JP2017190509A - Silver-plated coated body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silver-plated coated body having excellent durability by improving adhesiveness between an undercoat layer and a silver-plated layer.SOLUTION: A silver-plated coated body has in this order, on a substrate (resin, metal, glass), an undercoat layer containing an isocyanate compound and a compound having a thioether bond and a hydroxy group in the same molecule, an electroless silver-plated layer, and coating.SELECTED DRAWING: None

Description

  The present invention relates to a silver-plated coated body having at least an undercoat layer, a silver-plated layer, and a topcoat layer on a substrate. Specifically, the present invention relates to a silver-plated coated body that improves the adhesion between the undercoat layer and the silver-plated layer and has excellent durability.

  The silver-plated coated body having a silver-plated layer on the base material is processed into a metal or plastic surface because silver has the highest reflective gloss among metals, and is used as a design material or a reflective material. . Further, it is a material that can be effectively used as an electromagnetic shielding material, for example, utilizing the high conductivity of silver.

  The silver plating layer is a useful material exhibiting high reflection gloss and high conductivity even if it is a thin film, but its mechanical strength is weak because it is thin and soft. In order to make up for such drawbacks, it is known to provide a top coat layer on the surface using various hard coat materials. For example, JP 2000-129448 A describes that liquid epoxy resins, unsaturated polyester resins, fluororesins, acrylic resins, melamine resins, silicon resins, and the like can be used for the topcoat layer. JP, 2004-203014, A, etc. describe using a silicon acrylic paint having a specific glass transition temperature. Japanese Patent Application Laid-Open Nos. 2008-110101 and 2008-176050 describe that ultraviolet curable resins and electron beam curable resins may be used.

  However, even if these topcoat layers are provided, the adhesive strength between the substrate or the undercoat layer and the silver plating layer is weakened by exposing the silver-plated coating body to a high-temperature and high-humidity environment or an atmosphere containing salt water. There was a problem of becoming.

  On the other hand, in producing a silver-plated coated body, it is an effective means to improve the roughness of the substrate surface by providing an undercoat layer in order to utilize the good reflectance of the silver thin film layer. In addition, the undercoat layer of the silver-plated coated body is required to have excellent adhesion to the base material and excellent adhesion to the silver plating layer provided on the undercoat layer.

  As such an undercoat layer, for example, Japanese Patent Laid-Open No. 2001-164380 (Patent Document 1) describes an undercoat layer in which a mixed paint mainly composed of an alkyd resin and an unsaturated polyester resin is applied and dried. JP-A-2001-040486 (Patent Document 2) describes an undercoat agent containing an acrylic resin, an amino resin, an epoxy resin, and an alkoxytitanium ester in specific ratios. The publication (Patent Document 3) describes an undercoat layer containing a titanium alkoxide and a resin having a functional group hydrogen-bonded to a hydroxyl group bonded to titanium generated by hydrolysis of the titanium alkoxide.

  JP-A 2007-169585 (Patent Document 4) discloses a polyester resin, a polyester urethane resin, an alkyd resin, a styrenated alkyd (urethane) resin, an acrylic resin, an acrylated alkyd (as a resin contained in the undercoat layer). Urethane) resin, acrylic silicon resin, melamine resin, two-component curable polyurethane resin, epoxy resin, and the like are described. JP 2008-063592 A (Patent Document 5) describes acrylic resin, silicon acrylic resin, urethane resin, epoxy resin, and the like. It is described that resins, acrylate oligomers, acrylate monomers and the like can be used. In addition, JP-A-2009-249671, JP-A-2012-206326, JP-A-2014-108710 (Patent Document 6), etc. can use many various resins and resin additives for the undercoat layer. Is described.

  However, the above-mentioned conventional technology cannot solve the problem that the adhesion between the undercoat layer and the silver plating layer is lowered due to the long-term high temperature and high humidity environment or the influence of salt water, and further improvement is required. It was.

  On the other hand, Japanese Patent Application Laid-Open No. 2009-209246 (Patent Document 7) describes a compound having a sulfide bond and a hydroxyl group as a compound that can improve the adhesion property to the copper surface. ) Describes compounds having a sulfide bond, a mercapto group, etc. in the molecule as compounds capable of improving the conductivity of the transparent conductive layer obtained by the silver mirror reaction.

JP 2001-164380 A JP 2001-040486 A JP 2004-035996 A JP 2007-169685 A JP 2008-063592 A JP 2014-108710 A JP 2009-209246 A JP 2014-182966 A

  This invention makes it a subject to improve the adhesiveness of an undercoat layer and a silver plating layer, and to provide the silver plating coating body which has the outstanding durability.

