ether, polyoxyethylene tridecylphenyl ether, polyoxypropylene tridecylphenyl ether, polyoxyethylene pentadecylphenyl ether, polyoxypropylene pentadecylphenyl ether, persimmon tannin, tannic acid, catechins (epicatechin, gallocatechin, epigallocatechin, catechin gallate, epicatechin gallate, gallocatechin gallate, epigallocatechin gallate, etc.), anthocyanins, isoflavones, chlorogenic acid, ellagic acid, curcumin, Examples of suitable flaky carbon nanotubes include amine, caffeic acid, quercetin, hesperidin, theaflavin, procyanidins, leucoanthocyanidins, and rutin. Among these, polyoxyethylene naphthyl ether, plant polyphenols such as persimmon tannin, tannic acid, catechin (epicatechin, gallocatechin, epigallocatechin, catechin gallate, epicatechin gallate, gallocatechin gallate, epigallocatechin gallate, etc.), anthocyanins, isoflavones, chlorogenic acid, ellagic acid, curcumin, and caffeic acid are preferred from the standpoints of water solubility of organic compounds having a hydrophilic group and a hydrophobic group with high affinity for carbon, dispersibility of flaky carbon, water solubility of organic compounds having a hydrophilic group and a hydrophobic group with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, and ease of codeposition of flaky carbon into plating.

[0095] The organic compound having such a hydrophilic group and a hydrophobic group having a high affinity for carbon is not particularly limited, but examples thereof include Emulgen 103, Emulgen 104P, Emulgen 105, Emulgen 106, Emulgen 108, Emulgen 109P, Emulgen 120, Emulgen 123P, Emulgen 130K, Emulgen 147, Emulgen 150, Emulgen 210P, and Emulgen 220 (all polyoxyethylene alkyl ethers manufactured by Kao Corporation), Triton X-100, Triton X-114, Triton X-305, and Triton X-405 (all polyoxyethylene octylphenyl ethers manufactured by Dow Chemical Company), and Examples of usable ingredients include polyoxyethylene naphthyl ethers), Noigen EN, Noigen EN-10 (all of which are polyoxyethylene naphthyl ethers manufactured by Daiichi Kogyo Seiyaku Kogyo Co., Ltd.), persimmon tannin, tannic acid, catechins (including polyphenols such as epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate, gallocatechin, catechin gallate, and gallocatechin gallate), anthocyanins, isoflavones, chlorogenic acid, ellagic acid, curcumin, caffeic acid, quercetin, hesperidin, theaflavin, procyanidins, leucoanthocyanidins, rutin, gallic acid, gallic acid esters, and persimmon tannins (including tannins).

[0096] The content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon in the plating solution additive of the present invention is not particularly limited, but from the viewpoints of water solubility of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon, dispersibility of the flaky carbon, water solubility of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of the flaky carbon into the plating, etc., the content is preferably 0.1 to 90 mass%, more preferably 0.5 to 70 mass%, of the total amount of the plating solution additive of the present invention (100 mass%). Furthermore, the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon in the plating solution additive of the present invention is 0.1 to 100 mass parts, preferably 0.5 to 10 mass parts, per 1 mass part of the flaky carbon. If the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon is less than 0.1 parts by mass, the water solubility of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon, the dispersibility of the flaky carbon, the water solubility of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of the flaky carbon into the plating, etc. Also, if the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon exceeds 100 parts by mass, it becomes difficult to powderize and becomes difficult to handle, such as being lightweight.

[0097] When the plating solution additive of the present invention contains water, the water prevents aggregation, so the mass ratio of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon to the flaky carbon can be reduced compared to when the plating solution additive does not contain water. Therefore, the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon in the plating solution additive of the present invention can be 0.5 to 20 parts by mass per part by mass of the flaky carbon. When the plating solution additive of the present invention is in the form of an aqueous dispersion, strong aggregation is less likely to occur, so the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon in the plating solution additive of the present invention can be 0.1 to 10 parts by mass per part by mass of the flaky carbon.

[0098] When the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon is low, the plating solution additive of the present invention has a configuration in which the surface of the flaky carbon is coated with an organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon (Figure 1). On the other hand, when the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon is high, the plating solution additive of the present invention has a configuration in which the flaky carbon is dispersed in the organic compound having a hydrophobic group with a high affinity for carbon (Figure 2). In either case, the presence of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon around the flaky carbon suppresses aggregation of the flaky carbon, resulting in a material that is particularly excellent in terms of the water solubility of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon, the dispersibility of the flaky carbon, the water solubility of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, and ease of codeposition of the flaky carbon into the plating.

[0099] (1-3) Other ingredients The plating solution additive of the present invention may contain other components in addition to the flaky carbon and the organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon. Examples of such other components include carbon microcoils, carbon fibers (particularly carbon nanofibers with a fiber diameter of 500 nm or less), activated carbon, carbon black (acetylene black, oil furnace black, etc.; particularly, ketjen black, which has high conductivity and a large specific surface area), glassy carbon, carbon microcoils, fullerenes, and biomass-based carbon materials (such as bagasse, sorghum, wood chips, sawdust, bamboo, bark, rice straw, rice husks, coffee grounds, used tea leaves, soybean pulp, rice bran, and other raw materials). Other examples of usable materials include carbon fibers produced from lignin, cellulose nanofibers, boron nitride, molybdenum compounds (molybdenum disulfide, organic molybdenum, etc.), tungsten disulfide, fluororesins (polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), etc.), melamine cyanurate, phthalocyanine, lead oxide, calcium fluoride, and layered minerals (mica, talc, etc.), as long as the effects of the present invention are not impaired.

[0100] However, from the viewpoints of dispersibility of flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc., it is preferable that the content of other components is small, and is preferably 0.01 to 10 mass%, more preferably 0.02 to 5 mass%, assuming the total amount of the plating solution additive of the present invention as 100 mass%.

[0101] (1-4) Plating solution additives The form of the plating solution additive of the present invention is not particularly limited, and examples thereof include a fluid liquid such as a dispersion or slurry, and a solid such as a powder or a lump.

[0102] The plating solution additive of the present invention may also be in a semi-solid form containing water.

[0103] When the plating solution additive of the present invention is prepared as a dispersion in a solvent containing water, the content of flaky carbon in the plating solution additive of the present invention is not particularly limited. However, from the viewpoints of dispersibility of the flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of the flaky carbon into the plating, etc., the content is preferably 0.1 to 15 mass%, and more preferably 0.5 to 10 mass%, of the total amount of the plating solution additive of the present invention taken as 100 mass%.

[0104] When the plating solution additive of the present invention is prepared as a dispersion in a solvent containing water, the content of the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon in the plating solution additive of the present invention is not particularly limited. However, from the viewpoints of dispersibility of flaky carbon, water solubility of the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc., the content is preferably 0.01 to 30 mass%, more preferably 0.1 to 15 mass%, based on 100 mass% of the total amount of the plating solution additive of the present invention.

