JP2019108503A - Dispersion liquid for ink and production method thereof, ink containing the dispersion liquid for ink, and printed wiring board and manufacturing method thereof - Google Patents

Abstract

To provide a method for manufacturing a printed wiring board at a low price, to provide an ink for the manufacture of the printed wiring board, to provide a dispersion liquid for ink serving as a material for the ink and to provide a method for producing the dispersion liquid for ink.SOLUTION: A dispersion liquid for ink serves as a material for an ink used for providing a conductive base on a substrate in advance in order to form a conductive circuit on the substrate by electrolytic metal plating and contains at least carbon nanowires having an average fiber diameter of 300 nm or less and an average fiber length of 1 μm to 20 μm, a polyimide and a dispersion medium. A method for producing the dispersion liquid for ink, an ink containing the dispersion liquid for ink, a method for manufacturing a printed wiring board comprising providing in advance a conductive base by using the ink and a printed wiring board manufactured by the manufacturing method are provided.SELECTED DRAWING: Figure 3

Description

The present invention relates to an ink dispersion, which is a material of an ink used to provide a conductive base on the substrate to form a conductive circuit by electrolytic metal plating; a method of producing the ink dispersion; The present invention relates to an ink containing the dispersion for the ink; and a printed wiring board using the ink and a method for producing the same.
More specifically, an ink dispersion in which carbon nanowires having a specific shape are dispersed, and an ink containing the ink dispersion are used to provide a conductive base, and the metal is electroplated thereon to conduct electricity. The present invention relates to a method of manufacturing a printed wiring board for forming an electrical circuit.

  The printed wiring board is manufactured by using a resist to protect only a portion of the circuit that you want to leave the circuit from the substrate provided with a copper foil having a sufficient thickness as a circuit on the entire surface, and then covering with a resist. Subtractive method of removing unexposed exposed parts by etching; exposed part not covered with resist after protecting only the part that is not desired to be a circuit using a resist on the substrate provided with a thin conductive underlayer on the entire surface The circuit is formed by electrolytic copper plating, and then the remaining resist and the underlying conductive underlayer are removed by a semi-additive method; the circuit is coated with a resist on the substrate on which the electroless copper plating catalyst has been applied on the entire surface. It is known that a full additive method for forming a circuit by electroless copper plating an exposed part not covered with a resist after protecting only a part which is not desired to be used.

  However, the subtractive method is wasteful of removing copper having a sufficient thickness once spread over the surface; the semi-additive method has a large number of steps; the full additive method is as a catalyst for electroless copper plating. The palladium (Pd) used is expensive, and finally the catalyst remains on the entire surface of the substrate, and the palladium (Pd) easily shorts the wiring when producing a precision circuit having a rare wiring distance; There is. Furthermore, in any of the above methods, there are also problems such as a large number of processes, a lot of materials being wasted, and a high manufacturing cost.

  As a method of reducing the manufacturing cost, there is a method of forming a circuit with a conductive ink. That is, there is a method of forming a circuit by printing only in the part to be the circuit (only in the necessary part) (for example, Patent Documents 1 to 4, Non-patent Document 1).

In Patent Document 1, a conductive ink using a powder of silver, copper, aluminum, nickel, gold, or graphite as a conductive powder is used to form a circuit in a base sheet, and then a molten resin is pressed into the circuit sheet. There is disclosed a technology for transferring the circuit to a resin to manufacture a printed wiring board.
Patent Document 2 discloses a technology for producing a printed wiring board directly by injecting a conductive ink from a nozzle of an ink jet printer.
However, these techniques do not take into consideration the circuit strength of the conductive ink or the conductivity in the hole.

  In order to increase the strength of the circuit, Patent Document 3 discloses a technique for forming a circuit with a fluid containing conductive material of fine particles, heating to a temperature higher than the melting point of the fine particles and then solidifying it to produce a wiring board. It is done. However, this technique has various problems such as the need for a high temperature heating step.

  As what does not require a heating step, Patent Document 4 discloses that metal ultrafine particles (eg, silver fine particles, etc.) dispersed as metal colloids in water and / or organic solvent, and halogen in the molecule by ionic bonding. The technology which makes a circuit (for example, sodium chloride etc.) which it has are made to act, and forms a circuit on a substrate and manufactures a wiring board is indicated. However, this technique is expensive because all of the circuit is formed of an expensive metal called silver.

  There is also a method of printing the circuit with an ink containing silver fine particles, heating to strengthen the bond between the silver fine particles, and then applying copper plating to increase the thickness of the circuit (Non-Patent Document 1), but expensive Problems such as the use of silver and the need for heating.

  As described above, there are various methods of forming a circuit with a conductive ink as a method of producing a printed wiring board without cost, but using expensive metal, requiring heat treatment, and between conductive particles Connection is weak, the circuit is weak in mechanical strength, the resolution is low, and it is difficult to apply to flexible substrates from the viewpoint of maintaining conductivity, filling conductive materials in the holes such as via holes It is difficult to do (or can not be filled), some of which are applicable, and further improvement is desired.

On the other hand, carbon fibers, sized carbon fibers and carbon fiber reinforced plastics (CFRPs) are light weight and have both toughness and flexibility, so various molded articles can be used as metal substitutes. It is often used for
Among them, the shortest carbon fiber is also referred to as milled fiber, and in general, the average fiber length is 70 μm to 200 μm, and the average fiber diameter is about 10 μm.

CFRP and so-called "carbon fibers" are difficult to process as they become shorter, and are difficult to use because they are easily aggregated, and carbon fibers having a size thinner or shorter than the above-mentioned "milled fibers" are not in reality.
Although there are references in which the fiber diameter and aspect ratio of carbon fibers are described (for example, Patent Documents 5 and 6), carbon fibers having a small fiber diameter or fiber length and a large aspect ratio do not exist in the market. There is no known dispersion in which such carbon fibers are stably dispersed.

As the background, in conductivity, research on nanoparticles such as carbon nanotubes, silver, copper, etc. has progressed, and since they are common, nano-sized carbon fibers were not present for reasons such as being unnecessary You might also say that.
Although it is known that carbon fibers have conductivity, dispersions of carbon fibers having very small average fiber diameter and average fiber length and large aspect ratio are not known, therefore, the dispersions There is no known ink having conductivity (utilization of conductivity) used and no method for producing a printed wiring board using the ink.

JP-A-8-191178 Unexamined-Japanese-Patent No. 2003-289179 Japanese Patent Application Laid-Open No. 11-274671 JP 2008-004375 A JP 2012-188790 A Unexamined-Japanese-Patent No. 2017-066546

https://www.elephantech.co.jp/technology/manufacturing-processes/

  The present invention has been made in view of the above background art, and an object thereof is to provide a method for manufacturing a printed wiring board at low cost. In addition, “ink for forming a circuit on a substrate”, “dispersion for ink to be a material of the ink”, “method for producing the dispersion for the ink” and the like for producing the printed wiring board are provided. It is to be.

  As a result of intensive studies to solve the above problems, the inventor of the present invention has prepared an ink with an ink dispersion containing a carbon nanowire having a specific shape, a specific binder resin, and a dispersion medium. By applying electrolytic metal plating after forming a conductive base on a substrate with the ink, it has been found that a printed wiring board can be manufactured extremely inexpensively and without any problem of corrosion, and the present invention has been completed.

That is, the present invention is an ink dispersion, which is a material of an ink used to provide a conductive base on a substrate in order to form a conductive circuit on the substrate by electrolytic metal plating,
It is an object of the present invention to provide an ink dispersion characterized by containing at least a carbon nanowire having an average fiber diameter of 300 nm or less and an average fiber length of 1 μm to 20 μm, a polyimide, and a dispersion medium.

  Further, the present invention contains the above dispersion liquid for ink and is used to provide a conductive base on the substrate in order to form the conductive circuit on the substrate by electrolytic metal plating. It provides the ink characterized by the above.

The present invention is also a method of producing the above-mentioned dispersion for ink,
The carbon fibers are obtained by dry grinding raw carbon fibers to obtain carbon fibers or preparing dry ground carbon fibers, and then wet grinding the carbon fibers in the dispersion medium using a bead mill. The present invention provides a method for producing an ink dispersion, which comprises dispersing a carbon nanowire dispersion in the dispersion medium while pulverizing, and dissolving a polyimide in the carbon nanowire dispersion.

  In the present invention, the carbon nanowire dispersion liquid contains 1 part by mass or more and 15 parts by mass or less of the dry-pulverized carbon fiber in 100 parts by mass of the dispersion medium, and is wet-pulverized using a bead mill. The present invention provides a method of producing the above-mentioned dispersion for ink, which is obtained by

  Further, according to the present invention, when producing the carbon nanowire dispersion by dispersing the carbon fiber in the dispersion medium while wet-pulverizing using a bead mill, the dispersion medium contains an anionic surfactant. The present invention provides a method of producing the above-mentioned ink dispersion liquid.

  Further, according to the present invention, a conductive circuit is provided on a substrate by using the ink containing the above-described dispersion liquid for ink, and electrolytic metal plating is performed on the conductive substrate to form a conductive circuit on the substrate. And providing a method of manufacturing a printed wiring board.

  Further, the present invention is a printed wiring board as manufactured using the above-described method for manufacturing a printed wiring board, wherein the circuit portion is at least in order from the bottom, the substrate, the conductive base, and the electrolytic metal plating. A printed wiring board characterized by having a layer.

According to the present invention, the above problems and the above problems can be solved, and a printed wiring board can be easily manufactured at extremely low cost.
The invention also provides an ink for producing a printed wiring board at low cost, a "dispersion for ink not requiring an expensive metal material" as a material of the ink, a method for producing the dispersion for the ink, and the like. it can.

