JP2011527381A - Improved copper-tin electrolyte and bronze layer deposition method - Google Patents

Abstract

Consumer goods and industrial articles are electroplated with bronze layers for decorative purposes and for protection against corrosion. The electrolytes used hitherto for producing decorative bronze layers are cyanide-containing or, as in the case of baths based on organosulfonic acids, highly corrosive, or, as in the case of cyanide-free baths based on diphosphoric acid, give unsatisfactory brightness and shine. The present invention provides a nontoxic electrolyte for the electrochemical deposition of uniformly bright and shiny bronze layers and a corresponding process for the application of such decorative bronze layers to consumer goods and industrial articles, by means of which relatively thick bronze layers can also be deposited electrochemically in a satisfactory way.

Description

  The present invention relates to toxic components, such as cyanide-free copper-tin electrolytes. In particular, the present invention relates to a corresponding electrolyte having a new brightener system. The present invention also includes a method for depositing decorative white and yellow bronze layers on consumer goods and industrial products using the electrolyte of the present invention.

  Consumer goods or products defined in the consumer product regulations are finished with a thin, oxidatively stable metal layer for decorative reasons and corrosion protection. These layers must be mechanically stable and should not show any discoloration or signs of wear even over extended use. Sales of consumer goods coated with nickel-containing finishing alloys are no longer permitted in Europe since 2001, or only under strict rules, according to European directive EU directive 94/27 / EC This is because nickel and the nickel-containing metal layer serve as allergens. Bronze alloys are increasingly being established as alternatives for finishing layers, particularly containing nickel, and these include, for example, low cost finishing of consumer goods by mass production by barrel- or rack-electroplating methods, allergens It makes it possible to provide attractive products that are free of any problems.

In the production of bronze layers for the electronics industry, the solderability of the resulting layer and optionally its mechanical bond strength are important properties of the layer to be produced. For use in this area, the appearance of this layer is generally less important compared to its function. On the other hand, for example for the production of bronze layers on consumer goods, the decorative effect of the resulting layers as well as long-term durability with an essentially unchanged appearance are important target parameters.

In addition to the usual method for producing bronze layers using a cyanide-containing and thereby highly toxic alkaline bath, according to the composition of the electrolyte, there are usually two major ones found in the prior art. Various electroplating methods are also known which can be one of the group: a method using an organosulfonic acid based electrolyte or a bath based on diphosphoric acid (pyrophosphate). Method. For the purposes of the present invention, “non-toxic” means that the electrolyte described herein according to the present invention is “toxic (T)” or under the regulations for handling hazardous materials and hazardous materials applied in Europe. It means not containing any material classified as "very toxic (T ⁺ )".

  For example, EP 1 111 097 A2 describes an electrolyte solution containing a dispersant and a whitening additive together with an organosulfonic acid and tin and copper ions and, where appropriate, an antioxidant. . EP 1 408 141 A1 describes an electrochemical deposition method of bronze, in which an acidic electrolyte contains an alkyl sulfonic acid and an aromatic nonionic wetting agent together with tin and copper ions. contains. DE 100 46 600 A1 describes an alkylsulfonic acid or alkanolsulfonic acid-containing bath containing an organic sulfur compound together with soluble tin and copper salts and a method of using the bath.

  A significant disadvantage of electrolytes produced on the basis of such organosulfonic acids is high corrosivity. For example, methanesulfonic acid based baths often have pH values below 1. The high corrosivity of these baths limits the range of use for the substrate material to be finished and requires the use of a particularly corrosion-resistant work material in order to carry out the method.

  EP 1 146 148 A2 describes a cyanide-free copper-tin electrolyte based on diphosphate, wherein in addition to the reaction product of amine and epichlorohydrin, 1: 1 Contains cationic surfactant in molar ratio. WO 2004/005528 describes cyanide-free diphosphate-copper-tin electrolytes containing additives consisting of amine derivatives, epichlorohydrin and glycidyl ether compounds. Nitric acid-based electrolytes generally have very limited long-term stability and often need to be replaced.

