CA1255622A - Process for electrodepositing copper - Google Patents

Abstract

Abstract of the Disclosure A process for electrodepositing a substantially uniformly hard, bright, leveled and ductile engineering copper plate on a conductive substrate, and particularly, on rotogravure printing cylinders, which copper deposit is further characterized as being substantially non-annealing thereby retaining its hardness for prolonged time periods following the electroplating step rendering the plate eminently suitable for mechanical engraving. The process employs an aqueous acidic copper electrolyte containing controlled amounts of a selected combination of organic brightening agents and the electrodeposition of the copper plate is performed under controlled processing conditions at a selected threshold current density to attain a copper deposit possessing the aforementioned beneficial characteristics. The combination of organic brightening agents includes an organic polyether compound, an organic sulfide compound, an apo safranine compound, a substituted phthalocyanine compound and an alkylated polyethyleneimine reaction product having a quaternary nitrogen.

Description

C~se No. ~-11,088 PROOESS FOR ELECTRCDEPOSIT~ COPPER

BackgroUnd of the Invention .
me process c~nprising the present invention broadly relates ~o the electrodeposition of copper deposits Gn conductive substrates, and more particularly is directed to the electroplating of rotGgravure cylinders employed for printing providing an engineering copper plate ~hich is eminent.Ly suitable for subsequent mechanical engraving.
A variety of copper electrolyte c~npositions ar.d processes have heretofore been employed for depositing a copper plate on the surfaces of rotogravure cylinders at a thickness sufficient to enable subsequent engraviny thereof. Copper electrolytes of the type employed for depositing a bright decorative copper plate provide for good leveling and ductility of the copper deposit but are subject to the disadvantage that the copper deposit after deposition i.s sel.f-annealing ~hereby the deposit becomes progressively soSter foll~ng the plating step rnaking the deposit unsatisfactory for rnechanical engraving such as by employing a diamond sty]us. Alternat-ively, copper el,ectro-lytes have been ernpl.oyed whlch do not give rise to self-annealing but such copper plates are characterized by Illeir dull. matte ap-pearance with poor leveling necessi,tating mecllanica'l ~inistl.illg such as by polishing of the copper deposil t,o l~lace :it in condiTionfor subsequent engravi,ng.

,., ~ .

The present inver.tion provides for a process empl~ying an aqueouS acidic copper electrolyte which under controlled conditions iS effective to deposit a suhstantiall~ uniformly hard, non-annealing, bright, leveled and ductile engineerirg copper deposit which substantially eliminates or minimizes subsequent mechanical finishing operations of the copFer deposit and wherein the copper deposit itself is of satisfactory hardness in spite of standing for prolonged time periods follcwing the electrodeposition step to enable satisfactory engraving by various mechanical means. The process is further characterized as being of simple and econcmical control and operation for achieving consistent copper plates of the desired mechanical properties.

Summary of the In~ention The benefits and advantages of the present invention are based on the discovery of a process employing an aqueous acidic copper electrolyte of a controlled ccmposition which under controlled operating parameters is operative for electro-depositing a highly leveled, ductile, bright and substantiallyuniformly hard engineering copper plate which is of a non-annealing character thereby retaining its hardness for prolonged time periods following the electrodeposition step enabling the plate to be engraved by mechanical engraving techniques and the like.
The copper electrolyte camprises an aqueous acidic solution containing copper in an amount sufficient to 1~5~

electrodeposit copper on a substrate and a controlled csmbination of bath soluble and compatible organic brightening agents including:
(1) an organic polyether ccmpound and mixtures thereof;

(2) an organic sulfide compound and mixtures thereof;
and

(3) at least one compound selected from each of the grouPs consisting of:
(A) A oompound corresponding to the structural formula A, FORMULA A

