Ink compositions and their uses

Abstract

To provide an ink composition which is excellent in metallic luster even when using a naturally derived binder.SOLUTION: The ink composition is prepared which contains composite nanoparticles (A) of a silver-containing metal and a protective colloid, and a resin component (B) containing a cellulose-based resin and does not substantially contain a polyvinyl acetal-based resin. The cellulose-based resin may be at least one selected from the group consisting of a cellulose ester, a cellulose ether, and a cellulose ether ester. The resin component (B) may further contain at least one second resin selected from the group consisting of a polyester-based resin, a (meth)acrylic resin, an epoxy resin, and a silicone-based resin. The ratio of the resin component (B) may be 5-50 pts.mass based on 100 pts.mass of the silver-containing metal of the composite nanoparticles (A).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an ink composition useful for metallicizing various objects to be decorated, and to the same applications. [Background technology]

[0002] Metallic finishes are needed in a wide range of fields, such as automotive interior and exterior parts, emblems, electronic devices, cosmetic containers, and golf club shafts. To achieve a sense of luxury, a high level of metallic luster comparable to that of metal is required. In particular, silver has a high light reflectivity, giving it a beautiful metallic luster (metallicity, brilliance, and mirror-like finish), and is expected to be a suitable metal for sophisticated designs.

[0003] Methods for imparting metallic luster to an object to be decorated include foil stamping, vapor deposition, silver mirror plating using the silver mirror reaction, and chromium plating. In addition, methods for forming a metallic luster layer on a substrate include printing or coating with inks that use aluminum pigment as a luminous pigment, or inks that contain metal nanoparticles.

[0004] Foil stamping, vapor deposition, silver mirror plating, and chrome plating can impart a metallic luster similar to that of metal, but they are disadvantageous in terms of manufacturing costs due to their complex manufacturing processes and the need for specialized equipment. Furthermore, silver mirror plating has a high defect rate due to the occurrence of whitening, cracking, and uneven coloring characteristic of plating, as well as the plating of areas other than those intended. In addition, chrome plating has a significant environmental impact. In contrast to these methods, printing and coating using inks are inexpensive to manufacture and allow for a wide range of substrates to be selected.

[0005] Among inks, inks containing metal nanoparticles produce a metallic luster layer that is superior to inks using aluminum pigments (glossy pigments).

[0006] Japanese Patent Publication No. 2022-8103 (Patent Document 1) discloses an ink composition comprising composite nanoparticles of a silver-containing metal and a protective colloid, a non-silicone resin, a silicone resin (C), and a solvent (D).

[0007] Japanese Patent Publication No. 2022-142769 (Patent Document 2) discloses an ink composition comprising composite nanoparticles of a silver-containing metal and a protective colloid, a resin component including a polyvinyl acetal resin, and a solvent. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2022-8103 [Patent Document 2] Japanese Patent Publication No. 2022-142769 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] However, the inks using metal nanoparticles disclosed in Patent Documents 1 and 2 use silicone resin or polyvinyl acetal resin as essential binders, but do not take the global environment into consideration. In recent years, global environmental problems have become urgent, and in order to develop the economy in a sustainable way without damaging the global environment, the SDGs (Sustainable Development Goals) have become widely recognized as common development goals worldwide, and readily available natural resources The use of materials derived from natural sources is desired.

[0010] On the other hand, a common challenge with inks containing metal nanoparticles is that increasing the amount of resin, such as binders, prevents the formation of metallic luster (silver luster). Therefore, to achieve high metallic luster, the amount of resin had to be kept to a minimum. Reducing the amount of resin lowers adhesion to the substrate and abrasion resistance, so the use of topcoat and undercoat layers was necessary. In other words, metallic luster and adhesion are in a trade-off relationship, making it difficult to achieve both properties simultaneously using a simple method. Consequently, designing inks containing binders under the constraints of natural resources was extremely difficult.

[0011] Therefore, the object of the present invention is to provide an ink composition that exhibits excellent metallic luster, such as silver luster, even when using a binder derived from natural sources, and to provide the same for use in such ink compositions. [Means for solving the problem]

[0012] As a result of diligent research to achieve the above objectives, the inventors discovered that by combining composite nanoparticles of a silver-containing metal and protective colloid with a cellulose-based resin, metallic luster such as silver luster can be improved without using polyvinyl acetal resins, and thus completed the present invention.

[0013] In other words, an ink composition according to an embodiment of the present invention [1] comprises composite nanoparticles (A) of a silver-containing metal and a protective colloid, and a resin component (B) containing a cellulose-based resin, and substantially does not contain a polyvinyl acetal-based resin.

[0014] Aspect [2] of the present invention is an aspect in which, in aspect [1], the cellulose resin is at least one selected from the group consisting of cellulose esters, cellulose ethers, and cellulose ether esters.

[0015] Aspect [3] of the present invention is an aspect of aspect [1] or [2] in which the resin component (B) further comprises a second resin, and the second resin is at least one selected from the group consisting of polyester resins, (meth)acrylic resins, epoxy resins, and silicone resins.

[0016] Aspect [4] of the present invention is an aspect in which, in any aspect [1] to [3], the proportion of the resin component (B) is 5 to 50 parts by mass per 100 parts by mass of the silver-containing metal of the composite nanoparticle (A).

[0017] Aspect [5] of the present invention is an embodiment of any of the embodiments [1] to [4], further comprising a surface modifier (C).

[0018] Aspect [6] of the present invention is an aspect in which, in aspect [5], the proportion of the surface modifier (C) is 0.1 to 30 parts by mass per 100 parts by mass of the silver-containing metal of the composite nanoparticles (A).

[0019] Aspect [7] of the present invention is an aspect of any aspect [1] to [6] wherein the solvent (D) further comprises at least one selected from the group consisting of alkylene glycol monoalkyl ethers and dialkylene glycol monoalkyl ethers.

[0020] The present invention also includes, as embodiment [8], a method for producing a metallic gloss film, which includes a coating step of applying an ink composition according to any of embodiments [1] to [7] onto a substrate, and a drying step of drying the coating film formed with the ink composition to obtain a metallic gloss film.

[0021] The present invention also includes, in aspect [9], a metallic luster film comprising composite nanoparticles (A) of a silver-containing metal and a protective colloid, and a resin component (B) containing a cellulose-based resin.

[0022] The present invention also includes, in embodiment

[10] , a decorative body (metallic decorative body or metallic-looking molded body) comprising a substrate which is a body to be decorated and a metallic gloss film of embodiment [9] laminated on the substrate.

[0023] The present invention also includes, in aspect

[11] , a method of decorating (or metallically decorating) a substrate by laminating the metallic luster film of aspect [9] onto a substrate that is to be decorated.

[0024] In this application, the term "ink" is used synonymously with "ink," and "ink composition" is used synonymously with "coating or coating composition." [Effects of the Invention]

[0025] In this invention, since a composite nanoparticle of a silver-containing metal and protective colloid is combined with a cellulose-based resin without using a polyvinyl acetal resin, metallic luster (especially silver luster) can be improved. Furthermore, by unevenly distributing the silver-containing metal, the amount of resin component can be increased while maintaining metallic luster, thus achieving both metallic luster, adhesion, and abrasion resistance. Specifically, a metallic luster film can be formed with high adhesion to the object to be decorated without forming an overcoat or undercoat layer, thus improving adhesion and abrasion resistance in a simple manner. In addition, since a dense layer of silver-containing nanoparticles can be formed on the film surface, light shielding (opacity) is also greatly improved, further enhancing metallic luster (mirror finish). [Brief explanation of the drawing]

[0026] [Figure 1] Figure 1 shows a transmission electron microscope (TEM) image of a cross-section of the silver-lustered film obtained in Example 2. [Figure 2] Figure 2 shows a transmission electron microscope (TEM) image of the cross-section of the silver-lustered film obtained in Comparative Example 2. [Modes for carrying out the invention]

[0027] [Ink composition] The mechanism by which the ink (or coating) composition (or ink) of the present invention exhibits a high degree of metallic luster, particularly a silver luster (mirror finish), by including a cellulose-based resin as the resin component can be estimated as follows.

[0028] First, if the resin component consists solely of cellulose-based resin, it can be assumed that the molecular structure of the cellulose-based resin is influencing the result. Specifically, cellulose-based resins have hydrophobic groups (acyl groups, alkoxy groups, etc.) and hydrophilic groups (hydroxyl groups) in their molecular chains. When the resin component is only cellulose-based resin, the composite nanoparticles are unevenly distributed on either the hydrophobic or hydrophilic groups, resulting in areas on the cellulose-based resin molecular chain that contain relatively more composite nanoparticles and areas that contain fewer. In other words, a structure similar to a phase separation structure between dense and sparse phases of composite nanoparticles is created on the cellulose-based resin molecular chain. As a result, it can be assumed that the phase containing relatively more composite nanoparticles (the phase with high shielding) plays a role in shielding (preventing transmission of) light, resulting in the appearance of a high metallic luster.

[0029] On the other hand, when the resin component includes a cellulose-based resin as the first resin and a second resin, it can be assumed that the phase separation structure between the resins is influencing the results. That is, when a cellulose-based resin is combined with a second resin such as a (meth)acrylic resin, silicone resin, or epoxy resin, the first and second resins undergo phase separation, and the composite nanoparticles are unevenly distributed in one of the phases. Compared to phase separation on the molecular chain with cellulose-based resin alone, the phase separation with two types of resins results in a relatively larger size of the phase containing more composite nanoparticles. Therefore, compared to using cellulose-based resin alone, a light shielding effect (opacity) can be obtained even when the amount of resin relative to the silver-containing metal is increased, and a high degree of metallic luster can be obtained. For this reason, when combining the first and second resins, a larger amount of resin can be incorporated, further improving adhesion and abrasion resistance.

[0030] (A) Composite nanoparticles The ink composition (metallic ink composition) of the present invention contains composite nanoparticles (A) of a silver-containing metal and a protective colloid.

[0031] In the composite nanoparticle (A) described above, the composite form of the silver-containing metal (silver-containing metal) and the protective colloid is not particularly limited, and may be a composite in which the silver-containing metal nanoparticle is attached to or coordinated to the surface of the silver-containing metal nanoparticle, or a composite in which the surface of the silver-containing metal nanoparticle is coated. Since silver-containing metal nanoparticles have high coordination ability to the protective colloid (or dispersant), the protective colloid may coordinate to the surface of the silver-containing metal nanoparticles, thereby forming a composite in which the silver-containing metal nanoparticles are coated. When silver-containing metal nanoparticles are composited with a protective colloid, the dispersion stability of the silver-containing metal nanoparticles can be improved, the affinity with the resin component can be easily adjusted, and a phase-separated structure can be formed.

[0032] (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 (e.g., 2 to 80 nm), preferably 3 to 70 nm (e.g., 4 to 50 nm), and more preferably 5 to 40 nm (particularly 10 to 30 nm).

[0033] The silver-containing metal nanoparticles have the above-mentioned average particle size and exhibit a broad 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.

[0034] In silver-containing metal nanoparticles, the proportion of particles with a primary particle diameter of 100 nm or more is, on a mass basis, for example, 10% by mass or less (e.g., 0 to 8% by mass), preferably 5% by mass or less (e.g., 0.01 to 3% by mass), and more preferably 1% by mass or less (e.g., 0.02 to 0.5% by mass).

[0035] 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 the average value of any 10 particles.

[0036] (Metals containing silver) The silver-containing metal may be pure silver or an alloy of silver with another metal. The other metal is not particularly limited as long as it can be alloyed with silver, but examples include Cr, Mo, W, Ni, Pd, Pt, Cu, Au, Zn, In, Sn, and Pb. These other metals can be used individually or in combination of two or more. Of these other metals, Cu is preferred.

[0037] In the silver-containing metal, 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, and most preferably 100% by mass (pure silver). If the proportion of silver is too low, there is a risk that the metallic luster will decrease.

[0038] When the silver-containing metal is a combination of silver and other metals (especially copper), the proportion of the other metal is, for example, 0.01 to 10 parts by mass, preferably 0.03 to 5 parts by mass, and more preferably 0.05 to 3 parts by mass, per 100 parts by mass of silver.

[0039] (Protective colloid) The protective colloid may be a dispersant, and is often a non-volatile dispersant. In particular, it is preferable that the protective colloid contains a polymeric dispersant having a carboxyl group or a derivative group thereof. In this application, the carboxyl group also includes carboxyl groups in the form of acid anhydride groups.

[0040] The polymer dispersant (or polymer-type dispersant) may have at least carboxyl groups and be capable of dispersing silver-containing metal nanoparticles, and may be an amphiphilic polymer dispersant (or oligomeric dispersant).

[0041] Examples of the aforementioned polymer dispersants include those commonly used in the paint and ink fields for dispersing colorants. Typical polymer dispersants (amphiphilic polymer dispersants) include water-soluble or water-dispersible resins containing hydrophilic units (or hydrophilic blocks) formed from hydrophilic monomers.

