US3423296A

US3423296A - Nickel electrodepositing baths,process,and additive composition comprising levelling agent therefor

Info

Publication number: US3423296A
Application number: US492266A
Authority: US
Inventors: Jean Louis Levasseur
Original assignee: Enthone Inc
Current assignee: MacDermid Enthone Inc
Priority date: 1964-10-08
Filing date: 1965-10-01
Publication date: 1969-01-21
Anticipated expiration: 1986-01-21
Also published as: DE1228886C2; GB1099186A; SE306210B; NL6504673A; FR1418244A; BE662876A; IL23688A; DE1228886B

Description

United States Patent 90,780 ILLS. Cl. 204-49 lint. Cl. C23lo 5/08 16 Claims ABSTRACT OF THE DISCLOSURE Aqueous acidic nickel electrodepositing baths containing as levelling agent the condensation reaction product of naphtho-1,8-sultone with a heterocyclic aromatic compound containing at least one five-membered heterocyclic ring including at least one ring nitrogen atom and at least one labile hydrogen atom. Such reaction product is prepared by heating an aqueous liquid admixture of the napthosultone and the heterocyclic aromatic compound present in at least the stoichiometric amount under acid conditions to an elevated temperature below 65 C., maintaining the admixture at the elevated temperature below 65 C. until the naphthosultone dissolves in the aqueous liquid, then heating the resultant liquid solution to a reaction temperature above 65 C. but below 100 C., maintaining the solution at a reaction temperature above 65 C. but below 100 C. until the viscosity of the liquid solution increases appreciably and the solution is of a syrupy consistency, and cooling the thus treated solution to ambient temperature.

This invention relates to novel condensation reaction products of a naphthosultone and a heterocyclic aromatic compound containing one or more five-membered rings, and more especially to new and improved nickel electrodepositing baths containing such condensation reaction products as additives, novel compositions containing the condensation reaction products and especially well suited as levelling additives for the baths, an improvement in the method for electrodepositing nickel involving the use of the novel baths herein, and the novel condensation reaction products per se.

Compounds obtained by the reaction of 1,3- or 1,4- sultones, especially of 1,3-propanesultone and of 1,4- butanesultone, with heterocyclic tertiary amines of one or more six-membered aromatic rings are known additives for nickel electrodepositing baths. The application of such compositions for nickel electroplating is set forth in French Patent 1,143,382, granted Mar. 14, 1956. In addition to 1,3-propanesultone and 1,4-butanesultone, this patent also discloses as reactant sulfones such as tolylsultone and naphtho-l,8-sultone. As the heterocyclic tertiary amines of one or more six-membered rings as reactant, such patent discloses those containing a pyridine ring or a diazine ring, both six-membered aromatic ring compounds, with ultimately one or two benzene rings attached to the siX-membered heterocyclic ring and/or substituents thereof.

Such known compounds or compositions, notably the reaction product of pyridine or quinoline with propaneice sultone, impart a good levelling eifect on customary types of bright nickel plating baths, but their action diminishes rapidly and prematurely in the course of time and it is necessary to prematurely regenerate these compositions by prolonged heating of the electrolyte for several hours at 85 C. The necessity of such regeneration is recognized in French Patent 1,324,768, granted June 2, 1962. Further the addition of such compounds diminishes appreciably the throwing power of the electrolyte, which is inconvenient when nickel plating articles of complex shape.

One object of this invention is to provide new and improved nickel electrodepositing baths achieving a maxi mum levelling effect.

Another object is to provide new and improved nickel electroplating baths which are highly levelling without a significant reduction in the throwing power of the bath.

Another object is to provide new and improved nickel electroplating baths characterized by providing a prolonged good levelling effect without the requirement of periodic regeneration of the baths by heating or otherwise.

A further object is to provide novel condensation reaction products of a naphthosultone with a heterocyclic aromatic compound containing at least one five-membered ring including one or more ring nitrogen atoms and one or more labile, i.e., easily substitutable, hydrogen atoms.

A further object is to provide an improvement in the method for electrodepositing of nickel characterized by providing maximum levelling of the nickel being deposited.

Another object is to provide new compositions containing the novel condensation products herein, and which are eminently well suited for use as levelling additives for nickel electroplating baths.