The above object of the present invention is achieved by the invention described below.
A silver-plated coated body having at least an undercoat layer and a silver plating layer in this order on a substrate, wherein the undercoat layer contains an isocyanate compound and a compound having a thioether bond and a hydroxyl group in the same molecule. Silver-plated body.

  By this invention, it becomes possible to improve the adhesiveness of an undercoat layer and a silver plating layer, and to provide the silver plating coating body which has the outstanding durability.

  The present invention will be described in detail below.

  The silver-plated coated body of the present invention is a silver-plated coated body having at least an undercoat layer and a silver plated layer in this order on a substrate, and the undercoat layer has an isocyanate compound and a thioether bond and a hydroxyl group in the same molecule. Contains compounds.

  As the isocyanate compound contained in the undercoat layer of the present invention, biuret type, isocyanurate type, adduct type, and bifunctional type isocyanate compounds can be used. These isocyanate compounds are, for example, Duranate series commercially available from Asahi Kasei Corporation, Burnock series commercially available from DIC Corporation, Coronate series commercially available from Tosoh Corporation, or Mitsubishi Chemical Corporation. A commercially available Mytec series can be obtained and used. These isocyanate compounds may be used alone or as a mixture of a plurality of compounds.

  The undercoat layer of the present invention contains a polyol resin, and preferably contains an isocyanate compound as its curing agent. Examples of the polyol resin contained in the undercoat layer include polymers or oligomers having terminal hydroxyl groups such as alkyd polyol, polyester polyol, acrylic polyol, polyether polyol, polycarbonate polyol, and polycaprolactone polyol.

  The content of the isocyanate compound contained in the undercoat layer of the present invention depends on the amount of the functional group that reacts with the isocyanate contained in the paint of the undercoat layer, but is generally 1 to 50 mass relative to the solid content of the undercoat. %, And more preferably 5 to 30% by mass. If the amount of the isocyanate compound is too large, defects may occur in the undercoat layer due to unnecessary chemical reaction such as generation of carbon dioxide gas by reaction of unreacted isocyanate groups with water. If the amount is too small, the strength of the undercoat layer cannot be maintained sufficiently.

  The polyol resin as described above can be easily obtained as a commercially available two-component urethane paint. For example, Mirror Shine Undercoat Clear D-1 commercially available from Ohashi Chemical Industry Co., Ltd. or Under Black No. 128.

  The undercoat layer of the present invention further contains a compound having a thioether bond and a hydroxyl group in the same molecule (hereinafter referred to as a thioether compound). Two or more thioether bonds may be present in the same molecule, and preferably one or more thioether bonds per 150 molecular weight. A plurality of hydroxyl groups may be present in the same molecule, preferably 1 to 3, and more preferably 2. Specific examples of the thioether compound used in the present invention are shown below, but the present invention is not limited thereto.

  The content of the thioether compound used in the undercoat layer of the present invention is preferably about 0.1 to 30% by mass, more preferably 0.5 to 5% by mass with respect to the solid content of the undercoat. . When there is too much content of a thioether compound, the physical property of a coating film may fall, and when too small, the effect of this invention is not fully acquired.

  In addition to the polyol resin described above, the undercoat layer of the present invention is, for example, epoxy resin, polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, poly (N-vinylcarbazole), carbonized. Contains other resins such as hydrogen resin, ketone resin, phenoxy resin, polyamide, ethyl cellulose, vinyl acetate, ABS resin, melamine resin, urea resin, benzoguanamine resin, unsaturated polyester resin, alkyd resin, silicon resin alkoxytitanium ester be able to. In that case, the content of the resin other than the polyol resin is preferably 30% by mass or less of the content of the polyol resin, and the undercoat layer can contain a curing agent suitable for the various resins described above.

  A curing accelerator may be used in the undercoat layer of the present invention. Curing accelerators include urethane curing accelerator from Nagashima Co., Ltd., drying accelerator A from Sansei Paint Industry Co., Ltd., Nitto Bussan Co., Ltd., San Apro Co., Ltd., Nippon Chemical Industry Co., Ltd., and Mitsubishi Chemical Corporation. 1,8-diazabicyclo [5,4,0] undecene-7 and 1,5-diazabicyclo [4,3,0] nonene-5 phenol salts, oleates and octylates commercially available as accelerators Etc. can be used. It is preferable that the usage-amount of a hardening accelerator is 1 mass% or less with respect to the solid content of an undercoat.

