WO2000011240A1 - Detergents for metal good and method of cleansing metal good with the same - Google Patents

Abstract

A detergent for silverware which comprises a weak acid and a compound capable of forming a complex salt containing silver, has a detergency of 80 or higher as determined through 45-sec immersion of silver blackened with sodium polysulfide, and optionally contains at least one additive selected from the group consisting of a deodorant, a rust preventive, and a detergent for oils. It preferably further contains an ampholytic surfactant. The silverware detergent is safe, odorless, and chemically stable and can be stored over long. When the detergent is used for cleansing silverware, the sulfide film adherent to the silverware surface can be easily dissolved away. A detergent for metal goods is also disclosed which comprises a weak acid and a compound capable of forming a complex salt containing a metal other than silver. The detergent for metal goods is safe, odorless, and chemically stable and can be stored over long. When the detergent is used for cleansing a metal good, the rust, smear, etc. adherent to the surface thereof can be easily dissolved away.

Description

 Description Metallic product cleaning agent and metal product cleaning method using the same

 The present invention relates to a metal product detergent and a method for cleaning metal products using the same, and more particularly, to a method for cleaning silver products such as various silver tableware (Western tableware) and jewelry. Silver cleaner and method of cleaning silver using it, and metals other than silver, such as copper, brass (brass), nigel, tin, gold, platinum group, lead, bismuth, antimony Metal products cleaning agents suitable for cleaning various metal products such as precious metals and jewelry, including at least one metal (alloy) selected from the group consisting of: and cleaning of the above metal products using the same. It is about the method. Background art

 Traditionally, using the beautiful shine unique to silver, for example, various silver tableware (Western tableware) such as dishes, pots, spoons, knives and forks, jewelry such as accessories and cups, etc. Silver products are widely used. However, silver reacts with sulfur dioxide and hydrogen sulfide in the air, that is, undergoes sulfurization corrosion, and easily forms a silver sulfide coating (sulfide coating) on its surface. Therefore, when used for a long period of time, the above silver products turn yellow or black due to the formation of a sulfide film.

Therefore, various silver detergents for cleaning silver products are available on the market to remove the sulfide film formed on the surface of the silver products and restore the beautiful shine unique to silver. Have been. For example, silverware detergents containing sulfuric acid as an active ingredient are known. The silverware detergent is removed by dissolving the sulfide coating.

 However, the above-mentioned conventional silver product detergent contains sulfuric acid, which is a deleterious substance, and therefore has a high risk. Further, when used, it gives off odors such as a sulfur odor and an irritating odor, so that the cleaning work is painful. It has a problem that it is unsuitable for use in ordinary households. In addition, since sulfuric acid is a strong acid, if the silver product is left immersed for a long time, for example, away from the place, the silver product may be excessively washed and may damage the surface of the silver product. Furthermore, if the used silverware cleaner adheres to the hands, the hands are dyed black by the silver dissolved in the silverware cleaner. In addition, since the active ingredients other than sulfuric acid contained in the silver product detergent are easily decomposed by the sulfuric acid, the silver product detergent tends to deteriorate due to, for example, precipitation during distribution or storage.

 Therefore, a silver product detergent suitable for use in ordinary households, that is, the silver product can be obtained by simply immersing the silver product, or by immersing and then lightly rubbing the silver product. There is a need for a silver product detergent that can dissolve and remove the sulfide film on the surface, is safe and odorless, is chemically stable, and can be stored for a long time.

Conventionally, metal products containing metals other than silver, such as noble metals and jewelry, have been used to remove dirt and the like formed on the surface of various metal products. Polishing is performed. However, in general, polishing a metal product with an abrasive requires a great deal of effort, and polishing the metal product with an abrasive results in very fine scratches being formed on the surface. As the polishing is repeated, the beautiful glow of the metal is gradually lost. Therefore, in order to regain the beautiful shine unique to metal, various metal product cleaning agents for cleaning various metal products have been proposed. For example, Japanese Unexamined Patent Publication No. Heisei 4 214884 (published on Aug. 5, 1992) discloses a solid “cleaning agent for precious metals and jewelry” containing a carbonate and an organic acid. Is disclosed. -The cleaning agent for metal products gives carbon dioxide gas to give fine vibrations to precious metals and jewelry, and enhances the cleaning ability. Also, for example, Japanese Patent Application Laid-Open No. 8-225966 (published on September 3, 1996) contains a strong acid such as hydrochloric acid or nitric acid and an additive such as a benzothiazole compound. A "chemical polishing solution for metals" suitable for iron-gel systems is disclosed. The polishing liquid is used while being heated to 96 ° C. or more.

 However, the above-mentioned conventional cleaning products for metal products generate carbon dioxide gas, so that a large amount of metal products need to be cleaned, for example, by paying attention to ventilation and paying attention so that the cleaning products do not overflow from the cleaning tank. If the metal product has a concave portion, carbon dioxide gas accumulates in the concave portion, and the portion may not be sufficiently cleaned. In addition, it takes a long time to clean (more than 5 minutes), and at the end of the generation of carbon dioxide gas, the cleaning performance is extremely reduced. Therefore, it is difficult to use metal product cleaning agents repeatedly. is there. In addition, the above-mentioned conventional cleaning products for metal products swell (increase in volume) as they absorb moisture, and their cleaning ability is reduced, eventually losing their effectiveness. It is necessary to take measures to do this.

In addition, the above-mentioned conventional polishing liquid must be used in a state where it is heated to a high temperature, so that it is extremely dangerous. Further, since a irritating odor is generated at the time of use, the cleaning work is painful, and the general household polishing liquid is used. Not suitable for use with There is a problem. In addition, since the surface of the metal product is dissolved and washed using a strong acid, if the metal product is left immersed for a long time, for example, by leaving the place, the metal product is excessively washed, The product surface may be damaged. In addition, it takes time to process the polishing liquid after use. In addition, since the active ingredient other than the strong acid contained in the polishing liquid is easily decomposed by the strong acid, the polishing liquid is liable to be deteriorated due to, for example, precipitation during distribution or storage.

 For example, Japanese Patent Laid-Open Publication No. Sho 51-13808 (published on February 3, 1976) discloses that the gas generated inside the boiler or inside the reactor that causes troubles such as failures A "scale cleaner containing iron and copper" has been disclosed to eliminate the sales promotion, and is disclosed in Japanese Patent Application Laid-Open No. 55-114,966 (published on September 3, 1990). ) Discloses a "method for cleaning copper-containing scales" in which promotion is removed with an acid containing formic acid. However, these cleaning agents only remove 鲭 simply and are not suitable for cleaning various metal products such as precious metals and jewelry. Furthermore, a detergent containing formic acid has a low reaction rate, has a strong irritating odor, and involves dangers such as formation of blisters at the spot when the skin is accidentally touched. In addition, depending on the conditions at the time of use, formic acid acts as a reducing agent, which has the disadvantage that the metal dissolved in the cleaning agent may redeposit and contaminate the surface of metal products. .

 Also, Japanese Patent Application Laid-Open No. 56-41389 (published on April 18, 1981)

) Discloses a "fireproofing agent" for forming a phosphate protective film on the surface of a steel product. However, since the heat-resistant agent forms a heat-resistant film on the surface of the product, it is not suitable for cleaning various metal products such as precious metals and jewelry, which must have beautiful luster unique to the metal. Therefore, a metal product detergent suitable for use in ordinary households, that is, various metal products such as precious metals and jewelry are immersed or subjected to simple treatment such as rubbing lightly after immersion. Alone, it can dissolve and remove dirt and the like on the surface of the metal product, and furthermore, it is safe and odorless, yet it is chemically stable and can be stored for a long time. There is a need for metal product cleaners for cleaning metal products containing metals other than silver. The present invention has been made in view of the above-mentioned problems of the conventional silver product detergent and the above-mentioned problems of the conventional metal product detergent for cleaning metal products containing metals other than silver. Is able to dissolve and remove the sulfide coating on the surface of silver products by simple treatment, and is safe, odorless, chemically stable, and can be stored for a long time. An object of the present invention is to provide a certain silver product detergent and a method for cleaning silver products using the same.

