JP2003313685A - Composition for preventing silver or silver plating, or silver alloy or silver alloy plating from discoloring or corroding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop an effective composition for inhibiting a silver or silver- plated product, or a silver alloy or silver-alloy-plated product from discoloring and/or corroding, to clean it without causing discoloration and/or the corrosion, or to retard the discoloration and/or the corrosion after treatment, and to develop a discoloration and/or corrosion inhibitor which shows the remarkable effect particularly on the silver alloy containing tin, zinc, copper, indium, palladium or the like. <P>SOLUTION: This composition includes α-diketone capable of having a keto- enol tautomerism structure, or salts thereof. When the silver or silver-plated product or the silver alloy or silver alloy-plated product is cleaned with a cleaner containing the composition in a cleaning step, the discoloration or the corrosion is effectively inhibited. The surface discoloration and/or corrosion of the silver or silver-plated product or the silver alloy or silver alloy-plated product, particularly the product of the silver alloy containing tin, zinc, copper, indium, palladium or the like, is effectively inhibited thereafter by being immersed in a solution containing the composition. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal surface treatment technique, and more particularly to prevention of discoloration / corrosion and cleaning of the surface of silver or silver plating or silver alloy or silver alloy plating.

[0002]

2. Description of the Related Art Silver and silver alloys and their plating are excellent in electrical resistance, contact resistance, high frequency characteristics, solderability, sliding characteristics, appearance, etc. Moreover, since silver is a safe metal, tableware, It is widely used not only in ornaments, jewelry and dentures, but also industrially for forming sliding parts and electric circuits. On the other hand, it is well known that silver is a metal that easily causes discoloration or corrosion depending on the environment, and that it is remarkable especially in an environment containing a compound containing sulfur. In order to prevent or suppress such discoloration / corrosion, benzotriazole, 2-mercaptobenzothiazole, thiophenol, lauryl mercaptan, thionaphthol, thioanthranol, etc.,
Various discoloration and corrosion inhibitors are effective and used.
However, the conventional discoloration / corrosion inhibitors as described above are extremely incomplete in a harsh cleaning environment or a corrosive environment even though they have a certain effect, and a more effective discoloration / corrosion inhibitor is required. Was there. Furthermore, in the case of alloys, the conventional compounds as exemplified above do not show a remarkable discoloration / corrosion prevention effect, and particularly for alloys of tin, zinc, copper, indium, palladium, etc. and silver. It wasn't quite as effective.

[0003]

Problems to be Solved by the Invention It is possible to suppress discoloration / corrosion of silver or silver plated or silver alloy or silver alloy plated products, and to wash without discoloration or corrosion, or to discolor after treatment. It was a research subject of the present invention to develop a composition which can suppress corrosion and which is extremely effective and cannot be obtained by conventional discoloration / corrosion inhibitors. In particular, it was a research subject of the present invention to develop a composition having a high effect of preventing discoloration / corrosion with respect to a silver alloy containing tin, zinc, copper, indium, palladium or the like.

[0004]

DISCLOSURE OF THE INVENTION The inventors of the present invention have found that silver or silver if washed with a detergent containing an α-diketone or a salt thereof capable of having a keto-enol tautomeric structure in a solution. Plating or silver alloy or silver alloy plated products, especially discoloration and corrosion during washing of silver alloy containing tin, zinc, copper, indium, palladium, etc. can be suppressed very effectively, and keto-enol in solution By being immersed in a solution containing an α-diketone or a salt thereof capable of having a tautomeric structure, the subsequent discoloration / corrosion of the surface of silver or silver-plated or silver alloy or silver-alloy plated product can be suppressed very effectively. And has solved the problem of the present application.

The subject of the present invention is therefore: silver or silver plating containing one or more α-diketones or salts thereof which are capable of taking a keto-enol tautomeric structure when dissolved in a solution or Composition for preventing discoloration / corrosion of silver alloy or silver alloy plating, especially tin, zinc,
Discoloration / corrosion inhibiting composition of silver alloy containing copper, indium, palladium, etc., and silver or silver plating or silver alloy or silver alloy plating product treated with the discoloration / corrosion inhibiting composition, or It is a part, that is, silver or silver plated or silver alloy or silver alloy plated tableware, ornaments, jewelry, dentures, electric / electronic circuits or electric / electronic circuit parts.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION That is, the composition for preventing discoloration / corrosion of silver or silver plating or silver alloy or silver alloy plating of the present invention is represented by the following general formula (1), (2), (3) or (4). 1) or 2 or more kinds of α-diketones or salts thereof capable of having a keto-enol tautomeric structure selected from the above. General formula (1)