  The undercoat layer of the present invention may contain a leveling agent in order to improve the surface quality. As a leveling agent, a silicon leveling agent, a fluorine leveling agent, etc. can be obtained and used from Tohshin Chemical Co., Ltd., DIC Corporation, BYK Corporation or the like. The amount of the leveling agent used is preferably 0.001 to 1% by mass, more preferably 0.005 to 0.5% by mass, based on the solid content of the undercoat. If these leveling agents are added in an excessive amount, the adhesion to the silver plating layer tends to be weakened. If the amount is too small, the leveling effect cannot be sufficiently obtained.

  In the present invention, as a method for providing an undercoat layer on a substrate, it is common to dissolve the above-described resin composition or the like in an organic solvent and apply the solution on the substrate. The coating method may be a conventionally known coating method, for example, gravure roll method, reverse roll method, dip roll method, bar coater method, die coater method, curtain coater method, knife coater method, air spray method, airless spray method. And a coating method such as a dip method. Among these, an air spray method that can be applied to a complicated surface shape is a particularly preferable method. The thickness of the undercoat layer is preferably 5 to 30 μm, but is not particularly limited.

  Examples of the organic solvent used for forming the undercoat layer include hydrocarbons such as cyclohexane and Solvesso 100 (trade name, manufactured by Exxon Chemical), cellosolve, methyl cellosolve, butyl cellosolve, carbitol, diethylcarbitol and the like. Ethers, methanol, ethanol, isopropyl alcohol, butyl alcohol, cyclohexanol and other alcohols, ethyl acetate, n-butyl acetate, isobutyl acetate, amyl formate, isoamyl acetate, isobutyl acetate, butyl propionate, isopropyl butyrate, butyric acid Ethyl, butyl butyrate, alkyl esters, methyl lactate, ethyl lactate, methyl oxyacetate, ethyl oxyacetate, butyl oxyacetate, methyl methoxyacetate, ethyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate Esters such as ethyl ethoxy acetate, diethylene glycol dimethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether , Ethers such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, and ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 2-heptanone, and 3-heptanone. The present invention is not limited to Rugakore. These organic solvents are appropriately selected from the viewpoint of the surface quality and the solubility of the resin composition used for providing the undercoat layer, and can be used alone, but are often used in combination of two or more. .

  The silver-plated coating body of this invention has a silver plating layer on the undercoat layer provided on the base material. The preferred method for forming the silver plating layer is to treat the surface of the undercoat layer on which the silver plating layer is to be formed with a silver mirror-containing active treatment solution containing stannous chloride to carry stannous ions on the surface of the undercoat layer. And a silver plating layer is formed on the activated undercoat layer by a silver mirror reaction.

  The treatment method for treating with an active treatment solution for silver mirror containing stannous chloride includes a method of immersing the surface of the undercoat layer for forming the silver plating layer in the active treatment solution for silver mirror, and an undercoat for forming the silver plating layer. There is a method of applying an active treatment solution for silver mirror containing stannous chloride or the like on the surface of the coating layer. As the coating method, spray coating that does not select the shape of the substrate is particularly suitable. Furthermore, it is preferable to wash the activation treatment liquid adhering to the surface with deionized water or purified distilled water.

  Examples of the active treatment liquid for silver mirror containing stannous chloride include activation treatment liquids described in JP 2007-197743 A, JP 2006-274400 A, and the like.

  You may provide the process of performing the activation process by silver ion after the process processed with the active process liquid for silver mirrors. An example of the activation treatment with silver ions is a treatment with a treatment solution containing silver nitrate. The concentration of the silver nitrate aqueous solution used in this step is preferably a dilute solution of 0.1 mol / L or less, and this solution is brought into contact with the undercoat layer treated with stannous chloride. When performing this silver ion treatment, it is preferable to wash with deionized water after the silver ion treatment. For these activation processes, spray coating in which a new solution is always supplied is suitable.

  Formation of the silver plating layer by silver mirror reaction is performed on the surface of the undercoat layer that has been subjected to the above activation treatment by using two solutions of an ammoniacal silver nitrate solution containing silver nitrate and ammonia and a reducing agent solution containing a reducing agent and a strong alkali component. Apply to mix. As a result, an oxidation-reduction reaction occurs, so that metallic silver is deposited and a silver coating is formed to form a silver plating layer.

  Examples of the reducing agent solution include an aqueous solution of an aldehyde compound such as glucose and glyoxal, an aqueous solution of a hydrazine compound such as hydrazine sulfate, hydrazine carbonate or hydrazine hydrate, and an aqueous solution such as sodium sulfite or sodium thiosulfate.

  Several additives may be added to the aqueous ammoniacal silver nitrate solution to produce good silver. For example, monoethanolamine, tris (hydroxymethyl) aminomethane, 2-amino-2-hydroxymethyl-1,3-propanediol, 1-amino-2-propanol, 2-amino-1-propanol, diethanolamine, diisopropanol Examples include amino alcohol compounds such as amine, triethanolamine and triisopropanolamine, amino acids such as glycine, alanine and sodium glycine, and salts thereof, but are not particularly limited.