[0042] Examples of the hydrophilic monomers include addition polymerizable monomers such as carboxyl group-containing monomers (unsaturated polycarboxylic acids such as (meth)acrylic acid, maleic acid, maleic anhydride or their acid anhydrides), sulfo group-containing monomers (such as styrene sulfonic acid), and hydroxyl group-containing monomers (such as hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, vinylphenol, etc.); and condensation polymerizable monomers such as ethylene oxide. 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 form a hydrophilic unit (or block) alone or in combination of two or more types. Preferred hydrophilic monomers are (meth)acrylic acid, maleic acid, maleic anhydride, and ethylene oxide.

[0043] The polymer dispersant only needs to have at least a carboxyl group, and may also have the functional groups 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 individually or in combination of two or more.

[0044] The polymeric dispersant may contain at least a hydrophilic unit (or hydrophilic block), and may be a single hydrophilic monomer or a copolymer thereof (e.g., polyacrylic acid or a salt thereof), or a copolymer of a hydrophilic monomer and a hydrophobic monomer. Examples of hydrophobic monomers (nonionic monomers) include (meth)acrylic acid esters [(meth)acrylic acid C, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate]. 1-20(Meth)acrylic monomers such as alkyl, cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate, aryl (meth)acrylates such as phenyl (meth)acrylate, benzyl (meth)acrylate, aralkyl (meth)acrylates such as 2-phenylethyl (meth)acrylate; styrene monomers such as styrene, α-methylstyrene, vinyltoluene; α-C 2-20 Olefin monomers such as olefins (ethylene, propylene, 1-butene, isobutylene, 1-hexene, 1-octene, 1-dodecene, etc.); addition polymerizable monomers such as vinyl carboxylate monomers such as vinyl acetate and vinyl butyrate; and C120 3-6 Examples include condensation polymerizable monomers such as alkylene oxides. Hydrophobic monomers may be used alone or in combination of two or more to form hydrophobic units.

[0045] The polymer dispersant for copolymers (e.g., copolymers of hydrophilic monomers and hydrophobic monomers) may be a random copolymer, an alternating copolymer, a block copolymer (e.g., a copolymer composed of a hydrophilic block made of hydrophilic monomers and a hydrophobic block made of hydrophobic monomers), a comb copolymer (or comb graft copolymer), etc. The structure of the block copolymer is not particularly limited and may be a diblock structure, a triblock structure (ABA type, BAB type), etc. Furthermore, in the comb copolymer, the main chain may be formed of the hydrophilic block or the hydrophobic block, or it may be formed of a hydrophilic block and a hydrophobic block. Block copolymers of hydrophilic blocks and hydrophobic blocks can also improve metallic luster.

[0046] As mentioned above, the hydrophilic unit can also be formed from a hydrophilic block (such as a polyalkylene oxide like polyethylene oxide). The hydrophilic block (such as a polyalkylene oxide) and the hydrophobic block (such as a polyolefin block) may be linked via linking groups such as ester bonds, amide bonds, ether bonds, or urethane bonds. These bonds may be formed, for example, by modifying the hydrophobic block (such as a polyolefin) with a modifying agent [such as an unsaturated carboxylic acid or its anhydride (such as maleic anhydride), lactam or aminocarboxylic acid, hydroxylamine, or diamine], and then introducing the hydrophilic block. Alternatively, a comb copolymer (a comb copolymer whose main chain is composed of hydrophobic blocks) may be formed by reacting (or bonding) a polymer obtained from a monomer having hydrophilic groups such as hydroxyl groups or carboxyl groups (such as the aforementioned hydroxyalkyl (meth)acrylate) with the hydrophilic monomer of the condensation system (such as ethylene oxide).

[0047] Furthermore, the balance between hydrophilicity and hydrophobicity may be adjusted by using hydrophilic nonionic monomers as copolymerization components. Examples of such components include monomers or oligomers having ethylene oxy units, such as 2-(2-methoxyethoxy)ethyl (meth)acrylate and polyethylene glycol mono(meth)acrylate (e.g., number average molecular weight 200-1,000). Alternatively, the balance between hydrophilicity and hydrophobicity may be adjusted by modifying (e.g., esterifying) hydrophilic groups (such as carboxyl groups).

[0048] In polymer dispersants having carboxyl groups, the carboxyl groups may be salts or acid anhydride groups. For example, at least some of the carboxyl groups may form salts (salts with amines, metal salts, etc.). However, polymer dispersants in which acid groups such as carboxyl groups do not form salts [i.e., polymer dispersants having free carboxyl groups] can be suitably used.

[0049] The acid value of a polymeric dispersant having a carboxyl group may be, for example, 1 mg KOH / g or more (e.g., 2 to 100 mg KOH / g), preferably 3 mg KOH / g or more (e.g., 4 to 90 mg KOH / g), more preferably 5 mg KOH / g or more (e.g., 6 to 80 mg KOH / g), and more preferably 7 mg KOH / g or more (e.g., 8 to 50 mg KOH / g), and is usually 3 to 30 mg KOH / g (particularly 5 to 20 mg KOH / g). In addition, the amine value of such a polymeric dispersant may be 0 (or nearly 0).

[0050] In the polymer dispersant, the position of the functional group is not particularly limited and may be on the main chain, on the side chain, or located on both the main chain and the side chain. Such a functional group may be, for example, a functional group derived from a hydrophilic monomer or hydrophilic unit (e.g., a functional group introduced by copolymerization of (meth)acrylic acid, maleic anhydride, ethylene oxide, etc.).

[0051] Polymeric dispersants containing carboxyl groups may be used alone or in combination of two or more types.

[0052] Furthermore, as a polymer dispersant, polymer dispersants (high molecular weight pigment dispersants) described in Japanese Patent Publication No. 2004-207558, etc., may be used. Also, the polymer dispersant may be synthesized or a commercially available product may be used. Specific examples of commercially available polymer dispersants (or dispersants composed of at least an amphiphilic dispersant) include the Solspers series [manufactured by Abyssia Co., Ltd.] such as Solspers 13240, Solspers 13940, Solspers 32550, Solspers 31845, Solspers 24000, Solspers 26000, Solspers 27000, Solspers 28000, Solspers 41090; DISPERBYK-160, DISPERBYK-161, DISPERBYK-162, DI The Disperbic series includes models such as SPERBYK-163, DISPERBYK-164, DISPERBYK-166, DISPERBYK-170, DISPERBYK-180, DISPERBYK-182, DISPERBYK-184, DISPERBYK-190, DISPERBYK-191, DISPERBYK-192, DISPERBYK-193, DISPERBYK-194, DISPERBYK-2001, DISPERBYK-2015, and DISPERBYK-2050. [Manufactured by Big Chemie Japan Co., Ltd.]; 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.]; Azisper PB711, Azisper PAl11, Azisper PB811, Azisper Examples include the Azisper series [manufactured by Ajinomoto Co., Inc.], such as Spar PB821 and Azisper PW911; the Floren series [manufactured by Kyoeisha Chemical Co., Ltd.], such as Floren DOPA-158, Floren DOPA-22, Floren DOPA-17, Floren TG-700, Floren TG-720W, Floren-730W, Floren-740W, and Floren-745W; and the Johncryl series [manufactured by Johnson Polymer Co., Ltd.], such as Johncryl 678, Johncryl 679, and Johncryl 62.Representative polymer dispersants include DISPERBYK-190, DISPERBYK-194, and DISPERBYK-2015.

[0053] The number-average molecular weight of the polymer dispersant, when measured by gel permeation chromatography (GPC), is, for example, 1,500 to 100,000, preferably 2,000 to 80,000 (e.g., 2,000 to 60,000), more preferably 3,000 to 50,000 (e.g., 5,000 to 30,000), and more preferably 7,000 to 20,000, in terms of polystyrene equivalent.

[0054] The polymeric dispersant having a carboxyl group may also be a polymeric dispersant that does not have a hydroxyl group.

[0055] The proportion of the protective colloid is, for example, 0.1 to 100 parts by mass (particularly 1 to 50 parts by mass) per 100 parts by mass of silver-containing metal. The proportion of the polymer dispersant having carboxyl groups can be selected from a range of, for example, 0.1 to 60 parts by mass (for example, 1 to 50 parts by mass) per 100 parts by mass of silver-containing metal, and is usually 2 to 40 parts by mass (for example, 2.5 to 30 parts by mass), more preferably 3 to 25 parts by mass (particularly 5 to 20 parts by mass).

[0056] In this application, the proportion of protective colloids in the composite nanoparticles (A) can be measured by conventional methods, such as thermal analysis (e.g., simultaneous thermogravimetric / differential thermal analysis).

[0057] The protective colloid may contain other dispersants if necessary, and these other dispersants may be inorganic compounds, but are usually organic compounds. Examples of other dispersants include alkanols (such as hexanol, octanol, decanol, dodecanol, octadecanol, etc.). 6-20 Alkane monools), aldehydes (such as caprylic aldehyde, lauryl aldehyde, palmitaldehyde, etc.) 6-20Examples include aliphatic aldehydes, aliphatic hydroxycarboxylic acids, higher fatty acids or their salts, and sulfonic acids (such as alkanesulfonic acids, benzenesulfonic acids, and arenesulfonic acids like toluenesulfonic acid). These other dispersants may be used alone or in combination of two or more.

[0058] The proportion of the other dispersant is, for example, 0.1 to 100 parts by mass, preferably 0.5 to 50 parts by mass, and more preferably 1 to 30 parts by mass, per 100 parts by mass of the polymer dispersant.

[0059] The method for producing the composite nanoparticles is not particularly limited, and conventional methods can be used. For example, if the silver-containing metal is elemental silver, the silver compound corresponding to the silver nanoparticles can be prepared by reducing it in a solvent in the presence of a protective colloid and a reducing agent. Specific production methods include, for example, the methods described in Japanese Patent Publication No. 2010-80442 and Japanese Patent Publication No. 2010-229544.

[0060] (B) Resin component The ink composition of the present invention comprises a resin component (B) containing a cellulose-based resin as a first resin. The resin component (B) may contain only the first resin (B1), or it may contain the first resin (B1) and the second resin (B2).

[0061] (B1) First resin The first resin (B1), a cellulose-based resin, is not particularly limited, but may be a cellulose derivative obtained by modifying or altering cellulose.

[0062] Examples of cellulose derivatives include cellulose ester, cellulose ether, and cellulose ether ester. Examples of cellulose esters include inorganic cellulose esters such as nitrocellulose, cellulose sulfate, and cellulose phosphate; and organic cellulose esters such as cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, and cellulose acetate propionate butyrate. Examples of cellulose ethers include cellulose alkyl ethers such as methyl cellulose, ethyl cellulose, ethyl methyl cellulose, ethyl propyl cellulose, isopropyl cellulose, and butyl cellulose; carboxyalkyl celluloses such as carboxymethyl cellulose; and hydroxyalkyl celluloses such as hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl methyl cellulose. Examples of cellulose ether esters include cellulose ether esters such as carboxymethyl cellulose acetate, carboxymethyl cellulose propionate, and carboxymethyl cellulose butyrate.

[0063] These cellulose derivatives can be used alone or in combination of two or more. Among these, organic cellulose esters and cellulose alkyl ethers are preferred.

[0064] As the organic cellulose ester, cellulose acylate is preferred, and cellulose C 2-6 acylate (for example, C 3-4 acylate) is more preferred, cellulose acetate C 3-6 acylate (for example, C 4-6 acylate) is even more preferred, and cellulose C 4-5 acylate (particularly cellulose acetate butyrate) is most preferred. The organic cellulose ester may be produced by a reaction between cellulose and an organic acid and / or an acid anhydride, and in particular, may be produced by triesterifying cellulose with an organic acid and / or an acid anhydride, followed by hydrolysis.

[0065] The degree of esterification of the cellulose acylate is, for example, 30 to 70% by mass, preferably 35 to 65% by mass, more preferably 40 to 60% by mass, and more preferably 45 to 55% by mass.

[0066] Cellulose acetate C 3-6 Acylates (especially cellulose acetate C) 3-4 The degree of acetyl substitution of the acylate is, for example, 0.5 to 30% by mass, preferably 0.8 to 20% by mass, and more preferably 1 to 10% by mass.

[0067] Cellulose acetate C 3-6 Acylates (especially cellulose acetate C) 3-4 C (Acidate) 3-6 Degree of acyl substitution (especially C 3-4 The degree of acyl substitution is, for example, 15 to 60% by mass, preferably 30 to 55% by mass, and more preferably 40 to 50% by mass.

[0068] In this application, the degree of esterification of cellulose acylate refers to the mass ratio of acyl groups in the cellulose acylate, and can be measured using conventional methods such as titration, gas chromatography, IR elemental analysis, and NMR, and may be measured in particular by gas chromatography.

[0069] Cellulose acetate C 3-6 Acylates (especially cellulose acetate C) 3-4 The hydroxyl group content of the acylate is, for example, 0.1 to 30% by mass, preferably 1 to 20% by mass, and more preferably 2 to 10% by mass, more preferably 3 to 8% by mass, and most preferably 4 to 6% by mass, in order to improve metallic luster.

[0070] In this application, the hydroxyl group content of cellulose acylate can be measured using conventional methods, such as titration, gas chromatography, IR elemental analysis, and NMR, and may be measured particularly by gas chromatography.

[0071] The number-average molecular weight of cellulose acylate is, for example, 1,000 to 300,000, preferably 5,000 to 100,000, more preferably 8,000 to 50,000, more preferably 10,000 to 30,000, and most preferably 15,000 to 25,000. If the molecular weight is too low, the mechanical properties of the metallic luster film may decrease, and conversely, if it is too high, the film-forming ability may decrease.

[0072] In this application, the number-average molecular weight of cellulose acylate is a value calculated from a chromatogram measured by gel permeation chromatography (GPC), based on the molecular weight of standard polystyrene.

[0073] The glass transition temperature of cellulose acylate can be selected from a range of approximately 80 to 180°C, for example, 90 to 170°C, preferably 100 to 160°C, more preferably 120 to 150°C, more preferably 125 to 145°C, and most preferably 130 to 140°C. If the glass transition temperature is too low, the mechanical properties of the metallic luster film may deteriorate, and conversely, if it is too high, the film-forming ability may deteriorate.

[0074] In this application, the glass transition temperature of cellulose acylate can be measured using a differential scanning calorimeter.

[0075] As for cellulose alkyl ethers, cellulose C 1-6 Alkyl ethers are preferred, and cellulose C 1-4 Alkyl ethers are more preferred, and cellulose C 2-3 Alkyl ethers are more preferred. Cellulose alkyl ethers may be produced by the reaction of alkali cellulose, obtained by alkali celluloseization of cellulose, with alkyl chloride.

[0076] The degree of ether substitution of the cellulose alkyl ether is, for example, 30 to 70% by mass, preferably 40 to 60% by mass, more preferably 45 to 55% by mass, and more preferably 48 to 50% by mass.

[0077] In this application, the degree of ether substitution of cellulose alkyl ether can be measured using conventional methods, such as titration, gas chromatography, IR elemental analysis, and NMR, and may be measured particularly by gas chromatography.

[0078] The number-average molecular weight of cellulose alkyl ethers is, for example, 1,000 to 300,000, preferably 10,000 to 200,000, more preferably 30,000 to 100,000, more preferably 50,000 to 70,000, and most preferably 60,000 to 65,000. If the molecular weight is too low, the mechanical properties of the metallic luster film may decrease, and conversely, if it is too high, the film-forming ability may decrease.

[0079] In this application, the number-average molecular weight of cellulose alkyl ethers is calculated from chromatograms measured by gel permeation chromatography (GPC) based on the molecular weight of standard polystyrene.

[0080] The glass transition temperature of cellulose alkyl ether is, for example, 80 to 180°C, preferably 100 to 150°C, more preferably 110 to 140°C, more preferably 120 to 140°C, and most preferably 125 to 135°C. If the glass transition temperature is too low, the mechanical properties of the metallic luster film may deteriorate, and conversely, if it is too high, the film-forming ability may deteriorate.

[0081] In this application, the glass transition temperature of cellulose alkyl ether can be measured using a differential scanning calorimeter.

[0082] Of these, cellulose acetate propionate and cellulose ether are preferred because they can improve metallic luster. Furthermore, cellulose acetate C is preferred because it can improve metallic luster when combined with a second resin. 4-6 Acylates and cellulose ethers are preferred, and cellulose acetate C 4-5Acylates and cellulose alkyl ethers are particularly preferred, with cellulose acetate butyrate being the most preferred.

[0083] (B2) Second resin The second resin (B2) is not particularly limited as long as it is a resin that can be phase-separated from the first resin, but examples include polyester resin (a), (meth)acrylic resin (b), epoxy resin (c), and silicone resin (d).

[0084] (a) Polyester resin Polyester resin (a) is a polymer synthesized by dehydrating and condensing polycarboxylic acid and polyol monomers to form ester bonds. The polyester resin (or polyester resin) in the present invention is not particularly limited, but examples include polyester polyol resin (a1) and alkyd resin (a2).

[0085] (a1) Polyester polyol resin Polyester polyol resin (or polyester polyols) (a1) is a polymer having ester bonds in its molecular chain and having two or more hydroxyl groups in one molecule.

[0086] Polyester polyol resins (a1) include, for example, polyester polyols obtained by esterifying a low molecular weight polyol with a polycarboxylic acid; polyester polyols obtained by ring-opening polymerization of a cyclic ester compound (lactone); polyester polyols obtained by reacting (adding) a cyclic ester compound with a polyol (for example, one or more selected from the group consisting of low molecular weight polyols, alkylene oxides, polyether polyols, polyester polyols, and polycarbonate polyols) as an initiator; and copolymerized polyester polyols of these.

[0087] As low molecular weight polyols used as raw materials for polyester polyol resin (a1), polyols with a molecular weight of approximately 50 to 300 can be used, for example, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, tetramethylene glycol, neopentyl glycol, 1,3- Examples include aliphatic diols such as butanediol (aliphatic diols with 2 to 10 carbon atoms); aliphatic triols such as glycerin, trimethylolpropane, and trimethylolethane; polyols with four or more functions such as pentaerythritol, diglycerin, ditrimethylolpropane, ditrimethylolethane, tris(2-hydroxyethyl) isocyanurate, and dipentaerythritol; polyols containing alicyclic structures such as 1,4-cyclohexanediol, cyclohexanedimethanol, and hydrogenated bisphenol A; bisphenol compounds such as bisphenol A and bisphenol F and their alkylene oxide adducts, and aromatic polyols such as p-hydroxyphenethyl alcohol.

[0088] These low molecular weight polyols can be used individually or in combination of two or more.

[0089] The polycarboxylic acid used as a raw material for polyester polyol resin (a1) is not particularly limited and includes, for example, aliphatic dicarboxylic acids such as succinic acid, succinic anhydride, alkenyl succinic acid, alkenyl succinic anhydride, fumaric acid, maleic acid, maleic anhydride, itaconic acid, adipic acid, azelaic acid, sebacic acid, dodecanediic acid, hymic acid, hymic anhydride, and dimer acid; alicyclic dicarboxylic acids such as tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, 1,4-cyclohexanedicarboxylic acid, and 1,3-cyclohexanedicarboxylic acid; phthalic acid, phthalic anhydride, terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, and di Examples include aromatic dicarboxylic acids such as phenic acid; oxypolycarboxylic acids such as 4,4-bis(p-hydroxyphenyl)valeric acid and 5-hydroxyisophthalic acid; aromatic dicarboxylic acids having a sulfonic acid group or a sulfonic acid base (metal salt, ammonium salt, etc.) such as sulfotephthalic acid, 5-sulfoisophthalic acid, 5-sodium sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, and 5-(4-sulfophenoxy)isophthalic acid; and polycarboxylic acids with three or more functions such as trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, methylcyclohexentricarboxylic acid, methylcyclohexentricarboxylic acid anhydride, and benzophenonetetracarboxylic acid.

[0090] These polycarboxylic acids can be used individually or in combination of two or more.

[0091] Examples of cyclic ester compounds used as raw materials for polyester polyol resin (a1) include C13, β-butyrolactone, δ-valerolactone, ε-caprolactone, etc. 4-8 Examples include lactones. These cyclic ester compounds can be used individually or in combination of two or more. Of these, ε-caprolactone is commonly used.

[0092] Examples of polyester polyols (raw materials for adding cyclic ester compounds) used as raw materials for polyester polyol resin (a1) include polyester polyols obtained by esterifying a low molecular weight polyol with a polycarboxylic acid.

[0093] Polyether polyols used as raw materials for polyester polyol resin (a1) include, for example, alkylene oxides alone or copolymers [poly(C) such as polyethylene glycol, polypropylene glycol, polytrimethylene ether glycol, polytetramethylene ether glycol]. 2-4 Examples include alkylene glycols, bisphenol A, or alkylene oxide adducts of hydrogenated bisphenol A.

[0094] Polycarbonate polyols used as raw materials for polyester polyol resin (a1) include, for example, the low molecular weight diol and dialkyl carbonate (such as dimethyl carbonate and other diC 1-4 Alkyl carbonates (such as alkyl carbonates) and diaryl carbonates (such as diphenyl carbonates) 6-12 Examples include reaction products with aryl carbonates, etc.

[0095] Polyester polyols, polyether polyols, and polycarbonate polyols can be used individually or in combination of two or more as raw materials for polyester polyol resin (a1).

[0096] The polyester polyol resin (a1) may optionally further contain oxycarboxylic acids such as p-hydroxyphenylpropionic acid, p-hydroxybenzoic acid, p-hydroxyphenylacetic acid, and 6-hydroxy-2-naphthoic acid as copolymerization components.

[0097] The polyester polyol resin (a1) may optionally contain trifunctional or more components as copolymerization components for the purpose of introducing a branched skeleton into the polycarboxylic acid component and / or polyol component.

[0098] The hydroxyl value of the polyester polyol resin (a1) is, for example, 5 to 500 mg KOH / g, preferably 10 to 300 mg KOH / g, more preferably 20 to 200 mg KOH / g, more preferably 30 to 150 mg KOH / g, and most preferably 50 to 100 mg KOH / g. If the hydroxyl value is too low, the silver luster and mechanical properties of the silver luster film may decrease, and conversely, if it is too high, the silver luster may decrease.

[0099] In this application, the hydroxyl value of the polyester polyol resin (a1) can be measured in accordance with JIS K 1557-1.

[0100] A carboxyl group may be introduced into the polyester polyol resin (a1). The acid value of the polyester polyol resin (a1) is preferably 0.1 to 10 mg KOH / g, and more preferably 0.2 to 5 mg KOH / g (e.g., 0.3 to 1 mg KOH / g).

[0101] In this application, the acid value of the polyester polyol resin (a1) can be calculated by titration according to the potassium hydroxide method.

[0102] One method for introducing carboxyl groups is to introduce carboxylic acids into polyester polyols by acid addition after polymerization. When monocarboxylic acids, dicarboxylic acids, or trifunctional or higher polycarboxylic acid compounds are used for acid addition, a decrease in molecular weight may occur due to transesterification; therefore, it is preferable to use compounds having at least one carboxylic acid anhydride group. Examples of carboxylic acid anhydrides include succinic anhydride, maleic anhydride, orthophthalic acid, 2,5-norbornenedicarboxylic acid anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride (PMDA), oxydiphthalic acid dianhydride (ODPA), 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride (BTDA), 3,3',4,4'-diphenyltetracarboxylic acid dianhydride (BPDA), 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride (DSDA), 4,4'-(hexafloysopropylidene)diphthalic acid dianhydride (6FDA), and 2,2'-bis[(dicarboxyphenoxy)phenyl]propane dianhydride (BSAA).

[0103] The weight-average molecular weight of the polyester polyol resin (a1) is, for example, 600 to 20,000, preferably 1,000 to 10,000, more preferably 1,300 to 5,000, and even more preferably 1,500 to 3,000. If the molecular weight is too low, the mechanical properties of the silver luster film may decrease, and conversely, if it is too high, the film-forming properties may decrease.

[0104] In this application, the weight-average molecular weight of the polyester polyol resin (a1) is a value calculated from a chromatogram measured by gel permeation chromatography (GPC) based on the molecular weight of standard polystyrene.

[0105] (a2) Alkyd resin Alkyd resin (a2) is a conventional alkyd resin used in the paint and coatings field, and may be, for example, short-oil alkyd resin, long-oil alkyd resin, modified alkyd resin, isocyanate-curable alkyd resin, epoxy ester resin (epoxy-modified alkyd resin), alkyd polyol, oil-free alkyd resin, etc.

[0106] The specific alkyd resin (a2) may be, for example, a synthetic resin defined in JIS K 5500 "Paint Terminology," that is, a synthetic resin obtained by polycondensation of a polycarboxylic acid (polybasic acid), a polyol (polyhydric alcohol), and, if necessary, an oil component.

[0107] Examples of polycarboxylic acids include those exemplified as raw materials for polyester polyol resin (a1). The polycarboxylic acids can be used alone or in combination of two or more. Among the polycarboxylic acids, aromatic dicarboxylic acids such as isophthalic acid and terephthalic acid are commonly used.

[0108] Oil components (fats and greases) include fatty oils (fats and greases) and / or fatty acids.

[0109] Examples of fatty oils include vegetable oils such as cottonseed oil, linseed oil, tung oil, castor oil, dehydrated castor oil, safflower oil, soybean oil, rice oil, corn oil, sesame oil, sunflower oil, rice bran oil, hemp oil, rapeseed oil, peanut oil, coconut oil, palm oil, kapok oil, tonsil oil, olive oil, tall oil, and elm oil; animal oils such as beef tallow, lard, sheep 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 versions of these oils. These oils can be used individually or in combination of two or more types.

[0110] Examples of fatty acids include straight-chain or branched-chain saturated carbon dioxide such as caprylic acid, capric acid, pelargonic acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, and behenic acid. 8-24Fatty acids; linear or branched unsaturated C2, such as myristoleic acid, palmitoleic acid, petroseric acid, oleic acid, vaccenic acid, linoleic acid, linolenic acid, eleostearic acid, gatolenic acid, arachidonic acid, and erucic acid. 8-24 Examples include fatty acids. 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 acids may also be fatty acids obtained from the aforementioned fatty oils by saponification or the like, for example, hydene fatty acids obtained from dehydrated castor oil, or fatty acids obtained from linseed oil, tung oil, dehydrated castor oil, soybean oil, safflower oil, etc. (e.g., linseed oil fatty acids, tung oil fatty acids, dehydrated castor oil fatty acids, soybean oil fatty acids, safflower oil fatty acids, etc.). These fatty acids can be used individually or in combination of two or more.

[0111] Among these oil components are vegetable oils such as linseed oil, tung oil, dehydrated castor oil, soybean oil, and safflower oil; fatty acids derived from these vegetable oils; and saturated carbon such as stearic acid. 10-22 Fatty acids; unsaturated C such as oleic acid, linoleic acid, linolenic acid, stearic acid, eleostearic acid, or ricinoleic acid. 10-22 Fatty acids are preferred.

[0112] Examples of polyols include low molecular weight polyols, as exemplified by polyester polyol resin (a1), as well as polyhydric alcohols that have been conventionally used in alkyd resins. These polyols can be used individually or in combination of two or more. Among these, aliphatic polyols such as glycerin, trimethylolpropane, pentaerythritol, and dipentaerythritol are commonly used.

[0113] The alkyd resin (a2) may further contain monobasic acids such as benzoic acid, pt-butylbenzoic acid, abietic acid, and hydrogenated abietic acid, in addition to polycarboxylic acids and polyols.

[0114] The hydroxyl value of the alkyd resin (a2) is, for example, 5 to 500 mg KOH / g, preferably 10 to 300 mg KOH / g, more preferably 20 to 200 mg KOH / g, and more preferably 50 to 150 mg KOH / g. If the hydroxyl value is too low, the metallic luster and the mechanical properties of the metallic luster film may decrease, and conversely, if it is too high, the metallic luster may decrease.

[0115] In this application, the hydroxyl value of the alkyd resin (a2) can be measured in accordance with ISO 4629(2).

[0116] The acid value of the alkyd resin (a2) is, for example, 0.5 to 30 mg KOH / g, preferably 1 to 20 mg KOH / g, more preferably 2 to 15 mg KOH / g, and more preferably 3 to 8 mg KOH / g. If the acid value is too low, the metallic luster may decrease, and conversely, if it is too high, the metallic luster and the mechanical properties of the metallic luster film may decrease.

[0117] In this application, the acid value of the alkyd resin (a2) can be measured in accordance with JIS K 5601-1-2.

[0118] The weight-average molecular weight of the alkyd resin (a2) 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 low, the mechanical properties of the metallic luster film may decrease, and conversely, if it is too high, the film-forming ability may decrease.

[0119] In this application, the weight-average molecular weight of the alkyd resin (a2) is a value calculated from a chromatogram measured by gel permeation chromatography (GPC) based on the molecular weight of standard polystyrene.

[0120] (b)(meth)acrylic resin The (meth)acrylic resin (b) is not particularly limited, but may be, for example, a single (meth)acrylic monomer or copolymer, a (meth)acrylic polyol, or a modified (meth)acrylic resin.

[0121] Examples of (meth)acrylic monomers include (meth)acrylic acid; methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, etc. 1-20 Alkyl; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate; aryl (meth)acrylates such as phenyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate and 2-phenylethyl (meth)acrylate; hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate. 1-4 Examples include alkyl (meth)acrylates. These (meth)acrylic monomers can be used individually or in combination of two or more. Among these, C (meth)acrylic acid such as methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate can be used. 1-4 Alkyl; hydroxyethyl (meth)acrylate and other hydroxy C 2-3 Alkyl (meth)acrylates are preferred.

[0122] The (meth)acrylic resin (b) may be a homopolymer of these monomers, but a copolymer is preferred. The copolymer may be a copolymer of two or more of the (meth)acrylic monomers, or a copolymer of the (meth)acrylic monomer and a copolymerizable monomer. Examples of copolymerizable monomers include styrene monomers such as styrene, α-methylstyrene, and vinyltoluene; α-C 2-20 Examples include olefin monomers such as olefins (ethylene, propylene, 1-butene, isobutylene, 1-hexene, 1-octene, 1-dodecene, etc.) and addition polymerizable monomers such as vinyl carboxylate monomers such as vinyl acetate and vinyl butyrate. These copolymerizable monomers can be used individually or in combination of two or more. Of these, styrene monomers such as styrene are preferred.

[0123] When the (meth)acrylic resin (b) is a copolymer of a (meth)acrylic monomer and a styrene monomer (particularly 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, and more preferably 70 / 30 to 30 / 70.

[0124] The (meth)acrylic polyol is not particularly limited as long as it is a (meth)acrylic polymer having two or more hydroxyl groups in its molecule. For example, hydroxy C is used as the monomer of the (meth)acrylic resin. 2-3 It may also be a (meth)acrylic resin containing alkyl (meth)acrylate.

[0125] 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, epoxy-modified (meth)acrylic resins such as epoxy (meth)acrylate, and silicone-modified (meth)acrylic resins such as silicone (meth)acrylate. These modified (meth)acrylic resins can be used individually or in combination of two or more types.

[0126] These (meth)acrylic resins can be used individually or in combination of two or more. Of these, (meth)acrylic resins having hydroxyl groups [particularly (meth)acrylic resins having multiple hydroxyl groups, such as isocyanate-curable (meth)acrylic resins] 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. (Meth)acrylic resins having hydroxyl groups and styrene units (e.g., methyl (meth)acrylate-hydroxyalkyl (meth)acrylate-styrene copolymers) are particularly preferred. The position of the hydroxyl groups is not particularly limited and may be in the main chain, in the side chain, or in both the main chain and side chain.

[0127] The acid value of (meth)acrylic resin (b) is, for example, 1 mg KOH / g or more (e.g., 1 to 200 mg KOH / g), preferably 2 mg KOH / g or more (e.g., 2 to 100 mg KOH / g), more preferably 3 mg KOH / g or more (e.g., 3 to 50 mg KOH / g), and more preferably 5 mg KOH / g or more (e.g., 5 to 10 mg KOH / g). If the acid value is too low, the metallic luster and the mechanical properties of the metallic luster film may decrease, and conversely, if it is too high, the metallic luster may decrease.

[0128] In this application, the acid value of (meth)acrylic resin (b) can be measured by conventional methods, such as neutralization titration.

[0129] The weight-average molecular weight of the (meth)acrylic resin (b) is, for example, 1,000 to 300,000, preferably 5,000 to 200,000, more preferably 10,000 to 100,000, more preferably 20,000 to 80,000, and most preferably 30,000 to 50,000. If the molecular weight is too low, the mechanical properties of the metallic luster film may decrease, and conversely, if it is too high, the film-forming properties may decrease.

[0130] In this application, the weight-average molecular weight of (meth)acrylic resin (b) is a value calculated from a chromatogram measured by gel permeation chromatography (GPC) based on the molecular weight of standard polystyrene.

[0131] The glass transition temperature of the (meth)acrylic resin (b) is, for example, 0 to 120°C, preferably 20 to 100°C, more preferably 30 to 80°C, and most preferably 40 to 60°C. If the glass transition temperature is too low, the mechanical properties of the metallic luster film may deteriorate, and conversely, if it is too high, the metallic luster and film-forming properties may deteriorate.

[0132] In this application, the glass transition temperature of (meth)acrylic resin (b) can be measured using a differential scanning calorimeter.

[0133] The (meth)acrylic resin (b) may be a (meth)acrylic resin that does not have a carboxyl group or a salt thereof.

[0134] (c) Epoxy resin The epoxy resin (c) may be a compound having two or more epoxy groups in its molecule. Epoxy resin (c) includes glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, and glycidyl ester type epoxy resins. Of these, glycidyl ether type epoxy resins are commonly used.

[0135] Examples of glycidyl ether type epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, bisphenol A novolac type epoxy resin, alcohol ether type epoxy resin, tetrabrom bisphenol A type epoxy resin, and naphthalene type epoxy resin.

[0136] These epoxy resins can be used individually or in combination of two or more. Of these, bisphenol-type epoxy resins, such as bisphenol A-type epoxy resins, are preferred.

[0137] The epoxy equivalent of epoxy resin (c) is, for example, 100 to 5,000 g / eq, preferably 300 to 3,000 g / eq, more preferably 500 to 1,500 g / eq, and more preferably 700 to 1,000 g / eq. If the epoxy equivalent of the epoxy resin is too low, the mechanical properties of the metallic luster film may decrease, and conversely, if it is too high, the metallic luster may decrease.

[0138] In this application, epoxy equivalent is defined as "the mass of epoxy resin containing one equivalent of epoxy groups," and can be measured in accordance with JIS K 7236.

[0139] The number-average molecular weight of epoxy resin (c) is, for example, 5,000 to 100,000, preferably 7,000 to 70,000, more preferably 10,000 to 40,000, and even more preferably 12,000 to 20,000. If the molecular weight is too low, the mechanical properties of the metallic luster film may decrease, and conversely, if it is too high, the film-forming properties may decrease.

[0140] In this application, the number-average molecular weight of the epoxy resin can be measured in accordance with the method described in JIS K 0124-2011, and is a value calculated from the chromatogram measured by gel permeation chromatography (GPC) based on the molecular weight of standard polystyrene.

[0141] The softening point of epoxy resin (c), as measured by a method conforming to JIS K 7234, is 30 to 150°C, preferably 50 to 130°C, more preferably 70 to 120°C, and more preferably 90 to 100°C. If the softening point is too low, the mechanical properties of the metallic luster film may deteriorate, and conversely, if it is too high, the film-forming properties may deteriorate.

[0142] In this application, the softening point of epoxy resin (c) is determined based on the ring-and-sphere method of JIS K 7234. The sample is filled into a specified ring, supported horizontally in a water bath or glycerin bath, a specified sphere is placed in the center of the sample, and the bath temperature is increased at a rate of 5°C per minute. The temperature is read when the sample enclosing the sphere comes into contact with the bottom plate of the ring stand.

[0143] (d) Silicone resin The silicone resin (d) is not particularly limited and may be a silicone resin or a silicone oligomer. Of these, a silicone resin is preferred because it can improve adhesion and abrasion resistance.

[0144] The silicone-based resin may be any thermoplastic resin, curable resin (uncrosslinked resin), or curable resin (crosslinked resin) having a polyorganosiloxane skeleton. The polyorganosiloxane skeleton is a linear, branched, or network compound having Si-O bonds (siloxane bonds), and is of formula: R 1 a SiO (4-a) / 2 (In the formula, R 1 The resin is composed of units represented by the formula (where R represents a substituent and the coefficient a is a number from 0 to 3). As a silicone resin, each unit represented by the formula is a monofunctional M unit (generally R 1 3SiO 1 / 2 (Units represented by the same unit), the difunctional D unit (generally R 1 2SiO 2 / 2 (Units represented by the trifunctional T unit (generally R) 1 SiO 3 / 2 (Units represented by SiO2), tetrafunctional Q units (generally SiO2) 4 / 2 Of the units represented by , polyorganosiloxanes that typically contain the T unit as the main unit are used.

[0145] In the above formula, substituent R 1 Examples include C groups such as methyl, ethyl, propyl, and butyl groups. 1-10 Halides such as alkyl groups, 3-chloropropyl groups, and 3,3,3-trifluoropropyl groups 1-10 C such as alkyl groups, vinyl groups, allyl groups, and butenyl groups 2-10 C groups such as alkenyl groups, phenyl groups, tolyl groups, and naphthyl groups. 6-20 C such as aryl groups, cyclopentyl groups, and cyclohexyl groups 3-10 C such as cycloalkyl groups, benzyl groups, and phenethyl groups 6-12 Aryl-C 1-4 Examples include alkyl groups. These substituents can be used individually or in combination of two or more.

[0146] Of these, R 1 Examples include C groups such as methyl and propyl groups. 1-4 C such as alkyl groups, phenyl groups, naphthyl groups, etc. 6-10An aryl group is preferred, C 1-3 Alkyl alkyl group, C 6-8 An aryl group is more preferred, and a methyl group and a phenyl group are most preferred. Furthermore, R 1 As such, it is preferable to use two or more types in combination rather than using them alone, because it improves compatibility with (meth)acrylic resins. 1-4 Alkyl and C 6-10 An aryl group is even more preferred, C 1-3 Alkyl and C 6-8 A combination with an aryl group is more preferable, and a combination of a methyl group and a phenyl group is most preferable.

[0147] C 1-4 Alkyl and C 6-10 When combined with an aryl group, the molar ratio of the two is C 1-4 Alkyl alkyl / C 6-10 The aryl group can be selected from a range of approximately 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, even more preferably 5 / 1 to 1.5 / 1, and most preferably 3 / 1 to 2 / 1.

