Acid zinc electroplating process and composition

DETAILED DESCRIPTION This invention relates to a method of producing bright zinc electrodeposits over a wide current density range, which comprises passing current from a zinc anode to a metal cathode for a time period sufficient to deposit a bright zinc electrodeposit upon said cathode; the current passing through an aqueous acidic bath composition containing at least one zinc compound providing zinc cations for electroplating zinc, and containing as cooperating additives at least one bath soluble substituted or unsubstituted polyether, at least one aliphatic unsaturated acid containing an aromatic or heteroaromatic group and at least one aromatic nitrogen heterocyclic compound.
The bath soluble polyethers of this invention which may be used in amounts of about 1 to 50 g/l (preferably about 2 to 20 g/l) include polyethers of the following general types: C.
sub.
n H.
sub.
2.
sbsb.
n+1 (OC.
sub.
3 H.
sub.
6).
sub.
m.
spsb.
1 (OC.
sub.
2 H.
sub.
4).
sub.
m.
spsb.
2 OH where n = 6 to 14 m.
sub.
1 = 1 to 6 m.
sub.
2 = 10 to 20 exemplified by propoxylated ethoxylated lauryl alcohol having the following structure: CH.
sub.
3 (CH.
sub.
2).
sub.
11 (OC.
sub.
3 H.
sub.
6).
sub.
3 (OC.
sub.
2 H.
sub.
4).
sub.
15 OH h--oc.
sub.
3 h.
sub.
6).
sub.
n OH where n = 5 to 50 exemplified by polypropylene glycol 700 having the following structure: H--OC.
sub.
3 H.
sub.
6).
sub.
16 OH ##STR1## where R = represents an alkyl group containing 8 to 16 carbon atoms and n = 5 to 500 exemplified by nonylphenol polyethylene glycol having the following structure: ##STR2## where n.
sub.
1 and n.
sub.
2 may be the same or different, and vary from 5 to 500 exemplified by 2,5-dimethylhexane-2,5-polyethylene oxide having the following structure: ##STR3## H--OCH.
sub.
2 CH.
sub.
2).
sub.
n OH where n = 5 to 500 exemplified by polyethylene oxide having the following structure: H--OCH.
sub.
2 CH.
sub.
2).
sub.
136 OH ##STR4## where R.
sub.
1 and R.
sub.
2 are alkyl groups containing one to about 20 carbon atoms, which may be the same or different; R.
sub.
1 and/or R.
sub.
2 may also by hydrogen and n = about 5 to 250 exemplified by t-dodecylaminepolyethyleneoxide having the following structure: C