  As a method of applying the two solutions of the ammoniacal silver nitrate solution and the reducing agent solution so as to be mixed on the surface on which the silver plating layer is to be formed, two kinds of aqueous solutions are mixed in advance, and this mixed solution is mixed with a spray gun or the like. A method of spraying on the surface of the undercoat layer, a method of spraying using a concentric spray gun having a structure in which two types of aqueous solutions are mixed and immediately discharged in the head of the spray gun, and two types of aqueous solutions using two spray nozzles There are a method in which each of the two-head spray guns is discharged and sprayed, and a method in which two types of aqueous solutions are sprayed simultaneously using two separate spray guns. These can be arbitrarily selected according to the situation.

  Subsequently, it is preferable to wash the surface of the silver plating layer with deionized water or purified distilled water to remove the solution after the silver mirror reaction remaining on the surface. Moreover, before providing the above-mentioned topcoat layer on the silver plating layer, for the purpose of stabilizing the deposited metallic silver, it is immersed in a solution containing an organic compound having a reaction or affinity with silver, or applying the solution. Surface treatment can be performed.

  As the organic compound, a nitrogen-containing heterocyclic compound having a thiol group or a thione group is effectively used. Examples of the heterocyclic ring of the nitrogen-containing heterocyclic compound include imidazole ring, imidazoline ring, thiazole ring, thiazoline ring, oxazole ring, oxazoline ring, pyrazoline ring, triazole ring, thiadiazole ring, oxadiazole ring, tetrazole ring, pyridine ring. , A pyrimidine ring, a pyridazine ring, a pyrazine ring, a triazine ring, a quinoline ring, and the like. Among them, an imidazole ring, a triazole ring, and a tetrazole ring are preferable. Specific examples include 2-mercapto-4-phenylimidazole, 2-mercapto-1-benzylimidazole, 2-mercapto-benzimidazole, 1-ethyl-2-mercapto-benzimidazole, 2-mercapto-1-butyl-benzimidazole. 1,3-diethyl-benzimidazoline-2-thione, 1,3-dibenzyl-imidazolidine-2-thione, 2,2'-dimercapto-1,1'-decamethylene-diimidazoline, 2-mercapto-4- Phenylthiazole, 2-mercapto-benzothiazole, 2-mercaptonaphthothiazole, 3-ethyl-benzothiazoline-2-thione, 3-dodecyl-benzothiazoline-2-thione, 2-mercapto-4,5-diphenyloxazole, 2 -Mercaptobenzoxazole, -Pentyl-benzoxazoline-2-thione, 1-phenyl-3-methylpyrazolin-5-thione, 3-mercapto-4-allyl-5-pentadecyl-1,2,4-triazole, 3-mercapto-5-nonyl 1,2,4-triazole, 3-mercapto-4-acetamido-5-heptyl-1,2,4-triazole, 3-mercapto-4-amino-5-heptadecyl-1,2,4-triazole, 2- Mercapto-5-phenyl-1,3,4-thiadiazole, 2-mercapto-5-n-heptyl-oxathiazole, 2-mercapto-5-n-heptyl-oxadiazole, 2-mercapto-5-phenyl-1 , 3,4-oxadiazole, 2-heptadecyl-5-phenyl-1,3,4-oxadiazole, 5-mercapto-1 Phenyl-tetrazole, 2-mercapto-5-nitropyridine, 1-methyl-quinoline-2 (1H) -thione, 3-mercapto-4-methyl-6-phenyl-pyridazine, 2-mercapto-5,6-diphenyl- Pyrazine, 2-mercapto-4,6-diphenyl-1,3,5-triazine, 2-amino-4-mercapto-6-benzyl-1,3,5-triazine, 1,5-dimercapto-3,7- And diphenyl-s-triazolino [1,2-a] -s-triazoline.

  Since the metallic silver formed as described above is easily damaged, it is preferable to further provide a topcoat layer on the surface of the silver plating layer. The top coat layer is preferably formed using a heat or photo-curable top coat resin composition from the viewpoint of scratch resistance.

  As the coating composition used for coating the topcoat layer of the silver-plated coating body of the present invention, a coating composition containing a thermosetting resin is common. Examples of the thermosetting resin include an epoxy resin, an unsaturated polyester resin, a melamine resin, a silicon resin, and the like described in JP 2000-129448 A, JP 2002-256454 A, and JP 2003-155580 A, for example. Examples thereof include urethane resin and acrylic silicon resin. Among these, since the application is easy, a coating composition containing a melamine resin, a urethane resin, and an acrylic silicon resin is preferably used.

