JP7420762B2 - ink composition - Google Patents

Description

The present invention relates to a silver luster ink composition for metallically decorating various objects to be decorated.

Metallic decoration is needed in a wide range of fields, such as automobile interior and exterior parts, emblems, electronic devices, cosmetic containers, and golf club shafts. A high level of metallic luster is required. In particular, silver has a beautiful metallic luster (metallicity, glitter, specularity) due to its high light reflectance, and is expected to be a metal suitable for advanced design.

Techniques for imparting metallic luster to objects to be decorated include foil stamping, vapor deposition, silver mirror plating using silver mirror reaction, and chrome plating, as well as inks using aluminum pigments as bright pigments and inks containing metal nanoparticles. Examples include a method of forming a metallic luster layer on a base material by printing or coating.

Foil stamping, vapor deposition, silver mirror plating, and chrome plating can give a metallic luster close to that of metal, but these methods are disadvantageous in terms of manufacturing costs because the manufacturing process is complicated and special equipment is required. It is. In addition, silver mirror plating has a high defect rate due to whitening, cracking, and uneven coloring that are characteristic of plating, and because parts other than those to be plated are plated. Furthermore, chrome plating has a large impact on the environment. In contrast to these methods, methods such as printing and coating using ink have lower manufacturing costs and can be applied to a wide range of base materials.

Among inks, a metallic luster layer made of an ink containing metal nanoparticles has better metallic luster than an ink using an aluminum pigment (bright pigment).

JP-A-2009-227736 (Patent Document 1) contains metal colloid particles formed of metal nanoparticles and a dispersant; and a solvent (B), and the dispersant contains an organic compound having a carboxyl group and a polymer. Inkjet printing ink compositions are described that include molecular dispersants. This document also describes that additives such as binder resins (hydrophilic polymers such as polyvinyl alcohol and polyethylene glycol) may be added.

JP 2017-149942A (Patent Document 2) discloses an ink composition for printing or printing on a printing material, which includes silver nanoparticles, a dispersant having a carboxyl group or a salt thereof, and an aqueous solvent. discloses an ink composition containing 1 to 30 parts by mass of a water-soluble or water-dispersible polymer having a film-forming ability based on 100 parts by mass of silver nanoparticles in terms of solid content. .

JP 2018-153965A (Patent Document 3) discloses an image formed product having a base material and a metallic luster layer formed on the base material, wherein the metallic luster layer includes metal nanoparticles and the metallic luster layer formed on the base material. The polymer dispersant is a compound having an acid value of 1 or more and 80 or less, and the binder resin has an SP value of 23. An image-formed product is disclosed in which the resin has a molecular weight of 0 or more and 26.0 or less. This document describes the binder resin as polyvinyl alcohol having a saponification degree of 72 or more and 85 or less.

JP 2018-145319 A (Patent Document 4) discloses that first resin particles containing water, a water-soluble organic solvent with a boiling point of 250° C. or less, a glitter pigment, and a vinyl polymer, and second resin particles are used. An ink containing the invention is disclosed. This document describes a silver colloid particle dispersion as a glittering pigment.

JP 2019-116522A (Patent Document 5) discloses an ink containing silver particles having a particle size Dav90 of 45 nm or less, a polyol, a silicone surfactant, and a resin. This document describes that the ink contains a water-soluble resin or a water-dispersible resin.

JP 2017-2219 A (Patent Document 6) discloses an alcohol solution in which a polymer dispersant is dissolved in an alcohol solvent and at least one silver compound selected from silver oxide and silver carbonate is dispersed. A composition liquid for forming a silver mirror film layer is disclosed, which is made of a dispersion solution of silver nanoparticles and obtained by irradiating ultrasonic waves into the alcohol solution.

Japanese Patent Application Publication No. 2009-227736 Japanese Patent Application Publication No. 2017-149942 Japanese Patent Application Publication No. 2018-153965 Japanese Patent Application Publication No. 2018-145319 JP2019-116522A JP 2017-2219 Publication

However, in the inks using metal nanoparticles disclosed in Patent Documents 1 to 6, if the amount of resin such as a binder is increased, metallic luster (silver luster) cannot be obtained. It was necessary to reduce the amount as much as possible. If the amount of resin is reduced, the adhesion to the base material and scratch resistance will decrease, so it has been necessary to use the resin in combination with an overcoat layer and an undercoat layer. That is, since there is a trade-off relationship between metallic luster and adhesion, it has been difficult to achieve both properties using a simple method.

Therefore, an object of the present invention is to provide an ink composition that can achieve both silver luster, adhesion, and scratch resistance.

As a result of intensive studies to achieve the above object, the present inventors have found that silver luster can be improved by combining composite nanoparticles of silver-containing metal and protective colloid, non-silicone resin, silicone resin, and solvent. The present invention was completed by discovering that both adhesion and scratch resistance can be achieved.

That is, the ink composition of the present invention includes composite nanoparticles (A) of a metal containing silver and a protective colloid, a non-silicone resin (B), a silicone resin (C), and a solvent (D). The mass ratio of the non-silicone resin (B) and the silicone resin (C) may be former/latter = 95/5 to 5/95. The total proportion of the non-silicone resin (B) and the silicone resin (C) may be 10 to 300 parts by mass based on 100 parts by mass of the silver-containing metal of the composite nanoparticles (A). . The non-silicone resin (B) may be a resin having a hydroxyl group. The non-silicone resin (B) may be at least one selected from the group consisting of (meth)acrylic resin, polyvinyl acetal resin, and polyester resin. The solvent (D) may contain at least one selected from the group consisting of esters, alkylene glycol monoalkyl ethers, and dialkylene glycol monoalkyl ethers. The composite nanoparticles (A) may be particles in which a protective colloid is attached or coordinated to the surface of silver nanoparticles. The silver nanoparticles may have an average particle size of 1 to 100 nm. The protective colloid may contain a polymeric dispersant having a carboxyl group or a salt thereof.

In the present invention, since composite nanoparticles of a metal containing silver and a protective colloid, a non-silicone resin, a silicone resin, and a solvent are combined, it is possible to achieve both silver luster, adhesion, and scratch resistance. Specifically, it is possible to form a silver glossy film with high adhesion on the object to be decorated without forming a top coat or undercoat layer, so it is possible to improve adhesion with a simple method and improve scratch resistance. can. Furthermore, since a dense layer of silver-containing nanoparticles can be formed on the surface of the film, the light shielding property (non-transmission) is great and the silver luster (mirror surface) can be improved.

FIG. 1 shows a transmission electron microscope (TEM) image of a cross section of the silver glossy film obtained in Example 1. FIG. 2 is an enlarged image of the TEM image of FIG. 1 near the surface. FIG. 3 is an enlarged image of the TEM image of FIG. 1 near the interface with the base material. FIG. 4 is an enlarged image of the TEM image of FIG. 1 near the center of the film thickness. FIG. 5 shows a TEM image of a cross section of the silver glossy film obtained in Example 2. FIG. 6 is an enlarged image of the vicinity of the surface in the TEM image of FIG. FIG. 7 is an enlarged image of the vicinity of the interface with the base material in the TEM image of FIG. FIG. 8 is an enlarged image of the TEM image of FIG. 5 near the center of the film thickness. FIG. 9 shows a TEM image of a cross section of the silver glossy film obtained in Example 4. FIG. 10 is an enlarged image of the TEM image of FIG. 9 near the surface. FIG. 11 is an enlarged image of the vicinity of the interface with the base material in the TEM image of FIG. FIG. 12 is an enlarged image of the TEM image of FIG. 9 near the center of the film thickness. FIG. 13 shows a TEM image of a cross section of the silver glossy film obtained in Example 7. FIG. 14 is an enlarged image of the TEM image of FIG. 13 near the surface. FIG. 15 is an enlarged image of the TEM image of FIG. 13 near the interface with the base material. FIG. 16 is an enlarged image of the TEM image of FIG. 13 near the center of the film thickness. FIG. 17 shows a TEM image of a cross section of the silver glossy film obtained in Example 8. FIG. 18 is an enlarged image of the TEM image of FIG. 17 near the surface. FIG. 19 is an enlarged image of the TEM image of FIG. 17 near the interface with the base material. FIG. 20 is an enlarged image of the TEM image of FIG. 17 near the center of the film thickness. FIG. 21 shows a TEM image of a cross section of the silver glossy film obtained in Example 11. FIG. 22 is an enlarged image of the TEM image of FIG. 21 near the surface. FIG. 23 is an enlarged image of the TEM image of FIG. 21 near the interface with the base material. FIG. 24 is an enlarged image of the TEM image of FIG. 21 near the center of the film thickness. FIG. 25 shows a TEM image of a cross section of the silver glossy film obtained in Example 13. FIG. 26 is an enlarged image of the TEM image of FIG. 25 near the surface. FIG. 27 is an enlarged image of the TEM image of FIG. 25 near the interface with the base material. FIG. 28 is an enlarged image of the TEM image of FIG. 25 near the center of the film thickness. FIG. 29 shows a TEM image of a cross section of the silver glossy film obtained in Example 20. FIG. 30 is an enlarged image of the TEM image of FIG. 29 near the surface. FIG. 31 is an enlarged image of the TEM image of FIG. 29 near the interface with the base material. FIG. 32 is an enlarged image of the TEM image of FIG. 29 near the center of the film thickness. FIG. 33 shows a TEM image of a cross section of the silver glossy film obtained in Comparative Example 1. FIG. 34 is an enlarged image of the TEM image of FIG. 33 near the surface. FIG. 35 is an enlarged image of the vicinity of the interface with the base material in the TEM image of FIG. 33. FIG. 36 is an enlarged image of the TEM image of FIG. 33 near the center of the film thickness. FIG. 37 shows a TEM image of a cross section of the silver glossy film obtained in Comparative Example 4. FIG. 38 is an enlarged image of the TEM image of FIG. 37 near the surface. FIG. 39 is an enlarged image of the TEM image of FIG. 37 near the interface with the base material. FIG. 40 is an enlarged image of the TEM image of FIG. 37 near the center of the film thickness.

[Ink composition]
In the ink (or ink) composition (or coating composition) of the present invention, by combining a non-silicone resin and a silicone resin as resin components, metallic luster (silver luster), adhesion and resistance are improved. The mechanism that can achieve both scratch resistance and abrasion resistance can be estimated as follows.

That is, the composite nanoparticles (A) of a metal containing silver (silver-containing metal) and a protective colloid exist in the composition in a compatible manner with the non-silicone resin (B) and the silicone resin (C). However, since the solubility (or affinity) of the protective colloid for the two types of resin components is different, the composite nanoparticles (A) are miscible with one of the resins that is easier to disperse. As a result, phase separation occurs inside the produced membrane, and the composite nanoparticles (A) become unevenly distributed. Specifically, when the solvent dries, two different types of resin components undergo phase separation on the scale of tens to hundreds of nanometers inside the membrane due to spinodal decomposition. That is, a phase-separated structure is formed into a phase containing a relatively large amount of composite nanoparticles (A) and a phase containing only a small amount. Furthermore, the phase containing a relatively large amount of composite nanoparticles (A) tends to be intensively dispersed (or migrated) to the surface of the membrane and the interface with the base material, and the phase contains a relatively large amount of composite nanoparticles (A). (This is presumed to be due to the tendency of components with low surface tension to float toward the surface layer, as it is more energetically stable when concentrated on the surface.) As a result, the composite nanoparticles (A) are aligned at the surface layer of the film and at the interface with the base material, thereby playing a role in blocking (not transmitting) light. Furthermore, phase separation may proceed inside the membrane to form a sea-island structure or a co-continuous structure, and by forming a phase separation structure inside the membrane, gloss can be further improved. In other words, by using two types of resin components, phase separation in which the composite nanoparticles (A) are unevenly distributed creates a shielding effect (non-permeability) not only at the surface layer of the membrane and the interface with the base material, but also inside the membrane. becomes high and develops a high degree of silver luster (mirror surface). In particular, regarding the phase separation structure inside the membrane, from the viewpoint of an excellent balance of various properties, a phase that forms a sea-island structure inside the membrane and contains a relatively large amount of composite nanoparticles (A) forms a dispersed phase. is preferable.

On the other hand, in conventional ink compositions containing only one type of resin component, metal particles such as silver-containing nanoparticles are uniformly dispersed (silver-containing nanoparticles interact with the surface layer of the film and the base material). (not unevenly distributed at the interface), there is no area where metal particles are concentrated that can block light. Therefore, it can be assumed that with the conventional ink composition, light easily passes through and silver luster cannot be obtained. Note that even if there is no phase separation of the resin component, the metal particles and the resin component may undergo phase separation, and in this case, it can be assumed that cloudiness occurs and the metallic luster disappears.

