Brighteners for electrolytic acid zinc baths
OwnerFrancine Popescuinventor
Life of this patent
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Abstract
Brighteners for electrolytic acid zinc baths having the general formula: ##STR1## About 0.05 to 2.0 grams brightener are added for every liter of zinc bath to produce bright ductile zinc electrodeposits. Several types of wetting agents are used as dispersants in the zinc bath which has a pH of about 3.0 to 6.8. Other known brighteners may be added to the bath to obtain variations of the quality of the zinc deposits.
Claims9
A bright zinc electroplating bath comprising an aqueous acidic solution of zinc ions and:
- (a) 0.1 to 30.0 grams per liter of a dispersing agent compatible with said bath;
- and,
- (b) 0.05 to 2.0 grams per liter of a brightener of general formula:
- ##STR19## wherein:
- R.sub.1 is a phenyl, pyridyl or naphthyl radical which may comprise one or several substituents selected from:
- hydroxy, chloro, bromo, alkyl, alkoxy, carboxy, amino, amido or methylenedioxy;
- N is zero or 1
- R.sub.2 is hydrogen, hydroxy or methyl when n is 1;
- R.sub.2 is hydroxy or methyl when n is zero;
- R.sub.3 is hydrogen, hydroxy or methyl;
- R.sub.4 is an alkyl of at least two carbon atoms, hydroxyalkyl or pyridyl when R.sub.1 is phenyl, R.sub.2 is hydrogen and n=0;
- and
- R.sub.4 is alkyl, hydroxyalkyl or pyridyl in any other case.
A method of electroplating bright zinc comprising making a metallic object, the cathode in an aqueous acidic electroplating bath, said bath comprising zinc ions and:
- (a) 0.1 to 30.0 grams per liter of a dispersing agent compatible with said bath;
- and,
- (b) 0.05 to 2.0 grams per liter of a brightener of general formula:
- ##STR20## wherein:
- R.sub.1 is a phenyl, pyridyl or naphthyl radical which may comprise one or several substituents selected from:
- hydroxy, chloro, bromo, alkyl, alkoxy, carboxy, amino, amido or methylenedioxy;
- n is zero or 1;
- R.sub.2 is hydrogen, hydroxy or methyl when n is 1;
- R.sub.2 is hydroxy or methyl when n is zero;
- R.sub.3 is hydrogen, hydroxy or methyl;
- R.sub.4 is an alkyl of at least two carbon atoms, hydroxyalkyl or pyridyl when R.sub.1 is phenyl, R.sub.2 is hydrogen and n=0;
- and
- R.sub.4 is alkyl, hydroxyalkyl or pyridil in any other case.
A bright zinc electroplating bath comprising an aqueous acidic solution of zinc ions and:
- (a) 0.1 to 30.0 grams per liter of a dispersing agent compatible with said bath;
- and
- (b) 0.05 to 2.0 grams per liter of the brightener 3-methyl-4-phenyl-3-buten-2-one.
A bright zinc electroplating bath comprising an aqueous acidic solution of zinc ions and:
- (a) 0.1 to 30.0 grams per liter of a dispersing agent compatible with said bath;
- said dispersing agent being selected from the group consisting of:
- Sulphated ethoxylated fatty alcohol C.sub.12 -C.sub.14 with 20 moles of ethylene oxide and sulphated ethoxylated octylphenol with 12 moles of ethylene oxide;
- and
- (b) 0.05 to 2.0 grams per liter of a brightener of the general formula:
- ##STR21## wherein:
- R.sub.1 is a phenyl, pyridyl or naphthyl radical which may comprise one or several substituents selected from:
- hydroxy, chloro, bromo, alkyl, alkoxy, carboxy, amino, amido or methylenedioxy;
- R.sub.2 is hydrogen, hydroxy or methyl;
- R.sub.3 is hydrogen, hydroxy or methyl;
- n is zero or 1;
- R.sub.4 is an alkyl of at least two carbon atoms, hydroxyalkyl or pyridyl when R.sub.1 is phenyl, R.sub.2 is hydrogen and n=0;
- and
- R.sub.4 is alkyl, hydroxyalkyl or pyridyl in any other case.
Dependencies are inferred from the claim text.