Polyamine brightening agent

1. A zinc or zinc alloy electroplating bath comprising:

zinc ions and a brightening agent, the brightening agent comprising at least one polyamine or a mixture of polyamines, the at least one polyamine or mixture of polyamines including a first repeating unit that has the general formula:

and a second repeating unit having the general formula:

where Δ 1 is O, N, or S; x is an integer from 2 to 6; y is an integer from 1 to 6; R 1 , R 2 , R 3 , and R 4 , which is the same or different, is methyl, ethyl, isopropyl, n-propyl, hydroxyethyl, or

—CH 2 CH 2 (OCH 2 CH 2 ) m OH; m is a number between 0-6; R 5 represents a group of atoms necessary to complete a heterocyclic compound having a five or six membered ring containing at least two nitrogen atoms; and R 6 is nothing or an alkyl group, wherein the first repeating unit and the second repeating unit are in the same polymer chain.

2. The zinc or zinc alloy electroplating bath of claim 1 , wherein the first repeating unit having the following formula:

3. The zinc or zinc alloy electroplating bath of claim 1 , wherein the polyamine includes a repeating unit having the following general formula:

4. A zinc or zinc alloy electroplating bath comprising:

zinc ions and a brightening agent, the brightening agent comprising at least one polyamine including a first repeating unit that has the general formula:

and a second repeating unit having the general formula:

where y is an integer from 1 to 6;

R 5 represents a group of atoms necessary to complete a heterocyclic compound having a five or six membered ring containing at least two nitrogen atoms, and R 6 is nothing or an alkyl group, wherein the first repeating unit and the second repeating unit are in the same polymer chain.

5. The zinc or zinc alloy electroplating bath of claim 4 , wherein the second repeating unit comprises:

6. The zinc or zinc alloy electroplating bath of claim 4 , wherein the polyamine includes a repeating unit having the following general formula: