JP2018154073A - Silver nanoparticle laminate and method for producing silver nanoparticle laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silver nanoparticle laminate having enhanced scratch resistance, and to provide a method for producing the silver nanoparticle laminate.SOLUTION: A silver nanoparticle laminate 10 includes: a base material 1; a silver nanoparticle resin layer 2 which is formed on the base material 1 and contains silver nanoparticles; and an overcoat layer 3 which is formed on the silver nanoparticle resin layer 2 and contains a three-dimensional crosslinked structure obtained by irradiation with ionization radiation. The silver nanoparticles are coated with protective molecules, and the protective molecules contains alkyldiamine having a primary amino group and a tertiary amino group as a main component. A resin layer containing the silver nanoparticles contains a copolymer of (meth)acrylate which has a carboxyl group on a side chain and is soluble in a solvent.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a silver nanoparticle laminate and a method for producing a silver nanoparticle laminate.

  Silver nanoparticles have electrical, thermal and optical properties not found in other materials, and are used in a wide range of products from solar cells to sensors. Furthermore, unlike many other dyes and pigments, silver nanoparticles are extremely effective in absorbing and scattering light, and have a color depending on the size and shape of the particles. The strong relationship between light and silver nanoparticles is called surface plasmon resonance, because conduction electrons on the metal surface cause collective oscillation when excited by light of a specific wavelength. Causes absorption characteristics.

  In general, a coating liquid in which metallic silver is dispersed is often used for metallic wiring. For example, a pattern is formed on a wiring board with a coating liquid in which metallic silver is dispersed, and wiring is formed by sintering metallic silver contained in the coating liquid. In the case of using metallic silver as a conductive material, it is known that it is necessary to sinter at a low temperature by utilizing a melting point drop due to refinement of dispersed metallic silver. At present, miniaturized nano-sized metal nanoparticles are expected as materials that can be sintered at low temperature.

However, fine metal silver particles exhibiting a melting point drop tend to contact each other and aggregate. In order to prevent this agglomeration, it is necessary to add a dispersant to the coating liquid described above. However, by adding the dispersant, the surface plasmon resonance unique to the metal nanoparticles is inhibited, and the specific color development is adversely affected. There is a possibility of effect.
Moreover, in order to produce a functional film having optical characteristics peculiar to silver nanoparticles, it is necessary to form a silver film that has a good dispersibility and does not sinter at low temperatures. Further, when it is desired to produce a coating film having a metallic luster, it is necessary to produce the metallic luster at a relatively low temperature after coating, and the sintering temperature must be able to be changed depending on the application. Furthermore, it is necessary to have a coating liquid composition that does not aggregate even if a resin component for increasing film strength and adhesion to the substrate is added in addition to the silver nanoparticles and the dispersant.

Conventionally, when trying to obtain silver nanoparticles, generally, an aqueous solution in which a silver salt such as silver nitrate or silver chloride is dissolved is used to reduce the existing silver ions with any reducing agent to form a metal salt in a desired form. It was normal to make it precipitate as (patent document 1-patent document 3).
In particular, in the production of fine silver particles, a method of aggregating atomic silver in a vacuum to form silver nanoparticles is also known (Patent Document 4).

Moreover, the method etc. which manufacture a silver nanoparticle via a silver oxalate amine complex by mixing silver oxalate and an amine and thermally decomposing are also known (patent documents 5 and patent documents 6).
According to this technique, silver atoms generated by dissociation from a compound as a raw material do not pass through a silver ion state in the process of forming silver nanoparticles.
For this reason, if it is the said method, it is not necessary to mix the reducing agent for reduce | restoring silver ion, and it is possible to manufacture silver fine particles with a uniform average particle diameter with a simple method. Furthermore, when the amine complex is decomposed, the amino group of the amine molecule is coordinated on the surface of the silver particle, so that silver nanoparticles that can be dispersed in a certain organic solvent can be obtained without adding a dispersant.

Special table 2012-509396 gazette JP 2012-180589 A JP 2012-140701 A JP 2002-121437 A JP 2012-162767 A Japanese Patent No. 5574761

  However, when a silver nanoparticle film is formed by applying only this silver nanoparticle dispersion, the silver nanoparticle film peels off from the substrate because the strength of the silver nanoparticle film and the adhesion to the substrate are not sufficient. There is a problem that it is easy to wear, that is, scratch resistance is low.

  This invention is made | formed in view of said situation, and it aims at providing the manufacturing method of the silver nanoparticle laminated body which improved abrasion resistance, and a silver nanoparticle laminated body.

  In order to solve the above problems, a silver nanoparticle laminate according to one embodiment of the present invention includes a base material, a resin layer formed on the base material and containing silver nanoparticles, and the silver nanoparticles. And an overcoat layer including a three-dimensional crosslinked structure formed on the resin layer and obtained by irradiation with ionizing radiation.

  Further, according to one embodiment of the present invention, the silver nanoparticles may be covered with a protective molecule, and the protective molecule may contain an alkyl diamine having a primary amino group and a tertiary amino group as a main component. Good.

  Furthermore, according to one aspect of the present invention, the resin layer containing silver nanoparticles may contain a solvent-soluble (meth) acrylic acid ester copolymer having a carboxy group in the side chain as a main component. .

  According to an aspect of the present invention, the overcoat layer may include a resin having a three-dimensional crosslinked structure having a urethane bond.

  According to an aspect of the present invention, the average particle diameter of the silver nanoparticles is preferably 30 nm or less.

  The method for producing a silver nanoparticle laminate according to one embodiment of the present invention includes a silver nanoparticle, a dispersion solvent, and a solvent-soluble (meth) acrylic acid ester copolymer having a carboxy group in a side chain as a main component. And a step of forming a silver nanoparticle resin layer by applying a composition for a silver nanoparticle resin layer on the substrate and drying the composition, and a compound having at least two polymerizable unsaturated double bonds in the molecule An overcoat layer composition containing a photopolymerization initiator and a solvent is applied onto the silver nanoparticle resin layer and dried, and then the overcoat layer composition is cured to form an overcoat layer. Forming.

  Moreover, the manufacturing method of the silver nanoparticle laminated body which concerns on another one aspect | mode of this invention is a solvent-soluble (meth) acryl which has a carboxy group in a silver nanoparticle, a dispersion | distribution solvent, and a side chain on a base material. A layer comprising a composition for a silver nanoparticle resin layer containing an acid ester copolymer, a compound having at least two polymerizable unsaturated double bonds in the molecule, a photopolymerization initiator, and a solvent. The step of simultaneously forming the layer made of the composition for overcoat layer in this order, the layer made of the composition for silver nanoparticle resin layer, and the layer made of the composition for overcoat layer are simultaneously dried. And a step of curing the dried layer made of the composition for an overcoat layer to form an overcoat layer.