Furthermore, silver gloss ink (metallic ink) requires adhesion and scratch resistance in addition to silver gloss. Adhesion and scratch resistance can be improved by using a resin component (binder), but on the other hand, as the resin component increases, the proportion of silver decreases, so the light shielding effect of silver decreases and the silver luster decreases. descend. In the present invention, as described above, by utilizing phase separation in which composite nanoparticles (A) are unevenly distributed between two types of resin components, a phase that can shield light (a relatively large number of composite nanoparticles (A)) is utilized. Because of this, even if a large amount of the resin component is blended, high silver luster is produced. That is, by blending a large amount of resin component while maintaining a high degree of silver luster, adhesion and scratch resistance can be improved. Furthermore, topcoating and undercoating are no longer necessary, resulting in a simple structure that improves productivity and allows coating on various objects to be decorated (substrates or molded objects).

On the other hand, in conventional ink compositions, when the proportion of the resin component is small (the amount of the resin component relative to the metal containing silver is about 10% by mass or less), the gloss is high, but the adhesion and scratch resistance are low. In many cases, overcoat and undercoat layers were required. On the other hand, when the ratio of the resin component was high (the amount of the resin component relative to the silver-containing metal was about 10% by mass or more), the adhesion and scratch resistance improved, but the gloss decreased. Therefore, in conventional silver luster inks, it is necessary to keep the amount of resin to the metal containing silver to a small amount, and the amount of resin component to the metal containing silver is at most about 10% by mass, and the structure is simple. It was not possible to improve adhesion and scratch resistance.

(A) Composite Nanoparticles The ink composition (metallic ink composition) of the present invention includes composite nanoparticles (A) of a metal containing silver and a protective colloid.

In the composite nanoparticles (A), the composite form of the silver-containing metal (silver-containing metal) and the protective colloid is not particularly limited, and may be a composite attached or coordinated to the surface of the silver-containing metal nanoparticles. Alternatively, it may be a composite in which the surface of silver-containing metal nanoparticles is coated. Silver-containing metal nanoparticles have a high coordination ability with respect to protective colloids (or dispersants), so when the protective colloid coordinates to the surface of silver-containing metal nanoparticles, a composite coated with silver-containing metal nanoparticles can be formed. There may be. When silver-containing metal nanoparticles are composited with a protective colloid, the dispersion stability of silver-containing metal nanoparticles can be improved, and the affinity with (meth)acrylic resins and silicone resins can be easily adjusted. , can form a phase-separated structure.

(Silver-containing metal nanoparticles)
The silver-containing metal nanoparticles are nanometer sized. The number average particle size (number average primary particle size) of the silver-containing metal nanoparticles is, for example, 1 to 100 nm (for example, 2 to 80 nm), preferably 3 to 70 nm (for example, 4 to 50 nm), more preferably 5 to 40 nm (especially 10-30 nm).

The silver-containing metal nanoparticles have the above average particle size and exhibit a wide particle size distribution in the range of 200 nm or less, but may contain almost no coarse particles exceeding 200 nm. Therefore, the maximum primary particle size of the silver-containing metal nanoparticles is, for example, 200 nm or less, preferably 150 nm or less, and more preferably 100 nm or less.

In the silver-containing metal nanoparticles, the proportion of particles having a primary particle diameter of 100 nm or more is, for example, 10% by mass or less (for example, 0 to 8% by mass), preferably 5% by mass or less (for example, 0.01 to 3% by mass). % by mass), more preferably 1% by mass or less (for example, 0.02 to 0.5% by mass).

In addition, in this application, the particle size and particle size distribution of silver-containing metal nanoparticles can be measured using a transmission electron microscope, and the average particle size is shown as an average value of ten arbitrary particles.

(Metals including silver)
The metal containing silver (silver-containing metal) may be simple silver or may be an alloy of silver and other metals. Other metals are not particularly limited as long as they can be alloyed with silver, and examples thereof include Cr, Mo, W, Ni, Pd, Pt, Cu, Au, Zn, In, Sn, and Pb. These other metals can be used alone or in combination of two or more. Among these other metals, Cu is preferred.

Among the silver-containing metals, the proportion of silver may be 50% by mass or more, for example 90% by mass or more, preferably 95% by mass or more, more preferably 97% by mass or more, more preferably 99% by mass or more. % by mass or more, most preferably 100% by mass (single silver). If the proportion of silver is too low, there is a risk that the silver luster will be reduced.

When the silver-containing metal is a combination of silver and another metal (especially copper), the proportion of the other metal is, for example, 0.01 to 10 parts by mass, preferably 0.03 to 10 parts by mass, relative to 100 parts by mass of silver. The amount is 5 parts by weight, more preferably 0.05 to 3 parts by weight.

(protective colloid)
Protective colloids may be dispersants, and are often non-volatile dispersants. In particular, the protective colloid preferably contains a polymeric dispersant having a carboxyl group or a derivative group thereof. In addition, in this application, the carboxyl group also includes a carboxyl group in the form of an acid anhydride group.

The polymer dispersant (or polymer type dispersant) may have at least a carboxyl group and be capable of dispersing silver-containing metal nanoparticles, and may be an amphiphilic polymer dispersant (or oligomer type dispersant). It may be.

Examples of the polymer dispersant include polymer dispersants that are commonly used for dispersing colorants in the paint and ink fields. Typical polymeric dispersants (amphiphilic polymeric dispersants) include water-soluble or water-dispersible resins containing hydrophilic units (or hydrophilic blocks) formed from hydrophilic monomers.

Examples of the hydrophilic monomer include carboxyl group-containing monomers (unsaturated polycarboxylic acids such as (meth)acrylic acid, maleic acid, and maleic anhydride, or acid anhydrides thereof), monomers having sulfo groups, etc. addition-polymerizable monomers such as hydroxyl group-containing monomers (hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, vinyl phenol, etc.); condensation-polymerizable monomers such as ethylene oxide; For example, The condensation polymerizable monomer may form a hydrophilic unit (or block) by reaction with active hydrogen such as a hydroxyl group (for example, the hydroxyl group). The hydrophilic monomers may be used alone or in combination of two or more to form a hydrophilic unit (or block). Preferred hydrophilic monomers are (meth)acrylic acid, maleic acid, maleic anhydride, and ethylene oxide.

The polymer dispersant only needs to have at least a carboxyl group, and may have a functional group of the hydrophilic monomer, such as an acid group (sulfo group) or a hydroxyl group. These functional groups may be introduced into the polymer dispersant singly or in combination of two or more.

The polymeric dispersant may contain at least a hydrophilic unit (or hydrophilic block), may be a single or copolymer of hydrophilic monomers (for example, polyacrylic acid or a salt thereof, etc.), and may be a hydrophilic monomer. It may also be a copolymer of a hydrophobic monomer and a hydrophobic monomer. Hydrophobic monomers (nonionic monomers) include (meth)acrylic esters [methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate; , C _1-20 alkyl (meth)acrylates such as lauryl (meth)acrylate and stearyl (meth)acrylate, cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate, phenyl (meth)acrylate, etc. (meth)acrylic monomers such as aryl (meth)acrylate, benzyl (meth)acrylate, aralkyl (meth)acrylate such as 2-phenylethyl (meth)acrylate]; styrene, α-methylstyrene, Styrenic monomers such as vinyltoluene; Olefinic monomers such as α-C _2-20 olefins (ethylene, propylene, 1-butene, isobutylene, 1-hexene, 1-octene, 1-dodecene, etc.); vinyl acetate, vinyl butyrate addition-polymerizable monomers such as carboxylic acid vinyl ester monomers; and condensation-polymerizable monomers such as C _3-6 alkylene oxides such as propylene oxide. The hydrophobic monomers may be used alone or in combination of two or more to form a hydrophobic unit.

Polymeric dispersants for copolymers (e.g., copolymers of hydrophilic monomers and hydrophobic monomers) are random copolymers, alternating copolymers, block copolymers (e.g., hydrophilic blocks composed of hydrophilic monomers and hydrophobic monomers). (or a comb-shaped graft copolymer), or a comb-shaped copolymer (or a comb-shaped graft copolymer). The structure of the block copolymer is not particularly limited, and may be a diblock structure, a triblock structure (ABA type, BAB type), or the like. Further, in the comb-shaped copolymer, the main chain may be formed of the hydrophilic block or the hydrophobic block, or may be formed of the hydrophilic block and the hydrophobic block. A block copolymer of a hydrophilic block and a hydrophobic block can also improve silver luster.

Note that, as described above, the hydrophilic unit can also be formed from a hydrophilic block (such as polyalkylene oxide such as polyethylene oxide). The hydrophilic block (such as polyalkylene oxide) and the hydrophobic block (such as polyolefin block) may be bonded via a linking group such as an ester bond, amide bond, ether bond, or urethane bond. These bonds can be achieved, for example, by modifying hydrophobic blocks (such as polyolefins) with modifiers [unsaturated carboxylic acids or their anhydrides (such as maleic acid anhydride), lactams or aminocarboxylic acids, hydroxylamines, diamines, etc.] After that, it may be formed by introducing a hydrophilic block. In addition, a polymer obtained from a monomer having a hydrophilic group such as a hydroxyl group or a carboxyl group (such as the above-mentioned hydroxyalkyl (meth)acrylate) is reacted (or bonded) with the above-mentioned condensed hydrophilic monomer (such as ethylene oxide). In this way, a comb-shaped copolymer (a comb-shaped copolymer whose main chain is composed of hydrophobic blocks) may be formed.

Furthermore, the balance between hydrophilicity and hydrophobicity may be adjusted by using a hydrophilic nonionic monomer as a copolymerization component. Such components include monomers or oligomers having ethyleneoxy units such as 2-(2-methoxyethoxy)ethyl (meth)acrylate and polyethylene glycol mono(meth)acrylate (for example, number average molecular weight 200 to 1,000). Examples include: Furthermore, the balance between hydrophilicity and hydrophobicity may be adjusted by modifying (for example, esterifying) a hydrophilic group (such as a carboxyl group).

In a polymeric dispersant having a carboxyl group, the carboxyl group may be a salt or an acid anhydride group. For example, at least some of the carboxyl groups may form a salt (salt with an amine, metal salt, etc.). However, a polymeric dispersant in which acid groups such as carboxyl groups do not form salts (that is, polymeric dispersants having free carboxyl groups) can be preferably used.

The acid value of the polymer dispersant having a carboxyl group is, for example, 1 mgKOH/g or more (for example, 2 to 100 mgKOH/g), preferably 3 mgKOH/g or more (for example, 4 to 90 mgKOH/g), and more preferably 5 mgKOH/g or more ( For example, the amount may be 6 to 80 mgKOH/g), more preferably 7 mgKOH/g or more (for example, 8 to 50 mgKOH/g), and usually 3 to 30 mgKOH/g (especially 5 to 20 mgKOH/g). In addition, in such a polymeric dispersant, the amine value may be 0 (or almost 0).

In addition, in the said polymeric dispersant, the position of a functional group is not specifically limited, The main chain may be sufficient as it may be sufficient, and a side chain may be sufficient as it, and it may be located in a main chain and a side chain. Such a functional group may be, for example, a functional group derived from a hydrophilic monomer or a hydrophilic unit (for example, a functional group introduced by copolymerization of (meth)acrylic acid, maleic anhydride, ethylene oxide, etc.). good.

The polymer dispersants having carboxyl groups may be used alone or in combination of two or more.

As the polymer dispersant, a polymer dispersant (high molecular weight pigment dispersant) described in JP-A-2004-207558 and the like may be used. Further, the polymer dispersant may be synthesized or a commercially available product may be used. Specific examples of commercially available polymer dispersants (or dispersants made of at least amphiphilic dispersants) include Solsperse 13240, Solsperse 13940, Solsperse 32550, Solsperse 31845, Solsperse 24000, Solsperse 26000, Solsperse series such as Solsperse 27000, Solsperse 28000, Solsperse 41090 [manufactured by Avecia Co., Ltd.]; Disperbic 160, Disperbic 161, Disperbic 162, Disperbic 163, Disperbic 164, Disperbic 166, Disperbic 170, Disperbic Disperbic series [BIK Chemie ( EFKA-46, EFKA-47, EFKA-48, EFKA-49, EFKA-1501, EFKA-1502, EFKA-4540, EFKA-4550, Polymer 100, Polymer 120, Polymer 150, Polymer 400, Polymer 401, Polymer 402, Polymer 403, Polymer 450, Polymer 451, Polymer 452, Polymer 453 [manufactured by EFKA Chemical Co., Ltd.]; Ajisper series such as Ajisper PB711, Ajisper PAl11, Ajisper PB811, Ajisper PB821, Ajisper PW911 [Ajinomoto ( Floren series such as Floren DOPA-158, Floren DOPA-22, Floren DOPA-17, Floren TG-700, Floren TG-720W, Floren-730W, Floren-740W, Floren-745W [Kyoeisha Chemical Co., Ltd.]; (manufactured by Johnson Polymer Co., Ltd.); and Jonkryl series such as Jonkryl 678, Jonkryl 679, and Jonkryl 62 (manufactured by Johnson Polymer Co., Ltd.). Typical polymeric dispersants include Dispervic 190, Dispervic 194, Dispervic 2015, and the like.

The number average molecular weight of the polymer dispersant is, for example, 1,500 to 100,000, preferably 2,000 to 80,000 (for example, 2,000 60,000), more preferably 3,000 to 50,000 (for example 5,000 to 30,000), more preferably 7,000 to 20,000.

The polymer dispersant having a carboxyl group may be a polymer dispersant having no hydroxyl group.

The proportion of the protective colloid is, for example, 0.1 to 100 parts by weight (especially 1 to 50 parts by weight) per 100 parts by weight of the silver-containing metal. The proportion of the polymeric dispersant having a carboxyl group can be selected from a range of, for example, about 0.1 to 60 parts by mass (for example, 1 to 50 parts by mass), and usually 2 to 40 parts by mass, relative to 100 parts by mass of the silver-containing metal. parts (for example, 2.5 to 30 parts by weight), more preferably 3 to 25 parts by weight (especially 5 to 20 parts by weight).

In the present application, the proportion of the protective colloid in the composite nanoparticles (A) can be measured by a conventional method, for example, thermal analysis (for example, simultaneous thermogravimetric/differential thermal analysis).

The protective colloid may contain other dispersants, if necessary, and the other dispersants may be inorganic compounds, but are usually organic compounds. Other dispersants include, for example, alkanols ( _C6-20 alkane monools such as hexanol _, octanol, decanol, dodecanol, and octadecanol), aldehydes (C6-20 alkane monools such as capryaldehyde, laurylaldehyde, and palmitaldehyde). _-20 aliphatic aldehydes), aliphatic hydroxycarboxylic acids, higher fatty acids or their salts, and sulfonic acids (alkanesulfonic acids, benzenesulfonic acids, arenesulfonic acids such as toluenesulfonic acids, etc.). These other dispersants may be used alone or in combination of two or more.

The proportion of other dispersants is, for example, 0.1 to 100 parts by weight, preferably 0.5 to 50 parts by weight, and more preferably 1 to 30 parts by weight, based on 100 parts by weight of the polymeric dispersant.

The method for producing the composite nanoparticles is not particularly limited, and may be a conventional method. For example, when the silver-containing metal is simple silver, a silver compound corresponding to the silver nanoparticles is mixed in the presence of a protective colloid and a reducing agent, It can be prepared by reduction in a solvent. Specific manufacturing methods include, for example, the methods described in JP-A-2010-80442 and JP-A-2010-229544.

(B) Non-silicone resin The ink composition of the present invention further contains a non-silicone resin (B) in addition to the composite nanoparticles (A). Since the non-silicone resin has a high affinity for the silver-containing metal nanoparticles (especially the composite nanoparticles (A)), in combination with the silicone resin (C) which has a low affinity as described below, the non-silicone resin A phase-separated structure can be formed inside.

The non-silicone resin (B) may be a silicon-free resin. Furthermore, the non-silicone resin (B) has a high affinity for silver-containing metal nanoparticles (particularly composite nanoparticles (A)), and can be easily cured with a curing agent depending on the application. (silicon-free resin having a hydroxyl group) is preferable, and polyols (especially isocyanate-curable polyols) are particularly preferable.

Specific examples of non-silicone resins (B) include (meth)acrylic resins (B1) and polyvinyl acetal resins, since they are easy to form a silver gloss film that can achieve both silver luster, adhesion, and scratch resistance. At least one selected from the group consisting of resin (B2) and polyester resin (B3) is preferred.

(B1) (meth)acrylic resin The (meth)acrylic resin (B1) is not particularly limited, but includes, for example, a single or copolymer of (meth)acrylic monomer, (meth)acrylic polyol, modified (meth) ) It may be an acrylic resin.

Examples of (meth)acrylic monomers include (meth)acrylic acid; methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. , C _1-20 alkyl (meth)acrylates such as lauryl (meth)acrylate and stearyl (meth)acrylate; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate; phenyl (meth)acrylate, etc. Aryl (meth)acrylates; Aralkyl (meth)acrylates such as benzyl (meth)acrylate and 2-phenylethyl (meth)acrylate; Hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, etc. Examples include hydroxy C _1-4 alkyl (meth)acrylate. These (meth)acrylic monomers can be used alone or in combination of two or more. Among these, C _1-4 alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate; hydroxyC _2-3 such as hydroxyethyl (meth)acrylate Alkyl (meth)acrylates are preferred.

Although the (meth)acrylic resin (B1) may be a homopolymer of these monomers, a copolymer is preferable. The copolymer may be a copolymer of two or more of the above (meth)acrylic monomers, and a copolymer of the above (meth)acrylic monomer and a copolymerizable monomer. It may be. Examples of copolymerizable monomers include styrene monomers such as styrene, α-methylstyrene, and vinyltoluene; α-C _2-20 olefins (ethylene, propylene, 1-butene, isobutylene, 1-hexene, (1-octene, 1-dodecene, etc.); and addition-polymerizable monomers such as carboxylic acid vinyl ester monomers such as vinyl acetate and vinyl butyrate. These copolymerizable monomers can be used alone or in combination of two or more. Among these, styrenic monomers such as styrene are preferred.

When the (meth)acrylic resin is a copolymer of a (meth)acrylic monomer and a styrene monomer (especially a copolymer of a methacrylic monomer and a styrene monomer), The molar ratio of the (meth)acrylic monomer to the styrene monomer is former/latter = 95/5 to 5/95, preferably 90/10 to 10/90, more preferably 80/20 to 20. /80, more preferably 70/30 to 30/70.

The (meth)acrylic polyol is not particularly limited as long as it is a (meth)acrylic polymer having two or more hydroxyl groups in the molecule. For example, hydroxy C _2- as a monomer of the (meth)acrylic resin It may also be a (meth)acrylic resin containing _3- alkyl (meth)acrylate.

Examples of modified (meth)acrylic resins include polyester modified (meth)acrylic resins such as polyester (meth)acrylate, polyurethane modified (meth)acrylic resins such as urethane (meth)acrylate, and epoxy (meth)acrylate. Examples include epoxy-modified (meth)acrylic resins such as epoxy-modified (meth)acrylic resins, and silicone-modified (meth)acrylic resins such as silicone (meth)acrylate. These modified (meth)acrylic resins can be used alone or in combination of two or more.

These (meth)acrylic resins can be used alone or in combination of two or more. Among these, (meth)acrylic resins having hydroxyl groups ( In particular, (meth)acrylic resins having multiple hydroxyl groups such as isocyanate-curable (meth)acrylic resins are preferred, and (meth)acrylic resins having hydroxyl groups and styrene units (for example, methyl (meth)acrylate-hydroxy Particularly preferred are alkyl (meth)acrylate-styrene copolymers, etc.). Note that the position of the hydroxyl group is not particularly limited, and it may be located on the main chain, on the side chain, or on the main chain and the side chain.

The hydroxyl value of the (meth)acrylic resin (B1) is, for example, 1 mgKOH/g or more (for example, 2 to 400 mgKOH/g), preferably 3 mgKOH/g or more (for example, 4 to 300 mgKOH/g), more preferably 5 mgKOH/g or more. (for example, 6 to 200 mgKOH/g), more preferably 7 mgKOH/g or more (for example, 8 to 150 mgKOH/g), and usually 10 to 150 mgKOH/g (especially 50 to 100 mgKOH/g).

The weight average molecular weight of the (meth)acrylic resin (B1) is, for example, 1,000 to 100,000, preferably 2,000 to 80,000 (in terms of polystyrene) when measured by gel permeation chromatography (GPC). For example, 3,000 to 50,000), more preferably 5,000 to 30,000 (eg, 10,000 to 20,000), and more preferably 12,000 to 16,000.

The glass transition temperature of the (meth)acrylic resin (B1) is, for example, 0 to 120°C, preferably 40 to 110°C, more preferably 50 to 100°C, and most preferably 60 to 90°C. Note that in the present application, the glass transition temperature can be measured using a differential scanning calorimeter.

The (meth)acrylic resin (B1) may be a (meth)acrylic resin that does not have a carboxyl group or a salt thereof.

The proportion of the (meth)acrylic resin (B1) is, for example, 1 to 50 parts by mass, preferably 3 to 40 parts by mass, based on 100 parts by mass of the silver-containing metal of the composite nanoparticles (A), in terms of solid content. parts, more preferably 5 to 30 parts by weight, more preferably 10 to 25 parts by weight, most preferably 15 to 20 parts by weight. If the proportion of the (meth)acrylic resin is too small, there is a risk that the adhesion and scratch resistance will be reduced, and if it is too large, there is a possibility that the silver luster will be reduced.

(B2) Polyvinyl acetal resin The polyvinyl acetal resin (B2) is obtained by reacting polyvinyl alcohol obtained by saponifying polyvinyl acetate with an aldehyde (especially n-butyraldehyde) (acetalization reaction). In the acetalization reaction, polyvinyl alcohol cannot be completely acetalized (especially butyralized), so hydroxyl groups remain, and a small amount of acetyl groups remain during saponification, so polyvinyl acetal resins ( B2) has an acetal group, a hydroxyl group, and an acetyl group in the structural unit.

That is, the polyvinyl acetal resin (B2) has, as structural units, a vinyl acetal unit represented by the following formula (1), a vinyl alcohol unit represented by the following formula (2), and a vinyl alcohol unit represented by the following formula (3). Contains vinyl ester units.

（式中、Ｒ^１は水素原子または炭化水素基である）。

(wherein R ¹ is a hydrogen atom or a hydrocarbon group).

In the formula (1), the hydrocarbon group represented by R ¹ includes an alkyl group, a cycloalkyl group, and an aryl group. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a t-butyl group, a hexyl group, a 2-ethylbutyl group, an octyl group, a 2-ethylhexyl group, and a nonyl group. Examples include linear or branched C _1-10 alkyl groups. Examples of the cycloalkyl group include C _5-10 cycloalkyl groups such as hexyl group. Examples of the aryl group include C _6-10 aryl groups such as phenyl group. As R ¹ , these hydrocarbon groups and hydrogen atoms can be used alone or in combination of two or more.

Among these, R ¹ is preferably a hydrogen atom or an alkyl group, more preferably a linear or branched C _1-5 alkyl group, more preferably a linear C _2-4 alkyl group, and a propyl group is more preferable. Most preferred. That is, as the polyvinyl acetal resin, polyvinyl formal resin and polyvinyl butyral resin (butyral resin) are preferable, and polyvinyl butyral resin is particularly preferable.

In addition to the structural units represented by formulas (1) to (3), the polyvinyl acetal resin (B2) may further contain other structural units. Other structural units may be units derived from copolymerizable monomers having radically polymerizable groups.

Examples of copolymerizable monomers include C _3-8 alkanoic acid-vinyl esters such as vinyl propionate, vinyl butyrate, vinyl pivalate, and vinyl caproate; methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i- C _1-6 alkyl-vinyl ethers such as propyl vinyl ether and n-butyl vinyl ether; α-C _2-6 olefins such as ethylene, propylene, 1-butene, isobutene, and 1-hexene; (meth)acrylic acid and its salts; (meth)acrylic acid C _1-6 alkyl esters such as methyl meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate; (meth)acrylamide; unsaturated sulfones such as ethylenesulfonic acid and allylsulfonic acid Examples include acids. These copolymerizable monomers can be used alone or in combination of two or more.

Further, the polyvinyl acetal resin (B2) may be a polyvinyl acetal resin modified or modified by a conventional method.

