Silver gloss film and its manufacturing method and use

Abstract

To provide a silver gloss film that has high gloss (regular reflectivity of light) and excellent resistance to discoloration while maintaining a color tone close to silvery white, even without providing a topcoat layer. The silver gloss film, which contains a sintered body of composite nanoparticles of silver-containing metal nanoparticles and a protective colloid and has an average thickness of 25 to 200 nm, is laminated on an object to be decorated, imparting a silver gloss to the object. This silver gloss film has an irradiance of 120 W / m 2 The color difference ΔE before and after a weather resistance test at a black panel temperature of 63° C. and an irradiation time of 640 hours may be 5 or less. * is 90 or more, and chromaticity a * and chromaticity b * may be -6 to 6. The proportion of the silver-containing metal nanoparticles in the glossy silver film may be 90 mass % or more. An undercoat layer formed of a cured product of a curable composition containing at least one resin selected from the group consisting of a (meth)acrylic resin and an epoxy resin may be interposed between the object to be decorated and the glossy silver film.

Description

[Technical Field]

[0001] The present invention relates to a silver gloss film for metallic decoration of various objects to be decorated, as well as a method for producing the same and uses thereof. [Background technology]

[0002] Metallic decoration is required in a wide range of fields, such as automotive interior and exterior parts, emblems, electronic devices, cosmetic containers, and golf club shafts, and a high level of metallic luster comparable to that of metal is required to achieve a luxurious feel. In particular, silver has a high light reflectivity and therefore a beautiful metallic luster (metallicity, brilliance, and specularity), and is expected to be a metal suitable for advanced design. As a method for forming a silver gloss film, a method using an ink containing silver nanoparticles is known because of its excellent metallic luster. JP 2022-008104 A (Patent Document 1) discloses a method for forming a silver gloss film using an ink that has excellent silver gloss, adhesion, and abrasion resistance.

[0003] On the other hand, when such inks are used as decorative coatings for the interior and exterior of automobiles or containers, the color characteristics of the coating film are also important, and they are also required to exhibit little discoloration during use and excellent weather resistance.

[0004] Japanese Patent Laid-Open Publication No. 2018-114747 (Patent Document 2) and Japanese Patent Laid-Open Publication No. 2019-031086 (Patent Document 3) disclose a surface decorative structure that has a silver mirror film layer that has good gloss and corrosion resistance, and state that corrosion resistance, weather resistance, adhesion, and long-term brilliance can be improved by adding a combination of a specific ultraviolet absorber and a specific light stabilizer, or a specific rust inhibitor, to at least one of the primer coating film and top coating film that are laminated on both sides of the silver mirror film layer.

[0005] Japanese Patent Laid-Open Publication No. 2007-169685 (Patent Document 4) discloses a metal plated material having a silver mirror layer, and describes that the corrosion resistance of the silver mirror layer can be improved by adding a benzotriazole compound to at least one of an undercoat layer and a topcoat layer laminated on both sides of the silver mirror layer.

[0006] Japanese Patent Application Laid-Open No. 2014-191171 (Patent Document 5) describes a film mirror with excellent crack resistance and light resistance in the barrier layer, which has a resin substrate, a metal reflective layer made of silver, and an organic barrier layer made of a constituent material having an epoxy group or an isocyanate group, and the oxygen permeability of the organic barrier layer is 10 ml / m 2 A film mirror with a viscosity of 1 / day / atm or less is disclosed. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2022-008104 [Patent Document 2] Japanese Patent Application Publication No. 2018-114747 [Patent Document 3] Japanese Patent Application Publication No. 2019-031086 [Patent Document 4] Japanese Patent Application Laid-Open No. 2007-169685 [Patent Document 5] Japanese Patent Application Laid-Open No. 2014-191171 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the silver gloss films of Patent Documents 2 to 5 have their weather resistance enhanced by laminating some kind of topcoat layer on the silver layer, which increases the labor and cost of the lamination work. Furthermore, although Patent Documents 2 to 5 describe weather resistance, they do not specifically describe discoloration resistance, and do not evaluate the color of the silver gloss film.

[0009] In addition, the evaluation of color characteristics is carried out using L * a * b * Evaluation by color space is generally used, and L * represents brightness (the larger the value, the brighter the light), and a * represents the red to green hue (more positive values ​​indicate more reddish and more negative values ​​indicate more greenish), and b * represents a yellow to blue hue (the larger the positive value, the stronger the yellow tone, and the larger the negative value, the stronger the blue tone). In other words, bright silvery white, which is the color that expresses a vivid silver gloss film, is L * is large, and a * and b * It can be said that this color is close to zero. * a * b * In the color system, when comparing two colors, an index called color difference (ΔE) is used. Color difference (ΔE) is the difference in lightness (ΔL * ) and chromaticity difference (Δa * and Δb * ) is expressed by the following formula:

[0010] ΔE=[(ΔL * ) 2 +(Δa * ) 2 +(Δb * ) 2 ] 1 / 2

[0011] In particular, when using ink as a decorative paint, it is important that discoloration due to sunlight or other light is minimal. * ) and chromaticity difference (Δa * and Δb * ) and the color difference (ΔE), which is evaluated by taking both factors into account, are required to be small even after use.

[0012] A common method for evaluating discoloration due to light is to evaluate the color difference (ΔE) before and after a weather resistance test using a xenon weather meter. A xenon weather meter is a testing device that irradiates a sample with a xenon lamp, a light source that resembles sunlight. By increasing the illuminance of the irradiated light and accelerating deterioration, discoloration due to use can be reproduced in a short period of time. This weather resistance test is also standardized in JIS K 5600-7-7:2008, so it is used by many users.

[0013] For example, the silver gloss ink described in Patent Document 1 produces a silver gloss film that is excellent in silver gloss, adhesion, and abrasion resistance, but has a problem in that it does not meet the required properties of the weather resistance test by users because the color difference (ΔE) before and after the weather resistance test is large and discoloration occurs.

[0014] Therefore, the object of the present invention is to provide a glass substrate having high gloss (regular reflectivity of light) and a color tone close to silver-white (L * is large, and a * and b * The present invention provides a glossy silver film that is excellent in resistance to discoloration (small color difference ΔE) before and after weather resistance testing while ensuring a color difference ΔE close to zero, as well as a method for producing the same and uses thereof. [Means for solving the problem]

[0015] As a result of extensive research to achieve the above object, the present inventors have discovered that by adjusting the average thickness of a silver gloss film containing a sintered body of silver-containing metal nanoparticles to 25 to 200 nm, it is possible to improve the discoloration resistance of the silver gloss film while maintaining high gloss (regular reflectivity of light) and a color close to silver-white, even without providing a topcoat layer, and have completed the present invention.

[0016] That is, the present invention includes the following aspects.

[0017] Aspect [1]: A silver glossy film containing a sintered body of silver-containing metal nanoparticles and having an average thickness of 25 to 200 nm.

[0018] Aspect [2]: Irradiance 120W / m2 The silver glossy film according to the above aspect [1], wherein the color difference ΔE before and after a weather resistance test conducted at a black panel temperature of 63° C. for 640 hours is 5 or less.

[0019] Aspect [3]: Lightness L * is 90 or more, and chromaticity a * and chromaticity b * The silver glossy film according to the above aspect [1] or [2], wherein each of

[0020] Aspect [4]: ​​The glossy silver film according to any one of Aspects [1] to [3], wherein the proportion of the silver-containing metal nanoparticles in the glossy silver film is 90 mass % or more.

[0021] Aspect [5]: The silver glossy film according to any one of Aspects [1] to [4], wherein the silver-containing metal nanoparticles are silver nanoparticles.

[0022] Aspect [6]: The silver glossy film according to any one of Aspects [1] to [5], wherein the proportion of the resin component is 20 parts by mass or less per 100 parts by mass of the silver-containing metal nanoparticles.

[0023] Aspect [7]: A decorative body comprising an object to be decorated and the silver gloss film according to any one of aspects [1] to [6] laminated on the object to be decorated.

[0024] Aspect [8]: The decorative body according to aspect [7], wherein an undercoat layer is interposed between the object to be decorated and the silver gloss film.

[0025] Aspect [9]: A decorative body according to aspect [8], wherein the undercoat layer is formed from a cured product of a curable composition containing at least one resin selected from the group consisting of (meth)acrylic resins and epoxy resins.

[0026] Aspect

[10] : The decorative body according to aspect [7] or [8], wherein the silver gloss film is the outermost surface layer.

[0027] Aspect

[11] : A method for producing a decorative body according to any one of aspects [7] to

[10] , comprising a coating step of applying a liquid composition containing composite nanoparticles of silver-containing metal nanoparticles and a protective colloid onto an object to be decorated to form a coating film, and a heating step of heating the coating film at a temperature of 130°C or higher to obtain a glossy silver film.

[0028] Aspect

[12] : The method according to aspect

[11] , wherein the number average particle diameter of the silver-containing metal nanoparticles is 8 to 80 nm.

[0029] Aspect

[13] : A method for imparting a silver luster to an object to be decorated by laminating the silver luster film according to any one of aspects [1] to [6] on the object to be decorated. [Effects of the Invention]

[0030] In the present invention, the silver gloss film contains a sintered body of silver-containing metal nanoparticles and has an average thickness adjusted to 1 to 100 nm. Therefore, even without providing a topcoat layer, the film has high gloss (regular reflectivity of light), and while maintaining a color close to silver-white, it also has improved resistance to discoloration. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is a scanning electron microscope (SEM) image (100,000 magnifications) of the glossy silver film obtained in Comparative Example 1 before the weather resistance test. [Figure 2] FIG. 2 is an SEM image (100,000 times magnification) of the glossy silver film obtained in Comparative Example 1 after the weather resistance test. [Figure 3] FIG. 3 is an SEM image (100,000 magnifications) of the glossy silver film obtained in Example 3 before the weather resistance test. [Figure 4] FIG. 4 is an SEM image (100,000 magnifications) of the glossy silver film obtained in Example 3 after the weather resistance test. [Figure 5] FIG. 5 is an SEM image (100,000 magnifications) of the glossy silver film obtained in Example 4 before the weather resistance test. [Figure 6] FIG. 6 is an SEM image (100,000 magnifications) of the glossy silver film obtained in Example 4 after the weather resistance test. DETAILED DESCRIPTION OF THE INVENTION

[0032] [Silver gloss film] The glossy silver film of the present invention is formed from a sintered body of silver-containing metal nanoparticles (the silver-containing metal nanoparticles are melted by heating and adjacent particles are solidified together), and has excellent tarnish resistance. In contrast, in the glossy silver film of Patent Document 1, which is a conventional technology, the silver nanoparticles (silver-containing composite nanoparticles) are simply dried, and adjacent silver nanoparticles are not solidified together (do not form a sintered body), so their tarnish resistance is insufficient. The reason why the glossy silver film of the present invention has superior tarnish resistance to the glossy silver film of Patent Document 1 can be presumed as follows. That is, in the present invention, the movement of silver-containing metal nanoparticles that are solidified with adjacent silver-containing metal nanoparticles is restricted (the raw material nanoparticles solidify together, forming large particles and losing their shape), whereas in Patent Document 1, the unsolidified silver nanoparticles are easily mobile. Therefore, even when exposed to sunlight containing ultraviolet rays outdoors for a long period of time, the sintered body of silver-containing metal nanoparticles in the present invention does not change (the arrangement of large particles in the film does not change), whereas in Patent Document 1, the unconsolidated silver nanoparticles move and aggregate (the arrangement of silver nanoparticles in the film changes), which is presumably why the glossy silver film discolors.