[Chemical 1] [Here, X1 represents oxygen or nitrogen. Y1 does not exist when X is oxygen, and is a C1 to C2 alkyl group, or C1 to C2 in which a part of hydrogen is substituted with halogen or a hydroxyl group.
Represents an alkyl group of 0, a C1 to C20 alkoxy group, or an unsubstituted or substituted aryl group. Y2, Y3 and Y
4 is hydrogen, a hydroxyl group, a C1 to C20 alkyl group, or C1 to C20 in which a part of hydrogen is replaced by a halogen or a hydroxyl group.
Represents an alkyl group, a C1-C20 alkoxy group, or an unsubstituted or substituted aryl group, and may be the same or different. Further, hydrogen of a hydroxyl group adjacent to a ketone may be replaced with an alkali metal, an alkaline earth metal, ammonia or an organic amine to form a salt. ] A cyclic α-diketone capable of having a keto-enol tautomeric structure represented by the general formula (2)

[Chemical 2] [Here, Y5, Y6 and Y7 are hydrogen, hydroxyl group, C1
To C20 alkyl group, C1 to C20 alkyl group in which a part of hydrogen is substituted with halogen or hydroxyl group, C1 to C2
0 represents an alkoxy group or an unsubstituted or substituted aryl group, which may be the same or different. Further, hydrogen of a hydroxyl group adjacent to a ketone may be replaced with an alkali metal, an alkaline earth metal, ammonia or an organic amine to form a salt. ] A cyclic α-diketone capable of having a keto-enol tautomeric structure represented by the general formula (3)

[Chemical 3] [Here, the hydrogen of the hydroxyl group may be replaced with an alkali metal, an alkaline earth metal, ammonia or an organic amine to form a salt. ] A cyclic α-diketone capable of having a keto-enol tautomeric structure represented by the following or a salt thereof, the general formula (4)

[Chemical 4] [Here, X2 represents carbon or oxygen. Y8 is X2
Does not exist when is oxygen, hydrogen, a C1 to C20 alkyl group, a C1 to C20 alkyl group in which a part of hydrogen is substituted with halogen or a hydroxyl group, a C1 to C20 alkoxy group, or an unsubstituted or substituted aryl group. Represents Y9 and Y10 represent hydrogen, a C1 to C20 alkyl group, a C1 to C20 alkyl group in which a part of hydrogen is substituted with halogen or a hydroxyl group, a C1 to C20 alkoxy group, or an unsubstituted or substituted aryl group, It may be the same or different. Further, hydrogen of a hydroxyl group adjacent to a ketone may be replaced with an alkali metal, an alkaline earth metal, ammonia or an organic amine to form a salt. ] The cyclic (alpha) -diketone which can take the keto-enol tautomeric structure represented by this.

As the above-mentioned salt of α-diketone, an inorganic or (and) organic salt is used. As the inorganic salt, a salt of an alkali metal or an alkaline earth metal or a salt of ammonia is preferably used. And specifically,
Potassium, sodium and ammonium salts are preferably used, and more preferably sodium salts are used.

Suitable organic salts include onium salts of organic amines such as oxazole, thiazole, indazole, imidazole, triazole, tetrazole, oxazoline, thiazoline,
Imidazoline, pyrrole, indole, pyrrolidine, pyrrolidone, benzoxazole, benzothiazole, benzindazole, benzimidazole, benzotriazole, benzotetrazole, pyridine, pyrazine, pyrimidine, piperidine, piperazine, morpholine, quinoline, or pyridazine, or derivatives thereof. One type or two or more types of the onium salts of are preferably used.

The discoloration / corrosion preventive composition of the present invention is used for the discoloration / corrosion prevention treatment of silver or silver-plated products or silver alloys or silver alloy-plated products, and water or an organic solvent such as alcohol or various cellosolves. Alternatively, it is carried out by dipping or applying the product in the form of a solution of a mixture thereof. Therefore, it is needless to say that the discoloration / corrosion preventing composition may be supplied in the form of such a solution, but the composition is provided in the form of a tablet or granular powder for production / transportation / storage, and prior to treatment. The composition for preventing discoloration / corrosion of tablets or granular powder may be dissolved and subjected to treatment.

The amount of the α-diketone or a salt thereof used is preferably 0.001 g / L to 200 g / L, more preferably, when expressed as the concentration when the solution is used in the above treatment. Is 0.1 g / L to 100 g / L
The range of is used.

The discoloration / corrosion preventing composition of the present invention is a composition for use in preventing discoloration / corrosion of the surface of silver or silver plating or silver alloy or silver alloy plating, and is immersed in a solution of the composition. Therefore, it is used for suppressing the subsequent discoloration of silver or silver plating or silver alloy or silver alloy plating surface. It is often encountered that silver or silver plating or a silver alloy or silver alloy plated surface is discolored, but it is cleaned with a cleaning agent containing the discoloration / corrosion preventing composition of the present invention. By doing so, discoloration during cleaning can be suppressed and discoloration after cleaning can be suppressed.