  According to one embodiment of the present invention, a silver nanoparticle laminate having improved scratch resistance by laminating an overcoat layer having good film strength and good adhesion with a silver nanoparticle resin layer on the silver nanoparticle resin layer. It becomes possible to provide the manufacturing method of a body and a silver nanoparticle laminated body.

It is sectional drawing which shows typically the structure of the silver nanoparticle laminated body which concerns on embodiment of this invention. It is a figure which shows the scanning electron microscope image of the silver nanoparticle observed after apply | coating the toluene solvent dispersion liquid of the silver nanoparticle obtained in Example 1 of this invention to the board | substrate and making it dry. It is a figure which shows the particle size distribution and cumulative frequency (%) of the silver nanoparticle obtained in Example 1 of this invention.

  Below, with reference to drawings, the manufacturing method of the silver nanoparticle laminated film which concerns on embodiment of this invention, a silver nanoparticle laminated body, and a silver nanoparticle laminated film is demonstrated. Here, the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Further, the embodiment described below exemplifies a configuration for embodying the technical idea of the present invention, and the technical idea of the present invention is that the material, shape, structure, etc. of the component parts are as follows. It is not something specific. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

(Configuration of silver nanoparticle laminate 6)
FIG. 1 is a cross-sectional view schematically showing a configuration of a silver nanoparticle laminate 6 according to an embodiment of the present invention.
A silver nanoparticle laminate 6 shown in FIG. 1 is formed on a base 1, a silver nanoparticle resin layer 2 containing silver nanoparticles 4, and a silver nanoparticle resin layer 2 formed on the base 1. And at least an overcoat layer 3. The silver nanoparticle resin layer 2 and the overcoat layer 3 are collectively referred to as a silver nanoparticle multilayer film 5. Hereinafter, the details of each layer described above will be described.

[Substrate 1]
The substrate 1 is a member that supports the silver nanoparticle resin layer 2. For this reason, if it can support and form the silver nanoparticle resin layer 2, the kind of base material will not be ask | required. In this embodiment, as the base material 1, for example, a PET (polyethylene terephthalate) film can be used.

[Silver nanoparticle resin layer 2]
The silver nanoparticle resin layer 2 includes a copolymer of silver nanoparticles 4 and a solvent-soluble (meth) acrylic acid ester having a carboxy group in the side chain, which is formed on the base material 1. A layer is preferred. The surface of the silver nanoparticles 4 contained in the silver nanoparticle resin layer 2 is preferably covered with a protective molecule containing, for example, an alkyldiamine having a primary amino group and a tertiary amino group as a main component. Moreover, it is preferable that the above-mentioned silver nanoparticle is dispersible in the organic solvent, and the average particle diameter is 30 nm or less, for example.

[Overcoat layer 3]
The overcoat layer 3 is a layer that is formed on the silver nanoparticle resin layer 2 and includes a three-dimensional crosslinked structure obtained by irradiation with ionizing radiation. More specifically, the overcoat layer 3 is a resin having a three-dimensional crosslinked structure obtained by polymerizing a compound having at least two polymerizable unsaturated double bonds in the molecule (hereinafter also simply referred to as “polymerizable compound”). In particular, a layer containing a resin having a three-dimensional crosslinked structure having a urethane bond is preferable. The overcoat layer 3 is
For example, a photopolymerization initiator may be included.
Moreover, it is preferable that the above-mentioned polymerizable compound is a compound containing, for example, at least one of a urethane (meth) acrylate monomer and an oligomer as a main component. In addition, the specific example of the polymeric compound which can be used by this embodiment is mentioned later.
The above-mentioned photopolymerization initiator is an initiator for photopolymerizing the above polymerizable compound. For this reason, the kind is not ask | required if the said compound can be photopolymerized. In addition, the specific example of the photoinitiator which can be used by this embodiment is mentioned later.

(Method for producing silver nanoparticle laminate 6)
[Synthesis of silver nanoparticles]
As a silver raw material constituting the silver nanoparticles, among silver-containing compounds, a silver compound that is easily decomposed by heating to form metallic silver is preferably used. As such a silver compound, for example, silver chloride, silver nitrate, silver carbonate or the like is used in addition to silver carboxylate in which carboxylic acid such as formic acid, acetic acid, oxalic acid, malonic acid, benzoic acid, phthalic acid and silver are combined. be able to.
Among these silver compounds, silver oxalate is preferably used from the viewpoint of easily generating a metal by decomposition and hardly generating impurities other than silver. Silver oxalate has a high silver content, and oxalate ions are decomposed and removed as carbon dioxide by heating. For this reason, it can be said that it is advantageous in that metal silver is obtained as it is by pyrolysis without requiring a reducing agent, and impurities hardly remain.

In this embodiment, a predetermined alkyl diamine is added to the silver compound to form a complex compound of the silver compound and the amine. This complex compound includes silver, alkyldiamine and oxalate ion. In this complex compound, it is presumed that the nitrogen atom contained in the amine is coordinated through the lone pair to each silver atom contained in the silver compound, thereby forming a complex compound. The In this case, the amino group is preferably primary RNH2 (R is a hydrocarbon group), and when it is a tertiary amino group, it is difficult to spatially coordinate with the silver atom. For this reason, if the alkyldiamine is a primary or tertiary amino group, the primary amino group is selectively coordinated to a silver atom, and the tertiary amino group faces outward depending on the molecular chain.
Although the secondary amino group can be coordinated, it is preferable to use a primary amino group and a tertiary amino group because it is expensive due to a synthesis problem and the reactivity is lower than the primary.

The metallic silver atoms coordinated by the diamine thus produced quickly aggregate after the production, and form metallic bonds with each other to form silver nanoparticles. At this time, since the diamine coordinated to each silver atom forms a protective film on the surface of the silver nanoparticle, after a certain silver atom gathers to form the silver nanoparticle, the protective film of the diamine prevents it. It is considered difficult to bond the above silver atoms.
For this reason, even when the decomposition of the silver compound contained in the complex compound and the generation of the silver nanoparticles are carried out in the state where the solvent is not present and silver atoms are present at a very high density, the particle size is typically 30 nm. It is considered that silver nanoparticles having a uniform particle size can be obtained stably below.

