JP5521536B2 - Metal film substrate manufacturing method and flexible plastic substrate - Google Patents

Description

  INDUSTRIAL APPLICABILITY The present invention provides a method for producing a metal film substrate and a flexible plastic capable of forming a metal wiring pattern with high adhesion on various base materials such as glass, plastic and metal having poor adhesion by a simple method. Regarding the substrate.

  In recent years, with the miniaturization and high integration of electronic devices, it has been widely attempted to form fine wiring patterns by applying printing techniques such as screen printing and ink jet using conductive ink containing fine metal particles. It is becoming. Among them, a fine conductive wiring pattern using silver and gold conductive inks is formed on various solid substrates such as glass, plastic, and metal having poor adhesion, for example, a sheet or film-like substrate. It is required to form the fine wiring pattern with good adhesion on the material. Conventionally, sputtering, electroless plating methods, vacuum deposition methods, paste coating methods containing glass blito components, and the like have been employed as methods for forming a good adhesion metal film on a substrate, but these methods are expensive. In addition, a relatively large apparatus is required, the process is complicated, and the degree of freedom in changing the wiring pattern is low, and its application is difficult.

  For example, a metal fine particle ink in which metal fine particles having a particle size of 100 nm or less are coated with a polymer or a surfactant and dispersed in water or an organic solvent is used to form a circuit pattern on a substrate using an inkjet apparatus. There is provided a method of drawing and treating this with heat or light to decompose and volatilize the polymer and surfactant to form a desired conductive pattern (see, for example, Patent Document 1).

  However, this method requires a two-step treatment method, ie, heating for volatilization of the solvent and treatment for decomposition and volatilization of the polymer and surfactant used as the protective agent for the metal fine particles. However, a base material with poor heat resistance has a problem that the base material is likely to be deformed during post-treatment. Still, the metal fine particles and the metal film formed by fusing them are only attached to the base material, so they may be peeled off during the post-treatment process, or may have fine cracks. It is difficult to form.

  As a method of forming fine wiring by improving the adhesion to the base material, a method of providing a primer layer on the base material that is an insulating film, an unevenness on the insulating film itself, or an organic group having an anchor effect Various methods have been proposed, such as a method of introducing a glass paste or a paste in which glass bridging or an inorganic oxide is blended in a conductive component such as silver. Among these, as a relatively safe technique in which glass adhesion is improved without using lead-containing glass brid and the like, there is a method using silver powder and polyimide silicone resin (for example, see Patent Document 2).

  In the said patent document 2, when the used polyimide silicone resin is baked at 350-450 degreeC, a part of resin will decompose | disassemble and a vitrified silicone structure will be expressed, and this vitrified silicone structure has favorable adhesiveness with respect to a glass substrate. There is a description that it shows.

  However, the firing step of 350 minutes to 450 ° C. used in Patent Document 2 for 60 minutes is far from the requirement of low temperature of 200 ° C. or less and short-time firing required for recent application development.

  A method using a silver paste having a specific viscosity containing monodispersed silver fine particles coated with a primary amine is also provided (see, for example, Patent Document 3).

  In Patent Document 3, silver fine particles having an average particle diameter of 4 to 20 nm are protected with a primary amine having a relatively high boiling point, and screen printing is directly performed on a substrate using a silver paste containing the silver fine particles. There is an advantage that the manufacturing process is shorter than other methods in that no pretreatment is performed on the base material. The reason why the adhesion is improved by this method is that the primary amine is peeled off from the silver fine particles during the sintering process, and the silver fine particles are fused, and the peeled primary amine reduces and activates the substrate surface. There is a description that it is due to this.

  However, the substrate actually used in Patent Document 3 is an ITO film or polyimide, and the surface of the substrate is activated by application to other plastic substrates having low heat resistance or by the reducing action of primary amines. Cannot be applied to difficult substrates. Moreover, the dispersion medium is an organic solvent having a high boiling point and is volatilized and removed together with the primary amine used as a protective agent for the silver fine particles in the baking process, so that the organic solvent and the primary amine are released into the atmosphere. Including environmental protection and occupational health issues. Furthermore, in Patent Document 3, since the application to screen printing is premised, the viscosity of the silver paste is high, and it is difficult to develop an application to the ink jet method. Since water cannot be used as a medium, it cannot be applied to water-based ink. , It's about versatility.

  In recent years, various kinds of silver fine particles stabilized on the order of nanometers have been proposed, and expectations for mounting technology applications such as formation of conductive electrodes or wiring on a plastic substrate are increasing. However, in order to satisfy the mounting application, adhesion strength that can withstand bending is the most important issue. In other words, the silver coating formed thereon is required to maintain high conductivity until the plastic breaks due to fatigue. In addition, it is generally recognized that it is difficult to form a metal film on a glass substrate, and as described above, even when imparting irregularities to the glass substrate surface or applying a primer, At present, sufficient adhesion is not obtained.

JP 2002-134878 A JP 2007-184153 A JP 2009-016201 A

  The present invention has been made in view of the above-described problems, such as providing a primer layer on the surface of a substrate with poor adhesion, performing special processing or processing that serves as a primer layer, and adhesion. It is not necessary to add a third component to improve the coating, and at high temperatures, it has high adhesion to various substrates such as plastic, glass and metal substrates that have poor adhesion to metal nanoparticles. It is another object of the present invention to provide a metal film substrate manufacturing method and a flexible plastic substrate capable of easily, safely and stably obtaining a conductive pattern and the like.

  As a result of intensive studies to solve the above problems, the inventors of the present invention include a paste containing metal nanoparticles having a specific compound as a protective agent and a dispersion medium, and has high adhesion to a plastic substrate. In particular, a paste in which the cumulant average particle size (average particle size as a result of cumulant analysis at the time of dynamic scattering particle size measurement) is dispersed to 100 nm or less is highly adhesive to glass substrates and metal substrates by a simple method. As a result, the present invention has been completed.