  Further, the method for producing a solderable copper-tin layer can be used as an alternative to tin-lead solders, and that a wide selection of acidic based electrolytes can be used in the electronics industry. Known in Thus, EP 1 001 054 A2 includes water-soluble tin salts, water-soluble copper salts, inorganic or organic acids or water-soluble salts thereof, and in addition, generally toxic thioureas or thiols A tin-copper electrolyte is described that contains one or more compounds from the group consisting of derivatives. The bath according to the invention described here can additionally be one or more selected from the group consisting of carboxylic acids, lactones, phosphoric acid condensates, phosphonic acid derivatives or their water-soluble salts or combinations thereof. The above compounds can be contained.

  W02004 / 005528 is a cyanide-free phosphate-copper-comprising an additive consisting of an amine derivative, epichlorohydrin and a glycidyl ether compound in a molar ratio of 1: 0.5-2: 0.1-5. A tin electrolyte is described. The object described in this document is to broaden the current range in a range where uniform deposition of the metal in the gloss layer can be achieved. Such precipitation can be obtained only when the additive to be added consists of all three of the above components.

  In the prior art, these deposition methods ensure uniform deposition of the metal over a wide current density range, and it is particularly advantageous to use an electrolyte that is economically and environmentally advantageous in terms of composition. Can be shown. Furthermore, an advantageous electrolyte must be able to obtain a uniform brightness and gloss layer, depending on the thickness of the deposited bronze layer.

  The object of the present invention is therefore to provide an electrolyte that is stable over time, in which case the electrolyte is a bronze layer that is mechanically stable and decoratively advantageous in consumer goods and industrial products. Suitable for advantageous precipitation and free of toxic components. A further object of the present invention is to provide a method for applying a decorative bronze layer to consumer goods and industrial products using such an electrolyte.

  These problems and the problems which are not mentioned here but which are clearly derived from the prior art, are achieved by the use of the electrolytic solution having the characteristics according to claim 1 and its use in the deposition method according to the invention of claim 13. Can do. Preferred embodiments in which these claims are cited are described in claims 2-12 and 14 and 15.

  Contains a metal to be deposited in the form of a water-soluble salt, and further contains one or more phosphonic acid derivatives as complexing agents, and further comprises a disulfide compound and a carbonate or bicarbonate. The provision of a non-toxic electrolyte solution for depositing a decorative bronze alloy layer on consumer goods and industrial products containing a whitener system advantageously accomplishes the above-mentioned problems, albeit quite surprising. The electrolytic solution according to the present invention has a composition different from that of the prior art, and it is possible to obtain remarkable electrolytic deposition of the bronze layer. In particular, good brightness and gloss of the bronze layer can be obtained regardless of its thickness. The alloy composition remains approximately constant over a wide current density range, which is not suggested in the prior art.

  In the electrolytic solution of the present invention, metallic copper and tin to be deposited or copper, tin and zinc are present as dissolved ions. These are preferably in the form of water-soluble salts, preferably pyrophosphates, carbonates, hydroxide-carbonates, bicarbonates, sulfides, sulfates, phosphates, nitrates, nitrites, halides. Introducing one selected from the group consisting of hydroxides, oxide-hydroxides, oxides or combinations thereof. Particularly preferably, the metal is in the form of a salt comprising an ion selected from the group consisting of pyrophosphate ion, carbonate ion, hydroxide-carbonate ion, oxide-hydroxide ion, hydroxide ion and bicarbonate ion. It is an embodiment used in. The color of the resulting decorative bronze layer can be determined by the amount of salt introduced into the electrolyte and can be adjusted according to customer requirements. As indicated above, the metal to be deposited is present in an ionically dissolved form in the electrolyte to apply a decorative bronze layer to consumer goods and industrial products. The ion concentration of copper can be adjusted to 0.2 to 10 g / l, preferably 0.3 to 4 g / l with respect to the electrolytic solution, and the ion concentration of tin is 1.0 to 1.0 with respect to the electrolytic solution. It can be adjusted to a range of 30 g / l, preferably 2-20 g / l, and when present, the ion concentration of zinc is 1.0-20 g / l, preferably 0 It can be adjusted to 3 g / l. For the finishing of consumer goods, the metal to be deposited is particularly preferably as pyrophosphate, carbonate, hydrogen carbonate or hydroxide-carbonate, with a resulting ion concentration of 0. Introduced to be 3-4 g copper, 2-20 g tin and 0-3 g zinc.