In the formation of the complex compound of the silver compound and the diamine, the molar ratio of the silver atom to the diamine is preferably 1: 1 to 1: 4, and more preferably 1: 2 to 1: 4. When the amount of diamine is reduced beyond the above range in the formation of a complex compound of a silver compound and a diamine, the proportion of silver atoms not coordinated with the diamine increases, and the resulting silver nanoparticles become enlarged. .
In addition, since silver nanoparticles having an average particle diameter of approximately 30 nm or less can be stably obtained by the presence of a diamine that is twice or more the amount of silver atoms, it is ensured that this amount of diamine ensures It is considered that the silver atom can be coordinated by diamine.
Moreover, since the density of silver atoms in the reaction system decreases when the amount of diamine exceeds 4 times the amount of silver atoms, the final yield of silver recovery decreases, so the amount of diamine used is 4 times the amount of silver atoms. The following is preferable.
Further, when the molar ratio of silver atom to diamine is about 1: 1, there is no dispersion solvent in which all amines coordinate with silver atoms to form a complex compound and hold the reaction system. Therefore, it is also preferable to mix a reaction solvent such as methanol as necessary.

When a complex compound of a silver compound and a diamine is heated with stirring, a suspension exhibiting a blue gloss is obtained. By removing excess diamine and the like from this suspension, silver nanoparticles whose surface is coated with the protective molecules according to the present embodiment (hereinafter, also simply referred to as “coated silver nanoparticles”) can be obtained.
The conditions for heating the complex compound of silver compound and diamine to obtain coated silver nanoparticles depend on the conditions such as temperature, pressure, and atmosphere when performing thermal decomposition according to the type of silver compound and diamine used. It can be selected as appropriate. At this time, from the viewpoint of preventing the generated coated silver nanoparticles from being contaminated by the reaction with the atmosphere in which pyrolysis is performed or the protective film covering the surface of the silver nanoparticles from being decomposed, an argon atmosphere or the like is used. It is preferable to thermally decompose the silver compound in an inert atmosphere.
On the other hand, when silver oxalate is used as the silver compound, the reaction space is protected by carbon dioxide generated by the decomposition of oxalate ions, so that the complex compound of silver oxalate and diamine can be heated in the atmosphere. Thermal decomposition of silver oxalate is possible.

  The temperature at which the complex compound of the silver compound and the diamine is heated for the thermal decomposition of the silver compound is preferably below the boiling point of the diamine generally used from the viewpoint of preventing the diamine from being eliminated. In the present embodiment, coated silver nanoparticles having a protective film formed of diamine can be obtained by heating to about 80 to 130 ° C. in general.

  As described above, in general, in this embodiment, the total amount of silver atoms: diamine is 1: 1 (molar ratio) compared to the synthesis method of other coated silver nanoparticles that require an excessive amount of alkylamine with respect to silver. However, since the coated silver nanoparticles can be synthesized in a high yield, the amount of alkyldiamine used can be reduced. In addition, carbon dioxide generated by thermal decomposition of oxalate ions is easily removed outside the reaction system, so there are no by-products derived from the reducing agent, and the coated silver nanoparticles can be easily separated from the reaction system. The purity of the coated silver nanoparticles is also high.

  Silver nanoparticles are expected as a clear yellow colorant. However, since the maximum absorption wavelength of the surface plasmon band appears on the longer wavelength side than 400 nm, there is a problem as a clear yellow colorant. In contrast, in the thermal decomposition of the oxalate ion / alkyldiamine / silver complex compound of the present embodiment, it is easy to obtain coated silver nanoparticles having a maximum absorption wavelength of the surface plasmon band on the shorter wavelength side than 400 nm. It is also useful as a coloring material for decorative items.

  The fact that the coated silver nanoparticles according to this embodiment have a maximum absorption wavelength of the surface plasmon band on the shorter wavelength side than 400 nm means that the silver atoms constituting the silver nanoparticles are made of an electrically neutral metal salt. This shows that the diamine constituting the coating is bonded to metallic silver by a coordination bond.

When the coated silver nanoparticles according to the present embodiment are dispersed in a solvent or the like used as a dispersion solvent, the excessive amount used in forming the protective film under the condition that the protective film of the silver nanoparticles is not detached. It is preferable to obtain a dispersion liquid in which the coated silver nanoparticles are dispersed by removing the alkyldiamine and the like and replacing it with a solvent to be used.
In particular, when the coated silver nanoparticles according to the present embodiment are exposed to the atmosphere or the like, the protective film is detached even at a low temperature, and aggregation sintering of the silver nanoparticles is started. For this reason, when replacing the coated silver nanoparticles with an appropriate solvent from alkyl diamine or the like, it is preferable to perform the replacement by selecting conditions under which the coated silver nanoparticles are not exposed to the atmosphere or the like.

In addition, using a dispersion liquid in which the coated silver nanoparticles according to the present embodiment are dispersed in an appropriate volatile dispersion solvent, the coating is formed on the desired substrate 1 by a spin coating method or an ink jet method. Thus, when applied as a color material or an optical functional film, the film strength and the adhesion to the base material 1 are weak only with a component consisting of silver, and it can be removed only by touching.
Therefore, it is necessary to add a component that increases the strength of the silver nanoparticle resin layer 2 and the adhesion between the silver nanoparticle resin layer 2 and the substrate 1. There are several methods for improving the film properties, but it is convenient to use a polymer. For this reason, the method of adding a polymer in which silver nanoparticles are easily dispersed to the coating solution is preferable. The polymer in which such silver nanoparticles are dispersed will be described later.
However, the above-mentioned polymer has low scratch resistance, is easily soluble in organic solvents and alkaline compounds, and has poor chemical resistance. Therefore, the overcoat layer 3 described later is separated on the silver nanoparticle resin layer 2 by separating the functions. It is essential to provide

Hereinafter, this embodiment will be described in more detail.
[Silver oxalate]
Silver oxalate has a high silver content and is usually thermally decomposed at 200 ° C. When pyrolyzed, the oxalate ions are removed as carbon dioxide, and the metal salt is obtained as it is.
For this reason, it is advantageous in that no reducing agent is required and impurities hardly remain. For these reasons, silver oxalate is preferably used as a silver compound that is a raw material of silver for obtaining coated silver nanoparticles in the present embodiment.
Hereinafter, the case where silver oxalate is used as the silver compound will be described. However, as described above, in the complex compound generated between the silver compound and the predetermined diamine, it goes without saying that the diamine is used without being limited to silver oxalate as long as the diamine is coordinated to the silver atom. .

