DE4405423C2 - Mono-noble metal dithiolates, process for their preparation and their use - Google Patents

Description

The invention is directed to mono-noble metal dithiolates, in particular water-soluble monogold (I) dithiolates, whose Production and use for manufacturing precious metal-containing decors, in particular high-gloss Decors made of a coherent precious metal film, on burnable documents. It will continue a precious metal containing preparation for Decorating burnable documents described that at least one Mono-noble metal dithiolate according to the invention, an or several organic polymeric binders and solvents contains.

For the production of a precious metal decoration, in particular one essentially gold and / or silver in the form of a high-gloss metal film trained decor, among which also tracks made of especially gold in integrated Count circuits on a stovable substrate find for a long time so-called precious metal preparations, for example, bright gold preparations and polished gold preparations, Application. Such preparations generally contain one or more, in a purely organic or organic aqueous carrier medium soluble organic sulfur Precious metal compounds, so-called noble metal thiolates, wherein the noble metal in the case of Ag and Au in the monovalent oxidation state is present. The mentioned Preparations contain except the precious metal compound, the Solvent and one or more organic polymers Binders additionally one or more fluxes, such as for example so-called resinates and / or simple salts, Oxides or coordination compounds of one or more  the elements boron, silicon, vanadium, chromium, indium, zinc, Antimony, bismuth and rhodium. The precious metal preparations are using common direct and indirect printing methods, Spraying or brushing or using the Decal technique on the surface to be coated applied. After evaporation of the solvent closes a firing at a on the substrate and the Gold preparation tuned temperature - usually lies the maximum firing temperature between 400 and 900 ° C, However, in special cases, higher temperatures possible. The burning process becomes a precious metal film formed and fixed on the surface of the substrate. It is well known to the art that to obtain high-gloss precious metal films the precious metal used thiolate, the binder and the solvent system must be carefully coordinated to brilliant and adherent to the substrate decorating films, among which also tracks for be understood electrical / electronic purposes, too come.

In the organic sulfur compounds for the mentioned Decoration preparations, it was almost a long time exclusively to so-called Goldsulforesinate, which from a gold salt and sulfurized, especially natural occurring terpenes were recovered. In new time have synthetically produced noble metal thiolates, in particular Gold (I) thiolates of the general formula Au-S-R in importance won; R is here in particular an alkyl, Cycloalkyl, aryl or aralkyl group or a bicyclic hydrocarbon radical. The mentioned gold (I) - thiolates generally required the use of a purely organic solvent system - exemplified refer to EP-B 04 91 143.

For occupational hygiene, safety and environmental reasons There is a growing interest in precious metal preparations  for decorating stovable substrates in whose Solvent system at least part of the organic Solvent is replaced by water. So is out of the DE-OS 32 17 049 a paint for applying a Overglaze decoration on porcelain known, the 15 to 40 Wt .-% polyvinylpyrrolidone or a mixture of Polyvinylpyrrolidone and aqueous polyethylene oxide, 45-85 Wt .-% ethylene glycol and / or propylene glycol and possibly Contains water. As coloring substances are used in this Document oxides, gold and organic gold compounds but without any structure of the Indicate gold compounds.

A polyvinylpyrrolidone and water-containing Polished gold preparation, the binder as an additional aqueous acrylate resin dispersion and as a coloring component Gold powder and / or a poorly soluble gold compound is known from GB-A 22 16 536. evidenced The examples are always in these preparations alcoholic solvents present. precious metal preparations on the basis of the aforementioned documents, such as the Practice showed, often to decors, which one have insufficient gloss.

From EP-A 05 14 073 are homogeneous compositions, preferably solutions known, which during baking form a shiny metallic precious metal film. The Compositions contain from 3 to 22% by weight of one Noble metal thiolate, a polymeric resin and as Solvent system a mixture of water and a organic solvent (cosolvent) in which it is preferably water-miscible alcohols, ethers or esters is. Both the precious metal thiolate and the Binders should be soluble in the water / cosolvent mixture his. In the preferred used gold (I) thiolates these are those of the general formula Au-S-R-H or Au-S-R-X, where X is a nitro group or -COOH,  -SO₂OH, -OH, -CONH₂, -NH₂ or -O-P (O) (OH) ₂, wherein the H atoms may optionally be substituted, or salts and R is a divalent organic radical. From the document mentioned goes on the basis of numerous Examples and Comparative Examples clearly show that only very special gold (I) thiolates in corresponding Gold preparations to decors with good gloss and good Adhere to the adhesive on the decorated surface.

