DE2025538A1 - Copper acid electrodeposition using brightener composition - Google Patents

Abstract

Metal and plastics, such as acrylonitrile-butadiene styrene graft copolymers are plated with ductile, bright, pore-free, adherent Cu from electroplating bths operated at 15-30 degrees C and 1-15 A/sq. dm. current density containing simultaneously added:(A) (a) cyclic or polymeric disulphide with C-S-S-C gps. containing at least one sulphonic or phosphonic acid group and opt. substd. by further water-solubilising gps. where polymeric disulphides contain several disulphide gps. and sulphonic or phosphonic acid groups; (B) an acid organic cpd. X-R2-Y (where X and Y are H, OH, SO3H, -PO(OH)I; R2 is 1-6C (iso)alkylidene or phenylene, and in which at least one sulphonic or phosphonic acid group and further water-solubilising gp(s) are present for 1-6C atoms) and (C) an aliphatic polyether with 6-150 ether O-atoms linked by 3-5 alkylidene gps. Pref. (A), (B) and (C) are combined to a brightener mixture which can be used for new batches or for regenerating exhausted electrolyte.

Description

Process for galvanic bright copper plating from acidic electrolytes The invention relates to methods for the galvanic deposition of high-gloss copper layers from acidic electrolytes.

Electrolytic copper plating is a very common process to refine the surfaces of metals and plastics and to increase corrosion resistance. The copper layer often forms a base for further galvanic treatment.

In practice, the quality of the copper layers obtained made high demands. In order to obtain perfectly flat and shiny surfaces, the berue is mechanically polished. However, this requires a number of individual operations, their costs in relation to the cost share for the electrolytic copper plating are relatively high. Therefore, attempts have been made for a long time to make copper shinier Separate form from acidic copper salt solutions.

A large number of processes have been described which work with grain-refining electrolyte additives such as glue, gelatin, dextrin, amino acids, aldehyde condensation products or polyhydric alcohols. Better results are achieved with organic compounds which, in addition to a water-solubilizing group, contain the atom groupings in the molecule contain and cause shine in certain current density ranges.

In particular, derivatives of thio and dithiocarbonic acid are used as gloss-forming agents Electrolyte additives known, e.g. thioureas, thiocarbamic acid esters, dithiocarbamic acid esters and derivatives of 2.4.6-trimercapto-1.3.5.-triazines (thiocyanuric acid derivatives). These Clancants have as a common characteristic an exclusively with heteroatoms linked carbon atom and water-solubilizing groups in the molecule. Farther are substituted thicamides and isothioamides of carboxylic acids, thioether sulfonates, Mercaptoalkanesulfonic acids and a number of derivatives of thiophosphoric acid as glanzbildcude means used.

The practical feasibility of galvanic bright copper plating depends on a large number of important factors, so that only a few of the numerous' described processes are technically feasible; e.g. Must @ n the received Bright copper layers be ductile.

Processes that work with brighteners, which the atom grouping # Contain C = S (e.g. thichureas etc.

Thickchlenic acid derivatives), deliver brittle or insufficient ductile Bright copper layers. O ur processes only deliver shiny copper coatings in one narrowly limited current density range, i.e. the surface quality of the copper layers is at the controller of high current density (on edges and corners of the workpieces) from flat surfaces deposited copper layer 8 6ark different. Further demands In practice, for example, good adhesive properties, absence of pores in the copper layers and, if possible, good leveling @es G @ undmaterials. Continuous operation may be caused by electrochemical changes of the electrolyte components, there is no reduction in gloss that is not due to the addition of @eu can be remedied by shine @ itteln. Further requirements in practice are insensitivity the electrolyte against small fluctuations in temperature, chloride concentration and stress. The brightener used should be effective in low concentrations and should only be consumed slowly.