  The electrolyte according to the present invention has any concentration of carbonate ions or bicarbonate ions. These are preferably in the electrolyte, preferably in the form of soluble salts, selected from the group consisting of alkali metals and alkaline earth metals, in particular sodium carbonate or potassium carbonate or sodium hydrogen carbonate or potassium hydrogen carbonate. Can exist. However, it is preferred that the metal to be used and to be deposited be added completely or partly in the form of a carbonate or bicarbonate to the electrolyte. An embodiment in which only copper is present as a carbonate in the bath composition is advantageous. During the bath operation, tin and zinc and also copper are advantageously added subsequently as phosphates. The addition of the salt makes it possible to adjust the concentration of carbonate ions or bicarbonate ions in the electrolyte to 0.5 to 100 g / l with respect to 1 l of the electrolyte. The concentration is particularly preferably from 5 to 40 g / l and very particularly preferably from 15 to 30 g / l.

［式中、Ｒ及びＲ’はそれぞれ互いに独立して、置換又は非置換の（Ｃ_１〜Ｃ_８）−アルキル、（Ｃ_３〜Ｃ_６）−シクロアルキル、（Ｃ_７〜Ｃ_１９）−アルキルアリール、（Ｃ_６〜Ｃ_１８）アリール、（Ｃ_７〜Ｃ_１９）アルアルキル、（Ｃ_３〜Ｃ_１８）ヘテロアリール、（Ｃ_４〜Ｃ_１９）アルキルヘテロアリール、（Ｃ_４〜Ｃ_１９）ヘテロアルアルキルである］のものが好ましい。Ｒ及びＲ’はさらに一緒になって結合して環を形成してもよい。Ｒ及びＲ’に関する置換基として考えられる基は、原則としてこの目的のために当業者が考えることができる置換基のすべての群である。これは特に、アミン基、ニトロ基、ヒドロキシル基、ハロゲン化物基、酸基、たとえばカルボン酸基、スルホン酸基及びホスホン酸基である。 As another component of the electrolytic solution, a component made of a disulfide compound may be mentioned. These can advantageously be selected from the group consisting of substituted and unsubstituted bisalkyl or bis (hetero) aryl or alkyl (hetero) aryl disulfides, in particular of the general formula (I)

[Wherein, R and R ′ are each independently a substituted or unsubstituted (C ₁ -C ₈ ) -alkyl, (C ₃ -C ₆ ) -cycloalkyl, (C ₇ -C ₁₉ ) -alkyl. _{aryl, (C} 6 _{~C 18) aryl, (C} 7 _{~C 19) aralkyl, (C} 3 _{~C 18) heteroaryl, (C} 4 _{~C 19) alkylheteroaryl, (C} 4 _{~C 19)} heteroaryl Aralkyl] is preferred. R and R ′ may further be bonded together to form a ring. The groups considered as substituents for R and R ′ are in principle all groups of substituents that can be considered by a person skilled in the art for this purpose. This is in particular amine groups, nitro groups, hydroxyl groups, halide groups, acid groups such as carboxylic acid groups, sulfonic acid groups and phosphonic acid groups.

  Particularly advantageous disulfide compounds are 2,2′-dithiodipyridine, 4,4′-dithiodipyridine, 6,6′-dithiodinicotinic acid, bis (4-aminophenyl) disulfide, 2,2′-dithio. It is a compound selected from the group consisting of salicylic acid, D-cysteine, L-cysteine, DL-cysteine, 2,2′-dithio (bis) benzothiazole, 2,2′-dithiobis (5-nitropyridine). Particularly preferred in this context is a bis (3-sodium sulfopropyl) disulfide compound, which is abbreviated as SPS. The disulfide compound is preferably used in an amount of 0.01 mg to 10.0 g / l with respect to 1 l of the electrolytic solution. Particularly preferably, it is used in a concentration range of 0.5 mg / l to 7.5 g / l with respect to 1 l of the electrolytic solution. The disulfide compound, in particular the SPS, is very preferably used in a concentration range of 0.1 mg to 5 g / l with respect to 1 l of the electrolyte.

  The application of the decorative bronze layer to consumer goods and industrial products with the electrolyte according to the invention is carried out in the electroplating method as described above. Here, it is important that the metal to be deposited remains unchanged in the solution in the process, regardless of whether electroplating is carried out in a continuous or batch process. In order to guarantee this, the electrolytic solution of the present invention contains phosphonic acid as a complexing agent.