Proven as described in this document Comparative examples could be made using some of the aforementioned formulas of falling gold (I) thiolates, including, for example, gold (I) -mercaptosuccinic acid only dull-looking decors can be obtained.

Object of the present invention is accordingly, a to disclose another group of noble metal thiolates which for the production of high-gloss precious metal decors suitable for firing. The questionable Precious metal thiolates should have their effect in particular Unfold water-containing bright precious metal preparations.

It has surprisingly been found that by the Introduction of a second sulfhydryl group in the Noble metal thiolate underlying organic compound the suitability of the precious metal thiolate as an ingredient of Precious metal decorative preparations for the production high-gloss precious metal decorations could be significantly improved.

The subject of the present invention accordingly Mono-noble metal dithiolate of the general formula (A)

in which mean
Em: a noble metal from the series Au (I) or Ag (I) or one equivalent of Pd (II), Pt (II) or Rh (III)
Q: a tetravalent organic radical having 2 to 10 C atoms, which may additionally contain oxygen, nitrogen or sulfur atoms in the form of hydroxyl, carboxyl, alkoxy, amino, alkylamino, mercapto or alkylmercapto, or a 5- or 6-membered cycloaliphatic tetrayl radical which may have an oxygen or imine ring member,
Y: a hydrophilic group from the series -COOH, -COO⁻Kat⁺, where Kat⁺ for Li⁺, Na⁺, K⁺, NH₄⁺, (C₁-C₃-alkyl) _n N⁺H _(4-n) or (hydroxy (C₁ to C₃) alkyl) _n N⁺H _(4-n) and n are an integer between 1 and 4, and
Z: equal to Y or -H.

Preferred mono-noble metal dithiolates are contained as noble metal Gold or silver, especially gold.

The tetravalent organic radical Q and the substituents Z and Y are preferably selected such that the resulting Mono-noble metal dithiolate a high solubility in water having. A good water solubility is especially then obtained when Y and / or Z COO⁻Kat⁺ mean.

If in the mono-noble metal dithiolates according to the invention Y and / or Z is -COO⁻Kat⁺, the said Ammonium cations are preferred over the alkali metal cations. In the case of the alkylammonium cations, alkyl may be methyl, ethyl, n-propyl or i-propyl; at the alkylammonium cations may be mono-, di-, tri- or tetra-alkylammonium with the aforementioned alkyl groups, which are also mixed can, act. For mono-, di-, tri- or tetra Hydroxyalkylammoniumkationen stands for the hydroxyalkyl group Hydroxymethyl, hydroxyethyl, 2-hydroxypropyl or 3-hydroxypropyl. Starting from Y and / or Z is carboxyl can be said salts in a simple manner by a usual neutralization reaction using the corresponding amine or ammonium hydroxide produce.  

As far as Y is the group -COO (CHR¹-CHR²-O) _m R³, m is preferably an integer between 3 and 7. Mono-noble metal dithiolates with Z equal to hydrogen naturally have a lower water solubility and thus a lower suitability for hydrous precious metal preparations as compounds in which Z itself represents a hydrophilic group.

The organic radical Q contains between 2 and 10 C atoms; The rest can additionally oxygen, nitrogen or Sulfur atoms in the form of hydroxyl, carboxyl, alkoxy, Amino, alkylamino, mercapto or alkylmercapto groups contain. It is particularly preferred that organic radical Q to a C₂-, C₃- or C₄- Alkantetraylrest. According to another embodiment the organic radical Q is a 5- or 6-membered one cycloaliphatic tetrayl radical, wherein a C-ring member by Oxygen (-O-) or an imino group (-NH- or -NR-) can be replaced; the cyclic radicals Q are thus cyclohexanetetrayl, cyclopentanetetrayl, Tetrahydrofurantetrayl, pyrrolidine tetrayl, piperidine tetrayl or tetrahydropyrantra-tetrayl.