 A second object of the present invention is to dissolve and remove dirt and the like on the surface of a metal product containing a metal other than silver by performing a simple treatment, and furthermore, it is safe and odorless. An object of the present invention is to provide a metal product detergent which is chemically stable, can be stored for a long period of time, and a method for cleaning metal products using the same. Disclosure of the invention

In order to achieve the first object, the silver product detergent of the present invention comprises a complex-forming compound capable of forming a complex salt containing silver, a weak acid, and a polysulfide polymer. It is characterized in that the detergency after immersion for 45 seconds of silver blackened by using is 80 or more. While the above weak acids generate hydrogen ions. A complex-forming compound which is not easily decomposed and is preferably not a poison or a harmful substance and a chemically stable acid which does not generate an irritating odor at the time of use may be used. It is preferable because the reaction rate becomes higher, and it is desirable that the pKa is 4 or less in view of the aforementioned detergency. In the present invention, a weak acid is an acid other than a strong acid such as sulfuric acid, hydrochloric acid, or nitric acid, and has a buffering capacity (buffering action) in a certain region.

 Further, it is preferable that the above silver product detergent further contains at least one kind of additive selected from the group consisting of a deodorant, a deodorant and an oil detergent. Further, it is preferable that the silver product detergent contains an amphoteric surfactant as the additive.

Complex-forming compounds such as thiourea and weak acids such as sulfamic acid or amidosul furic acid are not poisons or deleterious substances, and do not generate a pungent odor when used. Further, the complex-forming compound is hardly decomposed by a weak acid such as sulfamic acid and phosphoric acid. The complexing compound reacts with the sulfide coating on the surface of the silver product, that is, silver sulfide to form a water-soluble, stable silver-containing complex salt, while forming an alloy containing silver or silver. (I.e., silver that has not undergone sulfidation corrosion) hardly reacts (it has a much lower reaction rate than silver sulfide). That is, the complex forming compound can selectively dissolve and remove only the sulfide film on the surface of the silver product. In addition, silver product detergent has a detergency of 80 or more after dipping for 45 seconds in silver that has been blackened using sodium polysulfide and has a higher cleaning performance than conventional detergents. Therefore, the silver product can be dissolved in the silver product surface by simply immersing the silver product in the silver product detergent or applying a simple treatment such as light rubbing after immersion. Can be removed. Therefore, according to the above configuration, For example, washing silverware with a silverware cleaner can restore the beautiful shine unique to silver without damaging the surface.

 This makes it possible to dissolve and remove the sulfide film on the surface of silver products with a simple treatment, and it is safe, odorless, chemically stable, and can be stored for a long time. Silver product cleaning agent can be provided.

 The silver product cleaning method of the present invention is characterized in that in order to achieve the first object, the silver product is cleaned using the above-mentioned silver product cleaning agent.

 This makes it possible to dissolve and remove the sulfide film on the silver product surface by simply performing a simple treatment with a silver product detergent that is chemically stable and can be stored for a long time. A safe and odorless method for cleaning silver products can be provided.

 In order to achieve the second object, the metal product detergent of the present invention is a metal product detergent for cleaning a metal product containing a metal other than silver, and forms a complex salt containing the metal. It is characterized by containing the obtained complex-forming compound and a weak acid.

 The complex forming compound is preferably thiourea. Further, the weak acid is preferably sulfamic acid.

Complex-forming compounds such as thiourea and weak acids such as sulfamic acid are not poisons or deleterious substances, and do not generate an irritating odor when used. Further, the complex-forming compound is difficult to be decomposed by a weak acid such as sulfamic acid and phosphoric acid. The complex-forming compound reacts with 錡 (eg, a metal oxide) on the surface of a metal product containing a metal other than silver to form a water-soluble, stable complex salt containing a metal other than silver. Metal other than silver on the surface ( In other words, it hardly reacts with non-corrosive metals other than silver (the reaction rate is extremely low as compared with (1)). Also, the weak acid reacts with metal on the surface of metal products containing metals other than silver (for example, oxides, hydroxides, basic carbonates, basic sulfates, etc., of metals other than silver) to form non-silver metals. While forming a water-soluble salt of the metal, it hardly reacts with metals other than silver on the surface (the reaction rate is extremely low as compared with 銪). That is, the complex-forming compound and the weak acid can selectively dissolve and remove only the surface of the metal product containing a metal other than silver. In addition, since metal product detergents are washed with both the complex forming compound and the weak acid, they have better cleaning ability than conventional detergents, and therefore, metal products containing metals other than silver can be used. After immersion or immersion in a metal product detergent, a simple treatment such as light rubbing can be applied to dissolve and remove dirt and the like on the metal product surface. Therefore, according to the configuration described above, by cleaning a metal product containing a metal other than silver using a metal product cleaning agent, it is possible to restore the beautiful shine unique to the metal without damaging the surface. .

 This makes it possible to dissolve and remove dirt and the like on the surface of metal products containing metals other than silver by simple processing, and is safe, odorless, and chemically stable. Thus, a metal product detergent that can be stored for a long time can be provided.

 In order to achieve the second object, the metal product cleaning method of the present invention is characterized in that a metal product containing a metal other than silver is cleaned using the metal product cleaning agent.

As a result, it is chemically stable and can be stored for a long period of time. It is possible to dissolve and remove dirt and the like on the surface of a metal product, and to provide a safe and odorless method for cleaning a metal product.

 Still other objects, features, and strengths of the present invention will be made clear by the description below. Also, the benefits of the present invention will become apparent in the following description.

BEST MODE FOR CARRYING OUT THE INVENTION

 The silver product detergent according to the present invention (hereinafter referred to as a silver detergent) contains a complex-forming compound capable of forming a complex salt containing silver, a weak acid, and is blackened using sodium polysulfide. The cleaning power after immersion of the silver for 45 seconds is 80 or more. Further, the silver detergent according to the present invention preferably further contains at least one additive selected from the group consisting of a deodorant, a deodorant, and an oil detergent. The silver detergent can take various forms such as, for example, liquid, paste, powder, solid, and aerosol. Alternatively, the silver detergent according to the present invention can be in a form in which a substrate such as paper or cloth is impregnated. Therefore, when the above-mentioned silver detergent is in a liquid form, it further contains a solvent such as water or a lower alcohol. In the following description, for convenience, the case where the form of the silver detergent is liquid will be described as an example.

The silver product to be cleaned by the silver cleaning agent may be made of pure silver or an alloy containing silver as a main component. Alternatively, the silver product may be a product in which silver or its alloy is used in a part of a decoration such as a pattern, or a product in which silver plating is applied. In short, the silver product to be washed with the silver detergent according to the present invention is a product containing silver as a main component. I just need. Specific examples of the silver products include various silver tableware (Western tableware) such as dish pots, spoons, knives and forks, and jewelry such as accessories and lipsticks. However, there is no particular limitation.

 The complex-forming compound contained in the silver detergent according to the present invention is a sulfurized film formed on the surface of a silver product, that is, a water-soluble stable silver-containing complex salt that reacts with silver sulfide. It is preferably a compound that is not a poisonous or deleterious substance and does not generate an irritating odor when used, and is not particularly limited, and a water-soluble organic compound is preferable. The water-soluble organic compound is not easily decomposed by a weak acid such as sulfamic acid and phosphoric acid. Also, the water-soluble organic compound hardly reacts with silver or an alloy containing silver (that is, silver that has not undergone sulfidation corrosion) (the reaction rate is much lower than that of silver sulfide). In other words, the complex-forming compound can selectively dissolve and remove only the sulfide film on the surface of the silver product. In the present invention, compounds that are sparingly soluble in water but soluble in acid are included in the water-soluble organic compounds.