  Preferably, hydroxyphosphonic acid, nitrilophosphonic acid or aminophosphonic acid, such as 1-aminomethylphosphonic acid AMP, aminotris (methylenephosphonic acid) ATMP, 1,5-aminoethylphosphonic acid AEP, 1-aminopropylphosphonic acid APP, (1-acetylamino-2,2,2-trichloroethyl) phosphonic acid, (1-amino-1-phosphonooctyl) phosphonic acid, (1-benzoylamino-2,2,2-trichloroethyl) phosphonic acid, (1-benzoylamino-2,2-dichlorovinyl) phosphonic acid, (4-chlorophenylhydroxymethyl) phosphonic acid, diethylenetriaminepenta (methylenephosphonic acid) DTPMP, ethylenediaminetetra (methylenephosphonic acid) EDTMP, 1-hydroxyethane (1 , 1, Diphosphonic acid) HEDP, hydroxyethylamino-di (methylenephosphonic acid) HEMPA, hexamethylenediaminetetra (methylphosphonic acid) HDTMP, ((hydroxymethylphosphonomethylamino) methyl) phosphonic acid, nitrile tris (methylenephosphonic acid) NTMP, It is selected from the group consisting of 2,2,2-trichloro-1- (furan-2-carbonyl) aminoethylphosphonic acid, salts derived therefrom and condensates derived therefrom or combinations thereof.

Particularly preferably, aminotris (methylenephosphonic acid) ATMP, diethylenetriaminepenta (methylenephosphonic acid) DTPMP, ethylenediaminetetra (methylenephosphonic acid) EDTP, 1-hydroxyethane (1,1-diphosphonic acid) HEDP, hydroxyethylamino-di One or more compounds selected from the group consisting of (methylenephosphonic acid) HEMPA, hexamethylenediaminetetra (methylphosphonic acid) HDTMP, salts derived therefrom and condensates derived therefrom or combinations thereof use.
Preferably, 10 to 400 g of phosphonic acid derivative with respect to 1 liter of electrolytic solution, particularly preferably 20 to 200 g of phosphonic acid derivative with respect to 1 liter of electrolytic solution, and more preferably 50 to 150 g of phosphonic acid derivative with respect to 1 liter of electrolytic solution. Is used.

  The pH of the electrolyte is in the range of 6 to 14 required for electroplating. Preferably it is in the range of 8-12, and very preferably about 10.

  In addition to the metal to be deposited, the phosphonic acid derivative used as the complexing agent and the whitening agent comprising the bicarbonate and disulfide compound used, the electrolyte is further organic, which can be considered as a complexing ligand. Additives, brighteners, wetting agents or stabilizers may be included. The electrolytic solution of the present invention can further omit the use of a cationic surfactant. The addition of other brighteners and wetting agents is preferred only if the appearance of the decorative bronze layer to be deposited should meet special requirements. This makes it possible to adjust the gloss of the layer in all grades from matte silk to high gloss, as well as the color of the bronze layer, which depends strictly on the proportion of metal to be deposited.

  Preferably, one or more compounds selected from the group consisting of monocarboxylic and dicarboxylic acids and salts thereof, sulfonic acids and salts thereof, betaines and aromatic nitro compounds are added. These compounds act as electrolyte bath stabilizers. Particular preference is given to using oxalic acid, alkanesulphonic acid, particularly preferably methanesulphonic acid, or nitrobenzotriazole or mixtures thereof. Suitable alkane sulfonic acids are disclosed, for example, in EP 1001054.

［式中、Ｒは置換又は非置換の（Ｃ_１〜Ｃ_８）アルキル、（Ｃ_３〜Ｃ_６）シクロアルキル、（Ｃ_７〜Ｃ_１９）アルキルアリール、（Ｃ_６〜Ｃ_１８）アリール、（Ｃ_７〜Ｃ_１９）アルアルキル、（Ｃ_３〜Ｃ_１８）ヘテロアリール、（Ｃ_４〜Ｃ_１９）アルキルヘテロアリール、（Ｃ_４〜Ｃ_１９）ヘテロアルアルキルである］のスルホン酸又はこれらの塩を使用することも有利である。Ｒ及びＲ’に関して考えられる置換基は、原則としてこの目的のために当業者が考えることができる置換基の全ての群である。これらは、特にアミン基、ニトロ基、ヒドロキシル基、ハロゲン化物基、酸基、例えばカルボン酸、スルホン酸及びホスホン酸から成る群から選択された置換基である。これは、相当する塩、特にアルカリ金属又はアルカリ土類金属のカチオンを含む塩にも同様にあてはまる。 As sulfonic acid, general formula (II)