From the viewpoint of components, the object of treatment with the discoloration / corrosion preventing composition of the present invention is a part or a product containing silver or silver plating or a silver alloy or silver alloy plating. Examples of silver alloy plating include atomic numbers 26 to 33, 44 to 51 excluding silver, 76 to 83, and binary or multi-element alloys of aluminum, magnesium, titanium, etc. and silver. Specifically, the elements having atomic numbers 26 to 33 are iron, cobalt, nickel, copper, zinc, gallium, germanium, and arsenic, and the elements 44 to 51 excluding silver are ruthenium and rhodium. , Palladium, cadmium, indium,
Tin and antimony, and elements 76 to 83 are osmium, iridium, platinum, gold, mercury, thallium, lead,
Bismuth. Of these, arsenic, cadmium, mercury,
It is not preferable to use alloys containing thallium and lead from the viewpoint of their own toxicity, but for example, alloys containing lead may have to be used for special applications because of their sliding characteristics. -The discoloration / corrosion preventing composition of the present application may be used for these alloys depending on the purpose.

Among these silver alloys, tin, zinc, copper,
Conventionally, it has been difficult to prevent discoloration and corrosion of alloys containing indium or palladium. Various alloys are used to obtain strength, hardness, color tone, and other desired properties, but care must always be taken to promote corrosion and discoloration due to local cell action of dissimilar metals. In the case of a silver alloy containing tin, zinc, copper, or indium, which is a base metal than silver, those base metals are easily oxidized,
Further, when palladium, which is a noble metal, is included, silver may be more likely to undergo discoloration due to local battery action. The corrosion inhibitor could not exert its effect sufficiently.

On the other hand, when the α-diketone which can have the keto-enol tautomeric structure of the present invention or a salt thereof is contained, not only silver but also silver containing the above-exemplified metals. Since the alloys also have a very remarkable discoloration / corrosion preventing effect, they are particularly suitable for use in tableware, ornaments, jewelry, dentures and the like in which these alloys are used. In particular, it is particularly preferably used for a silver alloy containing tin and zinc, which has little effect with conventional discoloration / corrosion inhibitors.

From the viewpoint of the component concentration of the silver alloy, the content of the alloy component in which the composition of the present invention shows a particularly remarkable effect as compared with the conventional discoloration / corrosion inhibitors is tin or (and ) In the case of zinc, 1% or more for each 4
A remarkable effect is recognized in the range of 0% or less, and more preferably 10% or more and 20% or less.

When the alloy component is copper, the content rate which exhibits a particularly remarkable effect as compared with conventional discoloration / corrosion inhibitors is 0.1%.
A remarkable effect is recognized in the range of 50% or less, and more preferably 1% or more and 20% or less.

When the alloy component is indium, the content ratio which exhibits a particularly remarkable effect as compared with the conventional discoloration / corrosion inhibitors is
A remarkable effect is recognized in the range of 1% or more and 40% or less, and more preferably the range of 5% or more and 30% or less.

When the alloy component is palladium, the content ratio which exhibits a particularly remarkable effect as compared with conventional discoloration / corrosion inhibitors is
A remarkable effect is recognized in the range of 1% or more and 40% or less, and more preferably the range of 5% or more and 30% or less.

That is, from the viewpoint of the types of parts and products, tableware, ornaments, jewelry, dentures or electric / electronic circuits and electric / electronic circuit parts, etc. containing silver or silver plating or silver alloy or silver alloy plating, etc. Yes, among them, tableware, decorations,
It is more preferably used for silver alloy products such as jewelry and dentures, and particularly has a remarkable effect in preventing discoloration and corrosion during cleaning of dentures.

The discoloration / corrosion preventing composition of the present invention comprises water,
Alternatively, it can be used as a solution of an organic solvent such as alcohol or various cellosolves, or a mixture thereof, but it is more preferably used as an aqueous solution from the viewpoint of safety. When used as an aqueous solution, it can be suitably used in a wide range of strong acidity to strong alkalinity depending on the application and purpose, but due to safety in use and consideration for the environment, pH
It is preferably used in the range of 3 to pH 11. The treatment method most commonly uses a method of immersing the product in those solutions, but a method of applying the product can also be used.

The composition for preventing discoloration / corrosion of silver or silver plating or silver alloy or silver alloy plating of the present invention imparts or improves cleaning power so that the processing solution sufficiently wets the surface of the object to be processed. For this purpose, one or more kinds of surfactants can be further contained.