2 ~ N ~ ~ ~

R2 f I (~ X~3 ¢~ -Wherein R~ and R2 are radical.s sel.ected frolll the grGup consisting of hydrogen, methyl and ethyl. rad.i.cals, X is an anion selected from the group consisting of chlori.de, brosnide, i.odide, fluori.de, sulfate, bisul.fate and nitrate, `~ is H,-NH2,-N~CH3)2 and ~N=N-Z, and Y, is an ar~l~tic radi.cal selected from the group consisti.ng of phen~l., napht:hyl, and phenyl and naphthyl radicals substitllte<l ~7i.th arni.llcJ, 21kyl substituted amino, hydroxy and a.lko~y substituent groups;
(B) a substituted pht}laL-.~vallirle compound corresponding to formula B, FOR~ B
Pc - (X')n wherein:
Pc is a phthaloc;yanine radical.;
X' is -~2~R2'-S03M~-cH2sc(NR2)2 R is H, alkyl containi.ng 1-6 carb~n at~s, aryl con-taining 6 carbon atomLC~ aralJ~l containing 6 carbon atol~s in the aryl portiorl and 1 to 6 car~-ion atcms in the aLkyl porti.on, heterocyclic containing 2 to 5 carbon atollls and at least ]
nitrogen, oisygen, sulfur or phosphorus atcm, and aLkyl, aryl, aralkyl and heterc~clic, as defined above, containing 1 to S amirlo, hydro~y, sulfonic or phosphonic groups;
n is 1-6;
Y' is halogen or al.kyl. sul.fate conlainjllg I t-o 4 carbon atoms i.n the alkyl port:i.on; a M is ~I, Li, Na, K or Mg;
'I

..~v-, , ~,, 5C~

2~

(C) an alkylated polyethyleneimine reaction pro-duct having a quaternary nitrogen, as well as mixtures of (A), (B) and (C).
The organic 'orightening agents in the aqueous acidic electrolyte are present to provide a concentration of the polye-ther compound within a range of about 0.001 to about 5 grams per liter (g/1), the organic sulfide compound in a concentration of about 0.0005 to about 1 g/l, and a concentration of the brighteners comprising group (3) in admixture of about three or more present in an amount of at least about 25 milligrams (m g/l) with concentrations up to about 0.5 g/l being usable.
In accordance with the process aspects of the present invention, the aqueous acidic copper electrolyte is employed at a temperature of about 15 to about 38C
(about 60-100F) and the deposition of copper on a conductive substrate is performed at a cathode c~rrent density of at least about 6.5 amperes per square decimeter (60 ASF) up to as high as about 32.4 amperes per square decimeter (300 ASF) to produce an engineering copper deposit of at least about 0.025 millimeter (0.001 inch) thick. A conforming anode or plurality of anodes are employed to avoid any low current density areas less than about 6.5 amps per sq. dm. (60 ASF) and to further assure a substantially uniform thickness of copper deposit on the substrate.
Additional benefits and advantages of the present invention will become apparent upon a reading of ~he nescr;D-tion of the Preferred Embodiments taken in conjunction with the accompanying examples.

Description of ~he Preferred Embodiments In accordance with the practice of the process of the present invention, an aqueous acidic electrolyte is pr~Jided which may be of the sulfate type typically containing about 180 to about 250 g/l of copper sulfate and about 30 to about 80 g/l of sulfuric acid. Alternatively, fluoroborate baths can be prepared typically containing from about 200 to about 600 g/l of copper fluoroborate and up to about 60 g/l of fluoboric acid. It is also contemplated that copper nitrate salts or copper sulfamate salts can be employed in approximately equivalent proportions for copper sulfate and the electrolyte can be acidified employing equivalent amounts of phosphoric acid, nitric acid, sulfamic acid or sulfuric acid. In accordance with the preferræ practice of the present mvention, sulfate-type copper baths are employed.
The aqueous electrolyte may further incorporate halide ions such as chloride and/or bramide ions in an amount up to about 0.2 g/l. Concentration of halide ions in excess of about 0.2 g/l have been found undesirable in some instances due to a loss in the ductility of the copper deposit.
me unique non-annealing characteristics of the copper deposit in further combination with the desirable physical characteristics thereof are achieved by employing a specific ccmbination of organic brighteners of the types as hereinbefore set forth. The preferred organic polyether compounds are bath soluble and ccmpatible polyethers containing at least 4 ether ~5~