As described above, the method of manufacturing a printed wiring board includes a subtractive method, a semiadditive method, a full additive method, a method of forming a circuit by printing only on a portion to be a circuit (only on a necessary portion), and the like.
Among them, the subtractive method, the semiadditive method and the full additive method have the disadvantages as described above. For example, in the full additive method, palladium (Pd), which is used as a catalyst for electroless copper plating, is expensive, and finally, the catalyst remains on the entire surface of the substrate to cause a circuit short.

  In addition, in the “method of forming a circuit by printing”, conventionally, since a dispersed product of metal ultrafine particles (for example, silver fine particles etc.) is used, the material cost in producing a printed wiring board is extremely expensive; In the case of metals, corrosion occurs; That is, in addition to the fact that metals such as silver themselves are expensive, it is expensive to produce metal nanoparticles (ultrafine particles), and the ink containing it is extremely useful as a material for producing printed wiring boards. It was expensive.

According to the present invention, since carbon fiber is used instead of metal, the material cost of the ink itself is low, and the process of producing the dispersion for ink, which is the material of the ink, is also metal nanoparticles (ultrafine particles). Since a delicate chemical process is not required compared with manufacture, an extremely inexpensive ink can be provided in total.
In addition, since carbon fibers (carbon nanowires) do not rust, it is not necessary to consider corrosion prevention as in the case of conductive metal nanoparticles (ultrafine particles). This is also true for the corrosiveness of the "surface of the conductive substrate" provided on the substrate before electrolytic metal plating.

Further, by setting the average fiber diameter and average fiber length of the carbon nanowires in the dispersion liquid for ink of the present invention in the above-described specific range, and further, setting the average aspect ratio in the above-described specific range The dispersibility and the dispersion stability of the carbon nanowire in the “ink dispersion and ink obtained from the ink dispersion” are improved. In addition, the printability on the substrate, the fillability of the holes present in the substrate, the conductivity of the circuit, the conductivity retention of the bent portion when the substrate is bent, the conductivity retention when the conductive base is thinly provided Etc. will be better.
Furthermore, these physical properties can be specifically improved by making the dispersion medium and the binder used for the ink dispersion liquid specific.

  “The above-mentioned“ ink containing silver nanoparticles (silver ultrafine particles) ”, which is known as a method for forming a circuit by printing, is heated after printing the circuit to strengthen the bond between the silver nanoparticles, etc. However, since the carbon nanowires in the ink dispersion of the present invention are made of a carbonaceous material and have the above-described specific shape, the heating step is unnecessary, The cost reduction of printed wiring board manufacture can be achieved by that much.

  In addition, the wettability of the electrolytic metal plating solution to the conductive substrate can be improved by containing a surface affinity improver in the ink dispersion liquid or ink, and plating at the time of electrolytic metal plating (particularly at the start of plating) It is possible to eliminate obstacles related to stickiness etc. By containing the surface affinity improver, the wettability to the electrolytic metal plating solution can be ensured even if the conductive base surface is not subjected to, for example, plasma treatment.

  In addition, the content of carbon nanowires in the ink dispersion must be increased beyond a certain value in order to ensure conductivity, but if doing so, the thixotropy or structure of the "ink dispersion and ink containing the same" The viscosity is increased to make it difficult to produce the ink or to print. Therefore, by containing a thixotropy reducing agent for reducing the thixotropy (for reducing the structural viscosity) of the ink dispersion or the ink containing the ink dispersion, the ink can be suitably produced, and suitable printing is performed. Can.

  The “carbon nanowires having the above-described specific shape” in the ink dispersion liquid of the present invention is obtained by dispersing and dispersing carbon fibers suitably only by wet grinding using a bead mill. Furthermore, carbon nanowires having the above-described specific shape are particularly preferably obtained by the above-mentioned wet grinding, preferably in the presence of an anionic surfactant.

  The ink containing the ink dispersion can fill the holes (through holes, via holes, blind via holes, etc.) on the substrate. By applying electrolytic metal plating on the carbon nanowires and the polyimide-filled holes in the ink of the present invention, sufficient mechanical strength such as adhesiveness can be obtained.

  If the ink containing the dispersion for ink of the present invention is used as an inkjet ink, a screen printing ink or a pressure jet ink, a conductive base is formed by the printing method and drawing method, “direct printing with conductive ink The thickness is not limited as compared with a dry film, a liquid resist or the like used in “the method of drawing”, and therefore, it is possible to obtain the same or more resolution.

  The carbon nanowires dispersed in the ink dispersion liquid of the present invention are closer in shape to silver nanowires and carbon nanotubes than so-called carbon nanofibers (CNF). Therefore, the carbon nanowires in the present invention are chemically structurally graphite, but are close in shape to so-called silver nanowires, so they are suitable as a conductive base for forming a conductive circuit by electrolytic metal plating. is there.

  Generally, copper used for a wiring substrate is said to have a lower electrical resistance than graphite, but it is considered that the surface electrical resistance is greatly affected. On the other hand, when the carbon fiber (graphite) is micronized, the electric capacity is larger than that of the copper which is micronized, and therefore, it is possible to flow a large current even with a thin wiring. Therefore, the ink dispersion liquid of the present invention is particularly useful as a material of wiring of a printed wiring board.

  In the production of the dispersion liquid for ink of the present invention, carbon fibers, carbon fibers subjected to sizing treatment, or CFRP are used as raw materials, and those which are first “dry-pulverized” or “dry-pulverized” are used as raw materials However, as the CFRP, wastes and unnecessary substances can be used, or CFRP products can be used, and if necessary, they can be roughly pulverized and then dry pulverized (used as a raw material). Even when CFRP is used as the starting material in the method for producing a dispersion for an ink according to the present invention, plastics other than carbon fiber itself are substantially removed from the dispersion obtained. He is almost the same regardless of the starting material.

It is a schematic sectional drawing which shows an example of "the electroconductive base obtained by the ink containing the dispersion liquid for inks of this invention", and the "conductive circuit obtained by electrolytic metal plating" formed on it. It is a scanning electron microscope (SEM) photograph of carbon fiber after dry grinding and before wet grinding. (A) Overlapping 500x photo (b) Nonoverlapping 500x photo (c) 2000x photo It is a scanning electron microscope (SEM) photograph of the carbon nanowire currently disperse | distributed to the carbon nanowire dispersion liquid after wet grinding. (A) 500 times the picture (b) 2000 times the picture

  Hereinafter, the present invention will be described, but the present invention is not limited to the following specific embodiments, and can be arbitrarily modified within the scope of the technical idea.

The dispersion liquid for ink of the present invention is a dispersion liquid for ink, which is a material of ink used to provide the conductive base 14 on the substrate 11 in order to form the conductive circuit on the substrate 11 by electrolytic metal plating. And
It is characterized in that it contains at least a carbon nanowire having an average fiber diameter of 300 nm or less and an average fiber length of 1 μm to 20 μm, a polyimide, and a dispersion medium.

<Dispersion liquid for ink>
The ink dispersion liquid of the present invention contains carbon nanowires having an average fiber diameter of 300 nm or less and an average fiber length of 1 μm to 20 μm. Although not limited thereto, more preferably, the average aspect ratio of the carbon nanowires is 3 or more and 200 or less.
In the present invention, the average fiber diameter, average fiber length, average aspect ratio, particle size distribution and the like of carbon fibers and carbon nanowires are measured by the method described in the Examples, and are defined as measured as such.
Here, the average aspect ratio is defined by [average aspect ratio] = [average fiber length] / [average fiber diameter].

<< Carbon Nanowires >>
Here, “carbon nanowire” has a chemical structure of graphite (graphite) and a chemical structure of carbon fiber, and has an average fiber diameter of 300 nm or less and an average fiber length of 1 μm to 20 μm.
Compared with so-called milled fibers having an average fiber length of 70 μm to 200 μm, the average fiber length is short and the average fiber diameter is also thin. Also, as compared with so-called chopped fibers larger than that, naturally, the average fiber length and the average fiber diameter are smaller.
Moreover, although it does not exclude inclusion of things other than "a carbonaceous material such as graphite", which is referred to as a sizing agent, "a plastic derived from CFRP", etc., it is preferable not to substantially contain it.

The average fiber diameter of the carbon nanowires is 300 nm or less, preferably 200 nm or less, more preferably 130 nm or less, still more preferably 100 nm or less, and particularly preferably 80 nm or less. If the upper limit is less than or equal to the above, the effects of the present invention described above will be achieved.
That is, the dispersibility, the dispersion stability are improved, and the conductivity, uniformity, printability, hole filling of the conductive base obtained by printing the ink (containing the dispersion for ink) having the carbon nanowires The conductivity, the conductivity maintenance property of the bent portion of the substrate, the conductivity maintenance property when the conductive base is thinly provided, and the like are improved.
On the other hand, the lower limit of the average fiber diameter of carbon nanowires is not particularly limited, but it is easy to manufacture including pulverization, dispersion, etc .; increase in structural viscosity of ink is suppressed, and carbon in ink is highly concentrated 20 nm or more is preferable, and 30 nm or more is particularly preferable in that the nanowires can be dispersed;

The average fiber length of the carbon nanowires is 20 μm or less, preferably 15 μm or less, more preferably 10 μm or less, still more preferably 7 μm or less, and particularly preferably 4 μm or less. If the upper limit is less than or equal to the above, the above-described effects of the present invention can be obtained, and in particular, the same effect can be obtained as in the case where the upper limit of the average fiber diameter is less than or equal to the above. In addition, even if the thickness of the conductive base is reduced, the length of the carbon nanowire does not become an obstacle.
On the other hand, the lower limit of the average fiber length of the carbon nanowire is preferably 1.2 μm or more, more preferably 1.4 μm or more, still more preferably 1.7 μm or more, and particularly preferably 2 μm or more.
When the lower limit is at least the above, the ink containing the carbon nanowire (containing the dispersion liquid for ink) is printed to form the conductive base, and it is less likely to enter the minute concaves of the substrate and become isolated. The conductivity of the conductive substrate obtained by printing, the conductivity maintenance of the bent portion of the substrate, the conductivity maintenance when the conductive substrate is thinly formed, and the like are improved. In addition, the increase in the structural viscosity of the ink due to the dispersion of the ultrafine carbon nanowires can be suppressed, and the carbon nanowires can be dispersed in the ink at a high concentration. In addition, the production of the dispersion liquid for ink including pulverization, dispersion and the like becomes easy, and the effect of the present invention described above is exerted.

