WO2022224901A1 - Trivalent chromium plating solution and chromium plating method using same - Google Patents

Trivalent chromium plating solution and chromium plating method using same Download PDF

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WO2022224901A1
WO2022224901A1 PCT/JP2022/017812 JP2022017812W WO2022224901A1 WO 2022224901 A1 WO2022224901 A1 WO 2022224901A1 JP 2022017812 W JP2022017812 W JP 2022017812W WO 2022224901 A1 WO2022224901 A1 WO 2022224901A1
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trivalent chromium
plating solution
chromium plating
group
compound
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PCT/JP2022/017812
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French (fr)
Japanese (ja)
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雄斗 森川
まどか 中上
峻 辻野
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株式会社Jcu
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/04—Electroplating: Baths therefor from solutions of chromium
    • C25D3/06—Electroplating: Baths therefor from solutions of chromium from solutions of trivalent chromium
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/04—Electroplating: Baths therefor from solutions of chromium
    • C25D3/10—Electroplating: Baths therefor from solutions of chromium characterised by the organic bath constituents used

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  • the present invention relates to a trivalent chromium plating solution and a chromium plating method using the same.
  • Chrome plating is used as a decorative coating film because it has a silver-white appearance. Hexavalent chromium was used for this chrome plating, but in recent years, this hexavalent chromium has an adverse effect on the environment, so its use has been restricted, and there has been a shift to technology that uses trivalent chromium. ing.
  • Patent Document 1 describes a technique of precipitating metal impurities in a trivalent chromium plating solution with ferrocyanide and removing the metal impurities by filtration or the like
  • Patent Document 2 describes a trivalent chromium plating solution containing metal impurities. is electrolyzed at a lower current density than the cathodic current density during chromium plating
  • Patent Document 3 reports a technique for removing metal impurities through an iminodiacetic acid type ion exchange resin.
  • the above technique requires a process for removing metal impurities from the trivalent chromium plating solution such as filtration and electrolysis, and a process for regenerating the resin used for removing metal impurities. was sought.
  • an object of the present invention is to provide a new technology that is not affected by metal impurities in the trivalent chromium plating solution.
  • the present invention provides a trivalent chromium plating solution containing a trivalent chromium compound, a complexing agent, and a conductive salt,
  • R 1 represents hydrogen, an optionally substituted benzyl group, or an optionally branched alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group or a carboxyalkyl group
  • R 2 represents hydrogen, an optionally branched C 1-5 alkyl group or a carboxyalkyl group
  • R 3 represents hydrogen, an optionally branched C 1-5 alkyl group or a carboxyalkyl group.
  • a trivalent chromium plating solution characterized by containing one or more selected from a compound represented by, an alkali metal salt of the compound and a hydrate of the alkali metal salt.
  • the present invention is a method for plating an object to be plated with trivalent chromium, characterized by electroplating the object to be plated with the trivalent chromium plating solution.
  • the present invention is a chromium-plated product obtained by electroplating an object to be plated with the trivalent chromium plating solution.
  • the present invention provides a trivalent chromium plating solution containing a trivalent chromium compound, a complexing agent and a conductive salt, in which the compound represented by the general formula (I), an alkali metal salt of the compound and the alkali
  • a method for improving resistance to metal impurities mixed in a trivalent chromium plating solution characterized by containing one or more selected from hydrates of metal salts.
  • the trivalent chromium plating solution of the present invention is not affected even if metal impurities are mixed in the solution. Since there is no need for a regeneration treatment process, etc., plating can be continuously performed without stopping the production line.
  • the trivalent chromium-plated product of the present invention does not cause appearance defects that can be caused by metal impurities in the plating solution, and a uniform metallic luster film can be obtained.
  • FIG. 1 is a diagram showing the results of a Hull cell test of Example 1.
  • FIG. 10 is a diagram showing the results of a Hull cell test of Example 2; 3 is a diagram showing the results of a Hull cell test of Comparative Example 1.
  • FIG. 10 is a diagram showing the results of a Hull cell test of Example 2; 3 is a diagram showing the results of a Hull cell test of Comparative Example 1.
  • the trivalent chromium plating solution of the present invention (hereinafter referred to as “the plating solution of the present invention”) comprises a trivalent chromium plating solution containing a trivalent chromium compound, a complexing agent, and a conductive salt, added with the following general formula (I):
  • One or two or more selected from compounds represented by, alkali metal salts of the compounds, and hydrates of the alkali metal salts (hereinafter, these may be simply referred to as “compounds").
  • R 1 is hydrogen, an optionally substituted benzyl group, or an optionally branched alkyl group having 1 to 10 carbon atoms (having 1 to 10 carbon atoms) It represents a hydroxyalkyl group or a carboxyalkyl group (having 1 to 10 carbon atoms), preferably hydrogen, a hydroxyalkyl group having 1 to 5 carbon atoms or a carboxyalkyl group (having 1 to 5 carbon atoms).
  • a substituent of a benzyl group a hydroxy group etc. are mentioned, for example.
  • R 2 represents hydrogen, an optionally branched alkyl group having 1 to 5 carbon atoms or a carboxyalkyl group (having 1 to 5 carbon atoms), preferably hydrogen or an alkyl group having 1 to 5 carbon atoms.
  • R 3 represents hydrogen, an optionally branched C 1-5 alkyl group or a (C 1-5) carboxyalkyl group, preferably hydrogen or a C 1-5 alkyl group.
  • the above compounds may be salts with alkali metals such as sodium and potassium. Among these salts with alkali metals, sodium salts are more preferred.
  • the alkali metal salts of these compounds may be hydrates. In the plating solution of the present invention, one or more selected from these compounds, alkali metal salts of the compounds, and hydrates of the alkali metal salts can be used.
  • the above compounds include iminodiacetic acid, N-(2-hydroxyethyl)iminodiacetic acid, N-(1-carboxylatoethyl)iminodiacetic acid trisodium (or its hydrate), nitrilot Acetic acid, N-(2-carboxyethyl)iminodiacetic acid, N-(o-hydroxybenzyl)iminodiacetic acid, N-benzyliminodiacetic acid and the like.
  • iminodiacetic acid N-(2-hydroxyethyl)iminodiacetic acid, N-(1-carboxylatoethyl)iminodiacetic acid trisodium (or its hydrated product) is preferred, and iminodiacetic acid is more preferred.
  • the content of the above compound in the plating solution of the present invention is not particularly limited, it is, for example, 0.5 to 10 g/L, preferably 1 to 5 g/L.
  • the compound By using the compound as an active ingredient, the compound can be used as an additive for a trivalent chromium plating solution for improving resistance to metal impurities.
  • This additive for a trivalent chromium plating solution can be added to a conventional trivalent chromium plating solution.
  • the resistance to metal impurities mixed in the trivalent chromium plating solution is improved. can be done. Therefore, there is no need for a step of removing metal impurities such as filtration or electrolysis, or a step of regenerating the resin used for removing metal impurities, which is conventionally required.
  • the trivalent chromium compound used in the plating solution of the present invention is not particularly limited. , is chromium chloride. These trivalent chromium compounds may be used singly or in combination of two or more. Although the content of the trivalent chromium compound in the plating solution of the present invention is not particularly limited, it is, for example, 1 to 25 g/L, preferably 1 to 15 g/L as metallic chromium.
  • the complexing agent used in the plating solution of the present invention is not particularly limited. Examples include aliphatic dicarboxylic acids such as triammonium acid or salts thereof, carboxylic acids having two or more hydroxy groups and two or more carboxy groups such as tartaric acid, diammonium tartrate, and sodium tartrate, or salts thereof. These complexing agents may be used singly or in combination of two or more. Although the content of the complexing agent in the plating solution of the present invention is not particularly limited, it is, for example, 0.1 to 50 g/L, preferably 1 to 30 g/L. Although the compound represented by the general formula (I) has a complexing action, it is not used as a complexing agent in the present invention.