oxygen atoms and having an average molecular weight ranging from about 180 up to 1,000,000. Particul~rly satisfactory results are obtained with polypropylene and polyethylene glycols includir.g mixtures of the foregoing of an average ~olecular weight of about 600 to akout 6,000, alkoxylated aromatic alcohols having a lecular weight ranging from about 300 to 2500 and alkoxylated amines having a molecular weight of about 1000 to about 50,300.
Exemplary of such preferred polyether brightening ccmpounds which can satisfactorily be employed are polyethylene glycols of an average molecular weight of from about 400 to about 1,000,000;
ethoxylated naphthols containing 5 to 45 mols ethylene oxide groups; propoxylated naphthols containing 5 to 15 mols of propylene oxide g,roups; ethoxylated nonyl phenol containing 5 to 30 mols ethylene oxide groups; propylene glycols of an average ~olecular weight of about 350 to a~out 1,000; block polymers of polyoxyethylene and polyoxypropylene glycols of an average molecular weight of about 350 to 250,000; ethoxylated phenols containing 5 to 100 mols of ethylene oxide groups; propoxylated phenols containing 5 to 15 mols of propylene oxide groups, and ethylene diamune blcck polymers having a lecular weight of about 1600 to about 30,000. Additional polyether ccmpounds suit~ble for use in the practice of the present process are those disclosed in United States Patent No. 4,272,335.
The polyether brightening com~ounds are employed in a range of about 0.001 up to about 5 g/l with the lower concentrations generally being used with the higher molecular weight polyethers.

The organic sulfide brightening compound (2) 1,Jhich can be satisfactorily employed in the practice of the present process includes the various organic sulfide sulfonic co~ounds as described in United States Patent No. 3,267,010, and particu-larly Table I thereof; organic sulfur compounds as disclosed in United States Patent No. 4,181,582 and particularly Table III
thereof; and the organic polysulfide compounds as disclosed in United States Patent No. 3,328,273 and particularly Table I there-of. The organic sulfide compounds containing sulfonic or phos-phonic groups may also contain various substituent groups, such as methyl, chloro, bromo, methoxy, ethoxy, carboxy or hydroxy, on the lecules, especially on the aromatic and heterocyclic sulfide-sulfonic or phosphonic acids. Such compounds may be used as the free acids, the alkali metal salts, organic amine salts, or the like.
other suitable organic divalent sulfur compounds which can be satisfactorily used include HO3P-(CH2)3-S-S-(CH2)3-PO3H, as well as mercaptans, thio-carbamates, thiolcarbamates, thioxanthates, and thiocarbonates which contain at least one sulfonic or phosphonic group.
A particularly preferred group of organic divalent sulfur compounds as described in U.S. Patent No. 3,328,273 are the organic polysulfide c~mpounds of the formula XR1-(S)nP.2SO3H
or XR1-(S)nR2PO3H wherein Pl and R2 are the sam~ or differer~
a ~71ene group containing fram about 1 to 6 carkon atcms, X is hydrogen, SO3H or PO3H and n is a number frGm about 2 to 5.
These organic divalent sulfur compounds are aliphatic polysulfides wherein at least two di~lent sulfur atcms are vicinal and wherein the molecule has one or two terminal sulfonic ox phosphonic acid groups. The alkylene portion of the molecule may be substituted with groups such as methyl, ethyl, chloro, brcmo, ethoxy, hydroxq~, and the like. These compounds may be added as the free acids or as the alk~l; metal or amine salts.
The organic sulfide brightening compound or mixture of ccmpounds are present in the electrolyte within a range of about 0.0005 to about 1 g/l.
In addition to the brightening agents (1) polyether compounds and (2) sulfide compounds, the electrolyte further contains as an essential brightening agent at least three brightener ~ ~pounds (3) ccmprising compounds (A), IB), and.
~C). Brightening comFound (A) corresponding to Formula A as hereinabove set forth may typioally ccmprise those as set forth in United States Patent No. 2,882,209, and specifically Table II
. thereof. Such typical brighteners include Diethyl safranine azo dimethyl aniline - Janus Green B, Diethyl safranine azo phenol - Janus Black, Safranine azo naphthol - Janus Blue, Janus Gray (Color Index 137, Society of Dyers ~ Colourists, by F. M.
Rowe, 1924), Dimethyl safranine azo dimethyl aniline, ~;~s~