[0105] When the plating solution additive of the present invention is prepared as a dispersion in a solvent containing water, it is preferable to use water as the main solvent from the viewpoints of environmental friendliness and ease of removal.

[0106] The water content in the solvent used is not particularly limited, but from the viewpoints of dispersibility of flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity to carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc., the water content is preferably 70 mass% or more (70 to 100 mass%), and more preferably 80 mass% or more (80 to 100 mass%), assuming the total amount of solvent to be 100 mass%.

[0107] When the plating solution additive of the present invention is prepared as a dispersion in a solvent containing water, the content of water in the plating solution additive of the present invention is not particularly limited. However, from the viewpoints of dispersibility of flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc., the content of water is preferably 25% by mass or more (25 to 100% by mass), and more preferably 50 to 99% by mass, based on 100% by mass of the total amount of the plating solution additive of the present invention.

[0108] In the present invention, only water may be used as the solvent, and an organic solvent does not necessarily have to be used. However, in order to further improve the dispersibility of the flaky carbon and the water solubility of organic compounds having hydrophilic groups and hydrophobic groups that have high affinity with carbon, organic solvents such as alcohols such as methanol, ethanol, 2-propanol, and tert-butyl alcohol; glycols such as ethylene glycol; glycerin; and 2-methoxyethanol may be used.

[0109] The content of the organic solvent in the solvent used is not particularly limited, but from the viewpoints of dispersibility of the flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity to carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of the flaky carbon into the plating, etc., the content is preferably 30% by mass or less (0 to 30% by mass), and more preferably 20% by mass or less (0 to 20% by mass), assuming the total amount of solvent to be 100% by mass.

[0110] When the plating solution additive of the present invention is prepared as a dispersion in a solvent containing water, the content of the organic solvent in the plating solution additive of the present invention is not particularly limited. However, from the viewpoints of dispersibility of flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc., the content is preferably 0 to 20 mass%, more preferably 0 to 10 mass%, based on the total amount of the plating solution additive of the present invention being 100 mass%.

[0111] As described above, the plating solution additive of the present invention has excellent dispersibility of flaky carbon and excellent water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, and can suppress the aggregation of foil-modified carbon.Furthermore, it can easily codeposit flaky carbon during plating without pretreatment or reaction, and as a result, it is possible to impart properties to the plating such as thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, and processability.

[0112] The plating solution additive of the present invention can be used for plating electronic parts, automobile parts, and the like.

[0113] 2. Manufacturing method of plating solution additives The plating solution additive of the present invention may be, for example, (1) A step of removing the solvent from a flaky carbon dispersion containing the flaky carbon, an organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon, and a solvent, the flaky carbon dispersion containing 0.1 to 100 parts by mass of the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon per 1 part by mass of the flaky carbon. It can be produced by

[0114] In addition, when the plating solution additive of the present invention is a dispersion in a solvent containing water, a flaky carbon dispersion containing the flaky carbon, an organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon, and a solvent, and containing 0.1 to 100 parts by mass of the organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon per 1 part by mass of the flaky carbon, can be used as is as the plating solution additive of the present invention.

[0115] (2-1) Dispersion (flaky carbon dispersion) In a dispersion (flaky carbon dispersion) containing flaky carbon, an organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon, and a solvent, the above-mentioned explanations can be applied to the flaky carbon and the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon. In addition, the flaky carbon dispersion can contain other components as needed.

[0116] This flaky carbon dispersion may be formed as a dispersion or as a coating on a substrate. When the plating solution additive of the present invention is a dispersion in a solvent containing water, it is preferably formed as a dispersion. Furthermore, as the solvent used to prepare the flaky carbon dispersion (flaky carbon dispersion or flaky carbon coating), water is preferably used as the primary solvent from the viewpoints of the dispersibility of flaky carbon, the water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, the thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, and ease of codeposition of flaky carbon into plating. In other words, the details of the flaky carbon dispersion can be the same as those of the plating solution additive as a dispersion described above.

[0117] (2-2) Method for producing flaky carbon dispersion In the present invention, the method for producing the flaky carbon dispersion is not particularly limited, and it is also possible to add flaky carbon and an organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon to a solvent. Specifically, flaky carbon can be added to a dispersion of an organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon, or an organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon can be added to a dispersion of flaky carbon. Furthermore, flaky carbon and an organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon can be simultaneously added to a solvent.

[0118] However, from the viewpoint of further improving the dispersibility of the flaky carbon to make it less likely to aggregate and further enhancing the thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, lightness, processability, ease of codeposition of the flaky carbon into plating, etc. of the resulting plating solution additive of the present invention, it is preferable to place a composition containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon between a rotating turntable and a turntable placed approximately parallel to the turntable, and to apply shear to the carbonaceous material in the composition while adjusting the shortest distance between the turntable and the turntable to be 200 μm or less (grinding method).

[0119] Alternatively, the flaky carbon dispersion can be preferably produced by subjecting a composition containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon to a pressure treatment of 30 MPa or more (high-pressure dispersion method).

[0120] From the viewpoints of dispersibility of the flaky carbon, the thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of the flaky carbon into the plating, and the like, the grinding method is most preferred.

[0121] Conventionally, when producing flaky carbon by a wet method, a water dispersion containing flaky carbon oxide and an aqueous solvent was subjected to a reduction treatment. However, this method made it difficult to maintain the graphene structure and the resulting flaky carbon severely aggregated, making it difficult to obtain a flaky carbon aqueous dispersion. There were also safety issues. In contrast, the present invention uses an organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon, allowing the flaky carbon to be obtained in a uniformly dispersed state (flaky carbon dispersion) without aggregating while maintaining the graphene structure. The resulting flaky carbon is also less likely to be broken, can be obtained in a short time, and is less likely to leave any clumps that failed to peel. In this case, the organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon can also function as a dispersant for uniformly dispersing the flaky carbon.

[0122] Furthermore, with the shearing method, the direction of force application is parallel to the surface direction of the carbonaceous material having a layered structure, and processing is performed in a narrow space. Therefore, compared with conventional manufacturing methods using high-speed stirring, ultrasonic processing, etc., there is less destruction and larger-sized flaky carbon (for example, flaky carbon with a size of 1 μm or more) can be obtained. The peeling efficiency is high, processing can be performed in a short time (few passes), and thick lumps that fail to peel are less likely to remain.