  • the conductive salt used in the plating solution of the present invention is not particularly limited, but examples include sulfates such as potassium sulfate, ammonium sulfate and sodium sulfate; chlorides such as potassium chloride, ammonium chloride and sodium chloride; Examples include ammonium, sulfamate such as sodium sulfamate, and the like. These conductive salts are used for each group, for example, for each group such as sulfates and chlorides. Among these conductive salts, sulfates or chlorides are preferred. These conductive salts may be used singly or in combination of two or more. Although the content of the conductive salt in the plating solution of the present invention is not particularly limited, it is, for example, 100 to 500 g/L, preferably 150 to 300 g/L.
  • the plating solution of the present invention preferably further contains a pH buffer.
  • the pH buffer is not particularly limited, but boric acid, sodium borate, potassium borate, phosphoric acid, dipotassium hydrogen phosphate and the like. Among these, boric acid and sodium borate are preferred. These pH buffers may be used singly or in combination of two or more.
  • the content of the pH buffering agent in the plating solution of the present invention is not particularly limited, it is, for example, 25 to 200 g/L, preferably 50 to 100 g/L.
  • the plating solution of the present invention may further contain polymer compounds such as polyethylene glycol, ascorbic acid, sodium ascorbate, hydrogen peroxide, surfactants, chloral hydrate, sodium thiocyanate, and the like.
  • polymer compounds such as polyethylene glycol, ascorbic acid, sodium ascorbate, hydrogen peroxide, surfactants, chloral hydrate, sodium thiocyanate, and the like.
  • the pH of the plating solution of the present invention is not particularly limited as long as it is acidic. For example, 2 to 4.5 is preferable, and 2.5 to 4.0 is more preferable.
  • the complexing agent may be formic acid or citric acid such as formic acid, ammonium formate, potassium formate, citric acid, triammonium citrate, or and salts thereof. Among these, ammonium formate and triammonium citrate are preferred.
  • these complexing agents can be used singly or in combination of two or more.
  • the content of the complexing agent in the plating solution of the present invention is not particularly limited, it is, for example, 0.5 to 60 g/L, preferably 1 to 50 g/L.
  • the conductive salt of the plating solution of the present invention is a chloride
  • the bromide content in the plating solution of the present invention is not particularly limited, but is, for example, 0.5 to 60 g/L, preferably 1 to 20 g/L.
  • chloride When chloride is used as a conductive salt in the plating solution of the present invention, it is preferable to use formic acid or citric acid or a salt thereof as a complexing agent, and it is particularly preferable to use bromide in combination.
  • composition of the plating solution of the present invention when chloride is used as the conductive salt is as follows.
  • the complexing agent may be, for example, a carboxylic acid having two or more hydroxy groups and two or more carboxyl groups, or a salt thereof. is preferred.
  • the complexing agent include carboxylic acids such as tartaric acid, diammonium tartrate, Rochelle salts, and salts of the above carboxylic acids such as sodium tartrate.
  • tartaric acid or diammonium tartrate is preferred, and diammonium tartrate is more preferred.
  • These complexing agents may be used singly or in combination of two or more.
  • the content of the carboxylic acid or its salt in the plating solution of the present invention is not particularly limited, but is, for example, 0.1 to 90 g/L, preferably 1 to 60 g/L.
  • the conductive salt of the plating solution of the present invention is a sulfate
  • the sulfur-containing organic compound used in the plating solution of the present invention is not particularly limited. Sulfur-containing organic compounds having an allyl group such as thiacyanate, [[amino(imino)methyl]thio]acetic acid, 3-[[amino(imino)methyl]thio]propanoic acid, 2-iminothiazolidin-4-one, 2 -Amino-5,6-dihydro-4H-1,3-thiazin-4-one and other carboxylic acids having a carbamimidoylthio group, dehydration products thereof, thiourea, sodium thiocyanate and the like.
  • sulfur-containing organic compounds may be used alone or in combination of two or more.
  • a combination of one or more selected from the group consisting of saccharin or a salt thereof, a sulfur-containing organic compound having an allyl group, a carboxylic acid having a carbamimidoylthio group and/or a dehydration reaction product thereof is preferred, and sodium saccharinate is particularly preferred.
  • the content of the sulfur-containing organic compound in the plating solution of the present invention is not particularly limited, it is, for example, 0.5 to 10 g/L, preferably 2 to 8 g/L.
  • a carboxylic acid having two or more hydroxy groups and two or more carboxy groups or a salt thereof it is preferable to use a carboxylic acid having two or more hydroxy groups and two or more carboxy groups or a salt thereof as a complexing agent.
  • saccharin or a salt thereof it is particularly preferred to use saccharin or a salt thereof in combination.
  • composition of the plating solution of the present invention when sulfate is used as a conductive salt is as follows.
  • the method for preparing the plating solution of the present invention described above is not particularly limited. It can be prepared by adding and mixing a sulfur-containing organic compound, a surfactant, etc., if necessary, and finally adjusting the pH with sulfuric acid, hydrochloric acid, aqueous ammonia, or the like.
  • the plating solution of the present invention can plate an object to be plated with chromium by electroplating the object to be plated with the plating solution of the present invention in the same manner as the conventional chrome plating solution.
  • the plating solution of the present invention does not adversely affect the appearance even if metal impurities are mixed in during plating, and does not require operations to remove metal impurities such as filtration and electrolysis, and can be used continuously without stopping the production line. can be plated.
  • the metal impurities are metals derived from the underlying plating and other chemicals associated with the plating. Specific metals include, for example, nickel, zinc, copper, hexavalent chromium, etc. Nickel and copper, which are often used for base plating, are preferred.
  • the content of metal impurities that does not affect the plating solution of the present invention is not particularly limited, but is, for example, 0 to 200 mg/L, preferably 0 to 100 mg/L.
  • iridium oxide may be electroplated at a cathode current density of 2-20 A/dm 2 for 1-15 minutes.
  • Examples of objects that can be electroplated include metals such as iron, stainless steel, and brass, and resins such as ABS and PC/ABS.
  • the object to be plated may be plated with copper, nickel or the like before being treated with the plating solution of the present invention.
  • the layers may be provided in order of semi-bright nickel plating, bright nickel plating, and microporous nickel plating.
  • the potential difference between each layer is not particularly limited. 100 mV is preferred.
  • the layers may be provided in order of semi-bright nickel plating, high sulfur content nickel plating, bright nickel plating, and microporous nickel plating.
  • the potential difference of each layer is not particularly limited. 50 to -5 mV, and the potential difference of the microporous nickel plating to the bright nickel plating is preferably in the range of 20 to 100 mV.
  • the chromium-plated product thus obtained has a highly decorative metallic luster and a coating with excellent corrosion resistance.
  • this chrome plating may be subjected to chromate treatment. This improves corrosion resistance.
  • the conditions for the chromate treatment are not particularly limited. good.
  • Examples 1-10 and Comparative Examples 1-7 Chrome-plated: A trivalent chromium plating solution was prepared by dissolving each of the compounds listed in Table 1 in water (Examples 1 to 8 and Comparative Examples 1 to 6 were chloride baths, Examples 9 to 10 and Comparative Example 7 were sulfuric acid Salt bath, Examples 2-8, Example 10, Comparative Examples 1-4, Comparative Example 7 are baths containing metal impurities). These trivalent chromium plating solutions were subjected to a Hull cell test using nickel-plated brass plates. The Hull cell test conditions are a current of 5 A and a plating time of 3 minutes. Air agitation was performed during plating. After plating, the appearance was evaluated according to the following criteria. These results are shown in Table 1. In addition, the appearance of Example 1, Example 2 and Comparative Example 1 after the Hull cell test is shown as representative results of Examples and Comparative Examples (Figs. 1 to 3).