Specific examples of the water-soluble organic compound include, for example, thioglycolic acid, methyl thioglycolate, ethyl thioglycolate, propyl thioglycolate, octyl thioglycolate, and 1-2-ethylglycol hexyl hexyl. Thiourea, its derivatives, such as thiourea, N-methylthiourea, N, N'-dimethylthiourea, 1,3-dimethylthiourea; and thioacetamide, 6-thioi. Nosin, 2 thioperacil, 4 thioperidine, ω — thiocaprolactam, 1, 4 — thioxan, 6 — thioguanine, thioctic acid, thioacetic acid, thiopropionic acid, 3, 3 '— thiodipropion acid, Sulfur-containing compounds such as 2,2'-thiogenol, thiosemicarbazide, thioproline, thioproperazine, thiomorpholin, and getyl thiolate; are exemplified, but not particularly limited. One of these water-soluble organic compounds may be used alone, or two or more thereof may be used in combination. Of the compounds exemplified above, thioglycolic acid and its esters, and thiourea and its derivatives are more preferable, and thiourea is particularly preferable because it is inexpensive.

The content of the complex-forming compound in the silver detergent, that is, the concentration in the washing solution such as an aqueous solution may be set according to the type of the complex-forming compound, the combination with a weak acid, and the like, and is particularly limited. However, it is preferred that the higher the reaction rate, the higher the reaction speed. The more preferable is the range of 1% to 30% by weight, and the more preferable is the range of 5% to 20% by weight. More preferably, it is particularly preferably in the range of 8% by weight to 12% by weight. In a silver detergent, i.e., a washing solution, the concentration of the complex-forming compound as an active ingredient is determined by forming a complex salt containing silver at the time of use, that is, by reacting the complex-forming compound with silver. It also decreases due to hydrolysis by weak acids and air oxidation. Therefore, if the concentration of the complex-forming compound is less than 1% by weight, the washing ability of the silver detergent may not be sufficiently exhibited, and the washing ability may be further reduced as the concentration decreases. On the other hand, if the concentration of the complex-forming compound exceeds 30% by weight, the viscosity of the washing solution increases, and the complex-forming compound may precipitate and not participate in the reaction with silver, which is uneconomical. is there. In addition, since the concentration of suspended solids in the cleaning solution may increase, the silver product surface may not be sufficiently cleaned. When two or more complex forming compounds are used in combination, the mixing ratio of these complex forming compounds is particularly limited. It is not something to be done.

 By the way, when the complex forming compound reacts with silver sulfide to form a complex salt containing silver, hydrogen sulfide is by-produced. However, since the sulfide film formed on the surface of the silver product is extremely thin, and hence the amount of silver sulfide that reacts is extremely small, the amount of by-product hydrogen sulfide is also extremely small. Therefore, there is practically no odor such as sulfur odor or pungent odor when using the silver detergent.

 The weak acid contained in the silver detergent according to the present invention, while generating hydrogen, is hard to decompose the complex-forming compound and is preferably not a toxic substance or a deleterious substance, and does not generate an irritating odor when used. Any acid that is chemically stable may be used, but a higher hydrogen ion concentration is preferable because the reaction rate is higher, and in view of the detergency, the pKa is preferably 4 or less. Desirable. Examples of the weak acid include, for example, citric acid, sulfamic acid, formic acid, acetic acid, propionic acid, tartaric acid, phosphoric acid, hypophosphorous acid, phosphorous acid, and the like. Examples thereof include, but are not limited to, phosphoric acid, metallic acid, and pyrrolic acid. These weak acids may be used alone or in combination of two or more.

Of the above-mentioned weak acids, cunic acid, sulfamic acid and phosphoric acid are more preferred, and cunic acid and sulfamic acid are more preferred. Since these citric acid and sulfamic acid are powders, the form of the silver detergent according to the present invention can be made into a powder having excellent handling properties during storage or transportation. In other words, a powdery silver detergent can be produced. In addition, sulfamic acid is inexpensive, and since the amide group present in the molecule has a reducing property, it is a complex-forming compound due to atmospheric oxygen. It also has the function of inhibiting the oxidation of urea (for example, urea) (the function as a so-called antioxidant). Therefore, among the weak acids exemplified above, sulfamic acid is most preferred.

 A relatively strong acid having a pKa of about 0.5 to 2, such as sulfamic acid, has excellent washing ability, but is a complex-forming compound (eg, thiourea) due to the acid. Accelerates the decomposition of silver, which reduces the shelf life of the silver detergent. However, when the acid is buffered by mixing the acid with a base, or more preferably, a salt of a weak acid, the decomposition of the complex-forming compound is suppressed while maintaining the washing ability. it can.

 Therefore, silver cleaners, especially silver cleaners containing a weak acid with a pKa in the range of 0.5 to 2, preferably further comprise a base and a di- or weak acid salt in addition to the weak acid. .

Therefore, for example, when sulfamic acid is used as a weak acid, a compound such as ammonia, ammonium carbonate, ammonium hydrogencarbonate, or ammonium sulfamic acid should be added to the sulfamic acid. More preferably, a buffer solution is formed by adding at least one compound selected from the group consisting of powders of ammonium carbonate, ammonium hydrogencarbonate and ammonium sulfamate, which are powders. Alternatively, it is more desirable to partially neutralize the sulfamic acid. This increases the pH, so that the decomposition of the complex-forming compound can be further suppressed while maintaining the cleaning ability, and the storage stability of the silver detergent can be further improved. Sulfamic acid has a lower environmental load (eg, eutrophication) at the time of disposal than, for example, phosphoric acid. In addition, ammonium bisulfate obtained by decomposing sulfamic acid is buffered with sulfamic acid. Since it has the property, the decomposition of the complex-forming compound can be suppressed. Further, since the sulfamic acid complex salt has a high solubility, even when a relatively large amount of silver products are washed using the silver detergent according to the present invention, there is no possibility of causing precipitation or the like. .

 The content of the weak acid in the silver detergent, that is, the concentration in the washing solution such as an aqueous solution, may be set according to the kind of the weak acid, the combination with the complex-forming compound, and the like, and is not particularly limited. However, in the case of a weak acid in a liquid state, the weight is more preferably in the range of 1% to 99% by weight, more preferably in the range of 5% to 50% by weight, and more preferably 10% by weight. % To 30% by weight is particularly preferred. In the case of a solid weak acid, the range of 1% to 30% by weight is more preferable, the range of 5% to 20% by weight is more preferable, and the range of 8% to 1% by weight. A range of 5% by weight is particularly preferred. In a silver detergent, that is, a washing solution, the concentration of a weak acid is reduced when the weak acid reacts with a complex-forming compound, a metal, or the like during use. Therefore, if the concentration of the weak acid is lower than the above range, the washing ability of the silver detergent may not be sufficiently exhibited, and the washing ability may be further reduced as the concentration decreases. On the other hand, if the concentration of the weak acid is higher than the above range, in the case of a liquid weak acid, the concentration of the complex-forming compound becomes relatively low, so that the cleaning ability of the silver detergent may not be sufficiently exhibited. . In the case of a solid weak acid, the weak acid may precipitate out in a saturated state, and the washing ability of the silver detergent may become poor. When two or more weak acids are used in combination, the mixing ratio of these weak acids is not particularly limited.

The deodorant as an additive optionally contained in the silver detergent according to the present invention removes a slight odor derived from, for example, a complex-forming compound generated during washing. Any compound having the ability to smell may be used. As the deodorant, a water-soluble amphoteric surfactant is preferable, and examples thereof include imidos such as carboxybetaine, sulfobenzoin, amino carboxylate, and imidazolium betaine. Examples include, but are not limited to, dazoline derivatives and alkylethylene triaminoacetic acid. In addition, various adsorbents and compounds that react with hydrogen sulfide to form odorless compounds can also be used as deodorants. One of these deodorants may be used alone, or two or more of them may be used in combination. When the form of the silver detergent is paste or solid, a solid adsorbent can be used as the deodorant. Various oxidizing agents generally used as deodorants are not suitable as the deodorant according to the present invention.