Still a further object is to provide a novel method for the preparation of the condensation reaction products herein.

Additional objects and advantages will be readily ap parent as the invention is hereinafter described in detail.

In accordance with the present invention, it has been found that by the addition to the prior nickel electrodepositing baths of the bath-compatible condensation reaction product of a naphthosultone, for instance naphtho- 1,8-sultone, with a heterocyclic aromatic compound containing at least one five-membered ring including one or more ring nitrogen atoms and one or more labile, i.e., easily substitutable or replaceable, hydrogen atoms, nickel electrodepositing baths are obtained which are highly levelling and without a significant reduction in throwing power of the electrolyte. In addition, the compounds of the invention are stable in the baths, which eliminates the requirement for periodic treatment for regeneration which was necessary in the case of the heterocyclic hexagonal, i.e., six-membered ring, aromatic compounds of the prior art.

The novel condensation reaction products herein usually contain two or more labile hydrogen atoms. In those reaction products containing one labile hydrogen, one or more easily substitutable or replaceable atom or group, for example a bath-compatible, water-solubilizing cation, e. g., Na, K or NH are also linked in the reaction product molecule.

The prior nickel plating baths which are improved upon by the present invention contain water as solvent or continuous phase, and nickel ions in the form of the sulfate,

sulfamate or fiuoborate of nickel. In addition these acid baths usually contain chloride ions, for instance as nickel chloride, for anode corrosion; boric acid; one or more stabilizers such as for instance, saccharine, para-toluene sulfonamide, hexylammine and cyanuric acid; one or more brighteners, for instance an alcohol or an unsaturated aldehyde; and one or more wetting agents, for instance lauryl sulfate.

The naphthosultones undergo the condensation reaction with the heterocyclic aromatic compounds hereafter set forth containing one or more five-membered rings including one or more ring nitrogen atoms and one or more labile hydrogen atoms to form the new and valuable condensation reaction products, in a molar ratio within the range of about 1-4 moles of the naphthosultone per mole of such heterocyclic aromatic compound. Such heterocyclic aromatic compounds include, for example, an indolinine, e.g., indolinine per se, of the formula:

a fi-nitrosoindole of the formula:

wherein M is a bath-compatible, water-solubilizing cation, e.g., Na, K or NH; a phthalocyanine, e.g., phthalocyanine per se, of the formula:

Q? IL: NH N N go a dimethyl-1,5-imidazole, e.g., dimethyl-1,5-imidazole per se, of the formula:

and its substitution derivative, porphyrins; and a succinimide e.g. succinimide per se, of the formula:

All of such heterocyclic aromatic compounds are obtainable in commerce. Such heterocyclic aromatic compounds contain in addition to carbon, hydrogen and nitrogen, typically up to four five-membered heterocyclic rings of the character previously described herein, either as such or fused to six-member aromatic rings. The naphthosultones herein, preparable by the intramolecular condensation of the corresponding hydroxynaphthalene sulfonic acid, are also obtainable in commerce.

In place of the known brighteners, the novel condensation reaction product or products of naphthosultones and acetylenically-unsaturated glycols can be added to the bath as brightener. Such brighteners are disclosed and claimed in copending U.S. Patent application Ser. No. 500,462, entitled Nickel Electroplating Baths and Novel Condensation Reaction Products of Naphthosulfones and Acetylenically Unsaturated Glycols as Brighteners Therefor, filed Oct. 1, 1965.

The novel condensation reaction product herein is added to the bath either as such or when combined with an inert, i.e., non-reactive with the constituents of the bath, liquid solvent in an amount within the range from about 5-600 milligrams per liter.

The bath herein is preferably used with mechanical cathode rod agitation; a bath temperature between about 20 C. and about 70 C., more preferably between about 55 C. and about 70 C.; a pH of the bath between 3.0 and 5.5, more preferably about 5.0; and a current density between 2 and 15 amps./dm. the optimum being between 3 and 7 amps./dm. for a bath having a temperature of the order of 65 C.