  • Appearance evaluation> ⁇ : Appearance is uniform and there is no uneven pattern ⁇ : Appearance is uneven, or there is an uneven pattern
  • Comparative Example 1 produced a bluish uneven pattern over a wide range of current densities.
  • Comparative Example 2 black abnormal deposition occurred in the high current density portion, and the overall appearance was blurred.
  • Comparative Example 3 produced a white cloudy pattern in the high current density area and a black spotty pattern in the low current density area.
  • Comparative Example 4 produced a white uneven pattern in the low current density portion.
  • Comparative Example 5 a brown uneven pattern was generated on the whole, and the plating itself was hardly deposited.
  • gelation occurred at the stage of preparing the solution, so the plating test itself could not be performed.
  • Comparative Example 7 produced a brown striped pattern in the middle to low current density areas.
  • the trivalent chromium plating of the present invention can be used for various purposes like plating using hexavalent chromium.

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Abstract

Provided is a trivalent chromium plating solution comprising a trivalent chromium compound, a complexing agent, and a conductive salt, and characterized by further comprising a compound represented by general formula (I) (where, in formula (I), R1 is hydrogen, an optionally substituted benzyl group, or an optionally branched C1-C10 alkyl group, hydroxyalkyl group, or carboxyalkyl group; R2 is hydrogen, optionally branched C1-C5 alkyl group or carboxyalkyl group; and R3 is hydrogen, optionally branched C1-C5 alkyl group or carboxyalkyl group), and one or more selected from an alkali metallic salt of the compound and a hydrate of the alkali metallic salt. Also provided are a method for trivalent chromium plating and a chromium-plated product in which said trivalent chromium plating solution is used. A method for improving the resistance to metal impurities for a trivalent chromium plating solution is a novel approach to block the influence of metal impurities.

Description

３価クロムメッキ液およびこれを用いたクロムメッキ方法Trivalent chromium plating solution and chromium plating method using the same
　本発明は、３価クロムメッキ液およびこれを用いたクロムメッキ方法に関するものである。 The present invention relates to a trivalent chromium plating solution and a chromium plating method using the same.
　クロムメッキは、銀白色の外観を有するため装飾用のコーティング膜として用いられている。このクロムメッキには６価のクロムが用いられていたが、近年ではこの６価のクロムが環境に影響を及ぼすため、その使用が制限されてきており、３価のクロムを用いる技術へシフトしてきている。 Chrome plating is used as a decorative coating film because it has a silver-white appearance. Hexavalent chromium was used for this chrome plating, but in recent years, this hexavalent chromium has an adverse effect on the environment, so its use has been restricted, and there has been a shift to technology that uses trivalent chromium. ing.
　また、３価クロムメッキ液は、６価クロムメッキ液と比べて金属不純物に影響されやすいため、３価クロムメッキ液中から金属不純物を除去する技術が要求され、それらが報告されている。例えば、特許文献１にはフェロシアン化物により３価クロムメッキ液中の金属不純物を沈殿させて濾過等で金属不純物を除去する技術が、特許文献２には、金属不純物を含む３価クロムメッキ液を、クロムメッキ処理時の陰極電流密度と比較して低い電流密度で電解する技術が、特許文献３では、イミノ二酢酸型のイオン交換樹脂を通して、金属不純物を除去する技術が報告されている。 In addition, since trivalent chromium plating solutions are more susceptible to metal impurities than hexavalent chromium plating solutions, techniques for removing metal impurities from trivalent chromium plating solutions are required and have been reported. For example, Patent Document 1 describes a technique of precipitating metal impurities in a trivalent chromium plating solution with ferrocyanide and removing the metal impurities by filtration or the like, and Patent Document 2 describes a trivalent chromium plating solution containing metal impurities. is electrolyzed at a lower current density than the cathodic current density during chromium plating, and Patent Document 3 reports a technique for removing metal impurities through an iminodiacetic acid type ion exchange resin.
　しかしながら、上記技術では濾過、電気分解等の３価クロムメッキ液から金属不純物を除去するための工程や金属不純物を除去するために用いられる樹脂の再生処理工程等が必須であり、より簡便な技術が求められていた。 However, the above technique requires a process for removing metal impurities from the trivalent chromium plating solution such as filtration and electrolysis, and a process for regenerating the resin used for removing metal impurities. was sought.
特開昭６０－１５５６９４号公報JP-A-60-155694 特開２００９－２１５５８１号公報JP 2009-215581 A 特開平４－２２８５９９号公報JP-A-4-228599
　従って、本発明の課題は、３価クロムメッキ液において金属不純物の影響を受けない新たな技術を提供することである。 Therefore, an object of the present invention is to provide a new technology that is not affected by metal impurities in the trivalent chromium plating solution.
　本発明者らは、上記課題を解決するために鋭意研究した結果、３価クロムメッキ液に特定の構造の化合物を含有させることにより、上記課題を解決できることを見出し、本発明を完成させた。 As a result of intensive research to solve the above problems, the inventors found that the above problems could be solved by including a compound with a specific structure in the trivalent chromium plating solution, and completed the present invention.
　すなわち、本発明は３価クロム化合物、錯化剤、伝導性塩を含有する３価クロムメッキ液に、
　以下の一般式（Ｉ）
Figure JPOXMLDOC01-appb-C000003
 （ただし、式（Ｉ）中、Ｒ１は水素、置換されていてもよいベンジル基、あるいは分岐していてもよい炭素数１～１０のアルキル基、ヒドロキシアルキル基またはカルボキシアルキル基を示し、Ｒ２は水素、分岐していてもよい炭素数１～５のアルキル基またはカルボキシアルキル基を示し、Ｒ３は水素、分岐していてもよい炭素数１～５のアルキル基またはカルボキシアルキル基を示す）
で表される化合物、前記化合物のアルカリ金属塩および前記アルカリ金属塩の水和物から選ばれる１種または２種以上を含有することを特徴とする３価クロムメッキ液である。 That is, the present invention provides a trivalent chromium plating solution containing a trivalent chromium compound, a complexing agent, and a conductive salt,
The following general formula (I)
Figure JPOXMLDOC01-appb-C000003
 (In formula (I), R 1 represents hydrogen, an optionally substituted benzyl group, or an optionally branched alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group or a carboxyalkyl group, and R 2 represents hydrogen, an optionally branched C 1-5 alkyl group or a carboxyalkyl group, and R 3 represents hydrogen, an optionally branched C 1-5 alkyl group or a carboxyalkyl group. )
A trivalent chromium plating solution characterized by containing one or more selected from a compound represented by, an alkali metal salt of the compound and a hydrate of the alkali metal salt.
　また、本発明は被メッキ物を、上記３価クロムメッキ液で電気メッキすることを特徴とする被メッキ物への３価クロムメッキ方法である。 Further, the present invention is a method for plating an object to be plated with trivalent chromium, characterized by electroplating the object to be plated with the trivalent chromium plating solution.
　更に、本発明は被メッキ物を、上記３価クロムメッキ液で電気メッキして得られるクロムメッキ製品である。 Further, the present invention is a chromium-plated product obtained by electroplating an object to be plated with the trivalent chromium plating solution.
　また更に、本発明は３価クロム化合物、錯化剤、伝導性塩を含有する３価クロムメッキ液中に、上記一般式（Ｉ）で表される化合物、前記化合物のアルカリ金属塩および前記アルカリ金属塩の水和物から選ばれる１種または２種以上を含有させることを特徴とする３価クロムメッキ液に混入した金属不純物への耐性改善方法である。 Furthermore, the present invention provides a trivalent chromium plating solution containing a trivalent chromium compound, a complexing agent and a conductive salt, in which the compound represented by the general formula (I), an alkali metal salt of the compound and the alkali A method for improving resistance to metal impurities mixed in a trivalent chromium plating solution, characterized by containing one or more selected from hydrates of metal salts.