  As the coating composition containing a urethane resin, a two-component curable urethane coating composition in which an isocyanate compound as a curing agent is mixed with a polymer or oligomer such as alkyd polyol, polyester polyol, and acrylic polyol is preferable. As the coating composition containing the acrylic silicone resin, an acrylic silicone coating in which an acrylic silane compound (silicone curing agent) is mixed as an acrylic resin and a curing agent is preferable.

  As commercially available thermosetting paints, for example, “Origid Tsuk # 100” (acrylic silicone paint) manufactured by Origin Electric Co., Ltd., “Hipolynal No. 800S” (acrylic silicone paint) manufactured by Ohashi Chemical Industry Co., Ltd. ), “Omak No. 100 (E) clear FV” (acrylic silicone paint), “Neohard clear H” (melamine paint), or the like is preferably used.

  As a method for providing a topcoat layer made of a thermosetting resin, it is common to apply the coating composition by dissolving or diluting it in an organic solvent. As such an organic solvent, the same organic solvent as that used when forming the undercoat layer can be used.

  These organic solvents are appropriately selected depending on the solubility of the coating composition and from the viewpoint of improving the quality of the coated surface, and are used alone, but are often used in combination of two or more. As a coating method of the coating composition used for coating the top coat layer, a conventionally known coating method may be used. For example, a gravure roll method, a reverse roll method, a dip roll method, a bar coater method, a knife coater method, Examples include an air spray method, an airless spray method, and a dip method. Among these, an air spray method that can be applied to a complicated surface shape is a particularly preferable method.

  In order to coat the topcoat layer, a coating composition containing an ultraviolet curable resin can also be used. As the ultraviolet curable resin preferably used, monomers and oligomer compounds mainly containing an ethylenically unsaturated group are preferably used, including an electron curable resin and curable with ultraviolet rays. Specific examples include amide monomers, (meth) acrylate monomers, urethane acrylates, polyester (meth) acrylates, and epoxy (meth) acrylates. Examples of amide monomers include amide compounds such as N-vinylpyrrolidone, N-vinylcaprolactam, and acryloylmorpholine. (Meth) acrylate monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxyalkyl (meth) acrylates such as 2-hydroxy-3-phenylpropyl acrylate, phenoxyethyl (meth) Acrylates of alkylene oxide adducts of phenols such as acrylates and their halogen nucleus substitutes, mono- or di (meth) acrylates of ethylene glycol, mono (meth) acrylates of methoxyethylene glycol, mono- or di (meth) of tetraethylene glycol Mono- or di (meth) acrylates of glycol, such as acrylate, mono- or di (meth) acrylate of tripropylene glycol; trimethylolpropane tri (meth) acrylate, (Meth) acrylic acid ester of polyols such as taerythritol tri (meth) acrylate and pentaerythritol tetra (meth) acrylate and dipentaerythritol hexaacrylate and alkylene oxides thereof, isocyanuric acid EO modified di- or tri (meth) acrylate, etc. Is mentioned.

  Examples of the urethane (meth) acrylate oligomer include a reaction product obtained by further reacting a hydroxyl group-containing (meth) acrylate with a polyol and an organic polyisocyanate reaction product. Here, examples of the polyol include a low molecular weight polyol, polyethylene glycol, and polyester polyol, and examples of the low molecular weight polyol include ethylene glycol, propylene glycol, cyclohexanedimethanol, and 3-methyl-1,5-pentanediol. Examples of the polyether polyol include polyethylene glycol and polypropylene glycol. Examples of the polyester polyol include these low molecular weight polyols and / or polyether polyols, adipic acid, succinic acid, phthalic acid, hexahydrophthalic acid and terephthalic acid. And a reaction product with an acid component such as a dibasic acid or an anhydride thereof. Examples of the organic polyisocyanate include tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. Examples of the hydroxyl group-containing (meth) acrylate include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate.

  As a polyester (meth) acrylate oligomer, the dehydration condensate of a polyester polyol and (meth) acrylic acid is mentioned. Examples of the polyester polyol include low molecular weight polyols such as ethylene glycol, polyethylene glycol, cyclohexanedimethanol, 3-methyl-1,5-pentanediol, propylene glycol, polypropylene glycol, 1,6-hexanediol and trimethylolpropane, and these And a reaction product from a polyol such as an alkylene oxide adduct and an acid component such as a dipic acid such as adipic acid, succinic acid, phthalic acid, hexahydrophthalic acid and terephthalic acid, or an anhydride thereof. Epoxy acrylate is obtained by addition reaction of unsaturated carboxylic acid such as (meth) acrylic acid to epoxy resin. Epoxy (meth) acrylate of bisphenol A type epoxy resin, epoxy (meth) of phenol or cresol novolac type epoxy resin Examples thereof include (meth) acrylic acid addition reactants of acrylate and polyether diglycidyl ether.