That is, the present invention
(I) Compound (x1) obtained by binding polyethylene glycol (b) having a number average molecular weight of 500 to 5,000 to an amino group in polyethyleneimine (a) having a number average molecular weight of 500 to 50,000, or a number A polyethylene glycol (b) having a number average molecular weight of 500 to 5,000 and a linear epoxy resin (c) are bonded to an amino group in the polyethyleneimine (a) having an average molecular weight of 500 to 50,000. Compound (x2)
A step of directly applying a paste containing the compound (X), the metal nanoparticles (Y), and the dispersion medium (Z) on a plastic substrate,
(II) A method for producing a metal film substrate characterized by having a step of heating the plastic substrate after applying the paste obtained in the step (I) at 60 ° C. to 180 ° C. The present invention provides a flexible plastic substrate having excellent flexibility.

Furthermore, the present invention provides
(I ′) Compound (x1) formed by binding polyethylene glycol (b) having a number average molecular weight of 500 to 5,000 to an amino group in polyethyleneimine (a) having a number average molecular weight of 500 to 50,000, or A polyethylene glycol (b) having a number average molecular weight of 500 to 5,000 and a linear epoxy resin (c) are bonded to an amino group in the polyethyleneimine (a) having a number average molecular weight of 500 to 50,000. Compound (x2)
A paste containing a compound (X), a metal nanoparticle (Y), and a dispersion medium (Z) and dispersed so that the average particle size of the cumulant is 100 nm or less, a glass substrate or a metal group Coating directly on the material,
(II ′) It also provides a method for producing a metal film substrate characterized by having a step of heating the base material after applying the paste obtained in the step (I ′) at 60 ° C. to 200 ° C. is there.

  The present invention forms a highly adhesive metal film on various substrates such as a plastic substrate, a glass substrate having poor adhesion, and a metal substrate, and is based on such plastic, glass, metals and the like. The material may be insufficient in heat resistance, and of course, a flat base material is a base material having an arbitrary shape such as a rod shape, a tube shape, a fiber shape, or a three-dimensional molded product subjected to fine processing. be able to. Further, as a manufacturing method thereof, a specific paste may be applied and dried, and the application method is not particularly limited, so that it can be used in various application fields.

Hereinafter, the present invention will be described in detail.
The method for producing a metal film substrate of the present invention comprises:
A compound (x1) formed by binding polyethylene glycol (b) having a number average molecular weight of 500 to 5,000 to an amino group in polyethyleneimine (a) having a number average molecular weight of 500 to 50,000, or a number average molecular weight. Compound (x2) in which polyethylene glycol (b) having a number average molecular weight of 500 to 5,000 and linear epoxy resin (c) are bonded to an amino group in polyethyleneimine (a) of 500 to 50,000 )
Using a paste containing the compound (X), the metal nanoparticles (Y), and the dispersion medium (Z), and directly applying the paste onto a substrate such as plastic, glass, or metal,
And a step of drying a substrate such as glass, plastic or metal after the paste application obtained in the above step in a low temperature range.

  The metal nanoparticles (Y) in the paste used in the present invention have an average particle diameter (value obtained by randomly extracting 100 particles and taking the average) observed in a transmission electron micrograph of 100 nanometers. It means less than a meter and does not require that the shape be a perfect sphere. Moreover, the number average molecular weight of each segment which comprises compound (X) is a polystyrene conversion value measured by gel permeation chromatography (GPC). Further, the paste has the compound (X) and the metal nanoparticles (Y) as main components in the nonvolatile content, and intentionally contains a third component such as an additive in addition to the dispersion medium (Z). Unless compounded, a nanometer-order complex composed of the compound (X) and the metal nanoparticles (Y) [complex having a structure in which the metal nanoparticles (Y) are protected by the compound (X)] is dispersed in the dispersion medium (Z ). In addition, the cumulant average particle diameter is used as an indication of this dispersion state, and the cumulant average particle diameter is a compound (FPAR-1000, manufactured by Otsuka Electronics Co., Ltd.) measured by a dynamic scattering particle diameter measuring apparatus ( X) is a particle diameter of a composite composed of metal nanoparticles (Y), and means an average particle diameter obtained by cumulant analysis of the measurement result.

  In the polyethyleneimine (a) constituting the compound (X) used in the present invention, the ethyleneimine unit in the chain can be coordinated with the metal and its ions, and further promotes reduction of the metal ions to form metal nanoparticles. (Y) is a polymer chain that stabilizes and holds the metal nanoparticles (Y). 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 size of the complex is not only the molecular weight of the compound (X) to be used, but also the components constituting the compound (X), that is, polyethyleneamine (a), polyethylene glycol (b), and linear epoxy resin ( It is also affected by the structure and composition ratio of c) and the type of metal compound used as a raw material. In the case of polyethyleneimine (a) having the same molecular weight, if the degree of branching is small, the resulting composite has a large particle size, and the particle size tends to decrease as the degree of branching increases. Moreover, in order to raise the content rate of a metal nanoparticle (Y), it is preferable to use a branched polyethyleneimine.

  The commercially available branched polyethyleneimine is branched by a tertiary amine and can be used as a raw material for the compound (X) used in the present invention. From the point of obtaining a metal paste having excellent storage stability, the degree of branching is expressed in terms of (tertiary amine) / (all amines) in a molar ratio of (1-49) / (100). It is preferable, and the more preferable range of the degree of branching is (15 to 40) / (100) in view of industrial production and availability.

  If the number average molecular weight of the polyethyleneimine (a) moiety is too low, the retention ability of the metal nanoparticles (Y) by the compound (X) tends to be low, and the storage stability may be insufficient. If the amount is too large, the compound (X) becomes a huge aggregate, which may hinder the storage stability of the paste. Therefore, in order to improve the ability to immobilize the metal nanoparticles (Y) in the obtained composite and the ability to prevent the composite from becoming too large, the number of the polyethyleneimine (a) The average molecular weight is essential to be 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.