  There is no restriction | limiting as silver oxalate used by this embodiment, For example, commercially available silver oxalate can be used. Further, 20 mol% or less of silver oxalate oxalate ions may be substituted with at least one of carbonate ions, nitrate ions and oxide ions, for example. In particular, when 20 mol% or less of oxalate ions are substituted with carbonate ions, there is an effect of increasing the thermal stability of silver oxalate. If the amount of substitution exceeds 20 mol%, the complex compound may be difficult to thermally decompose. In particular, in the case of an oxalate ion / alkyldiamine / silver complex compound containing an alkyldiamine having a boiling point of 250 ° C. or less, coated silver nanoparticles can be obtained with high efficiency by thermal decomposition at a low temperature of 100 ° C. or less.

[Alkyldiamine]
The structure of the alkyldiamine used in this embodiment is not particularly limited. Alkyl diamine reacts with silver oxalate to form the complex compound described above, so at least one amino group must be a primary amino group or a secondary amino group. Preferably there is. Furthermore, in order to increase the affinity with a nonpolar dispersion solvent, the other amino group is desirably a tertiary amino group.
Examples of the alkyl diamine include N, N-dimethylethylenediamine, N, N-diethylethylenediamine, N, N-dimethyl-1,3-propanediamine, N, N-diethyl-1,3-propanediamine, and N, N. -Dimethyl-1,5-diamino-2-methylpentane, N, N-dimethyl-1,6-hexanediamine and the like are exemplified, but not limited thereto. A plurality of different alkyl diamines may be simultaneously reacted with silver oxalate.

[Silver nanoparticle dispersed polymer]
The structure of the silver nanoparticle-dispersed polymer used in this embodiment is not particularly limited.
The silver nanoparticle-dispersed polymer contains a solvent-soluble (meth) acrylic acid ester copolymer as a main component and must have at least one carboxy group in the side chain. In addition to the carboxy group directly bonded, succinic acid, phthalic acid, hexahydrophthalic acid and the like may be included in the side chain. In addition to the monomer, styrene, α-methylstyrene, or the like may be included as a monomer component.
Specifically, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, benzyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, ( In addition to glycidyl (meth) acrylate and dicyclopentanyl (meth) acrylate, 2-hydroxyethyl meta (meth) acrylate reacted with dicarboxylic acid such as oxalic acid and phthalic acid, (meth) acrylic acid 2 -What reacted glycidyl (meth) acrylate and (meth) acrylic acid 2-isocyanatoethyl with hydroxyethyl may be used.
These monomers are used after being polymerized in a reaction solvent in the presence of a thermal polymerization initiator such as azobisisobutyronitrile. Commercial products such as Hyper MA4620 (acid value: about 130) manufactured by Negami Kogyo may also be used. In the present embodiment, “(meth) acrylic monomer” indicates both “acrylic monomer” and “methacrylic monomer”.

[Preparation of composition for overcoat layer]
In this embodiment, the composition for overcoat layers contains the compound (polymerizable compound) which has at least 2 or more polymerizable unsaturated double bond in a molecule | numerator.
As the compound, for example, a compound in which the hydroxyl group of a polyhydric alcohol having two or more alcoholic hydroxyl groups in one molecule is an esterified product of two or more (meth) acrylic acids is preferable.
Other examples include polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, and polyether (meth) acrylate, as well as those in which a reactive acryloyl group is bonded to an acrylic resin skeleton. It can be used as a compound of Moreover, what made the acryloyl group couple | bond with rigid skeletons, such as a melamine and isocyanuric acid, can also be used. Among these compounds, in this embodiment, when at least one of a urethane (meth) acrylate monomer and an oligomer is used, the hardness and flexibility of the overcoat layer 3 can be remarkably improved.

  The urethane (meth) acrylate having at least two polymerizable unsaturated double bonds in the molecule, which is preferable in this embodiment, is generally a product obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer. And (meth) acrylic monomers having a hydroxyl group can be reacted with each other.

Specific examples include pentaerythritol triacrylate hexadiamine isocyanate urethane prepolymer, dipentaerythritol pentaacrylate hexadiamine isocyanate urethane prepolymer, pentaerythritol triacrylate toluenediamine isocyanate urethane prepolymer, dipentaerythritol pentaacrylate toluene diisocyanate urethane prepolymer. A polymer, pentaerythritol triacrylate isophorone diisocyanate urethane prepolymer, dipentaerythritol pentaacrylate isophorone diisocyanate urethane prepolymer, and the like can be used.
Moreover, these monomers can be used 1 type or in mixture of 2 or more types. These may be monomers or oligomers that are partially polymerized. These resins are cross-linked by, for example, irradiating and applying energy by ionizing radiation such as heat or ultraviolet rays and electron beams. These compounds are appropriately selected in consideration of film strength, adhesion to a substrate, and curl amount.

  Commercially available urethane (meth) acrylates include Nagase Chemtech; (trade name “Denacol” series, etc.), Shin-Nakamura Chemical Co., Ltd. (trade name “NK Ester” series, etc.), DIC (trade name “UNDIC”). ("Series etc."), Nippon Oil & Fats Corporation (trade name "Blemmer" series etc.), Nippon Kayaku Co., Ltd. (trade name "KAYARAD" series etc.), Kyoeisha Chemical Co., Ltd. "Series etc.", Daicel Ornex Co., Ltd. (trade name "Ebecryl" series, etc.), Negami Kogyo Co., Ltd. (trade name "Art Resin" series, etc.), Nippon Synthetic Chemical Industry Co., Ltd .; Etc.) can be used.

  Specifically, Shin-Nakamura Chemical U-4HA, U-6HA, UA-100A, U-6LPA, U-15HA, UA-32P, UA-33H, UA-53H, U-324A, etc., Kyoeisha Chemical Co., Ltd. UA-306H, UA-306T, UA-306I, etc., UV-1700B, UV-6300B, UV-7600B, UV-7605B, UV-7640B, UV-7650B, etc., manufactured by Nippon Synthetic Chemical Industry Co., Ltd. Examples include, but are not limited to, Ebecryl-1290, Ebecryl-1290K, Ebecryl-5129 and the like, UN-3220H, UN-3220HB, UN-3220HS and the like of Negami Kogyo.