As the surfactant that can be further contained, any of known nonionic surfactants, cationic surfactants, anionic surfactants and amphoteric surfactants can be used alone or in combination. However, the following surfactants and the like can be given as examples.

Suitable nonionic surfactants include polyoxyalkylene alkyl ethers (or esters), polyoxyalkylene phenyl (or alkylphenyl) ethers, polyoxyalkylene naphthyl (or alkyl naphthyl) ethers, polyoxyalkylenes. Styrenated phenyl ether (or polyoxyalkylene styrenated phenyl ether in which a polyoxyalkylene chain is further added to the phenyl group), polyoxyalkylene bisphenol ether, polyoxyethylene polyoxypropylene block polymer, polyoxyalkylene sorbitan fatty acid ester, poly Oxyalkylene sorbit fatty acid ester, polyethylene glycol fatty acid ester, polyoxyalkylene glycerin fatty acid ester, poly Xylene alkylene alkylamine,
Polyoxyalkylene condensate adduct of ethylenediamine, polyoxyalkylene fatty acid amide, polyoxyalkylene castor (or hydrogenated castor oil) oil, polyoxyalkylene alkylphenyl formalin condensate, glycerin (or polyglycerin) fatty acid ester, pentaerythritol fatty acid ester , Sorbitan mono (sesqui,
Tri) fatty acid ester, higher fatty acid mono (di) ethanolamide, alkyl alkylolamide, oxyethylene alkylamine and the like are included.

Suitable cationic surfactants include tetra-lower alkyl ammonium halides, alkyl trimethyl ammonium halides, hydroxyethyl alkyl imidazolines, polyoxyethylene alkyl methyl ammonium halides, alkyl benzalkonium halides, dialkyl dimethyl ammonium halides.
Examples include alkyldimethylbenzylammonium halide, alkylamine hydrochloride, alkylamine acetate, alkylamine oleate, alkylaminoethylglycine, alkylpyridinium halide and the like. Further, the cationic surfactant may be blended as a bactericidal component.

Suitable anionic surfactants include alkyl (or formalin condensate) -β-naphthalene sulfonic acid (salt), fatty acid soap-based surfactant, alkyl sulfonate, α-olefin sulfonate. , Alkyl benzene sulfonate, alkyl (or alkoxy) naphthalene sulfonate, alkyl diphenyl ether disulfonate, alkyl ether sulfonate,
Alkyl sulfate ester salt, polyoxyethylene alkyl ether sulfate ester salt, polyoxyethylene alkylphenol ether sulfate ester salt, higher alcohol phosphate monoester salt, polyoxyalkylene alkyl ether phosphate (salt), polyoxyalkylene alkylphenyl ether phosphate Salt, polyoxyalkylene phenyl ether phosphate, polyoxyethylene alkyl ether acetate, alkanoyl sarcosine, alkanoyl sarcosinate, alkanoylmethylalanine salt, N-acylsulfocarboxylate, alkylsulfoacetate, acylmethyl tauric acid Salt, alkyl fatty acid glycerin sulfate, hardened coconut oil fatty acid glyceryl sulfate, alkyl sulfocarboxylic acid ester salt, alkyl sulfosuccinate, dialky Sulfosuccinates, alkyl polyoxyethylene sulfosuccinates, amido polyoxyethylene sulfosuccinate, there is sulfosuccinic acid mono oleyl amide salt. The above-mentioned salts include alkali metal salts, triethanolamine salts, ammonium salts and the like.

The preferred amphoteric surfactant is 2
-Alkyl-N-carboxymethyl (or ethyl) -N
-Hydroxyethyl (or methyl) imidazolinium betaine, 2-alkyl-N-carboxymethyl (or ethyl) -N-carboxymethyloxyethyl imidazolinium betaine, 2-alkyl-N-carboxymethyl (or ethyl) -N -Hydroxyethyl (or methyl)
Imidazoline, dimethylalkyl betaine, N-alkyl-β-aminopropionic acid (or its salt), alkyl (poly) aminoethylglycine, N-alkyl-N-methyl-β-alanine (or its salt), fatty acid amide propyldimethyl Aminoacetic acid betaine, etc. The above-mentioned salts include alkali metal salts, triethanolamine salts, ammonium salts and the like.

The amount of these surfactants to be used may be in accordance with the usual formulation of the surfactant and is appropriately selected depending on the type. Generally, it is generally 0 when expressed as the concentration of the solution used for the treatment. The range of 0.001 g / L to 200 g / L is used, and more preferably 0.01 g / L to 50 g / L.
A range of L is used.