[0148] The silicone resin may be a straight silicone resin (unmodified silicone resin) or a modified silicone resin. Examples of modified silicone resins include silicone resins modified with other resins such as alkyd resins, phenolic resins, urea resins, melamine resins, and epoxy resins.

[0149] Specifically, preferred silicone resins include substituent R 1 C such as a methyl group 1-4 C is an alkyl group 1-4 Alkyl silicone resins (for example, methyl silicone resins, etc.) 1-3 (Alkyl silicone resins, etc.), substituent R 1 is a phenyl group or C 6-10 The aryl group C 6-10 Aryl silicone resins (for example, phenyl silicone resins, etc.)6-8 aryl-based silicone resin), substituent R 1 is C 1-4 alkyl group and C 6-10 C which is a combination with an aryl group 1-4 alkyl C 6-10 aryl-based silicone resin (for example, C such as methylphenyl-based silicone resin, propylphenyl-based silicone resin, etc. 1-3 alkyl C 6-8 aryl-based silicone resins, etc.). These silicone resins can be used alone or in combination of two or more. From the viewpoint of improving adhesion and scratch resistance, C 1-4 alkyl C 6-10 alkylaryl-based silicone resins such as aryl-based silicone resins are preferred, and C such as methylphenyl-based silicone resins 1-2 alkyl C 6-8 aryl-based silicone resins are particularly preferred.

[0150] (Characteristics and Proportion of Second Resin) These second resins can be used alone or in combination of two or more. Among these second resins, from the viewpoint of excellent metallic luster, at least one selected from the group consisting of alkyd resins, (meth)acrylic resins (b), epoxy resins (c) and silicone resins (d) is preferred, and epoxy resins (c) and / or silicone resins (d) are particularly preferred.

[0151] In particular, when the first resin (cellulose-based resin) is cellulose acetate propionate, from the viewpoint of improving metallic luster, the second resin is preferably epoxy resin (c) and silicone-based resin (d), and silicone-based resin (d) is particularly preferred.

[0152] Further, when the first resin (cellulose-based resin) is cellulose acetate C 4-6 acylate (especially cellulose acetate butyrate), from the viewpoint of improving metallic luster, the second resin is preferably epoxy resin (c).

[0153] Furthermore, the first resin (cellulose-based resin) contains cellulose ether (especially cellulose C 2-3 In the case of an alkyl ether, the second resin is preferably an epoxy resin (c) or a silicone-based resin (d), with epoxy resin (c) being particularly preferred, as it can improve metallic luster.

[0154] The mass ratio of the first resin (cellulose-based resin) to the second resin can be selected from a range of approximately 100 / 0 to 5 / 95 (particularly 99 / 1 to 5 / 95), for example 95 / 5 to 5 / 95 (e.g., 90 / 10 to 10 / 90), preferably 80 / 20 to 20 / 80, more preferably 70 / 30 to 30 / 70, and more preferably 60 / 40 to 40 / 60. If the proportion of the second resin is too high, the metallic luster may decrease. In applications where metallic luster is important, the ratio of the first resin to the second resin may be 100 / 0 to 30 / 70, preferably 98 / 2 to 35 / 65, more preferably 95 / 5 to 40 / 60, more preferably 93 / 7 to 45 / 55, and most preferably 92 / 8 to 50 / 50.

[0155] (Proportion and properties of resin component (B)) The proportion of resin component (B) can be selected from a range of about 3 to 150 parts by mass per 100 parts by mass of silver-containing metal in the composite nanoparticles (A), for example, 5 to 120 parts by mass, preferably 7 to 100 parts by mass, more preferably 8 to 60 parts by mass, more preferably 10 to 50 parts by mass, and most preferably 20 to 40 parts by mass. In particular, in terms of excellent balance between metallic luster, adhesion and abrasion resistance, the proportion of resin component (B) can be selected from a range of about 3 to 60 parts by mass per 100 parts by mass of silver-containing metal in the composite nanoparticles (A), for example, 5 to 50 parts by mass, preferably 6 to 40 parts by mass, more preferably 7 to 35 parts by mass, more preferably 8 to 25 parts by mass, and most preferably 9 to 15 parts by mass. If the proportion of resin component (B) is too low, adhesion and abrasion resistance may decrease, and if it is too high, metallic luster may decrease.

[0156] The ink composition of the present invention substantially does not contain polyvinyl acetal resins (particularly polyvinyl butyral resins) as resin component (B), but it is especially preferable that it does not contain polyvinyl acetal resins.

[0157] (C) Surface modifier The ink composition of the present invention may contain a surface modifier (C). The surface modifier (C) only needs to have the ability to reduce surface tension, and conventional surface modifiers can be used. Examples of conventional surface modifiers include (meth)acrylic surface modifiers, silicone surface modifiers, fluorine-based surface modifiers, and acetylene glycol-based surface modifiers. These surface modifiers can be used alone or in combination of two or more. Of these, at least one selected from the group consisting of (meth)acrylic surface modifiers (C1) and silicone-based surface modifiers (C2) is preferred because it can effectively improve metallic luster.

[0158] (C1)(meth)acrylic surface modifier The (meth)acrylic surface modifier (C1) can be any surface modifier having a (meth)acrylic skeleton. Examples of the (meth)acrylic skeleton include homopolymers or copolymers of (meth)acrylic monomers. Examples of the (meth)acrylic monomers include (meth)acrylic acid and (meth)acrylic acid esters, with (meth)acrylic acid esters being preferred.

[0159] Examples of (meth)acrylic acid esters include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; polyoxyalkylene glycol (meth)acrylates (polyether (meth)acrylates) such as diethylene glycol (meth)acrylate, dipropylene glycol (meth)acrylate, and polyoxytetramethylene glycol (meth)acrylate; polyester (meth)acrylate; polyether ester (meth)acrylate; and silicone (meth)acrylate. These (meth)acrylic acid esters can be used alone or in combination of two or more. Among these, C (meth)acrylate 1-10 Alkyl (meth)acrylates such as alkyl, polyether (meth)acrylates, and silicone (meth)acrylates are preferred.

[0160] The (meth)acrylic surface modifier (C1) may be a surface modifier in which a polyether macromer and / or silicone macromer is introduced into the main chain of a homopolymer or copolymer of (meth)acrylic monomers, and in particular, a surface modifier in which the polyether macromer and / or silicone macromer is graft polymerized into the main chain.

[0161] These (meth)acrylic surface modifiers can be used individually or in combination of two or more. A preferred (meth)acrylic surface modifier (C1) is (meth)acrylic acid C 1-10 Examples include copolymers of alkyl (meth)acrylates such as alkyl groups and (poly)oxyalkylene glycol (meth)acrylate.

[0162] As the (meth)acrylic surface conditioner (C1), commercially available (meth)acrylic surface conditioners can be used. Examples of commercially available (meth)acrylic surface conditioners include BYK series surface conditioners manufactured by BYK-Chemie Japan Co., Ltd. ("BYK-350", "BYK-354", "BYK-355", "BYK-356", "BYK-358N", "BYK-361N", "BYK-381", "BYK-392", "BYK-394", "BYK-3440", "BYK-3441", etc.).

[0163] (C2) Silicone-based surface conditioner The silicone-based surface conditioner (C2) only needs to be a surface conditioner having a polyorganosiloxane skeleton. The polyorganosiloxane skeleton includes monofunctional M units (generally R 2 3SiO 1 / 2 units represented by ), difunctional D units (generally R 2 2SiO 2 / 2 units represented by ), trifunctional T units (generally R 2 SiO 3 / 2 units represented by ), and tetrafunctional Q units (generally SiO 4 / 2 units represented by ), any polyorganosiloxane formed of the above units is acceptable, but polyorganosiloxane formed of D units is usually used.

[0164] In the above formula of polyorganosiloxane, the substituent R 2 can be selected from hydrocarbon groups, but usually C 1-4 alkyl groups such as methyl group, ethyl group and propyl group; aryl groups such as phenyl group and naphthyl group are used, and methyl group and phenyl group (particularly methyl group) are preferred. The number of repetitions (degree of polymerization) of siloxane units is, for example, 2 to 3000, preferably 3 to 2000, more preferably 5 to 1000.

[0165] The polyorganosiloxane skeleton may be a modified polyorganosiloxane (modified silicone) obtained by introducing a modifying group into the main chain or side chain of a polyorganosiloxane skeleton (such as polydimethylsiloxane). Examples of modifying groups include polyether groups, polyester groups, radical polymerizable groups, and aralkyl groups.

[0166] Examples of polyether groups include polyoxyethylene groups, polyoxypropylene groups, polyoxybutylene groups, polyoxyethylene-polyoxypropylene groups, and other polyoxy C groups. 2-4 Examples include alkylene groups. In polyether groups, the number of repeating oxyalkylene groups (number of added moles) is, for example, 2 to 1000, preferably 3 to 100, and more preferably 5 to 50. Among these, polyoxyethylene and polyoxypropylene are examples of polyoxyC 2-3 Alkylene groups (particularly polyoxyethylene groups) are preferred.

[0167] Examples of polyester groups include polyester groups formed by the reaction of dicarboxylic acids (such as aromatic carboxylic acids like terephthalic acid or aliphatic carboxylic acids like adipic acid) with diols (such as aliphatic diols like ethylene glycol), and polyester groups formed by the ring-opening polymerization of cyclic esters (for example, lactones like caprolactone).

[0168] Examples of radical polymerizable groups include (meth)acryloyloxy groups and vinyl groups. Of these, (meth)acryloyloxy groups are commonly used.

[0169] Aralkyl groups include C groups such as benzyl and phenethyl. 7-18 Examples include aralkyl groups.

[0170] These modifying groups can be used individually or in combination of two or more. Of these modifying groups, polyether groups, polyester groups, and aralkyl groups are preferred, with polyester groups being particularly preferred.

[0171] The silicone-based surface modifier (C2) may have hydroxyl groups in order to improve adhesion and abrasion resistance. The hydroxyl groups may be present in the polyorganosiloxane skeleton, or in the case of a modified polyorganosiloxane skeleton, they may be present in the polyorganosiloxane skeleton, or they may be present in modified groups such as polyether groups, polyester groups, or (meth)acryloyl groups.

[0172] These silicone-based surface modifiers can be used individually or in combination of two or more. Preferred silicone-based surface modifiers (C2) include polyether-modified silicone-based surface modifiers, polyether-modified silicone-based surface modifiers having hydroxyl groups, polyester-modified silicone-based surface modifiers, polyester-modified silicone-based surface modifiers having hydroxyl groups, and aralkyl-modified silicone-based surface modifiers. Particularly preferred silicone-based surface modifiers (C2) are polyester-modified silicone-based surface modifiers having hydroxyl groups.

[0173] As the silicone-based surface conditioner (C2), commercially available silicone-based surface conditioners can be used. Examples of commercially available silicone-based surface conditioners include the BYK series manufactured by BYK Chemie Japan Co., Ltd. ("BYK-300", "BYK-306", "BYK-310", "BYK-322", "BYK-323", "BYK-333", "BYK-370", "BYK-375", "BYK-SILCLEAN3700", "BYK-SILCLEAN3720", etc.).

[0174] (Preferred form and proportion of surface modifier (C)) As for the surface modifier (C), when the first resin is a cellulose-based resin, a silicone-based surface modifier (C2) is preferred because it can greatly improve metallic luster, and when a second resin is used, a (meth)acrylic-based surface modifier (C1) is preferred because it easily improves metallic luster.

[0175] The proportion of these surface modifiers (C) is, for example, 0.1 to 30 parts by mass, preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, more preferably 2 to 10 parts by mass, and most preferably 3 to 7 parts by mass, per 100 parts by mass of the silver-containing metal of the composite nanoparticles (A). If the proportion of surface modifiers (C) is too low, the metallic luster may decrease, and if it is too high, the metallic luster, adhesion, and abrasion resistance may decrease.

[0176] (D) Solvent The ink composition of the present invention may further contain a solvent (D) in addition to the composite nanoparticles (A) and resin component (B). By blending the solvent (D) with the resin component (B), film-forming properties can be improved, and if the resin component (B) contains a second resin, phase separation by spinodal decomposition can also be promoted.

[0177] The solvent (D) preferably contains a polar organic solvent. Examples of polar organic solvents include alcohols (methanol, ethanol, propanol, isopropanol, etc.). 1-4 Alkanols, etc.; polyhydric alcohols (such as ethylene glycol, propylene glycol, and other alkanediols; such as glycerin, trimethylolpropane, and alkanetetraols, such as pentaerythritol, etc.); amides (such as formamide, acetamide, and other acylamides; mono- or di-C methylformamide, N-methylacetamide, N,N-dimethylformamide, and N,N-dimethylacetamide, etc.) 1-4(such as acylamides), 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 (such as acetic acid), esters (such as methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, amyl acetate, and other acetate esters), alkylene glycol monoalkyl ethers (such as methyl cellosolve, ethyl cellosolve, propyl cellosolve, butyl cellosolve, propylene glycol methyl ether, 3-methoxy-3-methyl-1-butanol, etc.) 2-6 Alkylene glycol mono C 1-4 Dialkylene glycol monoalkyl ethers (such as alkyl ethers), dialkylene glycol monoalkyl ethers (such as methyl carbitol, ethyl carbitol, propyl carbitol, butyl carbitol, etc.) 2-6 Alkylene glycol mono C 1-4 Alkyl ethers, etc., cellosolve acetates (such as ethyl cellosolve acetate) 1-4 Alkyl cellosolve acetates, carbitol acetates (such as methyl carbitol acetate and butyl carbitol acetate) 1-4 Examples include alkylcarbitol acetates and dimethyl sulfoxides. These polar organic solvents can be used individually or in combination of two or more.