These effects should be largely independent of type and intensity the movement of the electrolyte, e.g. by mechanical stirring, pumping over or by Blowing in compressed air can be done. For regeneration and growth of the acidic Bright copper electrolytes should be able to use the same means.

The state of the art, despite the presence of an extensive amount, is empirical The observation material obtained does not yet have any clear cause-effect relationships (e.g. for gloss formation, ductility, current density, gloss range, etc.). the state-of-the-art processes. therefore still have the shortcomings mentioned above mentioned various demands of the practical Electroplating insufficiently or only partially to be fulfilled.

The invention is based on the object of a method for galvanic To develop bright copper plating, which enables the deposition of high-gloss, ductile copper coatings on metals and plastics in a large current density range and an interference-free allows economic work over long periods of time. It should be pore-free, well-adhering Copper layers can be deposited, which a subsequent galvanic Allow deposition of other metals, regardless of the type of electrolyte movement.

According to the invention, a conventional copper base electrolyte at a temperature of 15-30 ° C. and currents of 1-15 A, dm2 is added at the same time for galvanic gloss coppering from acid electrolytes: A) a disulfide with the grouping which can be open-chain, cyclic or polymeric and contains at least one sulfonic or phosphonic acid group and can be substituted by other water-solubilizing groups, the polymeric disulfides containing the disulfide group and the sulfonic or phosphonic acid groups several times (general formulas A1 - A9) 1 B) an acidic organic compound of the general formula X - R2 - Y, in which:.

X and Y = -H, -OH, -SO3H, -PO (OH) 2, where X and Y are identical or different could be; R2 s linear or branched Alk @ lidenrest with 1 to 6 C-atoms or a phenylene radical; and in de @ on 1 to 6 carbon atoms at least one sulf @ n or phosphonic acid group and one or more broad @ e something @ redeemable groups @ nth @ lten @@@@@ @@ C) an aliphatic Polyäthe @ with 6 to 150 ether-O-atoms, whereby the the O-atoms connecting alkylidene radicals consist of 2 to 5 carbon atoms and I or different could be. (general formulas C1 - C3) The ones in the tables are particularly suitable A, B and a named compounds.

Contain the acidic organic compounds mentioned under 13) as strongly acidic groups for example -RSO3- or -PO (OH2) residues and as water-soluble making groups, for example - OH or - COOH or further -RSO3- or -PO (OH) 2 radicals, but are free from divalent sulfur functions.

The polyethers mentioned under C) can by copolymerization of Tetrahydrofuran and 1,2-glycols are obtained.

Also uniform polymers of ethylene oxide or propylene oxide or Copolymers of these compounds can be used, the terminal OH groups fully or partially esterified with phosphoric acid, sulfuric acid or boric acid or can be etherified with alkylsulfonic acid esters.

Show oxalkylation products of phenols or aminosulfoic acids also good effect.

The polyethers C preferably carry polar terminal groups such as - HSO3, - OSO3H, - PO (OH) 2, alkyl-C6H4-O- or HO3-S-C6H4-O-.

The additives mentioned under A to C can be added to the base electrolyte as a free acid as well as in the form of salts, such as alkali, ammonium, Copper or aluminum salts, or as salts of organic bases, such as guanidinium salts, be added.

Mixtures of different disulfides mentioned under A), Mixtures of various acidic organic compounds and mixtures mentioned under B) various aliphatic polyethers mentioned under C) are used.

The disulfide (A), the organic acid (ß) and the polyether (C) can can be combined to form a mixture of brighteners, which can be used to make new acidic Copper base electrolytes as well as the regeneration of exhausted ones Base electrolyte is added. A common acidic one is preferably used Copper electrolytes consisting of 150 - 240 g / l CuSO4 @ 5H2O, 40 - 80 g / l H2SO4 and 0.03 - 0.12 g / l HaCl, to which instead of: sulfuric acid also sulfamic acid, fluoroboric acid, Phosphoric acid, polyphosphoric acid or mixtures of these acids can be added. Aluminum salts, for example, can be added as grain refiners. The kind the movement of the electrolyte does not have a negative effect on the quality of the deposited Bright copper layers.