  Photopolymerization initiators include benzoin such as benzoin, benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether and alkyl ethers thereof; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenyl Acetophenones such as acetophenone, 1,1-dichloroacetophenone, 1-hydroxyacetophenone, 1-hydroxycyclohexyl phenyl ketone and 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one; 2 -Anthraquinones such as methyl anthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone and 2-amylanthraquinone; 2,4-dimethylthioxa Thioxanthone such as benzene, 2,4-diethylthioxanthone, 2-chlorothioxanthone and 2,4-diisopropylpyroxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; 2,4,6-trimethylbenzoyl diphenylphosphine oxide and the like Monoacylphosphine oxide or bisacylphosphine oxide; benzophenones such as benzophenone; and xanthones. These photopolymerization initiators can be used alone or in combination with a benzoic acid-based or amine-based photopolymerization initiation accelerator.

  The content of the photopolymerization initiator is preferably 0.01 to 20% by mass and particularly preferably 0.5 to 7% by mass with respect to the ultraviolet curable resin.

  In order to cure the coating composition used for coating the topcoat layer, heating may be applied in the case of a thermosetting resin, and electron beam, ultraviolet light, or the like may be irradiated in the case of an ultraviolet curable resin. . Examples of means for irradiating with electron beams and ultraviolet rays include lamp light sources such as xenon lamps, halogen lamps, tungsten lamps, high pressure mercury lamps, ultrahigh pressure mercury lamps, metal halide lamps, medium pressure mercury lamps, low pressure mercury lamps, argon ion lasers, YAG lasers, and excimers. Laser light sources such as laser and nitrogen laser are listed.

  The thickness of the top coat layer made of thermosetting resin is preferably in the range of 10 to 25 μm, and the top coat made of ultraviolet curable resin is preferably in the range of 3 to 10 μm. If the layer is too thin, the function of protecting the silver plating layer cannot be obtained, and a uniform coating film cannot be formed. On the other hand, if it is too thick, the peripheral portion is locally thickened further. Furthermore, since the light transmission distance becomes longer and the light loss increases, the reflectance of the silver plating layer is lowered, which is not preferable.

  Coloring materials such as pigments and dyes may be added to the top coat layer in order to improve design properties. Examples of pigments include organic pigments such as carbon black, quinacridone, naphthol red, cyanine blue, cyanine green, and hansa yellow; inorganics such as titanium oxide, aluminum oxide, calcium carbonate, barium sulfate, mica, petal, and composite metal oxides. Examples thereof include, but are not limited to, pigments. One or a combination of two or more selected from these pigments can be used. The dispersion of the pigment is not particularly limited, and a method of directly dispersing the pigment powder by a usual method, for example, dynomeal, paint shaker, sand mill, ball mill, kneader, roll, dissolver, homogenizer, ultrasonic vibration, stirrer, etc. Is used. At that time, it is possible to use a dispersant, a dispersion aid, a thickener, a coupling agent and the like. The amount of the pigment to be added is not particularly limited because the concealability varies depending on the type of pigment, but is usually 0.1 to 5% by mass with respect to the solid content of the cured resin component in the total amount of each composition.

  Examples of dyes include azo, anthraquinone, indoidoid, sulfide, triphenylmethane, xanthene, alizarin, acridine, quinoneimine, thiazole, methine, nitro, and nitroso dyes. Although it is mentioned, it is not limited to these. One or a combination of two or more selected from these dyes can be used. The addition amount of the dye is not particularly limited because the concealability varies depending on the type of the dye, but is usually 0.1 to 5% by mass with respect to the solid content of the cured resin component in the total amount of each composition.

  The top coat layer may further contain a leveling agent, metal powder, glass powder, antibacterial agent, antioxidant, ultraviolet absorber, light stabilizer and the like as additives. Further, in order to improve the adhesion between the top coat layer and the silver plating layer, it contains compounds such as thiols and silane coupling agents described in JP 2012-206326 A or JP 2014-65268 A. May be.