When the novel condensation reaction product herein is utilized as a solution in an inert, i.e., non-reactive with respect the constituents of the plating bath, liquid solvent, the solvent can be water. However any inert liquid solvent which is compatible with the plating bath can be utilized. The proportions of the condensation reaction product in such additive agent composition can be varied over wide limits, and do not form a part of this invention. It will suffice to point out that with higher concentrations of the condensation reaction product, smaller quantities of such addition agent composition are required to be added to the bath to obtain the desired concentration of such product within the range from about 5-600 milligrams per liter, than when lower concentrations of the condensation reaction product are present in the additive agent composition.

In its broader aspects, the preparation process for preparing the condensation reaction products herein comprises reacting in an aqueous system under acid conditions and at a reaction temperature a naphthosultone, for instance a naphtho-1,8-sultone, with the heterocyclic aromatic compound containing one or more five-membered heterocyclic rings including one or more ring nitrogen atoms and one or more labile hydrogen atoms.

More specifically the preparation process involves heating an aqueous liquid admixture of the naphthosultone and such heterocyclic aromatic compound in amount which is at least that required to stoichiometrically react with the naphthosultone to form the condensation reaction product, at an acid pH, preferably a pH of about 354.0, to an elevated temperature below 65 C., preferably of the order of 50 C., and maintaining the admixture at such temperature below 65 C. until the naphthosultone dissolves in the aqueous liquid. The thusobtained liquid. solution is then heated to a reaction temperature above 65 C. but below 100 C., preferably of the order of C. and maintained at the reaction temperature within the range aforesaid until the solution thickens, i.e., its viscosity is increased appreciably, and becomes of syrupy consistency. The thus-obtained mixture or solution is then cooled, to ambient or room temperature, for instance by being permitted to cool down or by indirect heat exchange with a cooling fluid, e.g., cooling water.

For a better understanding of the invention, the following examples of nickel baths are given according to the Example No 1 2 3 4 5 6 7 NiSO -7HO 330 380 330 330 380 0 Ni suliamate 0 0 0 0 0 450 400 NiCl-(SHO 80 45 80 80 45 30 30 2B O 3 40 40 40 40 40 50 50 Saccharin. 0. 1 0. 0. 1 0. 2 0. 5 0. 2 0. 2 Paratoluen sulionanndeu 0. 1 0. 1 0. 1 0. 1 0. 1 0. 1 0. 1 Cyanuric acid 0. l 0 0. 1 0. 3 0 0. l 0. 1 Brlghtener A 0. 2 0. 2 0 0 0. 3 0. 2 0 Brlghtener 0 0 0. 2 0. 1 0 0 0. 2 Compound A- 0. 05 0 0 0 0. 04 0. 05 0 Compound B- 0 0.025 0 0 0 0.05 0 Compound C 0. 02 0 0 0. 05 0 0 0. 10 Compound D 0 0. 05 0 0. 025 0. 02 0 0 Compound E 0 0 0. 1 0. 05 0 0 0 Compound F... 0 0 0. 05 0 0 0 0 Compound G 0 0 0 0 0. 01 0 0 pH 4.0 3.5 4.5 4.0 4.0 3.5 3.5 Temperature 55-70 55-70 60 55-70 55-70 40-68 60 2-7 2-7 2. 7 2-7 2-7 15 Current density (amps/ Brightener A was butynediol.

Brightener B Was the product of the equimolar condensation reaction of bishydroxyethylether of the hutynediol with naphtlro-LS-sultone.

The Compounds A to G in the Examples of the preceding table are designated the following herein and are obtained by the condensation reaction of the reactants stated:

Compound A.Indolinine naphtha-1,8 sultone, resulting from the equirnolar reaction of indolinine and of naphtho-1,8 sultone. Optimum quantity of Compound A is 10-500 mg./1.

Compound B.Indole-B-isonitroso naphtho-l,8 sultone, resulting from the equimolar reaction of fl-nitroso indole and naphto-1,8 sultone. Optimum quantity of Compound B is 5-500 mg./l.

Compound C.-Phthalocyanine nap'htho-1,8 sultone, resulting from the reaction of one mole of phthalocyanine and four moles of naphtho-1,8 sultone. Optimum quantity of Compound C is 10-300 mg./l.