The discoloration / corrosion preventive composition of the present invention further comprises discoloration-removing components, pH adjusters, foaming agents, bleaching agents / oxidizing agents, bleaching-activating ingredients, tartar-dissolving ingredients, disinfectants / bactericides.
One or more of a bactericidal component, a soil redeposition preventive agent, a protein / lipolytic enzyme, a wetting agent, a preservative, a sweetener, a fragrance, an excipient, or a component forming a resin coating film may be contained. it can. Furthermore, the discoloration / corrosion prevention composition of the present invention may be used in combination with other known discoloration inhibitors and corrosion inhibitors, and among them, for example, by combining with iodine ions, the discoloration / corrosion prevention effect can be obtained. It can be increased further.

As the discoloration-removing component that can be further contained, known discoloration-removing compounds are appropriately used alone or in combination. As an example, thiosulfate ion, thiocyanate ion, sulfite ion, bisulfite ion, meta Bisulfite ion, thiourea or its derivative, hydantoin compound, succinimide or its derivative, alkaline earth metal salt, ammonium salt or organic amine salt, cystine, cysteine, thioacetamide, penicylamine,
Rhodamine, a xanthate ion, etc. are mentioned.

The amount of these discoloration-removing components and the like used is not particularly limited by setting a critical point, but the amount necessary and sufficient for these compounds to exhibit discoloration / corrosion inhibiting action, that is, the amount of the solution used for the treatment. When expressed as the concentration at that time, the range of about 0.001 g / L to 200 g / L is used, and more preferably the range of 0.01 g / L to 50 g / L is used.

As the pH adjusting agent which can be further contained, known pH adjusting agents are appropriately used alone or in combination. As an example, phosphoric acid, acetic acid, boric acid, citric acid, tartaric acid and the like are respectively sodium and potassium. Alternatively, ammonium salts and the like can be mentioned, and in the case of polybasic acid, acidic salts containing hydrogen ions and the like can be mentioned.

As the foaming agent which can be further contained, a known foaming agent is appropriately used alone or in combination, and examples thereof include sodium, potassium, lithium, or rubidium carbonate or hydrogen carbonate. To be

As the bleaching agent / oxidizing agent which can be further contained, known bleaching components are appropriately used alone or in combination, and as an example, sodium peroxide, sodium persulfate, sodium percarbonate, isocyanurate. , Sodium hypochlorite, sulfite, peroxysulfate / potassium hydrogen, sodium perborate and the like.

As the bleaching activating component that can be further contained, known bleaching activating components are appropriately used alone or in combination. As an example, an N-acylated amine,
N-acylated diamine, N-acylated amide, glycolylurea, acyloxybenzene sulfonate, acylated sugar, sugar derivative, active carboxylic acid ester, active carboxamide, carboxylic acid anhydride, lactone, acylal,
Acyl lactam, alkane nitrile, arene nitrile and the like can be mentioned.

As the tartar-dissolving component that can be further contained, known tartar-dissolving components are appropriately used alone or in combination. As an example, aminopolycarboxylic acid or a salt thereof, fruit acid such as citric acid, and sulfamic acid. And other organic acids.

As the disinfectant / bactericidal / bactericidal component which can be further contained, known bactericidal / bactericidal components are appropriately used alone or in combination. As an example, chlorhexidine digluconate, hexetidine, alexidine, Examples thereof include tetraammonium antibacterial compounds.

As the stain redeposition preventing agent that can be further contained, known stain redeposition preventing agents are appropriately used alone or in combination. As an example, carboxymethyl cellulose, polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone and the like are used. Can be mentioned.

As the protein / lipolytic enzyme which can be further contained, known protein / lipolytic enzymes are appropriately used alone or in combination. As an example, cellulase,
Examples include amylase, protease, alkaline protease, dextranase, glucanase, β-1,3-glucanase, mutanase, esterase, lipase, cellulase, inulase, papain and the like.

As the wetting agent which can be further contained, known wetting agents are appropriately used alone or in combination, and examples thereof include glycerin, sorbitol, propylene glycol, 1,3-butylene glycol and polyethylene glycol. To be

As the preservatives that can be further contained, known preservatives are appropriately used alone or in combination, and examples thereof include paraoxybenzoic acid ester and sodium benzoate.

As the sweetener that can be further contained, known sweeteners are appropriately used alone or in combination, and examples thereof include saccharin sodium, stevioside, neohespiridyl hydrochalcone, glycyrrhizin, thaumatin, perillartin and the like. .

Known fragrances may be used alone or in combination as the fragrance that can be further contained.
Examples include menthol, spearmint, cinnamon, wintergreen, peppermint and the like.

As the excipient that can be further contained, known excipients are appropriately used alone or in combination, and examples thereof include glycerin, maltitol, xylitol, propylene glycol and the like.

As a component for forming a resin coating film which can be further contained, known resin coating film forming components are appropriately used alone or in combination, and examples thereof include silicone acrylic resin and silicone alkyd resin. .