The proportion of the units represented by the formula (1) in the polyvinyl acetal resin (B2) (degree of acetalization) is about 5 to 95 mol% (for example, 10 to 90 mol%), and depending on the use, for example It may be 20 to 90 mol%, preferably 30 to 85 mol%, and 50 mol% or more (for example, 50 to 90 mol%), preferably 60 mol% or more (for example, 60 to 85 mol%), more preferably may be 70 mol% or more (for example, 70 to 80 mol%). Further, the degree of acetalization may be, for example, 9 to 98% by mass, preferably 25 to 95% by mass, more preferably 35 to 90% by mass, and 55% by mass or more (for example, 55 to 95% by mass), preferably is 65% by mass or more (for example, 65 to 90% by mass), more preferably 70% by mass or more (for example, 70 to 80% by mass). If the degree of acetalization is too small, there is a risk that the silver luster will be reduced, and if the degree of acetalization is too high, there is a risk that it will be difficult to prepare a polyvinyl acetal resin.

The proportion of the unit represented by the formula (2) (unit having a hydroxyl group) in the polyvinyl acetal resin (B2) may be 10 to 50 mol% (for example, 15 to 40 mol%), preferably 20 to 50 mol%. ~35 mol%, more preferably 23~27 mol%. Further, the proportion of the units represented by the formula (2) in the polyvinyl acetal resin (B2) may be 5 to 40% by mass (for example, 12 to 30% by mass), preferably 15 to 25% by mass. , more preferably 18 to 23% by mass. If the proportion of the units represented by formula (2) is too small, there is a risk that the silver luster will decrease when polyvinyl acetal resin is used alone as a resin component, and conversely, if the proportion is too large, the same will happen. Polyvinyl acetal resin (B2) has a high affinity for silver-containing metal nanoparticles (particularly composite nanoparticles (A)) and is easy to cure with a curing agent depending on the application, so polyvinyl acetal resin (B2) contains a unit having a hydroxyl group. It is preferable to include.

The proportion of the unit represented by the formula (3) (unit having an acetyl group) in the polyvinyl acetal resin (B2) is, for example, 15 mol% or less, preferably 10 mol% or less, more preferably 5 mol% or less. It is. Further, the proportion of the units represented by the formula (3) in the polyvinyl acetal resin (B2) is, for example, 20% by mass or less, preferably 10% by mass or less, and more preferably 5% by mass or less. If the proportion of the units represented by formula (3) is too large, there is a risk that silver luster may be reduced.

The total proportion of the structural units represented by formulas (1) to (3) in the polyvinyl acetal resin (B2) is, for example, 80 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more. More preferably, it is 100 mol%.

The proportion derived from the copolymerizable monomer in the polyvinyl acetal resin (B2) is, for example, 20 mol% or less, preferably 10 mol% or less, and more preferably 5 mol% or less.

In the present application, the degree of acetalization and the proportion of each unit of the polyvinyl acetal resin (B2) can be measured using a conventional method, for example, a titration method, an IR method, an NMR method, etc. In the case of a butyral resin, it can be measured by a method based on JIS K 6728 "Polyvinyl butyral test method".

The weight average molecular weight of the polyvinyl acetal resin (B2) (especially butyral resin) is, for example, 5,000 to 100,000, preferably 7,000 to 70,000, more preferably 10,000 to 40,000, More preferably 12,000 to 20,000. If the molecular weight is too small, there is a risk that the mechanical properties of the silver glossy film will deteriorate, and if the molecular weight is too high, there is a risk that the film formability will deteriorate.

In addition, in this application, the weight average molecular weight of the polyvinyl acetal resin (B2) is based on the molecular weight of standard polystyrene from a chromatogram measured by gel permeation chromatography (GPC) according to the method described in JIS K 0124-2011. This is the value calculated using

The glass transition temperature of the polyvinyl acetal resin (B2) (especially butyral resin) can be selected from a range of about 50 to 130°C, for example 60 to 125°C, preferably 70 to 120°C, more preferably 80 to 115°C. , more preferably 90 to 115°C. If the glass transition temperature is too low, there is a risk that the mechanical properties of the silver luster film will deteriorate, and if it is too high, there is a risk that film formability will deteriorate.

In this application, the glass transition temperature of the polyvinyl acetal resin (B2) can be measured using a differential scanning calorimeter (DSC).

The 10% by mass solution viscosity (solvent: toluene/ethanol (mass ratio) = 50/50) of polyvinyl acetal resin (B2) (especially butyral resin) is of rotational viscosity type (BM type) at a temperature of 20°C. When measured, it can be selected from a range of about 2 to 20,000 mPa・s (especially 10 to 10,000 mPa・s), and depending on the application, for example, 5 to 1,000 mPa・s (for example, 10 to 500 mPa・s), Preferably, the pressure may be 20 to 400 mPa·s (for example, 25 to 300 mPa·s), more preferably 50 to 250 mPa·s (for example, 70 to 200 mPa·s), and, for example, 3 to 150 mPa·s (for example, 5 to 100 mPa·s).・s), preferably 10 to 50 mPa·s (especially 10 to 30 mPa·s). If the viscosity is too low, there is a risk that the mechanical properties of the silver glossy film will deteriorate, and if the viscosity is too high, there is a possibility that the film formability will deteriorate.

(B3) Polyester Resin Polyester resin (B3) is a polymer synthesized by dehydration condensation of polycarboxylic acid and polyol as monomers to form ester bonds. The polyester resin (B3) (or polyester resin) in the present disclosure includes, but is not particularly limited to, polyester polyols (B3a), alkyd resins (B3b), and the like.

Polyester polyols (B3a) are polymers having ester bonds in their molecular chains, and have two or more hydroxyl groups in one molecule.

Polyester polyols (B3a) include, for example, polyester polyols obtained by esterifying a low molecular weight polyol and polycarboxylic acid; polyester polyols obtained by ring-opening polymerization reaction of a cyclic ester compound; polyether polyols, polyester polyols Polyester polyols obtained by reacting (adding) a cyclic ester compound with one or more selected from the group consisting of polycarbonate polyols and/or low molecular weight polyols as an initiator; copolymerized polyester polyols of these, and the like.

As the low molecular weight polyol as a raw material for the polyester polyols (B3a), polyols having a molecular weight of about 50 to 300 can be used, such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentane. Diol, 1,6-hexanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, trimethyl C2-6 aliphatic polyols (diols or trifunctional or higher functional polyols) such as propane and glycerin; alicyclic structure-containing polyols such as 1,4-cyclohexanediol and cyclohexanedimethanol; bisphenol A and bisphenol F, etc. bisphenol compounds and their alkylene oxide adducts, aromatic polyols such as p-hydroxyphenethyl alcohol, and the like.

These low molecular weight polyols can be used alone or in combination of two or more.

The polycarboxylic acid as a raw material for the polyester polyols (B3a) is not particularly limited, and includes, for example, aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and dimer acid; Alicyclic dicarboxylic acids such as 4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, and 1,2-cyclohexanedicarboxylic anhydride; terephthalic acid, isophthalic acid, orthophthalic acid, naphthalene dicarboxylic acid Aromatic dicarboxylic acids such as biphenyldicarboxylic acid and diphenic acid; Oxypolycarboxylic acids such as 4,4-bis(p-hydroxyphenyl)valeric acid and 5-hydroxyisophthalic acid; Sulfoterephthalic acid and 5-sulfoisophthalic acid , 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, 5(4-sulfophenoxy)isophthalic acid, and other aromatic dicarboxylic acids having a sulfonic acid group or a sulfonic acid group (metal salt, ammonium salt, etc.) Examples include.

These polycarboxylic acids can be used alone or in combination of two or more.

Examples of the cyclic ester compound as a raw material for the polyester polyols (B3a) include C _4-8 lactones such as β-butyrolactone, δ-valerolactone, and ε-caprolactone. These cyclic ester compounds can be used alone or in combination of two or more. Among these, ε-caprolactone is commonly used.

Examples of the polyester polyol (raw material to which a cyclic ester compound is added) as a raw material for the polyester polyols (B3a) include polyester polyols obtained by esterifying a low molecular weight polyol and a polycarboxylic acid.

Examples of the polyether polyol as a raw material for the polyester polyols (B3a) include, for example, a single or copolymer of alkylene oxide [poly(C _{2 -4} alkylene glycol)], bisphenol A or an alkylene oxide adduct of hydrogenated bisphenol A, and the like.

Examples of the polycarbonate polyol as a raw material for the polyester polyols (B3a) include the above-mentioned low molecular weight diol, dialkyl carbonate (such as di-C _1-4 alkyl carbonate such as dimethyl carbonate) or diaryl carbonate (di-C ₆ such as diphenyl carbonate). _-12 aryl carbonate, etc.).

Polyester polyols, polyether polyols, and polycarbonate polyols as raw materials for polyester polyols (B3a) can be used alone or in combination of two or more.

Polyester polyols (B3a) may contain oxycarboxylic acids such as p-hydroxyphenylpropionic acid, p-hydroxybenzoic acid, p-hydroxyphenylacetic acid, and 6-hydroxy-2-naphthoic acid as copolymerization components, if necessary. may further include.

The polyester polyols (B3a) may contain a trifunctional or higher functional component as a copolymerization component in the polycarboxylic acid component and/or polyol component, if necessary, for the purpose of introducing a branched skeleton.

The hydroxyl value of the polyester polyols (B3a) is, for example, 5 to 500 mgKOH/g, preferably 10 to 300 mgKOH/g, more preferably 20 to 200 mgKOH/g, more preferably 30 to 150 mgKOH/g, most preferably 50 to It is 100mgKOH/g. If the hydroxyl value is too low, there is a risk that the silver luster and the mechanical properties of the silver luster film will be reduced, whereas if it is too high, there is a risk that the silver luster will be reduced.

In the present application, the hydroxyl value of the polyester polyol (B3a) can be measured in accordance with JIS K1557-1.

A carboxyl group may be introduced into the polyester polyol (B3a). The acid value of the polyester polyol is preferably 0.1 to 10 mgKOH/g, more preferably 0.2 to 5 mgKOH/g (for example, 0.3 to 1 mgKOH/g).

In addition, in this application, the acid value of polyester polyol (B3a) can be calculated by titration according to the potassium hydroxide method.

Examples of the method for introducing a carboxyl group include a method of introducing a carboxylic acid into a polyester polyol by acid addition after polymerization. If a monocarboxylic acid, dicarboxylic acid, or polycarboxylic acid compound with trifunctional or higher functionality is used for acid addition, the molecular weight may decrease due to transesterification, so it is recommended to use a compound having at least one carboxylic acid anhydride group. preferable. Examples of carboxylic anhydrides include succinic anhydride, maleic anhydride, orthophthalic acid, 2,5-norbornenedicarboxylic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride (PMDA), and oxydiphthalic dianhydride. (ODPA), 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 3,3',4,4'-diphenyltetracarboxylic dianhydride (BPDA), 3,3 ',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA), 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), 2,2'-bis[(dicarboxyphenoxy ) phenyl]propane dianhydride (BSAA) and the like.

The weight average molecular weight of the polyester polyols (B3a) is, for example, 600 to 20,000, preferably 1,000 to 10,000, more preferably 1,300 to 5,000, and more preferably 1,500 to 3,000. be. If the molecular weight is too small, there is a risk that the mechanical properties of the silver glossy film will deteriorate, and if the molecular weight is too high, there is a risk that the film formability will deteriorate.

In this application, the weight average molecular weight of the polyester polyol (B3a) is a value calculated based on the molecular weight of standard polystyrene from a chromatogram measured by gel permeation chromatography (GPC).

(B3b) Alkyd resin The alkyd resin (B3b) is a commonly used alkyd resin used in the paint field, etc., and includes, for example, short oil alkyd resin, long oil alkyd resin, modified alkyd resin, isocyanate-curing alkyd resin, and epoxy ester. It may also be a resin (epoxy-modified alkyd resin), alkyd polyol, oil-free alkyd resin, or the like.

The specific alkyd resin (B3b) is, for example, a synthetic resin defined in JIS K 5500 "Paint Terms", that is, a synthetic resin obtained by condensation polymerization of a polycarboxylic acid and an oil component with a polyol (polyhydric alcohol). It may also be a resin.