  The use ratio (content ratio) of the polymerizable compound constituting the overcoat layer composition of the present embodiment is preferably in the range of 50% to 95% in the composition, and if necessary, (meta) You may dilute with an acrylate monomer or a solvent.

Examples of the photo radical polymerization initiator constituting the overcoat layer composition of the present embodiment include acetophenones, benzophenones, α-hydroxyketone, benzylmethyl ketal, α-aminoketone, monoacylphosphine oxide, bisacyl. Phosphine oxide or the like is used alone or in combination. Specifically, Irgacure 184, Irgacure 651, Irgacure 1173, Irgacure 907, Irgacure 369, Irgacure 819, Irgacure from BASF
Examples include, but are not limited to, TPO, Escalure KIP-150 of Lambarti and Esacure ONE.

[Manufacturing process of silver nanoparticle laminate 6]
The 1st-5th process for manufacturing the silver nanoparticle laminated body 6 is demonstrated below.
In the first step, the coated silver nanoparticles described above are dispersed in a solvent or the like, and a solvent-soluble (meth) attacrylic acid ester homopolymer or copolymer is added to prepare a coating solution with adjusted concentration and viscosity. It is a process.
In the second step, the coating liquid prepared in the first step is applied to a film substrate or a glass substrate, and a layer made of a resin for a silver nanoparticle resin layer containing coated silver nanoparticles and a dispersion solvent is formed. It is a process of forming.
The third step is a step of forming the silver nanoparticle resin layer 2 by drying the layer.
In the fourth step, the above-mentioned composition for overcoat layer is dissolved in a solvent or the like to adjust the viscosity, and applied onto the silver nanoparticle resin layer 2 formed in the third step and dried. This is a step of forming a layer comprising the composition for an overcoat layer.
The fifth step is a step of forming the overcoat layer 3 by curing the layer by ionizing radiation irradiation treatment such as ultraviolet rays and electron beams.
The silver nanoparticle laminated body 6 which concerns on this embodiment is obtained through the said 1st-5th process.

Examples of the solvent of the coated silver nanoparticle dispersion used in the first step include toluene, cyclohexanone, butyl acetate, terpineol C, dihydroterpineol, and tersolve THA-90 manufactured by Nippon Terpene Chemical Co., Ltd. Moreover, you may mix and use several types among these solvents. The aforementioned solvents can be present in the composition in an amount up to 95% by weight of the total composition. The solvent is substantially removed when the coated silver nanoparticle dispersion is applied to the substrate 1 and dried.
Examples of the solvent used in the overcoat layer composition include methyl acetate, ethyl acetate, isopropyl acetate, tetrahydrofuran, 1,3-dioxolane, acetone, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, 2-propanol, 1-butanol or the like can be used. The solvent is not limited to one type, and a plurality of solvents may be mixed and used. Moreover, it is preferable to contain 80 wt% or more of these solvents.

  In the present embodiment, in addition to the components described above, if necessary, compatible additives such as a plasticizer, a stabilizer, a surfactant, a leveling agent, a coupling agent, and the like are spoiled. It is possible to add in the range which is not. However, it is preferable not to add fillers for suppressing curling or increasing the hardness because it causes a decrease in transmittance and a problem in dispersibility.

Thus, each component is appropriately selected, and a coating liquid obtained by mixing at an arbitrary ratio is obtained by using known coating means such as a roll coater, a gravure coater, a micro gravure coater, a bar coater, a die coater, and a dip coater. After applying to the base material 1 and drying, UV (ultraviolet) is irradiated.
Moreover, you may apply | coat two layers at once using a multilayer die coater. Hereinafter, this method will be described in detail.

Two layers of a silver nanoparticle resin layer composition comprising a coated silver nanoparticle, a dispersion solvent, and a solvent-soluble methacrylic acid ester or acrylic acid ester copolymer, and a layer comprising an overcoat layer composition Apply at once with a multilayer die coater.
Subsequently, the applied two layers are simultaneously dried to first form the silver nanoparticle resin layer 2.
Thereafter, the overcoat layer 3 is formed by subjecting the layer made of the composition for the overcoat layer to irradiation treatment with ionizing radiation such as ultraviolet rays and electron beams.

As described above, as a result of earnest research in view of the conventional problems, when producing silver nanoparticles by decomposing a silver compound as a raw material of silver, an alkyldiamine having a primary amine and a tertiary amine is used. When used by interposing, coated silver nanoparticles that can be dispersed in an organic solvent such as toluene even at a concentration of 50 wt% or more can be obtained. Further, when the dispersion concentration of the coated silver nanoparticles was changed, a coating film having a color corresponding to the concentration was obtained.
However, the film formed only with the coated silver nanoparticles is peeled off from the base material only by touching with a finger, and it cannot be realized as a functional film without adding a component for increasing the film strength and adhesion to the base material. . Therefore, in order to increase the film strength and the adhesion to the substrate, when other components are added, the dispersibility deteriorates according to the additive concentration, and the coated silver nanoparticles cannot obtain a coating film with a high concentration. . In order to increase the film strength and the adhesion to the base material with a high-concentration silver coating film, a multilayer structure composed of the silver nanoparticle resin layer 2 and the overcoat layer 3 is required.

More specifically, for example, silver oxalate is used as a silver compound as a raw material of silver, and the primary amine of the alkyldiamine is contained in a silver atom contained in silver oxalate by interposing N, N-dialkylaminoalkylamine. By preparing a complex compound in which an amino group moiety is coordinated and thermally decomposing the oxalate ion moiety constituting silver oxalate in this state, coated silver nanoparticles can be prepared in high yield. The coated silver nanoparticles have excellent dispersibility in non-polar solvents such as toluene because the non-complexed tertiary amino groups face the outermost surface of the particles, and also disperse in polymers with carboxy groups in the side chains. It can be prepared as a liquid.
Thus, the functional layer which has various optical characteristics was obtained by changing dispersion liquid concentration and coating film thickness. On the other hand, if the overcoat layer 3 is applied and cured on the silver nanoparticle resin layer 2 composed of the coated silver nanoparticles, the film strength is high if an ionizing radiation called a so-called hard coat agent, especially a material that can be cured by ultraviolet irradiation is applied and cured. A silver nanoparticle laminated film 5 having strong substrate adhesion could be obtained.

(Effect of this embodiment)
(1) A silver nanoparticle laminate 6 according to this embodiment is formed on a base material 1, a silver nanoparticle resin layer 2 containing silver nanoparticles, and a silver nanoparticle resin layer 2 formed on the base material 1. And an overcoat layer 3 including a three-dimensional crosslinked structure formed by ionizing radiation irradiation.
With such a configuration, since the overcoat layer 3 is provided, the scratch resistance of the silver nanoparticle laminate 6 can be improved.