  The polyethylene glycol (b) constituting the compound (x1) and the compound (x2) used in the present invention promotes dispersion stabilization in a hydrophilic solvent as a hydrophilic segment. When the molecular weight of the polyethylene glycol (b) is dispersed in a hydrophilic solvent, the dispersion stability may be deteriorated if the molecular weight is too low, and the composite may be aggregated if the molecular weight is too high. Therefore, in order to obtain a paste with better storage stability, the number average molecular weight of polyethylene glycol (b) must be in the range of 500 to 5,000, and is 1,000 to 3,000. It is preferable.

  The polyethylene glycol (b) may be a commercially available product 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. Even when using a copolymer, it is preferable that the whole molecular weight is the range of 500-5,000 from the point which raises the metal content rate in the obtained paste.

  In the compound (x2) used in the present invention, a linear epoxy resin (c) is bonded as a hydrophobic segment. By incorporating a structure derived from the linear epoxy resin (c) into the compound (x2), when the compound (x2) is dispersed in water or a hydrophilic solvent, a strong association between the molecules or between the molecules. Due to the resultant force, a micelle core can be formed, a stable micelle can be formed, and metal nanoparticles (Y) can be taken therein to obtain a stable dispersion.

  The linear epoxy resin (c) can be used without particular limitation as long as it is generally commercially available or can be synthesized. Examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, xanthene type epoxy resin described in JP-A No. 2003-201333, and the like. The above may be mixed. Among these, it is preferable to use a bisphenol A type epoxy resin from the viewpoint that the obtained paste has excellent adhesion to the substrate. In addition, these linear epoxy resins may be used as the raw material of the compound (x2) as they are, and may further be modified according to the structure of the target compound (x2).

  In addition, the molecular weight of the linear epoxy resin (c) is not particularly limited, but when dispersed in a hydrophilic organic solvent, dispersion stability is deteriorated if it is too low, and micelles are formed if it is too high. There is a possibility of aggregation. From these viewpoints, the number average molecular weight of the linear epoxy resin (c) is usually 350 to 20,000, and preferably 400 to 10,000.

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

  As described above, a commercially available or synthesized polyethyleneimine (a) can be suitably used. First, a case where branched polyethyleneimine 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 (x1) 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, such as reactivity and ease of handling, and are preferred 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 performing various treatments. For example, polyethylene glycol having a hydroxy group may be used. For example, it may be reacted with polyethyleneimine by a method such as glycidylation. Furthermore, the compound (x1) may be synthesized by applying a treatment to convert the primary amine of the branched polyethyleneimine into another functional group capable of reacting with a functional polyethylene glycol and then reacting them. Is possible.

  When the polyethyleneimine (a) is a linear polyethyleneimine, a polyacylated ethyleneimine chain is first synthesized by living polymerization, and then a precursor compound is obtained by introducing polyethylene glycol, and then a polyacylated ethyleneimine Examples include a method of hydrolyzing a chain to obtain a linear polyethyleneimine.

  The method for synthesizing the compound (x2) used in the present invention has already been provided by the present inventors (Japanese Patent Application Laid-Open No. 2006-213877, Japanese Patent Application Laid-Open No. 2008-045024, etc.). A compound having a molecular weight in the range may be synthesized.

  The molar ratio (a) :( b) of the polymer constituting the chain of each component of polyethyleneimine (a) and polyethylene glycol (b) in compound (x1) used in the present invention is not particularly limited. From the viewpoint of excellent storage stability of the obtained silver paste, it is usually in the range of (a) :( b) = 1: 1 to 100, and particularly preferably designed to be 1: 1 to 30.

  When the compound (x2) is used, the molar ratio (a) :( b) :( c) of the polymer constituting the chain of each component of polyethyleneimine (a), polyethylene glycol (b), and linear epoxy resin (c) Although it is not particularly limited, it is usually in the range of (a) :( b) :( c) = 1: 1 to 100: 1 to 100 from the viewpoint of excellent storage stability of the obtained silver paste. In particular, it is preferable to design so as to be 1: 1 to 30: 1 to 30.

  The compound (X) used in the present invention is different from the polyethyleneimine (a) in which the metal nanoparticles (Y) can exist stably, in the compound (x1), in the polyethylene glycol (b) and in the compound (x2). It has a structure derived from polyethylene glycol (b) and linear epoxy resin (c). As described above, the polyethylene glycol (b) portion exhibits a high affinity with the solvent in the hydrophilic organic solvent, and the linear epoxy resin (c) portion exhibits a strong associative force in the hydrophilic organic solvent. Show. Furthermore, when the linear epoxy resin (c) has an aromatic ring, the π electrons of the aromatic ring interact with silver, thereby contributing to further stabilizing the dispersibility of the metal paste. Is also possible.

  In the production method of the present invention, the compound (X) is first dissolved or dispersed in an aqueous medium, that is, water or a mixed solvent of water and a hydrophilic organic solvent. In the case of compound (x1), polyethyleneimine (a) and polyethylene glycol (b), in the case of compound (x2), a combination of polyethyleneimine (a) and polyethylene glycol (b), and linear epoxy resin (c) However, the solubility and dispersibility in an aqueous medium differ, but it is necessary to dissolve or disperse uniformly. 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.

  The use ratio of the compound (X) and the aqueous medium is the compound (X) from the viewpoint of ease of handling, ease of reduction reaction of metal ions, and improvement of the metal content of the resulting paste. ) Is preferably 1 to 20% by mass, and more preferably 2 to 15% by mass. At this time, when the solubility and dispersibility of the compound (X) is insufficient, for example, mixing using ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, etc. The solubility / dispersibility can be adjusted by using a solvent. In order to dissolve or disperse the compound (X), usually, it may be allowed to stand at room temperature (25 ° C.) or stirred, and may be subjected to ultrasonic treatment, heat treatment or the like as necessary. Further, when the compatibility with the aqueous medium is low due to the crystallinity of the compound (X), for example, the compound (X) is dissolved or swollen with a small amount of a good solvent and then dispersed in the target aqueous medium. It is also possible to make it. At this time, it is more effective to perform ultrasonic treatment or heat treatment (about 80 ° C.).