[0178] The proportion of the polar organic solvent may be 50% by mass or more in the solvent, preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, and may also be 100% by mass.

[0179] The solvent (D) may further contain a nonpolar solvent in addition to the polar solvent. Examples of nonpolar solvents 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) per 100 parts by mass of the polar organic solvent, preferably 30 parts by mass or less, and more preferably 10 parts by mass or less.

[0180] It is preferable that these solvents include one or more selected from alcohols, esters, alkylene glycol monoalkyl ethers, and dialkylene glycol monoalkyl ethers; more preferably that they include one or more selected from esters, alkylene glycol monoalkyl ethers, and dialkylene glycol monoalkyl ethers; and even more preferably that they include one or more selected from alkylene glycol monoalkyl ethers and dialkylene glycol monoalkyl ethers. In particular, C 2-6 Alkylene glycol mono C 1-6 Alkyl ethers and diC 2-6 Alkylene glycol mono C 1-6 One or more selected from alkyl ethers are more preferably C 2-5 Alkylene glycol mono C 1-4 Alkyl ethers and diC 2-5 Alkylene glycol mono C 1-4 One or more selected alkyl ethers are most preferred. The dialkylene glycol monoalkyl ether may be a polar solvent derived from a dispersion medium for dispersing the silver colloid particles as a raw material.

[0181] The proportion of solvent (D) is, for example, 50 to 1,000 parts by mass, preferably 100 to 500 parts by mass, more preferably 200 to 450 parts by mass, more preferably 250 to 400 parts by mass, and most preferably 300 to 350 parts by mass, per 100 parts by mass of silver-containing metal of the composite nanoparticles (A). If the proportion of solvent is too low, the film-forming ability may decrease, and conversely, if it is too high, productivity and film-forming ability may decrease.

[0182] (E) Hardener The ink composition of the present invention may further contain a curing agent (E) in addition to the composite nanoparticles (A) and resin component (B). Examples of conventional curing agents (E) include isocyanate-based curing agents, amine-based curing agents, acid anhydride-based curing agents, and imidazole-based curing agents. Of these, isocyanate-based curing agents are preferred, and polyisocyanates are particularly preferred. Isocyanate-based curing agents such as polyisocyanates are particularly effective when the first resin and the second resin have functional groups (especially hydroxyl groups).

[0183] Examples of polyisocyanates include aliphatic polyisocyanates [diisocyanates such as propylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMDI), lysine diisocyanate (LDI); tri or polyisocyanates such as 1,6,11-undecane triisocyanate methyloctane, 1,3,6-hexamethylene triisocyanate], and alicyclic polyisocyanates [cyclohexane 1,4-diisocyanate, isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate]. Examples include diisocyanates such as socianates, hydrogenated bis(isocyanatophenyl)methane, tri or polyisocyanates such as bicycloheptane triisocyanate, and aromatic polyisocyanates such as phenylene diisocyanate, tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), naphthalene diisocyanate (NDI), bis(isocyanatophenyl)methane (MDI), tolidine diisocyanate (TODI), and 1,3-bis(isocyanatophenyl)propane; tri or polyisocyanates.

[0184] Polyisocyanates may be derivatives such as polymers (dimers, trimers, tetramers, etc.), adducts, or modified forms (biuret modified forms, alohanate modified forms, urea modified forms, etc.), or urethane oligomers having multiple isocyanate groups. Examples of modified forms or derivatives of polyisocyanates include adducts of polyisocyanates (such as aliphatic polyisocyanates like hexamethylene diisocyanate) and polyhydric alcohols (such as trimethylolpropane or pentaerythritol), biuret forms of the polyisocyanates, and polymers of the polyisocyanates (e.g., aliphatic polyisocyanates) (e.g., polyisocyanates having an isocyanurate ring, such as a trimer of hexamethylene diisocyanate).

[0185] These polyisocyanates can be used individually or in combination of two or more. Among these polyisocyanates, aliphatic polyisocyanates or their derivatives (e.g., HDI or its trimers) and aromatic polyisocyanates (TDI, MDI, etc.) are commonly used.

[0186] The proportion of the curing agent (E) is, for example, 10 to 200 parts by mass, preferably 20 to 150 parts by mass, and more preferably 25 to 100 parts by mass, per 100 parts by mass of the resin component (B).

[0187] (F) Other metal nanoparticles The ink composition of the present invention may further contain other metal nanoparticles (F) in addition to the composite nanoparticles (A) and resin component (B). Examples of other metal nanoparticles (F) include Group 8 metals of the periodic table (iron, nickel, cobalt, ruthenium, rhodium, palladium, rhenium, iridium, platinum, etc.), Group 1B metals of the periodic table (copper, gold, etc.), Group 3B metals of the periodic table (aluminum, gallium, indium, etc.), and Group 4B metals of the periodic table (germanium, tin, lead, etc.). The metal (metal atom) is often a metal with high coordination to the protective colloid, such as Group 8 metals or Group 1B metals 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, and more preferably 10 parts by mass or less, per 100 parts by mass of silver-containing metal of the composite nanoparticles (A).

[0188] (G) Other ingredients The ink composition of the present invention may further contain, to the extent that it does not impair the effects of the present invention, other components (G) such as conventional additives, for example, plasticizers (or film-forming aids), gloss enhancers, metal corrosion inhibitors (rust inhibitors), stabilizers (antioxidants, UV absorbers, light stabilizers, etc.), surfactants (anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, especially anionic surfactants and / or nonionic surfactants), dispersion stabilizers, thickeners or viscosity modifiers, humectants, thixotropy enhancers, leveling agents, penetrating agents, defoamers, pH adjusters, chelating agents, colorants (dye pigments, etc.), hue improvers, dye fixatives, bactericides, fungicides, preservatives, oxygen absorbers, etc. The surfactant may be an acetylene glycol-based surfactant, a polysiloxane-based surfactant, a fluorine-based surfactant, etc. These additives can be used individually 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, and more preferably 10 parts by mass or less, per 100 parts by mass of the silver-containing metal of the composite nanoparticle (A).

[0189] [Method for preparing an ink composition] The ink composition of the present invention can be prepared by mixing the composite nanoparticles (A), the resin component (B), and the surface modifier (C) in a conventional manner. A conventional stirring device can be used as the mixing method, for example, a stirring and defoaming device may be used. If the ink composition contains a solvent (D), the composite nanoparticles (A) may be mixed with the resin component (B) and the alkylene glycol monoalkyl ether as the solvent (D) in the form of a dispersion in which the composite nanoparticles (A) are dispersed in a dialkylene glycol monoalkyl ether as the solvent (D).

[0190] [Method for manufacturing a metallic luster film] The metallic luster film is obtained through a coating step in which the ink composition is applied to the object to be decorated (substrate) to form a coating film, and a drying step in which the coating film is dried to obtain the metallic luster film.

[0191] In the coating process, there are no particular restrictions on the type of substrate; resin substrates (films, etc.), metal substrates, glass substrates, ceramic substrates, paper, etc., can be used depending on the application.

[0192] The coating method is not particularly limited, and conventional coating methods such as flow coating, dispenser coating, spin coating, spray coating, screen printing, flexographic printing, casting, bar coating, curtain coating, roll coating, gravure coating, dipping, slitting, photolithography, inkjet, and offset printing can be used.

[0193] 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 more preferably 1 to 5 μm.

[0194] In this invention, metallic luster, adhesion, and abrasion resistance can be achieved simultaneously without forming an undercoat layer or topcoat layer; however, an undercoat layer and / or a topcoat layer may be used in combination depending on the application.

[0195] In the drying process, a metallic luster film is formed by drying the coating film. As for the drying method of the coating film, a heating method is preferred, and a two-stage heating method combining a preheating treatment and a main heating treatment is preferred because it facilitates the formation of a phase separation structure.

[0196] In the preheating process, 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.

[0197] In this heat treatment, the 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 heating time is, for example, 30 to 240 minutes, preferably 80 to 180 minutes, and more preferably 100 to 150 minutes.

[0198] If the resin component (B) contains a second resin, a metallic luster film may be formed during the drying process by phase separation through spinodal decomposition. When a second resin is present, drying the coating film allows for phase separation into a phase containing a large amount of silver-containing metal and a phase containing a small amount of silver-containing metal by spinodal decomposition as the solvent evaporates.

[0199] [Structure of metallic luster film] The metallic luster film obtained by the above method is formed on a substrate (decorated object) and laminated on the substrate, and contains composite nanoparticles (A) of a silver-containing metal and a protective colloid, and a resin component (B) containing a cellulose-based resin. The average thickness of the metallic luster film 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.

[0200] In particular, a metallic luster film formed on a substrate and containing a second resin may have a structure in which an interface layer, an intermediate layer, and a surface layer are sequentially laminated on the substrate.

[0201] The interface layer is formed of the composite nanoparticles, and the composite nanoparticles are arranged or oriented at the interface with the substrate to form a dense thin film of silver-containing metal (silver-containing metal thin film). By forming such an interface layer at the interface with the substrate, the metallic luster from the back surface can be improved in the case of transparent substrates.

[0202] The average thickness of the interface layer is, for example, 5 to 300 nm, preferably 10 to 200 nm, more preferably 10 to 100 nm, and more preferably 20 to 40 nm.

[0203] In this application, the average thickness of the interface layer can be measured by observing the cross-section of the silver-lustered film with a transmission electron microscope (TEM).

[0204] The intermediate layer has a phase-separated structure comprising a first phase containing the composite nanoparticles and a first resin, and a second phase containing the composite nanoparticles and a second resin, with different proportions of silver-containing metal. By having a phase-separated structure with different concentrations of silver-containing metal, metallic luster can be improved even when the proportion of resin components is increased, and metallic luster, adhesion, and abrasion resistance can be achieved simultaneously.

[0205] The ratio of the first phase to the second phase (area ratio in cross-section) is first phase / second phase = 90 / 10 to 10 / 90, preferably 70 / 30 to 30 / 70, more preferably 60 / 40 to 40 / 60, and more preferably 55 / 45 to 45 / 55.

[0206] In this application, the ratio can be measured based on a transmission electron microscope (TEM) image of a cross-section of the silver-gloss film.

[0207] The phase separation structure may be a sea-island structure or a co-continuous structure. Of these, the sea-island structure is preferred. When the intermediate layer is a sea-island structure, the continuous phase (matrix phase) constituting the sea portion may be the first phase or the second phase.

[0208] In a sea-island structure, the average diameter of the dispersed phase is, for example, 10 to 3,000 nm, preferably 100 to 1,000 nm, more preferably 150 to 500 nm, and more preferably 200 to 300 nm.

[0209] The average pitch of the dispersed phase (the average distance between the centers of adjacent dispersed phases) is, for example, 10 to 2,000 nm, preferably 100 to 1,000 nm, more preferably 200 to 700 nm, and more preferably 300 to 500 nm.

[0210] The method for observing the cross-section of a metallic luster film is not particularly limited, and any method commonly used for structural analysis can be used. Observation methods include morphological and structural observation using a transmission electron microscope (TEM), scanning electron microscope (SEM), electron beam microanalyzer (EPMA), scanning probe microscope (SPM), etc.; and analysis of constituent elements using fluorescent X-rays, energy-dispersive X-ray spectroscopy (EDX), wavelength-dispersive X-ray spectroscopy (WDX), electron energy-loss spectroscopy (EELS), etc. Of these, TEM observation is particularly preferred because it allows observation of the fine structure. The sample to be used for observation can be appropriately processed to suit observation and analysis; for example, a thin section sample may be prepared using a microtome.

[0211] Therefore, in this application, the structure, size, and distribution of island structures in the cross-section of the metallic luster film can be observed and measured based on the TEM image of the silver luster film cross-section, and the size is the average value of any 10 locations. Furthermore, in the TEM image, silver-containing metal nanoparticles are dark in color and can be easily identified, and in the intermediate layer, the aggregated portions of silver-containing metal nanoparticles are dispersed as the dispersed phase.

[0212] The average thickness of the intermediate layer is, for example, 0.01 to 100 μm, preferably 0.05 to 30 μm, more preferably 0.1 to 10 μm, and more preferably 0.2 to 1 μm.

[0213] The average thickness of the intermediate layer may be more than twice the average thickness of the surface layer, for example, 2 to 1,000 times, preferably 3 to 100 times, more preferably 3.5 to 50 times, and more preferably 4 to 10 times.