(2) Moreover, the silver nanoparticle 4 contained in the silver nanoparticle resin layer 2 according to the present embodiment is covered with a protective molecule, and the protective molecule is an alkyldiamine having a primary amino group and a tertiary amino group. May be included as a main component.
If it is such a structure, when the silver nanoparticle 4 is disperse | distributed to the polymer which has nonpolar solvents, such as toluene, and a carboxy group in a side chain, the dispersibility will become favorable.

(3) Moreover, the overcoat layer 3 contained in the silver nanoparticle laminated body 6 which concerns on this embodiment may contain resin which has a three-dimensional crosslinked structure which has a urethane bond.
With such a configuration, the film strength of the overcoat layer 3 and the adhesion with the silver nanoparticle resin layer 2 can be further enhanced. Therefore, the scratch resistance of the silver nanoparticle laminate 6 can be further improved.

(4) The copolymer of the (meth) acrylate ester having a carboxy group in the side chain contained in the silver nanoparticle resin layer 2 according to the present embodiment and having a solvent solubility contains a carboxy group in the side chain. Any combination of monomers may be used. By selecting the monomer constituting the copolymer, the mechanical properties of the silver nanoparticle resin layer 2 such as hardness and elongation and the thermal properties such as adjustment of the glass transition point can be controlled.

(5) Moreover, 30 nm or less may be sufficient as the average particle diameter of the silver nanoparticle 4 contained in the silver nanoparticle resin layer 2 which concerns on this embodiment.
If it is such a structure, when the silver nanoparticle 4 is disperse | distributed in a solvent, the dispersibility will become favorable.

(6) Moreover, the silver nanoparticles 4 contained in the silver nanoparticle resin layer 2 according to the present embodiment may be dispersible in an organic solvent.
If it is such a structure, when the silver nanoparticle 4 is disperse | distributed in the organic solvent, the dispersibility will become favorable.

(7) Moreover, the overcoat layer 3 contained in the silver nanoparticle laminated body 6 which concerns on this embodiment may also contain a photoinitiator.
Even with such a configuration, the scratch resistance of the silver nanoparticle laminate 6 is enhanced.

(8) In the method for producing the silver nanoparticle laminate 6 according to this embodiment, a silver nanoparticle 4, a dispersion solvent, and a composition containing a polymer having a carboxy group in a side chain are applied onto a substrate and dried to form silver. An overcoat layer composition comprising a step of forming a nanoparticle resin layer 2, a compound having at least two polymerizable unsaturated double bonds in the molecule, a photopolymerization initiator, and a solvent. A step of forming the overcoat layer 3 by curing the overcoat layer composition after being applied onto the particle resin layer 2 and dried.
With such a configuration, since the overcoat layer 3 is provided, the scratch resistance of the silver nanoparticle laminate 6 can be improved.

(9) Another method for producing the silver nanoparticle laminate 6 according to the present embodiment is a silver nanoparticle resin layer containing, on the substrate 1, silver nanoparticles 4, a dispersion solvent, and a polymer having a carboxy group in a side chain. From the composition for overcoat layers containing the silver nanoparticle resin layer 2 composed of the composition for use, a compound having at least two polymerizable unsaturated double bonds in the molecule, a photopolymerization initiator, and a solvent. The overcoat layer 3 is formed of, for example, a multi-layer die coater simultaneously in this order, the silver nanoparticle resin layer 2 made of the silver nanoparticle resin layer composition, and the overcoat layer composition. The step of simultaneously drying the overcoat layer 3 and the step of forming the overcoat layer 3 by curing the overcoat layer 3 made of the dried composition for overcoat layer.
If it is such a structure, since it has the overcoat layer 3, the abrasion resistance of the silver nanoparticle laminated body 6 can be improved because this serves as a protective layer.

(10) Moreover, in the manufacturing method of the silver nanoparticle laminated body 6 which concerns on this embodiment, even if a solvent contains 80 wt% or more of methyl ethyl ketone, ethyl acetate, and mixtures thereof, or methyl ethyl ketone or ethyl acetate. Good.
With such a configuration, a compound having at least two polymerizable unsaturated double bonds in the molecule can be easily dissolved.

As described above, according to the present embodiment, the above-described problems of the prior art are solved, and the silver nanoparticles are sufficiently dispersed during the production process and storage, and aggregation thereof is prevented.
Also, a silver nanoparticle laminated film obtained by laminating an overcoat layer 3 having good film strength and adhesion to the silver nanoparticle resin layer 2 on the silver nanoparticle resin layer 2 formed using the silver nanoparticles. 5 and a method for producing a silver nanoparticle laminate 6 including the silver nanoparticle laminate film 5 can be provided.

(Modification)
In this embodiment, although the case where the covering silver nanoparticle which is the silver nanoparticle which coat | covered the surface with the protection molecule was used was demonstrated, this invention is not limited to this. Even if the silver nanoparticles are not coated with a protective molecule, the dispersibility is inferior to that of the coated silver nanoparticles, but can be used for the silver nanoparticle laminate 6 described above.

  In the following, the production method of silver nanoparticles, dispersibility in a solvent, preparation of a coating liquid for coating film formation, evaluation of physical properties of the coating film, etc. are shown as examples, but the present invention is limited to these. is not.

(Example 1 to Example 5)
[Synthesis of silver oxalate]
Distilled water (60 mL) was added to 9.92 g of oxalic acid dihydrate (Kanto Chemical Co., Ltd.) and dissolved while heating. While stirring in an oil bath at 110 ° C., 20 mL of silver nitrate (Kanto Chemical Co., Ltd.) (26.7 g) Distilled water was added and dissolved while heating, and stirring was continued for 1 hour. The precipitated silver oxalate was recovered by natural filtration, and further filtered and washed with 200 mL of hot water and 50 mL of methanol (Kanto Chemical Co., Ltd.), and then dried at room temperature while reducing the pressure in a shading desiccator. The yield of silver oxalate thus obtained was 21.6 g (yield 90.4%).