  After preparing the solution or dispersion of compound (X), the metal compound is mixed. At this time, from the viewpoint of increasing the metal content of the resulting paste, 400 parts of metal as the metal with respect to 100 parts by mass of compound (X). It is preferable to use so that it may become -9900 mass parts. 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 a metal and 3-50 mass% as a non volatile matter with respect to 100 mass parts of compounds (X).

  At this time, the metal compound that can be used may be any metal compound (Y) that can be obtained by a reduction reaction, and the type of the metal is gold that facilitates the reduction reaction by the ethyleneimine unit, Silver, platinum, palladium or the like is preferable, and gold or silver is particularly preferable from the viewpoint that a metal film substrate having conductivity can be obtained by applying the obtained paste to the substrate. The raw material is preferably a water-soluble metal compound, but if it is not water-soluble, it should be used if it can be dissolved in an aqueous medium in combination with a complexing agent as described below. Can do. Specific examples of the silver compound include silver nitrate, silver oxide, silver acetate, silver fluoride, silver acetylacetonate, silver benzoate, silver carbonate, silver citrate, silver hexafluorophosphate, silver lactate, silver nitrite, Examples thereof include silver pentafluoropropionate. From the viewpoint of easy handling and industrial availability, silver nitrate or silver oxide is preferably used. Examples of the gold compound include organic gold complexes such as chloroauric acid, bromoauric acid, iodoauric acid, sodium chloroaurate, gold hydroxide, gold oxide, pyridine, or phosphoric acid, and are easy to handle. From the viewpoint of industrial availability, chloroauric acid or sodium chloroaurate is preferably used.

  In the above step, the method for mixing the aqueous medium in which the compound (X) is dissolved or dispersed with the metal compound is not particularly limited, and the medium in which the compound (X) is dissolved or dispersed is not limited. A method of adding a metal compound, a reverse method thereof, or a method of mixing while simultaneously charging in another container may be used. 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 amount of the reducing agent to be added is not particularly limited as long as it is more than the amount necessary for reducing metal ions, and the upper limit is not particularly specified, but it is 10 mol times or less of metal 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 mixed as it is, or it dissolves and disperses | distributes in aqueous solution or another solvent. Further, the order in which the reducing agent is added is not limited, and the reducing agent may be added to the solution or dispersion of compound (X) in advance, or the reducing agent may be added simultaneously with the mixing of the metal compound. Furthermore, after mixing several hours after mixing the solution of a compound (X) or a dispersion liquid, and a metal compound, the method of mixing a reducing agent may be sufficient.

  In particular, when using a raw material that does not dissolve or is difficult to dissolve in an aqueous medium such as silver oxide, gold oxide, silver chloride, and gold 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 form a complex by coordination with a metal oxide or the like, but it is 40 mol times or less of the metal oxide to be used. 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 varies depending on the presence or absence of a reducing agent and the type of compound (X) used, but is usually 0.5 to 48 hours, and is adjusted to 0.5 to 24 hours from the viewpoint of industrial production. Is preferred. 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.

  After carrying out the reduction reaction, the purification step is started. At this time, it is preferable to perform concentration after adding an organic solvent. The concentration method is not particularly limited, and any of dialysis, centrifugation, precipitation, etc. may be used, or they may be used simultaneously. The organic solvent that can be used at this time is not particularly limited, but the viewpoint that the time required for the concentration step can be shortened, the organic solvent can be reused, and the mixture obtained in the previous step is mixed. From the viewpoint of being easy to handle, it is preferable to use an organic solvent having a boiling point of 120 ° C. or lower, preferably 100 ° C. or lower. The amount used is not particularly limited, but it is preferable to mix the mixture obtained in the previous step so that the amount is 1.5 to 5 times, preferably 2 to 3 times. Further, as a concentration method, it is preferable to use a centrifugal separation method from the viewpoint of excellent industrial productivity. In this centrifugal concentration step, in addition to a part of the medium used in the previous step, the purpose is to remove a reducing agent and a complexing agent added as necessary, a counter ion of metal ions, and the like. . Therefore, it is preferable to use a concentration method according to the raw material used in the previous step, and the nonvolatile content is concentrated to 30% by mass or more, preferably 50% by mass or more.

  In general, metal nanoparticles in the size region of several tens of nm have characteristic optical absorption due to surface plasmon excitation, depending on the metal species. Therefore, by measuring the plasmon absorption of the obtained dispersion, it is possible to confirm that the metal is present as fine particles of nanometer order in the dispersion, and further, the dispersion is cast. It is also possible to observe the average particle diameter, distribution width, etc. in a TEM (transmission electron microscope) photograph of the film obtained in this manner.

  The concentrate obtained above can be used as a paste as it is. Furthermore, the desired dispersion medium (Z) is appropriately added to the concentrate once concentrated, and the mixture is stirred and mixed to form a paste. The concentrate is powdered by vacuum drying, freeze drying, or the like, and then the desired dispersion medium. Any of the methods of dispersing in (Z) and making a new “paste” may be used. In particular, when the substrate to be used is made of glass or metal, it is necessary to disperse the cumulus average particle diameter in a good state of 100 nm or less in order to ensure the adhesion of the fired metal film to the substrate.

  Depending on the intended use of the paste of the present invention, the dispersion medium (Z) can be selected from various hydrophilic solvents, hydrophobic solvents, or mixed solvents thereof. Among them, the dispersion medium (Z) is preferably a solvent composed of a compound having a hydroxy group from the viewpoint that uniform dispersibility can be easily obtained. Water alone or water and alcohol such as methanol, ethanol, isopropyl alcohol, etc. The mixed solvent is most preferable.