  Various plastics, metals, glasses, rubbers and the like are used as the base material of the silver-plated coated body of the present invention. Examples of the plastics include polycarbonate resin, acrylic resin, ABS resin, vinyl chloride resin, epoxy resin, phenol resin, polyethylene terephthalate (PET) resin, polyester resin such as polybutylene terephthalate (PBT) resin, fluorine resin, polypropylene ( PP) resin, a resin obtained by compounding these, and fiber reinforced plastic (FRP) reinforced with organic fibers such as nylon fiber and pulp fiber may be mentioned, but not particularly limited. Examples of the metal include, but are not limited to, iron, aluminum, stainless steel, copper, and brass. The glass is not particularly limited, such as inorganic glass or plastic glass.

  Although the silver-plated coating body of this invention has an undercoat layer on a base material, adhesion with an undercoat layer and a base material may not be enough depending on the kind of base material. In such a case, the base material may be pretreated for the purpose of improving the adhesion between the base material and the undercoat layer. Examples of the pretreatment method include wet methods such as detergent, solvent washing and ultrasonic washing, and dry treatment such as corona treatment, ultraviolet irradiation, and electron beam irradiation treatment. Depending on the type of base material, for example, a primer layer may be provided between the base material and the undercoat layer in order to improve adhesion in polypropylene and to prevent rust in iron and aluminum.

  EXAMPLES Hereinafter, although this invention is demonstrated using an Example, this invention is not limited by this description. In the following description, “%” and “part” are based on mass unless otherwise specified.

(Comparative Example 1)
Acrylic polyol resin (Ohashi Chemical Mirror Shine Undercoat Clear D-1) is mixed with isocyanate compound (Ohashi Chemical Industries Mirror Shine Undercoat Curing Agent N) and thinner (methyl ethyl ketone and butyl cellosolve in a ratio of 1: 1. ) At a mass ratio of 10: 2: 10. Furthermore, a leveling agent (BYK-323 manufactured by BYK Co., Ltd.) is added to this mixed solution so as to be 0.05% by mass with respect to the acrylic polyol resin solid content to obtain a urethane resin coating composition for an undercoat layer. It was. The above coating composition was applied to an ABS resin plate whose surface was washed with isopropanol and dried with a spray gun, and then heated and dried at 80 ° C. for 1 hour to form an undercoat layer having a thickness of 20 μm.

  The silver mirror activation treatment solution containing 0.1 mol of hydrochloric acid and 0.1 mol of stannous chloride is made up to 1000 g with water, sprayed onto the undercoat layer by a spray gun, and then deionized. Washed with water. Subsequently, 0.05 mol of silver nitrate was dissolved in water to 1000 g, and this liquid was sprayed with a spray gun to carry out activation treatment with silver ions, and then washed with deionized water.

  The silver mirror plating solution was prepared as follows. Separately, a silver nitrate solution in which 20 g of silver nitrate was dissolved in deionized water to 1000 g, and an ammonia solution in which 100 g of 28% aqueous ammonia solution and 5 g of monoethanolamine were dissolved in deionized water to 1000 g were prepared. Prior to use, the silver nitrate solution and the ammonia solution were mixed one-to-one to obtain an ammoniacal silver nitrate solution. Next, 10 g of hydrazine sulfate, 5 g of monoethanolamine and 10 g of sodium hydroxide were dissolved in deionized water to prepare 1000 g of a reducing agent solution.

  The ammoniacal silver nitrate solution and the reducing agent solution thus obtained were simultaneously sprayed using a double-head spray gun to form a silver plating layer, washed with deionized water, and sufficiently removed the surface water. And dried at 45 ° C. for 30 minutes.

  A top coat layer was provided on the silver plating layer. The main resin of acrylic silicon paint (Ohmak No. 100 (E) Clear FV, manufactured by Ohashi Chemical Industries), a hardener for silicon (Ohmak No. 100 hardener W, manufactured by Ohashi Chemical), thinner (methyl ethyl ketone and butyl cellosolve 1) : 1) was mixed at a mass ratio of 6: 1: 6 to obtain an acrylic silicon coating composition for the topcoat layer, which was spray-coated on the silver plating layer with a spray gun. A 15 μm top coat layer was formed by heating and drying at 80 ° C. for 30 minutes. In this way, a silver-plated coated body obtained by performing silver mirror plating on the ABS resin was obtained.

Example 1
The thioether compound A-1 was added to the coating composition for the undercoat layer of Comparative Example 1 at 0.5% based on the resin solid content contained in the coating composition for the undercoat layer. In the same manner as in Comparative Example 1, a silver-plated coated body was obtained.

(Example 2)
Comparative example except that the coating composition for the undercoat layer of Comparative Example 1 contained thioether compound A-1 at 1% based on the resin solid content contained in the coating composition for the undercoat layer. In the same manner as in No. 1, a silver-plated coated body was obtained.

(Example 3)
Comparative Example except that the coating composition for the undercoat layer of Comparative Example 1 contains the thioether compound A-1 at 3% based on the resin solid content contained in the coating composition for the undercoat layer. In the same manner as in No. 1, a silver-plated coated body was obtained.