In the mono-noble metal dithiolates according to the invention can the SH group and SEm group adjacent to each other Carbon atoms or by one or more members be bound to each other separated carbon atoms. Compounds in which the SH and SEm groups are attached adjacent carbon atoms are especially prefers. Accordingly, mono-noble metal dithiolates, in particular monogold (I) and monosilver (I) dithiolates of  Dimercaptosuccinic acid and its salts with the cation Kat⁺ particularly preferred. As already mentioned, it is particularly useful, a salt from the mono precious metal dimercaptosuccinic acid with a mono-, di- or tri- (C₁- to C₃-) alkylamine or mono-, di- or tri (hydroxy- (C₁-) to form C₃-) alkyl) amine. For salt formation is an amine from the series mono-, di- or triethanolamine as well Triethyl-, tri-n- or tri-iso-propylamine in a zur Neutralization of the carboxyl groups present sufficient Amount especially suitable.

Mono-noble metal dithiolates with the previously indicated Structure have never been described before, and therefore not for use in making metallic precious metal-containing decors on stovable substrates been proposed. Due to the property comparison of decors, which on the one hand with inventive Mono-noble metal dithiolates and on the other hand with previously known structurally similar noble metal thiolates, which have no additional SH group produced, It is assumed that the mono-noble metal according to the invention thiolate through the additional SH group such be stabilized that during the baking process of the on a stovable surface, such as glass, porcelain and Ceramic, applied precious metal compound coherent, adherent and glossy Precious metal film can be formed.

The preparation of the mono-precious metal according to the invention dithiolates of the general formula (A ')

wherein Q, Y and Z have the abovementioned meaning takes place in a fundamentally analogous way, as is the case from the production Prior art noble metal thiolates known in the art -  see the documents cited above. In case of Monogold (I) dithiolate is recovered from tetrachloroauric acid Addition of the double equivalent amount of a thioether R''SR '' 'a gold (I) complex of the formula AuCl (R''SR' '') educated; the said complex is then in the presence a solvent having a substantially equivalent Molar amount of a dithiol (dimercapto compound) of general formula (B) implemented

where Q, Y and Z again have the same meaning as in the formula (A '). A particularly useful thioether for the formation of the gold (I) complex is methionine.

The preparation of the dithiol compound (B) is carried out under Use of common process steps: for example Dimercaptoalkandicarbonsäuren can be converted the corresponding alkynedicarboxylic acids with thioacetic acid win; another accessibility for aliphatic and cyclic dimercapto compounds of the general Structure (B) also consists of the corresponding one Dihalogen compound (Z-Q (Hal) ₂-Y) with an alkali metal sulfide implement. Inventive Ag compounds can be in easy way by reacting a soluble Ag salt win with a dithiol (B). In a similar way are Pd and Pt compounds of the invention from a Pd (II) - or Pt (II) salt and the dithiol, here at a molar ratio of about 1 to 2.

The mono-noble metal dithiolates according to the invention can be obtained expediently in the form of precious metal-containing preparations for Decorating stovable substrates, in particular glass, Porcelain and ceramics, use. Such preparations contain at least one monoelmetal metal according to the invention dithiolate, one or more polymeric organic binders  and usually solvents, preferably an aqueous organic solvent system to include herein the organic To solve polymers as well as the mono-noble metal dithiolate or otherwise to ensure a homogeneous distribution. If necessary, contain the precious metal-containing In addition, supplements to the desired Processing properties, such as a screen-printable Viscosity and a high drying speed of the Preparation, and very specific optical - Color shades - and use properties, such as adhesion to the underground.

Aqueous preparations according to the invention contain such polymeric binders which are soluble in water or to form a clear dispersion therein. Useful binders are polyacrylic acid, polymethacrylic acid, Polyvinylpyrrolidone, cellulose ethers, in particular Carboxyalkyl and hydroxyalkyl cellulose, Polyalkylene glycol, polyvinyl acetate, polyvinyl alcohol, Polyamines, alkyd resins and polyurethane resins. The binders may be in the form of homopolymers or copolymers or Block polymers each individually or in the form of mixtures to apply. Especially preferred for preparations With high water content, polyvinylpyrrolidone homo- or copolymers, polymethacrylic acid homopolymers or copolymers and resins based on cellulose ethers.