　本発明の３価のクロムメッキ液は、液中に金属不純物が混入しても影響を受けないため濾過、電気分解等の金属不純物を除去する工程や金属不純物を除去するために用いられる樹脂の再生処理工程等も必要ないため、生産ラインを止めずに連続でメッキをすることができる。 The trivalent chromium plating solution of the present invention is not affected even if metal impurities are mixed in the solution. Since there is no need for a regeneration treatment process, etc., plating can be continuously performed without stopping the production line.
　本発明の３価のクロムメッキ製品は、メッキ液中の金属不純物により招きうる外観不良を生じさせず、均一な金属光沢皮膜が得られる。 The trivalent chromium-plated product of the present invention does not cause appearance defects that can be caused by metal impurities in the plating solution, and a uniform metallic luster film can be obtained.
実施例１のハルセル試験の結果を示す図である。1 is a diagram showing the results of a Hull cell test of Example 1. FIG. 実施例２のハルセル試験の結果を示す図である。FIG. 10 is a diagram showing the results of a Hull cell test of Example 2; 比較例１のハルセル試験の結果を示す図である。3 is a diagram showing the results of a Hull cell test of Comparative Example 1. FIG.
　本発明の３価クロムメッキ液（以下、「本発明メッキ液」という）は、３価クロム化合物、錯化剤、伝導性塩を含有する３価クロムメッキ液に、以下の一般式（Ｉ）
Figure JPOXMLDOC01-appb-C000004
 で表される化合物、前記化合物のアルカリ金属塩および前記アルカリ金属塩の水和物（以下、これらを単に「化合物」ということもある）から選ばれる１種または２種以上を含有させたものである。 The trivalent chromium plating solution of the present invention (hereinafter referred to as "the plating solution of the present invention") comprises a trivalent chromium plating solution containing a trivalent chromium compound, a complexing agent, and a conductive salt, added with the following general formula (I):
Figure JPOXMLDOC01-appb-C000004
 One or two or more selected from compounds represented by, alkali metal salts of the compounds, and hydrates of the alkali metal salts (hereinafter, these may be simply referred to as "compounds"). be.
　一般式（Ｉ）で表される化合物中、Ｒ１は水素、置換されていてもよいベンジル基、あるいは分岐していてもよい炭素数１～１０のアルキル基、（炭素数１～１０の）ヒドロキシアルキル基または（炭素数１～１０の）カルボキシアルキル基、好ましくは水素、炭素数１～５のヒドロキシアルキル基または（炭素数１～５の）カルボキシアルキル基を示す。なお、ベンジル基の置換基としては、例えば、ヒドロキシ基等が挙げられる。また、Ｒ２は水素、分岐していてもよい炭素数１～５のアルキル基または（炭素数１～５の）カルボキシアルキル基を示し、好ましくは水素または炭素数１～５のアルキル基を示す。更に、Ｒ３は水素または分岐していてもよい炭素数１～５のアルキル基または（炭素数１～５の）カルボキシアルキル基、好ましくは水素または炭素数１～５のアルキル基を示す。また、上記化合物はナトリウム、カリウム等のアルカリ金属との塩であってもよい。これらアルカリ金属との塩の中でもナトリウム塩がより好ましい。更に、これら化合物のアルカリ金属塩は水和物であってもよい。本発明メッキ液においては、これら化合物、化合物のアルカリ金属塩、前記アルカリ金属塩の水和物から選ばれる１種または２種以上を用いることができる。 In the compound represented by the general formula (I), R 1 is hydrogen, an optionally substituted benzyl group, or an optionally branched alkyl group having 1 to 10 carbon atoms (having 1 to 10 carbon atoms) It represents a hydroxyalkyl group or a carboxyalkyl group (having 1 to 10 carbon atoms), preferably hydrogen, a hydroxyalkyl group having 1 to 5 carbon atoms or a carboxyalkyl group (having 1 to 5 carbon atoms). In addition, as a substituent of a benzyl group, a hydroxy group etc. are mentioned, for example. R 2 represents hydrogen, an optionally branched alkyl group having 1 to 5 carbon atoms or a carboxyalkyl group (having 1 to 5 carbon atoms), preferably hydrogen or an alkyl group having 1 to 5 carbon atoms. . Further, R 3 represents hydrogen, an optionally branched C 1-5 alkyl group or a (C 1-5) carboxyalkyl group, preferably hydrogen or a C 1-5 alkyl group. Moreover, the above compounds may be salts with alkali metals such as sodium and potassium. Among these salts with alkali metals, sodium salts are more preferred. Furthermore, the alkali metal salts of these compounds may be hydrates. In the plating solution of the present invention, one or more selected from these compounds, alkali metal salts of the compounds, and hydrates of the alkali metal salts can be used.
　上記化合物の具体的なものとしては、イミノ二酢酸、Ｎ－（２－ヒドロキシエチル）イミノ二酢酸、Ｎ－（１－カルボキシラトエチル）イミノ二酢酸三ナトリウム（またはこの水和物）、ニトリロ三酢酸、Ｎ－（２－カルボキシエチル）イミノ二酢酸、Ｎ－（ｏ－ヒドロキシベンジル）イミノ二酢酸、Ｎ－ベンジルイミノニ酢酸等が挙げられる。これらの中でもコストの点と水への溶解性の点からイミノ二酢酸、Ｎ－（２－ヒドロキシエチル）イミノ二酢酸、Ｎ－（１－カルボキシラトエチル）イミノ二酢酸三ナトリウム（またはこの水和物）が好ましく、イミノ二酢酸がより好ましい。 Specific examples of the above compounds include iminodiacetic acid, N-(2-hydroxyethyl)iminodiacetic acid, N-(1-carboxylatoethyl)iminodiacetic acid trisodium (or its hydrate), nitrilot Acetic acid, N-(2-carboxyethyl)iminodiacetic acid, N-(o-hydroxybenzyl)iminodiacetic acid, N-benzyliminodiacetic acid and the like. Among these, iminodiacetic acid, N-(2-hydroxyethyl)iminodiacetic acid, N-(1-carboxylatoethyl)iminodiacetic acid trisodium (or its hydrated product) is preferred, and iminodiacetic acid is more preferred.
　本発明メッキ液における、上記化合物の含有量は特に限定されないが、例えば、０．５～１０ｇ／Ｌ、好ましくは１～５ｇ／Ｌである。 Although the content of the above compound in the plating solution of the present invention is not particularly limited, it is, for example, 0.5 to 10 g/L, preferably 1 to 5 g/L.
　なお、上記化合物は、これを有効成分とすることにより、金属不純物への耐性を改善するための３価クロムメッキ液用添加剤とすることができる。この３価クロムメッキ液用添加剤は従来の３価クロムメッキ液に添加することができる。 By using the compound as an active ingredient, the compound can be used as an additive for a trivalent chromium plating solution for improving resistance to metal impurities. This additive for a trivalent chromium plating solution can be added to a conventional trivalent chromium plating solution.
　また、上記化合物を、３価クロム化合物、錯化剤、伝導性塩を含有する３価クロムメッキ液中に含有させることにより、３価クロムメッキ液に混入した金属不純物への耐性を改善することができる。そのため、従来のように、濾過、電気分解等の金属不純物を除去する工程や金属不純物を除去するために用いられる樹脂の再生処理工程等も必要ない。 Further, by including the above compound in a trivalent chromium plating solution containing a trivalent chromium compound, a complexing agent, and a conductive salt, the resistance to metal impurities mixed in the trivalent chromium plating solution is improved. can be done. Therefore, there is no need for a step of removing metal impurities such as filtration or electrolysis, or a step of regenerating the resin used for removing metal impurities, which is conventionally required.