  Examples of the hydrophilic solvent include water, methanol, ethanol, isopropyl alcohol, tetrahydrofuran, acetone, dimethylacetamide, dimethylformamide, ethylene glycol, diethylene glycol, propylene glycol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol dimethyl ether, propylene. Glycol dimethyl ether, dimethyl sulfone oxide, dioxirane, N-methylpyrrolidone and the like can be mentioned, and these may be used alone or in admixture of two or more.

  Examples of the hydrophobic solvent include hexane, cyclohexane, ethyl acetate, butanol, methylene chloride, chloroform, chlorobenzene, nitrobenzene, methoxybenzene, toluene, xylene, and the like. good.

  Examples of other solvents that can be used by mixing with a hydrophilic solvent or a hydrophobic solvent include propyl acetate, butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, and the like. Depending on the intended use of the silver paste to be used, it may be appropriately selected and used.

  Further, the concentration of the metal nanoparticles (Y) in the paste is not particularly limited, but the metal-containing concentration in the paste is 10 to 70% by mass from the viewpoint of the conductivity of the conductive film or pattern. It is preferable that it is 20-60 mass% especially. The metal concentration in the paste can be adjusted according to the form of the application field in which the paste is used. Also, the viscosity of the paste is not particularly limited, but it is 1 to 15,000 mPa.s from the viewpoint of application to an ink jet apparatus capable of drawing a fine wiring. S is preferred. The viscosity of a paste can be adjusted according to the form of the application field which uses the paste.

  The paste used in the present invention is excellent in adhesion to various substrates by itself, but for further improvement of adhesion, dispersion stability of the paste, storage stability, film forming property, etc. In addition, a hydrophilic polymer may be added. The hydrophilic polymer is not particularly limited. For example, polyoxyethylene, polyoxypropylene, polyvinyl alcohol, partially saponified polyvinyl alcohol, polyethylene glycol, polyethyleneimine, polypropyleneimine, polyhydroxyethyl acrylate, polyhydroxyethyl methacrylate. , Dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, polyacetylethyleneimine, polyacetylpropyleneimine, polypropionylethyleneimine, polypropionylpropyleneimine, polyacrylamide, polyisopropylacrylamide, polyvinylpyrrolidone, polyacyloxazoline, polyethyloxazoline, poly Polymers such as propyloxazoline or the above polymers From the viewpoints of adhesion to various substrates such as glass, plastic and metal and dispersion stability of the metal paste, polyethylene glycol can be mentioned. , 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 to the paste is not particularly limited, and various conductive material components, components that improve the affinity and adhesion to electronic materials, etc., the surface is smooth or uneven Can be mentioned, components having various boiling points, solvents having various boiling points, viscosity modifiers, various polymers other than the hydrophilic polymer, ceramics, coupling agents, crosslinking agents, and the like.

  The paste used in the present invention is a dispersion containing the composite of the metal nanoparticles (Y) and the compound (X) obtained by the above-described method, and the various additives are added to a bead mill, a paint conditioner, an ultrasonic homogenizer, a filter. Dispersed by stirring method, ultrasonic method, mixer method, three-roll method, ball mill method, etc. using equipment such as mix, homogenizer, disper, three-one motor, especially for glass and metal substrates When coating, it is necessary to disperse the cumulant average particle size to 100 nm or less. In order to make a cumulant average particle diameter into a dispersion state of 100 nm or less, it is particularly preferable to combine a plurality of methods among these dispersion methods.

  Subsequently, the obtained paste is directly applied onto various substrates such as plastic, glass, and metal, but the application method is not particularly limited. For example, the application method includes a spin coater, bar coater, applicator, various printing machines, a method using a dispenser, a method by dipping into a paste, a method using a flow gun or a flow coater, a spraying method by spraying, etc. Examples thereof include brush coating, puff coating, roller coating, and the like. The shape formed by coating can be applied by selecting various thickness lines, fine patterns, patterns, etc. from various methods according to the purpose.

  The shape of the various substrates that can be used in the present invention is not particularly limited, and engraving is performed from a simple shape such as a three-dimensional molded product in addition to a film shape, a sheet shape, and a plate shape. It is possible to use those having complicated shapes and the like, and in particular, it can be suitably applied to a film or sheet-like flexible substrate. 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.

  Examples of the plastic substrate include polyethylene, polypropylene, polycarbonate, polyester, polystyrene, unsaturated polyester resin, vinyl chloride resin, epoxy resin, phenol resin, melamine resin, urea resin, AS resin, ABS resin, and 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. The base material which consists of these organic materials is 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. Therefore, since a hydrophilic solution composition is usually repelled with poor wettability to the hydrophobic substrate, it is difficult to produce a coating film with high adhesion. However, even if the paste used in the present invention uses a hydrophilic dispersion medium, the hydrophobic group is caused by the interaction with the hydrophobic substrate by the metal nanoparticles (Y) capped with the compound (X) as a protective agent. It can be applied to the material in a good state, and is excellent in film forming properties and printability.

  The paste used in the present invention expresses high adhesion to these plastic substrates even at low temperature firing of 150 ° C. or less, and therefore may be a flexible plastic substrate having a glass transition temperature of 180 ° C. or less. As temperature, it can set suitably according to the kind of base material and the level of the target physical property (conductivity etc.) in the range of 60-180 degreeC.

  Moreover, it is possible to form a highly adhesive coating on a glass substrate or a metal substrate by using a paste in which the cumulant average particle size is highly dispersed to 100 nm or less. The metal substrate is preferably made of a metal different from the metal species in the metal nanoparticles (Y), and examples thereof include a copper plate, an aluminum plate, and a nickel plate. The firing temperature after application to a glass substrate or metal substrate can be appropriately set in the range of 60 to 200 ° C. in view of the heat resistance of these substrates and according to the intended physical properties.