Examples of polycarboxylic acids include aromatic dicarboxylic acids such as phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, 2,6-naphthalene dicarboxylic acid, and 5-sodium sulfoisophthalic acid; tetrahydrophthalic acid, and tetrahydrophthalic anhydride. , hexahydrophthalic acid, hexahydrophthalic anhydride, alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid; succinic acid, succinic anhydride, alkenylsuccinic acid, alkenylsuccinic anhydride, fumaric acid, maleic acid, maleic anhydride aliphatic dicarboxylic acids such as itaconic acid, adipic acid, sebacic acid, azelaic acid, himic acid, and himic anhydride; trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, methylcyclohexentricarboxylic acid, Trifunctional or higher functional polycarboxylic acids such as methyl cyclohexene tricarboxylic anhydride and benzophenone tetracarboxylic acid are included.

These polycarboxylic acids can be used alone or in combination of two or more. Among these, aromatic dicarboxylic acids such as isophthalic acid and terephthalic acid are commonly used.

The oil component (fat component) includes fatty oil (oil or fat) and/or fatty acid.

Examples of fatty oils include cottonseed oil, linseed oil, tung oil, castor oil, dehydrated castor oil, safflower oil, soybean oil, rice oil, corn oil, sesame oil, sunflower oil, rice sugar oil, flaxseed oil, rapeseed oil, Vegetable oils such as peanut oil, coconut oil, palm oil, kapok oil, tonsil oil, olive oil, tall oil, and scallion oil; Animal oils such as beef tallow, pork tallow, mutton tallow, goat tallow, horse tallow, chicken tallow, and turkey tallow ; Fish oils such as herring oil, flounder oil, cod oil, sole oil, halibut oil, carp oil, trout oil, and catfish oil; and hydrogenated oils thereof. These fats and oils can be used alone or in combination of two or more.

Fatty acids include linear or branched saturated C _8-24 fatty acids such as caprylic acid, capric acid, pelargonic acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, behenic acid; myristoleic acid , linear or branched chain unsaturated _C8-24 fatty acids such as palmitoleic acid, petroselic acid, oleic acid, vaccenic acid, linoleic acid, linolenic acid, eleostearic acid, gatolenic acid, arachidonic acid, erucic acid, etc. . These fatty acids may have substituents such as hydroxyl groups. Examples of fatty acids having hydroxyl groups include ricinoleic acid, sabinic acid, and dioxystearic acid, which are the main components of castor oil. The fatty acid may be a fatty acid obtained from the above-mentioned fatty oil by saponification or the like, such as a high diene fatty acid obtained from dehydrated castor oil, a fatty acid obtained from linseed oil, tung oil, dehydrated castor oil, soybean oil, safflower oil, etc. (For example, linseed oil fatty acid, tung oil fatty acid, dehydrated castor oil fatty acid, soybean oil fatty acid, safflower oil fatty acid, etc.). These fatty acids can be used alone or in combination of two or more.

Among these oil components, vegetable oils such as linseed oil, tung oil, dehydrated castor oil, soybean oil, and safflower oil; fatty acids derived from these vegetable oils; saturated C _10-22 fatty acids such as stearic acid; oleic acid, linoleic acid, and linolenic acid. Unsaturated C _10-22 fatty acids such as stearic acid, eleostearic acid or ricinoleic acid are preferred.

Examples of polyols include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 2-methyl -1,8-octanediol, neopentyl glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, tetramethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, Diols such as 2-butyl-2-ethyl-1,3-propanediol; triols such as glycerin, trimethylolpropane, trimethylolethane; pentaerythritol, diglycerin, ditrimethylolpropane, ditrimethylolethane, tris(2-hydroxy Examples include polyols having four or more functional functions such as (ethyl) isocyanurate and dipentaerythritol; and polyhydric alcohols conventionally used in alkyd resins.

These polyols can be used alone or in combination of two or more. Among these, aliphatic polyols such as glycerin, trimethylolpropane, pentaerythritol, and dipentaerythritol are commonly used.

In addition to the oil component and the polyol, the alkyd resin (B3b) may further contain a monocarboxylic acid such as benzoic acid, pt-butylbenzoic acid, abietic acid, and hydrogenated abietic acid.

These alkyd resins can be used alone or in combination of two or more. Among these, alkyd resins having hydroxyl groups are preferable because they have a high affinity for silver-containing metal nanoparticles (particularly composite nanoparticles (A)) and are easily cured with a curing agent depending on the application. Particularly preferred are alkyd resins having a plurality of hydroxyl groups, such as type alkyd resins. Note that the position of the hydroxyl group is not particularly limited, and it may be located on the main chain, on the side chain, or on the main chain and the side chain.

The hydroxyl value of the alkyd resin (B3b) is, for example, 5 to 500 mgKOH/g, preferably 10 to 300 mgKOH/g, more preferably 20 to 200 mgKOH/g, and more preferably 50 to 150 mgKOH/g. If the hydroxyl value is too low, there is a risk that the silver luster and the mechanical properties of the silver luster film will be reduced, whereas if it is too high, there is a risk that the silver luster will be reduced.

In addition, in this application, the hydroxyl value of alkyd resin (B3b) can be measured based on ISO 4629 (2).

The acid value of the alkyd resin (B3b) is, for example, 0.5 to 30 mgKOH/g, preferably 1 to 20 mgKOH/g, more preferably 2 to 15 mgKOH/g, and more preferably 3 to 8 mgKOH/g. If the acid value is too low, there is a risk that the silver luster will be reduced, and if the acid value is too high, there is a possibility that the silver luster and the mechanical properties of the silver luster film will be deteriorated.

In the present application, the acid value of the alkyd resin (B3b) can be measured in accordance with JIS K 5601-1-2.

The weight average molecular weight of the alkyd resin (B3b) is, for example, 500 to 30,000, preferably 1,000 to 20,000, and more preferably 2,000 to 10,000. If the molecular weight is too small, there is a risk that the mechanical properties of the silver glossy film will deteriorate, and if the molecular weight is too high, there is a risk that the film formability will deteriorate.

In this application, the weight average molecular weight of the alkyd resin (B3b) is a value calculated from a chromatogram measured by gel permeation chromatography (GPC) based on the molecular weight of standard polystyrene.

Among the polyester resins (B3), polyesters having hydroxyl groups are preferred because they have a high affinity for silver-containing metal nanoparticles (especially composite nanoparticles (A)) and are easily cured with a curing agent depending on the application. type resins are preferred, and polyester polyols (B3a) are particularly preferred.

Among the non-silicone resins (B), those selected from the group consisting of (meth)acrylic resins (B1), polyvinyl acetal resins (B2) and polyester polyols (B3a) are selected from the viewpoint of improving silver luster. At least one type of resin is preferred, and (meth)acrylic resin (B1) is most preferred.

(C) Silicone Resin The ink composition of the present invention further contains a silicone resin (C) in addition to the composite nanoparticles (A) and non-silicone resin (B). The silicone resin (C) has a lower affinity for the silver-containing metal nanoparticles (especially the composite nanoparticles (A)) than the non-silicone resin (B). In this combination, a phase-separated structure can be formed in the membrane.

The silicone resin (C) is not particularly limited, and may be a silicone resin or a silicone oligomer. Among these, silicone resins are preferred because they can improve adhesion and scratch resistance.

The silicone resin may be a thermoplastic resin, a curable resin (uncrosslinked resin), or a cured resin (crosslinked resin) having a polyorganosiloxane skeleton. The polyorganosiloxane skeleton is a linear, branched or network compound having Si-O bonds (siloxane bonds), and has the formula: R ² _a SiO _(4-a)/2 (in the formula, R ² represents a substituent, and the coefficient a is a number from 0 to 3). Silicone resins include monofunctional M units (generally represented by R 2 3 SiO 1/2), which are each unit represented by the above formula, and difunctional D units (generally represented by R ² ₃ SiO _1/2 ). unit represented by R ² ₂ SiO _2/2 ), trifunctional T unit (generally represented by R ² SiO _3/2 ), tetrafunctional Q unit (generally represented by SiO _4/ Among the units represented by ₂ ), polyorganosiloxanes containing T units as main units are usually used.

In the above formula, the substituent R ² is, for example, a C _1-10 alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a 3-chloropropyl group, a 3,3,3-trifluoropropyl group, etc. Halogenated C _1-10 alkyl group, C _2-10 alkenyl group such as vinyl group, allyl group, butenyl group, C _6-20 aryl group such as phenyl group, tolyl group, naphthyl group, cyclopentyl group, cyclohexyl group, etc. Examples include C _3-10 cycloalkyl groups, C _6-12 aryl-C _1-4 alkyl groups such as benzyl groups, and phenethyl groups. These substituents can be used alone or in combination of two or more.

Among these, R ² is preferably a C _1-4 alkyl group such as a methyl group or a propyl group, a C _6-10 aryl group such as a phenyl group or a naphthyl group, a C _1-3 alkyl group, or a C _6-8 alkyl group. An aryl group is more preferred, and a methyl group and a phenyl group are most preferred. Furthermore, as for R ² , it is preferable to use two or more types in combination rather than using it alone from the viewpoint of improving compatibility with the ( _meth )acrylic resin _{. A -10} aryl group is more preferred, a combination of a C _1-3 alkyl group and a C _6-8 aryl group is more preferred, and a combination of a methyl group and a phenyl group is most preferred.

When combining a C _1-4 alkyl group and a C _6-10 aryl group, the molar ratio of the two is selected from a range of approximately C _1-4 alkyl group/C _6-10 aryl group = 30/1 to 1/30. For example, 20/1 to 1/10, preferably 10/1 to 1/5, more preferably 8/1 to 1/1, more preferably 5/1 to 1.5/1, most preferably 3/1. It is 1 to 2/1.

The silicone resin may be a straight silicone resin (unmodified silicone resin) or a modified silicone resin. Examples of the modified silicone resin include silicone resins modified with other resins such as alkyd resins, phenol resins, urea resins, melamine resins, and epoxy resins.

Specifically preferred silicone resins include C _1-4 alkyl silicone resins in which the substituent R ² is a C _1-4 alkyl group such as a methyl group (for example, C _1-3 alkyl resins such as methyl silicone resins). silicone resin, etc.), C _6-10 aryl silicone resin in which substituent R ² is a C _6-10 aryl group such as phenyl group (for example, C _6-8 aryl silicone resin such as phenyl silicone resin), substituted C _1-4 alkyl C _6-10 aryl silicone resin in which the group R ² is a combination of a C _1-4 alkyl group and a C _6-10 aryl group (for example, methylphenyl silicone resin, propylphenyl silicone resin, etc.) C _1-3 alkyl C _6-8 aryl silicone resin, etc.). These silicone resins can be used alone or in combination of two or more. From the viewpoint of improving adhesion and scratch resistance, alkylaryl silicone resins such as C _1-4 alkyl C _6-10 aryl silicone resins are preferred, and C _1-2 alkyl C _6- such as methylphenyl silicone resins are preferred. Particularly preferred are _8- aryl silicone resins.

The mass ratio of the non-silicone resin (B) and the silicone resin (C) can be selected from the range of former/latter = about 97/3 to 3/97, for example 95/5 to 5/95, preferably 90 /10 to 10/90 (for example, 80/20 to 30/70), more preferably 75/25 to 40/60, more preferably 70/30 to 40/60 (especially 65/35 to 55/45) . If the proportion of the non-silicone resin (B) is too small, there is a risk that the silver luster and adhesion will decrease, and if the proportion is too large, the same may occur.

The total proportion of the non-silicone resin (B) and the silicone resin (C) is 1 to 500 parts by mass (for example, 5 parts by mass) based on 100 parts by mass of the silver-containing metal of the composite nanoparticles (A), in terms of solid content. -300 parts by weight), for example, 10 to 300 parts by weight (for example, 10 to 250 parts by weight), preferably 10 to 200 parts by weight (for example, 10 to 150 parts by weight), more preferably 10 to 100 parts by weight. parts (for example, 10 to 50 parts by weight), more preferably 20 to 50 parts by weight (especially 25 to 35 parts by weight). If the total ratio is too small, there is a risk that the adhesion and scratch resistance will be reduced, and if it is too large, there is a risk that the silver luster will be reduced.

(D) Solvent The ink composition of the present invention further contains a solvent (D) in addition to the composite nanoparticles (A), non-silicone resin (B), and silicone resin (C). By blending the solvent (D) with the non-silicone resin (B) and the silicone resin (C), phase separation due to spinodal decomposition can be promoted, and film-forming properties can also be improved.