 The protective agent as an additive that is optionally contained in the silver detergent according to the present invention is a compound having an ability to prevent a sulfide film from being formed again on the surface of the silver product after washing. Any compound may be used, but a compound having water solubility or a compound soluble in acid is desirable. Examples of the antibacterial agent include sulfonic acids, sulfonates, aldehydes, acetylenic alcohols, amines, quaternary ammonium salts such as tetraptylammonium chloride, and the like. Examples thereof include a heterocyclic compound and a phosphonium compound, but are not particularly limited. Furthermore, the amphoteric surfactants exemplified as the deodorant also have an anti-reflection function. Therefore, the amphoteric surfactant can also be used as a protective agent. One of these protective agents may be used alone, or two or more thereof may be used in combination. Note that various types of protective agents containing sulfur as sulfide are not suitable as the protective agents according to the present invention.

Oil as an additive optionally contained in the silver detergent according to the present invention The cleaning agent is not particularly limited as long as it is a compound having a capability of cleaning oil (for example, stains such as hand marks) attached to the surface of the silver product. Further, the amphoteric surfactants exemplified as the deodorant also have an oil-cleaning ability. Therefore, the amphoteric surfactant can also be used as an oil detergent. One type of oil detergent may be used alone, or two or more types may be used in combination.

 Further, since it has the functions of the above-mentioned deodorant, promotional agent and oil-cleaning agent, the above-mentioned amphoteric surfactant is most suitable as the additive according to the present invention.

 The content of the additive in the silver detergent, that is, the concentration in the washing solution such as an aqueous solution is not particularly limited, but is preferably in the range of 0.01% to 20% by weight. More preferably, it is in the range of 0.1% by weight to 5% by weight. If the concentration of the additive is higher than 20% by weight, the concentration of the complex-forming compound and the concentration of the weak acid become relatively low, so that the cleaning ability of the silver detergent may not be sufficiently exhibited. Also, when the additive is a surfactant, the viscosity of the cleaning solution increases, and bubbles may remain when drained after cleaning.

 The silver detergent according to the present invention has a condition that the detergency (hereinafter simply referred to as detergency) after immersion for 45 seconds of silver blackened with sodium polysulfide is 80 or more. To be satisfied. The detergency is a value indicating the ability of the silver detergent to wash in a short time. The measuring method of the detergency is shown below. The above immersion time (45 seconds) is the time determined by experiments so that the difference in cleaning ability is most noticeable.

That is, first, 100 g of sulfur was added to 100 g of sodium sulfide 'nonahydrate. The mixture is heated and melted to form sodium polysulfide, and then suspended in 1 L of water to prepare a sodium polysulfide suspension. Next, a silver plate having a size of 160 mm xl 600 mm x 0.1 mm was immersed in the suspension at room temperature (25 ° C), and the surface of the silver plate was sulfided. Form a coating. Then, after 10 to 20 seconds have passed since the immersion, the silver plate is taken out and washed with water when the whole is uniformly and completely blackened. Next, the silver plate is cut into a size of 20 mm × 20 mm × 0.1 mm to prepare a plurality of test pieces.

The test piece is immersed in 7 ml of the silver detergent to be measured at room temperature (25 te), and the silver detergent is stirred. Next, the test specimen is taken out 45 seconds after the immersion. The lightness of the surface of the test piece after cleaning is measured using a colorimeter (model used: CHNO MA METERCR-200, manufactured by Minoru Yuu Co., Ltd.), and this value is used as the cleaning power. You. When the surface of the test piece is completely cleaned, the lightness, that is, the cleaning power, is about 94 (because there is some light absorption). In other words, it can be quantitatively determined that the greater the brightness, the greater the detergency. When the cleaning power is less than 80, the surface of the test specimen after cleaning is still felt dirty because the sulfide film is not sufficiently dissolved and removed. Since the silver detergent according to the present invention has a detergency of 80 or more as measured by the above method, the silver detergent has an excellent detergency as compared with conventional silver detergents. The sulfide film on the surface of the silver product can be dissolved / removed only by immersing it in a cleaning agent or performing a simple treatment such as light rubbing after immersion. That is, the silver detergent according to the present invention is obtained by immersing a silver product in the silver detergent or by performing a simple treatment such as rubbing lightly after immersion. By simply rinsing, the sulfide film on the surface of the silver product can be dissolved and removed. The conditions for using the silver detergent are not particularly limited. When used, the silver detergent is diluted with a solvent such as water within a range that does not impair the cleaning ability, and more specifically, so that the concentrations of the complex-forming compound and the weak acid do not fall below the above range. Is also good. That is, the silver detergent can be used after being diluted as necessary.

 Further, the silver detergent according to the present invention is safe and odorless, and is chemically stable, so that it can be stored for a long period (several months or more). Then, by washing the silver product using the silver detergent according to the present invention, it is possible to restore the beautiful shine unique to silver without damaging the surface. In other words, the sulfide film on the surface of silver products can be dissolved and removed by a simple treatment, and it is safe, odorless, chemically stable, and can be stored for a long time. Silver detergent can be provided.

 In the above description, for convenience, the case where the form of the silver detergent is liquid is described as an example.For example, when the form of the silver detergent is paste or solid, the form of the silver detergent is used. If necessary, the powder further contains various powders. Specifically, for example, when the complex-forming compound is a water-soluble organic compound, Silica or a powder containing the silica as a main component, such as silica, diatomaceous earth, or fine sea sand, is preferred.

If the form of the silver detergent is paste-solid, the silver detergent is attached to the silver product, or after the attachment, simple treatment such as rubbing lightly or wiping lightly is used. Simply by applying, it is possible to dissolve and remove the sulfide film on the surface of the silver product. Also, if the form of silver detergent is aerosol, In this case, a silver detergent is sprayed on the silver product, or after spraying, the sulphated film on the surface of the silver product is dissolved and removed simply by gently rubbing or gently wiping. can do. In addition, if the silver detergent is in the form of impregnating a base material such as paper or cloth, simply apply a simple treatment such as rubbing or gently wiping the silver product with the silver detergent. Thus, the sulfide film on the surface of the silver product can be dissolved and removed.

 The metal detergent for cleaning a metal product containing a metal other than silver according to the present invention (hereinafter, referred to as a metal detergent) comprises: a complex-forming compound capable of forming a complex salt containing a metal other than silver; The composition contains a weak acid. The metal detergent can take various forms such as liquid-like, paste-like, powder-like, solid-like, and aerosol. Alternatively, the metal detergent according to the present invention may be in a form in which a base material such as paper or cloth is impregnated. Therefore, when the above-mentioned metal detergent is in a liquid form, it further contains a solvent such as water or a lower alcohol. In the following description, for convenience, the case where the form of the metal detergent is liquid is described as an example.

Metal products to be cleaned with metal cleaning agents include metals other than silver with a standard redox potential equal to or greater than hydrogen, more specifically, for example, copper, brass (brass), nickel, tin. It may contain at least one kind of metal selected from the group consisting of gold, platinum group, lead, bismuth, and antimony, or may be made of an alloy containing these metals. Alternatively, the metal product may be a product in which the metal or the alloy is used in a part of a decoration such as a pattern, or a product in which a metal plate such as a gold metal plate is applied _(in short, The metal product to be cleaned by the metal cleaning agent according to the present invention is a metal product containing a metal other than silver (hereinafter simply referred to as a metal product). I just need. Specific examples of the metal products include various kinds of metal tableware (Western tableware) such as dishes, pots, spoons, knives and forks, and jewelry such as accessories and cups. The force is not particularly limited. Note that the term “to be washed” refers to, for example, metal oxides and hydroxides containing metals other than silver, basic metal carbonates, basic metal sulfates, and the like.

 The complex-forming compound contained in the metal detergent according to the present invention has a water solubility by reacting with a metal oxide containing a metal other than silver formed on the surface of the metal product, that is, a metal other than silver. It is a compound which forms a stable complex salt containing, preferably not a poisonous or deleterious substance, and which does not generate an irritating odor when used, and is not particularly limited, but is water-soluble. Organic compounds are preferred. The water-soluble organic compound is not easily decomposed by a weak acid such as sulfamic acid and phosphoric acid. In addition, the water-soluble organic compound hardly reacts with metals other than silver on the surface (that is, metals other than silver that have not been corroded) (the reaction rate is extremely small as compared with 錡). In other words, the complex-forming compound can selectively dissolve and remove only the surface of the metal product. In the present invention, an acid-soluble compound that is sparingly soluble in water is included in the water-soluble organic compound.