:
Phenosafranine, Fuchsia, Amethyst Violet, and the like.
Brightening ccmpounds corresponding to Formula A can be empl~yed ~ithin a range up to akout 0.5 g/l with concentrations of abcut 25 to about 50 mg/l being preferred.
The brightening agent corresponding to Formula B
comprises a substituted phthalocyanine radical which may be metal-free or which may contain a stable divalent or trivalent metal bound by coordination of the isoindole nitrogen at~ns of the molecule, which metal is selected from the group consisting of cobalt, nickel, chro~ium, iron or copper, as well as mixtures of the foregoing of which copper is th~ more typical ar.d preferred metal. Such phthalocyanine compounds suit~ble for use in the practice of the present process are those having a ~ath solubility of at least about 0.1 mg/l and are employed in concentrations up to about 0.5 g/l with concentrations of about ~5 to about 50 mg/l being preferred. Suitable phthalocyanine ccmpounds correspond to the structural formula:

~0 ~i)b \==~

(X~ N ( ~ ~ (X~b '' ~\~
(X)b hherein:
X is as has keen heretofore defined;
Z is Ni, Co, Cr, Fe or Cu;
a is 0-1; and B is 0-2, prDvided however thAt the total number is X substituents is 1-6.

Substituted ph~halo~yanine compounds suitable for use in the practice of the present invention further include those as described in Uhited States Patent No. 4,272,335. A particularly preferred phthalocyanine compound comprises Alcian slue.

S~2~

The organic brightening compound (C) co~prises a reaction product of polyethyleneimine and an organic compound which will alkylate the nitrogen of the polyethyleneimine to produce a quaternary nitrogen. Compounds of the foregoing type satisfactory for use in the practice of the present process are disclosed in United States Patent No. 3,770,598. The alkylating agent may comprise aliphatic and aromatic compounds which may be either saturated or unsaturated. Compounds which have proved to be of particular value are organic compounds which contain active halogens, such as the aralkyl halides, the alkyl, alkenyl and alkynyl halides, acid halides, acyl halides, and the like.
Additionally, compounds such as the alkyl sulfates, alkyl sul-tones, aldehydes, ketones, isocyanates, thioisocyanates, - epoxides, acylamides, acids, anhydrides, ureas, cyanamides, guanidines, and the like, may also be used. It is to be appre-ciated that in some instances organic compounds may be used in which the reacting group is attached directly to an aromatic nucleus, rather than on an alkyl chain. Exe~plary of such materials is 2,4-dinitrochlorobenzene, which will react with either the primary or secondary nitrogen of the polyethyleneimine and/or will quaternize with the tertiary nitrogen. Accordingly, in referring to the "alkylation" of the nitrogen in the polyethyleneimine, it is intended to include those cases in which the nitrogen is attached directly to an aryl or aromatic nucleus, i2~
~ .