[0214] In this application, the average thickness of the intermediate layer can be measured by observing the cross-section of the metallic luster film with a transmission electron microscope (TEM), and is the average value of any three locations.

[0215] The surface layer is formed of the composite nanoparticles, and the composite nanoparticles are arranged or oriented on the surface of the metallic luster film to form a dense thin film (metallic thin film) of silver-containing metal. In the present invention, the metallic luster can be improved by forming such a surface layer on the surface of the metallic luster film.

[0216] The average thickness of the surface layer is, for example, 3 to 300 nm, preferably 5 to 200 nm, more preferably 10 to 150 nm, and more preferably 30 to 100 nm.

[0217] In this application, the average thickness of the surface layer can be measured by observing the cross-section of the silver-lustered film with a transmission electron microscope (TEM), and in detail, it can be measured by the method described in the examples below. [Examples]

[0218] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. In the following examples, the method for preparing the ink composition and the measurement method for evaluation tests are shown below.

[0219] [Materials used] (First resin) Cellulose ester A: Cellulose acetate butyrate "CAB-553-0.4" sold by Tomoe Engineering Co., Ltd., 2% by mass of acetyl groups, 46% by mass of butyryl groups, 4.8% by mass of hydroxyl groups, falling ball speed of 0.30 seconds according to ASTM D1343, glass transition temperature of 136°C, number average molecular weight of 20,000. Cellulose ester B: Cellulose acetate propionate "CAP-482-20" sold by Tomoe Engineering Co., Ltd., acetyl group 2.5% by mass, propionyl group 46% by mass, hydroxyl group 1.8% by mass, falling ball speed 20.0 seconds according to ASTM D1343, glass transition temperature 147°C, number average molecular weight 75,000. Cellulose ether: Ethyl cellulose "STD-100" sold by Nisshin Kasei Co., Ltd., ethoxy group content 48.0-49.5% by mass, moisture content 2.0% by mass or less, chloride content 0.15% by mass or less, viscosity 90.0-110.0 mPa·s (5% by mass solution, 25℃, toluene / ethanol = 80 / 20 (mass ratio)), glass transition temperature 129-133℃, number average molecular weight 63,420

[0220] (Second resin) Acrylic resin A: "Dianal BR-116" manufactured by Mitsubishi Chemical Corporation, acid value 7.8 mg KOH / g, glass transition temperature 48°C Acrylic resin B: "WXU-880" manufactured by DIC Corporation, isocyanate-curing acrylic resin, non-volatile content 50%, hydroxyl value 10 mg KOH / g, glass transition temperature 90°C Silicone resin: KR-255, manufactured by Shin-Etsu Chemical Co., Ltd., methylphenyl-based silicone resin, 50% non-volatile content. Epoxy resin: "jER1055" manufactured by Mitsubishi Chemical Corporation, bisphenol A type epoxy resin, epoxy equivalent weight 850, softening point 93°C, number average molecular weight 1600 Alkyd resin: DIC Corporation "D-128-65BA", isocyanate-cured alkyd resin, non-volatile content 65%, hydroxyl value 90 mgKOH / g, acid value 5.0 mgKOH / g

[0221] (Surface modifier) Surface modifier A: Surface modifier "BYK-3440" manufactured by BYChemie Japan Co., Ltd., acrylic copolymer (main component), dipropylene glycol monomethyl ether (main solvent), non-volatile content 10% Surface modifier B: Surface modifier "BYK-370" manufactured by BYChemie Japan Co., Ltd., polyester-modified polydimethylsiloxane solution containing hydroxyl groups (main component), xylene (main solvent), non-volatile content 25%

[0222] (solvent) 3-Methoxy-3-methyl-1-butanol: "Solfit" manufactured by Kuraray Co., Ltd., boiling point 174°C

[0223] (Polymer dispersant) Carboxyl group-containing polymer dispersant A: "DISPERBYK-190" manufactured by Bic Chemie, solution of carboxyl group-containing high molecular weight block copolymer, solvent: water, non-volatile component 40%, acid value 10 mg KOH / g, amine value 0 Carboxyl group-containing polymer dispersant B: "DISPERBYK-2015" manufactured by Bic Chemie, solution of carboxyl group-containing acrylic copolymer, solvent: water, non-volatile component 40%, acid value 10 mg KOH / g, amine value 0

[0224] [Glossiness] For the silver glossy films formed with the ink compositions of the examples and comparative examples, the glossiness (L value) was calculated from the intensity of reflected light in the wavelength range of 380 to 780 nm using an ultraviolet-visible-near-infrared spectrophotometer (Shimadzu Corporation "UV-3100PC") and an integrating sphere ISR-3100, and evaluated according to the following criteria. An aluminum vapor-deposited mirror with a glossiness of 100.0 (Shimadzu Corporation "Part No.: 202-35988") was used as the standard sample.

[0225] Grade A: Glossiness level of 65 or higher (Pass) Grade B: Glossiness between 60 and 65 (Pass) Grade C: Glossiness between 50 and 60 (Pass) Grade D: Glossiness less than 50 (Fail)

[0226] [Light opacity] The 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 integrated value of transmittance relative to the integrated value of blank measurement (atmosphere) was obtained by integrating the transmittance in the wavelength range of 380 to 780 nm, and evaluated according to the following criteria. A smaller integrated value of transmittance relative to the blank measurement indicates lower permeability of the film, which is preferable.

[0227] Judgment a: The integrated value of transmittance is 1.0% or less (accepted) Judgment b: The integrated value of transmittance is 5.0% or less (accepted) Judgment c: The integrated value of transmittance is greater than 5.0% (rejected)

[0228] [Adhesion] Cellotape (registered trademark) was applied to the cured film and peeled off vigorously, and evaluation was performed according to the following criteria.

[0229] Judgment a: No peeling of the film (accepted) Judgment b: Slight peeling occurs on the surface of the film, but the substrate is not visible (accepted) Judgment c: Peeling occurs on the film (rejected)

[0230] [Abrasion Resistance] A friction test was performed on the cured film using a friction and abrasion tester with dry cotton under a load of 500 g for 10 reciprocations. The 20° glossiness of the cured film after the friction test was measured, the reduction rate of glossiness before and after the friction test was obtained, and abrasion resistance was evaluated according to the following criteria.

[0231] Judgment a: The reduction rate of glossiness is less than 20% (accepted) Judgment b: The reduction rate of glossiness is 20% or more and less than 50% (accepted) Judgment c: The reduction rate of glossiness is 50% or more (rejected)

[0232] [Comprehensive Judgment] Based on the results of glossiness, light opacity, adhesion and abrasion resistance, superiority and inferiority judgment was performed, and ranks A, B and C were regarded as accepted.

[0233] Rank A: when all of glossiness, light opacity, adhesion and scratch resistance are rated a Rank B: when glossiness is rated a, no other evaluation items are rated c but one item is rated b; or when glossiness is rated b, and all other evaluation items are acceptable (rated a or rated b) Rank C: when glossiness is rated a, no other evaluation items are rated c but two or more items are rated b; or when glossiness is rated c, and all other evaluation items are acceptable (rated a or rated b) Rank D: when glossiness is rated d, or any of the other evaluation items is rated c

[0234] [Cross-sectional observation of film] A sample was cut out from the obtained silver glossy film, embedded in epoxy resin which is a general-purpose embedding resin, and a cut cross-section was exposed with a microtome, followed by SEM observation. Further, for fine structure observation, after exposing the cut cross-section with a microtome, an ultrathin section with a thickness of about 100 nm or less was prepared, subjected to TEM observation, and the size (average diameter and average pitch) of dispersed phases was measured by the following method.

[0235] (Average thickness of surface layer and interface layer) In TEM magnified images of the vicinity of the surface and the vicinity of the interface, the thickness of the layer where silver nanoparticles are arranged was measured. The average value of the layer thicknesses measured at any three locations was taken as the average thickness.

[0236] (Average diameter of dispersed phases) The major axis and minor axis of a dispersed phase (island) where silver nanoparticles are aggregated were measured, and the average value thereof was taken as the diameter of the dispersed phase (island). The average value of the diameters calculated for any 10 dispersed phases (islands) was taken as the average diameter of the dispersed phases.

[0237] (Average pitch of dispersed phases) The intersection of the major axis and minor axis of a dispersed phase was taken as the center of the dispersed phase, and the distance between the centers of adjacent dispersed phases was measured. The average value of the inter-center distances measured at any 10 locations was taken as the average pitch of the dispersed phases.

[0238] Examples 1-11 and Comparative Examples 1-3 (Method for preparing composite nanoparticle dispersion A) 66.8 g of silver nitrate and 7.2 g of polymer dispersant A containing carboxyl groups were added to 100 g of deionized 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 as not to exceed 50°C, and then heated and stirred in a water bath at 50°C for 4 hours to obtain a composite nanoparticle dispersion.

[0239] An excess amount of methanol was added to the obtained composite nanoparticle dispersion and stirred. The composite nanoparticles were then settled by centrifugation, and the supernatant was removed. Methanol was added again and stirred, and the composite nanoparticles were then settled by centrifugation, and the supernatant was removed. Diethylene glycol monobutyl ether was added to the methanol solution containing the precipitate, and the contaminating methanol was removed using an evaporator to obtain composite nanoparticle dispersion A with a silver content of 70% by mass. The particle size of the silver nanoparticles constituting the composite nanoparticles in this dispersion was confirmed using a transmission electron microscope (manufactured by JEOL Ltd.), and the number-average particle diameter of the primary particles was found to be approximately 20 nm.

[0240] (Method for preparing composite nanoparticle dispersion B) Composite nanoparticle dispersion B was prepared in the same manner as composite nanoparticle dispersion A, except that polymer dispersant B, which has carboxyl groups, was used instead of polymer dispersant A, which has carboxyl groups. When the particle size of the obtained composite nanoparticle dispersion B was confirmed using a transmission electron microscope (manufactured by JEOL Ltd.), the number-average particle diameter of the primary particles was found to be approximately 30 nm.

[0241] (Method for preparing composite nanoparticle dispersion C) 65.58 g of silver nitrate and 7.2 g of polymer dispersant A containing carboxyl groups were added to 100 g of deionized water and vigorously stirred to obtain suspension A.

[0242] 1.40 g of copper(II) nitrate trihydrate and 2.93 g of 1 mol / L nitric acid aqueous solution were taken and stirred in a 50°C water bath to dissolve the copper(II) nitrate trihydrate and obtain aqueous solution B.

[0243] The suspension A and the aqueous solution B were mixed while stirring to obtain a mixture of polymer dispersant A having a carboxyl group, silver nitrate, and copper nitrate.

[0244] To this mixture, 100g of dimethylaminoethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was gradually added so that the water temperature would not exceed 50°C, and then the mixture was heated and stirred in a water bath at 50°C for 4 hours.

[0245] An excess amount of methanol was added to the obtained composite nanoparticle-containing dispersion and stirred. The silver / copper alloy nanoparticles were then settled by centrifugation, and the supernatant was removed. Methanol was added again and stirred, and the composite nanoparticles were then settled by centrifugation, and the supernatant was removed. Diethylene glycol monobutyl ether was added to the methanol solution containing the obtained precipitate, and the contaminating methanol was removed using an evaporator to obtain composite nanoparticle dispersion C, in which the ratio of copper to silver was 1 part by mass and the silver / copper alloy content was 70% by mass. The particle size of the silver / copper alloy nanoparticles in this dispersion was confirmed using a transmission electron microscope (manufactured by JEOL Ltd.), and the number-average particle diameter of the primary particles was approximately 20 nm.

[0246] (Method for preparing metallic ink composition) The composite nanoparticle dispersion, resin component, surface modifier, and solvent were mixed in the proportions shown in Tables 1-5 using a stirring and defoaming device (Kurabo Industries Ltd.'s "Mazelstar") to prepare a metallic ink composition. The amounts of resin and surface modifier in Tables 1-5 are based on solid content. The metallic ink composition was applied to a glass substrate to a thickness of 20 μm using an applicator. Then, it was heated on a hot plate at 50°C for 10 minutes, followed by heating on a hot plate at 80°C for 120 minutes. The thickness of the resulting metallic gloss film (dry thickness of the coating) was approximately 2 μm.

[0247] The evaluation results of the obtained metallic luster film are shown in Tables 1 to 5.

[0248]

Table 1

[0249]

Table 2

[0250]

Table 3

[0251]

Table 4

[0252]

Table 5

[0253] The verification results of the type and amount of the resin component are shown in Table 1.

[0254] [Examples 2, 4 to 5, Comparative Examples 1 to 5] Examples 2, 4 to 5 and Comparative Examples 1 to 5 are verifications in which only one type of resin component was used, the addition amount was 6.0% by mass (the resin amount relative to silver was 30%), and the difference in the type of resin was compared.

[0255] In Comparative Example 1 where acrylic resin A was used as the resin component, although the light opacity passed, the glossiness was 45.0 (judgment d), and the overall judgment was rank D. In Comparative Example 2 where acrylic resin B was used as the resin component, Comparative Example 3 where silicone resin was used, Comparative Example 4 where epoxy resin was used, and Comparative Example 5 where alkyd resin was used, all the glossiness met the pass level (judgment c), but the light opacity failed (judgment c), so the overall judgment was rank D.