　本発明メッキ液に用いられる３価クロム化合物は、特に限定されないが、例えば、塩基性硫酸クロム、硫酸クロム、塩化クロム、スルファミン酸クロム、酢酸クロム等であり、好ましくは塩基性硫酸クロム、硫酸クロム、塩化クロムである。これら３価クロム化合物は１種または２種以上を組み合わせてもよい。本発明メッキ液における３価クロム化合物の含有量は特に限定されないが、例えば金属クロムとして１～２５ｇ／Ｌであり、好ましくは１～１５ｇ／Ｌである。 The trivalent chromium compound used in the plating solution of the present invention is not particularly limited. , is chromium chloride. These trivalent chromium compounds may be used singly or in combination of two or more. Although the content of the trivalent chromium compound in the plating solution of the present invention is not particularly limited, it is, for example, 1 to 25 g/L, preferably 1 to 15 g/L as metallic chromium.
　本発明メッキ液に用いられる錯化剤は、特に限定されないが、例えば、ギ酸、ギ酸アンモニウム、ギ酸カリウム等の脂肪族モノカルボン酸またはその塩、コハク酸、マレイン酸、リンゴ酸、クエン酸、クエン酸三アンモニウム等の脂肪族ジカルボン酸またはその塩、酒石酸、酒石酸ジアンモニウム、酒石酸ナトリウム等のヒドロキシ基を２つ以上、カルボキシ基を２つ以上有するカルボン酸またはその塩等が挙げられる。これら錯化剤は１種または２種以上を組み合わせてもよい。本発明メッキ液における錯化剤の含有量は特に限定されないが、例えば、０．１～５０ｇ／Ｌであり、好ましくは１～３０ｇ／Ｌである。なお、上記一般式（Ｉ）で表される化合物は錯化作用を有するが本発明においては錯化剤として用いられるものではない。 The complexing agent used in the plating solution of the present invention is not particularly limited. Examples include aliphatic dicarboxylic acids such as triammonium acid or salts thereof, carboxylic acids having two or more hydroxy groups and two or more carboxy groups such as tartaric acid, diammonium tartrate, and sodium tartrate, or salts thereof. These complexing agents may be used singly or in combination of two or more. Although the content of the complexing agent in the plating solution of the present invention is not particularly limited, it is, for example, 0.1 to 50 g/L, preferably 1 to 30 g/L. Although the compound represented by the general formula (I) has a complexing action, it is not used as a complexing agent in the present invention.
　本発明メッキ液に用いられる伝導性塩は、特に限定されないが、例えば、硫酸カリウム、硫酸アンモニウム、硫酸ナトリウム等の硫酸塩、塩化カリウム、塩化アンモニウム、塩化ナトリウム等の塩化物、スルファミン酸カリウム、スルファミン酸アンモニウム、スルファミン酸ナトリウム等のスルファミン酸塩等が挙げられる。なお、これら伝導性塩はそれぞれのグループごと、例えば、硫酸塩、塩化物等のグループごとに用いられる。これら伝導性塩の中でも硫酸塩または塩化物が好ましい。これら伝導性塩は１種または２種以上を組み合わせてもよい。本発明メッキ液における伝導性塩の含有量は特に限定されないが、例えば、１００～５００ｇ／Ｌであり、好ましくは１５０～３００ｇ／Ｌである。 The conductive salt used in the plating solution of the present invention is not particularly limited, but examples include sulfates such as potassium sulfate, ammonium sulfate and sodium sulfate; chlorides such as potassium chloride, ammonium chloride and sodium chloride; Examples include ammonium, sulfamate such as sodium sulfamate, and the like. These conductive salts are used for each group, for example, for each group such as sulfates and chlorides. Among these conductive salts, sulfates or chlorides are preferred. These conductive salts may be used singly or in combination of two or more. Although the content of the conductive salt in the plating solution of the present invention is not particularly limited, it is, for example, 100 to 500 g/L, preferably 150 to 300 g/L.
　本発明メッキ液は、更にｐＨ緩衝剤を含有させることが好ましい。ｐＨ緩衝剤は、特に限定されないが、ホウ酸、ホウ酸ナトリウム、ホウ酸カリウム、リン酸、リン酸水素２カリウム等である。これらの中でもホウ酸、ホウ酸ナトリウムが好ましい。これらｐＨ緩衝剤は１種または２種以上を組み合わせてもよい。本発明メッキ液におけるｐＨ緩衝剤の含有量は特に限定されないが、例えば、２５～２００ｇ／Ｌであり、好ましくは５０～１００ｇ／Ｌである。 The plating solution of the present invention preferably further contains a pH buffer. The pH buffer is not particularly limited, but boric acid, sodium borate, potassium borate, phosphoric acid, dipotassium hydrogen phosphate and the like. Among these, boric acid and sodium borate are preferred. These pH buffers may be used singly or in combination of two or more. Although the content of the pH buffering agent in the plating solution of the present invention is not particularly limited, it is, for example, 25 to 200 g/L, preferably 50 to 100 g/L.
　本発明メッキ液には、更に、ポリエチレングリコール等の高分子化合物、アスコルビン酸、アスコルビン酸ナトリウム、過酸化水素、界面活性剤、抱水クロラール、チオシアン酸ナトリウム等を含有させてもよい。 The plating solution of the present invention may further contain polymer compounds such as polyethylene glycol, ascorbic acid, sodium ascorbate, hydrogen peroxide, surfactants, chloral hydrate, sodium thiocyanate, and the like.
　本発明メッキ液のｐＨは酸性であれば特に限定されず、例えば、２～４．５が好ましく、２．５～４．０がより好ましい。 The pH of the plating solution of the present invention is not particularly limited as long as it is acidic. For example, 2 to 4.5 is preferable, and 2.5 to 4.0 is more preferable.
　本発明メッキ液の伝導性塩が塩化物の場合（いわゆる塩化物浴）、錯化剤としては、例えば、ギ酸、ギ酸アンモニウム、ギ酸カリウム、クエン酸、クエン酸三アンモニウム等のギ酸もしくはクエン酸またはそれらの塩が挙げられる。これらの中でも、ギ酸アンモニウム、クエン酸三アンモニウムが好ましい。これら錯化剤は１種または２種以上を組み合わせて用いることができる。本発明メッキ液における錯化剤の含有量は特に限定されないが、例えば、０．５～６０ｇ／Ｌ、好ましくは１～５０ｇ／Ｌである。 When the conductive salt of the plating solution of the present invention is chloride (so-called chloride bath), the complexing agent may be formic acid or citric acid such as formic acid, ammonium formate, potassium formate, citric acid, triammonium citrate, or and salts thereof. Among these, ammonium formate and triammonium citrate are preferred. These complexing agents can be used singly or in combination of two or more. Although the content of the complexing agent in the plating solution of the present invention is not particularly limited, it is, for example, 0.5 to 60 g/L, preferably 1 to 50 g/L.
　更に、本発明メッキ液の伝導性塩が塩化物の場合、更に、臭化アンモニウム、臭化カリウム等の臭化物を含有させることが好ましい。本発明メッキ液における臭化物の含有量は特に限定されないが、例えば、０．５～６０ｇ／Ｌであり、好ましくは１～２０ｇ／Ｌである。 Furthermore, when the conductive salt of the plating solution of the present invention is a chloride, it is preferable to further contain a bromide such as ammonium bromide or potassium bromide. The bromide content in the plating solution of the present invention is not particularly limited, but is, for example, 0.5 to 60 g/L, preferably 1 to 20 g/L.
　本発明メッキ液に、伝導性塩として塩化物を用いる場合、錯化剤としてギ酸もしくはクエン酸またはそれらの塩を用いることが好ましく、更に臭化物を組合せて用いることが特に好ましい。 When chloride is used as a conductive salt in the plating solution of the present invention, it is preferable to use formic acid or citric acid or a salt thereof as a complexing agent, and it is particularly preferable to use bromide in combination.