Example 4
Comparative Example except that the coating composition for the undercoat layer of Comparative Example 1 contains thioether compound A-1 at 5% based on the resin solid content contained in the coating composition for the undercoat layer. In the same manner as in No. 1, a silver-plated coated body was obtained.

(Example 5)
Comparative Example, except that the coating composition for the undercoat layer of Comparative Example 1 contained thioether compound A-2 at 1% based on the resin solid content contained in the coating composition for the undercoat layer. In the same manner as in No. 1, a silver-plated coated body was obtained.

(Example 6)
Comparative Example except that the coating composition for the undercoat layer of Comparative Example 1 contains thioether compound A-3 at 1% based on the resin solid content contained in the coating composition for the undercoat layer. In the same manner as in No. 1, a silver-plated coated body was obtained.

(Example 7)
Comparative Example except that the coating composition for the undercoat layer of Comparative Example 1 contains thioether compound A-4 at 1% based on the resin solid content contained in the coating composition for the undercoat layer. In the same manner as in No. 1, a silver-plated coated body was obtained.

(Example 8)
Comparative example except that the coating composition for the undercoat layer of Comparative Example 1 contains thioether compound A-5 at 1% based on the resin solid content contained in the coating composition for the undercoat layer. In the same manner as in No. 1, a silver-plated coated body was obtained.

Example 9
Comparative Example except that the coating composition for the undercoat layer of Comparative Example 1 contains thioether compound A-14 at 1% based on the resin solid content contained in the coating composition for the undercoat layer. In the same manner as in No. 1, a silver-plated coated body was obtained.

(Comparative Example 2)
Comparison except that the coating composition for the undercoat layer of Comparative Example 1 contains the following thioether compound B-1 so as to be 1% with respect to the resin solid content contained in the coating composition for the undercoat layer. In the same manner as in Example 1, a silver-plated coated body was obtained.

(Comparative Example 3)
An epoxy resin (ADEKA Resin EP-4000 manufactured by ADEKA Corporation, epoxy equivalent 320) is mixed with a curing agent (metaphenylenediamine) and thinner (a mixture of methyl ethyl ketone and butyl cellosolve in a ratio of 1: 1) at a mass ratio of 10: 2: 10. The ratio was mixed. Furthermore, the thioether compound A-1 is 1% with respect to the resin solids so that the leveling agent (BYK-BYC-323 BYK-323) is 0.05% by mass with respect to the resin solids. Thus, an epoxy resin coating composition for an undercoat layer was obtained. This coating composition was applied to a substrate in the same manner as in Comparative Example 1 to form an undercoat layer. The substrate coated with the undercoat thus obtained was subjected to silver mirror plating in the same manner as in Comparative Example 1, and further coated with a top coat layer to obtain a silver-plated coated body.

<Evaluation method>
(Salt water resistance test)
The silver-plated coated bodies obtained in Examples and Comparative Examples were scratched on the cross with a cutter so as to reach the ABS base material from the topcoat layer surface. These samples were sprayed with a salt spray tester (model STP-90) from Suga Test Co., Ltd. for 10 days in an environment of 35 ° C. for 10 days. The sample sprayed with salt water was washed with water, dried, and the cellophane tape was strongly applied from above the part where the cross was scratched, and then the tape was peeled off.
○: The width of the widest part of the paint peeling is less than 2 mm from the center of the cut line. Δ: The widest part of the paint peeling is not less than 2 mm and less than 4 mm from the center of the cut line. The width of the part is 4mm or more from the center of the cut line

(Moisture resistance test)
Similar to the salt spray test, a sample in which a cross was scratched with a cutter was stored for 10 days in an environment of a temperature of 65 ° C. and a humidity of 95%. Thereafter, the sample was washed with water, dried, and the cellophane tape was strongly applied from above the part where the cross was scratched, and then the tape was peeled off.
○: The width of the widest part of the paint peeling is less than 1 mm from the center of the cut line. Δ: The widest part of the paint peeling is 1 mm or more and less than 2 mm from the center of the cut line. The width of the part is 2mm or more from the center of the cut line

  As is apparent from Table 1, the present invention provides a silver-plated coated body that improves the adhesion between the undercoat layer and the silver-plated layer and has excellent durability against high-temperature and high-humidity environments and salt water. Can do.

Claims (1)

  A silver-plated coated body having at least an undercoat layer and a silver plating layer in this order on a substrate, wherein the undercoat layer contains an isocyanate compound and a compound having a thioether bond and a hydroxyl group in the same molecule. Silver-plated body.