[0123] Carbonaceous material with layered structure The carbonaceous material having a layered structure is not particularly limited, and examples thereof include natural graphite, artificial graphite, expanded graphite, amorphous graphite, and graphite oxide. Graphite oxide can be graphite oxidized with one or more oxidizing agents, such as sulfuric acid, nitric acid, potassium permanganate, and hydrogen peroxide. For example, when graphite oxide is obtained by the Hummers process, graphite is immersed in concentrated sulfuric acid, potassium permanganate is added to oxidize the graphite, and the reaction product is quenched with dilute sulfuric acid and / or hydrogen peroxide, and then washed with distilled water, whereby oxygen atoms are bonded to the carbon atoms, introducing oxygen atoms between the layers, and graphite oxide can be obtained.

[0124] Among these, when attempting to obtain high-purity flaky carbon that does not contain heteroatoms such as oxygen, it is preferable to use graphite as the raw material, and natural graphite and expanded graphite are more preferable. When using expanded graphite, it is preferable to adopt expanded graphite that has less oxidation of the graphene structure. When using expanded graphite, it may be used after being subjected to a heat treatment at about 300 to 1000°C for about 10 seconds to 5 hours. This makes it possible to obtain expanded graphite that has been suitably expanded.

[0125] Furthermore, when ease of production is important, graphite oxide may be used. By using graphite oxide, solvent molecules are easily inserted between the layers, making it easy to exfoliate only in the layer direction, and the exfoliation efficiency and dispersibility are improved, making it possible to further shorten the processing time. However, when graphite oxide is used, a subsequent reduction treatment is required, and from the viewpoint of better maintaining the graphene structure, conductivity, and strength, other materials (natural graphite, artificial graphite, expanded graphite, amorphous graphite) are preferred.

[0126] On the other hand, amorphous graphite can be used to further improve dispersibility, but from the viewpoints of crystallinity, purity, and structural maintenance, other materials (natural graphite, artificial graphite, expanded graphite, and graphite oxide) are preferred.

[0127] Furthermore, when emphasis is placed on the crystallinity, strength, structural integrity, etc. of the resulting flaky carbon, artificial graphite can also be used.

[0128] In the present invention, the content of the carbonaceous material having a layered structure in a composition containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon is not particularly limited. However, it is preferably 20% by mass or less, more preferably 0.0001 to 15% by mass, and even more preferably 0.001 to 10% by mass, based on 100% by mass of the total amount of the composition used to produce the flaky carbon dispersion. A lower content of the carbonaceous material having a layered structure is more likely to cause exfoliation (delamination), which tends to result in more efficient production of flaky carbon, fewer treatment cycles, and tends to facilitate maintaining an appropriate viscosity and performing shearing treatments, etc. On the other hand, a higher content of the carbonaceous material having a layered structure results in better productivity. Therefore, it is preferable to appropriately set the content of the carbonaceous material having a layered structure from the viewpoint of balancing exfoliation efficiency, viscosity, productivity, and the like. When a carbonaceous material dispersion is used, it is preferable to set the content of the carbonaceous material having a layered structure in the flaky carbon dispersion within the above-mentioned range.

[0129] Organic compounds with hydrophilic groups and hydrophobic groups that have a high affinity for carbon As the organic compound having a hydrophilic group and a hydrophobic group having high affinity for carbon, those mentioned above can be used.

[0130] In the present invention, the content of the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon in the composition used to produce the flaky carbon dispersion is not particularly limited, but is preferably 0.00001 to 40 mass%, more preferably 0.0001 to 15 mass%, and even more preferably 0.001 to 10 mass%, based on 100 mass% of the total amount of the composition used to produce the flaky carbon dispersion. Meanwhile, in the present invention, the content of the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon in the composition used to produce the flaky carbon dispersion is preferably 0.01 to 1.0 part by mass, more preferably 0.02 to 0.8 part by mass, based on 1 part by mass of the carbonaceous material having a layered structure. The lower the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon, the higher the content of the carbonaceous material having a layered structure. This tends to improve the thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, and ease of codeposition of flaky carbon into plating, and also facilitates inexpensive processing. On the other hand, the higher the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon, the more likely exfoliation (delamination) occurs, and therefore flaky carbon tends to be obtained more efficiently. However, considering the exfoliation efficiency, it is preferable that the content be not too high. When a carbonaceous material dispersion is used in this production method, the content of the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon in the carbonaceous material dispersion is preferably within the above-mentioned range.

[0131] solvent In the above-mentioned method for producing a flaky carbon dispersion, as described above, it is preferable to perform a specific treatment using a composition containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon. However, from the viewpoints of the efficiency of flaking the carbonaceous material having a layered structure, the thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc., it is preferable to perform a specific treatment on a carbonaceous material dispersion containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon.

[0132] The carbonaceous material dispersion may be formed as a dispersion liquid or may be formed as a coating film on a substrate.

[0133] In this case, the solvent used to prepare the carbonaceous material dispersion (carbonaceous material dispersion or carbonaceous material coating) can be any of the solvents described above.

[0134] In the present invention, when a specific treatment is carried out using a carbonaceous material dispersion using a solvent, the total amount of solvent in the carbonaceous material dispersion is not particularly limited, but from the viewpoints of the exfoliation efficiency of the carbonaceous material having a layered structure, the solubility of an organic compound having a hydrophilic group and a hydrophobic group that has high affinity for carbon, and the like, the total amount of solvent is preferably 40 to 99.9998 mass%, more preferably 63 to 99.998 mass%, and even more preferably 85 to 99.98 mass%, where the total amount of the carbonaceous material dispersion is taken as 100 mass%.

[0135] In the present invention, when a specific treatment is performed using a carbonaceous material dispersion using a solvent, the carbonaceous material dispersion may be prepared by adding a carbonaceous material having a layered structure to an organic compound dispersion having a hydrophilic group and a hydrophobic group that has a high affinity for carbon, or by adding an organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon to a carbonaceous material dispersion having a layered structure. Alternatively, the carbonaceous material having a layered structure and the organic compound having a hydrophilic group and a hydrophobic group that has a high affinity for carbon may be simultaneously added to a solvent.

[0136] Other ingredients In the present invention, other components may be included in a composition (e.g., a carbonaceous material dispersion) containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon. This allows these other components to be included in the final flaky carbon dispersion or electromagnetic wave absorbing material. The above-mentioned other components can be used as such other components, provided that the effects of the present invention are not impaired. However, from the viewpoint of easily obtaining a plating solution additive that is particularly excellent in thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, and ease of codeposition of flaky carbon into plating, the content of the other components is preferably low, preferably 0.00001 to 5 mass %, and more preferably 0.0001 to 2 mass %, of the total amount of the carbonaceous material dispersion taken as 100 mass %.

