JP2010269516A - Writing utensil filled with conductive aqueous ink, silver wiring circuit, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a writing utensil filled with aqueous ink containing silver nanoparticles with an average particle diameter of 2 to 50 nm which can easily form a wiring circuit on a substrate in an arbitrary shape, and to provide a wiring circuit of high conductivity and low resistivity formed by drawing using the utensil. <P>SOLUTION: The writing utensil is filled with conductive aqueous ink. The conductive aqueous ink is characterized by including: a compound X comprised of an amino group in a polyethyleneimine (a) of 500 to 50,000 in the number average molecular weight combined with a polyethylene glycol (b) of 500 to 5,000 in number average molecular weight; or a compound Y comprised of an amino group in a polyethyleneimine (a) of 500 to 50,000 in number average molecular weight combined with a polyethylene glycol (b) of 500 to 5,000 in number average molecular weight and epoxy resin (c); silver nanoparticles Z with an average particle diameter of 2 to 50 nm counted in a transmission electron microscope photograph; and a water-based solvent. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention provides a writing instrument filled with a conductive aqueous ink containing silver nanoparticles having an average particle diameter of 2 to 50 nm, which can easily form a wiring circuit on a substrate having an arbitrary shape, and the same. The present invention relates to a silver wiring circuit having high conductivity and low resistivity, and a method for manufacturing the same.

  In order to develop highly integrated, highly functional, small, and thin information devices, it is necessary to develop semiconductor microfabrication technology and at the same time have highly reliable mounting technology that supports the microfabrication. The component technology of the mounting technology includes the production of fine metal particles and the fine wiring / connection technology using the paste as a paste. The combination with printing technology such as inkjet has been attracting attention. Technology development is underway (for example, see Patent Document 1).

  Before manufacturing a wiring board by applying printing technology such as inkjet, which is a relatively large device, it is necessary to repeat the design and prototyping of the wiring circuit to examine the suitability of the circuit. There is a lack of technology to enable this.

  As an example of a writing instrument filled with conductive ink, for example, a conductive sign pen that can be detected with a conductive pen used for learning materials or the like, specifically, a film of 3 MΩ / □ or less is provided. (For example, refer to Patent Document 1). However, this level of coating is not at a level that can be applied to a wiring circuit used as a conductive material, and needs further improvement.

  In addition, a pen-shaped filling container having a mechanism for suppressing excessive discharge of the filled conductive aqueous ink is provided (see, for example, Patent Document 2). The conductive ink used in Patent Document 2 may be any commercially available one, and merely shows the possibility of forming a wiring circuit. Further, in Patent Document 2, the shape of the filling container is limited in order to adjust the discharge amount of the conductive water-based ink. For this reason, in view of replenishment and replacement of the filled conductive aqueous ink and productivity, there is a need to provide a writing instrument filled with the conductive aqueous ink that is easier to use.

JP-A-7-276878 JP 2005-178857 A

  In view of the above situation, the problem to be solved by the present invention is that a conductive aqueous ink containing silver nanoparticles having an average particle diameter of 2 to 50 nm, which can easily form a wiring circuit on a substrate having an arbitrary shape. And a wiring circuit having a high conductivity and a low resistivity formed by using the writing instrument.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a segment that contributes to the development of high dispersibility and a segment that can immobilize metal fine particles or reduce metal ions. A writing instrument filled with a conductive aqueous ink containing stabilized silver nanoparticles, obtained by reducing a silver compound in an aqueous medium in the presence of a compound having at least two kinds of segments, has its storage stability. The present invention has been completed by discovering that the wiring circuit drawn using this can exhibit high conductivity, while being excellent in the properties and recyclability.

  That is, the present invention is a writing instrument filled with a conductive water-based ink, the writing instrument comprising a compound having a specific structure, silver nanoparticles, and an aqueous solvent, and using this Provided are a wiring board and a manufacturing method thereof.

  The writing instrument obtained in the present invention has a silver nanoparticle surface when silver ions are reduced to silver nanoparticles by the reducing ability, coordination bond strength, electrostatic interaction, etc. of the polyethyleneimine chain in the compound used. The aqueous dispersion of silver-containing independent particles having a certain size formed by coordination of the compound is filled with the compound, and the storage stability is excellent. In the case of this writing instrument, particularly a fountain pen, the aqueous dispersion can be easily replenished and replaced, and can be obtained by simply replacing the ink part of a commercially available fountain pen.

  In addition, the silver wiring board of the present invention is obtained by drawing using the writing instrument of the present invention and is formed on various solid substrates, and the glass transition temperature of the solid substrate is It may be insufficient for heat resistance of 180 ° C. or lower, and of course, a flat substrate, of course, a rod-shaped, tube-shaped, fibrous, or three-dimensional molded product subjected to microfabrication On the other hand, it is a highly conductive wiring board with good adhesion.

The figure of the white silver line written in the black cowhide using the fountain pen with which the aqueous ink of the silver containing independent particle | grains obtained in Example 1 was filled. The photograph after 30-minute heating for 120 degreeC on the stripe silver wire written on PET film using the fountain pen with which the aqueous ink of the silver containing independent particle | grains obtained in Example 1 was filled. The photograph after 30-minute heating for 180 degreeC on the stripe silver wire written on PI film using the fountain pen with which the aqueous ink of the silver containing independent particle | grains obtained in Example 1 was filled.

  The writing instrument of the present invention is a writing instrument filled with a conductive aqueous ink, and the conductive aqueous ink has a number average molecular weight in an amino group in polyethyleneimine (a) having a number average molecular weight of 500 to 50,000. Is a compound (X) formed by bonding polyethylene glycol (b) having a molecular weight of 500 to 5,000, or an amino group in polyethyleneimine (a) having a number average molecular weight of 500 to 50,000, and the number average molecular weight is 500. Compound (Y) obtained by bonding polyethylene glycol (b) of ˜5,000 and epoxy resin (c), and silver nanoparticles having an average particle diameter of 2 to 50 nm determined from a transmission electron micrograph (Z ) And an aqueous solvent.

  The silver nanoparticle (Z) in the present invention means that the particle diameter observed in a transmission electron micrograph is on the order of nanometers, and the shape does not need to be a perfect sphere. . Moreover, the number average molecular weight of each segment which comprises a compound (X) or a compound (Y) is a polystyrene conversion value measured by gel permeation chromatography (GPC).