The average aspect ratio of the carbon nanowire is preferably 3 or more and 200 or less, more preferably 4 or more and 100 or less, still more preferably 6 or more and 50 or less, and particularly preferably 8 or more and 30 or less.
When the lower limit of the average aspect ratio of the carbon nanowire is the above, the same effect as the above-mentioned "effect that the upper limit of the average fiber diameter is the above" or "the effect that the lower limit of the average fiber length is the above" Same as the above-mentioned "effect that the lower limit of the average fiber diameter is more than the above" or "the effect that the upper limit of the average fiber length is the above" Play the effect of

<< Dispersion medium >>
As the dispersion medium for the ink dispersion liquid of the present invention, those used as solvents or dispersion media for paints, inks, etc., and those used as solvents or dispersion media for masterbatches when producing paints, inks, etc. Can be mentioned.
Specific examples include, but are not limited to, the following.
Ethylene glycol; ethylene glycol condensates such as diethylene glycol and triethylene glycol; diacetates thereof; ethylene glycol monoalkyl (or phenyl) ethers such as ethylene glycol monoethyl ether and ethylene glycol monophenyl ether; monoacetates thereof; ethylene glycol Ethylene glycol dialkyl (or diphenyl) ethers such as diethyl ether, ethylene glycol diphenyl ether; solvents in which the above "ethylene glycol" is replaced by "diethylene glycol" or "triethylene glycol"; above "ethylene glycol" is replaced by "propylene glycol" Solvents, and the like.

  Also, alcohols such as 3,5,5-trimethylhexanol, 2-ethyl-1,3-hexanediol, 2-methyl-2,4-pentanediol; carboxylic acid esters thereof; cyclic esters such as γ-butyl lactone Carbonates such as propylene carbonate, butylene carbonate, vinyl carbonate; pyrrolidone, N-methyl pyrrolidone (NMP), N-ethyl pyrrolidone, etc. "pyrrolidone which hydrocarbon group may be bonded to nitrogen atom" ("pyrrolidone" And “2-pyrrolidone” is preferable) and the like.

  Further, acetic acid; tetrahydrofuran; hydrocarbons such as benzene, toluene, cyclohexane and xylene; esters such as methyl acetate, ethyl acetate, dioctyl phthalate and aromatic esters; ketones such as acetophenone, methyl ethyl ketone (MEK), cyclohexanone and acetone; Chlorinated solvents such as carbon chloride, chloroform, trichloroethylene and dichloromethane; alcohols such as octylene glycol, acetone alcohol and isopropyl alcohol; carbon disulfide; nitrogen-containing solvents such as pyridine, nitroethane and acetonitrile; dioxane; ε-caprolactone, γ- Lactones such as butyrolactone (GBL); and the like.

  The dispersion media may be used alone or in combination of two or more even if they are in the same system or in different systems.

  Among them, the compatibility with grinding by bead milling is good; the dispersibility of carbon nanowires is particularly suitable; a specific surfactant functions suitably; matching to a polymer substrate such as polyimide, polyepoxy, etc .; And N-methyl pyrrolidone, N-ethyl pyrrolidone, etc. “Pyrrolidone in which the nitrogen atom may be substituted with a hydrocarbon group”, ketone such as methyl ethyl ketone (MEK): lactones such as γ-butyrolactone (GBL); etc. are preferred, and “2-pyrrolidone in which a hydrocarbon group may be bonded to a nitrogen atom” (ie, “hydrogen atom bonded to a nitrogen atom is substituted with a hydrocarbon group More preferred is 2-pyrrolidone "), and N-methyl-2-pyrrolidone (NMP) is particularly preferred.

<< Contents of Carbon Nanowires in Dispersion >>
The content ratio of the carbon nanowires dispersed in the ink dispersion liquid of the present invention is not particularly limited, and may be determined in consideration of the optimum content of the carbon nanowires in the ink obtained therefrom. 1 mass% or more and 99.7 mass% or less are preferable, and 5 mass% or more and 99.5 mass% or less are more preferable, and 10 mass% or more and 99 mass% or more of carbon nanowires are preferable with respect to the total mass of a dispersion medium and carbon nanowire. % By mass or less is more preferable, and 20% by mass or more and 98% or less is particularly preferable.

When the content ratio is at least the above lower limit, the dispersion liquid is not too thin and the dispersion medium is not wasted; the volume of the dispersion liquid is not increased more than necessary; an excess of dispersion medium when the dispersion liquid is used for producing an ink Since it does not contain, the use spreads;
On the other hand, the dispersibility and the dispersion stability of the carbon nanowires are improved when the content ratio is not more than the above-mentioned upper limit; the viscosity, the structural viscosity and the concentration of the dispersion become too high at the time of grinding such as bead milling The properties and dispersibility are improved, and the pulverizing time and dispersing time are shortened; carbon nanowires having a large aspect ratio can be obtained; and so forth.

<< Polyimide >>
The ink dispersion of the present invention contains a polymer compound. The polymer compound contains at least a polyimide. There is no limitation in particular as said polyimide, The thing of a varnish state can be used conveniently. What is marketed as what is called "polyimide varnish" can also be used conveniently.
Polyimides have higher strength and higher heat resistance than ordinary polymers. Further, since the linear expansion coefficient is very low as an organic substance and close to a metal, distortion due to thermal expansion with a metal (wiring) hardly occurs when using a conductive base, and highly accurate wiring processing is possible. Among the polyimides, aromatic polyimides are particularly preferable in view of the above point.

  Examples of other polymer compounds that can be contained in the ink dispersion liquid of the present invention include polyepoxy (precursor) and the like.

<< Affinity improver to electroconductive base surface of electrolytic metal plating solution >>
Furthermore, it is preferable that the ink dispersion liquid of the present invention contain an affinity improver for improving the affinity of the electrolytic metal plating solution to the surface of the conductive base.
When the ink dispersion contains an affinity improver, the wettability and affinity of the electrolytic metal plating solution to the conductive base surface are improved, and the electrolytic metal plating (especially at the start of plating) is performed. Precipitation is suitably carried out on the conductive base surface (in particular, no sticking unevenness occurs). That is, the inclusion of the affinity improver makes it easy for the “electrolytic metal plating solution in which the solvent is water” to be compatible with the surface of the conductive base, and in particular, can prevent the initial failure of electrolytic metal plating in the initial stage.
The affinity improver may be added when the ink is prepared using the ink dispersion as a raw material, not the ink dispersion, but it is preferable to previously mix it in the ink dispersion.

The affinity improver is preferably a polymer or an oligomer containing an acidic group in the molecule, more preferably the acidic group is an anion (salt structure) with a carboxyl group, and the counter cation is ammonium Particular preference is given to ions. Examples of the ammonium include primary to quaternary ammonium. In addition, the affinity improver is preferably a polymeric surfactant (including an oligomer).
Specifically, a polymer surfactant in which the carboxyl group of the (meth) acrylic acid (co) polymer is an ammonium salt is most preferable.

  Specific examples thereof include, but are not limited to, BYK 191 and BYK 9077 manufactured by Big Chemie Japan Ltd .; 合成 -6712 manufactured by Toa Gosei Co., Ltd .; and the like.

<< Ink dispersion liquid or ink thixotropy reducing agent >>
Furthermore, it is preferable to add a thixotropy reducing agent to the ink dispersion liquid of the present invention for reducing the thixotropy of the ink dispersion liquid or the ink containing the ink dispersion liquid (for reducing structural viscosity).
When the thixotropy reducing agent is contained in the dispersion for ink, the thixotropy or structural viscosity of the dispersion for ink is reduced, and the ink can be easily manufactured by adapting to various applications (printing method) It will be). In addition, when the thixotropy reducing agent is contained in the ink dispersion, the thixotropy reducing agent is also contained in the ink using it as a raw material, but especially when doing so, "too high thixotropy or structural viscosity" is an obstacle. In the printing method, the printing becomes easy using the ink.

The thixotropy reducing agent may be added when the ink dispersion is prepared as a raw material, not the ink dispersion, but it is preferable to previously blend it in the ink dispersion.
In the present invention, in order to ensure the conductivity of the conductive base, the content of carbon nanowires in the ink dispersion or in the ink must be increased to a certain value, but if so, the size of the carbon nanowires Because of the small size (or because of the special shape), the thixotropy (structural viscosity) of the dispersion is increased. Therefore, the increase inhibition of thixotropy (structural viscosity) is important in the present invention.

  The specific substance (chemical structure) of the thixotropy reducing agent and the (particularly) preferable range thereof are the same as the above-described affinity improver.

<< Preferred Affinity Enhancer / Tyxotropy Reducer >>
In the present invention, it is particularly preferable that the above-mentioned affinity improver and / or the above-mentioned thixotropy reducing agent is a polymeric surfactant in which the carboxyl group of the (meth) acrylic acid (co) polymer is an ammonium salt. Here, the above-mentioned "()" shall mean both the case where there is description in a parenthesis, and the case where there is nothing.
When the dispersion liquid for ink of the present invention contains an affinity improver or a thixotropy reducing agent, it may contain either or both of them. When both are contained, the affinity improver and the thixotropy reducing agent may be different from each other or identical.

