Electrodeposition of zinc and additives therefor
AssigneeW. Canning & Company Limited
InventorBarrie Sydney James
Life of this patent
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Abstract
Bright zinc plate is obtained from alkaline, cyanide-free zinc plating baths containing (a) at least one linear polyamine obtained by condensing an aliphatic diamine containing at least one tertiary amino group with a 1,3-dihalopropan-2-ol, and (b) at least one substituted pyridine compound in the form of a free base or as a quaternized derivative. A brightener composition containing the linear polyamine and the pyridine compound can be added to alkaline, cyanide-free zinc plating baths.
Claims17
In an aqueous alkaline, cyanide-free zinc electroplating bath containing zinc ions and hydroxyl ions, the improvement comprising said bath including an effective brightening amount of
- a. at least one linear polyamine obtained by condensing a diamine of the formula ##STR3## where R.sup.1 and R.sup.3, which may be the same or different, each represent an alkyl group with 1 to 4 carbon atoms, and R.sup.2 and R.sup.4, which may be the same or different, each represent a hydrogen atom or an alkyl group with 1 to 4 carbon atoms, and where m is an integer from 1 to 5, with a 1,3-dihalopropan-2-ol;
- together with
- b. at least one pyridine compound in the form of free base or as quaternised derivatives, in which the pyridine compound is a pyridine compound of Formula (IIa) or a pyridine compound having a cation of formula (IIb):
- ##STR4## where R.sup.5 represents a hydrogen atom or an alkyl group with 1 to 5 carbon atoms;
- and R.sup.6 represents a cyano group, a group --COOR.sup.7 where R.sup.7 represents a hydrogen atom, an alkali metal cation or an alkyl group with 1 to 5 carbon atoms;
- and R.sup.10 represents a radical selected from the group consisting of aralkyl, alkyl, alkenyl, esterified carboxyalkyl and hydroxyalkyl groups.
A brightener composition for addition to an alkaline, cyanide-free zinc electroplating bath, comprising a mixed solution of
- a. at least one linear polyamine obtained by condensing a diamine of the formula:
- ##STR5## where R.sup.1 and R.sup.3, which may be the same or different, each represent an alkyl group with 1 to 4 carbon atoms, and R.sup.2 and R.sup.4, which may be the same or different, each represent a hydrogen atom or an alkyl group with 1 to 4 carbon atoms, and where m is an integer from 1 to 5, with a 1,3-dihalopropan-2-ol;
- and
- b. at least one pyridine compound in the form of a free base or as a quaternised derivative, in which the pyridine compound is a pyridine compound of formula (IIa) or a pyridine compound having a cation of formula (IIb):
- ##STR6## where R.sup.5 represents a hydrogen atom or an alkyl group with 1 to 5 carbon atoms;
- and R.sup.6 represents a cyano group, a group --COOR.sup.7 where R.sup.7 represents a hydrogen atom, an alkali metal cation or an alkyl group with 1 to 5 carbon atoms;
- or a group --CONR.sup.8 R.sup.9 where R.sup.8 and R.sup.9 which may be the same or different each represents a hydrogen atom or an alkyl group with 1 to 5 carbon atoms;
- and R.sup.10 represents an aralkyl, alkyl, alkenyl, esterified carboxyalkyl or hydroxyalkyl group.
Dependencies are inferred from the claim text.