　本発明メッキ液に、伝導性塩として塩化物を用いる場合の好ましい組成の一例としては以下のものが挙げられる。
＜組成例＞
　塩基性硫酸クロム　　　　　４５～７５ｇ／Ｌ
　　（クロム濃度：７．５～１２．５ｇ／Ｌ）
　ギ酸アンモニウム　　　　　１０～３０ｇ／Ｌ
　塩化ナトリウム　　　　　４０～１００ｇ／Ｌ
　塩化カリウム　　　　　１００～１６０ｇ／Ｌ
　塩化アンモニウム　　　　７０～１００ｇ／Ｌ
　臭化アンモニウム　　　　　　２～１２ｇ／Ｌ
　ホウ酸　　　　　　　　　　　　　６７ｇ／Ｌ A preferred example of the composition of the plating solution of the present invention when chloride is used as the conductive salt is as follows.
<Composition example>
Basic chromium sulfate 45-75g/L
(Chromium concentration: 7.5 to 12.5 g/L)
Ammonium formate 10-30g/L
Sodium chloride 40-100g/L
Potassium chloride 100-160g/L
Ammonium chloride 70-100g/L
Ammonium bromide 2-12g/L
Boric acid 67g/L
　本発明メッキ液の伝導性塩が硫酸塩の場合（いわゆる硫酸塩浴）、錯化剤としては、例えば、ヒドロキシ基を２つ以上、カルボキシ基を２つ以上有するカルボン酸またはその塩を用いることが好ましい。この錯化剤としては、例えば、酒石酸等のカルボン酸、酒石酸ジアンモニウム、ロッシェル塩、酒石酸ナトリウム等の前記カルボン酸の塩が挙げられる。これらの錯化剤の中でも酒石酸または酒石酸ジアンモニウムが好ましく、酒石酸ジアンモニウムがより好ましい。これら錯化剤は１種または２種以上を組み合わせてもよい。本発明メッキ液におけるカルボン酸またはその塩の含有量は特に限定されないが、例えば、０．１～９０ｇ／Ｌであり、好ましくは１～６０ｇ／Ｌである。 When the conductive salt of the plating solution of the present invention is a sulfate (so-called sulfate bath), the complexing agent may be, for example, a carboxylic acid having two or more hydroxy groups and two or more carboxyl groups, or a salt thereof. is preferred. Examples of the complexing agent include carboxylic acids such as tartaric acid, diammonium tartrate, Rochelle salts, and salts of the above carboxylic acids such as sodium tartrate. Among these complexing agents, tartaric acid or diammonium tartrate is preferred, and diammonium tartrate is more preferred. These complexing agents may be used singly or in combination of two or more. The content of the carboxylic acid or its salt in the plating solution of the present invention is not particularly limited, but is, for example, 0.1 to 90 g/L, preferably 1 to 60 g/L.
　本発明メッキ液の伝導性塩が硫酸塩の場合、更に、硫黄含有有機化合物を含有させることが好ましい。本発明メッキ液に用いられる硫黄含有有機化合物は、特に限定されないが、例えば、サッカリン、サッカリン酸ナトリウム等のサッカリンまたはその塩、アリルスルホン酸ナトリウム、アリルチオ尿素、２－メチルアリルスルホン酸アンモニウム、アリルイソチアシアネート等のアリル基を有する硫黄含有有機化合物、［［アミノ（イミノ）メチル］チオ］酢酸、３－［［アミノ（イミノ）メチル］チオ］プロパン酸、２－イミノチアゾリジン－４－オン、２－アミノ－５，６－ジハイドロ－４Ｈ－１，３－チアジン－４－オン等のカルバミミドイルチオ基を有するカルボン酸とその脱水反応物、チオ尿素、チオシアン酸ナトリウム等が挙げられる。 When the conductive salt of the plating solution of the present invention is a sulfate, it is preferable to further contain a sulfur-containing organic compound. The sulfur-containing organic compound used in the plating solution of the present invention is not particularly limited. Sulfur-containing organic compounds having an allyl group such as thiacyanate, [[amino(imino)methyl]thio]acetic acid, 3-[[amino(imino)methyl]thio]propanoic acid, 2-iminothiazolidin-4-one, 2 -Amino-5,6-dihydro-4H-1,3-thiazin-4-one and other carboxylic acids having a carbamimidoylthio group, dehydration products thereof, thiourea, sodium thiocyanate and the like.
　これら硫黄含有有機化合物は１種または２種以上を組み合わせてもよい。上記硫黄含有有機化合物の中でも、サッカリンまたはその塩と、アリル基を有する硫黄含有有機化合物、カルバミミドイルチオ基を有するカルボン酸および／またはその脱水反応物からなる群から選ばれる１種以上の組合せが好ましく、特にサッカリン酸ナトリウムが好ましい。本発明メッキ液における硫黄含有有機化合物の含有量は特に限定されないが、例えば、０．５～１０ｇ／Ｌであり、好ましくは２～８ｇ／Ｌである。 These sulfur-containing organic compounds may be used alone or in combination of two or more. Among the above sulfur-containing organic compounds, a combination of one or more selected from the group consisting of saccharin or a salt thereof, a sulfur-containing organic compound having an allyl group, a carboxylic acid having a carbamimidoylthio group and/or a dehydration reaction product thereof is preferred, and sodium saccharinate is particularly preferred. Although the content of the sulfur-containing organic compound in the plating solution of the present invention is not particularly limited, it is, for example, 0.5 to 10 g/L, preferably 2 to 8 g/L.
　本発明メッキ液に、伝導性塩として硫酸塩を用いる場合、錯化剤としてヒドロキシ基を２つ以上、カルボキシ基を２つ以上有するカルボン酸またはその塩を用いることが好ましく、更に硫黄含有有機化合物として、サッカリンまたはその塩を組合せて用いることが特に好ましい。 When a sulfate is used as a conductive salt in the plating solution of the present invention, it is preferable to use a carboxylic acid having two or more hydroxy groups and two or more carboxy groups or a salt thereof as a complexing agent. As, it is particularly preferred to use saccharin or a salt thereof in combination.
　本発明メッキ液に、伝導性塩として硫酸塩を用いる場合の好ましい組成の一例としては以下のものが挙げられる。
＜組成例＞
　塩基性硫酸クロム　　　　　１２～６０ｇ／Ｌ
　　（クロム濃度：２．０～１０ｇ／Ｌ）
　酒石酸ジアンモニウム　　　　３～５０ｇ／Ｌ
　硫酸カリウム　　　　　１００～２００ｇ／Ｌ
　サッカリン酸ナトリウム　　０．５～６ｇ／Ｌ
　ホウ酸　　　　　　　　　　５０～９０ｇ／Ｌ A preferred example of the composition of the plating solution of the present invention when sulfate is used as a conductive salt is as follows.
<Composition example>
Basic chromium sulfate 12-60g/L
(Chromium concentration: 2.0 to 10 g/L)
Diammonium tartrate 3-50g/L
Potassium sulfate 100-200g/L
Sodium saccharinate 0.5-6g/L
Boric acid 50-90g/L
　以上説明した本発明メッキ液の調製法は特に限定されず、例えば、４０～６０℃の水に３価クロム化合物、錯化剤、伝導性塩を添加、混合し、溶解した後に、上記化合物、必要により硫黄含有有機化合物、界面活性剤等を添加、混合し、最後に硫酸、塩酸、アンモニア水等でｐＨを調整することにより、調製することができる。 The method for preparing the plating solution of the present invention described above is not particularly limited. It can be prepared by adding and mixing a sulfur-containing organic compound, a surfactant, etc., if necessary, and finally adjusting the pH with sulfuric acid, hydrochloric acid, aqueous ammonia, or the like.
　本発明メッキ液は、従来のクロムメッキ液と同様に、被メッキ物を本発明メッキ液で電気メッキすることにより被メッキ物へクロムメッキをすることができる。 The plating solution of the present invention can plate an object to be plated with chromium by electroplating the object to be plated with the plating solution of the present invention in the same manner as the conventional chrome plating solution.