  In the dispersion liquid for ink of the present invention, the compound contained and having a function as an affinity improver often has a function as a thixotropy reducing agent. Therefore, it is particularly preferable that the compound which is an affinity improver and a thixotropy reducer is a polymer surfactant in which the carboxyl group of the (meth) acrylic acid (co) polymer is an ammonium salt.

Examples of the ammonium salt include primary to quaternary ammonium salts.
Further, the copolymerization ratio of (meth) acrylic acid (ammonium salt) unit in the case of (meth) acrylic acid copolymer is not particularly limited, but is preferably 1 to 50 mol%, and 2 to 40 mol%. The mole% or less is more preferable, and 4 mole% or more and 30 mole% or less is particularly preferable.
There are no particular limitations on copolymerization components other than the (meth) acrylic acid (ammonium salt) unit in the case of the (meth) acrylic acid copolymer, but (meth) acrylic ester, styrene, (anhydride) maleic acid, etc. are mentioned Be

<Method of producing dispersion for ink>
The “method for producing a dispersion for ink” of the present invention is the method for producing a dispersion for ink as described above, wherein the raw material carbon fiber is dry-ground to obtain carbon fiber, or the dry-ground carbon fiber is used. Then, the carbon fibers are dispersed in the dispersion medium while being pulverized by wet pulverizing the carbon fibers in the dispersion medium using a bead mill, thereby producing a carbon nanowire dispersion, the carbon nano A polyimide is dissolved in a wire dispersion.
The carbon nanowires in the dispersion liquid are preferably pulverized so that the average fiber diameter is 300 nm or less and the average fiber length is 1 μm or more and 20 μm or less, preferably, the average aspect ratio is 3 or more and 200 or less. While dispersing in the dispersion medium.
The carbon nanowire dispersion liquid of the said shape can be manufactured for the first time only by grinding and dispersing by the above method.

<< Carbon fiber as raw material >>
In the present invention, the above-mentioned "raw carbon fiber" as a raw material includes carbon fibers which have been subjected to sizing treatment; carbon fiber reinforced plastics (hereinafter abbreviated as "CFRP"); carbon fiber reinforced carbon composite Materials: Carbon fibers in which 90% by mass or more according to JIS standard is a carbonaceous substance; carbon fiber single substance or carbonaceous substance single substance; so-called so-called carbon fibers;

The CFRP may be a prepreg obtained by causing carbon fiber to be contained in a matrix resin in a matrix resin, which is heated under pressure in an autoclave, or a molded by heating using a microwave or the like.
According to the particularly preferred method for producing a dispersion for ink of the present invention, "carbon fibers" such as CFRP are longitudinally loosened and the average fiber diameter is reduced by bead milling in the presence of an anionic surfactant. Because it can be used, it is particularly preferable to use CFRP as the above-mentioned "carbon fiber" as a raw material, in order to make full use of the features of the present invention.

  Most of the “substance other than carbon fiber single” contained in the raw material carbon fiber is transferred to the dispersion medium in the process of wet grinding, and little or no residue remains in the dispersed carbon nanowire. However, the present invention does not exclude the case where the substance remains / adheres to the carbon nanowires. The above "transfer into the dispersion medium" may be, for example, when it is dissolved in the dispersion medium; when it is finely dispersed or lumped and dispersed; when it is suspended or separated in the dispersion medium;

  In the “production method of dispersion for ink” of the present invention, first, raw carbon fibers are dry-ground or dry-ground carbon fibers are prepared. That is, although (raw material) carbon fiber may be dry-ground (renewed), or carbon fiber which has already been dry-ground may be obtained and used, it is possible to use raw carbon fiber before bead mill processing described later. Dry grinding is preferred.

The “raw carbon fiber”, which is a raw material before dry grinding, may be chopped fibers, milled fibers, etc. crushed to a certain extent, or may be roughly crushed if large CFRP etc. are required. In addition, it may be a waste material or CFRP (which is roughly crushed) which has become unnecessary.
Examples of “CFRPs that are no longer needed” include those that are no longer needed for commonly used and sold CFRPs, CFRPs that are wastes, and CFRPs that have come out as prototypes (including failed products) by manufacturers etc. Be Specifically, but not limited to, for example, golf club shafts; tennis racquet frame materials; fishing rods; car frames and various parts; plane wings and various parts; Parts; cases of musical instruments, portable items, etc .;

  "Carbon fiber" is a bread-based (PAN-based) carbon fiber obtained by carbonizing acrylic fiber at high temperature, but is a pitch-based (PITCH-based) carbon fiber obtained by carbonizing pitch at high temperature Although it may be used, pitch-based (PITCH-based) carbon fibers are preferred because of its excellent conductivity, that the carbon nanowires of the above-mentioned shape are easily obtained in the present invention, and carbon nanowires having a large aspect ratio are easily obtained. Is preferred.

<< dry grinding >>
In the present invention, dry grinding is first performed, and as the dry grinding, pneumatic grinding using "air flow grinding machine such as cyclone mill; jet mill; etc.";"crusher mill, pin mill, cutter mill, hammer" Mills, axial flow mills, etc. “rotational impact grinding, roll grinding, medium grinding, stone grinding, cutter grinding” and the like can be mentioned. Among them, pneumatic pulverization using a cyclone mill, jet mill or the like is particularly preferable as the dry pulverization in the present invention.
In the air flow type pulverization by a cyclone mill, an air flow is generated by rotation of an impeller (rotor blade), and an object placed in the air flow is dryly crushed. Further, the air flow grinding by the jet mill is to dry the object by making the object collide with the collision plate.

When crusher mill, pin mill, cutter mill, hammer mill, axial flow mill etc. are used for dry grinding, it is difficult to make the average fiber diameter and average fiber length sufficiently small (while keeping the cost down), fiber diameter and fiber length Distribution is too broad, particularly tailing to larger ones.
On the other hand, in the air flow type pulverization using a cyclone mill, jet mill or the like, the above-mentioned problems do not occur, and the average fiber diameter, average fiber length and their distribution preferred for subsequent wet pulverization using a bead mill Particle size distribution).

  An apparatus marketed can also be used conveniently as a cyclone mill. As a commercial product, for example, Cyclone mill manufactured by Shizuoka Plant Co., Ltd., Cyclone mill manufactured by Shizuoka Machine Co., Ltd., super powder mill manufactured by Nishimura Machinery Co., Ltd., tornado mill manufactured by Mitaka Industry Co., Ltd., Furukawa Sangyo Co., Ltd. A Dream Mill manufactured by Systems Co., Ltd. can be mentioned.

The structure of the above-mentioned cyclone mill is not particularly limited, but it has one or more impellers, and it is mainly intended that the objects to be crushed are collided and crushed by the swirling air flow generated by the impellers. It is particularly preferable from the viewpoint of easily achieving the effects by using the air flow crusher; very little metal contamination; and the like.
The impellers may be rotated in the same direction or in opposite directions, respectively.

  Although there is no particular limitation, it is possible that the air flow crusher has a classification function inside, and the classified coarse powder can be crushed again inside and the classified fine powder can be taken out. Particularly preferred in view of obtaining a narrow distribution for removing coarse powder. The classification function is not particularly limited, but is preferably a cyclone classification function from the viewpoint of high classification ability.

  The ambient temperature or setting temperature in the case of using a cyclone mill is not particularly limited and may be in accordance with the method of use of the apparatus, but is preferably 0 ° C. or more and 50 ° C. or less, particularly preferably 5 ° C. or more and 35 ° C. or less . The impeller rotational speed in the case of using a cyclone mill may be in accordance with the method of use of the apparatus used, but is preferably 4000 rpm or more and 20000 rpm or less, and particularly preferably 8000 rpm or more and 15000 rpm or less.

  A commercially available apparatus can also be suitably used as a jet mill. Examples of commercially available manufacturers include Seishin Enterprise Co., Ltd., Hosokawa Micron Corporation, Nippon Pneumatic Mfg Co., Ltd., Nisshin Engineering Co., Ltd., and the like.

The ambient temperature or setting temperature in the case of using a jet mill is not particularly limited and may be in accordance with the method of use of the apparatus used, but is preferably 0 ° C. or more and 50 ° C. or less, particularly preferably 5 ° C. or more and 35 ° C. or less .
Also, the jet injection pressure or injection speed may be in accordance with the method of use of the apparatus used, but most preferably, compressed air at 20 ° C. and 6 bar (0.6 MPa) is used as a grinding gas, and a 500 m / s nozzle The spouting speed is most preferred. The preferred range is ± 20% of the above value, and particularly preferred is ± 10% of the above value.

The above-mentioned "carbon fiber" which is a raw material in the present invention is not particularly limited, but it is preferable to dry-pulverize it to an average fiber length of 70 μm or less and then wet-pulverize described later.
By subjecting dry grinding to an average fiber length of 70 μm or less and then wet grinding, the average fiber diameter, average fiber length, shape distribution, etc. of the carbon nanowires in the dispersion for ink can be in the above essential range or preferred It is easy to fit in the

The average fiber length is preferably 70 μm or less by dry grinding, more preferably 5 μm to 60 μm, still more preferably 10 μm to 50 μm, and particularly preferably 15 μm to 40 μm.
If the upper limit is larger than the above, the average fiber diameter of the carbon nanowire may hardly become 300 nm or less finally even if the condition of the wet grinding is adjusted by wet grinding using a bead mill which is the next step, or the final In some cases, the average fiber diameter of the above (more preferable or particularly preferable) carbon nanowires is difficult to be obtained. In addition, even if the conditions of the wet pulverization are adjusted, the average fiber length and average aspect ratio of the carbon nanowires may hardly fall in the above-mentioned ("more preferable" or "particularly preferable") range. .