[0033] The silver gloss film of the present invention has excellent resistance to discoloration, so the color difference ΔE before and after the weather resistance test is small, and the irradiance is 120 W / m 2 The color difference ΔE before and after a weather resistance test conducted at a black panel temperature of 63°C and an irradiation time of 640 hours may be 5 or less, preferably 4 or less, further preferably 3 or less, even more preferably 2 or less, and most preferably 1.5 or less, and may be, for example, 0.1 to 5 (particularly 0.5 to 4).

[0034] In the present application, the color difference ΔE can be measured in detail by the method described in the examples below.

[0035] The glossy silver film of the present invention is thin, with an average thickness of 25 to 200 nm, resulting in high specular reflectivity and improved gloss. Adjusting the average thickness of the glossy silver film to the above range means that it is substantially free of resin components. For example, if a resin component is included, a phase-separated structure (a phase-separated structure between a silver layer in which silver nanoparticles are arranged and a resin layer) as described in Patent Document 1 will be formed, making it difficult to adjust to such a thin film. A glossy silver film with such an average thickness can be prepared by adjusting the thickness to correspond to the thickness of the "silver layer" alone in the surface or interface layer of the glossy silver film of Patent Document 1, reducing the particle size of the silver-containing metal nanoparticles to minimize the film thickness, and further agglomerating the individual nanoparticles.

[0036] The average thickness of the glossy silver film may be in the range of 25 to 200 nm (for example, 30 to 180 nm, particularly 30 to 95 nm), preferably 70 to 170 nm, further preferably 80 to 150 nm, even more preferably 85 to 130 nm, and most preferably 90 to 120 nm. If the average thickness of the glossy silver film is less than 25 nm, the glossy silver film will be too thin and have high light transmittance (weak coloring), which may make it difficult to distinguish the coloring as silver decoration. If the thickness exceeds 200 nm, the smoothness of the surface of the sintered body will decrease, impairing the regular reflectivity of light and reducing the gloss.

[0037] In the present application, the average thickness of the glossy silver film can be measured using an SEM, and more specifically, can be measured by the method described in the examples below.

[0038] The silver gloss film of the present invention is formed from a sintered body of nanometer-sized particles called silver-containing metal nanoparticles, and therefore has a color close to silver-white, and a brightness L * is large and chromaticity a * and chromaticity b * The absolute values ​​of are all small.

[0039] For details, see Lightness L *The lightness L may be 60 or more (particularly 90 or more), for example, 85 to 100, preferably 90 to 99.9, further preferably 93 to 99.8, even more preferably 95 to 99.5, and most preferably 98 to 99. * If the value is too small, the color will be dark, which may impair the silvery white color.

[0040] chromaticity a * and chromaticity b * The chromaticity a may be in the range of -10 to 10, preferably in the range of -6 to 6, and more preferably in the range of -5 to 5. * and chromaticity b * If the value is outside this range, the silver-white color may be lost (for example, * If is too positive, the color may be too yellow.

[0041] In this application, the lightness L * , chromaticity a * and chromaticity b * Specifically, it can be measured by the method described in the Examples below.

[0042] The silver gloss film of the present invention has excellent resistance to discoloration, and even after weather resistance testing, the brightness L * is large and chromaticity a * and chromaticity b * The absolute values ​​of are all small.

[0043] For details, see the brightness L after weather resistance test. * The lightness L may be 60 or more (particularly 90 or more), for example, 90 to 100, preferably 92 to 99.9, further preferably 93 to 99.8, even more preferably 95 to 99.5, and most preferably 98 to 99. * If the value is too small, the color will be dark, which may impair the silvery white color.

[0044] Color a after weather resistance test * and chromaticity b * The chromaticity a may be in the range of -10 to 10, preferably in the range of -7 to 7, and more preferably in the range of -6 to 6. *and chromaticity b * If the value is outside this range, the silver-white color may be lost (for example, * If is too positive, the color may be too yellow.

[0045] In this application, the lightness L after the weather resistance test * , chromaticity a * and chromaticity b * Specifically, it can be measured by the method described in the Examples below.

[0046] (silver-containing metal nanoparticles) Silver-containing metal nanoparticles are nanoparticles formed of a silver-containing metal (metal containing silver). The silver-containing metal may be silver alone or an alloy of silver with another metal. The other metal is not particularly limited as long as it can be alloyed with silver, and examples thereof include Cr, Mo, W, Ni, Pd, Pt, Cu, Au, Zn, In, Sn, and Pb. These other metals can be used alone or in combination of two or more. Of these other metals, Cu is preferred.

[0047] The proportion of silver in the silver-containing metal may be 50% by mass or more, for example, 90% by mass or more, preferably 95% by mass or more, further preferably 97% by mass or more, more preferably 99% by mass or more, and most preferably 100% by mass (silver alone). If the proportion of silver is too low, there is a risk that the silver gloss will decrease.

[0048] When the silver-containing metal is a combination of silver and another metal (particularly 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.

[0049] The silver-containing metal nanoparticles are in a state of being consolidated with adjacent particles in the sintered body, but are nanometer-sized particles in the raw material stage before sintering.

[0050] The number average particle diameter (number average primary particle diameter) of the silver-containing metal nanoparticles as raw material is, for example, 8 to 80 nm, preferably 10 to 70 nm, further preferably 22 to 60 nm, even more preferably 23 to 55 nm, and most preferably 25 to 50 nm (particularly 30 to 40 nm). If the number average particle diameter is too small, handling may be impaired, making it difficult to form a sintered body, while if it is too large, gloss may be reduced.

[0051] The silver-containing metal nanoparticles have the above number-average particle size and a wide particle size distribution in the range of 100 nm or less, but may contain almost no coarse particles exceeding 100 nm. Therefore, the maximum primary particle size of the silver-containing metal nanoparticles is, for example, 100 nm or less, preferably 80 nm or less, and more preferably 50 nm or less.

[0052] In the silver-containing metal nanoparticles, the proportion of particles having a primary particle diameter of 50 nm or more is, by mass, for example, 10 mass% or less (e.g., 0 to 8 mass%), preferably 5 mass% or less (e.g., 0.01 to 3 mass%), and more preferably 1 mass% or less (e.g., 0.02 to 0.5 mass%).

[0053] In the present application, the particle size and particle size distribution of silver-containing metal nanoparticles can be measured using a transmission electron microscope, and the number-average particle size is shown as the average value of any 200 particles.

[0054] The proportion of silver-containing metal nanoparticles in the glossy silver film may be 75% by mass or more (particularly 90% by mass or more), for example, 90 to 100% by mass, preferably 90 to 99.9% by mass, further preferably 91 to 99.5% by mass, more preferably 92 to 99.3% by mass, and most preferably 93 to 99% by mass (particularly 94 to 97% by mass). If the proportion of silver-containing metal nanoparticles is too low, the color and gloss may be reduced.

[0055] (protective colloid) The sintered body of silver-containing metal nanoparticles may be obtained by using silver-containing metal nanoparticles alone as a raw material, or may be obtained by using composite nanoparticles of silver-containing metal nanoparticles and organic components as raw materials. The sintered body of silver-containing metal nanoparticles obtained by using the composite nanoparticles contains an organic component in addition to the adhered silver-containing metal nanoparticles. Among these, the sintered body of silver-containing metal nanoparticles obtained by using composite nanoparticles containing a protective colloid as the organic component is preferred. Using composite nanoparticles containing a protective colloid improves handling and increases the productivity of the silver gloss film.

[0056] In the composite nanoparticles of silver-containing metal nanoparticles and protective colloid, the form of the composite between the silver-containing metal nanoparticles and protective colloid is not particularly limited, and may be a composite attached to or coordinated with the surface of the silver-containing metal nanoparticles, or a composite coating the surface of the silver-containing metal nanoparticles. Because silver-containing metal nanoparticles have high coordinating ability with protective colloids (or dispersants), a composite in which the protective colloid is coordinated to the surface of the silver-containing metal nanoparticles and coats the silver-containing metal nanoparticles may be used. When the silver-containing metal nanoparticles are composited with a protective colloid, the dispersion stability of the silver-containing metal nanoparticles can be improved.

[0057] The protective colloid may be a dispersant, and is often a non-volatile dispersant. In particular, the protective colloid preferably contains a polymer dispersant having a carboxyl group or a derivative group thereof. In this application, the carboxyl group also includes a carboxyl group in the form of an acid anhydride group.

[0058] The polymer dispersant (or polymer-type dispersant) may be any dispersant that has at least a carboxyl group and is capable of dispersing silver-containing metal nanoparticles, and may be an amphiphilic polymer dispersant (or oligomer-type dispersant).

[0059] Examples of the polymer dispersant include those commonly used to disperse colorants in the fields of paints, inks, etc. Representative polymer dispersants (amphiphilic polymer dispersants) include water-soluble or water-dispersible resins containing hydrophilic units (or hydrophilic blocks) formed from hydrophilic monomers.

[0060] Examples of the hydrophilic monomer include addition-polymerizable monomers such as carboxyl group-containing monomers (unsaturated polycarboxylic acids such as (meth)acrylic acid, maleic acid, and maleic anhydride, or acid anhydrides thereof), sulfo group-containing monomers (styrenesulfonic acid, etc.), and hydroxyl group-containing monomers (hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, vinylphenol, etc.); and condensation-polymerizable monomers such as ethylene oxide. The condensation-polymerizable monomers may form a hydrophilic unit (or block) by reaction with an active hydrogen such as a hydroxyl group (e.g., the hydroxyl group). The hydrophilic monomers may form a hydrophilic unit (or block) either alone or in combination of two or more. Preferred hydrophilic monomers are (meth)acrylic acid, maleic acid, maleic anhydride, and ethylene oxide.

[0061] The polymer dispersant only needs to have at least a carboxyl group, and may also have a functional group of the hydrophilic monomer, such as an acid group (sulfo group) or a hydroxyl group. These functional groups may be introduced into the polymer dispersant either alone or in combination.

[0062] The polymer dispersant may contain at least a hydrophilic unit (or hydrophilic block), and may be a homopolymer or copolymer of a hydrophilic monomer (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 (methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and 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, aralkyl (meth)acrylates such as benzyl (meth)acrylate and 2-phenylethyl (meth)acrylate; styrene-based monomers such as styrene, α-methylstyrene, and 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 carboxylic acid ester monomers such as vinyl acetate and vinyl butyrate; C monomers such as propylene oxide 3-6 Examples of the hydrophobic monomer include condensation polymerizable monomers such as alkylene oxides. The hydrophobic monomers may be used alone or in combination to form the hydrophobic unit.