　なお、本発明メッキ液は、メッキ時に金属不純物が混入しても外観に悪影響を与えず、かつ、濾過や電気分解等の金属不純物を除去する操作が必要なく、そのまま生産ラインを止めずに連続してメッキを行うことができる。ここで金属不純物は、下地にされるメッキやその他メッキに付随する薬品等に由来する金属である。具体的な金属としては、例えば、ニッケル、亜鉛、銅、６価のクロム等が挙げられ、好ましくは下地メッキに用いられることが多いニッケルまたは銅である。また、本発明メッキ液が影響を受けない金属不純物の含有量は特に限定されないが、例えば、０～２００ｍｇ／Ｌ、好ましくは０～１００ｍｇ／Ｌである。 The plating solution of the present invention does not adversely affect the appearance even if metal impurities are mixed in during plating, and does not require operations to remove metal impurities such as filtration and electrolysis, and can be used continuously without stopping the production line. can be plated. Here, the metal impurities are metals derived from the underlying plating and other chemicals associated with the plating. Specific metals include, for example, nickel, zinc, copper, hexavalent chromium, etc. Nickel and copper, which are often used for base plating, are preferred. The content of metal impurities that does not affect the plating solution of the present invention is not particularly limited, but is, for example, 0 to 200 mg/L, preferably 0 to 100 mg/L.
　電気メッキの条件は特に限定されないが、例えば、浴温は３０～６０℃、硫酸塩浴の場合には５０～６０℃が好ましく、塩化物浴の場合は３０～４０℃が好ましく、アノードがカーボンあるいは酸化イリジウム、陰極電流密度が２～２０Ａ／ｄｍ２で１～１５分間電気メッキを行えばよい。 The conditions for electroplating are not particularly limited. Alternatively, iridium oxide may be electroplated at a cathode current density of 2-20 A/dm 2 for 1-15 minutes.
　電気メッキすることのできる被メッキ物としては、例えば、鉄、ステンレス、真鍮等の金属、ＡＢＳ、ＰＣ／ＡＢＳ等の樹脂が挙げられる。なお、この被メッキ物は本発明のメッキ液で処理する前に予め銅メッキ、ニッケルメッキ等の処理をしておいてもよい。 Examples of objects that can be electroplated include metals such as iron, stainless steel, and brass, and resins such as ABS and PC/ABS. The object to be plated may be plated with copper, nickel or the like before being treated with the plating solution of the present invention.
　被メッキ物にニッケルメッキ処理をする場合には、常法に従って３層または４層のニッケルメッキ層を設けることが好ましい。３層の場合、半光沢ニッケルメッキ、光沢ニッケルメッキ、マイクロポーラスニッケルメッキの順に層を設ければよい。この際、各層の電位差は特に限定されないが、例えば、半光沢ニッケルメッキに対して、光沢ニッケルメッキの電位差を－２００～－６０ｍＶ、光沢ニッケルメッキに対して、マイクロポーラスニッケルメッキの電位差を２０～１００ｍＶにすることが好ましい。４層の場合、半光沢ニッケルメッキ、高硫黄含有ニッケルメッキ、光沢ニッケルメッキ、マイクロポーラスニッケルメッキの順に層を設ければよい。この際、各層の電位差は特に限定されないが、例えば、半光沢ニッケルメッキに対して、光沢ニッケルメッキの電位差を－２００～－６０ｍＶ、光沢ニッケルメッキに対して、高硫黄含有ニッケルメッキの電位差を－５０～－５ｍＶ、光沢ニッケルメッキに対して、マイクロポーラスニッケルメッキの電位差を２０～１００ｍＶの範囲にすることが好ましい。 When nickel plating an object to be plated, it is preferable to provide three or four nickel plating layers according to a conventional method. In the case of three layers, the layers may be provided in order of semi-bright nickel plating, bright nickel plating, and microporous nickel plating. At this time, the potential difference between each layer is not particularly limited. 100 mV is preferred. In the case of four layers, the layers may be provided in order of semi-bright nickel plating, high sulfur content nickel plating, bright nickel plating, and microporous nickel plating. At this time, the potential difference of each layer is not particularly limited. 50 to -5 mV, and the potential difference of the microporous nickel plating to the bright nickel plating is preferably in the range of 20 to 100 mV.
　斯くして得られるクロムメッキ製品は、装飾性に優れた金属光沢を有し、耐食性に優れる皮膜を有するものとなる。 The chromium-plated product thus obtained has a highly decorative metallic luster and a coating with excellent corrosion resistance.
　更に、このクロムメッキには、クロメート処理を行ってもよい。これにより耐食性が向上する。 Furthermore, this chrome plating may be subjected to chromate treatment. This improves corrosion resistance.
　クロメート処理の条件は特に限定されないが、例えば、浴温が２５～７０℃、アノードが鉛すず合金等の不溶性陽極、陰極電流密度が０．１～１Ａ／ｄｍ２で１分間通電処理を行えばよい。 The conditions for the chromate treatment are not particularly limited. good.
　以下、本発明を実施例を挙げて詳細に説明するが、本発明はこれら実施例に何ら限定されるものではない。 Although the present invention will be described in detail below with reference to examples, the present invention is not limited to these examples.
実施例１～１０および比較例１～７
　　　クロムメッキ：
　表１に記載の化合物をそれぞれ水に溶解して、３価クロムメッキ液を調製した（実施例１～８、比較例１～６は塩化物浴、実施例９～１０、比較例７は硫酸塩浴、実施例２～８、実施例１０、比較例１～４、比較例７は金属不純物を入れた浴である）。これらの３価クロムメッキ液について、ニッケルメッキを施した真鍮板を用いてハルセル試験を行った。ハルセル試験の条件は電流５Ａ、メッキ時間３分である。なお、メッキ中は空気撹拌を行った。メッキ後、以下の基準で外観を評価した。これらの結果を表１に示した。また、実施例１、実施例２および比較例１のハルセル試験後の外観を実施例および比較例の代表的な結果として示す（図１～３）。 Examples 1-10 and Comparative Examples 1-7
Chrome-plated:
A trivalent chromium plating solution was prepared by dissolving each of the compounds listed in Table 1 in water (Examples 1 to 8 and Comparative Examples 1 to 6 were chloride baths, Examples 9 to 10 and Comparative Example 7 were sulfuric acid Salt bath, Examples 2-8, Example 10, Comparative Examples 1-4, Comparative Example 7 are baths containing metal impurities). These trivalent chromium plating solutions were subjected to a Hull cell test using nickel-plated brass plates. The Hull cell test conditions are a current of 5 A and a plating time of 3 minutes. Air agitation was performed during plating. After plating, the appearance was evaluated according to the following criteria. These results are shown in Table 1. In addition, the appearance of Example 1, Example 2 and Comparative Example 1 after the Hull cell test is shown as representative results of Examples and Comparative Examples (Figs. 1 to 3).
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
＜外観評価＞
　　○：外観が均一であり、かつムラ模様がない
　　×：外観が不均一、あるいはムラ模様がある <Appearance evaluation>
○: Appearance is uniform and there is no uneven pattern ×: Appearance is uneven, or there is an uneven pattern
　全ての実施例は、いずれも被メッキ部分において均一な光沢外観の皮膜が得られ、むら模様等は見られなかった。また、実施例において金属不純物の影響は見られなかった。一方、比較例１は広い電流密度範囲にて青っぽいむら模様が生じた。比較例２は高電流密度部において黒い異常析出が生じ、全体的に白ぼけた外観になった。比較例３は高電流密度部において白い曇り模様が生じ、さらに低電流密度部で黒いむら模様が生じた。比較例４は低電流密度部において白いむら模様が生じた。比較例５は全体的に茶色のむら模様が生じ、メッキ自体ほとんど析出していなかった。比較例６は溶液を調整した段階でゲル化したため、メッキ試験自体できなかった。比較例７は中～低電流密度部において、茶色の縞模様が生じた。 In all the examples, films with a uniform glossy appearance were obtained on the parts to be plated, and no uneven patterns were observed. In addition, no influence of metal impurities was observed in the examples. On the other hand, Comparative Example 1 produced a bluish uneven pattern over a wide range of current densities. In Comparative Example 2, black abnormal deposition occurred in the high current density portion, and the overall appearance was blurred. Comparative Example 3 produced a white cloudy pattern in the high current density area and a black spotty pattern in the low current density area. Comparative Example 4 produced a white uneven pattern in the low current density portion. In Comparative Example 5, a brown uneven pattern was generated on the whole, and the plating itself was hardly deposited. In Comparative Example 6, gelation occurred at the stage of preparing the solution, so the plating test itself could not be performed. Comparative Example 7 produced a brown striped pattern in the middle to low current density areas.