  On the other hand, if the lower limit is too small (or smaller than the above), the average fiber length of carbon nanowires can not exceed the lower limit after wet grinding, so finally the average fiber length and average aspect ratio of carbon nanowires In some cases, it is difficult to be in the range described above ("more preferable" or "particularly preferable"). In particular, the average fiber length and the average aspect ratio of the final carbon nanowire may be too small.

  By dry grinding alone, it is difficult to reduce the average fiber diameter in the first place, and it is difficult to grind so as to increase the average aspect ratio, and if the average fiber diameter is forcibly reduced by dry grinding, the average fiber length becomes short. Although the final aspect ratio after wet pulverization may not easily fall within a suitable range, the average fiber diameter after dry pulverization is preferably 3000 nm or more, and particularly preferably 5000 nm or more and 15000 nm or less.

The average aspect ratio after dry pulverization is not particularly limited, but is preferably 10 or less, more preferably 7 or less, and particularly preferably 5 or less.
Depending on dry grinding, it is difficult to make the average aspect ratio larger than the upper limit. That is, it is difficult to reduce the average fiber diameter to such an extent that the average aspect ratio can be larger than the upper limit.
The ink dispersion of the present invention may be finalized by dry grinding, even if it has a relatively large average fiber diameter or a relatively small average aspect ratio, or by leaving it to a specific wet grinding later. As described above, it has been found that suitable "small average fiber diameter and large average aspect ratio" can be obtained.

  In the method for producing a dispersion liquid for ink according to the present invention, it is particularly preferable that the average fiber diameter of “carbon fiber after dry pulverization” before wet pulverization is 3000 nm or more and the average aspect ratio is 10 or less .

<< Wet grinding >>
Wet grinding is performed after dry grinding, wherein the dry grinding contains the dry ground carbon fiber in the dispersion medium and bead milling (preferably in the presence of an anionic surfactant) According to the shape (average fiber diameter, average fiber length, preferably average aspect ratio) of a predetermined carbon nanowire. By bead milling, a dispersion in the form of the novel carbon nanowire in the present invention can be obtained.
That is, finally, carbon fibers are converted into carbon nanowires having an average fiber diameter of 300 nm or less and an average fiber length of 1 μm to 20 μm, and further described in the section of <Ink Dispersion><< Carbon Nanowires >> (Can be made) of carbon nanowires in the shape of (more preferable or particularly preferable).
It goes without saying that another process may be interposed between dry grinding and wet grinding. Examples of the "other processing" include pre-mixing, pre-mixing, and the like.

<<< Method, Equipment, Conditions of Wet Grinding >>>
In wet grinding, bead milling is performed using a bead mill. As a result, novel carbon nanowire dispersions, dispersions for inks, and inks having carbon nanowires of a specific shape as described above are obtained for the first time.
The conditions for bead milling are adjusted so as to obtain the above-described specific average fiber diameter, average fiber length, preferably an average aspect ratio carbon nanowire (dispersion liquid) and a dispersion liquid for ink. The conditions for bead milling described below are extremely important in order to obtain carbon nanowires of the above-described shape by finally pulverizing carbon fibers after dry pulverization, and the combination of the respective conditions in bead milling can be easily selected. It is not a natural range.

Examples of the material of the beads used in the bead mill include glass, alumina, zircon (zirconia-silica ceramic), zirconia, metal (steel) and the like, with zirconia and the like being preferable and zirconia being particularly preferable from the viewpoint of hardness and the like.
The bead diameter of the beads used in the bead mill is preferably 0.1 mm or more and 1.5 mm or less, more preferably 0.2 mm or more and 1 mm or less, and particularly preferably 0.5 mm or more and 0.8 mm or less.
If the bead diameter is too large, the number of beads in the bead mill container will decrease and the contact point will decrease, and if it can not be suitably dispersed, the average fiber diameter etc. may not be reduced sufficiently. On the other hand, when the bead diameter is too small, when it can not be suitably dispersed, pulverization may take too long.

The packing ratio of beads used in the bead mill is not particularly limited, but is preferably 45% to 85%, more preferably 55% to 80%, and particularly preferably 65% to 75%.
When the bead filling rate is too small, it is difficult for the carbon fiber to be vertically cracked, and it may be difficult to produce a carbon nanowire with a large aspect ratio. On the other hand, when the bead packing rate is too large, the stirring blade of the bead mill may not be easily rotated.

  The shape of the stirring blade used in the bead mill processing is a propeller type, and since the dispersion has extremely high structural viscosity and thixotropy, the shear rate is increased (the viscosity is not increased), and the stirring property and the grinding property In order to keep the dispersibility properly.

The number of revolutions of the stirring blade (agitator) is not limited depending on the passing length of the stirring blade, but is preferably 500 rpm or more and 2000 rpm or less, more preferably 700 rpm or more and 1500 rpm or less, and particularly preferably 1000 rpm or more and 1200 rpm or less.
The peripheral speed of the tip of the agitating blade (agitator) is not limited depending on the passing length of the agitating blade, but a range which can be calculated from the above-mentioned rotational speed as a diameter of 20 cm is preferable. Specifically, 5 m / s or more and 20 m / s or less are preferable, 7 m / s or more and 16 m / s or less are more preferable, and 9 m / s or more and 13 m / s or less are particularly preferable.

The operation mode of the grinding and dispersion of the bead mill may be either a circulation system or a batch system, but the circulation system is preferred. In the case of the circulation type, since it is not delivered to the container as in the batch type, reagglomeration does not proceed at that time.
When the circulation method is used, the degree of miniaturization changes with the number of passes. For example, if the retention time per pass is increased to 60 minutes at 5000 mL, the particle size distribution will be sharp due to the absence of short paths of the processed material, but the aspect ratio of the carbon nanowire itself may also decrease. is there. Therefore, for example, it is desirable that the circulation rate per pass is preferably 10 minutes to 40 minutes, particularly preferably 15 minutes to 30 minutes, preferably 2 passes or more, particularly preferably 3 passes or more.

The time per pass (continuous operation time), the number of passes, and the total time can be determined by using the device structure, concentration, grinding and dispersion conditions, type of carbon fiber (CFRP), and anionic surfactant. Since it may depend on the type of the anionic surfactant, etc., the dispersion after wet-pulverization is appropriately monitored one by one using a particle size distribution measuring device, a scanning electron microscope (SEM), etc. Is preferred.
When the method for producing a dispersion for ink of the present invention is used, a dispersion in which carbon nanowires having an average fiber diameter of 300 nm or less and an average fiber length of 1 μm to 20 μm, preferably an average aspect ratio of 3 to 200 is dispersed It can be prepared.

The time for wet grinding / dispersion is not particularly limited, and the time per pass (continuous operation time) is preferably 7 minutes to less than 45 minutes, more preferably 10 minutes to 40 minutes, and more preferably 15 minutes to 30 minutes. The following are particularly preferred. When the upper limit is set to the above or less, the average aspect ratio can be increased. Moreover, 20 minutes or more and 180 minutes or less are preferable, and, as for the total time of wet grinding and dispersion | distribution, 60 minutes or more and 90 minutes or less are especially preferable.
The temperature of the dispersion and carbon fibers (carbon nanowires) in bead milling is preferably 0 ° C. or more and 50 ° C. or less, particularly preferably 5 ° C. or more and 35 ° C. or less.

The bead mill in the present invention is a wet bead mill, but may be vertical or horizontal.
Moreover, a bead mill can also use a commercially available apparatus. As a commercially available apparatus, for example, a bead mill manufactured by Ashizawa Finetech Co., Ltd., a Dino Mill of Willie E. Bachkofen (WAB), a bead mill of Imex Co., Ltd., a bead mill of Netti (US) and the like can be mentioned.

<<< surfactant used in bead mill grinding >>>
The wet grinding is preferably performed by bead milling in the presence of an anionic surfactant to disperse simultaneously with the grinding. In a preferred embodiment of the method for producing a dispersion for ink according to the present invention, the carbon fibers are dispersed in the dispersion medium while being wet-pulverized using a bead mill to produce a carbon nanowire dispersion. It is a manufacturing method of the above-mentioned dispersion liquid for ink which contains anionic surfactant in a medium.
The anionic surfactant is preferably a polymeric anionic surfactant ("polymer" also includes an oligomer), and an alkali metal salt of a (co) polymer having an acid group, More preferably, they are ammonium salts, alkyl ammonium salts, alkylol ammonium salts and the like.

Furthermore, the (co) polymer having an acid group is a (co) polymer of (meth) acrylic acid, a (co) polymer of (anhydride) phthalic acid, and a (co) polymer of vinyl benzene sulfonic acid And at least one (co) polymer selected from the group consisting of (co) condensates of naphthalenesulfonic acid is particularly preferable. Here, the descriptions “(co)”, “(meth)”, and “(anhydrous)” indicate that parentheses may or may not be included. Although there is no limitation in particular as a copolymerization monomer in the case of a copolymer, (meth) acrylic acid alkyl ester, (meth) acrylic acid hydroxyalkyl ester, styrene etc. are mentioned.
The (co) condensed product of naphthalenesulfonic acid includes one having a ring bonded by an aldehyde such as formaldehyde. As a co-condensation monomer in the case of co-condensate, phenol, cresol, naphthol and the like can be mentioned.
The counter cation of the (co) polymer having an acid group is more preferably an alkali metal salt, an ammonium salt, an alkyl ammonium salt or an alkylol ammonium salt, particularly preferably a sodium salt or an alkylol ammonium salt is there.
The above-mentioned anionic surfactants may be used alone or in combination of two or more.

  By using an anionic surfactant, and further by using ("more" or "especially") preferred anionic surfactants, the effect of unwinding the carbon fiber is exerted and the average fiber diameter is reduced. It is possible to obtain carbon nanowires (dispersion liquid) of suitable size.