In the case of gilding preparations, in particular Bright gold preparations and polished gold preparations these for color control a small amount of one or a plurality of others substantially soluble in the system Precious metal compounds in the form of resinates or Sulforesinaten or in the form of simple noble metal salts or complexes. In addition, the preparations usually contain Fluxes in the form of compounds, for example Resinates, salts, oxides or coordination compounds, one or more of the elements boron, silicon, vanadium,  Chromium, indium, tin, antimony, bismuth and rhodium. preparations containing an aqueous-organic binder system as organic solvent one or more water-soluble organic solvents, in particular water-soluble alcohols, ethers and esters. Especially glycols having 2 to 4 C atoms and oligo- and poly (C₂ to C₄) glycols or mono (C₁ to bis) C₄-) alkyl ethers of said glycols or oligoglycols, further (C₂ to C₅) hydroxycarboxylic acids or lower Alkyl esters thereof, in particular C₁ to C₃- Alkyllactate, use.

Further excipients in the preparations according to the invention may be common substances for altering the rheological Properties of the preparation, surfactants, the Adhesive reinforcing auxiliaries as well Drying accelerator in the case of using a UV-curable resin. The additional use of a aqueous polysulfide solution has in some cases especially in polyvinylpyrrolidone-containing Preparations proved to be expedient.

In the case of so-called shiny gold preparations included this is a monogold (I) dithiolate in an amount of 2 to 25 Wt .-%, preferably 5 to 15 wt .-%, each calculated as Gold. The binder content in the preparations is in general between 3 and 45 wt .-%, wherein the Weight ratio of resin to noble metal preferably is between 0.5 to 1 to 1.5 to 1. The water content is generally between 10 and 80% by weight, preferably between 30 to 60 wt .-%, and the content of organic solvent between 10 and 40% by weight, in each case based on the preparation. The amount of the Flux usually moves in the range between 0.01 and 2 wt .-%, based on the preparation. In case of so-called polished gold preparations contain these in addition Gold powder and / or finely divided insoluble  Gold compounds. Depending on the desired effect Polished gold preparations additionally glass frits and / or Organosilicon compounds included.

The mono-noble metal dithiolates according to the invention containing preparations can directly by means of conventional Decoration methods, such as spraying, brushing or known Printing process, in particular screen printing, to which applied decorating surface and after evaporation the solvent constituents decor at one Temperature between generally 400 and 900 ° C be burned. Alternatively, this can be Precious metal preparation according to the invention with concomitant use a decal on the object to be decorated transfer. The production of the decal takes place in for the expert known manner, wherein the Monogold (I) dithiolate compound according to the invention in the Decorative layer of the decal is located: On one on one Carrier applied water-soluble separating layer or a Thermal separating layer is made using a previously described noble metal-containing preparation and Evaporation of the solvent components and optionally crosslinking the binder a decorative layer applied; the decorative layer is usually over-coated.

The invention was a new class of materials for Provided, which is excellent for Production of film-like precious metal-containing decors suitable. The decors are surprisingly high glossy and Adhere perfectly to the substrate surface, as a coherent film is formed. By the Mono-noble metal dithiolates according to the invention is the Experts provided a new class of material, which not only in conventional precious metal preparations, which as solvent substantially only organic Solvents can be used, but rather, in such precious metal preparations, which a  aqueous-organic solvent system with high Contain water content. The production of new ones Precious metal compounds and their outstanding suitability in hydrous preparations for decoration Bakeable substrates follows from the examples. The Comparative examples show that using structurally similar compounds which are not second Mercapto group included, no satisfactory Precious metal decorations can be produced.

Example 1 Preparation of monogold dimercaptosuccinic acid

a) 0.035 mol = 18.49 g HAuCl₄ (37.29% Au) is under Stirring to a suspension of 0.07 moles of methionine in 70 ml of H₂O added dropwise. By external cooling is the Temperature maintained at 0 to 5 ° C. After completion the reaction turns the gold (I) complex into one Suspension of 0.035 mole = 6.38 g meso-2,3- Dimercaptosuccinic acid in 150 ml of dichloromethane dripped within one hour. The rainfall will sucked off, washed several times with water and in Desiccator dried under vacuum over blue gel. The Yield of Monogolddimercaptobernsteinsäure is 96.5%, based on the gold used.

13 _C-NMR in D₂O + trimethylamine δ / ppm 52.58 (CH), 60.95 (CH), 180.64 (CO₂ ^- ) and 182.51 (CO₂ ^- ).

b) Example 1a was repeated, but with instead of dichloromethane water was used. Also in  In this case, monogold (I) dimercaptosuccinic acid was used obtained in high yield and purity.