[Wherein, R represents substituted or unsubstituted (C ₁ -C ₈ ) alkyl, (C ₃ -C ₆ ) cycloalkyl, (C ₇ -C ₁₉ ) alkylaryl, (C ₆ -C ₁₈ ) aryl, ( C ₇ -C _{19) aralkyl, (C} 3 ~C _{18) heteroaryl, (C} 4 ~C _{19) alkylheteroaryl, (C} 4 ~C ₁₉₎ sulfonic acid or salt thereof hetero aralkyl alkyl] It is also advantageous to use The possible substituents for R and R ′ are in principle all groups of substituents that can be considered by the person skilled in the art for this purpose. These are in particular substituents selected from the group consisting of amine groups, nitro groups, hydroxyl groups, halide groups, acid groups such as carboxylic acids, sulfonic acids and phosphonic acids. This applies equally to the corresponding salts, in particular salts containing alkali metal or alkaline earth metal cations.

  Preferred compounds are 3-mercapto-1-propanesulfonic acid Na salt, 3- (2-benzothiazolyl-2-mercapto) propanesulfonic acid Na salt, saccharin-N-propylsulfonate Na salt, 3-sulfopropyl N, N- It is selected from the group consisting of dimethyldithiocarbamate Na salt, 1-propanesulfonic acid and 3-[(ethoxythioxomethyl) thio] K salt.

  In this connection, very particularly preferred are the disulfide compounds required for whitening systems, in which the sulfonic acid is in this case in one compound, for example with respect to bis- (3-sodium sulfopropyl) disulfide. Provided in.

  For example, it is possible to use citric acid as carboxylic acid (Jordan, Manfred, Die galvanische Abscheidung von Zinn und Zinnlegierungen, Saulgau 1993, p. 156). The betaines to be used can preferably be found in W02004 / 005528 or Jordan, Manfred (Die galvanische Abscheidung von Zinn und Zinnlegierungen, Saulgau 1993, p. 156). Particularly preferably, these are those present in EP636713. Other additives can be found in the literature (Jordan, Manfred, Die galvanische Abscheidung von Zinn und Zinnlegierungen, Saulgau 1993).

Another complexing ligand that can be used advantageously is pyrophosphate ion. These can be present in the electrolyte and can be advantageously introduced into the electrolyte as anions of metal salts to be deposited. However, embodiments in which pyrophosphate ions are added in the form of other metal salts, in particular in the form of alkali metals and alkaline earth metals, are also possible. The amount of pyrophosphate ions can be precisely adjusted by those skilled in the art. This is limited by the fact that the concentration in the electrolyte should be above the minimum amount that can still produce the effect in a sufficient range. On the other hand, the amount of pyrophosphate to be used is derived from an economic point of view. In this context, reference can be made to EP 1146148 and the corresponding information present therein. The amount of pyrophosphate to be used in the electrolyte is preferably 1 to 400 g / l. Particularly preferably, it is used in an amount of 2 to 200 g / l with respect to 1 l of the electrolytic solution. If pyrophosphate is not introduced as a salt component of the metal to be deposited, as described above, alkali metal or alkaline earth as sodium diphosphate or potassium diphosphate or H ₂ P ₂ O ₇ is used. It can be used in combination with a base of a similar metal. Preferably K ₂ P ₂ O ₇ is used for this purpose.

The electrolyte of the present invention does not contain hazardous substances classified as toxic (T) or extremely toxic (T ⁺ ). There are no cyanides, thiourea derivatives or equivalent toxic substances. The non-toxic electrolytes according to the invention are particularly suitable for the electrochemical application of decorative bronze layers to consumer goods and industrial products. It can be used in barrel, rack, belt or reel to reel type electroplating plants.