[0063] The polymeric dispersant, which is a copolymer (e.g., a copolymer of a hydrophilic monomer and a hydrophobic monomer), may be a random copolymer, an alternating copolymer, a block copolymer (e.g., a copolymer composed of a hydrophilic block composed of a hydrophilic monomer and a hydrophobic block composed of a hydrophobic monomer), a comb copolymer (or a comb graft copolymer), or the like. The structure of the block copolymer is not particularly limited, and may be a diblock structure, a triblock structure (ABA type, BAB type), or the like. In the comb copolymer, the main chain may be formed of the hydrophilic block or the hydrophobic block, or may be formed of a hydrophilic block and a hydrophobic block. A block copolymer of a hydrophilic block and a hydrophobic block can also improve silver gloss.

[0064] As mentioned above, the hydrophilic unit can also be formed from a hydrophilic block (e.g., a polyalkylene oxide such as polyethylene oxide). The hydrophilic block (e.g., a polyalkylene oxide) and the hydrophobic block (e.g., a polyolefin block) may be bonded via a linking group such as an ester bond, an amide bond, an ether bond, or a urethane bond. These bonds may be formed, for example, by modifying a hydrophobic block (e.g., a polyolefin) with a modifying agent (e.g., an unsaturated carboxylic acid or its anhydride (e.g., maleic anhydride), a lactam or aminocarboxylic acid, a hydroxylamine, a diamine, etc.) and then introducing a hydrophilic block. Furthermore, a comb copolymer (a comb copolymer whose main chain is composed of a hydrophobic block) may be formed by reacting (or bonding) a polymer obtained from a monomer having a hydrophilic group such as a hydroxyl group or a carboxyl group (e.g., the hydroxyalkyl (meth)acrylate) with the condensation-type hydrophilic monomer (e.g., ethylene oxide).

[0065] Furthermore, the balance between hydrophilicity and hydrophobicity may be adjusted by using a hydrophilic nonionic monomer as a copolymerization component. Examples of such components include monomers or oligomers having an ethyleneoxy unit, such as 2-(2-methoxyethoxy)ethyl (meth)acrylate and polyethylene glycol mono(meth)acrylate (e.g., number average molecular weight 200 to 1,000). The balance between hydrophilicity and hydrophobicity may also be adjusted by modifying (e.g., esterifying) a hydrophilic group (e.g., a carboxyl group).

[0066] 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 (such as salts with amines or metal salts). 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 preferably used.

[0067] The acid value of the polymer dispersant having a carboxyl group may be, for example, 1 mgKOH / g or more (e.g., 2 to 100 mgKOH / g), preferably 3 mgKOH / g or more (e.g., 4 to 90 mgKOH / g), more preferably 5 mgKOH / g or more (e.g., 6 to 80 mgKOH / g), and more preferably 7 mgKOH / g or more (e.g., 8 to 50 mgKOH / g), and is usually 3 to 30 mgKOH / g (particularly 5 to 20 mgKOH / g). Note that the amine value of such a polymer dispersant may be 0 (or nearly 0).

[0068] In the polymer dispersant, the position of the functional group is not particularly limited, and may be located on the main chain, the side chain, or 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 a hydrophilic unit (for example, a functional group introduced by copolymerization of (meth)acrylic acid, maleic anhydride, ethylene oxide, etc.).

[0069] The polymer dispersants having a carboxyl group may be used alone or in combination of two or more kinds.

[0070] As the polymer dispersant, a polymer dispersant (high molecular weight pigment dispersant) described in JP-A-2004-207558 or the like may be used. 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 Solsperse series (manufactured by Avecia Corporation) such as Solsperse 13240, Solsperse 13940, Solsperse 32550, Solsperse 31845, Solsperse 24000, Solsperse 26000, Solsperse 27000, Solsperse 28000, and Solsperse 41090; DISPERBYK-160, DISPERBYK-161, DISPERBYK-162, and DI DISPERBYK series including DISPERBYK-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, DISPERBYK-2050 EFKA-46, EFKA-47, EFKA-48, EFKA-49, EFKA-1501, EFKA-1502, EFKA-4540, EFKA-4550, Polymer 100, Polymer 120, Polymer 150, Polymer 400, Polymer 401, Polymer 402, Polymer 403, Polymer 450, Polymer 451, Polymer 452, Polymer 453 [manufactured by EFKA Chemical Co., Ltd.]; Ajisper PB711, Ajisper PA111, Ajisper PB811, Ajisper Examples include the Ajisper series, such as Spar PB821 and Ajisper PW911 (manufactured by Ajinomoto Co., Inc.); the Floren series, such as Floren DOPA-158, Floren DOPA-22, Floren DOPA-17, Floren TG-700, Floren TG-720W, Floren-730W, Floren-740W, and Floren-745W (manufactured by Kyoeisha Chemical Co., Ltd.); and the Joncryl series, such as Joncryl 678, Joncryl 679, and Joncryl 62 (manufactured by Johnson Polymer Co., Ltd.).Representative polymeric dispersants include DISPERBYK-190, DISPERBYK-194, DISPERBYK-2015, and the like.

[0071] The number average molecular weight of the polymer dispersant, as measured by gel permeation chromatography (GPC), is, in terms of polystyrene, 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 even more preferably 7,000 to 20,000.

[0072] The polymer dispersant having a carboxyl group may be a polymer dispersant having no hydroxyl group.

[0073] The proportion of the protective colloid is, for example, 0.1 to 100 parts by mass (particularly 1 to 50 parts by mass) relative to 100 parts by mass of the silver-containing metal nanoparticles. The proportion of the polymer dispersant having a carboxyl group can be selected from the range of, for example, about 0.1 to 60 parts by mass (e.g., 1 to 50 parts by mass) relative to 100 parts by mass of the silver-containing metal, and is usually 2 to 40 parts by mass (e.g., 2.5 to 30 parts by mass), more preferably 3 to 25 parts by mass (particularly 5 to 20 parts by mass).

[0074] In the present application, the proportion of protective colloid in the composite nanoparticles can be measured by a conventional method, for example, thermal analysis (for example, simultaneous thermogravimetry / differential thermal analysis, etc.).

[0075] The protective colloid may contain other dispersants, if necessary, which may be inorganic compounds but are usually organic compounds. Examples of other dispersants include alkanols (C such as hexanol, octanol, decanol, dodecanol, and octadecanol). 6-20 Alkane monools), aldehydes (caprylic aldehyde, lauryl aldehyde, palmitic aldehyde, etc.) 6-20Examples of other dispersants include aliphatic aldehydes, aliphatic hydroxycarboxylic acids, higher fatty acids or salts thereof, and sulfonic acids (alkanesulfonic acids, arenesulfonic acids such as benzenesulfonic acid and toluenesulfonic acid). These other dispersants may be used alone or in combination of two or more.

[0076] 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, relative to 100 parts by mass of the polymer dispersant.

[0077] The method for producing the composite nanoparticles is not particularly limited, and can be a conventional method. For example, when the silver-containing metal is simple silver, the composite nanoparticles can be prepared by reducing a silver compound corresponding to the silver nanoparticles in a solvent in the presence of a protective colloid and a reducing agent. Specific production methods include those described in JP-A-2010-80442 and JP-A-2010-229544.

[0078] The proportion of the protective colloid in the silver glossy film may be 30% by mass or less, for example, 0 to 30% by mass, preferably 1 to 10% by mass, further preferably 2 to 8% by mass, even more preferably 3 to 7% by mass, and most preferably 4 to 6% by mass. If the proportion of the protective colloid is too high, there is a risk that the color, gloss, and discoloration resistance will decrease.

[0079] (resin component) The silver glossy film of the present invention may contain a resin component in addition to the silver-containing metal nanoparticles and protective colloid, as long as the effect of the present invention is not impaired.

[0080] Examples of the resin component include polyolefin resins, (meth)acrylic resins, styrene resins, vinyl resins, polyvinyl acetal resins, polyester resins, polyamide resins, polyurethane resins, epoxy resins, silicone resins, and cellulose resins.

[0081] The proportion of the resin component may be 20 parts by mass or less, preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 1 part by mass or less, relative to 100 parts by mass of the silver-containing metal nanoparticles. In order to improve discoloration resistance, the silver glossy film of the present invention preferably does not substantially contain a resin component (particularly, a (meth)acrylic resin, a polyvinyl acetal resin, or a silicone resin), and most preferably does not contain a resin component.

[0082] (additives) The silver gloss film of the present invention may further contain conventional additives. Examples of conventional additives include surface conditioners, plasticizers (or film-forming aids), gloss-imparting agents, metal corrosion inhibitors (rust inhibitors), stabilizers (antioxidants, light stabilizers, etc.), surfactants (anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants), dispersion stabilizers, thickeners or viscosity modifiers, humectants, thixotropic agents, leveling agents, penetrating agents, antifoaming agents, pH adjusters, chelating agents, surface tension adjusters, colorants (dyes and pigments, etc.), hue improvers, dye fixatives, bactericides, mildew inhibitors, antiseptics, and oxygen absorbers.

[0083] The total proportion of the conventional additives is 10 parts by mass or less, preferably 5 parts by mass or less, and more preferably 1 part by mass or less, per 100 parts by mass of the silver-containing metal nanoparticles.

[0084] [Decoration] The decorative body of the present invention comprises an object to be decorated and the above-described silver gloss film laminated on the object to be decorated.

[0085] (Decorated object) The shape of the object to be decorated (substrate) is not particularly limited, and examples thereof include one-dimensional shapes such as linear, fibrous, thread-like, and string-like shapes; two-dimensional shapes such as film-like, sheet-like, and plate-like shapes; three-dimensional shapes such as rod-like or column-like, block-like, cone-like, spherical, concave or convex, hollow (pipe-like or tubular), ring-like, slit-like, L-like, and U-like shapes; and shapes that are a combination of these shapes. Of these, two-dimensional shapes such as sheet-like and plate-like shapes are commonly used.

[0086] The material of the object to be decorated is not particularly limited, and examples thereof include organic materials such as synthetic resins and natural resins, and inorganic materials such as metals, glass, carbon materials, and ceramics. Among these, commonly used materials include synthetic resins such as polyolefin resins, (meth)acrylic resins, styrene resins, polycarbonate resins, polyester resins, polyamide resins, polyimide resins, polyurethane resins, and cellulose resins, and glasses such as soda glass, borosilicate glass, crown glass, barium-containing glass, strontium-containing glass, boron-containing glass, low-alkali glass, alkali-free glass, crystallized transparent glass, silica glass, quartz glass, and heat-resistant glass.

[0087] The silver gloss film can be laminated on the object to be decorated (coating the surface of the object to be decorated) to impart a silver gloss to the object to be decorated. Depending on the purpose, the silver gloss film can cover at least a partial area of ​​the surface of the object to be decorated, or it may cover the entire surface of the object to be decorated. For example, if the object to be decorated is in the form of a sheet or plate, the silver gloss film may be laminated on a partial or entire area of ​​at least one surface of the object to be decorated, or it may be laminated on a partial or entire area of ​​both surfaces of the object to be decorated.

[0088] The average thickness of the object to be decorated can be selected depending on the type of object to be decorated and is not particularly limited, but is, for example, 0.1 to 100 mm, preferably 0.5 to 10 mm, and more preferably 1 to 5 mm.

[0089] (undercoat layer) The decorative article of the present invention may include an undercoat layer between the object to be decorated and the glossy silver film in order to improve adhesion between the object to be decorated and the glossy silver film.