Compound D.-Dimethyl-1,5 imidazole naphtha-1,8 sultone, resulting from the equimolar reaction of dimethyl- 1,5 imidazole and naphtho-l,8 sultone. Optimum quantity of Compound D is -600 mg./l.

Compound E.-Porphine naphtho-1,8 sultone, resulting from the reaction of one mole of porphine and two moles of naphtho-1,8 sultone. Optimum quantity of Compound E is 1 0-150 mg./l.

Compound F.-Porphyrine naphtha-1,8 sultone, resulting from the reaction of one mole of porphyrine (substituted porphine) and two moles of naphtho-l,8 sultone. Optimum quantity of Compound -F is the same as E.

Compound G.Su-ccinimide naphthol,8 sultone, resulting from the equimolar reaction of succinimide and naphtho-1,8 sultone. Optimum quantity of Compound G is 50-500 mg./ 1.

The preparation of Compounds A to G is carried out by the following exemplary procedure:

In a reflux apparatus is placed in stoichiometric proportions (for example, equimolar in the case of Compounds A, B, D and G), the pentagonal, nitrogen-containing heterocyclic compound containing the labile hydrogen, and then the sultone is added to the pentagonal heterocyclic compound. Water is then added as is acid, such as HCl, to bring the pH to 3.5-4.0. The resulting mixture is heated at first progressively to 50 C. until the sulfone dissolves and then the mixture is 'heated to approximately 85 C. The mixture is then held at about 85 C. for about four hours. The viscosity of the liquid rises and it becomes syrupy. The mixture is then cooled to ambient or room temperature.

The solution thus-obtained can be used directly as a levelling agent under conditions specified above. Baths containing a levelling agent according to the invention give nickel deposits, which are adherent, ductile and virtually perfectly levelled, without pits or porosity.

What is claimed is:

1. An aqueous acidic nickel electrodepositing bath containing a source of nickel ions and as a levelling agent the condensation reaction product of naphtho-hS-sultone with a heterocyclic aromatic compound containing at least one five-membered heterocyclic ring including at least one ring nitrogen atom and at least one labile hydrogen atom and prepared by heating an aqueous liquid admixture of the naphthosultone and the heterocylic aromatic compound present in at least a stoichiometric amount under acid conditions to a reaction temperature above 65 C. but below C., maintaining the liquid admixture at a reaction temperature within the range aforesaid until the viscosity of the liquid increases appreciably and the liquid is of a syrupy consistency, and thereafter cooling the liquid admixture to room temperature, the condensation reaction product being present in the bath in an amount sufficient to yield levelled nickel electrodeposits.

2. The bath of claim 1 wherein the naphtho-1,8-sultone and the heterocyclic aromatic compound are reacted together at the reaction temperature maintained above 65 C. but below 100 C. in a molar ratio within the range of about 1-4 moles of the naphthosultone per mole of the heterocyclic aromatic compound.

3. An aqueous acidic nickel electroplating bath containing a source of nickel ions and as a levelling agent the condensation reaction product of naphtho-1,8-sultone with a heterocyclic aromatic compound containing at least one five-membered heterocyclic ring including at least one ring nitrogen atom and at least two labile hydrogen atoms and prepared by heating an aqueous liquid admixture of the naphthosultone and the heterocyclic aromatic compound present in at least a stoichiometric amount under acid conditions to an elevated temperature below 65 C., maintaining the admixture at the elevated temperature below 65 C. until the naphthosultone dissolves in the aqueous liquid, then heating the resulting liquid solution to a reaction temperature above 65 C. but below 100 C., maintaining the solution at a reaction temperature above 65 C. but below 100 C. until the viscosity of the liquid solution increases appreciably and the solution is of a syrupy consistency, and cooling the thus-treated solution to room temperature, the condensation reaction product being present in the bath in an amount sufficient to yield levelled nickel electrodeposits.

4. The bath of claim 3 wherein the heterocyclic aromatic compound is an indolinine.

-5. The bath of claim 3 wherein the heterocyclic aromatic compound is a B-nitrosoindole.

6. The bath of claim 3 wherein the heterocyclic aromatic compound is a phthalocyanine.

7. The bath of claim 3 wherein the heterocyclic aromatic compound is a dimethyl-1,5-imidazole.

8. The bath of claim 3 wherein the heterocyclic aromatic compound is selected from the group consisting of porphine and porphyrins.