 Specific examples of the water-soluble organic compound include, for example, the various compounds described above as examples of the water-soluble organic compound suitable as a complex forming compound in a silver detergent. One of these water-soluble organic compounds may be used alone, or two or more thereof may be used in combination. Among the compounds exemplified above, thioglycolic acid and its esters, and thiourea and its derivatives are more preferable, and thiourea is particularly preferable because it is inexpensive.

Content of complex forming compounds in metal detergents, i.e. washing of aqueous solutions, etc. The concentration in the solution may be set according to the type of the complex-forming compound, the combination with a weak acid, and the like, and is not particularly limited. A higher concentration is preferable because the reaction rate becomes higher. In the range of 1% to 30% by weight, more preferably in the range of 5% to 20% by weight, and in the range of 8% to 12% by weight. Is particularly preferred. In a metal detergent, that is, a washing solution, the concentration of the complex-forming compound as an active ingredient is adjusted by forming a complex salt containing a metal other than silver at the time of use, that is, the complex-forming compound is a compound other than silver. It decreases by reacting with metal (II), and also by hydrolysis by weak acid and air oxidation. Therefore, if the concentration of the complex-forming compound is less than 1% by weight, the cleaning ability of the metal detergent may not be sufficiently exhibited, and the cleaning ability may be further reduced as the concentration decreases. . On the other hand, when the concentration of the complex-forming compound exceeds 30% by weight, the viscosity of the washing solution increases, and the complex-forming compound may precipitate and become not involved in the reaction with the metal (錡) other than silver. It is uneconomical. In addition, since the concentration of suspended solids in the cleaning solution may increase, the metal product surface may not be sufficiently cleaned. When two or more complex forming compounds are used in combination, the mixing ratio of these complex forming compounds is not particularly limited.

The weak acid contained in the metal detergent according to the present invention generates hydrogen ions, but does not easily decompose the complex-forming compound, and is preferably not a toxic substance or a deleterious substance, and does not generate a pungent odor during use. Any acid may be used as long as it is stable in nature, but a higher hydrogen ion concentration is preferable because the reaction rate becomes higher, and in view of the detergency, the pKa force is preferably 4 or less. Desirable. In the present invention, a weak acid is an acid other than a strong acid such as sulfuric acid, hydrochloric acid, or nitric acid. Therefore, an acid having a buffering capacity (buffering action) in a certain region is indicated.

 Examples of the weak acid include, for example, citric acid, sulfamic acid, formic acid, acetic acid, propionic acid, tartaric acid, phosphoric acid, hypophosphorous acid, phosphorous acid, Examples thereof include, but are not limited to, phosphoric acid, metallic acid, and pyrrolic acid. These weak acids may be used alone or in combination of two or more.

 Of the above-mentioned weak acids, cunic acid, sulfamic acid, and phosphoric acid are more preferable, and cunic acid and sulfamic acid are more preferable. Since these citric acid and sulfamic acid are powders, the form of the metal detergent according to the present invention can be made into a powder having excellent handling properties during storage or transportation. That is, a powdery metal detergent can be manufactured. In addition, sulfamic acid is inexpensive, and since the amide group present in the molecule has a reducing property, a complexing compound due to atmospheric oxygen (eg, thiourea) It also has the function of suppressing the oxidation of soybeans (the function as a so-called antioxidant). Therefore, among the weak acids exemplified in h, sulfamic acid is most preferred.

 A relatively strong acid having a pKa of about 0.5 to 2, such as sulfamic acid, has excellent washing ability, but is a complex-forming compound (eg, thiourea) due to the acid. If the acid is mixed with a base or, more preferably, a salt of a weak acid to form a buffered state (buffer solution), the washing ability will be reduced. The decomposition of the complex-forming compound can be suppressed while maintaining the above.

Therefore, metal detergents, especially weak acids with a pKa in the range of 0.5 to 2 It is preferred that the metal detergent containing further contains a base and / or a weak acid salt in addition to the weak acid.

 Therefore, for example, when sulfamic acid is used as a weak acid, it is necessary to add a compound such as ammonium carbonate, ammonium hydrogencarbonate, ammonium sulfinate to the sulfamic acid. More preferably, the addition of at least one compound selected from the group consisting of powdered ammonium carbonate, ammonium bicarbonate and ammonium sulfamate is more preferred. It is more desirable to form a buffer or to partially neutralize sulfamic acid. This increases the pH, so that the decomposition of the complex-forming compound can be further suppressed while maintaining the cleaning ability, and the preservability of the metal detergent can be further improved. Sulfamic acid has a lower environmental load (eg, eutrophication) at the time of disposal than, for example, phosphoric acid. Further, ammonium hydrogen sulfate obtained by decomposing sulfamic acid has a buffering property with respect to sulfamic acid, so that the decomposition of the complex-forming compound can be suppressed. Furthermore, since the sulfamic acid complex salt has a high solubility, even when a relatively large amount of metal products are washed using the metal detergent according to the present invention, there is no possibility that precipitation or the like will occur.

The content of the weak acid in the metal detergent, that is, the concentration in the washing solution such as an aqueous solution may be set according to the kind of the weak acid, the combination with the complex-forming compound, and the like, and is particularly limited. However, in the case of a weak acid in a liquid state, the range of 1% to 99% by weight is more preferable, and the range of 5% to 50% by weight is more preferable. Particularly preferred is a range of 0% by weight to 30% by weight. In the case of a solid weak acid, the range of 1% to 30% by weight is better. It is more preferably in the range of 5% by weight to 20% by weight, and particularly preferably in the range of 8% by weight to 15% by weight. In a metal cleaning agent, that is, a cleaning solution, the concentration of a weak acid is reduced by the reaction of the weak acid with a complex-forming compound or a metal other than silver (i 靑) during use. Therefore, if the concentration of the weak acid is lower than the above range, the cleaning ability of the metal detergent may not be sufficiently exhibited, and the washing ability may be further reduced as the concentration decreases. If the concentration is higher than the above range, in the case of a weak acid in a liquid state, the concentration of the complex-forming compound becomes relatively low, so that the cleaning ability of the metal detergent may not be sufficiently exhibited. In the case of a solid weak acid, the weak acid may precipitate in a saturated state, and the cleaning ability of the metal detergent may become poor.c When two or more weak acids are used in combination, The mixing ratio of the weak acid is not particularly limited.

 The metal detergent according to the present invention preferably further contains at least one additive selected from the group consisting of a deodorant, a deodorant, and an oil detergent. The above-mentioned deodorant is completely the same as that contained in the silver detergent as needed.

The anti-oxidant as an additive optionally contained in the metal cleaning agent according to the present invention has an ability to prevent the formation of oxide film and the like on the surface of the metal product after cleaning. Any compound may be used as long as it is a water-soluble compound or a compound soluble in an acid. As the deodorant, various compounds exemplified as the promotional agent and the amphoteric surfactant exemplified as the deodorant which can be used as needed in the silver detergent can be used. One of these protective agents may be used alone, or two or more thereof may be used in combination. The urea urea exemplified as a complex-forming compound also has an anti-reflection function. ing.

 The oil detergent as an additive optionally contained in the metal detergent according to the present invention is a compound having an ability to wash oil (for example, stains such as hand marks) attached to the surface of a metal product. There is no particular limitation. Further, the amphoteric surfactants exemplified as the deodorant also have an oil-cleaning ability. Therefore, the amphoteric surfactant can also be used as an oil detergent. Only one type of oil detergent may be used, or two or more types may be used in combination.

 And since it has both the functions as the above-mentioned deodorant, anti-oxidant and oil-cleaning agent, the above-mentioned amphoteric surfactant is the most suitable as the additive according to the present invention. When the metal product is a copper product containing copper or brass, among the amphoteric surfactants, imidazoline derivatives are particularly preferred.