[0137] Shearing treatment (grinding method) In the present invention, when the attrition method is adopted, as described above, it is preferable to place a composition containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon between a rotating turntable and a turntable placed approximately parallel to the turntable, and to perform a treatment to apply shear to the carbonaceous material in the composition while adjusting the shortest distance between the turntable and the turntable to 200 μm or less. Note that, when a carbonaceous material dispersion is used, it is preferable to place the carbonaceous material dispersion between a rotating turntable and a turntable placed approximately parallel to the turntable, and to perform a treatment to apply shear to the carbonaceous material in the carbonaceous material dispersion while adjusting the shortest distance between the turntable and the turntable to 200 μm or less.

[0138] Shearing treatment causes atomization of the carbonaceous material having a layered structure, and although it may not be possible to maintain the graphene structure depending on the conditions, it can efficiently exfoliate the carbonaceous material having a layered structure and reduce the processing time. When performing such shearing treatment, the rotating disk and the disk are placed approximately parallel, but they do not have to be strictly parallel. Specifically, the angle between the axis perpendicular to the rotating disk and the axis perpendicular to the disk is preferably 10° or less, more preferably 5° or less. It is most preferable that the axis perpendicular to the rotating disk and the axis perpendicular to the disk are strictly parallel. The shortest distance between the two surfaces when performing such shearing treatment is not particularly limited as long as it can sufficiently exfoliate the carbonaceous material having a layered structure, but is preferably 200 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less. The shorter the shortest distance between the two surfaces when performing shearing treatment, the higher the exfoliation efficiency, and it is usually 0 μm. In the present invention, the shortest distance between the two surfaces during shearing refers to the measured shortest distance between the turntables, excluding the thickness of the composition containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon. In other words, a measured shortest distance of 0 μm between the turntables means that the composition containing the carbonaceous material having a layered structure and the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon is placed in close contact between the turntables and the disks. In other words, no space exists between the turntables and the disks other than the carbonaceous material having a layered structure and the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon. Although the turntables and the disks are arranged approximately parallel, the distance between the turntables and the disks may vary depending on the location. In this case, the shortest distance between the turntables and the disks refers to the shortest distance between the turntables and the disks. Furthermore, it is not necessary to space the turntables apart in advance, and the material to be processed may be sandwiched between the turntables and the disks. Alternatively, the turntables and the disks may be brought into contact with each other, and the space between the turntables and the disks may be widened by sandwiching a carbonaceous material having a layered structure therebetween.Such shearing treatment can be carried out using any device that can rotate a disk-like object, such as a millstone, a vibration mixer, a spin coater, or a grinder.

[0139] The size of the turntable that can be used in this case is not particularly limited, and is preferably 5 to 500 mm, more preferably 10 to 200 mm. The rotation speed of the turntable when performing the shearing treatment is not particularly limited, and is preferably within a range that allows the carbonaceous material having a layered structure to be sufficiently exfoliated, for example, preferably 1000 to 10000 ppm, more preferably 2000 to 5000 ppm.

[0140] By carrying out such a shearing treatment, the disk and the carbonaceous material having a layered structure, and the carbonaceous material having a layered structure and the carbonaceous material having a layered structure can be brought into contact with each other, and shear can be applied to the carbonaceous material having a layered structure in a direction parallel to the graphene layers of the carbonaceous material having a layered structure.

[0141] By reducing the minimum distance between the rotating disks and increasing the rotation speed of the rotating disks during the shearing treatment, it is possible to make the conditions stronger, thereby more efficiently flaking the carbonaceous material having a layered structure and further reducing the treatment time. This shearing operation can be performed one or more times, preferably three or more times.

[0142] The temperature at which the shearing treatment is carried out is not particularly limited, and may be any temperature that can sufficiently exfoliate the carbonaceous material having a layered structure, and may be 0° C. or higher, preferably 0 to 100° C., and particularly 20 to 95° C. The temperature at which the shearing treatment is carried out is preferably under conditions that result in high solubility of an organic compound having a hydrophilic group and a hydrophobic group that has high affinity for carbon, and if the higher the temperature, the higher the temperature, the greater the solubility.If a water-soluble compound having a cloud point is used, the temperature is preferably maintained at or below the cloud point.

[0143] Before carrying out the shearing treatment, in order to bring the carbonaceous material having a layered structure and the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon into intimate contact with each other, the materials may be stirred in advance using a stirring device, ultrasonic dispersing device, or the like before preparing the composition, thereby allowing the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon to blend with the surface of the carbonaceous material having a layered structure.

[0144] In the present invention, when graphite oxide is used as the carbonaceous material having a layered structure, it exists as a flaky carbon oxide in the dispersion after the shearing treatment. Therefore, when graphite oxide is used as the carbonaceous material having a layered structure, it is preferable to perform a reduction treatment as a post-treatment. Various methods, such as chemical reduction and electrochemical reduction, can be used for the reduction treatment, but chemical reduction is preferred. Among these, chemical reduction using a reducing agent such as hydrazine or sodium borohydride is preferred. The amount of the reducing agent is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.5 to 3 parts by mass, per part by mass of the flaky carbon oxide. Furthermore, heating during reduction facilitates the reduction. The heating temperature is preferably 40 to 200°C, more preferably 50 to 150°C, and even more preferably 60 to 120°C. The reduction time is preferably 10 minutes to 64 hours, more preferably 30 minutes to 48 hours, and even more preferably 1 to 24 hours. However, it is preferable that the amount be such that the graphene structure is not excessively destroyed.

[0145] The shearing treatment described above can produce flaky carbon as the flaky carbon dispersion described above. Because this shearing treatment contains an organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon, the flaky carbon dispersion also contains an organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon. This organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon can adsorb onto the flaky carbon surface and disperse the flaky carbon in a solvent at a high concentration, thus functioning as a dispersant in the flaky carbon dispersion. Furthermore, the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon can be commercially available, offering advantages over conventional products in both cost and dispersibility. Furthermore, because the organic compound having a hydrophilic group and a hydrophobic group with a high affinity for carbon remains on the flaky carbon surface, the resulting plating solution additive of the present invention exhibits excellent thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, and ease of codeposition of flaky carbon into plating.

[0146] However, the material immediately after this shearing treatment tends to have a high content of organic compounds having hydrophilic groups and hydrophobic groups that have a high affinity for carbon, which may lead to plasticization of the plating solution additives and problems with processability. Therefore, by washing the obtained flaky carbon dispersion, the content of organic compounds having hydrophilic groups and hydrophobic groups that have a high affinity for carbon can be reduced, thereby increasing the freedom in the formulation of plating solution additives and improving processability.

[0147] Specifically, it is preferable to add an alcohol such as ethanol or 2-propanol to the obtained flaky carbon dispersion and filter it, and then add a ketone such as acetone or 2-butanone to the obtained cake and filter it.