It was further found that this is sufficient for most cases large current density gloss range can still be expanded. if the electrolyte a small amount of an organic base containing 2 to 6 N atoms is added, of which at least 2 are arranged in the molecular plane, e.g. α-α-dipyridyl, α, α-dipyridyl, imidazoles or substituted guanidines; especially suitable the compounds in Table D. Such additives cause that even with deposition thick copper layers at points of highest current density (at corners and edges) even Deposition takes place.

Corresponding effects are also achieved if you use the electrolyte polymeric organic bases, especially the compounds in Table Bs. These compounds can be produced by polymerization of vinyl pyridines or by reaction of diamines or guanidines with epihalohydrins or by reaction of diepoxides can be obtained with diamines. Additions of aliphatic polyamidines also have an effect that way.

The compounds A - E can be added to the electrolyte in the following concentrations specified: A: 0.0005 - 0.5 g / l B: 0.0005 - 0.5 g / l C: 0.002 - 10 g / l D: 0.0003 - 0.040 g / l E: 0.0003 - 0.040 gXl The technical effects of the invention The method consists in maintaining the good physical properties of the matt copper, shiny copper layers deposited in a wide current density range can be, whereby an economical continuous operation is possible that rur A mixture of polishing agents is necessary for new cuts and regeneration. The secluded Copper @@ is characterized by high gloss, very good ductility, good adhesion and freedom from pores. Even with high current densities, thick layers can be uniform deposited regardless of the type of electrolyte movement.

Heavy metal impurities are anointed in high concentrations not harmful; for example, iron and zinc have amounts of 20 g / l no detrimental effect yet.

The high quality and uniformity of the bright copper layer is unnecessary mechanical repolishing, saved by considerable processing and material costs can be.

Special economic-technical effects result from that the Elektro @@ tzusatz can be used practically unchanged in various areas is e.g. B. for electroplating cyanidic copper-plated steel or nickel-plated steel Steel for coagulating shiny intermediate layers for subsequent electroplating (Vehicle industry, household appliance industry). precisely the saving of mechanical Polishing work is also the low cost of maintenance and detoxification of the electrolyte a particular advantage. Further fields of application of the method according to the invention are the bright copper plating of zinc die-casting and ABS plastics (acrylonitrile-butadiene-styrene graft polymers). In the electrotechnical industry, the process for producing printed Circuits and printed circuit boards are used advantageously. In the printing roll copper plating high-gloss, ductile deposits are achieved at high current densities that are not must be smoothed more and which can be etched more sharply outlines than matt copper layers.

The invention is to be explained in more detail by means of examples. Of the Base sectrolyte has the following composition: CuSO4 # 5H2O 220 g / l H2SO4 60 g / l NaCl 0.05 g / l Example 1: The base electrolyte is mixed with 0.02 g / l compound 1 (table A) Na salt 0.02 g / l compound 12 (table B) 0.5 g / l compound 27 (table C) Cyanidically pre-coppered sheet steel is used as the cathode. One electrolyzes at 20 - 30 ° C with 1 - 4 A / dm2 and receives a high-gloss, pore-free ductile Copper plating.