  In the polyethyleneimine chain (a) constituting the compound (X) and the compound (Y) used in the present invention, the ethyleneimine unit in the chain can be coordinated with silver and its ions, and further reduction of silver ions Is a polymer chain that stabilizes and holds silver nanoparticles (Z). The structure has an ethyleneimine unit as the main repeating unit, and may be linear or branched, and may be either a commercial product or a synthetic product.

  The conductive water-based ink used in the present invention is an aqueous dispersion of silver-containing independent particles formed by coating the surface of the silver nanoparticles (Z) with the compound (X) or the compound (Y). preferable. That is, as will be described later, silver obtained by removing the compound (X) or the compound (Y) that does not contribute to stabilization by covering the surface of the raw materials and silver nanoparticles (Z) used during the reduction reaction, etc. It is preferable that the contained independent particles are dispersed in a desired aqueous solvent from the viewpoint that the obtained wiring circuit becomes highly conductive.

  The size of the silver-containing independent particles is not limited to the molecular weight of the compound (X) or the compound (Y) used or the molecular weight of the polyethyleneimine (a), but each component constituting the compound (X) or the compound (Y), That is, polyethylenemin (a), hydrophilic segment (b) to be described later, compound (Y), and the structure and composition ratio of linear epoxy resin (c) to be described later and the type of silver used as a raw material. to be influenced. In order to increase the content of silver nanoparticles (Z) in the silver-containing independent particles, it is preferable to use a branched polyethyleneimine chain.

  A commercially available branched polyethyleneimine is branched by a tertiary amine and can be used as a raw material for the compound (X) or the compound (Y) used in the present invention. From the viewpoint of obtaining silver-containing independent particles having a preferable particle diameter, which can provide silver-containing independent particles excellent in storage stability and conductive aqueous inks that are aqueous dispersions thereof, the degree of branching is (tertiary amine) / (all In terms of the molar ratio of (amine), the degree of branching is preferably in the range of (1 to 49) / (100), and more preferable range of branching degree in view of industrial production, availability, etc. Is (15-40) / (100).

  If the average molecular weight of the polyethyleneimine (a) portion is too low, the retention ability of the silver nanoparticles (Z) by the compound (X) or the compound (Y) tends to be lowered, and the storage stability becomes insufficient. If it is too high, the silver-containing independent particles are likely to become large, and the storage stability of the redispersed aqueous dispersion (conductive aqueous ink) may be hindered. Therefore, the storage stability of the obtained silver-containing independent particles and dispersion thereof is more excellent, and the number average molecular weight is from the viewpoint of increasing the content of silver nanoparticles (Z) in the particles. It is in the range of 500 to 50,000, preferably in the range of 1,000 to 40,000, and most preferably in the range of 1,800 to 30,000.

  When the molecular weight of polyethylene glycol (b) is dispersed in a hydrophilic organic solvent, the dispersion stability may be deteriorated if the molecular weight is too low, and the dispersion may be aggregated if the molecular weight is too high. Moreover, from the viewpoint of increasing the silver content in the silver-containing independent particles, the number average molecular weight of the polyethylene glycol (b) portion is 500 to 5,000, and more preferably 1,000 to 3,000.

  Polyethylene glycol (b) may be a commercially available product that is generally used, or a synthetic product. Further, it may be a copolymer with other hydrophilic polymer. Examples of the hydrophilic polymer that can be used at this time include polyvinyl alcohol, polyacrylamide, polyisopropylacrylamide, and polyvinylpyrrolidone. From the viewpoint of increasing the silver content in the obtained silver-containing independent particles, even when a copolymer is used, the overall molecular weight is preferably in the range of 500 to 5,000.

  In the compound (Y) used in the present invention, a linear epoxy resin (c) is further bonded as a hydrophobic segment. By including a structure derived from the linear epoxy resin (c) in the compound (Y), when the compound (Y) is redispersed in an aqueous medium, due to the strong association force between the molecules or between the molecules, A stable aqueous dispersion can be obtained by forming a core of micelles, forming stable micelles, and incorporating silver nanoparticles (Z) therein.

  The linear epoxy resin (c) can be used without particular limitation as long as it is generally commercially available or can be synthesized. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, naphthalene type tetrafunctional epoxy resin, tetramethylbiphenyl type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy Resin, dicyclopentadiene-phenol addition reaction type epoxy resin, phenol aralkyl type epoxy resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin type epoxy resin, xanthene type epoxy resin described in JP-A No. 2003-201333, etc. Or two or more of them may be mixed. Among these, it is preferable to use a bisphenol A type epoxy resin from the viewpoint of excellent adhesion to the substrate when drawing using the resulting writing instrument. In addition, these epoxy resins may be used as the raw material of the compound (Y) as they are, and further may be those modified in various ways according to the structure of the target compound (Y). For example, a part of the epoxy group in the epoxy resin (c) is previously ring-opened with a compound having an aromatic ring having an interaction with a metal to form a more stable silver-containing independent particle and an aqueous dispersion thereof. You can also.

  Further, the molecular weight of the linear epoxy resin (c) is not particularly limited. However, when redispersed in a hydrophilic organic solvent, dispersion stability is deteriorated if it is too low, and micelles are formed if it is too high. The number average molecular weight of the linear epoxy resin (c) is usually 100 to 100 from the point that aggregation is considered and the silver content in the solid content of the silver-containing independent particles can be easily increased. It is preferably 200,000, particularly preferably 300 to 100,000.

  Although it does not specifically limit as a manufacturing method of compound (X) and compound (Y) used by this invention, The thing by the following method is preferable from the point which can synthesize | combine a compound as designed easily.

  As described above, a commercially available or synthesized polyethyleneimine (a) can be suitably used. First, the case where a branched polyethyleneimine chain is used will be described.