[0148] The content of the solvent that can be used in this case is not particularly limited, but the alcohol is preferably 1 to 20 parts by mass (particularly 1.5 to 10 parts by mass) per part by mass of the flaky carbon dispersion, and the ketone is preferably 1 to 50 parts by mass (particularly 1.5 to 30 parts by mass) per part by mass of the cake.

[0149] Furthermore, in conventional methods involving oxidation and reduction treatments, it was impossible to form a flaky carbon dispersion on a plastic substrate because the plastic substrate was hydrolyzed during the reduction treatment, and the reduction treatment caused the flaky carbon to aggregate and no longer exist as a dispersion. However, in the present invention, by incorporating an organic compound having the above-mentioned hydrophilic group and a hydrophobic group that has a high affinity for carbon and performing a specific treatment, it is also possible to form a flaky carbon dispersion or an electromagnetic wave absorbing material on a plastic substrate such as polyethylene terephthalate (PET) without the substrate being hydrolyzed.

[0150] Pressure treatment (high pressure dispersion method) In the present invention, when a high-pressure dispersion method is adopted, as described above, it is preferable to subject a composition containing a carbonaceous material having a layered structure and an organic compound having a hydrophilic group and a hydrophobic group having high affinity for carbon to a pressure treatment of 30 MPa or more.

[0151] Pressure treatment causes atomization of the carbonaceous material having a layered structure, and although it may not be possible to maintain the graphene structure depending on the conditions, it can efficiently exfoliate the carbonaceous material having a layered structure and reduce the treatment time. The pressure level when performing such pressure treatment is not particularly limited as long as it can sufficiently exfoliate the carbonaceous material having a layered structure, but is preferably 30 MPa or higher, more preferably 50 to 400 MPa, and even more preferably 100 to 300 MPa. Such pressure treatment can be performed using a high-pressure dispersion device, a supercritical water production device, or the like. A high-pressure dispersion device can disperse by applying mechanical pressure, and a supercritical water production device can increase the pressure of the system by heating the water.

[0152] Such pressure can, for example, (i) causing two or more of the carbonaceous material dispersions to collide with each other; (ii) colliding the carbonaceous material dispersion with a metal or ceramic material (a high-hardness material such as silicon carbide or alumina); (iii) The carbonaceous material dispersion is formed into a film having a cross-sectional area of 1 cm 2 Passing through the following spaces Processing such as the above can be performed.

[0153] According to the above (i) and (ii), it is possible to apply stronger pressure conditions, which allows the carbonaceous material having a layered structure to be exfoliated more efficiently and the processing time to be further reduced. Furthermore, according to the above (iii), the carbonaceous material having a layered structure can be more appropriately exfoliated while maintaining the graphene structure. This pressure operation can be performed one or more times, preferably ten or more times.

[0154] The pressurizing temperature is not particularly limited as long as it is a temperature at which the carbonaceous material having a layered structure can be sufficiently exfoliated, and in the cases of (i) and (ii) above, it can be 0 to 100°C, particularly 20 to 95°C. In the case of (iii) above, when pressure is applied mechanically, the temperature is preferably 0 to 100°C, and when pressure is generated by the supercritical state of water, the temperature is preferably 373 to 700°C, more preferably 380 to 450°C.

[0155] When the pressure treatment is carried out, it is preferable to carry out an ultrasonic dispersion treatment as a preliminary treatment (pretreatment) to atomize the carbonaceous material having a layered structure, which can have the effect of preventing clogging, etc.

[0156] Although there are no particular limitations on the output power when carrying out ultrasonic dispersion treatment, from the viewpoint of flaking the carbonaceous material having a layered structure, it is preferable to use an output power that is stronger than that of a commonly performed ultrasonic dispersion treatment (about 40 to 50 W). Specifically, the output power of the ultrasonic dispersion treatment is preferably 100 W or more, more preferably 300 to 20,000 W, and even more preferably 400 to 18,000 W.

[0157] The ultrasonic dispersion temperature is not particularly limited as long as it is a temperature at which the carbonaceous material having a layered structure can be sufficiently exfoliated, and may be 0 to 80° C., particularly 10 to 70° C. The ultrasonic dispersion time is not particularly limited as long as it is a time at which the carbonaceous material having a layered structure can be sufficiently exfoliated, and may be 1 to 600 minutes, particularly 3 to 120 minutes.

[0158] Furthermore, as a pre-treatment or post-treatment of these treatments, dispersion treatment using other dispersion devices such as ordinary mechanical stirring, dispersion treatment using an emulsifying device, dispersion treatment using a bead mill, etc. may be used in combination.

[0159] In the present invention, when graphite oxide is used as the carbonaceous material having a layered structure, it exists as a flaky carbon oxide in the dispersion subjected to the pressure treatment. Therefore, when graphite oxide is used as the carbonaceous material having a layered structure, it is preferable to perform a reduction treatment as a post-treatment. Various methods, such as chemical reduction and electrochemical reduction, can be used for the reduction treatment, but chemical reduction is preferred. Among these, chemical reduction using a reducing agent such as hydrazine or sodium borohydride is preferred. The amount of the reducing agent is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.5 to 3 parts by mass, per part by mass of the flaky carbon oxide. Furthermore, heating during reduction facilitates the reduction. The heating temperature is preferably 40 to 200°C, more preferably 50 to 150°C, and even more preferably 60 to 120°C. The reduction time is preferably 10 minutes to 64 hours, more preferably 30 minutes to 48 hours, and even more preferably 1 to 24 hours. However, it is preferable that the amount be such that the graphene structure is not excessively destroyed.

[0160] (2-3) Method for producing the plating solution additive of the present invention When the plating solution additive of the present invention does not contain a solvent, the plating solution additive of the present invention can be obtained by removing the solvent from the above-mentioned flaky carbon dispersion. When the plating solution additive of the present invention contains a solvent, the above-mentioned flaky carbon dispersion can be used as is as the plating solution additive of the present invention.

[0161] When removing the solvent, methods for concentrating the flaky carbon dispersion include drying the flaky carbon dispersion, spin-coating the flaky carbon dispersion onto a substrate, drying the flaky carbon dispersion after application, and recovering the thermal conductive material of the present invention by conventional solid-liquid separation. Examples of methods for performing solid-liquid separation include methods commonly used for solid-liquid separation, such as filtration using filter paper or a glass filter; filtration after centrifugation; and methods using a vacuum filter. Next, the drying method is not particularly limited, and examples include drying using a hot air dryer or the like at about 50 to 200°C for about 1 to 24 hours.

[0162] 3. Plating solution and its manufacturing method The plating solution of the present invention contains the plating solution of the present invention and at least one metal compound selected from the group consisting of nickel compounds, copper compounds, zinc compounds, chromium compounds, tin compounds, silver compounds, and gold compounds.