 The content of the additive in the metal detergent, that is, the concentration in the cleaning solution such as an aqueous solution is not particularly limited, but is preferably in the range of 0.01% by weight to 20% by weight. More preferably, it is in the range of 0.1% by weight to 5% by weight. If the concentration of the additive is higher than 20% by weight, the concentration of the complex-forming compound and the concentration of the weak acid become relatively thin, and the cleaning ability of the metal detergent may not be sufficiently exhibited. Also, when the additive is a surfactant, the viscosity of the cleaning solution increases, and bubbles may remain when drained after cleaning.

The metal detergent according to the present invention has the following conditions: (1) a condition that the detergency (hereinafter, referred to as copper detergency) of copper aged by using a 1% by weight aqueous acetic acid solution after immersion for 5 minutes is 65 or more; ② 5 minutes of brass grown with 1% by weight acetic acid aqueous solution Detergency after immersion for a while (hereinafter referred to as brass detergency) is 75 or more; and ③ Detergency after immersion for 5 minutes in Nigel rubbed with 1% by weight hydrochloric acid aqueous solution ( (Hereinafter referred to as nickel cleaning power) is 70 or more. These copper cleaning power, brass cleaning power and nickel cleaning power are values indicating the cleaning power of the metal cleaning agent. The methods for measuring the copper cleaning power, brass cleaning power and nickel cleaning power are shown below. The above immersion time (5 minutes) is the time determined by experiments so that the difference in cleaning ability is most noticeable.

 The measuring method of copper cleaning power is as follows. That is, a copper plate having a size of 160 mm × 160 mm × 0.1 mm is immersed in a 1% by weight aqueous acetic acid solution at room temperature (25 ° C.) for 1 minute, and then the copper plate is taken out. Then, without washing with water, the copper plate is placed on a filter paper, dried in the air, and left for one week, thereby forming a green or brown color on the entire surface of the copper plate. After that, the copper plate is cut into a size of 20 mm 20 mm x 0.1 mm to prepare a plurality of test pieces.

After immersing the test piece in 7 ml of the metal detergent to be measured at room temperature (25 ° C) for 5 minutes, remove the test piece and wash it with water. The lightness of the surface of the test piece after cleaning was measured using a colorimeter (model used: CHROMA METERCR-200, manufactured by Minolta Co., Ltd.), and this value was used as the copper cleaning power. . When the surface of the test piece is completely cleaned, the lightness. That is, the copper cleaning power is about 75 (due to light absorption). In other words, it can be quantitatively determined that the greater the brightness, the greater the copper cleaning power. If the copper cleaning power is less than 65, 錡 is not sufficiently dissolved and removed, so it seems that the surface of the test specimen after cleaning is still dirty. It is.

 The measuring method of the brass detergency is as follows. That is, a brass plate having a size of 160 mm × 1ϋ0 mm × 0.1 mm was immersed in a 1% by weight acetic acid aqueous solution at room temperature (25 ° C.) for 1 minute, and then the brass plate was removed. Take out. Then, without washing with water, the brass plate is placed on a filter paper, dried in the air, and left for one week. Thereby, a light brown 锖 is formed on the entire surface of the brass plate. Thereafter, the brass plate is cut into a size of 20 mm 20 mm x 0.1 mm to prepare a plurality of test pieces.

The above test piece is immersed in 7 m 1 of a metal detergent to be measured at room temperature (25 ° C) for 5 minutes, then the test piece is taken out and washed with water. Then, the lightness of the surface of the test piece after cleaning is measured using the above colorimeter, and this value is used as the brass cleaning power. When the surface of the test piece is completely cleaned, the lightness, ie, the brass cleaning power, is about 85 (because of light absorption). That is - as brightness is large, Note _c can be quantitatively determined with brass detergency is large, when the brass detergency is less than 7 5 because錡is not sufficiently dissolved and removed, The surface of the test piece after cleaning still seems to be dirty.

The measuring method of nickel cleaning power is as follows. That is, a nickel plate having a size of 160 mm × 60 mm × 0.1 mm is immersed in a 1% by weight aqueous hydrochloric acid solution at room temperature (25 ° C.) for 1 minute, and then the nickel plate is taken out. Then, without washing with water, the Nigger plate is placed on a filter paper, dried in the air, and left for one week. Thereby, a green triangle is formed on the entire surface of the nickel plate. Thereafter, the nickel plate is cut into a size of 20 mm 20 mm x 0.1 mm to prepare a plurality of test pieces. After immersing the test piece in 7 ml of the metal detergent to be measured at room temperature (25 ° C) for 5 minutes, remove the test piece and wash it with water. Then, the lightness of the test specimen surface after washing is measured using the above colorimeter, and this value is used as the nickel washing power. When the surface of the test piece is completely cleaned, the lightness, that is, the nickel cleaning power is about 86 (because there is light absorption)

). In other words, it can be quantitatively determined that the greater the brightness, the greater the nickel cleaning power. When the nickel cleaning power is less than 70, 錡 is not sufficiently dissolved and removed, so that the surface of the test piece after cleaning still seems to be dirty.

 The metal cleaning agent according to the present invention has a copper cleaning power of at least 65, a brass cleaning power of at least 75, and a nickel cleaning power of at least 70, as measured by the above method. It has at least one of the following conditions: it has better cleaning performance compared to conventional metal cleaners, and therefore can be immersed in metal cleaners, or After the rinsing, a simple treatment such as light rubbing can be applied to dissolve and remove the surface of the metal product, dirt, and the like. That is, the metal detergent according to the present invention can be obtained by immersing a metal product in a metal detergent, or by performing a simple treatment such as light rubbing after immersion, to obtain a stain on the surface of the metal product. Etc. can be dissolved and removed. The conditions for using the metal detergent are not particularly limited. The metal detergent is diluted with a solvent such as water when used within a range that does not impair the cleaning ability, and more specifically, so that the concentrations of the complex-forming compound and the weak acid do not fall below the above range. Is also good. That is, the metal detergent can be used after being diluted as necessary.

Further, the metal detergent according to the present invention is safe, odorless, and Since it is chemically stable, it can be stored for a long time (several months or more). Then, by cleaning the metal product using the metal cleaning agent according to the present invention, a beautiful shine unique to the metal can be restored without damaging the surface. In other words, it is possible to dissolve and remove stains and the like on the surface of metal products by simple treatment, and it is safe and odorless, and is chemically stable, A metal detergent that can be stored can be provided.

 In the above description, for the sake of convenience, the case where the form of the metal detergent is liquid has been described as an example. However, for example, when the form of the metal detergent is paste or solid, The agent further contains various powders as necessary. As the powder, specifically, for example, when the complex-forming compound is a water-soluble organic compound, the powder mainly uses a silica force or a silica force of white clay, diatomaceous earth, fine sea sand, or the like. Powder as a component is preferred.

When the form of the metal detergent is paste or solid, the metal detergent is attached to the metal product, or after the attachment, a simple rubbing or wiping is performed. By simply performing the treatment, it is possible to dissolve and remove dirt and the like on the surface of the metal product. When the metal cleaning agent is in the form of an air sol, the metal product is sprayed with a metal cleaning agent or, after spraying, subjected to a simple treatment such as rubbing lightly or wiping lightly. It can dissolve and remove stains and the like on the surface of metal products. In addition, when the metal detergent is in a form in which a base material such as paper or cloth is impregnated, simply apply a simple treatment such as rubbing or wiping the metal product gently with the metal detergent. It can dissolve and remove dirt and the like on the surface of the metal product. Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples (conventional examples). However, the present invention is not limited by these. (Example 1)

 Aqueous solution containing 9% by weight of thiourea (complex forming compound), 5% by weight of citric acid (weak acid) and 7.6% by weight of phosphoric acid (weak acid), that is, the silver detergent according to the present invention. Was prepared. The pH of the silver detergent was 0.86, and the oxidation-reduction potential (ORP, hereinafter simply referred to as oxidation-reduction potential) using a silver-silver chloride-monochloride rim-saturated electrode as a reference electrode was determined. It was 27 mv. The silver detergent slightly smelled sulfur, but no precipitation was observed.