  Since the terminal of the branched polyethyleneimine is a primary amine, the terminal of polyethylene glycol (b) can be used in the present invention by pre-modifying and reacting with a functional group that reacts with the primary amine. Compound (X) can be synthesized. The functional group that reacts with the primary amine is not particularly limited. For example, aldehyde group, carboxy group, isocyanate group, tosyl group, epoxy group, glycidyl group, isothiocyanate group, halogen, acid chloride, sulfonic acid Examples include chloride. Among them, a carboxy group, an isocyanate group, a tosyl group, an epoxy group, and a glycidyl group are advantageous in terms of production methods such as reactivity and ease of handling, and are preferable functional groups.

  In addition, the functional group may not be a functional group that directly reacts with the primary amine, but may be any functional group that can be reacted with the primary amine by various treatments. For example, polyethylene glycol having a hydroxy group may be used. For example, it may be reacted with a polyethyleneimine chain by a technique such as glycidylation. Furthermore, after performing the process which converts the primary amine of a branched polyethyleneimine chain | strand into the other functional group which can react with the polyethylene glycol which has a functional group, these are made to react and synthesize | combine a compound (X). Is also possible.

  When the polyethyleneimine chain (a) is a linear polyethyleneimine chain, a polymer compound is obtained by first synthesizing a polyacylated ethyleneimine chain by living polymerization, and subsequently introducing polyethylene glycol. Examples include a method of hydrolyzing an ethyleneimine chain to form a linear polyethyleneimine chain.

  Further, the synthesis method for the compound (Y) used in the present invention has already been provided by the present inventor in Japanese Patent Application Laid-Open No. 2006-213877, Japanese Patent No. 4026662, Japanese Patent No. 4026664, etc. You can refer to it.

  The molar ratio (a) when the repeating unit constituting the chain of each component of polyethyleneimine (a) and polyethylene glycol (b) in compound (X) and compound (Y) used in the present invention is 1 mol: ( Although it does not specifically limit as b), From the point which is excellent in the storage stability of the silver containing independent particle | grains obtained, the dispersion stability of the dispersion liquid, and storage stability, (a) :( b) = 1 Is in the range of 1 to 100, and it is particularly preferable that the design is 1: 1 to 30.

  Moreover, when using a compound (Y), when the repeating unit which comprises the chain | strand of each component of a polyethyleneimine (a), polyethyleneglycol (b), and a linear epoxy resin (c) is 1 mol (a ): (B): (c) is not particularly limited, but is usually (a) from the viewpoint of excellent storage stability of the resulting silver-containing independent particles, dispersion stability of the dispersion, and storage stability. ) :( b) :( c) = 1: 1 to 100: 1 to 100, and it is particularly preferable that the design is 1: 1 to 30: 1 to 30.

  The compound (X) and the compound (Y) used in the present invention are separated from the polyethyleneimine (a) in which the silver nanoparticles (Z) can be stably present, in addition to the polyethylene glycol (b), or more linear. It has a structure derived from the epoxy resin (c). As described above, the polyethylene glycol (b) portion exhibits a high affinity with the solvent in the aqueous medium, and the linear epoxy resin (c) portion exhibits a strong associating force in the aqueous medium. Furthermore, when the linear epoxy resin (c) has an aromatic ring, the silver-containing independent particles and the dispersion thereof are further stabilized by the interaction of the π electrons of the aromatic ring with silver. It is thought that it contributes to.

  In addition, the polyethylene glycol (b) -derived structural portion present in the compound (X) and the compound (Y) is concentrated once in a subsequent purification step, and then redispersed in an aqueous medium. It is thought that it contributes to performing efficient rearrangement of the compound (Y) and the silver nanoparticles (Z). That is, since the polyethylene glycol (b) -derived structure is unevenly distributed to the medium side during redispersion, all of the polyethyleneimine (a) -derived structures in the compound are involved in the stable retention of the silver nanoparticles (Z). This will stabilize the silver nanoparticles (X) with the minimum necessary compound (X) or compound (Y), and the silver content in the resulting silver-containing independent particles will be reduced. It can be inferred that it can be increased. Therefore, it is considered that the silver-containing independent particles obtained in this way are covered with a polyethylene glycol (b) -derived structure, and the powder is redispersed to prepare a dispersion. In this case, it is considered that the re-dispersion is easy and the stability is excellent without using a new dispersant.

  The first step in the production of the conductive aqueous ink used in the present invention is a step of dissolving or dispersing the compound (X) or the compound (Y) in an aqueous medium, that is, water or a mixed solvent of water and a hydrophilic organic solvent. It is. In the case of polyethyleneimine (a), polyethylene glycol (b), and further compound (Y), the solubility and dispersibility in aqueous media differ depending on the combination of epoxy resin (c), but it dissolves uniformly. Or it is necessary to disperse. The hydrophilic organic solvent that can be used here may be any one that can be mixed at least 5 parts by mass with respect to 100 parts by mass of water at 25 to 35 ° C. to obtain a uniform mixed solvent. , Ethanol, isopropyl alcohol, n-propyl alcohol, tetrahydrofuran, dioxane, acetone, methyl ethyl ketone, dimethylacetamide, dimethylformamide, ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, diethylene glycol Glycerin, dimethylsulfone oxide, dioxirane, N-methylpyrrolidone, dimethylimidazolidinone, sulfo Can be exemplified emissions etc., may be used individually or as a mixture of two or more. Various ionic liquids may be used.

  As the use ratio of the compound (X) or the compound (Y) and the aqueous medium, the silver content of the silver-containing independent particles obtained from the viewpoint of easy handling and ease of silver ion reduction reaction. From the viewpoint of improvement, the concentration of the compound (X) or the compound (Y) is preferably 1 to 20% by mass, and more preferably 2 to 15% by mass. At this time, when the solubility / dispersibility of compound (X) or compound (Y) is insufficient, for example, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate Solubility and dispersibility can be adjusted by using a mixed solvent in combination. In order to dissolve or disperse the compound (X) or the compound (Y), usually, the compound (X) or the compound (Y) may be allowed to stand at room temperature or stirred, and may be subjected to ultrasonic treatment, heat treatment or the like as necessary. Further, when the familiarity with the aqueous medium is low due to the crystallinity of the compound (X) or the compound (Y), for example, the compound (X) or the compound (Y) is dissolved or swollen with a small amount of a good solvent. Thereafter, it may be dispersed in a target aqueous medium. At this time, it is more effective to perform ultrasonic treatment or heat treatment.