[0163] In the plating solution of the present invention, the content of flaky carbon is not particularly limited, but from the viewpoints of dispersibility of the flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc., the content is preferably 0.001 to 5 mass%, and more preferably 0.01 to 3 mass%, based on 100 mass% of the total amount of the plating solution of the present invention.

[0164] In the plating solution of the present invention, the content of the organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon is not particularly limited, but from the viewpoints of dispersibility of the flaky carbon, water solubility of the organic compound having a hydrophilic group and a hydrophobic group with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of the flaky carbon into the plating, etc., the content is preferably 0.001 to 10 mass%, and more preferably 0.001 to 5 mass%, of the total amount of the plating solution of the present invention taken as 100 mass%.

[0165] In the plating solution of the present invention, the nickel compound, copper compound, zinc compound, chromium compound, tin compound, silver compound, and gold compound contained therein can be appropriately selected depending on the type of metal to be plated, and are not particularly limited. However, since the plating solution of the present invention preferably uses a solvent containing water as the main solvent, it is preferable to use a water-soluble compound.

[0166] Specific examples of such metal compounds include nickel compounds such as nickel sulfate, nickel chloride, nickel sulfamate, nickel acetate, nickel nitrate, and nickel bicarbonate; copper compounds such as copper sulfate, copper cyanide, and copper pyrophosphate; zinc compounds such as zinc sulfate, zinc chloride, zinc fluoroborate, and zinc acetate; chromium compounds such as chromium chloride, chromium nitrate, chromic acid, and chromium acetate; tin compounds such as tin sulfate, tin fluoroborate, tin pyrophosphate, organic tin sulfonates, tin chloride, sodium stannate, and potassium stannate; silver compounds such as silver cyanide, potassium silver cyanide, sodium silver cyanide, silver nitrate, silver iodide, silver sulfamate, silver thiosulfate, silver thiourea, and silver methanesulfonate; and gold compounds such as potassium silver cyanate, sodium gold cyanate, and sodium gold sulfate. These metal compounds can be used alone or in combination of two or more.

[0167] In the plating solution of the present invention, the content of the above-mentioned metal compound is not particularly limited and varies depending on the application, metal type, plating conditions, etc., but from the viewpoints of dispersibility of flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc., the content is preferably 5 to 40 mass%, more preferably 10 to 35 mass%, of the total amount of the plating solution of the present invention as 100 mass%. Note that when multiple metal compounds are contained in the plating solution of the present invention, it is preferable to adjust the total content thereof to be within the above range.

[0168] The plating solution of the present invention may also be a dispersion in a solvent containing water.

[0169] When the plating solution of the present invention is a dispersion in a solvent containing water, it is preferable to use water as the main solvent from the standpoint of environmental considerations and ease of removal.

[0170] The water content in the solvent used is not particularly limited, but from the viewpoints of dispersibility of flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity to carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc., the water content is preferably 70 mass% or more (70 to 100 mass%), and more preferably 80 mass% or more (80 to 100 mass%), assuming the total amount of solvent to be 100 mass%.

[0171] When the plating solution of the present invention is prepared as a dispersion in a solvent containing water, the content of water in the plating solution of the present invention is not particularly limited. However, from the viewpoints of dispersibility of flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc., the content of water is preferably 50 to 90 mass%, and more preferably 55 to 85 mass%, of the total amount of the plating solution of the present invention taken as 100 mass%.

[0172] In the present invention, only water may be used as the solvent, and an organic solvent does not necessarily have to be used. However, in order to further improve the dispersibility of the flaky carbon and the water solubility of organic compounds having hydrophilic groups and hydrophobic groups that have high affinity with carbon, organic solvents such as alcohols such as methanol, ethanol, 2-propanol, and tert-butyl alcohol; glycols such as ethylene glycol; glycerin; and 2-methoxyethanol may be used.

[0173] The content of the organic solvent in the solvent used is not particularly limited, but from the viewpoints of dispersibility of the flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity to carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of the flaky carbon into the plating, etc., the content is preferably 30% by mass or less (0 to 30% by mass), and more preferably 20% by mass or less (0 to 20% by mass), assuming the total amount of solvent to be 100% by mass.

[0174] When the plating solution of the present invention is a dispersion of a solvent containing water, the content of the organic solvent in the plating solution of the present invention is not particularly limited, but from the viewpoints of dispersibility of flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into the plating, etc., the content is preferably 0 to 10 mass%, more preferably 0 to 5 mass%, of the total amount of the plating solution of the present invention taken as 100 mass%.

[0175] The plating solution of the present invention may contain not only the above-mentioned components but also various additives such as a pH adjuster and a brightener. These various additives may be used alone or in combination of two or more. Furthermore, these various additives may be, for example, additives that are typically contained in plating solutions for nickel, copper, zinc, chromium, tin, silver, gold, etc.

[0176] When an additive is contained in the plating solution of the present invention, the content of the additive in the plating solution of the present invention is not particularly limited and will vary depending on the application and the type of metal to be plated. However, from the viewpoints of dispersibility of flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into the plating, etc., the content of the additive in the plating solution of the present invention is preferably 1 to 30 mass%, more preferably 3 to 25 mass%, based on 100 mass% of the total amount of the plating solution of the present invention.

[0177] The method for producing the plating solution of the present invention described above is not particularly limited, but the plating solution of the present invention can be produced by mixing a solution containing the metal compound with the plating solution additive of the present invention.

[0178] When the plating solution of the present invention contains the additive, it can be added to a solution containing a metal compound. That is, the plating solution of the present invention can be produced by mixing a conventional plating solution with the plating solution additive of the present invention.

[0179] The content of the metal compound in the solution containing the metal compound is not particularly limited and varies depending on the application, metal type, plating conditions, etc., but from the viewpoints of dispersibility of flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc., the content is preferably 10 to 60 mass%, more preferably 15 to 50 mass%, of the total amount of the solution containing the metal compound as 100 mass%. Note that when multiple metal compounds are contained in the solution containing the metal compound, it is preferable to adjust the total content so that it is within the above range.

[0180] When the additives are added to the solution containing the metal compound, the content of the additives is not particularly limited and varies depending on the application, metal type, plating conditions, etc., but from the viewpoints of dispersibility of the flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of the flaky carbon into the plating, etc., the content of the additives is preferably 0.1 to 100 mass%, more preferably 0.5 to 50 mass%, of the total amount of the solution containing the metal compound as 100 mass%. Note that when multiple additives are included in the solution containing the metal compound, it is preferable to adjust the total content of the additives to be within the above range.

[0181] The solution containing the metal compound is not particularly limited as long as it uses a solvent that can dissolve the metal compound. However, as described above, it is preferable to use a solvent containing water as the main solvent for the plating solution of the present invention, and therefore it is also preferable to use a solvent containing water as the main solvent here.