[0090] The undercoat layer is not particularly limited as long as it can improve the adhesion between the object to be decorated and the silver gloss film, but is often formed from a resin component such as a thermoplastic resin or a curable resin, and is preferably formed from a cured product of a curable composition containing a curable resin, and is particularly preferably formed from a cured product of a curable composition containing a curable resin and a curing agent.

[0091] Examples of the curable resin include (meth)acrylic resin, epoxy resin, phenolic resin, unsaturated polyester resin, and polyurethane resin. These curable resins can be used alone or in combination. Among these, (meth)acrylic resin and epoxy resin are preferred.

[0092] The (meth)acrylic resin is preferably a (meth)acrylic resin having a hydroxyl group. Furthermore, the (meth)acrylic resin having a hydroxyl group is preferably a (meth)acrylic resin containing a (meth)acrylic monomer having a hydroxyl group as a polymerization component. Examples of the (meth)acrylic monomer having a hydroxyl group include hydroxy C such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate. 2-10 These (meth)acrylic monomers having a hydroxyl group can be used alone or in combination of two or more. Among these, hydroxy C such as hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate are preferred. 2-4 Alkyl (meth)acrylates are preferred, and hydroxy C 2-3 Alkyl (meth)acrylates are particularly preferred.

[0093] The (meth)acrylic resin having a hydroxyl group may be a homopolymer consisting of a (meth)acrylic monomer having a hydroxyl group as a polymerization component, or may be a copolymer containing a copolymerizable monomer in addition to the (meth)acrylic monomer having a hydroxyl group. The position of the hydroxyl group is not particularly limited, and may be located in the main chain, a side chain, or both the main chain and the side chain.

[0094] The copolymerizable monomer includes (meth)acrylic monomers other than (meth)acrylic monomers having a hydroxyl group [other (meth)acrylic monomers], and addition-polymerizable monomers other than (meth)acrylic monomers (other addition-polymerizable monomers).

[0095] Other (meth)acrylic monomers include, for example, (meth)acrylic acid; (meth)acrylic acid C such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate. 1-20 Alkyl; (meth)acrylate cycloalkyl such as cyclohexyl (meth)acrylate; (meth)acrylate aryl such as phenyl (meth)acrylate; (meth)acrylate aralkyl such as benzyl (meth)acrylate, 2-phenylethyl (meth)acrylate; hydroxy C such as hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate 1-4 These (meth)acrylic monomers can be used alone or in combination of two or more. Among these, (meth)acrylic acid, (meth)acrylic acid C, etc. 1-4 Alkyl is preferred.

[0096] Other addition polymerizable monomers include, for example, styrene-based monomers such as styrene, α-methylstyrene, and vinyltoluene; 2-20 Examples of copolymerizable monomers include olefin-based monomers such as olefins (ethylene, propylene, 1-butene, isobutylene, 1-hexene, 1-octene, 1-dodecene, etc.); and addition-polymerizable monomers such as vinyl carboxylate ester-based monomers such as vinyl acetate and vinyl butyrate. These copolymerizable monomers can be used alone or in combination. Of these, styrene-based monomers such as styrene are preferred.

[0097] The molar ratio of the (meth)acrylic monomer having a hydroxyl group to the copolymerizable monomer (former / latter) is 100 / 0 to 5 / 95, preferably 95 / 5 to 10 / 90, and more preferably 90 / 10 to 30 / 70.

[0098] The (meth)acrylic resin having a hydroxyl group may contain a (meth)acrylic monomer having a hydroxyl group, and is more preferably a (meth)acrylic polyol resin having multiple hydroxyl groups [isocyanate-curing (meth)acrylic resin], and even more preferably a (meth)acrylic resin having multiple hydroxyl groups and styrene units (for example, a methyl (meth)acrylate-hydroxyalkyl (meth)acrylate-styrene copolymer).

[0099] The hydroxyl value of the (meth)acrylic resin having hydroxyl groups is, for example, 1 mgKOH / g or more (e.g., 1 to 300 mgKOH / g), preferably 2 mgKOH / g or more (e.g., 2 to 100 mgKOH / g), further preferably 3 mgKOH / g or more (e.g., 3 to 50 mgKOH / g), more preferably 5 mgKOH / g or more (e.g., 5 to 30 mgKOH / g), and most preferably 6 mgKOH / g or more (e.g., 6 to 15 mgKOH / g). If the hydroxyl value is too small, there is a risk that the adhesion between the object to be decorated and the glossy silver film will not be improved.

[0100] In the present application, the hydroxyl value of the (meth)acrylic resin having a hydroxyl group can be measured by a conventional method, for example, neutralization titration.

[0101] The acid value of the (meth)acrylic resin having a hydroxyl group is, for example, 100 mgKOH / g or less (e.g., 0.1 to 100 mgKOH / g), preferably 10 mgKOH / g or less (e.g., 0.3 to 10 mgKOH / g), further preferably 5 mgKOH / g or less (e.g., 0.5 to 5 mgKOH / g), and even more preferably 3 mgKOH / g or less (e.g., 1 to 3 mgKOH / g). If the acid value is too high, there is a risk that the adhesion between the object to be decorated and the silver gloss film will not be improved.

[0102] In the present application, the acid value of the (meth)acrylic resin can be measured by a conventional method, for example, neutralization titration.

[0103] The weight-average molecular weight of the (meth)acrylic resin having a hydroxyl group is, for example, 1,000 to 100,000, preferably 2,000 to 80,000 (e.g., 3,000 to 50,000), further preferably 5,000 to 30,000 (e.g., 10,000 to 20,000), and even more preferably 12,000 to 16,000. If the molecular weight is too small, there is a risk that the adhesion between the object to be decorated and the silver gloss film will not be improved, and conversely, if it is too high, there is a risk that film-forming properties will be reduced.

[0104] In the present application, the weight average molecular weight of the (meth)acrylic resin having a hydroxyl group is a value calculated from a chromatogram measured by gel permeation chromatography (GPC) using the molecular weight of standard polystyrene as a reference.

[0105] The glass transition temperature of the (meth)acrylic resin having a hydroxyl group is, for example, 0 to 120° C., preferably 40 to 110° C., further preferably 50 to 105° C., even more preferably 60 to 100° C., and most preferably 70 to 95° C. If the glass transition temperature is too low, there is a risk that the adhesion between the object to be decorated and the silver gloss film cannot be improved, and conversely, if it is too high, there is a risk that film formability will decrease.

[0106] The proportion of the (meth)acrylic resin having a hydroxyl group in the undercoat layer (of the solid content of the undercoat layer) may be 10% by mass or more, for example, 10 to 99% by mass, preferably 30 to 98% by mass, even more preferably 50 to 95% by mass, even more preferably 70 to 93% by mass, and most preferably 80 to 90% by mass.

[0107] In the present application, the glass transition temperature of the (meth)acrylic resin having a hydroxyl group can be measured using a differential scanning calorimeter (DSC).

[0108] The epoxy resin may be any compound having an epoxy group in the molecule, and is preferably a compound having two or more epoxy groups in the molecule. Epoxy resins include epoxy resins having a glycidyl group and epoxy resins having an alicyclic epoxy group, but epoxy resins having a glycidyl group are preferred.

[0109] Examples of epoxy resins having a glycidyl group include glycidyl ether type epoxy resins, glycidyl amine type epoxy resins, and glycidyl ester type epoxy resins.

[0110] Examples of glycidyl ether type epoxy resins include biphenyl type epoxy resins, naphthalene type epoxy resins, and bisphenol type epoxy resins (e.g., bis(hydroxyphenyl) C such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, and bisphenol AD ​​type epoxy resins). 1-10 epoxy resins having an alkane skeleton; tetrabromobisphenol A type resins; bisphenol S type epoxy resins, etc.), novolac type epoxy resins (for example, phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A novolac type epoxy resins, etc.), aliphatic type epoxy resins (for example, hydrogenated bisphenol A type epoxy resins, propylene glycol monoglycidyl ether to diglycidyl ether, pentaerythritol monoglycidyl ether to tetraglycidyl ether, etc.), monocyclic epoxy resins (for example, resorcinol glycidyl ether, etc.), heterocyclic epoxy resins (for example, triglycidyl isocyanurate having a triazine ring, hydantoin type epoxy resins having a hydantoin ring, etc.), tetrakis(glycidyloxyphenyl)ethane, etc.

[0111] The glycidyl amine type epoxy resin may be an epoxy resin derived from amines (particularly, polyamines such as aromatic polyamines), and may particularly be a reaction product of an amine (particularly, a polyamine) with epichlorohydrin. Examples of reaction products of amines and epichlorohydrin include aromatic glycidylamine-type epoxy resins (e.g., glycidyl aromatic diamines such as mono- to tetraglycidyldiaminodiphenylmethane, mono- to tetraglycidylmeta-xylylenediamine, and mono- to tetraglycidylpara-xylylenediamine; glycidylanilines such as mono- or diglycidylaniline, mono- or diglycidyltoluidine, N,N-mono- or diglycidyl-2,4,6-tribromoaniline, mono- to triglycidyl-p-aminophenol, and mono- to triglycidyl-m-aminophenol), aliphatic glycidylamine-type epoxy resins (e.g., mono- to tetraglycidyldiamines such as mono- to tetraglycidylhydrogenatedmeta-xylylenediamine (mono- to tetraglycidyl1,3-bis(aminomethyl)cyclohexane) and mono- to tetraglycidylhydrogenatedpara-xylylenediamine), and compounds in which the glycidyl group in these compounds is replaced with a 2-methylglycidyl group).

[0112] The glycidyl ester type epoxy resin may be a glycidyl ester of a carboxylic acid (particularly a polycarboxylic acid). Examples of the glycidyl ester type epoxy resin include aromatic glycidyl ester type epoxy resins (e.g., diglycidyl phthalate, diglycidyl terephthalate, dimethylglycidyl phthalate, etc.) and aliphatic glycidyl ester type epoxy resins (e.g., diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, etc.).

[0113] These epoxy resins can be used alone or in combination. Among these, epoxy resins having an aromatic skeleton are preferred, and bisphenol-type epoxy resins such as bisphenol A-type epoxy resins and bisphenol F-type epoxy resins are particularly preferred.

[0114] The epoxy equivalent of the epoxy resin is, for example, 50 to 1000 g / eq, preferably 100 to 500 g / eq, further preferably 150 to 300 g / eq, and even more preferably 180 to 200 g / eq. If the epoxy equivalent of the epoxy resin is too low, film-forming properties may be reduced, and conversely, if it is too high, adhesion between the object to be decorated and the silver gloss film may be reduced.

[0115] In the present application, the epoxy equivalent is defined as "the mass of an epoxy resin containing one equivalent of epoxy groups" and can be measured in accordance with JIS K 7236.

[0116] Examples of curing agents include conventional curing agents such as isocyanate-based curing agents, amine-based curing agents, acid and acid anhydride-based curing agents, and imidazole-based curing agents. Of these, isocyanate-based curing agents and acid and acid anhydride-based curing agents are preferred, with polyisocyanate and acid anhydride-based curing agents being particularly preferred. Isocyanate-based curing agents such as polyisocyanate are particularly effective when the third resin has functional groups (especially hydroxyl groups), and acid anhydride-based curing agents are particularly effective when the third resin is an epoxy resin.