 Then, the detergency was measured using the above silver detergent. However, the brightness of the polished silver plate was 97.90, and the brightness of the silver plate before dipping in the sodium polysulfide suspension (forming a sulfide film) was 94.36. Was. The lightness of the silver plate (test piece) after immersion was 55.558. As a result, the lightness of the test specimen surface (both sides) after cleaning, that is, the detergency was 84.70 and 88.20 (average value 86.5).

 The test piece prepared by the above method was immersed in the silver detergent 洗浄 m 1 prepared by the above method, and the silver detergent was stirred. Then, the time required for the brightness of the entire test piece to become almost equal to the brightness of the silver plate before the formation of the sulfide coating (hereinafter referred to as the reference brightness) was measured (up to 5 minutes). This value was used as the limit detergency. As a result, the limiting detergency was about 2 minutes. Also, the time required for 90% or more of the brightness of the test piece surface to be substantially equal to the reference brightness, that is, the 90% limit detergency was about 1 minute. In addition, it was visually determined whether or not the two brightnesses were substantially equal. At the time of cleaning, a slight smell of hydrogen sulfide was emitted.

(Conventional example 1) The detergency was measured using a commercially available detergent (A) instead of the silver detergent according to the present invention. The pH of the commercial detergent (A) was 0.73, and the oxidation-reduction potential was 94 mV. Further, the commercial detergent (A) was a pink liquid having a strong acid odor, and a large amount of precipitates like sulfur was recognized.

 As a result, the cleaning power of the test specimen surface after cleaning was 65.58 and 82.4

2 (average value 74.0). Further, the limit detergency was about 3 minutes, and the 90% limit detergency was about 1 minute. During cleaning, a strong hydrogen sulfide odor was emitted.

 (Conventional example 2)

 The detergency was measured using a commercially available detergent (B) instead of the silver detergent according to the present invention. The pH of the commercially available detergent (B) was 0.25, and the oxidation-reduction potential was 73 mV. Further, the commercial detergent (B) was a pale yellow liquid having no irritating odor, and a large amount of precipitates like sulfur was observed.

 As a result, the cleaning power of the test piece surface after cleaning was 59.51 and 87.90 (average value of 73.7). The limit detergency was about 2.5 minutes, and the 90% limit detergency was about 1 minute. At the time of cleaning, hydrogen sulfide smell was emitted.

 (Conventional example 3)

 The detergency was measured using a commercially available detergent (C) instead of the silver detergent according to the present invention. The pH of the commercially available detergent (C) was 0.86, and the oxidation-reduction potential was 119 mV. Further, the commercial detergent (C) was a blue liquid having a strong acid odor, and a large amount of precipitate, which was likely to be sulfur, was observed.

As a result, the cleaning power of the test piece surface after cleaning was 64.98 and 58.17 (average value 61.6). The commercial silver detergent (C) Cleaning was incomplete, and the limiting detergency and 90% detergency could not be measured. At the time of cleaning, a strong hydrogen sulfide odor was emitted.

 (Conventional example 4)

 A commercially available detergent (D) was used in place of the silver detergent according to the present invention. The pH of the commercially available detergent (D) was 0.8, and the oxidation-reduction potential was 46 mV. Further, the commercial detergent (D) contained thiourea and sulfuric acid, had a strong acid smell, and a precipitate like sulfur was recognized.

 As a result, the cleaning power of the test piece surface after cleaning was 67.37 and 78.88 (average value 73.1). Further, the limit detergency was about 5 minutes, and the 90% limit detergency was about 3 minutes. At the time of washing, there was a weak odor.

 (Example 2)

 To 100 ml of the aqueous solution prepared in Example 1 was added N-carboxymethyl-N, N-dimethyl-1-N-methyltadecyl ammonium betaine lg as an amphoteric surfactant (deodorant). It was further dissolved. Then, the test piece prepared by the above method was immersed in this aqueous solution, that is, the silver detergent according to the present invention, for 5 minutes.

As a result, the test piece was washed to the same degree as the test piece of Example 1 ₍ at the time of washing, no smell of hydrogen sulfide was felt.

 (Example 3)

100 g of the aqueous solution prepared in Example 1 was further dissolved with 1 g of tetratrapylammonium chloride as a quaternary ammonium salt (an antioxidant). That is, the test piece prepared by the above method was immersed in the silver detergent according to the present invention for 5 minutes. As a result, the test piece was washed to the same degree as the test piece of Example 1, and the average value of the lightness of the test piece surface (both sides) was 92.5. Next, the test piece was washed with running deionized water for 1 minute, placed on a filter paper and left in the air for one month. The average value of the lightness of the test specimen surface (both sides) after standing was 89.3.

 On the other hand, to examine the effect of adding tetrabutylammonium chloride, the test piece was immersed in the aqueous solution prepared in Example 1 for 5 minutes, and then the same operation as above was performed. Was. As a result, the average value of the lightness of the test piece surface (both sides) was 93.7, and the average value of the lightness of the test piece surface (both sides) after being left for one power month was 73.7. Therefore, it was confirmed that the surface of the test piece was protected by tetrabutylammonium chloride, that is, the cleaning solution containing tetrabutylammonium chloride had a protection function. .

 (Example 4)

 100 ml of the aqueous solution prepared in Example 1, that is, an old hundred yen (Inaho) coin blackened to the same degree as the test piece prepared by the above method was added to the silver detergent according to the present invention for 5 minutes. And immersed (rested). The coin had brown deposits.

 As a result, the average value of the lightness of the coin surface (both sides) was 67.2 because the coin had irregularities due to the engraving on its surface, but it was practically (apparent) as in Example 1. It was cleaned to the same extent as the test piece, and the surface gloss was significantly improved.

 (Example 5)

100 ml of the aqueous solution prepared in Example 1 was added to tetrabutylammonium chloride. 1 g of the aluminum was further dissolved. Then, in this aqueous solution, that is, the silver detergent according to the present invention, an old 100 yen (rice ear) coin, which was blackened to the same degree as the test piece prepared by the above method, was immersed (rested) for 5 minutes. . The coin had brown deposits.

 As a result, the coin was washed to the same degree as the test piece of Example 1, and the average value of the lightness of the coin surface (both sides) was 86.7. Further, the deposits were separated from the coin, and could be easily removed by rinsing the coin surface with filter paper after washing with water. Therefore, although the coins had unevenness due to corrosion during blackening, the gloss of the surface was significantly improved.

 (Example 6)

 9% by weight of thiourea, 7.49% by weight (equivalent to 0.77 M) of sulfamic acid (weak acid), 8.8% by weight of ammonium sulfamate (weak acid salt) (0%) An aqueous solution containing cunic acid at a ratio of 5% by weight, that is, a silver detergent according to the present invention was prepared. The pH of the silver detergent was 1.05.

Then, the detergency was measured using the above silver detergent. However, the brightness of the silver plate before dipping in the sodium polysulfide suspension (formation of the sulfurized film) was 94.5. Further, the silver plate (test piece) after immersion surface (both sides) of the lightness 5 5.6 4 and 5 7.6 5 (average 5 6.6 5) a which was _t As a result, after the cleaning the test piece The lightness of the surface (both sides), that is, the detergency was 85.01 and 86.36 (mean value 8.5.69).

Further, the test piece prepared by the above method was immersed in 7 ml of the silver detergent prepared by the above method, and the silver detergent was stirred. The detergency was about 1 to 2 minutes. (Example 7)

 An aqueous solution containing 9% by weight of thiourea (complex-forming compound), 85% by weight of 7.6% by weight of phosphoric acid (weak acid) and 5% by weight of cunic acid (weak acid), that is, the present invention Such a metal detergent was prepared. The pH of the metal detergent was 0.86. No precipitation was observed in the metal detergent.