Example 2: The procedure is as described in Example 1 with the addition of 0.03 g / l compound 5 (Tab. A) Cu salt 0.03 g / l Compound 11 (Tab. B) K salt 1.0 g / l compound 31 (Tab. C) Example 3: The seduction is carried out as described in Example 1 with the addition of 0.01 g / l compound 2 (Tab. A) Cu salt 0.02 g / l compound 20 (Tab. B) Na salt 2.0 g / l compound 29 (Tab. C) Example 4: One moves as described in example 1 with the addition of 0.05 g / l compound 1 (Tab. A) Cu salt 0.04 g / l compound 11 (Tab. B) K salt 1.5 g / l compound 27 C'I'ab. C) 0.004 g / l Compound 38 (Tab. D) Example 5: The procedure is as described in Example 1, with a nickel-plated steel sheet as cathode, with the addition of 0.02 g / l compound 8 (table A) 0.02 g / l compound 23 (table B) 0.05 g / l compound 35 (table C) 0.02 g / l compound 31 (Tab. C) 0.005 g / l compound 43 (Tab. D) Example 6: The procedure is followed As described in Example 1, a cathode made of die-cast zinc, which is cyanidic was pre-coppered, and added 0.015 g / l compound to the base electrolyte 9 (Table A) Na salt 0.005 g / l compound 1 (Table A) Na salt 0.025 g / l compound 15 (table B) 2.0 g / l compound 29 (table C) 0.004 g / l compound 46 (table @) example 7: Proceed as described in Example 1 and add base electrolyte per liter a ready-made solution of 0.01 g / l compound 1 (Tab. A) Na salt 0.005 g / l compound 11 (table B) 0.01 g / l compound 16 (table B) 0.004 / l compound 35 (table C) 2.0 g / l compound 29 (Tab. C) to, Example 8: The procedure is as described in Example 1, however, uses chemically pre-coppered ABS plastic (acrylonitrile-butadiene-styrene polymer) as the cathode.

Example 9: The procedure is as described in Example 1, but with a base electrolyte, which additionally contains 10 g H3PO4 / l.

In the general formulas: R and R1 = -H, -CH3, -C2H5, where R and R1 can be identical or different; R2 = linear or branched alkylidene radical with 1 to 6 carbon atoms or a phenylene radical; R3 »-i, -CH3 @ R4 = linear or branched alkyl radical with 1 to 12 carbon atoms; z = -H, -OH, -SO3H, -PO (OH) 2, -SH, -COCH; X and Y = -H, -OH, -SO3H, -PO (OH) 2, where X and Y can be identical or different; Q1 and Q2 = -SO3H, -PO (OH) 2, -B (OH) 2, -C6H5, R4-C6H4-, MH2-R2-, HO3S-CH2-CH2-, HO3S-CH2-CH2-CH2-, HO3S-C6H4-, H n - the numbers 0, 1, 2, m S the numbers 4 -i = the numbers 2 - 12, j = the numbers 2 - A1 - A9 C1 - C3 C3 Q1-O- (CH2) 2- [O- (CH2) 2-] mO- (CH2) 2-Q-Q2 Table A 1) HO3S-CH2-CHOH-CH2-SS-CH2-CHOH-CH2-SO3H 2) HO3S-CH2-CHOH-CH2-SS-CH2-CH2-SO3H 3) HO3S-CH2-CHOH-CH2-SS-CH2-CH2-PO (OH) 2 Table B 11) HO3S-CH2-SO3H 12) HO3S-CH2-CH2-SO3H 13) HO-CH2-CH2-SO3H 14) HO-CII2-CH2 ~ PO (OH) 2 15) HO-CH2-CHOH-PO ( OH) 2 16) HO3SO-CH2-CH2-SO3H 17) HOOC-CH2-SO3H 18) CH3-CHOH-CH2-PO (OH) 2 19) HO-CH2-CHOH-CH2-SO3H 20) HO3S-CH2-CHOH -CH2-SO3H 22) HO3S-CH2-CHOH-CHOH-CH2-SO3H 23) HO3S-C6H4-SO4H (o, m, p) 24) (HO) 2OP-C6H4-SO3H (o, m, p) 25) (CH3) 2N -C6H4-SO3H (o, m, p) TABLE C 26) HO- (CH2) 4-O- (CH2) 2- [O- (CH2) 4) -O- (CH2) 2-] 3-O- CH2-CH2-OH 27) (HO3) -PO-CH2-CH2- (O-CH2-CH2-) 100O-CH2-CH2-OH 28) (HO) 3-PO-CH2-CH2- (O-CH2- CH2-) 150O-CH2-CH2-OP (CH) 3 29) HO-CH2-CH2- (O-CH2-CH2) 100-O-CH2-CH2-OH 30) tert. Octyl-C6H4-O-CH2-CH2- (O-CH2-CH2) 6-O-CH2-CH2-OH 33) HO3-S-C6H4-O-CH2-CH2- (O-CH2-CH2-) 10O-CH2-CH2-OH 34) HO3S-C6H4-N-CH2-CH2- (O-CH2-CH2) 20- CH2-CH2OH H Table D. Table E 46) NH2- (CH2) 6-N = CH- [NH- (CH2) 6-N = CH] 10-NH- (CH2) 6-N = CH-NH- (CH2) 6-NH2 KG 300 - 1000