as well as those in~which it is attached to an aliphatic group.
Specific compounds which have been found to give particulæly good results are benzyl chloride, allyl bromide, dimeth~l sulfate, and propane sultone. These compounds, h~lever, æe merely exemplary of the organic ccmFounds which will alkylate t~e nitrogen of the polyethyleneimine. Preferably the aIkylatir.g agent is an aromatic halide.
~ ?hen the alkylating agent reacts with the primary or secondary amine; it will be altered to the secondary and tertiary amine, respectively. This is accGmplished by adding more alkylating agent as is desired. Where the alkylation takes place at the primary and/or secondary nitrogen, there will ke a splitting off of the alkylating groups on the organic ccopound, e.g., halogen, sulfate, or the like. In the case of the tertiary nitrogen, hcwever, a quaternization takes place, forming the quaternary salt.
It is pre~erred that as many nitrogen atoms as possible in the polyethyleneumine brightener should be quaternized, although as little as 5 percent of the nitrogen atoms being quaternary still gives desirable results, with lOpercent being more preferred and even more preferably 20 percentO
me polyethyleneimine which is used in forming the brighte~lng agent additive may have a wide rarge of molecular weights. Typically, the molecular weight of the polyethyleneimine may be within the range of about 300 to several 1~ 5~
., millions. In many instanceS, haw~v~r, molecular ~eights within the range of about 300 to l,000~000 are preferred. The organic brightening ccmpound (C) is employed in am~unts up to a~out 0.5 g/l with concentrations of akout 35 to about 100 mg/1 being preferred.
The organic brightening agents (A), (B) and (C) are employed in combination of at least three in an amount of at least about 25 mg/l with concentrations up to about 0.5 g/l beir.g satisfactory while amounts of about 30 to about 90 mg/l being preferred.
In accordance with the practice of the process of the present invention, an electrolyte of the foregoing camposition is employed in which an electrically conductive substrate is immersed and is cathodically charged for a period of time to deposit the desired thickness of copper thereon. During the electroplating operation, the bath is controlled within a temperature of about 60 up to about 100F with temperatures of from about 70 up to about 90F being typical and preferred.
Temperatures above about 100F are undesirable in many instances due to the tendency to form copper deposits which are of reduced ductility. The electrodeposition of the copper plate is performed at a current density of at least about 60 ASF to current densities as high as about 300 ASF and even higher in specialized instances. Preferably, the cathode current density is controlled within a range of about 100 to about 200 ASF. In ~5~
,, order to achieve a substantially uniform thickness of cc~per plate on the substrate, it is preferred that an anode arrange~ent is employed ~hich provides for a substantially uniform current density on the cathode over substantially the entire surface thereof. For this purpose, in accordance with conventional practice in the electroplating of rotogravure cylinders, a conforming anode, or in the alternative, a plurality of anodes disposed at spaced intervals are employed so as to achieve a substantially uniform cathode current density.
The unique copper plate deposited in accordance with the practice of the present invention which is bright, leveled, ductile, substantially pure copper is eminently adapted for a variety of engineering applications such as for electroforming molds, manufacture of audio and video discs, for rotogravure cylinders and the like. The copper plate is further characterized as being of relatively uniform hardness, usually above 200 Diamond Pyramid Hardness Number at a 100 gram load and further characterized by a highly uniform, homogeneous, equiaxed crystalline structure of a grain size less than about 1 micron.
The engineering ccpper deposit produced by the present process is distinguishable from conventional decorative copper deposits because of the thickness ~7hich is at least about 0~001 inch to as high as 0.050 inch and even thicker as weIl as in the unique nonannealmg characteristics of the engineering copper plate.
me process of ~he present invention furthermore, is inapplicable for producing so-called decorative copper deposits due to the ~s~

formation of dark striations in all :lc~w currer)t del1si ty areas havin~ average cathode urrent densi ties belc~/ 6(~ ASF ~Jhich renders such decorative deposit unacceptable.
In order to Eurther illust:rate the proces, of the present invention, the fol].owi.ng typi.c~l. exan~les are prov;ded.
It will be appreciated that the e~cunp 1 es are pr.ovi.ded for illustrative purposes and are not intende(l to 1~ I.imi.tinc3 of the scope of the present i.nvention as herein descri bed and as set forth in the subjoinecl claims.