Preferably, the solvent (D) contains a polar organic solvent. Examples of polar organic solvents include alcohols (C _1-4 alkanols such as methanol, ethanol, propanol, and isopropanol, 3-methoxy-3-methyl-1-butanol, etc.), polyhydric alcohols (ethylene glycol, propylene glycol, etc.), and polyhydric alcohols (ethylene glycol, propylene glycol, etc.). alkanediols such as glycerin, alkanetriols such as trimethylolpropane, alkanetetraols such as pentaerythritol), amides (acylamides such as formamide and acetamide, N-methylformamide, N-methylacetamide, N,N- dimethylformamide, mono- or di-C _1-4 acylamides such as N,N-dimethylacetamide, etc.), pyrrolidones (2-pyrrolidone, 3-pyrrolidone, N-methyl-2-pyrrolidone, N-methyl-3-pyrrolidone, etc.) ), ketones (acetone, diacetone alcohol, methyl ethyl ketone, isophorone, etc.), ethers (dioxane, tetrahydrofuran, etc.), organic carboxylic acids (acetic acid, etc.), esters (methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, acetic acid) acetate esters such as amyl), alkylene glycol monoalkyl ethers (methyl cellosolve, ethyl cellosolve, propylene glycol methyl ether, C _2-6 alkylene glycol mono C _1-4 alkyl such as 3-methoxy-3-methyl-1-butanol) ethers, etc.), dialkylene glycol monoalkyl ethers (di-C _2-6 alkylene glycol mono-C _1-4 alkyl ethers such as methyl carbitol, ethyl carbitol, propyl carbitol, butyl carbitol, etc.), cellosolve acetates (ethyl Examples include C _1-4 alkyl cellosolve acetates such as cellosolve acetate), carbitol acetates (C _1-4 alkyl carbitol acetates such as methyl carbitol acetate and butyl carbitol acetate), and dimethyl sulfoxide. These polar organic solvents can be used alone or in combination of two or more.

The proportion of the polar organic solvent in the solvent may be 50% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, and 100% by mass. Good too.

The solvent (D) may further contain a nonpolar solvent in addition to the polar solvent. Examples of the nonpolar solvent include aliphatic hydrocarbons such as hexane, octane, and decane, and alicyclic hydrocarbons such as cyclohexane and tetralin. The proportion of the nonpolar organic solvent may be 50 parts by mass or less (for example, about 0.1 to 50 parts by mass), preferably 30 parts by mass or less, and more preferably 10 parts by mass based on 100 parts by mass of the polar organic solvent. below.

Among these solvents, it is preferable to contain one or more selected from alcohols, esters, alkylene glycol monoalkyl ethers and dialkylene glycol monoalkyl ethers, and aliphatic carboxylic acid C _1-6 alkyl esters, C ₂ More preferably, one or more selected from _-6 alkylene glycol mono C _1-3 alkyl ether and di-C _2-6 alkylene glycol mono C _1-3 alkyl ether, such as acetic acid C _1-5 alkyl ester, C _2-3 alkylene One or more selected from glycol mono C _1-2 alkyl ether and di-C _4-6 alkylene glycol mono C _1-2 alkyl ether are most preferred. The dialkylene glycol monoalkyl ether may be a polar solvent derived from a dispersion medium for dispersing colloidal silver particles as a raw material.

The proportion of the solvent (D) is, for example, 50 to 500 parts by mass, preferably 80 to 400 parts by mass, and more preferably 100 to 300 parts by mass, relative to 100 parts by mass of the silver-containing metal of the composite nanoparticles (A). , more preferably 120 to 250 parts by weight, most preferably 150 to 200 parts by weight. If the proportion of the solvent is too small, it will be difficult to form a phase-separated structure and there is a risk that film-forming properties will be reduced, and if it is too large, there is a possibility that productivity and film-forming properties will be reduced.

(E) Curing agent In addition to the composite nanoparticles (A), non-silicone resin (B), silicone resin (C) and solvent (D), the ink composition of the present invention contains a curing agent (E). may further include. Examples of the curing agent (E) include conventional curing agents, such as isocyanate curing agents, amine curing agents, acid anhydride curing agents, and imidazole curing agents. Among these, isocyanate-based curing agents are preferred, and polyisocyanates are particularly preferred. Isocyanate curing agents such as polyisocyanate are particularly effective when the non-silicone resin has a functional group (particularly a hydroxyl group).

Examples of the polyisocyanate include aliphatic polyisocyanates [diisocyanates such as propylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMDI), and lysine diisocyanate (LDI); , 11-undecane triisocyanate methyl octane, 1,3,6-hexamethylene triisocyanate and other tri- or polyisocyanates], alicyclic polyisocyanates [cyclohexane 1,4-diisocyanate, isophorone diisocyanate (IPDI), hydrogenated xylylene di isocyanates, diisocyanates such as hydrogenated bis(isocyanatophenyl)methane; tri- or polyisocyanates such as bicycloheptane triisocyanate], aromatic polyisocyanates [phenylene diisocyanate, tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), Diisocyanates such as tetramethylxylylene diisocyanate (TMXDI), naphthalene diisocyanate (NDI), bis(isocyanatophenyl)methane (MDI), toridine diisocyanate (TODI), 1,3-bis(isocyanatophenyl)propane; isocyanate] and the like.

Polyisocyanates include derivatives such as multimers (dimers, trimers, tetramers, etc.), adducts, modified products (biuret modified products, allophanate modified products, urea modified products, etc.), and derivatives containing multiple isocyanate groups. It may also be a urethane oligomer having Modified products or derivatives of polyisocyanates include, for example, adducts of polyisocyanates (aliphatic polyisocyanates such as hexamethylene diisocyanate, etc.) and polyhydric alcohols (trimethylolpropane, pentaerythritol, etc.), and biuret products of the polyisocyanates. , a multimer of the polyisocyanate (for example, aliphatic polyisocyanate) (for example, a polyisocyanate having an isocyanurate ring such as a trimer of hexamethylene diisocyanate), and the like.

These polyisocyanates can be used alone or in combination of two or more. Among these polyisocyanates, aliphatic polyisocyanates or derivatives thereof (for example, HDI or its trimer, etc.), aromatic polyisocyanates (TDI, MDI, etc.), and the like are commonly used.

The proportion of the curing agent (E) is, for example, 10 to 200 parts by weight, preferably 20 to 150 parts by weight, and more preferably 25 to 100 parts by weight, based on 100 parts by weight of the non-silicone resin (B).

(F) Other metal nanoparticles In addition to the composite nanoparticles (A), non-silicone resin (B), silicone resin (C) and solvent (D), the ink composition of the present invention contains other metal nanoparticles. It may further contain metal nanoparticles (F). Examples of other metal nanoparticles (F) include metals from group 8 of the periodic table (iron, nickel, cobalt, ruthenium, rhodium, palladium, rhenium, iridium, platinum, etc.), metals from group 1B of the periodic table (copper, gold, etc.). ), Group 3B metals of the periodic table (aluminum, gallium, indium, etc.), metals of Group 4B of the periodic table (germanium, tin, lead, etc.), and the like. Note that the metal (metal atom) is often a metal that has a high degree of coordination with the protective colloid, such as a metal from group 8 of the periodic table or a metal from group 1B of the periodic table. The proportion of other metal nanoparticles (F) is 100 parts by mass or less, preferably 50 parts by mass or less, more preferably 10 parts by mass, based on 100 parts by mass of the silver-containing metal of the composite nanoparticles (A). It is as follows.

(G) Other components In the ink composition of the present invention, other components (G) may include conventional additives such as plasticizers (or film-forming aids), gloss Additives, metal corrosion inhibitors (rust inhibitors), stabilizers (antioxidants, ultraviolet absorbers, light stabilizers, etc.), surfactants (anionic surfactants, cationic surfactants, nonionic surfactants) agents, amphoteric surfactants, in particular anionic and/or nonionic surfactants), dispersion stabilizers, thickeners or viscosity modifiers, humectants, thixotropic agents, leveling agents, penetrating agents. , antifoaming agents, pH adjusting agents, chelating agents, surface tension adjusting agents, coloring agents (such as dyes and pigments), hue improvers, dye fixing agents, bactericidal agents, antifungal agents, preservatives, oxygen absorbers, etc. It's okay to stay. Note that the surfactant may be an acetylene glycol surfactant, a polysiloxane surfactant, a fluorine surfactant, or the like. These additives can be used alone or in combination of two or more. The proportion of the other component (G) is 50 parts by mass or less, preferably 30 parts by mass or less, more preferably 10 parts by mass or less, based on 100 parts by mass of the silver-containing metal of the composite nanoparticles (A). be.

[Method for preparing ink composition]
The ink composition of the present invention can be prepared by mixing the composite nanoparticles (A), non-silicone resin (B), silicone resin (C) and solvent (D) in a conventional manner. As a mixing method, a conventional stirring device may be used, for example, a stirring defoaming device may be used. The composite nanoparticles (A) are in the form of a dispersion in dialkylene glycol monoalkyl ether, and are mixed with a non-silicone resin (B), a silicone resin (C), and an alkylene glycol monoalkyl ether. Good too.

[Method for manufacturing silver gloss film]
The silver gloss film is produced by applying the ink composition onto the object to be decorated (substrate) to form a coating film, and drying the coating film to form phase separation due to spinodal decomposition. It is obtained through a phase separation process to form .

In the coating process, the type of base material is not particularly limited, and resin substrates, metal substrates, glass substrates, ceramic substrates, paper, etc. can be used depending on the purpose.

The application method is not particularly limited and may include any conventional coating method, such as flow coating method, dispenser coating method, spin coating method, spray coating method, screen printing method, flexographic printing method, casting method, bar coating method, curtain coating method. method, roll coating method, gravure coating method, dipping method, slit method, photolithography method, inkjet method, offset printing method, etc. can be used.

The average thickness (dry thickness) of the coating film is, for example, 0.05 to 100 μm, preferably 0.1 to 30 μm, more preferably 0.5 to 10 μm, and even more preferably 1 to 5 μm.

In addition, in the present invention, it is possible to achieve both silver luster, adhesion, and scratch resistance without forming an undercoat layer or a topcoat layer, but depending on the application, an undercoat layer and/or a topcoat layer may also be used in combination. good.

In the phase separation process, by drying the coating film, as the solvent evaporates, spinodal decomposition occurs, forming a phase formed of non-silicone resin containing a large amount of silver-containing metal and a phase formed of non-silicone resin containing a small amount of silver-containing metal. It undergoes phase separation from the phase formed by the resin.

As a method for drying the coating film, a method of heating and drying is preferable, and a method of heating and drying in two stages combining a preliminary heat treatment and a main heat treatment is preferable since it is easy to form a phase-separated structure. .

In the preheating treatment, the preheating temperature is, for example, 40 to 80°C, preferably 45 to 70°C, more preferably 45 to 60°C, and more preferably 45 to 55°C. The preheating time is, for example, 1 to 100 minutes, preferably 3 to 60 minutes, and more preferably 5 to 30 minutes.

In the main heat treatment, the main heating temperature is, for example, 60 to 150°C, preferably 65 to 120°C, more preferably 70 to 90°C, and more preferably 75 to 85°C. The main heating time is, for example, 30 to 240 minutes, preferably 80 to 180 minutes, and more preferably 100 to 150 minutes.

[Structure of silver gloss film]
The silver luster film obtained by the above method is formed on a base material (object to be decorated), is laminated on the base material, is laminated on the base material, and contains silver. An interface layer formed of composite nanoparticles (A) of a metal and a protective colloid, and a composite nanoparticle (A) of a metal containing silver and a protective colloid laminated on this interface layer, and a non-silicone system. A first phase containing a resin (B), a composite nanoparticle (A) of a metal containing silver and a protective colloid, and a silicone resin (C), with a content ratio of a metal containing silver (silver-containing metal). An intermediate layer phase-separated into a second phase smaller in amount than the first phase, and a surface layered on the intermediate layer and formed of composite nanoparticles (A) of a metal containing silver and a protective colloid. It is made up of layers.

In the surface layer and the interface layer, the composite nanoparticles (A) are arranged to form a dense thin film of silver-containing metal (silver-containing metal thin film), and in particular, the surface layer is a silver-containing metal thin film. By forming the silver luster film, the silver luster properties of the silver luster film are improved.

The average thickness of the surface layer is, for example, 3 to 300 nm, preferably 5 to 200 nm, more preferably 10 to 100 nm, more preferably 15 to 80 nm, most preferably 20 to 60 nm. If the average thickness of the surface layer is too thin, there is a possibility that the silver luster will be reduced, and if it is too thick, there is a possibility that the scratch resistance will be reduced.