Claims (7)

Claims: 1. A method for galvanic bright copper plating from acidic electrolytes, characterized in that a common copper base electrolyte at temperatures of 15-30 0C and currents of 1-15 A / dm2 are added simultaneously: A) a disulfide with the group which can be open-chain, cyclisoh or polymeric and contains at least one sulfonic or phosphonic acid group and can be substituted by further water-solubilizing groups, the polymeric disulfides containing the disulfide group and the sulfonic or phosphonic acid group several times; B) an acidic organic compound of the general formula X - R2 - in which: X and Y = -H, -OH, -SO3H, -PO (OH) 2, where X and Y can be identical or different; R2 w linear or branched alkylidene radical with 1 to 6 carbon atoms or a phenylene radical; and in which at least one sulfonic or phosphonic acid group and one or more further water-solubilizing groups are contained for 1 to 6 carbon atoms; C) an aliphatic polyether with 6 to 150 ether carbon atoms, where the alkylidene radicals connecting the O atoms consist of 2 to 5 carbon atoms and can be identical or different. 2. The method according to claim 1, characterized in that the below Acid compounds mentioned A to C as salts of inorganic or organic bases can be used. 3. The method according to claim 1 and 2, characterized in that mixtures various disulfides named under A), mixtures of various named under B) acidic organic compounds and mixtures of various aliphatic compounds mentioned under C) Polyethers are used. 4. The method according to claim 1 to 3 »characterized in that disulfide (A) organic compound (B) and polyether (C) combined to form a mixture of gloss agents that both for the new preparation of acidic bright copper electrolytes as well as for can be added to the regeneration of exhausted bright copper electrolytes. 5. The method according to claim 1 to 4, characterized in that the Electrolytes organic bases with 2 to 6 N atoms, of which at least 2 N atoms are arranged in the molecular plane, are added. 6. The method according to claim 1 to 5, characterized in that the Electrolytes, polymeric organic bases, preferably polyvinylpyridines, polyamidines or polybases made from diamines and diepoxides, from diamines and epihalohydrins or from guanidines and epihalohydrins can be added. 7. The method according to claim 1 to 6, characterized in that the Electrolytes sulfuric acid, sulfamic acid, fluoroboric acid, phosphoric acid, polyn oop!: Ors: iure or mixtures of these acids can be added. Report on the publications on the state of the art 1. Dettner, H.W. and Elze, J .: Handbuch der Galvanotechnik Carl Hauser Verlag Munich, 1964/66 2. Strauss, W .: "The chemistry of acidic bright copper baths" held at the Conference INTERFINIS @ 68, Hanover, 5, - 9.5.68 3. Gerlach, J .; Dear, H.W. and Pawlek, F .: "Possible uses of organic inhibitors for copper refining electrolysis" Metall 21 (1967) H. 11, pp. 1130 - 1135 4. Resch, H .: "Investigations on the action of organic compounds to the electrocrystallization of copper from sulfuric acid Electrolytes "Diss.-Arbei @ TU-Dresden, 1966