  In the present invention, by heating and baking various substrates such as plastic, glass, and metal after the paste application obtained above, a metal film is formed on these substrates. Is not particularly limited. For example, when the paste is coated, coated, or laminated by the above-described method on a base material, or the base material filled with the paste using a mold or a formwork is dried in an electric furnace, Examples thereof include a method of baking using various heating devices such as a machine, an oven, a thermostatic bath, and a hot stage, and a method of heating after natural drying at room temperature of 25 ° C to 30 ° C.

  Various metal film substrates obtained by the present invention are obtained by applying the above paste on the above-described plastic, glass, and metal substrate, and the paste layer or metal nanoparticles are formed on the substrate. An organic-inorganic composite layer fused or crystallized by heat treatment or baking treatment is laminated. In addition, the paste layer and the organic-inorganic composite layer are obtained by repeatedly applying the paste layer containing the same or different metal species and the organic-inorganic composite layer on the base material a plurality of times. A laminated board may be sufficient. At that time, the shape, area, thickness, conditions, method, and the like to be applied may be the same or different. Further, the same or different metal paste layer to be repeatedly applied, and a layer applied between the organic-inorganic composite layer and a material that does not contain metal nanoparticles and components that have been fused or crystallized by the above-described treatment. Is also possible.

  In the present invention, the firing and fusing processes in which a metal film showing high adhesion to plastics and various substrates of glass and metal are described. When the paste is formed on various substrates and then heated, the compound (X) capped on the metal nanoparticles (Y) is removed, and the metal nanoparticles (Y) are subsequently fused with each other, and crystal growth is favorable. A metal film is formed. At that time, the compound (X) in the paste remains uniformly on the surface of the metal coating and acts as a strong anchoring force between the various substrates, so that the adhesiveness to various substrates is good, In addition, it can be inferred that an added value such as suppressing the occurrence of cracks, cracks and the like in the coating can be expressed. That is, in the prior art, a compound that is a protective agent for metal fine particles had to be removed by volatilization / decomposition during film formation, but in the present invention, the compound (X) that functions as a protective agent is removed. It is not necessary, but rather, it is a major feature that it is made by presenting a function of imparting adhesion to various substrates and making the coating uniform by being present together with the metal coating. In particular, it is easy to form a metal film on glass, which has been considered to have poor adhesion to metals, and to form a film of dissimilar metals on a metal substrate simply by adjusting the dispersion state in the paste. What has become possible indicates that the usefulness of the present invention is high, and can be considered to be due to the function of the compound (X) which is the specific protective agent of the present invention.

  In addition to various chemical, electrical, magnetic, optical, colorant properties, etc. of the metal nanoparticles (Y), various metal film substrates obtained by the present invention are compounds that are organic components ( X) has properties such as moldability, film-forming property, adhesiveness and flexibility. The application is not limited, and can be used in a very wide range of fields such as catalysts, electronic materials, magnetic materials, optical materials, various sensors, color materials, medical examination applications, and the like. Since the ratio of silver contained in the coating or wiring can be easily adjusted, the effect according to the purpose can be efficiently expressed.

The flexible plastic substrate of the present invention is obtained by using a flexible plastic substrate in the above-described manufacturing method, and is characterized in that there is no change in conductivity even after repeating the 180 ° bending test 100 times. Is. Specifically, the following formula (1)
(Sheet resistance value after test−sheet resistance value before test) / sheet resistance value before test (1)
The change rate of the sheet resistance value calculated | required by is 10% or less, and is excellent in adhesiveness with a plastic base material. The rate of change can be 5% or less, further 1% or less, by selecting the type of flexible plastic substrate to be applied and the heating conditions after application, and is highly industrially useful.

  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
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
Dynamic scattering particle size measuring device: FPAR-1000, manufactured by Otsuka Electronics Co., Ltd.

Synthesis Example 1 Synthesis of Compound (x1) and Synthesis of Complex Using the Compound 1-1 [Tosylation Reaction of Polyethylene Glycol]
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)

1-2 [Synthesis of Compound (x1)]
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), then dried under reduced pressure, and a compound (x1) in which polyethylene glycol was bound to branched polyethyleneimine 24.4 g of a 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)

1-3 [Synthesis of complex with silver nanoparticles]
10.0 g of silver oxide was added to 138.8 g of an aqueous solution using 0.592 g of the compound (x1) obtained in 1-2, 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.

  A mixed solvent of 200 ml of isopropyl alcohol and 200 ml of hexane was added to the dispersion obtained after completion of the reaction and stirred for 2 minutes, followed by centrifugal concentration at 3000 rpm for 5 minutes. After removing the supernatant, a mixed solvent of 50 ml of isopropyl alcohol and 50 ml of hexane was added to the precipitate and stirred for 2 minutes, followed by centrifugal concentration at 3000 rpm for 5 minutes. After removing the supernatant, a small amount of water was added to the precipitate and stirred, and then the organic solvent was removed under reduced pressure to obtain an aqueous concentrate of the complex of silver nanoparticles (Y1) and compound (x1). It was.

  The obtained complex was sampled, and the peak of the plasmon absorption spectrum was observed at 400 nm by measuring the visible absorption spectrum of the diluted solution, and the production of silver nanoparticles was confirmed. Moreover, spherical silver nanoparticles (average particle diameter: 17.5 nm) were confirmed by TEM observation. As a result of measuring the silver content in the solid using TG-DTA, it was 97.2%.

  The above aqueous concentrate is left to stand in a -40 ° C. freezer for one day to freeze, and this is treated with a freeze dryer (FDU-2200, manufactured by Tokyo Rika Kikai Co., Ltd.) for 24 hours. A flaky mass was obtained. The obtained mass was the above analysis result similar to the aqueous concentrate.