　本発明の３価クロムメッキは、６価のクロムを用いたメッキと同様に各種用途に用いることができる。 The trivalent chromium plating of the present invention can be used for various purposes like plating using hexavalent chromium.

Claims (7)

  1. 　３価クロム化合物、錯化剤、伝導性塩を含有する３価クロムメッキ液に、
    　以下の一般式（Ｉ）
    Figure JPOXMLDOC01-appb-C000001
     （ただし、式（Ｉ）中、Ｒ１は水素、置換されていてもよいベンジル基、あるいは分岐していてもよい炭素数１～１０のアルキル基、ヒドロキシアルキル基またはカルボキシアルキル基を示し、Ｒ２は水素、分岐していてもよい炭素数１～５のアルキル基またはカルボキシアルキル基を示し、Ｒ３は水素、分岐していてもよい炭素数１～５のアルキル基またはカルボキシアルキル基を示す）
    で表される化合物、前記化合物のアルカリ金属塩および前記アルカリ金属塩の水和物から選ばれる１種または２種以上を含有することを特徴とする３価クロムメッキ液。     In a trivalent chromium plating solution containing a trivalent chromium compound, a complexing agent, and a conductive salt,
    The following general formula (I)
    Figure JPOXMLDOC01-appb-C000001
     (In formula (I), R 1 represents hydrogen, an optionally substituted benzyl group, or an optionally branched alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group or a carboxyalkyl group, and R 2 represents hydrogen, an optionally branched C 1-5 alkyl group or a carboxyalkyl group, and R 3 represents hydrogen, an optionally branched C 1-5 alkyl group or a carboxyalkyl group. )
    A trivalent chromium plating solution characterized by containing one or more selected from a compound represented by the following, an alkali metal salt of the compound and a hydrate of the alkali metal salt.
  2. 　式（Ｉ）で表される化合物、前記化合物のアルカリ金属塩および前記アルカリ金属塩の水和物が、イミノ二酢酸、Ｎ－（２－ヒドロキシエチル）イミノ二酢酸またはＮ－（１－カルボキシラトエチル）イミノ二酢酸三ナトリウムまたはＮ－（２－ヒドロキシエチル）イミノ二酢酸またはＮ－（１－カルボキシラトエチル）イミノ二酢酸三ナトリウムの水和物である請求項１記載の３価クロムメッキ液。 The compound represented by formula (I), the alkali metal salt of said compound and the hydrate of said alkali metal salt are iminodiacetic acid, N-(2-hydroxyethyl)iminodiacetic acid or N-(1-carboxylate The trivalent chromium plating solution according to claim 1, which is a hydrate of trisodium ethyl)iminodiacetate, N-(2-hydroxyethyl)iminodiacetic acid, or trisodium N-(1-carboxylatoethyl)iminodiacetate. .
  3. 　伝導性塩が、塩化物であり、
    　錯化剤が、ギ酸もしくはクエン酸またはそれらの塩である請求項１または２記載の３価クロムメッキ液。     the conductive salt is a chloride,
    3. The trivalent chromium plating solution according to claim 1, wherein the complexing agent is formic acid or citric acid or a salt thereof.
  4. 　伝導性塩が、硫酸塩であり、
    　錯化剤が、ヒドロキシ基を２つ以上、カルボキシ基を２つ以上有するカルボン酸またはその塩である請求項１または２記載の３価クロムメッキ液。     the conductive salt is a sulfate,
    3. The trivalent chromium plating solution according to claim 1, wherein the complexing agent is a carboxylic acid having two or more hydroxy groups and two or more carboxy groups or a salt thereof.
  5. 　被メッキ物を、請求項１～４の何れか１項に記載の３価クロムメッキ液で電気メッキすることを特徴とする被メッキ物への３価クロムメッキ方法。 A method for trivalent chromium plating on an object to be plated, characterized by electroplating the object to be plated with the trivalent chromium plating solution according to any one of claims 1 to 4.
  6. 　被メッキ物を、請求項１～４の何れか１項に記載の３価クロムメッキ液で電気メッキして得られるクロムメッキ製品。 A chromium-plated product obtained by electroplating an object to be plated with the trivalent chromium plating solution according to any one of claims 1 to 4.
  7. 　３価クロム化合物、錯化剤、伝導性塩を含有する３価クロムメッキ液中に、以下の一般式（Ｉ）
    Figure JPOXMLDOC01-appb-C000002
     （ただし、式（Ｉ）中、Ｒ１は水素、置換されていてもよいベンジル基、あるいは分岐していてもよい炭素数１～１０のアルキル基、ヒドロキシアルキル基またはカルボキシアルキル基を示し、Ｒ２は水素、分岐していてもよい炭素数１～５のアルキル基またはカルボキシアルキル基を示し、Ｒ３は水素、分岐していてもよい炭素数１～５のアルキル基またはカルボキシアルキル基を示す）
    で表される化合物、前記化合物のアルカリ金属塩および前記アルカリ金属塩の水和物から選ばれる１種または２種以上を含有させることを特徴とする３価クロムメッキ液に混入した金属不純物への耐性改善方法。     In a trivalent chromium plating solution containing a trivalent chromium compound, a complexing agent, and a conductive salt, the following general formula (I)
    Figure JPOXMLDOC01-appb-C000002
     (In formula (I), R 1 represents hydrogen, an optionally substituted benzyl group, or an optionally branched alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group or a carboxyalkyl group, and R 2 represents hydrogen, an optionally branched C 1-5 alkyl group or a carboxyalkyl group, and R 3 represents hydrogen, an optionally branched C 1-5 alkyl group or a carboxyalkyl group. )
    To the metal impurities mixed in the trivalent chromium plating solution, characterized by containing one or more selected from the compound represented by, the alkali metal salt of the compound and the hydrate of the alkali metal salt method of improving tolerance.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55119192A (en) * 1979-03-09 1980-09-12 Toyo Soda Mfg Co Ltd Trivalent chromium plating bath
CN105671599A (en) * 2016-04-11 2016-06-15 济南德锡科技有限公司 Sulfate trivalent chromium electroplating solution and preparation method thereof
CN109652827A (en) * 2019-01-16 2019-04-19 陈建平 A kind of trivalent chromium sulfate plating solution and its manufacture craft and electroplating technology
CN110512240A (en) * 2019-09-04 2019-11-29 广东涂乐师新材料科技有限公司 A kind of white chromium electrodeposit liquid of salt acid type highly corrosion resistant trivalent

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55119192A (en) * 1979-03-09 1980-09-12 Toyo Soda Mfg Co Ltd Trivalent chromium plating bath
CN105671599A (en) * 2016-04-11 2016-06-15 济南德锡科技有限公司 Sulfate trivalent chromium electroplating solution and preparation method thereof
CN109652827A (en) * 2019-01-16 2019-04-19 陈建平 A kind of trivalent chromium sulfate plating solution and its manufacture craft and electroplating technology
CN110512240A (en) * 2019-09-04 2019-11-29 广东涂乐师新材料科技有限公司 A kind of white chromium electrodeposit liquid of salt acid type highly corrosion resistant trivalent

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