An aqueous acidic copper e Lectrolyte is prepared containing about 195 g/l of copper sulfate pentahydrate, 75 g/l of sulfuric acid, about 20 to about 100 mg/l chloride ions and a combination oE organic brightening agents comprising brighteners ( 1 ) po].ypropylene oxide (mol wt. 750) present in an amollnt of about 120 mg~
(2) Bis (3-sulfopropyl disulEide disodium salt) present in an amount of about 21 mg/l, brightener (3) corresponding to Formula (A ) compri.si.ng Janus Green B
present in amount of about 15 mg/:l, brightener (3) correspond i ng to Formul a ( B ) compr i. s i ng Me th i c Turql~o i se present in an amount of about 15 mg/l and brightener ( 3) (C) comprising polyethyleneimine quaterni zed with benzyl chloride present in an amount of about 12 mg/l.
The bath is controlled at a ten~era-t ure of about 80F
and a roto~.ravure cylinder is i~ersed in t he bath surrounded by conforming copper anodes while being Lotatecl at lO0 rpm and electric current is passed between the anodes and catlll)dical1y chanJed work piece to provide a cathocle currenl dellsily oE about l5() ASF.

~16 .. ,~ . .

The resultant copper deposit is observed to be fully bright wi~h good leveling, good ductility and of a substantially uniform hardrless above 200 Diamond Pyramid Hardness Nu~ber at a 100 gram load (DPH~. The copper deposit is substantially non-annealing as evidenced by no significant reduction in hardness after stardirg for a period of 48 hours following the electrodeposition of the copper plating.

EX~MPLE 2 An aqueous acidic copper electrolyte is prepared containing about 195 g/l of copper sulfate pentahydrate, 75 g/l of sulfuric acid, akout 20 to akout 100 mg/l chloride ions and a ccmbination of organic brightening agents comprising brighteners (1) polyethylene oxide ( 1 wt. 3350) present in an amount Or akout 60 mg/l, (2) Bis (3-sulfopropyl disulfide disodium salt) present in an amount of about 30 mg/l, and brightener (3) corresponding to Formula (A) comprising Janus Green ~ present in an amount of a~out 10 mg/l, Methic Turquoise corresponding to formula B present in an amount of 10 mg/l and 10 mg/l of brightener (3)(C) comprising polyethyleneimine quaternized with benzyl chloride.
The bath is controlled at a temperature of akout 75F
and a rotogravure cylinder is immersed in the bath surrounded by conforming copper anodes while rotated at 3Q0 rpm and electric current is passed between the anodes and cathodically charged work piece to provide an average cathcde current density of about 100 ASF. The resultant copper deposit is observed to be fully bright, leveled and ductile with a hardness above about 200 DPH
at 100 gram load. The resultant copper deposit is substantially nonannealing.

EYl~PLE 3 An aqueous acidic copper electrolyte is prepared containing about 195 g/l of copper sulfate pentahydrate, 75 g/l of sulfuric acid, about 20 to about 100 mg/l chloride ion5 and a combination of organic brightening agents comprising brighteners (1) polypropylene oxide (mol wt. 750) present in an amount of about 120 mg/l, (2) Bis (3-sulfopropyl disulfide disodium salt) present in an amount of about 30 mg/l, and brightener (3) corresponding to Formula (A) comprising Janus Green B present n an amount of about 8 mg/l, brightener (3) corresponding to Formula ~B) comprising Methic Turquoise present in an amount of about 22 mg/l and brightener (3) corresponding to Formula (C) comprising polyethyleneimine quaternized with benzylchloride present in an amount of about 3 mg/l.
The bath is controlled at a temperature of about 70F
and a rotogravure cylinder is immersed in the bath surrounded by conforming copper anodes while rotated at 180 rpm and electric current is passed between the anodes and cathodically ~harged work piece to provide an average cathode current density of about 150 ASF. The resultant copper deposit is observed to be fully bright, leveled and ductile with a hardness above 200 DPH at a 100 gram load. me copper deposit is suhstantially nonannealing.

While it will be appQrent that the preferred emaxln~nts of the invention disclosed are well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to mcdification, variation and change without departing frcm the proper scope or fair meaning of the subjoined claims.