Synthesis Example 2 Synthesis of Compound (x2) and Synthesis of Complex Using the Compound 2-1 [Synthesis of Monofunctional Epoxy Resin]
Bisphenol A type linear epoxy resin EPICLON AM-040-P (manufactured by DIC Corporation, epoxy equivalent 933) 18.7 g (20 m equivalent), 4-phenylphenol 1.28 g (7.5 mmol), 65% ethyltriphenyl acetate A phosphonium ethanol solution (0.26 ml, 0.12 mol%) and N, N-dimethylacetamide (50 ml) were mixed and 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%.

¹ H-NMR measurement was performed, and as a result of considering the integration ratio of the epoxy group, 0.95 epoxy rings remained in one molecule of the bisphenol A type linear epoxy resin, and it was confirmed that the epoxy resin was a monofunctional epoxy resin.

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)

2-2 [Synthesis of Compound (x2)]
A solution of the monofunctional epoxy resin obtained above (3.0 g, 1.5 mmol) and acetone (50 ml) in the compound (x1) 14.4 g (0.48 mmol) obtained in Synthesis Example 1-2, 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 (x2) formed by bonding polyethylene glycol and an epoxy resin to branched polyethyleneimine.

2-3 [Synthesis of complex with silver nanoparticles]
When 23.0 g of dimethylethanolamine was gradually added to 77.0 g of an aqueous solution using 0.263 g of the compound (x2) obtained in 2-2 above while stirring, a slight 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.

  A mixed solvent of 100 ml of isopropyl alcohol and 100 ml of hexane was added to the dispersion liquid after completion of the reaction obtained above and stirred for 2 minutes, followed by centrifugal concentration at 3000 rpm for 5 minutes. After removing the supernatant, a mixed solvent of 25 ml of isopropyl alcohol and 25 ml of hexane was added to the precipitate and stirred for 2 minutes, followed by centrifugal concentration at 3000 rpm for 5 minutes. After removing the supernatant, a small amount of water was added to the precipitate and stirred, and then the organic solvent was removed under reduced pressure to obtain an aqueous concentrate of a complex of silver nanoparticles (Y1) and compound (x2). .

  The obtained complex was sampled, and a peak of a plasmon absorption spectrum was observed near 400 nm by measuring a visible absorption spectrum of the diluted solution, and the production of silver nanoparticles was confirmed. Moreover, spherical silver nanoparticles (average particle diameter 18.8 nm) were confirmed by TEM measurement. Moreover, as a result of measuring the silver content in solid using TG-DTA, 96.6% was shown.

Synthesis Example 3 Synthesis of Complex with Gold Nanoparticles Using Compound (x1) 15.4 g of dimethylethanolamine was added to 97.2 g of an aqueous solution using 0.592 g of compound (x1) obtained in 1-2, and 25 Stir at 30 ° C. for 30 minutes. Subsequently, when 118.5 g of a 10% aqueous solution of tetrachloroauric acid tetrahydrate was gradually added with stirring, the reaction solution turned black-red and slightly exothermic. Thereafter, stirring was continued for 8 hours while maintaining 25 ° C. to obtain a black-red dispersion.

  A mixed solvent of 300 ml of isopropyl alcohol and 300 ml of hexane was added to the dispersion obtained after completion of the reaction and stirred for 2 minutes, followed by centrifugal concentration at 3000 rpm for 5 minutes. After removing the supernatant, a mixed solvent of 100 ml of isopropyl alcohol and 100 ml of hexane was added to the precipitate and stirred for 2 minutes, followed by centrifugal concentration at 3000 rpm for 5 minutes. After removing the supernatant, a small amount of water was added to the precipitate and stirred, and then the organic solvent was removed under reduced pressure to obtain an aqueous concentrate of the complex of gold nanoparticles (Y2) and compound (x1). It was.

  The obtained complex was sampled, and the peak of the plasmon absorption spectrum was observed at 550 nm by the visible absorption spectrum measurement of the diluted solution, confirming the formation of gold nanoparticles. In addition, spherical gold nanoparticles (average particle diameter 10.5 nm) were confirmed by TEM observation. As a result of measuring the gold content in the solid using TG-DTA, it was 95.2%.

Example 1 [Production of silver and gold paste]
In accordance with the composition shown in Tables 1 to 10, water or ethanol was added to the aqueous concentrate or bulky composite obtained in Synthesis Example 1 and the aqueous concentrate of the composite obtained in Synthesis Example 2 or 3. If necessary, a compound in which polyethylene glycol is bonded to the branched polyethyleneimine obtained in Synthesis Example 1-2 is added as a dispersion stabilizer to 1 wt% of the entire paste, and uniformly dispersed to obtain a solid content ratio. 30% silver or gold pastes AD were obtained. A homodisper (manufactured by PRIMIX Co., Ltd.) was used for mixing and dispersing.

[Production of plastic substrate]
After fixing the plastic film shown in Table 1 having the same size on a 15 cm square glass substrate with a double-sided tape, it was set on a spin coater (1H-DX2 type, manufactured by Mikasa Corporation). A silver paste was placed on the plastic film and spin coated at 700 rpm for 20 seconds. Similarly, a silver paste was placed on a plastic film and applied with a bar coater (RDS08).

  The substrate coated with a spin coater or a bar coater was heated at 120 ° C., 150 ° C., and 180 ° C. for 30 minutes to produce a plastic substrate. The obtained plastic substrate is evaluated as follows, and the results are shown in Tables 1 to 10.

[Evaluation of dispersibility, printability and adhesion]
The dispersibility was evaluated as good (◯), normal (Δ), and poor (×) by judging the brightness of the mirror surface of the coating film obtained by applying the paste on the plastic film.

  As for the printability, the coating film coated with the above paste was evaluated as good (◯) when the plastic film was coated with no spots, and the state with spots due to flipping was evaluated as poor (×). .

  Adhesion was determined by a cross-cut test (JIS K5400) and a 180 ° bend test (JIS K5400) on a plastic substrate obtained by firing. The 180 ° bend test was performed by repeating the 180 ° bend test 100 times using a coating film obtained by applying a paste on a plastic film. A crack was evaluated as a defect (x). Furthermore, the conductivity measurement before and after the bending test was performed simultaneously.