  After preparing a solution or dispersion of compound (X) or compound (Y), a silver compound is mixed. At this time, from the viewpoint of increasing the silver content in the obtained silver-containing independent particles, compound (X) or It is preferable to use it so that it may become 400-9900 mass parts as silver with respect to 100 mass parts of compounds (Y). Furthermore, it is preferable to mix so that it may become 2-80 mass% as a non volatile matter from a viewpoint which improves productivity by reducing the usage-amount of an aqueous medium, and can control a reductive reaction easily. More preferably, it is used so that it may become 900-9900 mass parts as silver and 3-50 mass% as a non volatile matter with respect to 100 mass parts of compound (X) or compound (Y).

  At this time, as a silver compound that can be used, any silver compound (Z) can be obtained by a reduction reaction. For example, silver nitrate, silver oxide, silver acetate, silver fluoride, silver acetylacetonate, benzoic acid Silver oxide, silver carbonate, silver citrate, silver hexafluorophosphate, silver lactate, silver nitrite, silver pentafluoropropionate, silver perchlorate, silver sulfate, silver chloride, silver bromide, silver iodide, silver sulfite, Examples thereof include silver tetrafluoroborate, silver p-toluenesulfonate, and silver trifluoroacetate. From the viewpoint of easy handling and industrial availability, it is preferable to use silver nitrate or silver oxide.

  In the step, the method of mixing the silver compound with the aqueous medium in which the compound (X) or the compound (Y) is dissolved or dispersed is not particularly limited, and the compound (X) or the compound (Y ) May be a method in which a silver compound is added to a medium in which the solution is dissolved or dispersed, or vice versa, or a method in which mixing is performed while simultaneously charging in another container. A mixing method such as stirring is not particularly limited.

  At this time, in order to accelerate the reduction reaction, it may be heated to about 30 to 70 ° C. as necessary, or a reducing agent may be used in combination.

  The reducing agent is not particularly limited. For example, hydrogen, hydrogenation can be performed because the reduction reaction can be easily controlled and can be easily removed from the reaction system in a subsequent purification step. Boron compounds such as sodium boron and ammonium borohydride, alcohols such as methanol, ethanol, propanol, isopropyl alcohol, ethylene glycol and propylene glycol, aldehydes such as formaldehyde, acetaldehyde and propionaldehyde, ascorbic acid, citric acid and citric acid It is preferable to use acids such as sodium and hydrazines such as hydrazine and hydrazine carbonate. Among these, sodium borohydride, ascorbic acid, sodium citrate and the like are more preferable from the viewpoint of industrial availability and handling.

  The addition amount of the reducing agent is not particularly limited as long as it is an amount necessary for reducing silver ions, and the upper limit is not particularly specified, but it is 10 mol times or less of silver ions. Is preferable, and it is more preferable that it is 2 mol times or less.

  Moreover, the addition method of a reducing agent is not limited, For example, a reducing agent can be dissolved and disperse | distributed and mixed as it is in aqueous solution or another solvent. Further, the order in which the reducing agent is added is not limited, and even when the reducing agent is added to the solution or dispersion of the compound (X) or the compound (Y) in advance, the reduction is performed simultaneously with the mixing of the silver compound. An agent may be added, and further, a method of mixing a reducing agent after several hours have elapsed after mixing a solution or dispersion of compound (X) or compound (Y) with a silver compound. .

  In particular, when using a raw material that does not dissolve or hardly dissolves in an aqueous medium such as silver oxide or silver chloride, a complexing agent may be used in combination. Examples of the complexing agent include propylamine, butylamine, diethylamine, dipropylamine, triethylamine, ammonia, ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, 1,3-diaminopropane, N, N , N ′, N′-tetramethyl-1,3-diaminopropane, triethylenetetramine, methylaminoethanol, dimethylaminoethanol, ethanolamine, diethanolamine, methyldiethanolamine, propanolamine, butanolamine, dimethylaminopropanol and the like. .

  The amount of the complexing agent added is not particularly limited as long as it is sufficient to be coordinated with silver oxide or the like to form a complex, and the upper limit is not particularly specified. It is preferable that it is 20 mole times or less. The method for adding the complexing agent is not limited. For example, the complexing agent can be mixed as it is or dissolved or dispersed in an aqueous solution or other solvent.

  The time required for the reduction reaction in step (1) varies depending on the presence or absence of a reducing agent and the type of compound (X) or compound (Y) used, but is usually 0.5 to 48 hours, from the viewpoint of industrial production. It is preferable to prepare for 0.5 to 24 hours. Examples of the preparation method include a method depending on the heating temperature, the amount of reducing agent and complexing agent added, and the timing thereof.

  Subsequent to step (1), in step (2), the organic nanoparticles are added and then the silver nanoparticles are purified and concentrated. The purification / concentration is not particularly limited, and any of precipitation, centrifugation, dialysis and the like may be used. Among them, purification / concentration of silver nanoparticles by precipitation is preferable. Further, a drying step may be provided in order to completely remove the organic solvent and the like.

  As described above, the method for producing the conductive water-based ink used in the present invention includes a general-purpose equipment under mild conditions such as a spontaneous reduction reaction in an aqueous medium, a general-purpose concentration step, and if necessary, addition of water and drying. In addition, since the solvent to be used can be isolated and separated by a concentration or drying process, it can be reused and is excellent in industrial productivity.

  In the said silver containing independent particle, the silver content rate in this powder solid content can easily obtain 95 mass% or more by the said manufacturing method. By increasing the silver content, it is possible to easily realize a low resistance value, which is an essential physical property of the conductive aqueous ink. That is, it contains silver at such a high content and is excellent in stability. At room temperature, it has not been possible to achieve with silver fine particles and dispersions conventionally provided and conductive water-based inks using these. The desired conductivity (low resistance value) can be expressed only by drying or heating at a low temperature. In addition, the smaller the average particle diameter of the silver-containing independent particles, the better. However, the silver-containing independent particles obtained above are the average particle diameter of 100 particles randomly extracted from a photograph obtained by TEM observation. The small value which is not found in the conventional ink for writing instruments having a value of 2 to 50 nm is a great feature and has an advantage.