[0117] Examples of polyisocyanates include aliphatic polyisocyanates [diisocyanates such as propylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMDI), and lysine diisocyanate (LDI); triisocyanates or polyisocyanates such as 1,6,11-undecane triisocyanate, methyl octane, and 1,3,6-hexamethylene triisocyanate], alicyclic polyisocyanates [cyclohexane 1,4-diisocyanate, isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate], and the like. diisocyanates such as isocyanates, hydrogenated bis(isocyanatophenyl)methane; tri- or polyisocyanates such as bicycloheptane triisocyanate; aromatic polyisocyanates [diisocyanates such as phenylene diisocyanate, tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), naphthalene diisocyanate (NDI), bis(isocyanatophenyl)methane (MDI), tolidine diisocyanate (TODI), 1,3-bis(isocyanatophenyl)propane; tri- or polyisocyanates].

[0118] The polyisocyanate may be a derivative such as a multimer (dimer, trimer, tetramer, etc.), an adduct, or a modified product (biuret modified product, allophanate modified product, urea modified product, etc.), or a urethane oligomer having multiple isocyanate groups. Examples of modified products or derivatives of polyisocyanate include an adduct of a polyisocyanate (e.g., an aliphatic polyisocyanate such as hexamethylene diisocyanate) with a polyhydric alcohol (e.g., trimethylolpropane, pentaerythritol), a biuret of the polyisocyanate, and a multimer of the polyisocyanate (e.g., an aliphatic polyisocyanate) (e.g., a polyisocyanate having an isocyanurate ring, such as a trimer of hexamethylene diisocyanate).

[0119] These polyisocyanates can be used alone or in combination of two or more. Among these polyisocyanates, aliphatic polyisocyanates or derivatives thereof (e.g., HDI or its trimer), aromatic polyisocyanates (TDI, MDI, etc.), etc. are commonly used.

[0120] Examples of acid anhydride curing agents include aliphatic carboxylic anhydrides such as dodecenyl succinic anhydride; alicyclic carboxylic anhydrides such as methyltetrahydrophthalic anhydride; and aromatic carboxylic anhydrides such as phthalic anhydride. These acid anhydride curing agents can be used alone or in combination. Among these, alicyclic carboxylic anhydrides such as methyltetrahydrophthalic anhydride are preferred.

[0121] The ratio of the curing agent is, for example, 1 to 300 parts by mass, preferably 5 to 200 parts by mass, and more preferably 10 to 180 parts by mass relative to 100 parts by mass of the curable resin.

[0122] When the curable resin is a (meth)acrylic resin, the proportion of the curing agent is, for example, 1 to 100 parts by mass, preferably 2 to 50 parts by mass, further preferably 3 to 30 parts by mass, more preferably 5 to 25 parts by mass, and most preferably 10 to 20 parts by mass, relative to 100 parts by mass of the (meth)acrylic resin [particularly a (meth)acrylic resin having a hydroxyl group]. If the proportion of the curing agent is too low, there is a risk that the adhesion between the object to be decorated and the glossy silver film will not be improved, and conversely, if it is too high, there is a risk that the adhesion between the object to be decorated and the glossy silver film will not be improved.

[0123] When the curable resin is an epoxy resin, the proportion of the curing agent relative to 100 parts by mass of the epoxy resin is, for example, 10 to 300 parts by mass, preferably 50 to 250 parts by mass, further preferably 100 to 200 parts by mass, and even more preferably 150 to 180 parts by mass.

[0124] The undercoat layer may further contain conventional additives in addition to the hydroxyl group-containing (meth)acrylic resin and the curing agent. Examples of the conventional additives include those exemplified as conventional additives that can be incorporated into the silver gloss film, as well as curing accelerators (e.g., imidazoles such as 1-isobutyl-2-methylimidazole).

[0125] The proportion of the curing agent is, for example, 0.1 to 10 parts by mass, preferably 1 to 5 parts by mass, and more preferably 2 to 4 parts by mass, relative to 100 parts by mass of the curable resin (particularly, epoxy resin).

[0126] The total proportion of conventional additives 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 total of the curable resin [particularly, the (meth)acrylic resin or epoxy resin having a hydroxyl group] and the curing agent.

[0127] The total proportion of the curable resin [particularly, a (meth)acrylic resin or epoxy resin having a hydroxyl group] and the curing agent in the undercoat layer (of the solid content of the undercoat layer) may be 50% by mass or more, for example, 50 to 100% by mass, preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and most preferably 100% by mass.

[0128] The average thickness of the undercoat layer is sufficient as long as it is 0.5 μm or more, for example, 0.5 to 100 μm, preferably 1 to 80 μm, particularly preferably 3 to 50 μm, even more preferably 5 to 40 μm, more preferably 10 to 30 μm, and most preferably 15 to 25 μm. If the average thickness of the undercoat layer is too thin, there is a risk that the adhesion between the object to be decorated and the silver gloss film will not be improved.

[0129] The undercoat layer may be interposed between the object to be decorated and the silver gloss film, but if the object to be decorated is sheet-shaped or plate-shaped and the silver gloss film is laminated on both sides of the object to be decorated, the undercoat layer may be laminated on one side of the object to be decorated, or on both sides of the object to be decorated.

[0130] The decorative body of the present invention may further include other functional layers in addition to the undercoat layer. For example, a top coat layer or an ultraviolet absorbing layer may be laminated on the surface of the silver gloss film as a top coat layer (protective layer). However, since the silver gloss film in the present invention has high resistance to discoloration by itself, the silver gloss film may be exposed as the outermost surface layer without laminating a top coat layer.

[0131] [Method of manufacturing decorative objects] The method for manufacturing the decorative body of the present invention is not particularly limited as long as it can form a glossy silver film on the object to be decorated. However, from the standpoint of productivity, it is preferable that the method includes a coating step in which a liquid composition containing composite nanoparticles of silver-containing metal nanoparticles and a protective colloid is applied to the object to be decorated to form a coating film, and a heating step in which the coating film is heated at a temperature of 130°C or higher to obtain a glossy silver film.

[0132] (coating process) In the coating step (coating step of a silver gloss film), the liquid composition can be prepared by mixing the composite nanoparticles and a solvent by a conventional method. A conventional stirring device can be used for the mixing, and for example, a stirring and degassing device may be used. Adding a solvent to the liquid composition can also improve film-forming properties.

[0133] The solvent (first solvent) preferably contains a polar organic solvent. Examples of the polar organic solvent include alcohols (C1, C2, C3, C4, C5, C6, C7, C8, C9, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20, C21, C22, C23, C24, C25, C36, C37, C4 1-4 Alkanols, 3-methoxy-3-methyl-1-butanol, etc.), polyhydric alcohols (alkanediols such as ethylene glycol and propylene glycol, alkanetriols such as glycerin and trimethylolpropane, alkanetetraols such as pentaerythritol, etc.), amides (acylamides such as formamide and acetamide, mono- or di-C alkyl amides such as N-methylformamide, N-methylacetamide, N,N-dimethylformamide, and N,N-dimethylacetamide) 1-4acylamides, etc.), pyrrolidones (2-pyrrolidone, 3-pyrrolidone, N-methyl-2-pyrrolidone, N-methyl-3-pyrrolidone, etc.), ketones (acetone, diacetone alcohol, methyl ethyl ketone, isophorone, etc.), ethers (dioxane, tetrahydrofuran, etc.), organic carboxylic acids (acetic acid, etc.), esters (acetic acid esters such as methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, amyl acetate, etc.), alkylene glycol monoalkyl ethers (methyl cellosolve, ethyl cellosolve, propylene glycol methyl ether, 3-methoxy-3-methyl-1-butanol, etc.) 2-6 Alkylene glycol mono C 1-4 alkyl ethers), dialkylene glycol monoalkyl ethers (di-C such as methyl carbitol, ethyl carbitol, propyl carbitol, and butyl carbitol) 2-6 Alkylene glycol mono C 1-4 alkyl ethers, etc.), cellosolve acetates (C such as ethyl cellosolve acetate) 1-4 Alkyl cellosolve acetates), carbitol acetates (methyl carbitol acetate, butyl carbitol acetate, etc.) 1-4 alkyl carbitol acetate, etc.), dimethyl sulfoxide, etc. These polar organic solvents can be used alone or in combination of two or more.

[0134] The proportion of the polar organic solvent in the solvent may be 50% by mass or more, preferably 70% by mass or more, further preferably 80% by mass or more, even more preferably 90% by mass or more, and may even be 100% by mass.

[0135] The solvent may further contain a non-polar organic solvent in addition to the polar organic solvent. Examples of non-polar organic solvents include aliphatic hydrocarbons such as hexane, octane, and decane, and alicyclic hydrocarbons such as cyclohexane and tetralin. The proportion of the non-polar organic solvent may be 50 parts by mass or less (e.g., 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.

[0136] Among these solvents, it is preferable to use one or more selected from alcohols, esters, alkylene glycol monoalkyl ethers, and dialkylene glycol monoalkyl ethers, and the aliphatic carboxylic acid C 1-6 It is more preferable that the solvent contains one or more selected from alkyl esters, alkylene glycol monoalkyl ethers, and dialkylene glycol monoalkyl ethers. Among them, the solvent is preferably a combination of alkylene glycol monoalkyl ethers and dialkylene glycol monoalkyl ethers, and C 2-6 Alkylene glycol mono C 1-3 Alkyl ether and diC 2-6 Alkylene glycol mono C 1-3 A combination with an alkyl ether is more preferred, and C 4-6 Alkylene glycol mono C 1-2 Alkyl ether and diC 2-4 Alkylene glycol mono C 1-2 A combination with an alkyl ether is most preferred.

[0137] When the solvent is a combination of an alkylene glycol monoalkyl ether and a dialkylene glycol monoalkyl ether, the composite nanoparticles may be mixed with the alkylene glycol monoalkyl ether in the form of a dispersion in the dialkylene glycol monoalkyl ether.

[0138] When the solvent is a combination of an alkylene glycol monoalkyl ether and a dialkylene glycol monoalkyl ether, the proportion of the dialkylene glycol monoalkyl ether may be 100 parts by mass or less relative to 100 parts by mass of the alkylene glycol monoalkyl ether, and is, for example, 0.01 to 50 parts by mass, preferably 0.1 to 30 parts by mass, further preferably 0.5 to 20 parts by mass, even more preferably 1 to 15 parts by mass, and most preferably 2 to 10 parts by mass.

[0139] The total proportion of the solvent is, for example, 50 to 5,000 parts by mass, preferably 100 to 4,000 parts by mass, further preferably 300 to 3,000 parts by mass, even more preferably 500 to 2,000 parts by mass, and most preferably 1,000 to 1,500 parts by mass, relative to 100 parts by mass of the silver-containing metal in the composite nanoparticles. If the proportion of the solvent is too low, film-forming properties may be reduced, and if it is too high, productivity and film-forming properties may be reduced.