The amount of the anionic surfactant used is not particularly limited, but two or more anionic surfactants may be used with respect to 100 parts by mass of carbon fiber (the same applies to carbon nanowires) to be crushed and dispersed. When used in combination, it is preferably 10 parts by weight or more and 200 parts by weight or less, more preferably 20 parts by weight or more and 150 parts by weight or less, and particularly preferably 30 parts by weight or more and 100 parts by weight or less .
If the amount of the anionic surfactant used is too small, the effect of unraveling the carbon fiber is hardly exhibited, and it becomes difficult to narrow the average fiber diameter without shortening the average fiber length, and the average aspect ratio It may be difficult to obtain large carbon nanowires (dispersion liquid).
On the other hand, when the amount of the anionic surfactant used is too large, the carbon fibers may cause aggregation during melting in the longitudinal direction. As a result, a dispersion liquid in a state in which the carbon nanowires are aggregated is obtained, and thus when applied to an object, the conductivity of the obtained material may be affected.

<<< dispersion medium >>>
The dispersion medium to be used and the preferable dispersion medium are as described above in the section of << dispersion medium >> in <Dispersion for ink>.

<<< Content ratio of carbon fiber in bead mill processing >>>
About the content rate of the carbon nanowire currently disperse | distributed in the dispersion liquid for inks of this invention, it is as above-mentioned and may dilute "the carbon nanowire dispersion liquid immediately after being obtained by wet grinding." It may be concentrated, and is obtained by dissolving at least the polyimide.
However, in the production method of the present invention, that is, in the case of wet grinding using a bead mill, 1 part by weight or more and 15 parts by weight or less of dry ground carbon fiber is contained in 100 parts by weight of dispersion medium. Pulverizing is preferred. It is desirable to wet pulverize by more preferably 2 to 7 parts by mass, still more preferably 3 to 6.5 parts by mass, and particularly preferably 4 to 6 parts by mass.
If the content ratio is too small, the viscosity of the dispersion may be too low and the efficiency of pulverization may decrease. On the other hand, if the content ratio is too large, the viscosity of the dispersion may be too high to make the stirring blade difficult to turn And the efficiency of grinding may decrease.

  The content of carbon nanowires in the carbon nanowire dispersion immediately after preparation of the carbon nanowire dispersion by wet pulverization and dispersion is as described above, and thereafter, the dispersion medium is added to the carbon nanowire dispersion. Or the dispersion medium may be distilled off from the carbon nanowire dispersion liquid for concentration. The diluted solution and the concentrated solution are also the ink dispersion liquid of the present invention.

  The content of carbon nanowires in the “carbon nanowire dispersion liquid” is the dispersion stability, the solubility, mixing property, and stirring property of the polyimide (varnish) at the time of preparation of the dispersion liquid for ink, and the ink for forming the ink. There is no particular limitation as long as the preferred concentration, viscosity, structural viscosity (thixotropy) and the like in the medium are suitable, but 1% by mass to 99.7% by mass is preferable, and 5% by mass to 99.5% by mass is more preferable. 10 mass% or more and 99 mass% or less are more preferable, and 20 mass% or more and 98% or less are especially preferable.

<<< Ink dispersion >>
The present invention is also an ink dispersion characterized in that it is produced by the above-mentioned “Method for producing an ink dispersion”. The mode of the ink dispersion is as described above.

<Ink that is an application of a dispersion for ink>
The ink dispersion is particularly preferably used for ink applications. The present invention is characterized in that it contains the above-mentioned dispersion liquid for ink and is used to provide a conductive base on the substrate in order to form the conductive circuit on the substrate by electrolytic metal plating. It is also an ink that

The method for printing the ink is not particularly limited, and examples thereof include inkjet printing, pressure jet printing, screen printing, electrophotographic printing, offset printing, relief printing, intaglio printing, gravure printing, tampo printing, handwriting printing and the like.
Among them, ink jet printing, screen printing or pressure jet printing is preferable for the application of the present invention to "provide a conductive base on a substrate". “Pressure jet printing” is a method in which ink is jetted from the tip of a needle under pressure of air, nitrogen or the like to print, and is similar to drawing by a dispenser.
Therefore, it is particularly preferable that the ink obtained from the dispersion liquid for ink of the present invention is an ink for ink jet, an ink for screen printing, or an ink for pressure jetting.
Further, in consideration of the drying time of the ink, a UV curable ink (ultraviolet curable ink) is more preferable.

  In the above-mentioned ink, depending on the use and the printing method, the dispersion for ink of the present invention can further contain known compounding agents. As the compounding agent, for example, an antifoamer, a flowability regulator, an organic or inorganic filler, a stabilizer, a dispersing (stabilizing) agent, a binder such as “polyimide etc. other than those described above or additionally described above "Vehicle", surfactants, dispersion media, affinity improvers, leveling agents, plasticizers, colorants, preservatives, structural viscosity and thixotropy imparting agents or inhibitors, and the like.

The content of carbon nanowires in the entire ink is preferably 2% by mass to 50% by mass, more preferably 5% by mass to 40% by mass, and 10% by mass, regardless of the printing method used in any printing method. % Or more and 30% by mass or less is more preferable, and 20% by mass or more and 27% by mass or less is particularly preferable. Among them, in the case of an inkjet ink, a screen printing ink, or a pressure jet ink, 10% by mass or more and 40% by mass or less is more preferable, 15% by mass or more and 35% by mass or less is more preferable, and 20% by mass or more 27 mass% or less is especially preferable.
If the content of the carbon nanowires is too low, even if the carbon nanowires are well dispersed in the polyimide varnish, the contact between the carbon nanowires may increase, and as a result, the conductivity of the conductive base may be lowered. .
On the other hand, if the content of the carbon nanowires is too large, the viscosity may increase, the thixotropy (structural viscosity) may increase, and it may not be possible to satisfactorily print (pattern) the conductive base on the substrate.

<Printed wiring board (production method)>
The present invention forms a conductive circuit on the substrate by providing a conductive base on a substrate using the ink containing the above-mentioned dispersion liquid for an ink, and applying electrolytic metal plating on the conductive base. It is also a manufacturing method of a printed wiring board characterized by doing.
Examples of the printing method (patterning method) for providing a conductive base on a substrate using the ink include those described above, but inkjet printing, screen printing, or pressure jet printing may be used to manufacture a printed wiring board. Is preferable from the viewpoint that suitable (matched) printing is possible.

  The type, material, form, physical properties and the like of the substrate 11 are not particularly limited, and known ones may be used. The substrate 11 may have a plane or holes (through holes, via holes 12, blind via holes 13, etc.) on the substrate, as shown in the schematic cross sectional view of FIG. The ink of the present invention can fill the holes. The conductive base 14 can be provided by filling the holes on the substrate with the ink containing the above-mentioned ink dispersion. Thereafter, electrolytic metal plating is performed, and a metal plating layer can be provided at the opening of the hole to reinforce the conductivity and strength of the hole and the periphery thereof.

The thickness of the conductive base 14 is not particularly limited as long as it is suitable for the subsequent electrolytic metal plating, but 0.1 μm to 8 μm is preferable, and 0.2 μm to 5 μm is more preferable. 0.3 μm or more and 3 μm or less is more preferable, and 0.4 μm or more and 1.5 μm or less is particularly preferable. If it is too thin, it is difficult to ensure conductivity; it can not be differentiated from other methods because it can be thickened; it can not take advantage of low material cost; On the other hand, if the thickness is too thick, it may be wasted; adhesion to the substrate 11 may be difficult to ensure;
Also, in order to fill holes, the conductive base 14 is filled only in the shape of the holes.

The metal in the electrolytic metal plating may be selected depending on the application, but copper, aluminum, nickel and the like are preferable, and copper is particularly preferable in terms of conductivity, plating property, versatility, cost and the like. Therefore, the "electrolytic metal plating" in the present invention is particularly preferably electrolytic copper plating.
The electrolytic metal plating is performed at a current density, a voltage, a temperature or the like which is usually used. When raising it gradually, when lowering it gradually etc., it is carried out by a usual known method.

The thickness of the electrolytic metal plating layer 15 by electrolytic metal plating may be determined according to the application of the printed wiring board 10, but is not particularly limited, but 10 μm to 100 μm is preferable, 18 μm to 70 μm is more preferable, and 25 μm or more 50 micrometers or less are especially preferable.
When the inside of the hole is filled with an ink containing carbon nanowires (when filled with the conductive base 14), preferably 1 μm or more, in order to prevent the filling from falling off by impact. More preferably, electrolytic metal plating of 2 μm or more, particularly preferably 3 μm or more may be performed.

  The present invention relates to a printed wiring board 10 as manufactured using the above-described “method for manufacturing a printed wiring board”, wherein the circuit portion is at least in order from the bottom, the substrate 11, the conductive base 14, and It is also a printed wiring board 10 characterized by having an electrolytic metal plating layer 15 (see FIG. 1). What used the ink containing the carbon nanowire (of a specific shape) as the conductive base 14 is not known. Therefore, the printed wiring board 10 is novel.

  EXAMPLES The present invention will be more specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded.

Measurement example 1
<Average fiber diameter, average fiber length, average aspect ratio>
The average fiber diameter and the average fiber length in the present invention were measured using SEM (No. JSM 7000 series manufactured by Nippon Denshi Co., Ltd.). The average aspect ratio was determined by dividing the average fiber length determined by the above method by the average fiber diameter.

Measurement example 2
<Viscosity of dispersion>
Using a B-type viscometer BM type, no. The # 4 rotor was rotated at 6 rpm and the viscosity at its shear rate was measured. The temperature was 25 ° C.

Measurement example 3
<Surface resistivity of conductive substrate>
The volume resistivity (Ω · cm) was measured according to JlS L6911.