In a corresponding method for the electrochemical application of a decorative bronze alloy layer, the consumer goods and industrial products to be coated (hereinafter collectively referred to as support) are incorporated into the non-toxic electrolyte of the present invention. Soaked and forms the cathode. The electrolytic solution is preferably maintained in the range of 20 to 70 ° C. It is possible to adjust the current density in the range of 0.01 to 100 A / dm ² and depending on the type of plating plant. In a barrel plating plant, a current density in the range of 0.05 to 0.75 A / dm ² is preferred, more preferably 0.1 to 0.5 A / dm ² and particularly preferably about 0.3 A / dm ² . It is. In the rack plating method, a current density in the range of 0.2-10.0 A / dm ² is preferably selected, particularly preferably 0.2-5.0 A / dm ² and very particularly preferably 0.25-1. 0 A / dm ² .

  When using the non-toxic electrolytic solution of the present invention, various anodes can be used. Soluble or insoluble anodes are suitable, as well as combinations of soluble and insoluble anodes.

  As the soluble anode, an anode made of a material selected from the group consisting of electrolytic copper, phosphorous copper, tin, tin-copper alloy, zinc-copper alloy and zinc-tin alloy is preferably used. Particularly preferred are combinations of various soluble anodes made of these materials, and further a combination of a soluble tin anode and an insoluble anode.

  The use of an anode made of a material selected from the group consisting of platinum titanium, graphite, indium-transition metal mixed oxides and special carbon materials (“diamond-like carbon” DLC) or combinations of these anodes as the insoluble anode. preferable. Particularly preferred is a mixed oxide anode made of indium-ruthenium mixed oxide, indium-ruthenium-titanium mixed oxide, or indium-titanium mixed oxide.

The use of an insoluble anode is a particularly preferred embodiment of the process when the support is provided with a decorative bronze exhibiting a cathode, separated from the insoluble anode by an ion exchange membrane, thereby A cathode region and an anode region are formed. In such cases, only the cathode region is filled with the non-toxic electrolyte of the present invention. An aqueous solution containing only conductive salts is preferably present in the anode region. Such an arrangement prevents anodic oxidation from tin (II) ions Sn ²⁺ to tin (IV) ions Sn ⁴⁺ which adversely affects the plating process.

In the membrane process operated with an insoluble anode and the non-toxic electrolyte of the present invention, a current density in the range of 0.05-2 A / dm ² is preferably adjusted. The electrolytic solution is preferably maintained in the range of 20 to 70 ° C. It is also possible to use a cation or anion exchange membrane as the ion exchange membrane. Preferably, a membrane made of Nafion having a thickness of 50-200 / μm is used.

  Disadvantages of additive-free phosphate-based copper-tin electrolytes are limited to a narrow current density and lack of gloss and low brightness of the deposited layer. The new brightener system avoids these disadvantages in phosphate-based electrolyte systems. When only the electrolyte of the present invention is used, the bright and glossy layer can be deposited over a wide current density range. None of the known cyanide-free alternative methods (pyrophosphates, phosphonates, alkylsulfonates) achieved the properties of cyanide-containing baths (especially the gloss and lightness were only slight). Absent). The use of the brightener combination according to the invention makes it possible to achieve a gloss and brightness comparable to conventional cyanide-containing electrolytes, and thereby significantly more than all known cyanide-free alternative methods. It is good.

  Furthermore, the management of the bath is simpler with the electrolyte of the present invention. The new whitening system makes it possible to use electrolytes with a high copper content. The combination of compounds used, in particular the combination of brighteners containing carbonate ions and disulfide compounds, is important here. Even in very small amounts of organic disulfide compounds in the presence of carbonate ions, copper-tin alloy formation is affected. In contrast to the additive-free bath, a large and constant alloy composition is obtained over a wider range of current densities with the addition of the brightener system (FIG. 1—with or including the brightener). No copper-tin electrolyte composition based on phosphonic acid). In the case of an additive-free bath, the tin preferably deposits at a high current density, which leads to a lack of gloss in the layer.

For the purposes of the present invention, (C ₁ -C ₈ ) -alkyl is an alkyl group having 1 to 8 carbon atoms. This may be branched if preferred or it may be cyclic in the case of (C ₃ -C ₆ ) -cycloalkyl. This is especially methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl, pentyl, hexyl, cyclopropyl, cyclopentyl, cyclohexyl and the like.

(C ₆ -C ₁₈ ) aryl is aromatic based on a total of 6 to 18 carbon atoms. This is especially selected from the group consisting of phenyl, naphthyl, anthracenyl and the like.