[0140] The proportion of silver-containing metal nanoparticles in the liquid composition can be selected from a range of about 0.5 to 90 mass %, for example, 1 to 50 mass %, preferably 2 to 30 mass %, even more preferably 3 to 20 mass %, even more preferably 4 to 15 mass %, and most preferably 5 to 10 mass %.

[0141] The application method is not particularly limited, and a conventional coating method such as a flow coating method, a dispenser coating method, a spin coating method, a spray coating method, a screen printing method, a flexographic printing method, a casting method, a bar coating method, a curtain coating method, a roll coating method, a gravure coating method, a dipping method, a slit method, a photolithography method, an inkjet method, or an offset printing method can be used.

[0142] (Heating process) In the present invention, in the heating step (baking step), the nanometer-sized silver-containing metal nanoparticles contained in the composite nanoparticles are sintered and fixed together, thereby improving discoloration resistance.

[0143] In the heating step, the heating temperature (drying temperature or baking temperature) can be selected appropriately depending on the type and particle size of the composite nanoparticles, but is preferably 130°C or higher (particularly 150°C or higher), more preferably 160°C or higher. Since a higher heating temperature improves the discoloration resistance of the glossy silver film, a temperature of 170°C or higher is also acceptable. The heating temperature may be 130 to 300°C, preferably 150 to 250°C, and more preferably 170 to 200°C, because this increases the productivity of the glossy silver film and allows the use of objects to be decorated with low heat resistance. If the heating temperature is too low, the sintering of the silver-containing metal nanoparticles will not proceed sufficiently, resulting in insufficient adhesion between the particles and potentially reducing the discoloration resistance of the glossy silver film.

[0144] The heating time is, for example, 10 to 240 minutes, preferably 30 to 120 minutes, and more preferably 40 to 90 minutes.

[0145] (Manufacturing process of undercoat layer) When the decorative body of the present invention includes an undercoat layer, the undercoat layer is obtained through a pretreatment process for applying a silver gloss film onto the body to be decorated, which includes a coating process in which a liquid composition for forming an undercoat layer, for example, a liquid composition containing a (meth)acrylic resin having a hydroxyl group, a curing agent, and a solvent (second solvent), is applied onto the body to be decorated, and a curing process in which the coating film formed from the liquid composition is heated and cured to obtain the undercoat layer.

[0146] In the coating step of the undercoat layer, the liquid composition can be prepared by, for example, mixing a hydroxyl group-containing (meth)acrylic resin, a curing agent, and a solvent (second solvent) by a conventional method. A conventional stirring device can be used as the mixing method, and for example, a stirring and degassing device can be used.

[0147] The solvent preferably contains a polar organic solvent. Examples of the polar organic solvent include the polar organic solvents exemplified in the coating step of the silver layer. Among the polar organic solvents, it is preferable to contain one or more selected from alcohols, esters, alkylene glycol monoalkyl ethers, and dialkylene glycol monoalkyl ethers.2-6 Alkylene glycol mono C 1-3 Alkyl ethers are more preferred, C 4-6 Alkylene glycol mono C 1-2 Alkyl ethers are most preferred.

[0148] The proportion of the solvent is, for example, 10 to 1000 parts by mass, preferably 30 to 500 parts by mass, further preferably 50 to 300 parts by mass, even more preferably 80 to 200 parts by mass, and most preferably 100 to 150 parts by mass, relative to 100 parts by mass of the total of the (meth)acrylic resin having a hydroxyl group and the curing agent.

[0149] The coating method is not particularly limited, and any of the conventional coating methods exemplified in the coating step of the silver gloss film can be used.

[0150] The heating temperature of the coating film may be 60° C. or higher, for example, 60 to 300° C., preferably 100 to 280° C., more preferably 150 to 250° C., and even more preferably 170 to 200° C. The heating time is, for example, 5 to 120 minutes, preferably 10 to 60 minutes, and more preferably 20 to 40 minutes. [Example]

[0151] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0152] [Materials used] Polymer dispersant with carboxyl groups: "Disperbyk 190" manufactured by BYK-Chemie, solution of high molecular weight block copolymer with carboxyl groups, solvent: water, non-volatile components 40%, acid value 10 mg KOH / g, amine value 0 Acrylic resin A: DIC Corporation's "WXU-880", isocyanate-curing acrylic resin, non-volatile content 50%, hydroxyl value 10 mg KOH / g, glass transition temperature 90°C Acrylic resin B: "ARUFON UH2170" manufactured by Toagosei Co., Ltd., styrene acrylic resin, non-volatile content 98% or more, hydroxyl value 88 mg KOH / g, glass transition temperature 60°C Epoxy resin: Mitsubishi Chemical Corporation "jER828", bisphenol A type epoxy resin, epoxy equivalent weight 184-194 Silicone resin: Shin-Etsu Chemical Co., Ltd. "KR211", a methylphenyl silicone resin Isocyanate curing agent: "Takenate D-170N" manufactured by Mitsui Chemicals, Inc. Acid anhydride curing agent: "HN-2200" manufactured by Resonac Co., Ltd., 3 or 4-methyl-1,2,3,6-tetrahydrophthalic anhydride Curing accelerator: Mitsubishi Chemical Corporation's "jER Cure IBMI12", 1-isobutyl-2-methylimidazole Dimethylaminoethanol: Fujifilm Wako Pure Chemical Industries, Ltd. 1-Methoxy-2-propanol: Fujifilm Wako Pure Chemical Industries, Ltd., boiling point 120°C 3-Methoxy-3-methyl-1-butanol: "Solfit" manufactured by Kuraray Co., Ltd., boiling point 174°C Reactive diluent: Mitsubishi Chemical Corporation's "YED111AN", an alkyl monoglycidyl ether reactive diluent Substrate (glass plate): Matsunami Glass Industry Co., Ltd. "Water-resistant S9224", 1.5 mm thick

[0153] [Preparation of composite nanoparticle dispersion] (Composite nanoparticle A) 66.8 g of silver nitrate and 5.3 g of a polymer dispersant having a carboxyl group were added to 100 g of ion-exchanged water and stirred vigorously to obtain a suspension. 100 g of dimethylaminoethanol was gradually added to this suspension so that the water temperature did not exceed 50°C, and the mixture was heated and stirred in a water bath at 50°C for 4 hours to obtain a composite nanoparticle dispersion.

[0154] An excess amount of methanol was added to the obtained composite nanoparticle dispersion and stirred, followed by centrifugation to precipitate the composite nanoparticles, and the supernatant was removed. Methanol was added again and stirred, followed by centrifugation to precipitate the composite nanoparticles, and the supernatant was removed. Diethylene glycol monobutyl ether was added to the resulting methanol solution containing the precipitate, and the mixed methanol was removed using an evaporator to obtain a composite nanoparticle A dispersion with a silver content of 70 mass% in the dispersion. The particle size of the silver nanoparticles constituting composite nanoparticle A in this dispersion was confirmed using a transmission electron microscope (manufactured by JEOL Ltd.), and the number-average particle size of the primary particles (average of 200 particles) was 35 nm.

[0155] (Composite nanoparticle B) A composite nanoparticle B dispersion was prepared in the same manner as in the synthesis of composite nanoparticle A dispersion, except that the amount of polymer dispersant used was changed to 4.3 g. When the particle size of the silver nanoparticles constituting composite nanoparticle B was confirmed with a transmission electron microscope, the number-average particle size of the primary particles (average of 200 particles) was 45 nm.

[0156] (Composite nanoparticle C) A composite nanoparticle C dispersion was prepared in the same manner as in the synthesis of composite nanoparticle A dispersion, except that the amount of polymer dispersant used was changed to 8.5 g. When the particle size of the silver nanoparticles constituting composite nanoparticle C was confirmed with a transmission electron microscope, the number-average particle size of the primary particles (average of 200 particles) was 10 nm.

[0157] (Composite nanoparticle D) A dispersion of composite nanoparticles D was prepared in the same manner as in the synthesis of the dispersion of composite nanoparticles A, except that the amount of polymer dispersant used was changed to 6.9 g. When the particle size of the silver nanoparticles constituting composite nanoparticles D was confirmed with a transmission electron microscope, the number-average particle size of the primary particles (average of 200 particles) was 20 nm.

[0158] (Composite nanoparticle E) A dispersion of composite nanoparticles E was prepared in the same manner as in the synthesis of the dispersion of composite nanoparticles A, except that the amount of polymer dispersant used was changed to 2.7 g. When the particle diameter of the silver nanoparticles constituting composite nanoparticles E was confirmed with a transmission electron microscope, the number-average particle diameter of the primary particles (average of 200 particles) was 70 nm.

[0159] (Composite Nanoparticle F) 65.58 g of silver nitrate and 5.3 g of a polymer dispersant having a carboxyl group were added to 100 g of ion-exchanged water and stirred vigorously to obtain a suspension.

[0160] 1.40 g of copper (II) nitrate trihydrate and 2.93 g of a 1 mol / L aqueous nitric acid solution were taken and stirred in a water bath at 50°C to dissolve the copper (II) nitrate trihydrate, yielding an aqueous solution.

[0161] The suspension and the aqueous solution were mixed with stirring to obtain a mixed solution of a polymer dispersant having a carboxyl group, silver nitrate, and copper nitrate.

[0162] To this mixture, 100 g of dimethylaminoethanol was gradually added so that the water temperature did not exceed 50°C, and then the mixture was heated and stirred in a water bath at 50°C for 4 hours.

[0163] An excess amount of methanol was added to the resulting composite nanoparticle-containing dispersion and stirred. The silver / copper alloy nanoparticles were then precipitated by centrifugation, and the supernatant was removed. Methanol was added again and stirred. The composite nanoparticles were then precipitated by centrifugation, and the supernatant was removed. Diethylene glycol monobutyl ether was added to the resulting methanol solution containing the precipitate, and the mixed methanol was removed using an evaporator to obtain a composite nanoparticle F dispersion with a ratio of 99 parts by weight of silver to 1 part by weight and a silver / copper alloy content of 70% by weight. The particle size of the silver / copper alloy nanoparticles constituting composite nanoparticle F was confirmed using a transmission electron microscope (manufactured by JEOL Ltd.). The number-average particle size of the primary particles (average of 200 particles) was 35 nm.

[0164] (Composite nanoparticle G) A composite nanoparticle G dispersion was prepared in the same manner as in the synthesis of composite nanoparticle A dispersion, except that the amount of polymer dispersant used was changed to 12.7 g. When the particle size of the silver nanoparticles constituting composite nanoparticle G was confirmed with a transmission electron microscope, the number-average particle size of the primary particles (average of 200 particles) was 5 nm.

[0165] (Composite Nanoparticle H) A composite nanoparticle H dispersion was prepared in the same manner as in the synthesis of composite nanoparticle A dispersion, except that the amount of polymer dispersant used was changed to 1.6 g. When the particle size of the silver nanoparticles constituting composite nanoparticle H was confirmed with a transmission electron microscope, the number-average particle size of the primary particles (average of 200 particles) was 100 nm.

[0166] (Composite Nanoparticles I) A composite nanoparticle I dispersion was prepared in the same manner as in the synthesis of composite nanoparticle A dispersion, except that the amount of polymer dispersant used was changed to 1.1 g. When the particle size of the silver nanoparticles constituting composite nanoparticle I was confirmed with a transmission electron microscope, the number-average particle size of the primary particles (average of 200 particles) was 140 nm.