[Synthesis of coated silver nanoparticles]
When 0.13 g of oleic acid was added to 3.26 g of N, N-diethyl-1,3-diaminopropane (Tokyo Kasei Co., Ltd.), 1.90 g of silver oxalate obtained in the above-mentioned step was added, and 110 ° C. The mixture was heated and stirred in an oil bath. Within 1 minute, carbon dioxide bubbling occurred and after a few minutes turned into a brown suspension. After heating for 5 minutes, 30 mL of methanol was added to the cooled place, and the precipitate obtained by centrifugation was naturally dried to obtain 1.48 g of a blue solid (silver reference yield: 97.0).

  The obtained coated silver nanoparticles were observed in a S-TEM mode (acceleration voltage 30 kV) using a scanning electron microscope (Hitachi High-Technology Corporation, SEM S-4800). Particles were observed. The result is shown in FIG. More specifically, FIG. 2 is a scanning electron microscope image of silver nanoparticles observed after the toluene solvent dispersion of the coated silver nanoparticles obtained in Example 1 was dropped on a substrate (copper mesh / microgrid) and dried. .

  Next, the dispersibility of the obtained coated silver nanoparticles in a solvent was evaluated. As a result, toluene, cyclohexanone, terpineol C (Nippon Terpene Chemical Co., Ltd.), dihydroterpineol (Nippon Terpene Chemical Co., Ltd.), and a mixed solvent with hexane or the like containing these as a main component were well dispersed. Dynamic light scattering particle size measurement (Nikkiso, Nanotrac UPA-EX150) of the toluene dispersion solution showed that the obtained coated silver nanoparticles were well dispersed with an average particle size of 15 nm. The result is shown in FIG. Further, the solid line shown in FIG. 3 indicates the cumulative frequency (%).

[Synthesis of polymer having carboxy group in side chain]
The reaction vessel was charged with 800 parts of toluene, heated to 80 ° C. while injecting nitrogen gas into the vessel, and a mixture of the following monomer and thermal polymerization initiator was added dropwise at the same temperature over 1 hour to carry out the polymerization reaction. .

Styrene 60.0 parts Methacrylic acid 60.0 parts Methyl methacrylate 65.0 parts Butyl methacrylate 65.0 parts Azobisisobutyronitrile 10.0 parts After dropwise addition, the mixture is further reacted at 80 ° C for 3 hours, and then azo A solution obtained by dissolving 2.0 parts of bisisobutyronitrile in 50 parts of toluene was added, and the reaction was further continued at 80 ° C. for 1 hour to synthesize a resin solution.

  After cooling to room temperature, about 2 g of the resin solution was sampled and heated and dried at 180 ° C. for 20 minutes to measure the nonvolatile content. Toluene was added to the previously synthesized resin solution so that the nonvolatile content was 20%. An acrylic resin solution “A-1” was prepared.

[Formation of silver nanoparticle resin layer 2]
The silver solid obtained in the above step was dispersed in 2.0 g of toluene (Kanto Chemical Co., Inc.) and stirred well. A particle resin layer coating solution was obtained.
Here, five types of silver nanoparticle resin layer coating liquids having different amounts of blue solids were prepared and used in Examples 1 to 5, respectively. The amount of the blue solid added was 1.25% by weight (silver amount with respect to toluene) in Example 1, and the amount added in stages was increased in this order in Examples 2 to 5 (2.5, 5.0). 10.0, 20.0% by weight).

  After applying the silver nanoparticle resin layer coating solution containing the coated silver nanoparticles obtained in the above-described process to a 75 μm-thick PET film (Lumirror T60, Toray Industries, Inc.) using a # 10 bar coater, in an oven at 90 ° C for 1 minute The solvent was volatilized.

Next, “B-1” obtained by dissolving 9.5 g of urethane acrylate oligomer UA306I (Kyoeisha Chemical Co., Ltd.) and 0.50 g of Irgacure 184 (BASF Corp.) as an initiator in 12.0 g of methyl ethyl ketone is used as the above PET film. On the silver nanoparticle resin layer 2 containing the coated silver nanoparticles coated and dried, a # 10 bar coater was applied and dried.
Thereafter, the coated film was put in a purge box and nitrogen gas was sealed, and then exposed at 180 mJ / cm ² with a UV conveyor (Helius, CV-110Q-G type, light source: light hammer 10 Merck, H bulb), The “B-1” was cured to form an overcoat layer 3. The transmitted light of the thus obtained silver nanoparticle multilayer film 5 (hereinafter also simply referred to as “cured film”) was reddish purple. The evaluation results of the cured film 5 are shown in Table 1 below.

  Specifically, as an adhesion test, cellotape (registered trademark) was applied and peeled off, and the presence or absence of peeling was evaluated. “◎” indicates that the overcoat layer / silver nanoparticle resin layer does not peel off from the PET base material, and “○” indicates that the part of the overcoat layer / silver nanoparticle resin layer does not peel off from the PET base material. In the overcoat layer / silver nanoparticle resin layer, partly peeled off was indicated as “Δ” and peeled off was indicated as “x”.

Next, as an abrasion resistance test, the presence or absence of scratches when 10 reciprocations were applied while applying a load of 250 g / cm ² using # 0000 steel wool was determined as “◎”, and there was no 250 g load scratch. Was marked with “◎” and scratched with “x”.

  Furthermore, as a curl test, one film after UV curing was cut into a 100 mm square, and the lifting of the opposite side when one side was suppressed was examined, and less than 10 mm was “◯”, and 10 mm or more was “x”. The absorption maximum wavelength (λmax) was determined from an absorption spectrum (measured using Shimadzu Corporation, UV-visible spectrophotometer UV-2600, absorbance mode).

(Example 6)
Of the "B-1" (overcoat layer composition) used in Example 2, 9.0 g of UV-1700B (Nippon Gosei Chemical Co., Ltd.) instead of 9.5 g of urethane acrylate oligomer UA306I (Kyoeisha Chemical Co., Ltd.) A cured film of Example 6 was obtained in the same manner as in Example 2 except that 1.0 g of light acrylate PE-3A (pentaerythritol triacrylate, Kyoeisha Chemical Co.) was used. The evaluation results of the silver nanoparticle multilayer film 5 according to Example 6 are shown in Table 1.

(Example 7)
Instead of “A-1” (acrylic resin solution) used in Example 2, 20% toluene solution 5.0 g “A-2” of Hyperl MA4620 (manufactured by Negami Kogyo) was used. The silver nanoparticle multilayer film 5 of Example 7 was obtained. The evaluation results of the silver nanoparticle multilayer film 5 according to Example 7 are shown in Table 1.