  The silver-containing independent particles obtained in the present invention can be made into a dispersion by redispersing the purified silver-containing independent particles obtained above in various aqueous media. The concentration at this time is not particularly limited, and can be variously adjusted according to the use. The concentration of the independent silver-containing particles in the dispersion is usually from 10 to 70% by mass, and from 20 to 60% by mass. It is preferable from the point of wide application range. The solvent that can be used at this time is not particularly limited. For example, water, methanol, ethanol, isopropyl alcohol, n-propyl alcohol, tetrahydrofuran, dioxane, acetone, methyl ethyl ketone, dimethylacetamide, dimethylformamide, ethylene glycol, propylene glycol , Ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, diethylene glycol, glycerin, dimethyl sulfone oxide, dioxirane, N-methylpyrrolidone, dimethylimidazolidinone, sulfolane, etc. Two or more kinds may be mixed and used. The redispersion method is not particularly limited, and the solid silver-containing independent particles can be added while stirring the solvent, or the solvent can be added to the solid silver-containing independent particles.

  The silver-containing independent particles or the aqueous dispersion prepared as described above can be used as a conductive aqueous ink in combination with other compounds as necessary. In particular, by using the compound (II) having a functional group capable of reacting with a nitrogen atom in the polyethyleneimine (a) in combination, a conductive aqueous ink that can be sintered at a lower temperature can be obtained. The mixing method is not particularly limited, and for example, the compound (II) can be mixed as it is or dissolved or dispersed in an aqueous solution or other solvent.

  The compound (II) can be used without particular limitation as long as it is a commercially available or synthesizable compound. Specifically, the compound (II) reacts with a nitrogen atom in the polyethyleneimine (a) to produce an alcohol. Aldehyde compounds, epoxy compounds, acid anhydrides, carboxylic acids, inorganic acids and the like that form amide bonds, form amide bonds, and form quaternary ammonium ions. For example, formaldehyde, acetaldehyde, propionaldehyde, acrolein, benzaldehyde, cinnamaldehyde, perylaldehyde, ethylene oxide, propylene oxide, butylene oxide, 2,3-butylene oxide, isobutylene oxide, 1-methoxy-2-methylpropylene oxide, butyric acid-glycidyl Glycidyl methyl ether, 1,2-epoxyhexane, 1,2-epoxyheptane, 1,2-epoxyoctane, 1,2-epoxydecane, 1,2-epoxydodecane, 1,4-butanediol diglycidyl ether, 1,2-epoxy-5-hexene, 1,2-epoxy-9-decene, 2-phenylpropylene oxide, stilbene oxide, glycidyl methyl ether, ethyl glycidyl ether, Tyl glycidyl ether, glycidyl isopropyl ether, tert-butyl glycidyl ether, allyl glycidyl ether, glycidyl phenyl ether, benzyl glycidyl ether, glycidyl stearate, epoxy succinic acid, 1,5-hexadiene diepoxide, 1,7-octadiene diepoxide 2,2-bis (4-glycidyloxyphenyl) propane, ethylene glycol diglycidyl ether, neopentyl glycol glycidyl ether, acetic anhydride, maleic anhydride, citraconic anhydride, diacetyl-tartaric anhydride, phthalic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 1-cyclohexene-1,2-dicarboxylic anhydride, o-acetyl-malic anhydride, (2-methyl-2-propenyl) succinic acid Anhydride, 1,2-naphthalic anhydride, 2,3-naphthalenedicarboxylic anhydride, 2,3-anthracene dicarboxylic anhydride, 2,3-dimethylmaleic anhydride, 3-methylglutaric anhydride, 3-methylphthalic anhydride, 4-methoxybenzoic anhydride, 4-methylphthalic anhydride, benzoic anhydride, succinic anhydride, butyl succinic anhydride, decyl succinic anhydride, dodecyl succinic anhydride, Hexadecyl succinic anhydride, octadecyl succinic anhydride, octadecenyl succinic anhydride, isooctadecenyl succinic anhydride, tetradecenyl succinic anhydride, nonenyl succinic anhydride, trimellitic anhydride, butyric anhydride, Propionic acid anhydride, heptanoic acid anhydride, decanoic acid anhydride, n-octanoic acid anhydride, nonanoic acid anhydride, oleic acid Water, valeric anhydride, palmitic anhydride, phenoxyacetic anhydride, pivalic anhydride, stearic anhydride, crotonic anhydride, diglycolic anhydride, glutaric anhydride, exo-3,6- Epoxy-1,2,3,6-tetrahydrophthalic anhydride, itaconic anhydride, formic acid, acetic acid, propionic acid, ascorbic acid, citric acid, tartaric acid, maleic acid, fumaric acid, succinic acid, oxalic acid, benzoic acid , P-toluenesulfonic acid, glucuronic acid, hyaluronic acid, gluconic acid, hydrogen peroxide, phosphoric acid, nitric acid, nitrous acid, boric acid and the like may be used alone or in combination of two or more. Also good.

  The amount of the compound (II) to be added is not particularly limited, but is generally from about 0.1 to the ethyleneimine unit in the polyethyleneimine (a) from the viewpoint of excellent storage stability of the obtained conductive aqueous ink. It is preferably in a range of 1 to 5 times molar equivalent, and more preferably 0.25 to 1 times molar equivalent.

  Compounding the compound (II) having a functional group capable of reacting with a nitrogen atom in the polyethyleneimine (a) changes the surface charge of the silver nanoparticles (Z), promotes dispersion stabilization in the solvent, and When the solvent is removed, the polyethyleneimine chain bonded to the compound having a functional group capable of reacting with a nitrogen atom in the polyethyleneimine is detached from the surface of the silver nanoparticle, whereby the melting point of the conductive aqueous ink is lowered. Therefore, since the silver nanoparticles (Z) are fused without performing the decomposition / removal of the protective agent by heating as conventionally performed, sintering at a low temperature becomes possible.

  Further, the above-mentioned silver-containing independent particles of the present invention themselves have good dispersibility in various media, and can be redispersed without using other dispersants, but more storage stability / dispersion When using a conductive water-based ink with excellent stability, improving the film-forming property on a plastic substrate that has a poor correlation with metals, or improving the adhesion of the coating film, It is preferable to use the conductive polymer (III) in combination.