[0167] [Preparation of Metallic Ink Composition] The obtained dispersion of composite nanoparticles (A to I) was diluted by adding 1-methoxy-2-propanol in a mass ratio of 9 times, and then stirred and mixed using a stirring and degassing device ("Mazerustar" manufactured by Kurabo Industries, Ltd.) to prepare a metallic ink composition (silver content 7.0 mass%).

[0168] [Preparation of acrylic resin composition for undercoat layer] The components were stirred and mixed in the proportions shown in Table 1 using a stirring and degassing device to prepare an acrylic resin composition for the undercoat layer.

[0169] [Table 1]

[0170] [Preparation of Epoxy Resin Composition for Undercoat Layer] The components were stirred and mixed in the proportions shown in Table 2 using a stirring and degassing device to prepare an epoxy resin composition for the undercoat layer.

[0171] [Table 2]

[0172] [Preparation of evaluation samples] (Examples 1 to 10 and Comparative Examples 1 to 3, 6 to 8) Specifically, an evaluation sample was prepared by forming a silver gloss film on a substrate in the following manner.

[0173] (1) A substrate (glass plate) was placed in the acrylic resin composition for the undercoat layer and immersed (dipped) for several seconds. Then, the substrate was pulled up at a rate of 10 mm / second using a dip coater ("F225" manufactured by Asumi Giken Co., Ltd.) to obtain a substrate coated with the composition for the undercoat layer.

[0174] (2) For Undercoat Layer The substrate coated with the acrylic resin composition was dried by heating in an oven at 170°C for 60 minutes to form an undercoat layer on the substrate.

[0175] (3) Using the same method as in (1), a substrate coated with an undercoat layer was immersed (dipped) in a metallic ink composition containing composite nanoparticles (A to I) to obtain a substrate coated with the metallic ink composition.

[0176] (4) The substrate coated with the metallic ink composition was heated in an oven at the heating temperatures shown in Tables 8 and 9 for 60 minutes to sinter the silver nanoparticles.

[0177] (5) After heating, the evaluation samples were taken out to obtain evaluation samples in which a glossy silver film was formed on the substrate. The silver content in the glossy silver films obtained in Examples 1 to 10 was 92.6 to 97.6 mass %.

[0178] Comparative Example 4 A silver gloss film was produced in accordance with Example 2 of Patent Document 1. Specifically, a metallic ink composition was prepared by stirring and mixing 43.0 g of composite nanoparticles A, 5.3 g of acrylic resin B, 3.6 g of silicone resin, and 48.1 g of 3-methoxy-3-methyl-1-butanol using a stirring and degassing device. This metallic ink composition was applied to a glass plate using a 20 μm applicator, and then heated in an oven at 50°C for 10 minutes, followed by heating in an oven at 80°C for 60 minutes.

[0179] (Comparative Example 5) A glossy silver film was produced in the same manner as in Comparative Example 4, except that the heating temperature of the oven was changed from 80°C to 170°C.

[0180] Example 11 A silver glossy film was produced in the same manner as in Example 3, except that no undercoat layer was formed on the substrate.

[0181] Example 12 A silver glossy film was produced in the same manner as in Example 3, except that the epoxy resin composition for the undercoat layer was used instead of the acrylic resin composition for the undercoat layer.

[0182] [Measuring average film thickness] The cross section of the evaluation sample was observed with a scanning electron microscope (SEM), and the film thickness was measured at a total of 10 locations. The obtained values ​​were averaged to obtain the average film thickness.

[0183] [Evaluation and determination of various optical properties] For each evaluation sample of the examples and comparative examples, in order to determine whether a silver gloss film capable of solving the problem of the present application was obtained, the gloss (whether the reflectance is high and the specular surface is excellent), color (whether the color is bright silver-white), and discoloration resistance (whether the color difference before and after the weather resistance test is small and no discoloration occurs) were examined.

[0184] (1) Glossiness (reflectivity) The silver gloss film formed on the evaluation sample was subjected to a reflectance test (direct method) described in the "Reflectance Test" section of JIS D 5705:1993, and the gloss was judged according to the criteria shown in Table 3. The test equipment used was a mirror reflectometer ("MG-I 7000" manufactured by Nippon Denshoku Industries Co., Ltd.), and the incident angle was set to 25°. From the perspective of gloss (specular reflectivity of light), a silver gloss film rated "a" was deemed to pass.

[0185] [Table 3]

[0186] (2) Color (before weather resistance test) The brightness (L) of the silver gloss film formed on the evaluation sample was measured from the 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 (Shimadzu Corporation, "ISR-3100"). * ) and chromaticity (a * and b * ) was measured and evaluated according to the criteria shown in Table 4.

[0187] In addition, L * represents brightness (the larger the value, the brighter the light), and a * indicates the change in color tone from red to green (the more positive the value, the more reddish it is, and the more negative the value, the more greenish it is), and b * indicates a change in color tone from yellow to blue (the larger the positive value, the stronger the yellow tone, and the larger the negative value, the stronger the blue tone). In other words, the bright silvery white color that represents a vivid silver gloss film is * is large, and a * and b * It can be said that this is a color where the value is close to zero.

[0188] From the standpoint of color (whether it has a vivid silvery white color or not), a grade of B or higher was considered a pass.

[0189] [Table 4]

[0190] (3) Weather resistance test Using a xenon weather meter ("SC750-W" manufactured by Suga Test Instruments Co., Ltd.), irradiance: 120 W / m 2 The evaluation sample was treated under the conditions of a black panel temperature of 63°C and an irradiation time of 640 hours (corresponding to outdoor exposure for one year).

[0191] (4) Color (after weather resistance test) The brightness (L) of the silver gloss film formed on the evaluation sample after the weather resistance test was measured in the same manner as the evaluation sample before the weather resistance test. * ) and chromaticity (a * and b * ) was measured and evaluated according to the criteria shown in Table 4. From the viewpoint of color (whether or not a vivid silvery white color was exhibited), a rating of b or higher was considered to be acceptable.

[0192] (5) Discoloration resistance (color difference) Difference in brightness before and after weather resistance test (ΔL * ) and chromaticity difference (Δa * and Δb * ) and calculated the color difference (ΔE) based on the following formula, and evaluated according to the criteria shown in Table 5.

[0193] ΔE=[(ΔL * ) 2 +(Δa * ) 2 +(Δb * ) 2 ] 1 / 2

[0194] That is, ΔE is an index that indicates the change in color (discoloration) before and after a weather resistance test, and since it is desirable that discoloration due to use be small, particularly when used outdoors, it can be said that a small ΔE is desirable.

[0195] From the viewpoint of weather resistance (resistance to discoloration), a silver gloss film with a rating of b or higher was deemed to pass.

[0196] [Table 5]

[0197] (6) Adhesion The adhesion of the undercoat layer and the silver gloss film (decorative body) laminated on the substrate (glass plate) to the substrate was determined by a tape peeling test in accordance with the method specified in JIS K 5600-5-6 (cross-cut method). The tape used for the test was Cellotape (registered trademark) CT-18 manufactured by Nichiban Co., Ltd. The peeling state was classified according to the criteria of JIS K 5600-5-6 mentioned above, with classification 0 (the edges of the cut are completely smooth and there is no peeling at any of the grid squares) being considered "no peeling" and other classifications being considered "peeling," and the adhesion was evaluated according to the criteria shown in Table 6.

[0198] [Table 6]

[0199] (7) Overall Judgment Based on the evaluation of each evaluation item, an overall evaluation was made according to the criteria shown in Table 7.

[0200] [Table 7]

[0201] The evaluation results are shown in Tables 8 to 10.

[0202] [Table 8]

[0203] [Discussion of evaluation results] (Comparative Example 1) Comparative Example 1 is an example in which a metallic ink composition containing composite nanoparticles A with an average particle size of 35 nm was used, and the drying temperature was 80° C. In Comparative Example 1, the color was evaluated as a and presented a vivid silvery white color before the weather resistance test, but after the weather resistance test, it was evaluated as b * The color was evaluated as C (failure) and the color fastness was also evaluated as C (failure), so the overall evaluation was rank C.

[0204] SEM images (100,000x magnification) of the glossy silver film before and after the weather resistance test are shown in Figure 1 and Figure 2, respectively. Compared to Figure 1, which shows the film before the weather resistance test, Figure 2, which shows the film after the weather resistance test, shows that the silver nanoparticles have aggregated, causing a change in the arrangement of the silver particles.

[0205] That is, in the case of the glossy silver film of Comparative Example 1, the composite nanoparticles aggregated before and after the weather resistance test, causing a change in the arrangement of the silver particles, resulting in a change in color. As a result, the color difference ΔE was large and the color resistance was insufficient, and it was not possible to obtain the properties of a glossy silver film suitable for long-term use.

[0206] (Examples 1 and 2) Example 1 is an example in which the drying temperature was changed to 150°C from Comparative Example 1. In Example 1, before the weather resistance test, * Although the difference in thickness was slightly large and the color was rated b, the color remained at an acceptable level after the weather resistance test, and the color difference (ΔE) was also reduced, resulting in a b rating for the color fastness evaluation. Furthermore, by designing the thickness of the silver gloss film to be 200 nm or less, the specular reflectance of light was high and the gloss (specularity) was excellent (rated a), and the overall rating was rank B (pass). In the silver gloss film of Example 1, the sintering of the silver nanoparticles prevented the aggregation of the silver nanoparticles after the weather resistance test and prevented discoloration, and therefore a silver gloss film was obtained that was suitable for long-term use and achieved both gloss, color, and color fastness.

[0207] In Example 2, in which the composite nanoparticles A of Example 1 were changed to composite nanoparticles B with an average particle size of 45 nm, the silver nanoparticles were sintered, as in Example 1, which prevented the aggregation of the silver nanoparticles after the weather resistance test and prevented discoloration, and the gloss, color, and discoloration resistance were all evaluated as b or higher (pass), resulting in an overall ranking of B.

[0208] (Examples 3 to 6, Comparative Examples 2 to 3) Examples 3 and 4 are examples in which the drying temperature of Examples 1 and 2 was changed to 170°C. In Examples 3 and 4, the sintering of the silver nanoparticles was further strengthened, and the discoloration prevention effect was improved, so the discoloration resistance was further improved compared to Examples 1 and 2, and the results were rated as A. Furthermore, both before and after the weather resistance test, the L * is large, and a * and b * Since the bright silver-white color with a value close to zero was maintained, it was also excellent in terms of color (rating A), and since the evaluations of gloss, color, and resistance to discoloration all received an excellent rating of A, the overall rating was also Rank A. From the above results, in Examples 3 and 4, it was possible to obtain a silver gloss film that was most suitable for long-term use in all evaluation samples.

[0209] SEM images (100,000 magnification) of the glossy silver film obtained in Example 3 before and after the weather resistance test are shown in Figures 3 and 4, respectively, and SEM images (100,000 magnification) of the glossy silver film obtained in Example 4 before and after the weather resistance test are shown in Figures 5 and 6, respectively. In both images, the silver nanoparticles have sintered (solidified) and grown into large particles (the raw material particle morphology has disappeared), so no particle aggregation has occurred as in Comparative Example 1, and no change in the arrangement of the silver particles was observed even after the weather resistance test. In other words, the glossy silver films obtained in Examples 3 and 4 maintained the surface condition they had before the weather resistance test, even after the weather resistance test.