[0182] The water content in the solvent used is not particularly limited, but from the viewpoints of dispersibility of flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity to carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc., the water content is preferably 70 mass% or more (70 to 100 mass%), and more preferably 80 mass% or more (80 to 100 mass%), assuming the total amount of solvent to be 100 mass%.

[0183] When the solution containing the metal compound is a solution in a solvent containing water, the content of water in the solution containing the metal compound is not particularly limited, but from the viewpoints of dispersibility of the flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of the flaky carbon into the plating, etc., the content of water is preferably 40 to 85 mass%, and more preferably 50 to 80 mass%, of the total amount of the solution containing the metal compound being 100 mass%.

[0184] In the present invention, only water may be used as the solvent, and an organic solvent does not necessarily have to be used. However, in order to further improve the dispersibility of the flaky carbon and the water solubility of organic compounds having hydrophilic groups and hydrophobic groups that have high affinity with carbon, organic solvents such as alcohols such as methanol, ethanol, 2-propanol, and tert-butyl alcohol; glycols such as ethylene glycol; glycerin; and 2-methoxyethanol may be used.

[0185] The content of the organic solvent in the solvent used is not particularly limited, but from the viewpoints of dispersibility of the flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity to carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of the flaky carbon into the plating, etc., the content is preferably 30% by mass or less (0 to 30% by mass), and more preferably 20% by mass or less (0 to 20% by mass), assuming the total amount of solvent to be 100% by mass.

[0186] When the solution containing the metal compound is a solution in a solvent containing water, the content of the organic solvent in the solution containing the metal compound is not particularly limited, but from the viewpoints of dispersibility of the flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity to carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of the flaky carbon into the plating, etc., the content of the organic solvent is preferably 0 to 10 mass%, and more preferably 0 to 5 mass%, of the total amount of the solution containing the metal compound being 100 mass%.

[0187] The mixing ratio of the solution containing the metal compound and the plating solution additive of the present invention is not particularly limited, but from the viewpoints of dispersibility of flaky carbon, water solubility of organic compounds having hydrophilic groups and hydrophobic groups with high affinity for carbon, thermal conductivity (heat dissipation), electrical conductivity, lubricity, wear resistance, gas barrier properties, corrosion resistance, strength, light weight, processability, ease of codeposition of flaky carbon into plating, etc., the plating solution additive of the present invention is preferably contained in an amount of 0.1 to 50 mass%, more preferably 0.5 to 30 mass%, of 100 mass% of the total amount of the solution containing the metal compound and the plating solution additive of the present invention.

[0188] The method and conditions for mixing the solution containing the above metal compound with the plating solution additive of the present invention are not particularly limited, and can be carried out in accordance with a conventional method.

[0189] 4. Thin plated films and electrolytic plating methods The plated thin film of the present invention can be formed by plating on a substrate using the plating solution of the present invention in a conventional manner. The plating method is not particularly limited and can be the same as a conventional plating method, but for example, a plating current of 5 A / cm 2 Less than (especially 0.1 to 3A / dm 2 It is preferable to employ an electrolytic plating method in which a current density of 1000 kJ / cm 2 is applied.

[0190] This allows for the production of a thin plated film containing the plating solution additive of the present invention and nickel, copper, zinc, chromium, tin, silver, gold, or the like. In other words, the plating solution additive of the present invention (particularly, flaky carbon) can be co-deposited in the thin plated film at about 0.01 to 10 mass % (particularly about 0.02 to 5 mass %). This allows for the thin plated film to be endowed with various properties, such as thermal conductivity (heat dissipation), electrical conductivity, lubricity, abrasion resistance, gas barrier properties, corrosion resistance, strength, light weight, and processability.

[0191] The thickness of the thin plated film of the present invention thus obtained is not particularly limited, but can be, for example, 0.1 to 50 μm (particularly 0.5 to 30 μm). [Example]

[0192] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0193] [Example 1] A mixed liquid was obtained by mixing and stirring 500 g of natural graphite (manufactured by Ito Graphite Industries Co., Ltd.), 250 g of tannic acid (manufactured by Fuji Chemical Co., Ltd.), and 10,000 g of water.

[0194] This mixture was subjected to shearing treatment five times for 30 minutes at 1700 rpm using a ceramic grinder with a radius of 300 mm. The shortest distance of the ceramic grinder was approximately 10 μm.

[0195] These treatments resulted in a uniform and smooth dispersion of flaky carbon. Note that because the extrusion from the device and the device cleaning were performed with water, the carbon content was 2.5 wt %.

[0196] A nickel plating solution was prepared by adding water to 240 g of nickel sulfate, 50 g of nickel chloride, and 30 g of boric acid to make 1 L. 10 g of the above-mentioned flaky carbon dispersion was added to this plating solution to check the dispersibility. As a result, no supernatant was observed even after 20 hours.

[0197] Using this solution, a 50mm square steel test piece was subjected to a bath temperature of 50℃ and a current density of 2A / dm 2 As a result, it was confirmed that flake carbon with a size of 1 to 20 μm was co-deposited in the nickel plating (thickness 10 μm).

[0198] A scanning electron microscope (SEM) image of the obtained nickel-plated surface is shown in FIG.

[0199] [Example 2] Except for adding 50 g of the flaky carbon dispersion, plating was carried out in the same manner as in Example 1. As a result, it was confirmed that flaky carbon having a size of 1 to 30 μm was co-deposited in the nickel plating (thickness 10 μm).

[0200] A scanning electron microscope (SEM) image of the obtained nickel-plated surface is shown in FIG.

[0201] [Example 3] A copper plating solution was prepared by adding water to 200 g of copper sulfate and 50 g of sulfuric acid to make 1 L. 10 g of the flaky carbon dispersion liquid described in Example 1 was added to this plating solution to confirm dispersibility. As a result, no supernatant was observed even after 20 hours.

[0202] Using this solution, a 50mm square steel test piece was subjected to a bath temperature of 50℃ and a current density of 2A / dm 2As a result, it was confirmed that flake carbon with a size of 1 to 10 μm was co-deposited in the copper plating (thickness 10 μm).

[0203] A scanning electron microscope (SEM) image of the obtained copper-plated surface is shown in FIG.

[0204] [Example 4] Except for adding 50 g of the flaky carbon dispersion, plating was carried out in the same manner as in Example 3. As a result, it was confirmed that flaky carbon having a size of 1 to 15 μm was co-deposited in the copper plating (thickness 10 μm).

[0205] A scanning electron microscope (SEM) image of the obtained copper-plated surface is shown in FIG.

[0206] [Example 5] Except for adding 150 g of the flaky carbon dispersion, plating was carried out in the same manner as in Example 3. As a result, it was confirmed that flaky carbon having a size of 1 to 10 μm was co-deposited in the copper plating (thickness 10 μm).