Claims (8)

The embodiments of the invention in which an exclusive property or privilege is claimed are define as follows.

1. A process for electrodepositing a highly leveled, ductile bright, substantially uniformly hard nonannealing engineering copper plate on a conductive substrate comprising the steps of providing an aqueous acidic solution at a temperature of about 15° to about 38°C and containing copper in an amount suf-ficient to electrodeposit copper on a substrate and a controlled combination of bath soluble and compatible organic brightening agents including:
(1) about 0.001 to about 5 g/l of an organic polyether compound and mixtures thereof;
(2) about 0.0005 to about 1 g/l of an organic sulfide compound and mixtures thereof; and (3) about 25 mg/l to about 0.5 g/l of at least one compound selected from each of the groups consisting of:
(A) a compound corresponding to the structural formula A, FORMULA A

wherein R1 and R2 are radicals selected from the group consisting of hydrogen, methyl and ethyl radicals, X is an anion selected from the group consisting of chloride, bromide, iodide, fluoride, sulfate, bisulfate and nitrate, Y is H,-NH2,-N(CH3)2 and -N=N-Z, and Z is an aromatic radical selected from the group consisting of phenyl, naphthyl, and phenyl and naphthyl radicals substituted with amino, alkyl substituted amino, hydroxy and alkoxy substituent groups;
(B) a bath soluble, substituted phthalocyanine compound corresponding to formula B, FORMULA B
Pc - (X')n wherein:
Pc is a phthalocyanine radical;
X' is -SO2NR2,-SO3M,-CH2SC(NR2)2+Y-;
R is H, alkyl containing 1-6 carbon atoms aryl containing 6 carbon atoms, aralkyl containing 6 carbon atoms in the aryl portion and 1 to 6 carbon atoms in the alkyl portion, heterocyclic containing 2 to 5 carbon atoms and at least 1 nitrogen, oxygen, sulfur or phosphorus atom, and alkyl, aryl, aralkyl and heterocyclic as defined above, containing 1 to 5 amino, hydroxy, sulfonic or phosphonic groups;
n is 1-6;
Y' is halogen or alkyl sulfate containing 1 to 4 carbon atoms in the alkyl portion; and M is H, Li, Na, K or Mg;
(C) an alkylated polyethyleneimlne reaction product having a quaternary nitrogen, as well as mixtures of (A), (B) and (C);
immersing a cathodically charged conductive substrate in said solution, passing electric current through said solution at an average cathode current density of about 6.5 to 32.4 amps per sq.
dm. and electrodepositing an engineering copper plate on said substrate to a thickness of at least about 0.025 millimeter.

2. The process as defined in claim 1 in which said brightening agents (3) are present in an amount of about 30 to about 90 mg/l.

3. The process as defined in claim 1 including the further step of controlling the temperature of said aqueous acidic solution during the step of electrodepositing the copper plate within a range of about 15° to about 38°C.

4. The process as defined in claim 1 including the further step of controlling the temperature of said aqueous acidic solution during the step of electrodepositing the copper plate within a range of about 21° to about 32°C.

5. The process as defined in claim 1 in which the step of electrodepositing a copper plate on said sub-strate is performed at an average cathode current density of about 10.8 to about 21.6 amps per sq. dm.

6. The process as defined in claim 1 in which said aqueous acidic solution further contains halide ions up to about 0.2 g/l.

7. The process as defined in claim 1 in which said conductive substrate comprises a rotogravure cylinder immersed in said solution and including the further step of rotating said cylinder during the step of electrodepositing said copper plate thereon to provide a substantially uniform thickness of copper plate thereon.

8. An article having on its surface an engineer-ing bright, leveled, ductile, substantially nonannealing, substantially pure copper deposit comprising a matrix of highly uniform, homogeneous, equiaxed crystalline structure of an average grain size less than about 1 micron, said crys-talline structure further characterized as being stable with-out the tendency to recrystallize after electrodeposition.