  The hydrophilic polymer (III) is not particularly limited. For example, polyoxyethylene, polyoxypropylene, polyvinyl alcohol, partially saponified polyvinyl alcohol, polyethylene glycol, polyethyleneimine, polypropyleneimine, polyhydroxyethyl acrylate, polyoxyethylene Hydroxyethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, polyacetylethyleneimine, polyacetylpropyleneimine, polypropionylethyleneimine, polypropionylpropyleneimine, polyacrylamide, polyisopropylacrylamide, polyvinylpyrrolidone, polyacyloxazoline, polyethyl Polymers such as oxazoline, polypropyloxazoline, or the above Examples include graft polymers and block polymers composed of two or more polymer chains selected from limers. From the viewpoints of adhesion to plastic substrates and dispersion stability of conductive aqueous inks, polyethylene glycol, polyethyleneimine , Polyvinyl alcohol, amino (meth) acrylate, polyvinylpyrrolidone, polyoxazoline, and a reaction product of polyethylene glycol and polyethyleneimine are preferably used.

  Furthermore, the component that can be mixed as an additive in the conductive water-based ink is not particularly limited, and the surface is smoothed such as various conductive material components, components that improve the affinity and adhesion to electronic materials, and the like. Or the component which controls an unevenness | corrugation, the solvent which has various boiling points, a viscosity regulator, various polymers other than the said hydrophilic polymer, a ceramic, a coupling agent, a crosslinking agent, etc. can be mentioned.

  The conductive water-based ink used in the present invention is obtained by adding the above-mentioned various additives to a dispersion containing silver-containing independent particles obtained by the above-described method. The dispersion may be performed by a stirring method using an apparatus such as an ultrasonic method, a mixer method, a three-roll method, or a ball mill method. In order to obtain a conductive aqueous ink having a good dispersion state, it is possible to perform dispersion by combining a plurality of methods among these dispersion methods.

  The writing instrument of the present invention is not limited to its shape and discharge mechanism as long as it is filled with the above-described conductive aqueous ink, and can be applied to sign pens, ballpoint pens, fountain pens, and the like. Among these, in the case of a fountain pen that applies the capillary phenomenon to an ink ejection mechanism, ink replenishment and replacement are preferable because they are easy to replenish and replace the cartridge. Conventionally provided conductive water-based inks have a large particle size of the conductive material (metal powder, carbon powder, etc.) contained therein, and thus the conductive material is likely to precipitate during storage. Due to the difficulty of uniform discharge, it can be applied only to a writing instrument having a special discharge function as in Patent Document 2. In the present invention, as described above, by using the conductive aqueous ink excellent in storage stability, the silver nanoparticles (Z), which is a conductive material, can be discharged uniformly at the same time as the medium. Therefore, the usefulness of the present application is also high from the viewpoint of easy application to a commercially available writing instrument.

  Moreover, it is necessary to remove the compound (X) or the compound (Y) which coat | covers that the content rate of the silver nanoparticle (Z) in solid content in discharged | emitted conductive water-based ink is high. Therefore, a highly conductive silver wiring circuit can be formed only by removing the aqueous medium, that is, heating at 80 to 180 ° C. This means that it can be suitably used for forming a wiring circuit on paper or a plastic substrate, which has been difficult to apply conventionally.

  The plastic base material is not particularly limited as long as it can draw the conductive water-based ink. The shape can be a film, sheet, plate, or a three-dimensional molded product, such as a simple shape or a complicated shape engraved, etc. It can be suitably applied to the material. Substrates having various surface shapes such as a smooth surface, an embossed surface, and a complex uneven surface can be used as the shape of the substrate surface. As the material, a base material made of an organic material such as a polymer, a base material made of a hybrid material in which an inorganic material such as glass, metal, or ceramic is mixed can be used.

  Examples of the polymer include polyethylene, polypropylene, polycarbonate, polyester, polystyrene, unsaturated polyester resin, vinyl chloride resin, epoxy resin, phenol resin, melamine resin, urea resin, AS resin, ABS resin, poly (meth) acrylate, Poly (meth) acrylamide, polyvinyl alcohol, vinylidene chloride resin, acetal resin, polyamide, polyurethane, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyimide, polyethersulfone, liquid crystal polymer, polyphenylene sulfide, polysulfone, etc. Organic materials are mentioned. Further, the surface of these base materials may be subjected to corona treatment or the like.

  The water contact angle of the plastic substrate such as polyethylene terephthalate, polyethylene naphthalate, and polyimide is about 70 ° and is hydrophobic. Accordingly, since a hydrophilic solution composition is usually repelled due to poor wettability to the hydrophobic substrate, it is difficult to draw in a good state. However, in the writing instrument of the present invention, even when a hydrophilic dispersion medium is used, the silver nanoparticle (Z) capped with the compound (X) or the compound (Y) as a protective agent interacts with the hydrophobic substrate. It can be drawn in a good state on the hydrophobic substrate.

The conductivity of the silver film produced using the aqueous ink of silver-containing independent particles before being packed into the writing instrument in the present invention is usually 1 × 10 ⁻⁴ Ω · cm or less, more preferably 1 × as an intrinsic volume resistivity. 10 ⁻⁵ Ω · cm or less.

  In addition, the conductive water-based ink used in the present invention exhibits high adhesion to a plastic substrate even when fired at a low temperature of 180 ° C. or lower. Therefore, a flexible plastic substrate or paper substrate having a glass transition temperature of 180 ° C. or lower is particularly preferable. However, it can be suitably used.

  In the present invention, a silver wiring circuit is obtained by heating the solid substrate after drawing with the writing instrument obtained above, but the method is not particularly limited. For example, after drawing, the solvent can also be removed by supplying hot air with a dryer or the like, so that the convenience is also excellent.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “%” represents “mass%”.