[0045]

The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the scope of the present invention, but within the scope of the claims set forth for the above purposes. The composition and treatment conditions of the discoloration / corrosion prevention component are
It can be arbitrarily changed as appropriate.

Various samples were dipped and washed with the treatment liquids having the compositions shown in the following examples and comparative examples. The discoloration / corrosion prevention effect at that time was compared.

(Example 1) A was added to the following processing solution (IA).
As a result of immersing and cleaning an alloy plate of g / Sn / Zn (65/21/14) at room temperature for 8 hours, no discoloration was observed. Treatment liquid (IA) Chloranilic acid 10 g / L Polyoxyalkylene alkyl ether 0.5 g / L Potassium dihydrogen phosphate 5 g / L Polyethylene glycol 1 g / L

Comparative Example 1 A treatment liquid (IB) obtained by removing chloranilic acid from the treatment liquid (IA) was used in Example 1.
The same process was performed. When it was treated with the solution of (IB), the color changed drastically.

Example 2 An Ag / Sn / Zn (65/15/20) alloy plate was immersed in the following treatment liquid (II-A) for 8 hours at room temperature and washed, and no discoloration was observed. . Treatment liquid (II-A) Kojic acid 5 g / L Alkylpyridinium halide 5 g / L Sodium hydrogencarbonate 5 g / L Protease 1 g / L Potassium iodide 0.05 g / L

Comparative Example 2 A treatment liquid (II-) obtained by removing kojic acid and potassium iodide from the above treatment liquid (II-A).
The same treatment as in Example 2 was performed using B). (II-
When it was treated with the solution of B), the color changed drastically.

Example 3 The following processing solution (III-A)
As a result of immersing the alloy plate of Ag / Sn / Zn (65/21/14) in 8 hours at room temperature for washing, no discoloration was observed. Treatment liquid (III-A) Tetrahydroxy-1,4-quinone 0.5 g / L 2-alkyl-N-carboxymethyl (or ethyl) -N-hydroxyethyl (or methyl) imidazolinium betaine 10 g / L thiourea 0.5 g / L Glycerin 1 g / L

Comparative Example 3 The same treatment as in Example 3 was carried out using a treatment liquid (III-B) obtained by removing tetrahydroxy-1,4-quinone from the above treatment liquid (III-A). When it was treated with the solution of (III-B), the color changed significantly.

Example 4 As a result of immersing a pure silver plate in the following treatment liquid (IV-A) at room temperature for 3 hours and washing it, no discoloration was observed. Treatment liquid (IV-A) 3-Ethyl-2-hydroxy-2-cyclopentan-1-one natrium 0.05 g / L alkylbenzene sulfonate 5 g / L isocyanurate 5 g / L N-acylated amide 1 g / L

Comparative Example 4 3-Ethyl-2-hydroxy-2-cyclopentane-1 from the above treatment liquid (IV-A)
The same treatment as in Example 4 was performed using the treatment liquid (IV-B) from which -on sodium had been removed. When it was treated with the solution of (IV-B), the color changed violently.

Example 5 A discoloration was not observed as a result of immersing a printed circuit in which the substitution silver was plated on a copper foil in the following treatment liquid (VA) at room temperature for 20 minutes and washing. Treatment liquid (VA) 3-hydroxy-2-methyl-4-pyrone 20 g / L citric acid 5 g / L sodium benzoate 5 g / L menthol 0.1 g / L

(Comparative Example 5) From the above treatment liquid (VA), 3
The same treatment as in Example 5 was performed using the treatment liquid (VB) from which -hydroxy-2-methyl-4-pyrone was removed.
When it was treated with the solution of (V-B), the color changed violently.

Example 6 As a result of immersing an alloy plate of Ag / Sn / Zn (65/15/20) in the following treatment liquid (VI-A) at room temperature for 8 hours and washing it, no discoloration was observed. . Treatment liquid (VI-A) Calcium rhodizonate 2 g / L Alkyl polyoxyethylene sulfosuccinate 20 g / L Chlorhexidine digluconate 5 g / L Xylitol 1 g / L

Comparative Example 6 The same treatment as in Example 6 was carried out using a treatment liquid (VI-B) obtained by removing calcium rhodizonate from the above treatment liquid (VI-A). When it was treated with the solution of (VI-B), the color changed significantly.

Example 7 The following processing solution (VII-A)
Nishofu Dental Silver Alloy Super Silver (Ag / Sn /
Zn / others = 73/8/16/3) alloy lumps were immersed and washed at room temperature for 8 hours, and no discoloration was observed. Treatment liquid (VII-A) 3-Methyl-1,2-cyclopentanedione ammonium 6 g / L Polyoxyalkylene castor oil 2 g / L Acyloxybenzenesulfonate 5 g / L Stevioside 1 g / L

Comparative Example 7 The same treatment as in Example 7 was carried out using a treatment liquid (VII-B) obtained by removing 3-methyl-1,2-cyclopentanedione ammonium from the above treatment liquid (VII-A). went. When it was treated with the solution of (VII-B), the color changed drastically.