 Then, the copper cleaning power, the brass cleaning power, and the nickel cleaning power were measured using the above metal cleaning agents. However, the brightness of the copper plate before immersion (formation of water) in the acetic acid aqueous solution was 74.68, and the brightness of the copper plate (test piece) after immersion was 42.35 and 43.62. (Average value 4.29.99). The lightness of the brass plate before immersion in the acetic acid aqueous solution was 85.688, and the lightness of the brass plate after immersion was 51.23 and 50.35 (average value of 50.779). ). The brightness of the nickel plate before immersion in the aqueous hydrochloric acid solution was 86.32, and the brightness of the nickel plate after immersion was 50.03 and 48.63 (average value 49.33). Was.

 As a result, the brightness of the test specimen surface (both sides) after cleaning, that is, the copper cleaning power was 6

9.89 and 68.22 (mean 69.06) and brass detergency 77.23 and 78.01 (mean 77.62), nickel The cleaning power was 72.36 and 76.32 (average 74.34). Further, as judged by visual inspection, each of the test pieces had regained the beautiful shine unique to the metal before the formation of 錡.

At the time of the above measurement, the copper cleaning power, brass cleaning power and nickel cleaning power reached 90% or more of the above measured values one minute after the test piece was immersed in the metal cleaning agent. I was The copper cleaning power, brass cleaning power, and niggel cleaning power are more than 5 minutes after the test piece is immersed in the metal cleaning agent. Nevertheless, it did not exceed the above measured values (even after washing for more than 5 minutes).

 (Example 8)

 9% by weight of thiourea, 7.49% by weight of sulfamic acid (weak acid) (equivalent to 0.77 M), 8.8% by weight of ammonium sulfamate (weak acid salt)

(Equivalent to 0.77 M), an aqueous solution containing 5% by weight of citric acid, that is, a metal detergent according to the present invention was prepared. The pH of the metal detergent was 1.05.

 Then, the copper cleaning power, the brass cleaning power, and the nickel cleaning power were measured using the above metal cleaning agents. As a result, the brightness of the test specimen surface (both sides) after cleaning, that is, the copper cleaning power was 70.22 and 65.32 (average value 67.77), and the brass cleaning power was 8 The values were 0.23 and 76.32 (average value: 78.28), and the Niggel detergency was 75.25 and 76.43 (average value: 7.5.84). Further, as judged by visual inspection, each of the above test pieces had regained the beautiful shine unique to the metal before the formation of 錡.

 At the time of the above measurement, the copper cleaning power, brass cleaning power and nickel cleaning power reached 90% or more of the above measured values one minute after the test piece was immersed in the metal cleaning agent. I was Also, the copper cleaning power, brass cleaning power and Nigel cleaning power are based on the above measured values even if the test piece is immersed in a metal detergent for more than 5 minutes (even if it is washed for more than 5 minutes). Never grew bigger.

The specific embodiments and examples made in the section of the best mode for carrying out the invention are intended to clarify the technical contents of the present invention, and Should be interpreted in a narrow sense limited only to Instead, the present invention can be implemented with various modifications within the spirit of the present invention and the scope of the claims described below. Industrial applicability

 As described above, the silver product detergent of the present invention contains a complex-forming compound capable of forming a complex salt containing silver, and a weak acid, and is prepared by blackening silver that has been blackened using sodium polysulfide. The cleaning power after immersion for 45 seconds is 80 or more. Further, as described above, the silver product detergent of the present invention preferably further comprises at least one additive selected from the group consisting of a deodorant, a deodorant, and an oil detergent. It is. Furthermore, as described above, the silver product detergent of the present invention preferably has a configuration containing an amphoteric surfactant as the additive. This makes it possible to dissolve and remove the sulfide film on the surface of silver products with a simple treatment, and it is safe, odorless, chemically stable, and can be stored for a long time. This has the effect of providing a silver product detergent that is as follows.

 As described above, the silver product cleaning method of the present invention is a method for cleaning silver products using the silver product cleaning agent.

 This makes it possible to dissolve and remove the sulfide film on the silver product surface by simply performing a simple treatment with a silver product detergent that is chemically stable and can be stored for a long time. It is possible to provide a safe and odorless method for cleaning silver products.

As described above, the metal product detergent of the present invention has a configuration including a complex-forming compound capable of forming a complex salt containing a metal and a weak acid. Further, as described above, the metal product detergent of the present invention preferably has the complex forming compound of thiourea. The configuration is as follows. Further, the metal product detergent of the present invention has a configuration as described above. Preferably, the weak acid is sulfamic acid.

 This makes it possible to dissolve and remove dirt and the like on the surface of metal products by simple processing, and is safe, odorless, chemically stable, and stored for a long time. It is possible to provide a metal product cleaning agent that can perform cleaning.

 As described above, the method for cleaning a metal product of the present invention is a method for cleaning a metal product containing a metal other than silver using the above-described metal product cleaning agent.

 As a result, it is chemically stable and can be stored for a long period of time. Simple treatment with a metal product cleaner dissolves dirt and the like on the surface of metal products containing metals other than silver. It is possible to provide a safe and odorless method for cleaning metal products.

Claims

The scope of the claims 1. The detergency after immersion for 45 seconds of silver that contains a complex-forming compound capable of forming a silver-containing complex salt and a weak acid and is blackened using sodium polysulfide is 80 or more. Is a silverware detergent.  2. The silver product detergent according to claim 1, wherein the complex-forming compound is thiourea.  3. The silverware detergent according to claim 1, wherein the weak acid is at least one selected from the group consisting of cunic acid, sulfamic acid, and phosphoric acid.  4. The silverware detergent according to claim 1, wherein the weak acid is sulfamic acid. 5. It further contains a base and a salt or a weak acid salt,  2. The silver product detergent according to claim 1, wherein the pKa of the weak acid is in the range of 0.5 to 2.  6. The silver product detergent according to claim 4, further comprising at least one compound selected from the group consisting of ammonium carbonate, ammonium bicarbonate, and ammonium sulfamate.  7. The silverware detergent according to claim 1, further comprising at least one additive selected from the group consisting of a deodorant, a deodorant, and an oil detergent.  8. The silverware detergent according to claim 7, comprising an amphoteric surfactant as the additive.  9. A metal product cleaner for cleaning metal products containing metals other than silver, A metal product detergent comprising: a complex-forming compound capable of forming a complex salt containing a metal other than silver; and a weak acid. 10. The cleaning agent for metal products according to claim 9, wherein the complex-forming compound is thiourea. 1 1. Above weak acid, Kuen acid, sulfa Mi phosphate and Li also least for a selected from ing group from phosphate which is one of claim 9, wherein the metal product wash净剤_c 1 2,. The weak acid 10. The metal product detergent according to claim 9, wherein is a sulfamic acid.  1 3. Further containing base and di or weak acid salt,  10. The cleaning agent for metal products according to claim 9, wherein the pKa of the weak acid is in the range of 0.5 to 2.  14. The cleaning agent for metal products according to claim 12, further comprising at least one compound selected from the group consisting of ammonium carbonate, ammonium hydrogencarbonate, and ammonium sulfamate.  15. The metal product cleaner according to claim 9, further comprising at least one additive selected from the group consisting of a deodorant, a deodorant, and an oil cleaner.  16. The metal product detergent according to claim 9, which comprises an amphoteric surfactant as the additive.  10. The cleaning agent for metal products according to claim 9, wherein the cleaning power after immersion of copper immersed in an aqueous solution of 17.1% by weight of acetic acid for 5 minutes is 65 or more.  10. The cleaning agent for metal products according to claim 9, which has a detergency of 75 or more after immersion of brass immersed in a 18.1% by weight aqueous solution of acetic acid for 5 minutes.  10. The cleaning agent for metal products according to claim 9, wherein the cleaning power after immersing nickel immersed in an aqueous solution of 19.1% by weight of hydrochloric acid for 5 minutes is about 0 or more. 20. A method for cleaning silver products, wherein the silver products are washed using the silver product cleaning agent according to claim 1. - 21. A method for cleaning a metal product using the metal product cleaning agent according to claim 9 for cleaning a metal product containing a metal other than silver.  22. The metal product according to claim 21, wherein the metal product contains at least one metal selected from the group consisting of copper, brass, nickel, tin, gold, platinum group, lead, bismuth, and antimony. Cleaning method.