Example 1
<Raw material>
CFRP milled fiber (70 μm to 150 μm in length, 11000 nm in diameter) was used as “carbon fiber” as a raw material. This carbon fiber was pitch based (PITCH based).

<Dry grinding>
Dry grinding was performed on 500 g of the raw material under the following conditions. For dry grinding, a cyclone mill, which is the following air flow grinder, was used.

<< Apparatus and dry grinding conditions >>
Equipment used: Cyclone mill 150S manufactured by Shizuoka Plant Co., Ltd.
Ambient temperature: room temperature (25 ° C)
Impeller rotational speed: 8000 rpm to 15000 rpm
Grinding time: 15 minutes

<< Result >>
As a result, the obtained product has an average fiber diameter of 8000 nm (a distribution width of 90% by volume, 5000 nm to 11000 nm), an average fiber length of 45 μm (a distribution width of 90% by volume, 20 μm to 70 μm), and an average aspect ratio Was 5.6.

<Premixing>
Next, water and surfactant were added under the following conditions, and pre-mixing was performed to stir.

<< Premixing recipe >>
N-methyl-2-pyrrolidone (NMP): 100 parts by mass Dry milled in Example 1 above: 5 parts by mass Alkylol ammonium salt of poly (meth) acrylic acid copolymer as an anionic surfactant: 2 parts by mass

<< Devices and conditions >>
Mixing container: Wet bead mill container below Stirrer: hand drill for explosion proof (with two blades)
Number of revolutions: 500 rpm
Liquid temperature: room temperature (25 ° C)
Stirring conditions: Stop the rotation of the following wet bead mill, and feed the above agitator directly into the material circulation return vessel (hopper) Stirring time: 10 seconds

<< Result >>
At the end of this pre-mixing, due to the anionic surfactant, the "carbon fibers" had already been loosened longitudinally and a reduction in average fiber diameter was observed.
In addition, when the amounts of the two anionic surfactants were doubled respectively, a further decrease of the average fiber diameter was observed. The effects of anionic surfactants, in particular, high molecular weight (including oligomeric) anionic surfactants were confirmed.

<Wet grinding and dispersion treatment>
Next, using the liquid obtained by the above-mentioned preliminary mixing as it was, wet pulverization was performed under the following conditions to prepare a carbon nanowire dispersion liquid.

<< equipment and wet grinding conditions >>
Equipment used: Wet bead mill manufactured by Ashizawa Finetech Co., Ltd. Method: Circulation Container volume: 5 L
Use beads:
Bead material: Zirconia Bead diameter: 0.5 mm
Amount of beads used: 3500 g (bulk 3.5 L)
Bead filling rate: 70%
Rotation speed: Agitator circumferential speed 10m / s
Liquid temperature: room temperature (25 ° C)
Bead milling time: 90 minutes Number of passes: 3 passes 1 pass time: 30 minutes

<< Result >>
The above obtained by wet grinding has an average fiber diameter of 200 nm (90 nm by volume distribution width, 100 nm to 300 nm), an average fiber length of 10 μm (90 volume% distribution width, 5 μm to 15 μm), an average aspect The ratio was 50.

  A carbon nanowire dispersion liquid containing 98 mass% of carbon nanowires is obtained by distilling off NMP, which is a dispersion medium, from the carbon nanowire dispersion liquid immediately after wet pulverization obtained as described above by a conventional method. Was prepared. This is referred to as "carbon nanowire dispersion liquid (A)".

The scanning electron micrograph (SEM photograph) of the carbon fiber after dry-pulverization of Example 1 before wet-pulverization is shown in FIG. 2, and the carbon nanowire dispersed in the carbon nanowire dispersion liquid after wet-pulverization The scanning electron micrograph (SEM photograph) is shown in FIG.
In addition, even if it is a dispersion obtained by wet pulverizing a carbon nanowire dispersion, one obtained by concentrating the dispersion, an ink dispersion obtained using the carbon nanowire dispersion, or an ink obtained using the ink dispersion, The “shape and distribution of the average fiber diameter, average fiber length, etc.” (FIGS. 2 and 3) of the carbon nanowires are all unchanged and identical.

Example 2
<< Condition change of wet grinding >>
In Example 1, without pre-mixing, the same anionic surfactant as in Example 1 was added to the bead mill container in the course of wet pulverization and dispersion treatment and stirred in the same amount as in Example 1 and stirred.
The transition of the average fiber diameter, the average fiber length, and the viscosity in the bead mill wet grinding process (time transition) was as follows. The bead conditions, the stirring conditions, and the like were the same as in Example 1, and the conditions were always fixed even when the time changed. As for the following, as it goes down, time has passed. The description of “average” is omitted.

Bead mill wet grinding starting fiber diameter 5000 nm, fiber length 25 μm, aspect ratio 5.0, viscosity 1300 MPa · s
Fiber diameter: 1000 nm, fiber length: 20 μm, aspect ratio: 20, viscosity: 8000 MPa · s
Here, an anionic surfactant is added, and the chemical dispersion start fiber diameter 1000 nm, fiber length 10 μm, aspect ratio 10, viscosity 700 MPa · s
Fiber diameter: 200 nm, fiber length: 10 μm, aspect ratio: 50, viscosity: 700 MPa · s
Finish of bead mill wet grinding

Example 3
<< Dispersion medium change >>
In Example 1 and Example 2, 100 parts by mass of γ-butyrolactone (GBL) or 100 parts by mass of methyl ethyl ketone (MEK) instead of 100 parts by mass of N-methyl-2-pyrrolidone (NMP) as a dispersion medium The wet pulverization and the dispersion treatment were performed in the same manner as in Example 1 and Example 2 except that they were used.

  Both GBL and MEK were able to obtain a carbon nanowire dispersion as well as NMP. However, in both GBL and MEK, there was a tendency for cohesiveness to increase about 10 minutes after the start of wet pulverization and dispersion, so control of how to proceed dispersion and the amount of surfactant added was more difficult than with NMP.

Example 4
Preparation of Dispersion Liquid for Ink (1) and Formation of Conductive Base>
The carbon nanowire dispersion liquid (A) obtained in Example 1 was added to a polyimide (varnish type).
As a polyimide varnish, Ube Industries, Ltd. product Yupia (registered trademark)-AT (U-varnish-A) [for general heat resistance], and Yupia (registered trademark)-ST (U-varnish-S) [high heat resistance Was used.

The carbon nanowire dispersion obtained in Example 1 was added to 100 parts by mass of each of the above-mentioned polyimide varnishes only in the following parts by mass.
5 parts by mass (0.25 parts by mass of carbon nanowires)
10 parts by mass (0.50 parts by mass of carbon nanowires)
20 parts by mass (1.0 parts by mass of carbon nanowires)
40 parts by mass (carbon nanowires 2.0 parts by mass)
50 parts by mass (2.5 parts by mass of carbon nanowires)
80 parts by mass (carbon nanowires 4.0 parts by mass)

  As a machine for mixing the above, using an automatic mixer AS100, manufactured by As One Co., Ltd., an ink dispersion liquid (1) was obtained by repeating this twice with a stirring time of 14 seconds.

The obtained dispersion liquid for ink was regarded as “ink” as it was, and was applied to a 20 μm polyimide film (entire printing was performed). The coater was coated using a bar coater at a dry film thickness of 12 μm.
After application, the resultant was heated at 140 ° C. for 5 minutes in an oven to obtain a conductive substrate.

  Very good conductivity until the dispersion for ink added with 100 parts by mass of polyimide varnish and 40 parts by mass (containing 2.0 parts by mass of carbon nanowire) of the carbon nanowire dispersion obtained in Example 1 A base (film) was obtained. However, in the case of 50 parts by mass (2.5 parts by mass of carbon nanowires) or more, although the conductive base was formed, some problems occurred in the resin after heating.

<< Result >>
The dispersion for ink obtained above is regarded as "ink" as it is, is applied to a polyimide film, and the conductive base obtained by heating is the volume measured by the measurement method of Evaluation Example 3 in any case. The resistivity was 1.0 × 10 ⁻⁸ [Ω · cm] or less.
The ink dispersion obtained above was able to impart conductivity to the surface of the target polyimide film.

Example 5
Preparation of Dispersion Liquid for Ink (2) and Formation of Conductive Base>
An ink dispersion (2) was produced with the following composition.
Dispersion obtained by concentrating the carbon nanowire dispersion (A) obtained in Example 1 to a carbon nanowire concentration of 99% by mass: 23 parts by mass The same polyimide varnish as that used in Example 4: 67 Mass part N-Methyl-2-pyrrolidone (NMP): 9 parts by mass Polymer surfactant in which the carboxyl group of (meth) acrylic acid (co) polymer is an ammonium salt as an affinity improver and a thixotropy reducer Some BYK-9077 or BYK 191: 1 parts by weight manufactured by Big Chemie Japan Ltd.

When the viscosity was measured according to Measurement Example 2, the viscosity of the ink dispersion liquid (2) was 1000 MPa · s. When the viscosity was set to 1000 MPa · s, thixotropy (structural viscosity) could be suppressed to the extent that there is no problem in printing.
It apply | coated on a polyimide substrate, a SUS board | substrate, a wood board, a PET film, a PE film, and a PVC film so that it might become dry film thickness of 20 micrometers using the automatic coater which has a coating gap (gap).
After coating, those coated on polyimide substrate, SUS substrate and wood board are heated at 115 ° C for 3 minutes in the oven, those coated on PET film, PE film and PVC film are heated at 70 ° C in the oven 6 Heated for a minute.

  Thus, the ink dispersion liquid (2) was regarded as the ink as it was, and the conductive base was provided on various substrates.

<< Result >>
The conductive substrates (films) which can be applied well to all the examined substrates and obtained by heating each have a volume resistivity of 1.0 × 10 ⁻⁸ [Ω · cm measured by the evaluation method 3 ] Was below. The ink dispersion obtained above (even as it was used as an ink) was able to impart conductivity to the surface of the target polyimide substrate.