Example 8 The following processing solution (VIII-
As a result of immersing the silver-plated tableware in A) for 2 hours at room temperature and washing, no discoloration was observed. Treatment liquid (VIII-A) 3-Hydroxy-1,2-dimethyl-4 (1H) -pyridone pyridinium 2 g / L cysteine 10 g / L dextranase 5 g / L sorbitol 1 g / L

(Comparative Example 8) The above treatment liquid (VIII-A)
To 3-hydroxy-1,2-dimethyl-4 (1H)-
Treatment liquid without pyridonepyridinium (VIII-B)
Was used to perform the same treatment as in Example 8. (VIII-
When it was treated with the solution of B), the color changed drastically.

Example 9 An alloy lump of Ag / Pd / In / Cu (51/25/20/4) was immersed in the following treatment liquid (IX-A) at room temperature for 4 hours and washed, and as a result, almost all discoloration occurred. Was not recognized. Treatment liquid (IX-A) 2,5-dihydroxy-1,4-benzoquinone 10 g / L alkylbenzalkonium halide 30 g / L potassium sodium tartrate 5 g / L papain 1 g / L

Comparative Example 9 The same treatment as in Example 9 was carried out using a treatment liquid (IX-B) obtained by removing 2,5-dihydroxy-1,4-benzoquinone from the above treatment liquid (IX-A). It was When it was treated with the solution of (IX-B), the color changed drastically.

Comparative Example 10 In place of chloranilic acid in the treatment liquid (IA) used in Example 1, benzotriazole, which has been conventionally used for preventing discoloration and corrosion of silver, 2-
Each of mercaptobenzothiazole, thiophenol, lauryl mercaptan, thionaphthol, and thioanthranol was added in the same manner as in Example 1.
An alloy plate of g / Sn / Zn (65/21/14) was immersed and washed at room temperature for 8 hours. The color changed significantly when any of the compounds was replaced. However, since each compound was not completely dissolved, the test was carried out in the state where there was an undissolved amount of these compounds.

[0066]

The composition of the present invention for preventing discoloration / corrosion of silver or silver plating, or silver alloy or silver alloy plating, discolors the product of silver or silver alloy (or their plating) even in a severe washing environment. -It is possible to suppress corrosion and perform cleaning without causing discoloration or corrosion, or to suppress discoloration or corrosion after treatment with a very remarkable effect. In particular, it shows a remarkable effect even on silver alloys containing tin, zinc, copper, indium, palladium, etc., which had little effect with conventional anti-tarnish agents. You can now be exposed to the conditions.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akihiro Sagawa             8 shares of 21 Futami, Futami-cho, Akashi-shi, Hyogo             Ceremony company Daiwa Chemical Research Institute F-term (reference) 4K062 AA03 BC21 FA09 FA20 GA01

Claims (16)