Comparative Example 1

Analogous to Comparative Example 7 in EP-A 05 14 073 the following components are mixed:

parts by weight Polymethacrylate resin (Versicol K11 from Allied Colloids)) 11 Goldmercaptobernsteinsäure 18 1,3-propanediol 15 water 40 isopropanol 15 Rhodium complex 0.04 chromium trioxide 0.05

The preparation is painted on porcelain and 10 min at 820 ° C heated, the heating time is one hour. You get a dull movie. Gloss measurements showed the following values:

The gloss measurements were made with the "haze-gloss" reflectometer performed by ByK Gardner. The preparation was on a porcelain plate 4 cm × 4 cm brushed and on measured in different places. Given is the Average of the individual measurements and the associated Standard deviation, as stated by the meter, as well as the angle under which the measurements are made were.  

Comparative Example 2

The following composition is analogous to Comparative Example 1 prepared:

parts by weight Polyvinylpyrrolidone (PVP K25 from Fluka) 8.1 Goldmercaptobernsteinsäure 17.2 1,2-propanediol 8.1 water 39.9 ethyl lactate 16.2 Rhodium complex 0.15 chromium sulfate 0.04 ammonium bismuth citrate 0.44 triethylamine 5.3 Ammonium polysulfide solution (15% in water) 1.9 Silbermercaptopropionylglycin 2.6

The preparation is painted on porcelain and 10 min at 820 ° C heated, the heating time is one hour.

You get a dull movie. Gloss measurements showed the following values:

example 2

In the following composition was different from the Comparative Example 2 only one of the invention Gold compound used according to Example 1:

parts by weight PVP K25 8.1 Monogolddimercaptobernsteinsäure 18.8 1,2-propanediol 8.1 water 38.3 ethyl lactate 16.2 Rhodium complex 0.15 chromium sulfate 0.04 ammonium bismuth citrate 0.44 triethylamine 5.3 Ammonium polysulphide solution (15%) 1.9 Silbermercaptopropionylglycin 2.6

The preparation is painted on porcelain and 10 min at 820 ° C heated, the heating time is one hour. You get a shiny, well-adhering film. Gloss measurements gave the following values:

example 3

The following ingredients were mixed:

parts by weight PVP K25 8.6 Monogolddimercaptobernsteinsäure 19.5 1,2-propanediol 8.6 water 34.3 ethyl lactate 17.3 Rhodium complex 0.16 chromium sulfate 0.07 ammonium bismuth citrate 0.53 triethylamine 5.7   Ammonium polysulphide solution (15%) 2.6 Monosilberdimercaptobernsteinsäure 2.6

The preparation is painted on the porcelain and 2 min at 880 ° C. heated, the heating time is 30 min. You get a shiny, well-adhering film.

Claims (4)

1. Mono-noble metal dithiolate of the general formula (A) in which mean
Em: a noble metal from the series Au (I) or Ag (I) or one equivalent of Pd (II), Pt (II) or Rh (III)
Q: a tetravalent organic radical having 2 to 10 C atoms, which may additionally contain oxygen, nitrogen or sulfur atoms in the form of hydroxyl, carboxyl, alkoxy, amino, alkylamino, mercapto or alkylmercapto, or a 5- or 6-membered cycloaliphatic tetrayl radical which may have an oxygen or imine ring member,
Y: a hydrophilic group from the series -COOH, -COO⁻Kat⁺, where Kat⁺ for Li⁺, Na⁺, K⁺, NH₄⁺, (C₁-C₃-alkyl) _n N⁺H _(4-n) or (hydroxy (C₁ to C₃) alkyl) _n N⁺H _(4-n) and n are an integer between 1 and 4, and
Z: equal to Y or -H. 2. Mono-noble metal dithiolate according to claim 1, characterized, that it is monogold (I) or monosilver (I) dimercaptosuccinic acid or a salt thereof the cation is Kat⁺ of the aforementioned meaning. 3. Process for the preparation of mono-noble metal dithiolates of the general formula (A ') wherein Q, Z and Y have the meaning of claim 1, by reacting an Au (I) complex of the formula AuCl.R''SR ''', wherein R''RR''' is a thioether, having a substantially equivalent molar amount of a thiol in the presence of a solvent, characterized in that the thiol is one of the general formula (B) wherein Q, Y and Z have the same meaning as in the formula (A ') used. 4. Use of the mono-noble metal dithiolates of the claims 1 to 2 for producing precious metal-containing decors and Tracks on burnable documents.