The average thickness of the interfacial layer may be 300 nm or less, for example 3 to 300 nm, preferably 5 to 200 nm, more preferably 10 to 100 nm, more preferably 15 to 50 nm, most preferably 20 to 40 nm. If the average thickness of the interface layer is too thick, there is a risk that the adhesion will be reduced.

The intermediate layer is composed of a first phase containing a non-silicone resin (B) and the composite nanoparticles (A), and a second phase containing a silicone resin (C) and the composite nanoparticles (A). It suffices if it has a separate structure.

Since the non-silicone resin (B) has a higher affinity for the composite nanoparticles (A) than the silicone resin (C), the first phase has a higher affinity for the silver-containing metal (especially silver) than the second phase. The content ratio of metal nanoparticles is high.

In the first phase, the proportion of the silver-containing metal is, for example, 20 to 20,000 parts by mass, preferably 50 to 10,000 parts by mass, more preferably 100 to 100 parts by mass, per 100 parts by mass of the non-silicone resin (B). It is 5,000 parts by mass. If the proportion of silver is too small, there is a risk that the shielding properties will be reduced, and if it is too large, there is a possibility that the adhesion and scratch resistance will be reduced.

In the second phase, the proportion of the silver-containing metal may be 10,000 parts by mass or less, for example 0 to 5,000 parts by mass, preferably 0 to 3 parts by mass, based on 100 parts by mass of the silicone resin (C). ,000 parts by mass, more preferably 0 to 2,000 parts by mass. If the proportion of silver-containing metal is too high, there is a risk that adhesion and scratch resistance will decrease.

The phase separation structure may be a sea-island structure or a co-continuous structure. Among these, the sea-island structure is preferred.

When the intermediate layer has a sea-island structure, the continuous phase (matrix phase) constituting the sea portion may be the first phase or the second phase. Among these, it is preferable that the second phase is a continuous phase. By forming a continuous phase with the second phase having a low silver content, it is possible to achieve a high degree of coexistence between silver luster, adhesion, and scratch resistance.

In the sea-island structure, the average diameter of the dispersed phase is, for example, 5 to 3,000 nm, preferably 10 to 1,000 nm, more preferably 30 to 800 nm, more preferably 50 to 500 nm, most preferably 100 to 300 nm. If the average diameter of the dispersed phase is too small, there is a risk that the shielding properties will be reduced, and if it is too large, there is a risk that the adhesiveness and scratch resistance will be reduced. In the present application, when the shape of the dispersed phase is anisotropic, the average value of the major axis and the minor axis is defined as the diameter of each dispersed phase.

The average pitch of the dispersed phases (the average value of the distance between the centers of adjacent dispersed phases) is, for example, 5 to 2,500 nm, preferably 10 to 2,000 nm, more preferably 20 to 1,500 nm, and more preferably 30 to 2,000 nm. 1,000 nm, most preferably 50-500 nm. If the average pitch of the dispersed phase is too small, there is a risk that the adhesion and abrasion resistance will be reduced, and if it is too large, there is a risk that the shielding performance will be reduced.

The method for observing the cross section of the silver glossy film is not particularly limited, and any method used for ordinary structural analysis can be used. Observation methods include morphology and structure observation using transmission electron microscopes (TEM), scanning electron microscopes (SEM), electron beam microanalyzers (EPMA), scanning probe microscopes (SPM), etc.; fluorescent X-rays and energy dispersive Constituent elements can be analyzed by X-ray spectroscopy (EDX), wavelength dispersive X-ray spectroscopy (WDX), electron energy-loss spectroscopy (EELS), or the like. Among these, transmission electron microscopy (TEM) observation is particularly preferred since it allows observation of even the fine structure. A sample to be subjected to observation can be appropriately processed and used to make it suitable for observation and analysis. For example, a thin section sample may be prepared using a microtome or the like.

Therefore, in this application, the structure, size, and distribution state of the island structure in the cross section of the silver glossy film can be observed and measured based on the TEM image of the cross section of the silver gloss film, and the size is the average value of arbitrary 10 locations. . In detail, it can be measured by the method described in Examples below. Furthermore, in the TEM image, the silver-containing metal nanoparticles are dark-colored and can be easily confirmed, and in the intermediate layer, the aggregated portions of the silver-containing metal nanoparticles serve as the dispersed phase.

The average thickness of the intermediate layer is, for example, 0.05 to 100 μm, preferably 0.1 to 30 μm, more preferably 0.3 to 10 μm, more preferably 0.5 to 5 μm, and most preferably 1 to 3 μm. If the average thickness of the intermediate layer is too thin, there is a risk that the light shielding property will be reduced, or the adhesion and scratch resistance will be reduced, and if it is too thick, there is a risk that the silver luster will be reduced.

The average thickness of the intermediate layer may be twice or more (for example, 3 to 5,000 times) the average thickness of the surface layer, for example, 5 to 3,000 times, preferably 10 to 1,000 times, More preferably 20 to 500 times, more preferably 30 to 300 times, and most preferably 50 to 150 times. If the thickness ratio of the intermediate layer is too small, there is a risk that the adhesion and scratch resistance will be reduced, and if it is too large, there is a risk that the silver luster will be reduced.

In addition, in this application, the average thickness of each layer can be measured by observing the cross section of the silver luster film with a transmission electron microscope (TEM), and is the average value of three arbitrary locations.

The present invention will be explained in more detail below based on Examples, but the present invention is not limited by these Examples. In the following examples, the preparation method of the ink composition and the measurement method of the evaluation test are shown below.

[Materials used]
Acrylic resin A: "ARUFON UH2170" manufactured by Toagosei Co., Ltd., styrene acrylic resin (hydroxyl group-containing type acrylic polymer), nonvolatile content 98% or more, hydroxyl value 88 mgKOH/g, glass transition temperature 60 ° C., weight average molecular weight Mw14,000
Acrylic resin B: "WVU-120" manufactured by DIC Corporation, isocyanate-curing acrylic resin (acrylic polyol), non-volatile content 29.5%, hydroxyl value 10.2 mgKOH/g
Polyvinyl butyral resin: "S-LEC KS-10" manufactured by Sekisui Chemical Co., Ltd., degree of acetalization 70 mol% or more, acetyl group 3 mol% or less, hydroxyl group 25 mol%, 10% by mass Solution viscosity (temperature 20 ° C., rotational viscosity Type (BM type), solvent = toluene/ethanol = 50/50 (mass ratio)) 10 to 30 mPa・s, glass transition temperature 106°C, weight average molecular weight 17,000
Polyester resin: “ODX-2420” manufactured by DIC Corporation, polyester polyol, viscosity 5,600 mPa・s (25°C), average molecular weight 2,000, acid value 0.4 mgKOH/g, hydroxyl value 56 mgKOH/g
Alkyd resin: D-128-65BA manufactured by DIC Corporation, isocyanate curing alkyd resin, nonvolatile content 65%, hydroxyl value 90 mgKOH/g, acid value 5.0 mgKOH/g
Silicone resin A: "KR211" manufactured by Shin-Etsu Chemical Co., Ltd., methylphenyl silicone resin Silicone resin B: "RSN6018" manufactured by DOW Toray Industries, Inc., propylphenyl silicone resin Silicone resin C: manufactured by DOW Toray Industries, Inc. RSN0233", methylphenyl silicone resin Epoxy resin: "jER1055" manufactured by Mitsubishi Chemical Corporation, bisphenol F type epoxy resin Curing agent: "Burnock DN902S" manufactured by DIC Corporation, isocyanate compound 3-methoxy-3-methylbutanol: Manufactured by Tokyo Chemical Industry Co., Ltd., boiling point 174℃
Ethyl carbitol: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., boiling point 202°C
Butyl acetate: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., boiling point 126°C.

[Glossiness]
The 20° glossiness was measured using an appearance analyzer ("Rhopoint IQ-S" manufactured by Konica Minolta Japan, Inc.) and ranked (A, B, C) according to the following criteria. Note that when the glossiness value is 400 or more, metallic luster (mirror surface) can be visually confirmed, so ranks A and B were determined to be acceptable.

Rank A: Gloss level is 600 or higher (passed)
Rank B: Glossiness is 400 or more and less than 600 (pass)
Rank C: Glossiness is less than 400 (fail).

[Light opacity]
Visible light transmittance in the wavelength range of 380 to 780 nm was measured using an ultraviolet-visible near-infrared spectrophotometer ("UV-3100PC" manufactured by Shimadzu Corporation) and an integrating sphere ISR-3100. The integral value of the transmittance with respect to the integral value of the blank measurement (atmosphere) was determined by integrating the transmittance in the wavelength range of 380 to 780 nm, and evaluated according to the following criteria. The smaller the integral value of the transmittance for the blank measurement, the lower the permeability of the membrane, which is better.

○: Integral value of transmittance is 1.0% or less (pass)
△: Integral value of transmittance is greater than 1.0% and less than 5.0% (pass)
x: The integral value of transmittance is greater than 5.0% (fail).

[Adhesion]
Cellotape (registered trademark) was applied to the cured film, peeled off vigorously, and evaluated based on the following criteria.

○: No peeling in the film (passed)
×: There is peeling in the film (fail).

[Abrasion resistance]
The cured film was subjected to a friction test using a friction and abrasion tester with dry cotton under a load of 500 g and 10 reciprocations. The 20° glossiness of the cured film after the friction test was measured, the rate of decrease in glossiness before and after the friction test was determined, and the scratch resistance was evaluated according to the following criteria.

〇: Decrease rate of glossiness is less than 20% (pass)
△: Decrease rate of glossiness is 20% or more and less than 50% (pass)
×: Decrease rate of glossiness is 50% or more (fail).

[Comprehensive judgment]
Judgments were made based on the results of glossiness, light opacity, adhesion, and abrasion resistance, and grades A and B were considered acceptable.

A rating: Glossiness is rank A, light opacity, adhesion, and scratch resistance pass B rating: Glossiness is rank B, light opacity, adhesion, and scratch resistance pass C rating: Glossiness is rank B Rank C, or failure in any one of light opacity, adhesion, and scratch resistance.

[Cross-sectional observation of membrane]
A sample was cut out from the obtained shiny silver film, embedded in an epoxy resin which is a general-purpose embedding resin, and the cut cross section was exposed using a microtome and subjected to SEM observation. Furthermore, in order to observe the fine structure, after exposing the cut cross section with a microtome, we prepared ultrathin sections with a thickness of about 100 nm or less, performed TEM observation, and determined the size of the dispersed phase (average diameter and average pitch).

(Average diameter of dispersed phase)
The long axis and short axis of the dispersed phase (island) in which silver nanoparticles were aggregated were measured, and the average value was taken as the diameter of the dispersed phase (island). Then, the average value of the diameters calculated for ten arbitrary dispersed phases (islands) was taken as the average diameter of the dispersed phase.

(Average pitch of dispersed phase)
The intersection between the long axis and the short axis of the dispersed phase was set as the center of the dispersed phase, and the distance between the centers of adjacent dispersed phases was measured. The average value of the distances between the centers measured at arbitrary 10 locations was defined as the average pitch of the dispersed phase.

Examples 1 to 22 and Comparative Examples 1 to 5
(Preparation method of silver nanoparticle dispersion 1)
66.8 g of silver nitrate, a polymer dispersant having a carboxyl group ("Disperbic 190" manufactured by BIC Chemie), a solution of a high molecular weight block copolymer having a pigment affinity group, solvent: water, non-volatile components 40%, acid value 10 mg KOH /g, amine value 0) was added to 100 g of ion-exchanged water and vigorously stirred to obtain a suspension. To this suspension, 100 g of dimethylaminoethanol (manufactured by Wako Pure Chemical Industries, Ltd.) was gradually added so that the water temperature did not exceed 50°C, and then heated and stirred in a water bath at a water temperature of 50°C for 4 hours. did.

An excess amount of methanol was added to the silver nanoparticle dispersion and stirred, and then the silver nanoparticles were precipitated by centrifugation, and the supernatant liquid was removed. Methanol was added and stirred again, and then the silver nanoparticles were precipitated by centrifugation, and the supernatant liquid was removed. Diethylene glycol monobutyl ether was added to the methanol solution containing the obtained precipitate, and the mixed methanol was removed using an evaporator to obtain silver nanoparticle (composite nanoparticle) dispersion 1 with a silver content of 70% by mass. Regarding this dispersion, when the particle size of the silver nanoparticles was confirmed using a transmission electron microscope (manufactured by JEOL Ltd.), the number average particle size of the primary particles was about 20 nm.