[Claims] 1. The following general formulas (1) to (4): general formula (1) [Here, X1 represents oxygen or nitrogen. Y1 does not exist when X is oxygen, and is a C1 to C2 alkyl group, or C1 to C2 in which a part of hydrogen is substituted with halogen or a hydroxyl group.
Represents an alkyl group of 0, a C1 to C20 alkoxy group, or an unsubstituted or substituted aryl group. Y2, Y3 and Y
4 is hydrogen, a hydroxyl group, a C1 to C20 alkyl group, or C1 to C20 in which a part of hydrogen is replaced by a halogen or a hydroxyl group.
Represents an alkyl group, a C1-C20 alkoxy group, or an unsubstituted or substituted aryl group, and may be the same or different. Further, hydrogen of a hydroxyl group adjacent to a ketone may be replaced with an alkali metal, an alkaline earth metal, ammonia or an organic amine to form a salt. ] A cyclic α-diketone capable of having a keto-enol tautomeric structure represented by the following general formula (2): [Here, Y5, Y6 and Y7 are hydrogen, hydroxyl group, C1
To C20 alkyl group, C1 to C20 alkyl group in which a part of hydrogen is substituted with halogen or hydroxyl group, C1 to C2
0 represents an alkoxy group or an unsubstituted or substituted aryl group, which may be the same or different. Further, hydrogen of a hydroxyl group adjacent to a ketone may be replaced with an alkali metal, an alkaline earth metal, ammonia or an organic amine to form a salt. ] A cyclic α-diketone capable of having a keto-enol tautomeric structure represented by the following general formula (3): [Here, the hydrogen of the hydroxyl group may be replaced with an alkali metal, an alkaline earth metal, ammonia or an organic amine to form a salt. ] Cyclic α-diketone which can have a keto-enol tautomeric structure or a salt thereof, represented by the general formula (4): [Here, X2 represents carbon or oxygen. Y8 is X2
Does not exist when is oxygen, hydrogen, a C1 to C20 alkyl group, a C1 to C20 alkyl group in which a part of hydrogen is substituted with halogen or a hydroxyl group, a C1 to C20 alkoxy group, or an unsubstituted or substituted aryl group. Represents Y9 and Y10 represent hydrogen, a C1 to C20 alkyl group, a C1 to C20 alkyl group in which a part of hydrogen is substituted with halogen or a hydroxyl group, a C1 to C20 alkoxy group, or an unsubstituted or substituted aryl group, It may be the same or different. Further, hydrogen of a hydroxyl group adjacent to a ketone may be replaced with an alkali metal, an alkaline earth metal, ammonia or an organic amine to form a salt. ] Cyclic α-diketone capable of having a keto-enol tautomeric structure represented by: or silver or silver plating or silver alloy or silver alloy containing one or more selected from compounds represented by: or salts thereof. Composition for preventing discoloration and corrosion of plating. 2. The α-diketone or salt thereof capable of having the keto-enol tautomeric structure is 3-hydroxy-
2-methyl-4-pyrone, 3-hydroxy-1,2-dimethyl-4 (1H) -pyridone, 2,5-dihydroxy-1,4-benzoquinone, chloranilic acid, tetrahydroxy-1,4-quinone, rhodizone Acid, kojic acid, 2.5
-Dimethyl-4-hydroxy-3 (2H) -furanone,
3-methyl-1,2-cyclopentanedione, 3-ethyl-2-hydroxy-2-cyclopentan-1-one,
The discoloration / corrosion preventing composition according to claim 1, which is a salt or hydrate thereof substituted with an alkali metal, alkaline earth metal, ammonia or organic amine. 3. The discoloration according to claim 1 or 2, wherein the alloy is a silver alloy or a silver alloy plating film containing at least one metal selected from copper, tin, zinc, indium, and palladium. A composition for preventing corrosion. 4. The silver alloy or silver alloy plating film containing at least tin and zinc as the alloy.
The composition for preventing discoloration / corrosion according to any one of 1. 5. The silver alloy or silver alloy plating film according to claim 1, wherein the alloy contains one or two kinds of tin and / or zinc in a range of 1% or more and 40% or less, respectively. A composition for preventing discoloration / corrosion according to Crab. 6. The discoloration / corrosion prevention according to claim 1, wherein the alloy is a silver alloy or a silver alloy plating containing one or more selected from copper, indium, and palladium. Composition. 7. The alloy is a silver alloy containing copper in a range of 0.1% to 50% and indium is 1% to 40.
The discoloration / corrosion preventing composition according to any one of claims 1 to 6, which is any one of a silver alloy containing 1% or more and / or 40% or less of palladium. object. 8. The discoloration / corrosion preventing composition according to claim 1, wherein the alloy is a dental silver alloy. 9. The discoloration according to any one of claims 1 to 8, which further comprises one or more surfactants.
A composition for preventing corrosion. 10. A discoloration removing component, a pH adjusting agent, a foaming agent, a bleaching agent / oxidizing agent, a bleaching activating component, a tartar dissolving component, a disinfectant / bactericidal / sterilizing component, a stain redeposition preventing agent, a protein / The lipolytic enzyme, a wetting agent, a preservative, a sweetening agent, a flavoring agent, an excipient, or one or more kinds of components forming a resin coating film is contained, and any one of claims 1 to 9 is included. discoloration·
A composition for preventing corrosion. 11. The composition for preventing discoloration / corrosion according to claim 1, which is formed into a tablet, a granule, or a solution. 12. The discoloration / corrosion prevention composition according to claim 1, which is in the form of an aqueous solution having a pH adjusted to a range of 3 to 11. 13. A method for cleaning the surface of silver or silver plating or silver alloy or silver alloy plating.
A composition for preventing discoloration / corrosion according to any one of to 12. 14. The discoloration / corrosion prevention composition according to claim 1, wherein the cleaning of the surface of the alloy is cleaning of a denture. 15. Silver or silver-plated or silver alloy or silver-alloy-plated products or parts treated with the discoloration / corrosion preventing composition according to any one of claims 1 to 14. 16. Products or parts treated with the composition for preventing discoloration / corrosion are silver or silver-plated or silver alloy or silver-alloy plated tableware, ornaments, jewellery, dentures, electric / electronic circuits. The product or component according to claim 15, which is an electric / electronic circuit component.