In the following examples, the equipment used is as follows.
¹ H-NMR: manufactured by JEOL Ltd., AL300, 300 Hz
Particle size measurement: FPAR-1000, manufactured by Otsuka Electronics Co., Ltd.
TEM observation: JEM-2200FS, manufactured by JEOL Ltd.
TGA measurement: SII Nano Technology Co., Ltd., TG / DTA6300
Plasmon absorption spectrum: manufactured by Hitachi, Ltd., UV-3500
Volume resistivity: Mitsubishi Chemical Corporation, low resistivity meter Loresta EP
DSC measurement: SII Nano Technology Co., Ltd., DSC7200

Synthesis Example 1 [Synthesis Example of Compound (X-1)]
Under a nitrogen atmosphere, 9.6 g of p-toluenesulfonic acid chloride was added to a mixed solution of 20.0 g (10.0 mmol) of methoxypolyethylene glycol [Mn = 2,000], 8.0 g (100.0 mmol) of pyridine and 20 ml of chloroform ( A chloroform (30 ml) solution containing 50.0 mmol) was added dropwise for 30 minutes with ice-cooling and stirring. After completion of dropping, the mixture was further stirred at a bath temperature of 40 ° C. for 4 hours. After completion of the reaction, 50 ml of chloroform was added to dilute the reaction solution. Subsequently, after sequentially washing with 100 ml of 5% hydrochloric acid aqueous solution, 100 ml of saturated aqueous sodium hydrogen carbonate solution and 100 ml of saturated saline solution, it was dried over magnesium sulfate, filtered and concentrated under reduced pressure. The obtained solid was washed several times with hexane, filtered, and dried under reduced pressure at 80 ° C. to obtain 22.0 g of a tosylated product.

The measurement result of ¹ H-NMR of the obtained product is shown below.
¹ H-NMR (CDCl ₃ ) measurement result:
δ (ppm): 7.82 (d), 7.28 (d), 3.74-3.54 (bs), 3.41 (s), 2.40 (s)

  2.0.0 g (0.8 mmol) of 5.39 g (2.5 mmol) of a methoxypolyethylene glycol compound having a p-toluenesulfonyloxy group at the terminal synthesized above and branched polyethyleneimine (manufactured by Aldrich, molecular weight 25,000) Then, 0.07 g of potassium carbonate and 100 ml of N, N-dimethylacetamide were stirred at 100 ° C. for 6 hours under a nitrogen atmosphere. To the resulting reaction mixture, 300 ml of a mixed solution of ethyl acetate and hexane (V / V = 1/2) was added, and after vigorous stirring at room temperature, the solid product was filtered. The solid was repeatedly washed twice with 100 ml of a mixed solution of ethyl acetate and hexane (V / V = 1/2) and then dried under reduced pressure to give a compound in which polyethylene glycol was bound to branched polyethyleneimine (X- 24.4g of 1) solid was obtained.

The measurement result of ¹ H-NMR of the obtained product is shown below.
¹ H-NMR (CDCl ₃ ) measurement result:
δ (ppm): 3.50 (s), 3.05 to 2.20 (m)

Synthesis Example 2 [Synthesis Example of Compound (Y-1)]
Bisphenol A type epoxy resin EPICLON AM-040-P (manufactured by DIC Industrial Co., Ltd., epoxy equivalent 933) 18.7 g (20 m equivalent), 4-phenylphenol 1.28 g (7.5 mmol), 65% ethyltriphenylphosphonium acetate An ethanol solution (0.26 ml, 0.12 mol%) and N, N-dimethylacetamide (50 ml) were reacted at 120 ° C. for 6 hours in a nitrogen atmosphere. After standing to cool, it was dropped into 150 ml of water, and the resulting precipitate was washed twice with methanol and then dried under reduced pressure at 60 ° C. to obtain a monofunctional epoxy resin. The yield of the obtained product was 19.6 g, and the yield was 98%.

The measurement result of ¹ H-NMR of the obtained monofunctional epoxy resin is shown below.
¹ H-NMR (CDCl ₃ ) measurement result:
δ (ppm): 7.55 to 6.75 (m), 4.40 to 3.90 (m), 3.33 (m), 2.89 (m), 2.73 (m), 1. 62 (s)

  A solution of the monofunctional epoxy resin obtained above (3.0 g, 1.5 mmol) and acetone (50 ml) in the compound (X-1) 14.4 g (0.48 mmol) obtained in Synthesis Example 1, methanol 60 ml The solution was added and stirred at 60 ° C. for 2 hours under a nitrogen atmosphere. After completion of the reaction, the solvent was removed to obtain a compound (Y-1) in which polyethylene glycol and an epoxy resin were bonded to branched polyethyleneimine.

Example 1
10.0 g of silver oxide was added to 138.8 g of an aqueous solution using 0.592 g of the compound (X-1) obtained in Synthesis Example 1, and the mixture was stirred at 25 ° C. for 30 minutes. Subsequently, when 46.0 g of dimethylethanolamine was gradually added with stirring, the reaction solution turned black-red and slightly exothermic, but was left as it was and stirred at 25 ° C. for 30 minutes. Thereafter, 15.2 g of a 10% ascorbic acid aqueous solution was gradually added with stirring. Stirring was further continued for 20 hours while maintaining the temperature to obtain a black-red dispersion.

  The obtained dispersion was sampled, and a peak of a plasmon absorption spectrum was observed at 400 nm by measuring a visible absorption spectrum of a 10-fold diluted solution, thereby confirming the formation of silver nanoparticles. In addition, spherical silver nanoparticles were confirmed by TEM measurement. And as a result of measuring silver content in solid using TG-DTA, 97.2% was shown.

  400 ml of a mixed solvent of isopropyl alcohol / hexane (volume ratio 1/1) was added to the dispersion obtained after completion of the reaction and stirred for 2 minutes, and then allowed to stand for 3 hours. The supernatant was removed, and the precipitate was washed again with 200 ml of the mixed solvent and allowed to stand, and then the resulting precipitate was subjected to centrifugal concentration at 1500 rpm for 5 minutes. 20 g of water was further added to the precipitate obtained by concentration, and the mixture was stirred for 2 minutes to remove the organic solvent under reduced pressure. The solid content concentration of the aqueous dispersion after the vacuum treatment was adjusted to 30%, and it was stirred with a disper for 1 hour. Furthermore, it processed with the ultrasonic wave for 30 minutes, and prepared the water-based ink filled with a writing instrument. When a little of this ink was dried at room temperature and TG-DTA measurement was performed, the silver content was 97.4%. Moreover, melting | fusing point calculated | required by differential scanning calorimetry was 140-170 degreeC. When 100 particle diameters of silver nanoparticles that can be observed with a transmission electron micrograph of the ink were randomly extracted and the average value thereof was determined, the average particle diameter was 16.8 nm.