[0256] On the other hand, Example 2, which used a cellulose-based resin (cellulose ester A) as the resin component, had a gloss score of 61.4 (rated b), and all other evaluation items were rated a, resulting in a rank of B. Similarly, Example 5, which used a cellulose-based resin (cellulose ether), had a gloss score of 61.3 (rated b), and all other evaluation items were rated a, resulting in a rank of B. Example 4, which used a cellulose-based resin (cellulose ester B), had a gloss score of 56.1 (rated c), and all other evaluation items were rated a, resulting in a rank of C. By using a cellulose-based resin as the resin component, a metallic gloss film with excellent gloss, light opacity, adhesion, and scratch resistance was obtained.

[0257] Figure 1 shows a cross-sectional photograph of the metallic luster film obtained in Example 2. In Figure 1, the lower side of the TEM image is the interface layer with the substrate, and the upper side is the surface layer. In the silver luster film of Example 2, which had high gloss, the film interior (intermediate layer) was phase-separated into regions where silver nanoparticles were aggregated (dispersed phase) and regions where silver nanoparticle aggregation was less pronounced (continuous phase). That is, the silver nanoparticles had a structure in which they were unevenly distributed in the dispersed phase. Furthermore, at the surface and the interface with the substrate, the silver nanoparticles were aligned to form a thin continuous layer (thin-walled layer).

[0258] In Example 2, the average thickness of the surface layer and interface layer was measured to be 29 nm, and the average thickness of the interface layer was 28 nm. In addition, the average diameter and average pitch of the dispersed phase (region where silver nanoparticles aggregated) were measured to be 115 nm and 149 nm, respectively.

[0259] Figure 2 shows a cross-sectional image of the metallic luster film obtained in Comparative Example 2. In Figure 2, the lower side of the TEM image is the interface layer with the substrate, and the upper side is the surface layer. In the silver luster film with low gloss, silver nanoparticles were uniformly dispersed throughout the entire film.

[0260] [Examples 1 and 3] Examples 1 and 3 are examples in which the amount of resin was varied, based on the composition of Example 2, in which the amount of resin relative to silver nanoparticles (silver) was 30%. In Example 1, where the amount of resin relative to silver was 10%, the glossiness increased to 77.2 (grade A), resulting in a rank A. In Example 3, where the amount of resin relative to silver was 50%, the glossiness was 51.3 (grade C), resulting in a rank C.

[0261] In Comparative Example 6, which contained no resin components at all, the gloss and light opacity met acceptable standards, but the adhesion and abrasion resistance failed (rank D).

[0262] Table 2 shows the verification results when a cellulose-based resin and a second resin are combined as resin components.

[0263] [Examples 6-10] Examples 6 to 10 are compositions that combine a second resin with the resin component, while maintaining the total amount of resin component added at 6.0% by mass (30% of the amount of resin relative to silver), compared to Example 2, which used only a cellulose-based resin (cellulose ester A) as the resin component. As the second resin, acrylic resin A was used in Example 6, acrylic resin B in Example 7, silicone resin in Example 8, epoxy resin in Example 9, and alkyd resin in Example 10.

[0264] Example 6 had a gloss score of 62.9 (rated b), and all other evaluation items were rated a, resulting in a rank of B. Example 7 had a gloss score of 60.6 (rated b), and all other evaluation items were rated a, resulting in a rank of B. Example 8 had a gloss score of 63.3 (rated b), and also passed the light opacity test, resulting in a rank of B. Example 9 had a gloss score of 65.1 (rated a), and all other evaluation items were rated a, resulting in a rank of A. Example 10 had a gloss score of 53.3 (rated c), and all other evaluation items were rated a, resulting in a rank of C. Even when cellulose ester A was used in combination with the second resin, a metallic gloss film with excellent gloss, light opacity, adhesion, and abrasion resistance was obtained.

[0265] [Examples 11-13] Examples 11-13 are compositions that combine a second resin with the resin component, while maintaining the total amount of resin component added at 6.0% by mass (30% of the amount of resin relative to silver), compared to Example 4, which used only a cellulose-based resin (cellulose ester B) as the resin component. As the second resin, acrylic resin A was used in Example 11, silicone resin in Example 12, and epoxy resin in Example 13.

[0266] Example 11 had a gloss score of 50.5 (rated C) and all other evaluation items were rated A, resulting in a rank of C. Example 12 had a gloss score of 77.7 (rated A) and all other evaluation items were rated A, resulting in a rank of A. Example 13 had a gloss score of 58.9 (rated C) and all other evaluation items were rated A, resulting in a rank of C. Even when cellulose ester B was used in combination with the second resin, a metallic gloss film with excellent gloss, light opacity, adhesion, and abrasion resistance was obtained.

[0267] [Examples 14-16] Examples 14-16 are examples of compositions that combine a second resin with the resin component, while maintaining the total amount of resin component added at 6.0% by mass (30% of the amount of resin relative to silver), compared to Example 5, which used only a cellulose-based resin (cellulose ether) as the resin component. As the second resin, acrylic resin A was used in Example 14, silicone resin in Example 15, and epoxy resin in Example 16.

[0268] Example 14 had a gloss score of 63.6 (rated b), and all other evaluation items were rated a, resulting in a rank of B. Example 15 had a gloss score of 69.2 (rated a), and all other evaluation items were rated a, resulting in a rank of A. Example 16 had a gloss score of 70.3 (rated a), and all other evaluation items were rated a, resulting in a rank of A. Similar to cellulose ester, a metallic silver gloss film with excellent gloss, light opacity, adhesion, and abrasion resistance was obtained when cellulose ether was used in combination with the second resin.

[0269] Table 3 shows the results of testing when the protective colloid of the composite nanoparticles was changed, when composite nanoparticles containing a silver / copper alloy were used as the composite nanoparticles, and with or without a surface modifier.

[0270] [Examples 17-20] Examples 17-18 are examples based on Example 2, which used only a cellulose-based resin (cellulose ester A) as the resin component, with the type of composite nanoparticles changed. In Example 17, composite nanoparticle dispersion A and composite nanoparticle dispersion B with a different protective colloid were used as composite nanoparticles, and in Example 18, composite nanoparticle dispersion C containing a silver / copper alloy was used. Examples 19-20 are examples based on Example 6, which used a cellulose-based resin (cellulose ester A) and a secondary resin (acrylic resin A) as the resin components in a ratio of cellulose-based resin:secondary resin = 50:50, with the type of composite nanoparticles changed. In Example 19, composite nanoparticle dispersion A and composite nanoparticle dispersion B with a different protective colloid were used as composite nanoparticles, and in Example 20, composite nanoparticle dispersion C containing a silver / copper alloy was used.

[0271] Example 17 had a gloss score of 60.1 (rated b) and all other evaluation items were rated a, resulting in a rank of B. Example 18 had a gloss score of 57.2 (rated c) and all other evaluation items were rated a, resulting in a rank of C. Example 19 had a gloss score of 57.3 (rated c) and all other evaluation items were rated a, resulting in a rank of C. Example 20 had a gloss score of 58.3 (rated c) and all other evaluation items were rated a, resulting in a rank of C. When the protective colloid of the composite nanoparticles was changed, and when composite nanoparticles C containing a silver / copper alloy were used as the composite nanoparticles, a metallic gloss film with excellent gloss, light opacity, adhesion, and abrasion resistance was obtained.

[0272] [Examples 21-24] Examples 21-22 are examples in which a surface modifier was added to the composition of Example 2. Examples 23-24 are examples in which a surface modifier was added to the composition of Example 6. As the surface modifier, surface modifier A (acrylic surface modifier) ​​was used in Examples 21 and 23, and surface modifier B (silicone surface modifier) ​​was used in Examples 22 and 24. In Example 21, the gloss was 65.3 (rated A), and all other evaluation items were also rated A, resulting in a rank A. In Example 22, the gloss was 74.0 (rated A), and all other evaluation items were also rated A, resulting in a rank A. In Example 23, the gloss was 60.4 (rated B), and all other evaluation items were rated A, resulting in a rank B. In Example 24, the gloss was 52.7 (rated C), and all other evaluation items were rated A, resulting in a rank C. Even with the addition of a surface modifier, a metallic gloss film with excellent gloss, light opacity, adhesion, and abrasion resistance was obtained.

[0273] Table 4 shows the verification results when the amount of resin relative to silver nanoparticles was varied, compared to Example 6, in which cellulose ester A and acrylic resin A were used as resin components and their mass ratio was equal.

[0274] [Examples 25-27] All of the examples met the passing standard (ranks A to C), but as the amount of resin relative to the silver nanoparticles increased, there was a tendency for glossiness to decrease, while adhesion and abrasion resistance tended to improve. Compared to Example 6, where the amount of resin relative to the silver nanoparticles was 30% by mass, Example 26, with 10% by mass, showed an increase in glossiness to 75.5 (a rating), and all other evaluation items also received an a rating, resulting in a rank A. In contrast, Example 25, with 5% by mass, showed a further increase in glossiness to 77.1 (a rating), but adhesion and abrasion resistance decreased (b rating), resulting in a rank C. On the other hand, in Example 27, with 50% by mass of resin relative to the silver nanoparticles, the glossiness decreased to 50.3 (c rating), but all other evaluation items received an a rating, resulting in a rank C.

[0275] Table 5 shows the verification results when the mass ratio of cellulose ester resin A to the second resin (acrylic resin A) was varied while keeping the amount of resin relative to the silver nanoparticles equal (30% by mass), compared to Example 2, which used only cellulose ester resin A as the resin component.

[0276] [Examples 28-29] In Example 2, which did not use acrylic resin A (cellulose ester A:acrylic resin A = 100:0), in Example 28, which contained a small amount of the second resin (cellulose ester resin A:acrylic resin A = 90:10), and in Example 6, which used equal amounts of both (cellulose ester resin A:acrylic resin A = 50:50), the gloss level was rated as b. However, in Example 29, which increased the proportion of the second resin (cellulose ester resin A:acrylic resin A = 10:90), the gloss level decreased to 50.1 (rated as c), resulting in a rank of C. In Comparative Example 1, which used only acrylic resin A without cellulose ester A (cellulose ester A:acrylic resin A = 0:100), the gloss level was unacceptable (rated as d), resulting in an overall rank of D. [Industrial applicability]

[0277] The ink composition of the present invention can be used to improve the decorative properties of various objects to be decorated (molded bodies), and can be used for decorative and painting purposes, as well as for inkjet printing applications, such as for interior and exterior parts of automobiles, emblems, mobile phones, laptop computers, golf club shafts, flexible packaging, and cosmetic containers.

Claims

1. An ink composition for improving the decorative properties of an object to be decorated, comprising composite nanoparticles (A) of a silver-containing metal and a protective colloid, and a resin component (B) comprising a cellulose resin and a second resin, and substantially free of a polyvinyl acetal resin, The second resin is at least one selected from the group consisting of polyester resins, (meth)acrylic resins, epoxy resins, and silicone resins. The mass ratio of the cellulose resin to the second resin is former / latter = 93 / 7 to 45 / 55, and An ink composition in which the proportion of the resin component (B) is 20 to 40 parts by mass per 100 parts by mass of the silver-containing metal of the composite nanoparticles (A).

2. The ink composition according to claim 1, wherein the cellulose-based resin is at least one selected from the group consisting of cellulose esters, cellulose ethers, and cellulose ether esters.

3. The ink composition according to claim 1 or 2, further comprising a surface modifier (C).

4. The ink composition according to claim 3, wherein the proportion of the surface modifier (C) is 0.1 to 30 parts by mass per 100 parts by mass of the silver-containing metal of the composite nanoparticles (A).

5. The ink composition according to claim 1 or 2, further comprising a solvent (D), wherein the solvent (D) comprises at least one selected from the group consisting of alkylene glycol monoalkyl ethers and dialkylene glycol monoalkyl ethers.

6. A method for producing a metallic luster film, comprising a coating step of applying an ink composition according to claim 1 or 2 onto a substrate, and a drying step of drying the coating film formed with the ink composition to obtain a metallic luster film.

7. A metallic luster film for improving the decorative properties of an object to be decorated, comprising composite nanoparticles (A) of a silver-containing metal and a protective colloid, and a resin component (B) comprising a cellulose-based resin and a second resin, The second resin is at least one selected from the group consisting of polyester resins, (meth)acrylic resins, epoxy resins, and silicone resins. The mass ratio of the cellulose resin to the second resin is former / latter = 93 / 7 to 45 / 55, and A metallic luster film in which the proportion of the resin component (B) is 20 to 40 parts by mass per 100 parts by mass of the silver-containing metal composite nanoparticle (A).

8. A decorative body comprising a substrate which is a body to be decorated, and a metallic luster film according to claim 7 which is laminated on the substrate.

9. A method for decorating a substrate, which is a substrate to be decorated, by laminating the metallic luster film described in claim 7 onto the substrate.

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