(C ₇ -C ₁₉ ) -Alkylaryl is a group having a (C ₁ -C ₈ ) alkyl group on a (C ₆ -C ₁₈ ) aryl group.

The (C ₇ -C ₁₉ ) -aralkyl group is a group having a (C ₆ -C ₁₈ ) -aryl group on the (C ₁ -C ₈ ) alkyl group, and through the alkyl group, the group is It is associated with related molecules.

According to the invention, a (C ₃ -C ₁₈ ) -heteroaryl group is an aromatic system having at least 3 carbon atoms. In addition, other heteroatoms are present in the aromatic system. These are preferably nitrogen and / or sulfur. Such heteroaromatics are described, for example, in Bayer-Walter, Lehrbuch der Organischen 10 Chemie, S. Hirzel Verlag, 22nd edition, page 703 et seq.

For purposes of the present invention, (C ₄ -C ₁₉ ) alkylheteroaryl is a (C ₃ -C ₁₈ ) heteroaryl group appended with a (C ₁ -C ₈ ) alkyl substituent. The bond to the relevant molecule is here via a heteroaromatic.

Conversely, (C ₄ -C ₁₉ ) heteroaralkyl is a (C ₃ -C ₁₈ ) heteroaryl attached to the associated molecule through a (C ₁ -C ₈ ) -alkyl substituent.

  For the purposes of the present invention, halide includes chloride, bromide and fluoride.

  The following examples and comparative examples illustrate the invention.

  Alkyl (hetero) aryl is alkylaryl and alkylheteroaryl.

The graph which shows the comparison of the lightness value of the electrolyte solution by this invention, and the electrolyte solution by a prior art

Example:
Comparison of lightness values of phosphonate electrolyte containing brightener system and phosphonate electrolyte not containing brightener system (unit of L by Cie-Lab method [http://www.cielab.de])

  The formation of dark stripes was significantly suppressed. Furthermore, the layer quality was maintained even in the case of thick deposited layers.

  An insoluble platinum-titanium anode was used in all the tests described.

Example 1 General Method Barrel deposition of a white bronze layer was performed as 100 g / l ethylenediaminetetra (methylenephosphonic acid) EDTMP, 1.5 g / l copper as hydroxide copper carbonate, 5 g / l tin pyrophosphate. Of tin, 2 g / l zinc as zinc pyrophosphate, 10 m / l methanesulfonic acid (70%), 20 g / l potassium bicarbonate and 10 mg / l bis (3-sodium sulfopropyl) disulfide This was carried out using a non-toxic electrolyte solution according to the present invention.

During the entire deposition process, the electrolyte was maintained at 50 ° C. At a set current density of 0.05-0.5 A / dm ² , a visually uniform high gloss bronze layer with a typical color of white bronze was obtained in a drum plating apparatus.

Example 2:
80 g / l HEDP
50 ml / l methanesulfonic acid (70%)
10 g / l potassium carbonate 30 mg / l 2,2′-dithiodipyridine 1.47 g / l copper pyrophosphate 10.2 g / l tin pyrophosphate 2.5 g / l zinc pyrophosphate Parameters: pH 8.0 / 40 ° C./Current density: 0.05 to 0.5 A / dm ² .

Example 3:
200 g / l HEMPA
5 ml / l propanesulfonic acid 2 g / l potassium bicarbonate 25 mg / l 2,2′-dithiodipyridine 1.47 g / l copper pyrophosphate 10.2 g / l tin pyrophosphate 1.5 g / l Citric acid parameter of zinc pyrophosphate 10 g / l: pH 11.0 / 25 ° C./Current density: 0.05 to 0.5 A / dm ² .

Example 4
50 g / l ATMP
10 g / l potassium pyrophosphate 20 g / l citric acid 4.2 g / l hydroxide copper carbonate 8.66 g / l tin pyrophosphate 4.5 g / l zinc pyrophosphate 10 g / l potassium hydrogen carbonate 0 0.5 g / l 6,6′-dithiodinicotinic acid Parameter: pH 9.0 / 60 ° C./Current density: 0.05-0.5 A / dm ² .

Example 5: Yellow bronze:
150 g / l EDTMP
10 ml / l methanesulfonic acid (70%)
20 g / l potassium carbonate 9 g / l hydroxide copper carbonate 8.66 g / l tin pyrophosphate 5.5 g / l zinc pyrophosphate 15 mg / l bis (3-sodiumsulfopropyl) disulfide Parameters: pH 10 / 60 ° C./Current density: 0.05 to 0.5 A / dm ² .