  A film was prepared on glass using the above water-based ink, and after heat treatment at 150 ° C. for 30 minutes, the volume resistivity was measured. As a result, it was 23 μΩcm.

  The water-based ink was filled in a plastic fountain pen (Petit 1, SP-30F-L) manufactured by Parrot. Using that fountain pen, I drew a curve on black leather. FIG. 1 is a photographic image thereof.

  Using the fountain pen, 10 striped silver wires were drawn on a PET film and heated at 120 ° C. for 30 minutes. FIG. 2 is a photograph of the striped silver wire. All the lines showed electrical conductivity in the tester.

  Using the fountain pen, 10 striped silver wires were drawn on a polyimide (PI) film and heated at 180 ° C. for 30 minutes. FIG. 3 is a photograph of the striped silver wire. All the silver wires showed electrical conductivity in the tester.

  The peeling of the silver wire was tested by a method in which the cellophane tape was adhered to the silver wire on the PET and PI film and then pulled at a stretch. None of the silver wires were peeled off.

  Furthermore, when the PET or PI film on which the silver wire was drawn was bent 180 ° 50 times and the conductivity was confirmed by a tester, all the silver wires showed the conductivity.

  After leaving the fountain pen filled with the ink at room temperature for 3 months, writing a straight line, a curve, a letter, etc. again, the pen tip was not clogged, and it was in a state where it could be written smoothly. Moreover, the silver wire written by this showed electroconductivity after heating at 150 degreeC / 30 minutes.

Example 2
When 23.0 g of dimethylethanolamine was gradually added to 77.0 g of an aqueous solution using 0.263 g of the compound (Y-1) obtained in Synthesis Example 2, a little heat was generated. Subsequently, when the reaction temperature was changed to 45 ° C. and gradually added to 5.0 g of silver nitrate, the reaction solution turned black-red. Thereafter, the reaction temperature was set to 50 ° C. and stirred for 4.5 hours to complete the reaction, and a black-red dispersion was obtained.

  The obtained dispersion was sampled, and a peak of a plasmon absorption spectrum was observed at around 400 nm by measuring a visible absorption spectrum of a 10-fold diluted solution, thereby confirming the formation of silver nanoparticles.

  250 ml of a mixed solvent of isopropyl alcohol / hexane (1/1 volume ratio) was added to the dispersion obtained after completion of the reaction and stirred for 2 minutes, and then allowed to stand for 3 hours. The supernatant was removed, and the precipitate was washed again with 200 ml of the mixed solvent and allowed to stand, and then the resulting precipitate was subjected to centrifugal concentration at 1500 rpm for 5 minutes. To the precipitate obtained by concentration, 10 g of water was further added and stirred for 2 minutes to remove the organic solvent under reduced pressure. The solid content concentration of the aqueous dispersion after the vacuum treatment was adjusted to 30%, and it was stirred with a disper for 1 hour. Furthermore, it processed with the ultrasonic wave for 30 minutes, and prepared the ink for filling in a writing instrument. After a little of this ink was dried at room temperature and TG-DTA measurement was performed, the silver content was 96.5%. Moreover, melting | fusing point calculated | required by differential scanning calorimetry was 147-178 degreeC. When 100 particle diameters of silver nanoparticles that can be observed with a transmission electron micrograph of the ink were randomly extracted and the average value thereof was determined, the average particle diameter was 18.8 nm.

  A film was prepared on glass using the above water-based ink, and after heat treatment at 180 ° C. for 30 minutes, the volume resistivity was measured. As a result, it was 22 μΩcm.

  The water-based ink was filled in a plastic fountain pen (Petit 1, SP-30F-L) manufactured by Parrot Co., and 10 striped silver lines were drawn on the PET film, which was heated at 150 ° C. for 30 minutes. All the silver wires showed electrical conductivity in the tester.

  Using the fountain pen, 10 striped silver wires were drawn on a polyimide (PI) film and heated at 180 ° C. for 30 minutes. All the silver wires showed electrical conductivity in the tester.

  The peeling of the silver wire was tested by a method in which the cellophane tape was adhered to the silver wire on the PET and PI film and then pulled at a stretch, but no silver wire was peeled off.

  Furthermore, when the PET or PI film on which the silver wire was drawn was bent 180 ° by 50 times and the conductivity was confirmed by a tester, all the silver wires showed conductivity.

  After the fountain pen filled with the nano silver ink was allowed to stand at room temperature for 3 months, writing a straight line, a curve, a letter, etc. again, the pen tip was not clogged, and it was in a state where it could be written smoothly. Moreover, the silver wire written by this showed electroconductivity after heating at 150 degreeC / 30 minutes.

Claims (7)

A writing instrument filled with conductive aqueous ink,
The conductive water-based ink is a compound (X) in which polyethylene glycol (b) having a number average molecular weight of 500 to 5,000 is bonded to an amino group in polyethyleneimine (a) having a number average molecular weight of 500 to 50,000. ) Or
A compound in which polyethylene glycol (b) having a number average molecular weight of 500 to 5,000 and an epoxy resin (c) are bonded to an amino group in polyethyleneimine (a) having a number average molecular weight of 500 to 50,000. (Y) and
Silver nanoparticles (Z) having an average particle diameter of 2 to 50 nm determined from a transmission electron micrograph,
A writing instrument comprising an aqueous solvent. The writing instrument according to claim 1, wherein the conductive aqueous ink is an aqueous dispersion of silver-containing independent particles obtained by coating the surface of the silver nanoparticles (Z) with the compound (X) or the compound (Y). . The writing instrument according to claim 2, wherein the silver nanoparticle (Z) content in the silver-containing independent particles is 95 mass% or more. The writing instrument according to any one of claims 1 to 3, wherein the conductive aqueous ink has a nonvolatile content of 10 to 60 mass%. The writing instrument according to any one of claims 1 to 4, which is a fountain pen. A silver wiring circuit obtained by drawing on a substrate using the writing instrument according to any one of claims 1 to 5 and drying it. A method for producing a silver wiring circuit, comprising: drawing on a substrate using the writing instrument according to any one of claims 1 to 5; and drying it on a range of 80 to 180 ° C.

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