Footnotes in Tables 1 to 10 A: Silver paste prepared from the aqueous concentrate of the composite obtained in Synthesis Example 1 B: Silver paste prepared from the mass of the composite obtained in Synthesis Example 1 C: Obtained in Synthesis Example 2 Silver paste prepared from composite aqueous concentrate D: Gold paste prepared from composite aqueous concentrate obtained in Synthesis Example 3 PET: Film made of polyethylene terephthalate (Toyobo Ester Film, Toyobo Co., Ltd.)
PI: Polyimide film (Kapton Film, Toray DuPont Co., Ltd.)
PEN: Polyethylene naphthalate film (Teonex, Teijin DuPont Films Ltd.)
Conductivity (Ω / □): sheet resistance (Mitsubishi Chemical Corporation, low resistivity meter Loresta EP)

  As can be seen from Tables 1 to 10, the plastic film obtained according to the present invention does not require a primer layer on the film or special processing or treatment to serve as a primer layer, and has a low firing temperature. Also showed high adhesion to the film substrate.

Comparative Example The above test was carried out in the same manner using a nano silver paste (alcohol dispersion) manufactured by Nippon Paint Co., Ltd., but it failed the cross-cut test at 180 ° C. or lower (test result 0/100 ).

Examples 2-1 to 4 [Preparation of paste with controlled cumulant average particle size]
2-1
After replacing the aqueous concentrate obtained in Synthesis Example 1 with ethanol, the ethanol solvent was adjusted to a solid content of 40% and dispersed with an ultrasonic homogenizer. Cumulus average particle size was calculated from a dynamic scattering particle size measuring device at regular intervals, and the dispersion state was traced. Dispersion was terminated when it reached 56 nm. This is referred to as silver paste E.

2-2
After adding water to the flaky lump obtained in Synthesis Example 1 to adjust the solid content to 50%, the dispersion state was traced in the same manner as in Example 2-1. Dispersion was terminated when the average particle size reached 49 nm. This is referred to as silver paste F.

2-3
Water was added to the aqueous concentrate obtained in Synthesis Example 2 to adjust the solid content to 45%, and the dispersion state was traced in the same manner as in Example 2-1. Dispersion was terminated when the average particle size reached 65 nm. This is silver paste G.

2-4
After adding water to the aqueous concentrate obtained in Synthesis Example 3 to adjust the solid content to 60%, the dispersion state was traced in the same manner as in Example 2-1. Dispersion was terminated when the average particle size reached 45 nm. This is gold paste H.

[Production of glass and copper substrate]
A commercially available glass of 15 cm square and the one obtained by washing and drying the upper surface of the copper substrate with acetone and ethanol were used as they were. The pastes E to H obtained by controlling the dispersion state as described above were placed and applied with a bar coater (RDS08).

  The substrate coated with a bar coater was heated at 120 ° C., 150 ° C., and 180 ° C. for 30 minutes to produce a glass or copper substrate. The obtained glass or copper substrate is evaluated as follows, and the results are shown in Tables 11-12.

[Evaluation of dispersibility, printability and adhesion]
The dispersibility was evaluated as good (◯), normal (Δ), and poor (×) by visually judging the brightness of the coating film on the glass or copper substrate.

  The printability was evaluated as good (◯) when the above-mentioned coating film was coated with no spots, and poor (×) when spotted due to playing.

  The adhesion was determined by a filling test using an adhesive tape with respect to the coating film on the glass substrate obtained by firing, and by a cross-cut test (JIS K5400) for the coating film on the copper substrate. Furthermore, the adhesiveness with respect to a board | substrate was judged more severely by the rubbing test using a cotton swab with respect to the coating film on a copper substrate.

  In the filling test, the adhesive tape (manufactured by Nichiban Co., Ltd.) was strongly pressed with the thumb to the area of 1 cm in the vertical direction and 2 cm in the width of the coating film on the glass substrate. The case where the gold coating film was not peeled off at all was evaluated as good (O), and the case where the gold coating film was peeled off was evaluated as defective (X). The rubbing test is that the film on the copper substrate is rubbed 100 times with a cotton swab and then the silver or gold film on the substrate is not peeled off (good), and the lower substrate comes out Was evaluated as defective (x).

  As can be seen from Tables 11 to 12, by using a paste whose dispersion state is controlled in the present invention, a primer layer is provided on a glass or metal substrate, or special processing or processing that serves as a primer layer is performed. It can be seen that it is not necessary to add the third component compound to increase the adhesion, and that the high adhesion to the substrate is exhibited even at a low firing temperature.

  The plastic, glass, or metal substrate obtained by the present invention is formed by directly laminating a metal film and conductive wiring on the base material, and exhibits high adhesion. Therefore, it is suitably used as various conductive materials. be able to.

Claims (1)

(I ″) a compound (x1) formed by binding polyethylene glycol (b) having a number average molecular weight of 500 to 5,000 to an amino group in polyethyleneimine (a) having a number average molecular weight of 500 to 50,000, Alternatively, the polyethylene glycol (b) having a number average molecular weight of 500 to 5,000 and the linear epoxy resin (c) are bonded to the amino group in the polyethyleneimine (a) having a number average molecular weight of 500 to 50,000. Compound (x2)
A step of directly applying a paste containing the compound (X), the metal nanoparticles (Y), and the dispersion medium (Z) on a flexible plastic substrate,
(II ″) a step of heating the flexible plastic substrate after applying the paste obtained in the step (I ″) at 60 ° C. to 150 ° C.,
The sheet resistance value of the flexible plastic substrate obtained by the following formula (1) after 100 times of 180 ° bending test:
(Sheet resistance value after test−sheet resistance value before test) / sheet resistance value before test (1)
A flexible plastic substrate characterized in that the rate of change represented by is 10% or less.