9. The bath of claim 3 wherein the condensation reaction product is present in the bath in amount from about 5-600 m'g./l.

10. The bath of claim 3 wherein the pH of the bath is between 3.0 and 5.5.

11. The bath of claim 3 wherein the aqueous liquid admixture of the naphthosultone and heterocyclic aromatic compound is at a pH of about 3.5-4.0 during the heating thereof to an elevated temperature below 65 C.

12. A composition well suited as a levelling additive for a nickel electroplating bath comprising a solution in an inert liquid solvent of the condensation reaction product of naphtho-1,8-sultone with a heterocyclic aromatic compound containing at least one five-membered heterocyclic ring including at least one ring nitrogen atom and at least one labile hydrogen atom and prepared by heating an aqueuos liquid admixture of the naphthosultone and the heterocyclic aromatic compound present in at least a stoichiometric amount under acid conditions to a reaction temperature above 65 C. but below 100 C., maintaining the liquid admixture at a reaction temperature within the range aforesaid until the viscosity of the liquid increases appreciably and the liquid admixture is of a syrupy consistency, and thereafter cooling the liquid admixture to room temperature.

13. The composition of claim 12 wherein the five-membered heterocyclic ring contains at least two labile hydrogen atoms.

14. The composition of claim 12 wherein the acqueous liquid admixture of the naphthosultone and heterocyclic aromatic compound is at a pH of about 3.5-4.0 during the heating thereof to a reaction temperature above 65 C. but below 100 C.

15. In a method for the electro-depositing of nickel, the improvement which comprises effecting the nickel electrodeposition from an aqueous acidic nickel electrodepositing bath containing a source of nickel ions and as a levelling agent a bath-campatible condensation reaction product of naphtho-1,8-sultone with a heterocyclic aromatic compound containing at least one five-membered heterocyclic ring including at least one ring nitrogen atom and at least one labile hydrogen atom and prepared by heating an aqueous liquid admixture of the naphthosultone and the heterocyclic aromatic compound present in at least a stoichiometric amount under acid conditions to a reaction temperature above 65 C. but below 100 C., maintaining the liquid admixture at a reaction temperature within the range aforesaid until the viscosity of the liquid increases appreciably and the liquid is of a syrupy consistency, and thereafter cooling the liquid admixture to room temperature, the condensation reaction product being present in the bath in an amount sufiicient to yield levelled nickel electrodeposits.

16. In a method for the electroplating of nickel, the improvement which comprises effecting the nickel electroplating from an aqueous acidic nickel electroplating bath containing a source of nickel ions and as a levelling agent a bath-compatible condensation reaction product of naphtho-1,8-sultone with a heterocyclic aromatic compound containing at least one five-membered heterocyclic ring including at least one ring nitrogen atom and at least two labile hydrogen atoms and prepared by heating an aqueous liquid admixture of the naphthosultone and the heterocyclic aromatic compound present in at least a stoichiometric amount under acid conditions to an elevated temperature below C. until the naphthosultone dissolves in the aqueous liquid, then heating the resulting liquid solution to a reaction temperature above 65 C. but below C., maintaining the solution at a reaction temperature above 65 C. but below 100 C. until the viscosity of the liquid solution increases appreciably and the solution is of a syrupy consistency, and cooling the thus-treated solution to room temperature, the condensation reaction product being present in the bath in an amount sufficient to yield levelled nickel electrodeposits.

References Cited UNITED STATES PATENTS 1,564,414 12/1925 Hoff 204-50 1,915,334 6/1933 Salzberg et al. 260-243 2,075,359 3/1937 Salzberg et al 16722 2,469,727 5/1949 Hoffman 20449 2,849,352 8/1958 Kirstahler et al. 20449 XR 2,850,507 9/1958 Gaertner 260327 2,876,177 3/1959 Gundel et al 20449 3,122,490 2/1964 Strauss 20449 FOREIGN PATENTS 622,565 6/1961 Canada. 868,898 5/1961 Great Britain.

JOHN H. MACK, Primary Examiner.

G. KAPLAN, Assistant Examiner.

US. Cl. X.'R. 260326, 309, 314.5