[0207] A scanning electron microscope (SEM) image of the obtained copper-plated surface is shown in FIG.

[0208] [Comparative Example 1] A nickel plating solution was prepared by adding water to 240 g of nickel sulfate, 50 g of nickel chloride, and 30 g of boric acid to make 1 L, and plating was carried out under the same conditions as in Example 1, without adding flaky carbon.

[0209] Comparative Example 2 A mixed liquid was obtained by mixing and stirring 500 g of natural graphite (manufactured by Ito Graphite Industries Co., Ltd.), 250 g of cetyltrimethylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.), and 10,000 g of water.

[0210] This mixture was subjected to shearing treatment five times for 30 minutes at 1700 rpm using a ceramic grinder with a radius of 300 mm. The shortest distance of the ceramic grinder was approximately 10 μm.

[0211] These treatments resulted in a uniform and smooth dispersion of flaky carbon. Note that, because the extrusion from the device and the device washing were performed with water, the carbon content was 2.5 mass %.

[0212] A nickel plating solution was prepared by adding water to 240g of nickel sulfate, 50g of nickel chloride, and 30g of boric acid to make a total volume of 1L. 50g of the above-mentioned flaky carbon dispersion was added to this plating solution to check its dispersibility. As a result, after 1 hour, a supernatant was already visible, making plating impossible. The mixed solution had completely separated after 20 hours.

[0213] Figure 8 shows a photograph of the appearance of the resulting plating solution 20 hours after production.

[0214] Comparative Example 3 A copper plating solution was prepared by adding 200 g of copper sulfate and 50 g of sulfuric acid to water to make 1 L. This copper plating solution was used to plate a 50 mm square steel test piece at a bath temperature of 50°C and a current density of 2 A / dm 2 The plating was carried out for 25 minutes.

[0215] [Experimental Example 1] The friction coefficients of Example 2 and Comparative Example 1 were measured using a surface property measuring instrument TYPE: 14FW (manufactured by Shinto Scientific Co., Ltd.) and compared.

[0216] The dynamic friction resistance was measured using a 10mm diameter stainless steel (SUS) ball, a load of 100g, and a reciprocating distance of 20mm, with 10 reciprocating movements. The results for μk (dynamic friction coefficient) were as follows:

[0217] Example 2: (average) 0.186, (10th time) 0.225 Comparative Example 1: (average) 0.557, (10th time) 0.673.

[0218] The results of Example 2 and Comparative Example 1 are shown in Figures 9 and 10. Dynamic friction resistance was reduced by codepositing flaky carbon.

[0219] [Experimental Example 2] The friction coefficients of Examples 1 and 2 and Comparative Example 1 were measured using a surface property measuring instrument TYPE: 14FW (manufactured by Shinto Scientific Co., Ltd.) and compared.

[0220] The dynamic friction resistance was measured using a 10mm diameter stainless steel (SUS) ball, a 50g load, and a 20mm reciprocating distance, with 50 reciprocating strokes. The results for μk (dynamic friction coefficient) were as follows:

[0221] Example 1: (average) 0.421, (50th time) 0.503 Example 2: (average) 0.237, (50th time) 0.281 Comparative Example 1: (average) 1.092, (50th time) 1.065.

[0222] 11 to 13 show the results of Examples 1 and 2 and Comparative Example 1. It can be seen that adding a very small amount of flaky carbon and co-depositing reduces dynamic friction resistance, and that increasing the amount of flaky carbon added further reduces dynamic friction resistance.

[0223] [Experimental Example 3] The friction coefficients of Examples 4 and 5 and Comparative Example 3 were measured using a surface property measuring instrument TYPE: 14FW (manufactured by Shinto Scientific Co., Ltd.) and compared.

[0224] The dynamic friction resistance was measured using a 10mm diameter stainless steel (SUS) ball, a 50g load, and a 20mm reciprocating distance, with 50 reciprocating strokes. The results for μk (dynamic friction coefficient) were as follows:

[0225] Example 4: (average) 0.303, (50th time) 0.395 Example 5: (average) 0.207, (50th time) 0.219 Comparative Example 3: (average) 0.703, (10th time) 0.753.

[0226] The results of Example 5 and Comparative Example 3 are shown in Figures 14 to 16. It can be seen that adding a very small amount of flaky carbon and co-depositing it reduces the dynamic friction resistance, and that increasing the amount of flaky carbon added further reduces the dynamic friction resistance.

Claims

1. The carbon nanotube includes flaky carbon having a thickness of 1 to 100 nm and an organic compound having a hydrophilic group and a hydrophobic group having a high affinity with carbon, The flaky carbon includes an organic compound having a hydrophilic group and a hydrophobic group having high affinity with carbon in an amount of 0.1 to 100 parts by mass per part by mass of the flaky carbon, the hydrophilic group is a phenolic hydroxyl group and / or a polyoxyethylene group, the hydrophobic group is an aryl group, the organic compound having a hydrophilic group and a hydrophobic group having high affinity for carbon is polyoxyethylene naphthyl ether and / or a plant polyphenol, The plant polyphenol is at least one selected from the group consisting of persimmon tannin, tannic acid, catechin, anthocyanin, isoflavone, chlorogenic acid, ellagic acid, curcumin, and caffeic acid. Plating solution additive.

2. 2. The plating solution additive according to claim 1, wherein the hydrophobic group is an aryl group having two or more aromatic rings.

3. 3. The plating solution additive according to claim 1, which is a dispersion in a solvent containing water.

4. 4. The plating solution additive according to claim 3, wherein the content of the water is 25% by mass or more, based on 100% by mass of the total amount of the plating solution additive.

5. The plating solution additive according to any one of claims 1 to 4, A plating solution containing at least one metal compound selected from the group consisting of nickel compounds, copper compounds, zinc compounds, chromium compounds, tin compounds, silver compounds and gold compounds.

6. 6. The plating solution according to claim 5, wherein the plating solution contains 0.001 to 5 mass % of the flaky carbon, with the total mass of the plating solution being 100 mass %.

7. 7. The plating solution according to claim 5, wherein the organic compound having a hydrophilic group and a hydrophobic group having a high affinity for carbon is contained in an amount of 0.001 to 10% by mass, with the total amount of the plating solution being 100% by mass.

8. The method for producing the plating solution according to any one of claims 5 to 7, a step of mixing the solution containing the metal compound with the plating solution additive; A manufacturing method comprising:

9. A plating solution additive according to any one of claims 1 to 4, and at least one metal selected from the group consisting of nickel, copper, zinc, chromium, tin, silver, and gold, having a thickness of 0.1 μm to 50 μm; Thin plated film.

10. 1. An electrolytic plating method comprising: The plating solution according to any one of claims 5 to 7 is used, and ２ Electroplating method, wherein a current density of less than

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