(Preparation method of silver nanoparticle dispersion 2)
Using a polymer dispersant having a carboxyl group ("Disperbic 2015" manufactured by Bick Chemie, a solution of an acrylic copolymer having a pigment affinity group, solvent: water, non-volatile component 40%, acid value 10 mgKOH/g, amine value 0) Silver nanoparticle (composite nanoparticle) dispersion 2 was prepared in the same manner as silver nanoparticle dispersion 1 except for the following. Regarding the obtained silver nanoparticle dispersion liquid 2, the particle size of the silver nanoparticles was confirmed using a transmission electron microscope (manufactured by JEOL Ltd.), and the number average particle size of the primary particles was about 30 nm.

(Preparation method of silver/copper alloy nanoparticle dispersion)
65.58 g of silver nitrate, a polymer dispersant having a carboxyl group ("Disperbic 190" manufactured by Bick Chemie), a solution of a high molecular weight block copolymer having a pigment affinity group, solvent: water, non-volatile components 40%, acid value 10 mg KOH /g, amine value 0) was added to 100 g of ion-exchanged water and vigorously stirred to obtain suspension A.

Take 1.40 g of copper (II) nitrate trihydrate and 2.93 g of a 1 mol/L nitric acid aqueous solution, stir in a water bath at 50°C, dissolve copper (II) nitrate trihydrate, and prepare aqueous solution B. I got it.

The suspension A and the aqueous solution B were mixed with stirring to obtain a mixed solution of a polymer dispersant having a carboxyl group, silver nitrate, and copper nitrate.

To this mixture, 100 g of dimethylaminoethanol (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was gradually added so that the water temperature did not exceed 50°C, and then heated and stirred in a water bath at a water temperature of 50°C for 4 hours. did.

An excess amount of methanol was added to the resulting dispersion containing silver/copper alloy fine particles and stirred, and then the silver/copper alloy nanoparticles were precipitated by centrifugation, and the supernatant liquid was removed. Methanol was added and stirred again, and then the silver/copper alloy nanoparticles were precipitated by centrifugation, and the supernatant liquid was removed. By adding diethylene glycol monobutyl ether to the methanol solution containing the obtained precipitate and removing the mixed methanol with an evaporator, the ratio of copper to 100 parts by mass of silver is 1 part by mass, and the silver/copper alloy content is 70 parts by mass. A dispersion of silver/copper alloy nanoparticles (composite nanoparticles) in mass % was obtained. Regarding this dispersion, when the particle size of the silver nanoparticles was confirmed using a transmission electron microscope (manufactured by JEOL Ltd.), the number average particle size of the primary particles was about 20 nm.

(Method for preparing metallic ink composition)
The obtained composite nanoparticle dispersion, resin, and solvent were stirred and mixed in the proportions shown in Tables 1 to 5 using a stirring defoaming device (Kurabo Industries, Ltd. "Mazel Star") to form a metallic ink composition. Prepared. Note that the amounts of acrylic resin and curing agent in the table are the contents in terms of solid content. The metallic ink composition was applied to a glass substrate using a 20 μm applicator. Thereafter, it was heated on a 50°C hot plate for 10 minutes, and then heated on an 80°C hot plate for 120 minutes. The thickness of the resulting silver glossy film (dry thickness of the coating film) was about 2 μm.

The evaluation results of the obtained silver luster film are shown in Tables 1 to 5.

As is clear from the results in Table 1, two types of resins (acrylic resin A and silicone resin A) were used, the amount of resin relative to silver was fixed at 30% by mass, and the ratio of acrylic resin in the resin and silicone resin was Examples 1 to 8 in which the mass ratio of acrylic resin to silicone resin was varied from 95:5 to 5:95 were excellent in gloss, light non-transmission, adhesion, and scratch resistance.

Specifically, in Examples 1 and 2 where the amount of resin relative to the composite nanoparticles was 30% by mass and acrylic resin: silicone resin = 95:5, 90:10, gloss, light non-transmission, adhesion, and scratch resistance were improved. was at a passing level.

In addition, in Examples 3 to 5 in which the amount of resin relative to the composite nanoparticles was varied from 30% by mass to acrylic resin: silicone resin = 80:20 to 40:60, glossiness, light opacity, adhesion, and scratch resistance were obtained. The properties were excellent, and the gloss was superior to Examples 1 and 2.

Furthermore, in Examples 7 and 8, in which the amount of resin relative to the composite nanoparticles was 30% by mass, and acrylic resin: silicone resin = 10:90, 5:95, the glossiness and light non-transmission were the same as in Examples 1 and 2. The adhesiveness, adhesion and abrasion resistance were at an acceptable level.

On the other hand, in Comparative Examples 1 and 2 in which one type of resin was used, the glossiness and light opacity were insufficient.

Furthermore, in Comparative Example 3 in which no resin was added, the glossiness and light impermeability were excellent, but the adhesion and abrasion resistance were insufficient.

As is clear from Table 2, even in Examples 9, 10, and 11 in which the amount of resin relative to silver was varied to 10% by mass, 50% by mass, and 200% by mass, the gloss, light opacity, adhesion, and scratch resistance were It was excellent. Note that even in Example 12 in which the amount of resin was varied to 300% by mass relative to silver, the gloss level was at a practical level, although the gloss level was slightly lower.

On the other hand, when two types of resin (acrylic resin A, silicone resin A) were used and one type of resin (acrylic resin A) was used in contrast to Example 11 in which the resin amount was 200% by mass relative to the composite nanoparticles. In Comparative Example 4, the gloss and light opacity were insufficient.

As is clear from the results in Table 3, even in Example 13, in which an isocyanate-curing acrylic resin was used as the acrylic resin and an isocyanate (curing agent) was added, the gloss, light opacity, adhesion, and scratch resistance were excellent. Ta.

Furthermore, Examples 14 and 15 in which the types of silicone resin and acrylic resin were changed also had excellent gloss, light non-transmission, adhesion, and scratch resistance.

On the other hand, in Comparative Example 5, which used two types of resins, acrylic resin A and epoxy resin, the glossiness and light non-transmittance were insufficient.

As is clear from the results in Table 4, Example 16, which had the composition of Example 4 but changed the type of protective colloid contained in the silver nanoparticle dispersion, had a slightly lower gloss than Example 4, but still had a high gloss level. The other evaluations were the same as in Example 4.

Examples 17 (ethyl carbitol) and 18 (butyl acetate), in which the solvent type (3-methoxy-3-methylbutanol) was changed in the composition of Example 4, had the same results as Example 4.

In Example 19, in which the silver nanoparticle dispersion in the composition of Example 4 was changed to a silver/copper alloy nanoparticle dispersion, the gloss level was lower than that in Example 4 because it contained copper, but it was still at a high level. , and other evaluations were the same as in Example 4.

As is clear from the results in Table 5, two types of resins (acrylic resin A and silicone resin A) were used, and acrylic resin A was substituted for Example 4 in which the resin amount was 30% by mass relative to the composite nanoparticles. Examples 20 to 22 in which polyvinyl butyral resin, polyester resin, and alkyd resin were used also had excellent gloss, light impermeability, adhesion, and scratch resistance. In particular, Example 20 using polyvinyl butyral resin and Example 21 using polyester resin had slightly lower gloss levels than Example 4, but were at approximately the same level.

Note that cross-sectional photographs of the silver gloss films obtained in Examples 1 to 2, 4, 7 to 8, 11, 13, and 20 are shown in FIGS. 1 to 32.

In the silver glossy films of Examples 1 and 2, as is clear from FIGS. 1 and 5 showing the overall image and FIGS. 4 and 8 showing enlarged images of the inside of the film, the silver nanoparticles were not unevenly distributed inside the film and were uniform. It was dispersed in Furthermore, as is clear from FIGS. 2 and 6, which are enlarged images near the surface, and FIGS. 3 and 7, which are enlarged images near the interface with the substrate, the silver nanoparticles are aligned at the surface and the interface with the substrate. A thin continuous layer (thin layer) was formed.

In the silver gloss films of Examples 4, 11, and 13, as is clear from FIGS. 9, 21, and 25 showing the overall image, and FIGS. 12, 24, and 28 showing enlarged images of the inside of the film, silver nanoparticles were present inside the film. There was phase separation into a region where (dark colored particles in the photograph) aggregated (dispersed phase) and a region where silver nanoparticles were less aggregated (continuous phase). That is, the silver nanoparticles had a structure in which they were unevenly distributed in the dispersed phase. Furthermore, as is clear from FIGS. 10, 22, and 26, which are enlarged images near the surface, and FIGS. 11, 23, and 27, which are enlarged images near the interface with the base material, silver nano The particles were aligned to form a thin continuous layer (thin layer).

In addition, when the average diameter and average pitch of the dispersed phase (area where silver nanoparticles aggregated) in Example 4 were measured, the average diameter was 442 nm and the average pitch was 633 nm.

Moreover, when Example 4 and Example 11 were compared, Example 11 had a larger amount of resin than Example 4, so the proportion of the continuous phase was larger.

Furthermore, when the average diameter and average pitch of the dispersed phase (region where silver nanoparticles aggregated) in Example 13 were measured, the average diameter was 389 nm and the average pitch was 488 nm. Compared to Example 4, Example 13, in which the average diameter of the dispersed phase is smaller, has a slightly lower gloss than Example 4, but is superior in rank A, and has excellent light opacity, adhesion, and scratch resistance. It was the same. That is, in Example 13, an excellent silver gloss film was obtained regardless of the average diameter of the dispersed phase.

In the silver gloss films of Examples 7 to 8 and 20, as is clear from FIGS. 13, 17 and 29 showing the overall image and FIGS. 16, 20 and 32 showing enlarged images of the inside of the film, silver nanoparticles were present inside the film. There was phase separation into a region where (dark colored particles in the photograph) aggregated (continuous phase) and a region where silver nanoparticles were less agglomerated (dispersed phase). Furthermore, as is clear from FIGS. 14, 18, and 30, which are enlarged images near the surface, and FIGS. 15, 19, and 31, which are enlarged images near the interface with the base material, silver nano The particles were aligned to form a thin continuous layer (thin layer). The silver luster film of Example 20 had a higher concentration of silver nanoparticles in the continuous phase and had excellent silver luster than the silver luster films of Examples 7 and 8.

Cross-sectional photographs of the silver glossy film obtained in Comparative Example 1 are shown in FIGS. 33 to 36. In this silver gloss film, silver nanoparticles were uniformly dispersed throughout the film.

Cross-sectional photographs of the silver glossy film obtained in Comparative Example 4 are shown in FIGS. 37 to 40. In the cross-sectional photograph of the silver glossy film obtained in Comparative Example 4, the silver nanoparticles were uniformly dispersed throughout the film, and the concentration of silver nanoparticles was low because the amount of resin was large. Furthermore, no continuous layer (thin layer) of silver nanoparticles was observed on the surface or at the interface with the base material.

The ink composition of the present invention can be used to improve the decorativeness of various objects to be decorated (molded objects), such as automobile interior and exterior parts, emblems, mobile phones, notebook computers, and golf club shafts. It can be used for decorating cosmetic containers, painting, and ink for inkjet printing.

Claims (7)

Composite nanoparticles of metal containing silver and protective colloid (A), non-silicone resin (B), silicone resin containing C _1-4 alkyl C _6-10 aryl silicone resin (C) and solvent (D ). The ink composition according to claim 1, wherein the mass ratio of the non-silicone resin (B) and the silicone resin (C) is from 95/5 to 5/95. Claim 1 wherein the total proportion of the non-silicone resin (B) and the silicone resin (C) is 10 to 300 parts by mass based on 100 parts by mass of the silver-containing metal of the composite nanoparticles (A). or the ink composition according to 2. The ink composition according to any one of claims 1 to 3, wherein the non-silicone resin (B) is a resin having a hydroxyl group. 5. The non-silicone resin (B) is at least one selected from the group consisting of (meth)acrylic resin, polyvinyl acetal resin, and polyester resin. Ink composition. The ink composition according to any one of claims 1 to 5, wherein the solvent (D) contains at least one selected from the group consisting of esters, alkylene glycol monoalkyl ethers, and dialkylene glycol monoalkyl ethers. . The composite nanoparticle (A) is a particle in which a protective colloid is attached or coordinated to the surface of a silver nanoparticle, the average particle size of the silver nanoparticle is 1 to 100 nm, and the protective colloid is a carboxyl The ink composition according to any one of claims 1 to 6, comprising a polymer dispersant having a group or a salt thereof.