[0210] Example 5 is an example in which the drying temperature of Example 1 was changed to 130°C. *Although the color difference (ΔE) before and after the weather resistance test was slightly larger, the acceptable rank B for practical use was maintained.

[0211] Comparative Examples 2 and 3 are examples in which the drying temperature of Examples 1 and 2 was changed to 120° C. In Comparative Examples 2 and 3, the sintering of the silver nanoparticles was insufficient, and the discoloration prevention effect was insufficient. Perhaps because of this, the evaluation of color tone and the evaluation of discoloration resistance after the weather resistance test were both rated C (fail), and the overall evaluation was also ranked C.

[0212] From the results of Example 5 and Comparative Example 2, it can be said that a glossy silver film containing a sintered body of silver nanoparticles that is effective in preventing discoloration of the glossy silver film can be obtained by heating at 130° C. or higher (heating step).

[0213] Example 6 is an example in which the drying temperature of Example 1 was changed to 250°C. Compared to Example 3, in which the drying temperature was 170°C, there was no significant difference in each evaluation item, and the product was ranked A. Therefore, from the viewpoints of gloss, a color close to silvery white, and resistance to discoloration, it can be said that there is no upper limit to the heating temperature in the heating step.

[0214] (Comparative Examples 4 to 5) Comparative Example 4 is an example in which a glossy silver film was produced in accordance with Example 2 of Patent Document 1. Unlike the glossy silver films of Examples 1 to 6 and Comparative Examples 1 to 3, which are composed of a single layer, the glossy silver film of Comparative Example 4 has a laminated structure comprising an interfacial layer formed of composite nanoparticles A, an intermediate layer having a phase-separated structure (a structure in which the composite nanoparticles A and an acrylic resin B are separated into a first phase and a second phase containing the composite nanoparticles A and a silicone resin and having a lower silver content than the first phase), and a surface layer formed of composite nanoparticles A. Similar to Comparative Example 1, Comparative Example 4 also showed a large color difference (ΔE) before and after the weather resistance test, resulting in a rating of C (failure) in the evaluation of discoloration resistance, and therefore received an overall rating of C. In Comparative Example 4, the composite nanoparticles aggregated before and after the weather resistance test, causing a change in the arrangement of the silver particles, resulting in a change in color, and therefore insufficient discoloration resistance, making it impossible to obtain the glossy silver film properties suitable for long-term use.

[0215] Comparative Example 5 is an example in which the drying temperature of Comparative Example 4 was changed to 170°C. In Comparative Example 5, as in Comparative Example 4, the color difference (ΔE) before and after the weather resistance test was large, and the evaluation of discoloration resistance was rated c (fail), so the overall rating was ranked C. In Comparative Example 5, the thickness of the glossy silver film was large at 1000 nm, and even though the surface layer was sufficiently sintered, the composite nanoparticles in the intermediate layer aggregated before and after the weather resistance test, causing a change in the film structure and resulting in a change in color. This is probably because the color difference ΔE was large and discoloration resistance was insufficient, so it was not possible to obtain glossy silver film properties suitable for long-term use.

[0216] [Table 9]

[0217] (Examples 7 to 8, Comparative Example 6) In Examples 7-8 and Comparative Example 6, the composite nanoparticles in the metallic ink composition of Examples 3-4 were replaced with nanoparticles with smaller particle diameters: composite nanoparticles C with an average particle diameter of 10 nm, composite nanoparticles D with an average particle diameter of 20 nm, and composite nanoparticles G with an average particle diameter of 5 nm. In these examples, composite nanoparticles with smaller average particle diameters were used, and a tendency for discoloration resistance to decrease as the thickness of the glossy silver film decreased was observed. Specifically, in Example 3, where the glossy silver film had a thickness of 90 nm (average nanoparticle diameter of 35 nm), the color difference (ΔE) was 1.0; in Example 8, where the film thickness was 60 nm (average nanoparticle diameter of 20 nm), the color difference (ΔE) was 1.9; and in Example 7, where the film thickness was 30 nm (average nanoparticle diameter of 10 nm), the color difference (ΔE) was 4.7. As the film thickness decreased, the color difference (ΔE) before and after the weathering test increased, and discoloration resistance decreased, but the practical pass level (e.g., grade b or higher) was maintained. In Comparative Example 6, where the film thickness was further reduced to 20 nm (the average particle diameter of the nanoparticles was 5 nm), the color difference (ΔE) before and after the weather resistance test was large at 15.3 (rating c), and the film was rejected (rank C) from the standpoint of color fastness.

[0218] This result can be explained as follows. Reducing the thickness of a glossy silver film requires the use of physically small nanoparticles. However, reducing the particle size of the nanoparticles requires the addition of a large amount of organic protective colloid to suppress crystal growth due to particle collisions. However, adding a large amount of organic protective colloid results in a large amount of organic matter being contained in the glossy silver film, inhibiting sintering. Comparative Example 6, with a film thickness of 20 nm, contained too much organic protective colloid (polymer dispersant), resulting in a low proportion of silver components in the glossy silver film. This prevented the silver nanoparticles from sintering, and thus prevented the tarnish prevention effect in the weather resistance test. This likely resulted in a decrease in tarnish resistance. Therefore, the critical thickness of a glossy silver film that can achieve high sinterability and high tarnish resistance is between 30 nm and 20 nm. Furthermore, to enhance the tarnish resistance of a glossy silver film, it is preferable that the proportion of silver components in the glossy silver film be 90% by mass or more and that the average particle size of the silver nanoparticles used be 10 nm or more.

[0219] (Example 9, Comparative Examples 7 and 8) In Example 9 and Comparative Examples 7 and 8, the composite nanoparticles in the metallic ink composition of Examples 3 and 4 were changed to nanoparticles with a larger particle size. Composite nanoparticles E with an average particle size of 70 nm, composite nanoparticles H with an average particle size of 100 nm, and composite nanoparticles I with an average particle size of 140 nm were used, respectively. In these examples, composite nanoparticles with a larger average particle size were used, and a tendency for gloss to decrease as the thickness of the glossy silver film increased was observed. In detail, in Example 4, where the thickness of the glossy silver film was 120 nm (average particle size of nanoparticles: 45 nm), the reflectance was 86%, while in Example 9, where the thickness of the glossy silver film was 180 nm (average particle size of nanoparticles: 70 nm), the reflectance was 78%, and although gloss decreased, it maintained a practically acceptable level (rating b). In Comparative Example 7, where the film thickness was further increased to 250 nm (the average particle diameter of the nanoparticles was 100 nm), and Comparative Example 8, where the film thickness was 300 nm (the average particle diameter of the nanoparticles was 140 nm), the increase in film thickness caused a loss of surface smoothness, and light was diffusely reflected off the surface of the glossy silver film, reducing gloss (regular reflectivity of light). This resulted in a reflectivity of less than 75%, resulting in a C rating (failure), and the overall rating was also ranked C. Therefore, it can be said that the critical thickness of a glossy silver film that can achieve high gloss lies between 180 nm and 250 nm. Furthermore, in these cases, it can be said that the average particle diameter of the silver nanoparticles used in the glossy silver film is preferably 70 nm or less.

[0220] From the above results, it can be said that the film thickness (average thickness) of the silver gloss film is preferably in the range of 30 to 180 nm from the viewpoint of the balance between gloss (regular reflectivity of light), color tone close to silvery white, and resistance to discoloration.

[0221] Example 10 Example 10 is an example in which the metal component of the composite nanoparticles of Example 3 was changed from simple silver to a silver / copper alloy, with the silver / copper ratio by mass being 99 / 1. Example 10 did not differ significantly from Example 3 in each evaluation.

[0222] [Table 10]

[0223] (Examples 11 to 12) Example 11 is an example in which an undercoat layer was not provided, as opposed to Example 3, and Example 12 is an example in which the undercoat layer was changed to a curable epoxy resin composition, as opposed to Example 3. In these examples, there was almost no difference in gloss, color, or discoloration resistance compared to Example 3. Therefore, it is believed that the configuration of the undercoat layer does not affect gloss, color, or discoloration resistance.

[0224] (Effects obtained) From the above-mentioned verification results, in Examples 1 to 12, the problem of the present application was solved by designing the silver gloss film to contain a sintered body of silver-containing metal nanoparticles and to have a thickness of 30 to 180 nm, and the gloss (regular reflectivity of light) was high and the color tone (L) close to silver white was obtained without providing a topcoat layer. * is large, and a * and b * It was found that a glossy silver film with excellent resistance to discoloration (small color difference ΔE) before and after weather resistance testing could be obtained while maintaining a high colorfastness (color difference ΔE is close to zero). [Industrial Applicability]

[0225] The glossy silver film of the present invention can be used to improve the decorativeness of various objects (molded objects) to be decorated, and can be used for decorating and painting, for example, interior and exterior parts of automobiles, emblems, mobile phones, laptop computers, golf club shafts, cosmetic containers, etc.

Claims

1. A silver glossy film comprising a sintered body of silver-containing metal nanoparticles and having an average thickness of 25 to 200 nm.

2. Irradiance 120W / m ２ 2. The silver gloss film according to claim 1, which has a color difference ΔE of 5 or less before and after a weather resistance test conducted at a black panel temperature of 63° C. for 640 hours.

3. Lightness L ＊ is 90 or more, and chromaticity a ＊ and chromaticity b ＊ 3. The silver gloss film according to claim 1, wherein each of the values ​​is −6 to 6.

4. 3. The glossy silver film according to claim 1, wherein the proportion of the silver-containing metal nanoparticles in the glossy silver film is 90% by mass or more.

5. 3. The silver gloss film according to claim 1, wherein the silver-containing metal nanoparticles are silver nanoparticles.

6. 3. The silver gloss film according to claim 1, wherein the ratio of the resin component is 20 parts by mass or less per 100 parts by mass of the silver-containing metal nanoparticles.

7. A decorative body comprising an object to be decorated and the silver gloss film according to claim 1 or 2 laminated on the object to be decorated.

8. 8. The decorative body according to claim 7, wherein an undercoat layer is interposed between the object to be decorated and the silver gloss film.

9. 9. The decorative article according to claim 8, wherein the undercoat layer is formed from a cured product of a curable composition containing at least one resin selected from the group consisting of (meth)acrylic resins and epoxy resins.

10. 8. The decorative article according to claim 7, wherein the silver gloss film is the outermost surface layer.

11. A method for producing a decorative body according to claim 7, comprising a coating step of applying a liquid composition containing composite nanoparticles of silver-containing metal nanoparticles and a protective colloid onto an object to be decorated to form a coating film, and a heating step of heating the coating film at a temperature of 130°C or higher to obtain a silver gloss film.

12. The method according to claim 11, wherein the number average particle diameter of the silver-containing metal nanoparticles is 8 to 80 nm.

13. A method for imparting a silver luster to an object to be decorated, comprising laminating the silver luster film according to claim 1 or 2 on the object to be decorated.

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