Claims (15)

  In a non-toxic electrolyte solution for depositing decorative bronze alloy layers on consumer goods and industrial products, containing the metal to be deposited in the form of a water-soluble salt, the electrolyte solution is one or more of the complexing agents or The non-toxic electrolyte solution comprising a brightener comprising a phosphonic acid derivative and a disulfide compound and a carbonate or hydrogencarbonate.   The electrolytic solution according to claim 1 containing copper and tin or copper, tin and zinc metal ions to be deposited.   Water-soluble salts of metals to be deposited are pyrophosphate, carbonate, hydroxide-carbonate, bicarbonate, sulfide, sulfate, phosphate, nitrite, nitrate, halide, hydroxide 3. The electrolyte solution of claim 2, selected from the group consisting of: an oxide-hydroxide, an oxide, and combinations thereof.   The metal to be deposited is present in dissolved form, wherein the copper ion concentration is 0.2 to 10 g per liter of electrolyte solution, and the tin ion concentration is 1.0 to 30 g per liter of electrolyte solution, 4. The electrolytic solution according to claim 1, wherein if present, the ion concentration of zinc is 1.0 to 20 g per liter of the electrolytic solution. 5.   2. The electrolyte solution according to claim 1, comprising a salt of this type selected from the group consisting of alkali metal salts and alkaline earth metal salts as carbonates or bicarbonates.   6. Electrolyte solution according to claim 5, wherein carbonate ions or hydrogen carbonate ions are present in an amount of 0.5 to 100 g / l per liter electrolyte solution.   2. The electrolyte of claim 1 comprising a disulfide compound of this type selected from the group consisting of substituted and unsubstituted bisalkyl or bis (hetero) aryl or alkyl (hetero) aryl disulfides.   The electrolyte solution according to claim 7, wherein the disulfide compound is present in the electrolyte solution in an amount of 0.01 mg / l to 10.0 g / l.   As phosphonic acid derivatives, 1-aminomethylphosphonic acid AMP, aminotris (methylenephosphonic acid) ATMP, 1-aminoethylphosphonic acid AEP, 1-aminopropylphosphonic acid APP, (1-acetylamino-2,2,2-trichloro Ethyl) phosphonic acid, (1-amino-1-phosphonooctyl) phosphonic acid, (1-benzoylamino-2,2,2-trichloroethyl) phosphonic acid, (1-benzoylamino-2,2-dichlorovinyl) Phosphonic acid, (4-chlorophenylhydroxymethyl) phosphonic acid, diethylenetriaminepenta (methylenephosphonic acid) DTPMP, ethylenediaminetetra (methylenephosphonic acid) EDTMP, 1-hydroxyethane (1,1-diphosphonic acid) HEDP, hydroxyethylamino Di (methylene Sphonic acid) HEMPA, hexamethylenediaminetetra (methylphosphonic acid) HDTMP, ((hydroxymethylphosphonomethylamino) methyl) phosphonic acid, nitrilotris (methylenephosphonic acid) NTMP, 2,2,2-trichloro-1- (furan 2-carbonyl) amino-ethylphosphonic acid, salts derived therefrom and condensates derived therefrom or one or more compounds selected from the group consisting of combinations thereof Electrolyte of description.   The electrolytic solution according to any one of claims 1 to 9, wherein the pH of the electrolytic solution is in the range of 6 to 14.   The electrolytic solution according to any one of claims 1 to 10, wherein pyrophosphate ions are present in the electrolytic solution.   12. One or more stabilizing compounds selected from the group consisting of monocarboxylic and dicarboxylic acids, alkanesulfonic acids, betaines and aromatic nitro compounds, according to any one of claims 1 to 11. Electrolyte of description.   In the electrochemical application method of decorative bronze alloy layers to consumer goods and industrial products, the support to be coated is immersed in an electrolyte containing the metal to be deposited in the form of a water-soluble salt. The said method using the nontoxic electrolyte solution of any one of Claim 1-12.   The method according to claim 13, wherein the electrolyte is maintained in the range of 20 to 70 ° C. during metal deposition. The method according to claim 13, wherein the current density is adjusted to a range of 0.01 to 100 A / dm ² .

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