NO119204B - - Google Patents

Description

Process for the production of shiny galvanic metal coatings.

Patent No. 87,948 relates to a method for the production of highly shiny galvanic metal coatings, which is distinguished by the fact that galvanic baths

organic sulphonic acids or their salts, which contain a

exclusively with heteroatoms connected

carbon atom, which is above a sulfur atom

linked to a divalent aliphatic residue,

which carries the sulfonic acid group.

By further designing this method, the inventors have found that man

with advantage can also use such organic sulphonic acids resp. salts thereof, where it

exclusively with heteroatoms connected

carbon atom is connected to the divalent aliphatic residue bearing the sulfonic acid group over a nitrogen atom. These

compounds contain one of three heteroatoms surrounded by a carbon atom, of which

heteroatoms at least one is a sulfur atom.

The second heteroatom is by definition

a nitrogen atom, and the third can be a

sulphur, nitrogen or oxygen atom.

The carbon hydrogen residue to which the sulfonic acid group and that of three heteroatoms

surrounded carbon atom is bound, can be both aliphatic and cycloaliphatic or

aromatic nature. It may further contain

substituents or also be interrupted by heteroatoms or heteroatom groups.

The products which according to the invention are to be used as additives for galvanic baths are known in and of themselves or they can be produced in a simple way, for example by reacting suitable nitrogen- and sulfur-containing compounds with sultones.

Among the compounds which according to the invention are to be used as bath additives, there are essentially 3 groups: a) The third heteroatom is a nitrogen atom, e.g. after the ordinary

formula

Such connections are e.g. reaction products of 2-aminothiazoles with sultones, as a reaction product of 2-amino-4-methylthiazole or 2-amino-6-methylbenzthiazole with propanesultone or butanesultone, as well as thiourea-N-phenylsulfonic acids and their derivatives, e.g. thiourea-N-phenyl-4-sulfonic acid. b) The third heteroatom is a sulfur atom, e.g. according to the general formula: Such compounds are e.g. the reaction products of 2-mercapto-thiazole-S-alkyl ether with sultones, such as the reaction product of 2-mercaptobenzthiazole-S-methyl ether and propane sultone, further derivatives of dithiocarbamic acid-S-alkyl esters, which at the nitrogen carry an alkyl sulphonic acid group. The production of these substances, starting from primary amines, can take place by reaction with sultones to the corresponding amino sulfonic acids, which are then transferred to the dithiocarbamic acid salts by reaction with carbon disulfide in an alkaline medium. The latter are alkylated in a known manner, e.g. by reaction with dimethyl sulfate. Instead of the sultones, you can also use halogen-alkanesulfonic acids. The obtained dithiocarbamic acid derivatives correspond to the general formula: c) The third heteroatom is an oxygen atom, e.g. according to the general formula:

Such connections are e.g. the reaction products of 2-ocythiazoles with sultones.

For the method according to the invention, such organic sulphonic acids or salts thereof are suitable, which contain several sulfonic acid groups. For example, such compounds can be used which, next to the nitrogen-bonded alkylsulfonic acid residue, contain a further sulfur- or oxygen-bonded alkylsulfonic acid residue, as is the case with N-alkyl

-dithiocarbamic acid-N-S-bis-alkane-co-sulfonic acids of the general formula:

These sulfonic acids with a heterobonded C atom or their salts can be used for all types of galvanic metal coating, e.g. by galvanic pre-copper plating, nickel plating, pre-zinc plating, silver plating, or also by the production of galvanic cadmium, bronze or brass coating. They provide high gloss, clinging ductile metal coatings. They can be used alone or in conjunction with known gloss agents, smoothing agents, pore-preventing agents, wetting agents or conducting salts. They are used in concentrations between 0.1 and 20 g/l. In general- | normally galvanize at temperatures below 60° C and with current densities between 0.5 and 12 amp/dms. As the means are practically not consumed by the galvanic processes, the baths have a long life.

Example 1:

For an acidic copper sulphate bath, which per liter contains dissolved 60 g of sulfuric acid and 170 g of crystallized copper sulphate, you put per liter bath liquid 1 g dithiocarbamic acid-S-methyl ester-N-ethyl-N-butyl-co-sulphonic acid sodium with the formula

When pre-coppering cyan-alkaline pre-coppered tin, at a temperature and using a current density in the range of 1-10 amp/dm2, even on heavy profiles, a highly shiny and firm coating is obtained, which after rinsing does not need any further finishing.

Example 2:

To an acidic copper bath of the composition described in example 1, you put liter bath liquid 1 g dithiocarbamic acid-S-ethyl ester-N-butyl-N-propyl-oo-sulphonic acid sodium with the formula:

When pre-coppering under the conditions mentioned in example 1, a highly shiny and clinging coating is obtained which has good ductility.

Example 3:

In a nickel bath, as per liter contains 60 g nickel chloride, 220 g crystallized nickel sulfate and 35 g boric acid, 1-2 g/l dithiocarbamic acid-S-methyl ester-N-butyl-co-sulphonic acid sodium is dissolved with the formula:

A galvanic treatment carried out at room temperature gives, when current densities of 1-10 amp/dm2 are applied, a persistent and highly shiny coating, which does not require any post-treatment whatsoever.

Example 4: You galvanize sheet steel at room temperature and with a current density of 4-9 amp/dm2 using a zinc bath, which per liter contains 200 g of zinc sulphate, 1 g of glacial acetic acid and as a brightening agent 1 g of the sodium salt mentioned in example 2, a highly shiny zinc coating is obtained, while without the use of this brightening agent you only get a dull coating.

Example 5: To an acidic copper bath of the composition described in example 1, you put liter bath liquid 3 g 2-amino-5-methyl-thiazole-N-propane-co-sulphonic acid sodium with the formula:

By galvanic pre-coppering of cyan-potassium pre-coppered sheet steel, mari is obtained in this bath

using a current density of 2-8 amp/dma fixed cover which has a very beautiful gloss.

Example 6: To a nickel bath of the composition described in example 3, you put liter bath liquid 2 g of the sodium salt of thiourea-N-phenyl-4-sulfonic acid. When using a current density between 1-10 amp/dm2, the bath produces a highly shiny and clinging nickel coating.

Example 7: To a nickel bath of the composition described in example 3, one puts per liter bath liquid 1-2 g of the sodium salt of N-butyl-dithiocarbamic acid-N-S-bis-propane-to-sulfonic acid with the formula

If you galvanize with a current density between 1-10 amp/dms, you get a highly shiny, pore-free and clinging nickel coating.

Claims (2)

1. Procedure for the production of galvanic metal coatings with a high gloss and which adheres well to the substrate, characterized in that organic sulphonic acids with the general formula where G means an organic residue, which has a carbon atom connected exclusively with heteroatoms, which is connected via a nitrogen atom to a residue R-SOsH, are used as additives to the bath , and where R is a divalent aliphatic residue which can also be substituted or by salts of these sulphonic acids. 2. Method according to claim 1, characterized in that sulfonic acids are used or salts thereof which further contain alkyl sulphonic acid residues bound over sulfur or oxygen.