(Comparative Example 1)
Among the “A-1” (acrylic resin solution) used in Example 2, a monomer from which methacrylic acid was removed (styrene; 60.0 parts, methyl methacrylate; 65.0 parts butyl methacrylate; 65 parts) was used. Then, an acrylic resin solution “C” was prepared and an attempt was made to prepare a silver nanoparticle resin layer coating solution. However, the silver nanoparticles aggregated and settled, and the silver nanoparticle resin layer coating solution could not be prepared. Therefore, it was not possible to evaluate the adhesion and scratch resistance among the above evaluation items.

(Comparative Example 2)
Of the “B-1” (composition for overcoat layer) used in Example 2, instead of 9.5 g of urethane acrylate oligomer UA306I (Kyoeisha Chemical Co., Ltd.), light acrylate DPE-6A (dipentaerythritol hexaacrylate, Kyoeisha Chemical Co., Ltd.) A cured film layer was obtained in the same manner as in Example 2 except that 9.5 g of the mixture “D” was used. The evaluation results of the silver nanoparticle multilayer film 5 according to Comparative Example 2 obtained in this way are shown in Table 1.

From the results shown in Table 1, it can be seen that the silver nanoparticle multilayer films 5 of Examples 1 to 7 are excellent in both adhesion and scratch resistance.
Moreover, even if it forms in a film, it turns out that the silver nanoparticle laminated body 6 of Example 1- Example 7 is hard to curl.
Moreover, it turns out that the silver nanoparticle laminated film 4 of Example 1- Example 7 is especially excellent in abrasion resistance.
Moreover, it turns out that the silver nanoparticle laminated film 5 of Example 1- Example 3 and Example 7 is especially excellent in both scratch resistance and adhesiveness.
Moreover, it turns out that the maximum absorption wavelength of all Examples other than the comparative example 1 and a comparative example can be controlled by an acrylic resin.

  As described above, the results shown in Table 1 indicate that the silver nanoparticle resin layers 2 of Examples 1 to 7 each have high adhesion. More specifically, it can be seen that the adhesion of the silver nanoparticle resin layer 2 of Examples 1 to 3 is higher than the adhesion of the silver nanoparticle resin layer 2 of Examples 4 to 5. This result will be described with reference to FIG.

FIG. 1 is a cross-sectional view schematically illustrating a configuration of a silver nanoparticle laminate 6 including the silver nanoparticle resin layer 2 of Examples 1 to 7. As shown in the item of silver nanoparticles in Table 1, the silver nanoparticle resin layers 2 of Examples 1 to 3 are more silver nanoparticles than the silver nanoparticle resin layers 2 of Examples 4 to 5. 4 content is low. In this case, since the interval between the existing silver nanoparticles 4 is relatively wide, the resin component of the silver nanoparticle resin layer 2 enters between the silver nanoparticles 4 and reaches the surface of the substrate 1 as shown in FIG. It is considered that the adhesiveness of the silver nanoparticle resin layer 2 has increased.
On the other hand, the silver nanoparticle resin layer 2 of Examples 4 to 5 has a higher content of silver nanoparticles 4 than the silver nanoparticle resin layer 2 of Examples 1 to 3. In this case, since the interval between the silver nanoparticles 4 is relatively narrow, the resin component of the silver nanoparticle resin layer 2 cannot reach between the silver nanoparticles 4 and reaches the surface of the substrate 1 as shown in FIG. It is considered that the amount of the resin component is reduced and the adhesion of the silver nanoparticle resin layer 2 is relatively lowered.

In Example 6, “B-2” was used as the composition of the overcoat layer 3, and since it was not urethane acrylate, it is considered that the scratch resistance was somewhat lower than in other examples.
Moreover, although Example 7 uses "A-2" as a resin solution, since the dispersibility of the silver nanoparticle is good like "A-1", the adhesion is particularly excellent.

  As described above, the UV curable resin composition containing the coated silver nanoparticles in the present invention can produce a functional film having optical characteristics peculiar to silver nanoparticles or a coating film having metallic luster, depending on the application. The sintering temperature can be changed. Furthermore, in addition to the silver nanoparticles and the dispersant, the composition does not aggregate even when a resin component for increasing the film strength and adhesion to the substrate is added.

DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Silver nanoparticle resin layer 3 ... Overcoat layer 4 ... Silver nanoparticle 5 ... Silver nanoparticle laminated film (or cured film)
6 ... Silver nanoparticle laminate

Claims (7)

A substrate;
A resin layer formed on the substrate and containing silver nanoparticles;
A silver nanoparticle laminate comprising: an overcoat layer including a three-dimensional cross-linked structure formed on the resin layer containing the silver nanoparticles and obtained by irradiation with ionizing radiation. The silver nanoparticles are covered with protective molecules,
The silver nanoparticle laminate according to claim 1, wherein the protective molecule contains, as a main component, an alkyldiamine having a primary amino group and a tertiary amino group.   3. The silver according to claim 1, wherein the resin layer containing silver nanoparticles contains a copolymer of a solvent-soluble (meth) acrylic acid ester having a carboxy group in a side chain as a main component. 4. Nanoparticle laminate.   The silver nanoparticle laminate according to any one of claims 1 to 3, wherein the overcoat layer includes a resin having a three-dimensional cross-linked structure having a urethane bond.   The silver nanoparticle laminate according to any one of claims 1 to 4, wherein an average particle diameter of the silver nanoparticles is 30 nm or less. A silver nanoparticle resin layer composition comprising silver nanoparticles, a dispersion solvent, and a solvent-soluble (meth) acrylic acid ester copolymer having a carboxy group in the side chain is applied onto a substrate and dried. Forming a silver nanoparticle resin layer;
A composition for an overcoat layer containing a compound having at least two polymerizable unsaturated double bonds in the molecule, a photopolymerization initiator, and a solvent is applied onto the silver nanoparticle resin layer and dried. And a step of curing the overcoat layer composition to form an overcoat layer. A method for producing a silver nanoparticle laminate, comprising: A layer comprising a silver nanoparticle resin layer composition comprising a silver nanoparticle, a dispersion solvent, a solvent-soluble (meth) acrylic acid ester copolymer having a carboxy group in a side chain, and a molecule A step of simultaneously forming a layer comprising a composition for an overcoat layer containing at least two polymerizable unsaturated double bonds therein, a photopolymerization initiator, and a solvent in this order;
A step of simultaneously drying the layer made of the composition for a silver nanoparticle resin layer and the layer made of the composition for an overcoat layer;
And a step of curing the dried layer made of the composition for an overcoat layer to form an overcoat layer.