When the content of the carbon nanowires was reduced to less than 5% by mass, the dispersibility in the polyimide varnish was good but the conductivity tended to be low. Even if it is well dispersed, it is considered that contact defects between carbon nanowires increase. When the content is reduced to improve the dispersibility, it is difficult to obtain a contact between carbon nanowires, so it is desirable for the stability of the contact to make the content of carbon nanowire 15% by mass or more. I understand.
On the other hand, when the content of the carbon nanowires is more than 30% by mass, the viscosity is increased, thixotropy is caused (structural viscosity is increased), and the coating can not be performed.

As mentioned above, as content of carbon nanowire, 20 mass% or more and 27 mass% or less were especially suitable for coater operativity and electroconductivity.
Although the above two types were used as the “affinity improver and thixotropy reducing agent”, the thixotropy and the structural viscosity were all sufficiently low when the viscosity was made optimum (for example, 1000 MPa · s).
The above is suitable for the automatic coater used in this evaluation, but when preparing the ink such as the ink for ink jet, the ink for screen printing, the ink for pressure jetting, etc., using the dispersion liquid for ink (2) The same thing can be said.

Example 6
The ink dispersion (2) obtained in Example 5 was regarded as "ink" as it was, and a conductive base, which was a fine line, was printed on the substrate.
That is, a conductive base circuit with a width of 100 μm on a glass substrate using the model No .: Super CM CMII / SHOT mini 200 Ω manufactured by Musashi Engineering Co., Ltd. which is a “dispenser type printing machine” capable of pressure injection printing. Formed.

<Controller condition>
Discharge method: Air pulse method Discharge pressure setting: 5 to 200 kPa
Ejection time setting: 9999 sec (max)
Vacuum pressure setting: 0 to -20 kPa
<Robot>
Number of control axes: Operating range: XY axis-200 mm, Z axis-100 mm, W axis-0 to 360 °
<Printing conditions>
Discharge pressure: 70 kPa

Further, the ink dispersion liquid (2) obtained in Example 5 was regarded as “ink” as it was, and a conductive base circuit having a width of 5 μm was formed under the following conditions.
<Semiconductor manufacturing / MEMS processing>
SCIVAX Corporation, Model No. X-300BV-TS

After printing (patterning) a conductive base (undried and not cured) as a thin line circuit, the conductive base of the thin line was formed by heating at 115 ° C. for 3 minutes in an oven.
<< Result >>
In each case, the conductive base of the thin line was successfully formed. Thereafter, copper was electrolytically plated on the same using an electrolytic copper plating solution similar to that used in Example 7 described later, but plating was successful.

Example 7
Electrolytic metal plating
In Example 5, a polyimide substrate provided with a conductive base with a thickness of 20 μm after heating was used as a negative electrode, and electrolytic copper plating was performed using an electrolytic metal plating solution of the following composition.
<< Bath composition of electrolytic metal plating solution >>
Copper sulfate (CuSO ₄ · 5H ₂ O): 230 g / L
Concentrated sulfuric acid (H ₂ SO ₄ ): 70 g / L

  The plating apparatus used SanRex KE-15100CT15V specification by Sansha Electric Mfg. Co., Ltd. product. As a plating bath, a 300 mL tank made of acrylic resin was used.

<< Electrolytic metal plating process >>
The following steps were performed. Each process followed a conventional method.
(1) Cleaner conditioner treatment (2) hot water washing (3) water washing (4) acid activation (5) electrolytic copper plating (6) water washing (7) rust prevention treatment (8) drying

A copper plate was used as the material of the positive electrode, and the area of the positive electrode and the negative electrode (“conductive base / polyimide substrate” in Example 5) was 3 cm × 3 cm.
The electroplating voltage started from 3V and was gradually increased to 8V. When electrolytic plating started and copper began to attach, it started from 0.2A and became 0.8A, and when not attached, it was 0A.
When the voltage was raised at the start of electrolytic plating, "burning" occurred. Since the negative electrode side, that is, the conductive base is a carbonaceous substance (carbon nanowire), the electric resistance is higher than that of metal. Therefore, it was necessary to increase the voltage gradually.
The time for forming a 2 μm thick electrolytic copper plating layer on the entire surface of 3 cm × 3 cm size was 20 minutes.

<< Result >>
From the above, the conductive base 14 on which the ink dispersion of the present invention was applied (printed) as it was as the ink was favorably adhered to electrolytic metal plating (in the case of Example 6, electrolytic copper plating). Once attached, the electrolytic copper plating layer can be easily formed to a predetermined thickness because electrolytic copper plating is thereafter performed on the copper surface.
It was considered that the affinity improver contained in the ink dispersion (that is, in the ink) in Example 5 improved the affinity of the electrolytic copper plating solution to the surface of the conductive base.

Example 8
On the polyimide substrate whose schematic cross section is shown in FIG. 1, as in Example 5 and Example 6, however, the above-mentioned dispersion liquid for ink is used as a screen printing ink, and the conductive base 14 is filled and printed with holes. It formed. Thereafter, electrolytic copper plating was performed in the same manner as in Example 7.
As a result, a printed wiring board 10 having a substrate 11, a conductive base 14, and an electrolytic metal plated layer 15 as shown in FIG. 1 could be manufactured.
Carbon nanowires were also filled in the via holes (through holes, through holes) 12 as well as in the blind via holes (non-through holes) 13, and an electrolytic copper plating layer could be suitably formed on the holes (holes). As a result, the carbon nanowires filled in the holes can be reinforced in strength by the electrolytic metal (copper) plating layer on and in the vicinity of the holes.

  Since the dispersion for ink of the present invention and the ink using the dispersion contain carbon nanowires having a specific shape, a printed wiring board can be manufactured at low cost. Therefore, it is widely used in various fields such as the ink production field, the wiring board production field, and the like which are required to improve the performance of the wiring board and to reduce the production cost.

10 printed wiring board 11 substrate 12 via hole (through hole, through hole)
13 blind via holes (non-through holes)
14 Conductive base 15 Electrolytic metal plating layer

Claims (16)

A dispersion liquid for ink, which is a material of ink used to provide a conductive base on a substrate in order to form a conductive circuit on the substrate by electrolytic metal plating,
What is claimed is: 1. A dispersion liquid for ink comprising at least a carbon nanowire having an average fiber diameter of 300 nm or less and an average fiber length of 1 μm to 20 μm, a polyimide, and a dispersion medium.   The ink dispersion liquid according to claim 1, wherein the average aspect ratio of the carbon nanowires is 3 or more and 200 or less.   Further, a thixotropy of an ink containing an affinity improver for improving the affinity of the electrolytic metal plating solution to the surface of the conductive base and / or containing the ink dispersion or the ink dispersion The ink dispersion liquid according to claim 1 or 2, further comprising a thixotropy reducing agent for reduction.   The ink dispersion liquid according to claim 3, wherein the affinity improver and / or the thixotropy reducing agent is a polymer surfactant having a carboxyl group of a (meth) acrylic acid (co) polymer as an ammonium salt.   The ink dispersion liquid according to any one of claims 1 to 4, wherein the dispersion medium contains 2-pyrrolidone in which a hydrocarbon group may be bonded to a nitrogen atom in the molecule.   The ink dispersion according to any one of claims 1 to 5, which is provided with a conductive base on the substrate in order to form the conductive circuit on the substrate by electrolytic metal plating. The ink used in the invention.   The ink according to claim 6, which is an inkjet ink, a screen printing ink, or a pressure jet ink. A method for producing an ink dispersion according to any one of claims 1 to 5, wherein
The carbon fibers are obtained by dry grinding raw carbon fibers to obtain carbon fibers or preparing dry ground carbon fibers, and then wet grinding the carbon fibers in the dispersion medium using a bead mill. And dispersing the dispersion in the dispersion medium to produce a carbon nanowire dispersion, and dissolving the polyimide in the carbon nanowire dispersion.   The carbon nanowire dispersion liquid is obtained by incorporating the dry-pulverized carbon fiber in an amount of 1 part by mass or more and 15 parts by mass or less in 100 parts by mass of the dispersion medium and performing wet pulverization using a bead mill. The manufacturing method of the dispersion liquid for inks of Claim 8.   The method for producing an ink dispersion according to claim 8 or 9, wherein the bead diameter in the bead mill is 0.2 mm or more and 1 mm or less.   8. The method according to claim 8, wherein when the carbon fiber is dispersed in the dispersion medium while being wet-pulverized using a bead mill to produce a carbon nanowire dispersion, the dispersion medium contains an anionic surfactant. The manufacturing method of the dispersion liquid for inks as described in any one of Claim 10.   The method for producing a dispersion liquid for ink according to any one of claims 8 to 11, wherein the raw material carbon fiber is carbon fiber or CFRP subjected to sizing treatment.   A conductive base is provided on a substrate using the ink containing the ink dispersion liquid according to any one of claims 1 to 5, and electrolytic metal plating is performed on the conductive base. A method of manufacturing a printed wiring board, characterized in that a conductive circuit is formed on the substrate.   The method for producing a printed wiring board according to claim 13, wherein the conductive base is provided on the substrate by ink jet printing, screen printing, or pressure jet printing using an ink containing the ink dispersion.   The method for manufacturing a printed wiring board according to claim 13 or 14, wherein a conductive base is provided by an operation of filling the holes on the substrate with the ink containing the dispersion liquid for ink. A printed wiring board as manufactured using the method for manufacturing a printed wiring board according to any one of claims 13 to 15, wherein the circuit portion is at least a substrate, a conductive member in order from the bottom. Printed wiring board characterized by having a metallic base and an electrolytic metal plating layer.

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