# US 4,397,718 A · Zinc plating baths with condensating polymer brighteners

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 4,397,718 A
- Document ID: US4397718A
- Status: Granted
- Kind: A
- Application number: 06/381,090
- Filed: 1982-05-24
- Granted: 1983-08-09
- Earliest claimed: 1982-05-24
- Assignees: Occidental Chemical Corporation
- Inventors: Sylvia Martin
- Web page: https://patentgrep.com/patent/US4397718A

## CPC

- C25D 3/22: of zinc
- C25D 3/24: from cyanide baths
- C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR

## Abstract

A zinc plating bath comprises a conductive aqueous solution containing zinc ions and a brightening additive which is a derivative of .beta.-aminopropionic acid or a polymer thereof. A ductile zinc deposit having a uniform high degree of brightness can be electrodeposited from the bath onto a substrate.

## Claims

### Claim 1

A zinc electroplating bath comprising a conductive aqueous solution containing zinc ions and a brightening amount of a water soluble brightening additive selected from the group consisting of a monomer of the following general formula and polymers thereof: ##STR9## wherein: n is from 1 to about 6;
Y is --OX, --NX.sub.2, --SO.sub.3 H, --SO.sub.3 M, --COOH, --COOM, --SX, or --CN;
X is H, or an alkanol, alkamine, sulfoalkyl, carboxyalkyl, hydroxyaryl, sulfoaryl, carboxyaryl, or aminoaryl having from 1 to about 10 carbon atoms;
M is H, Li, Na, K, Be, Mg or Ca;
Q is --OR.sub.4, --N(R.sub.4).sub.2, --OZ, --OM, or halogen;
Z is an aryl group or a substituted aryl group having from about 6 to about 14 carbon atoms;
R.sub.1 is H or an alkyl group having from 1 to about 4 carbon atoms;
R.sub.2 is H or an alkyl, alkanol, or alkamine group having from 1 to about 4 carbon atoms, or ##STR10## R.sub.3 is H or an alkyl group having from 1 to about 4 carbon atoms, phenyl, substituted-phenyl, or ##STR11## R.sub.4 is H or an alkyl, alkenyl, alkynyl, alkanol, alkenol, alkynol, keto alkyl, keto alkynyl, keto alkenyl, alkamine, alkoxy, polyalkoxyl, sulfoalkyl, carboxyalkyl, mercapto alkyl, or nitriloalkyl group having from 1 to about 12 carbon atoms, phenyl or substituted phenyl or ##STR12## R.sub.5 is H, --OH, or a hydroxyalkyl group having from 1 to about 4 carbon atoms;
r is 1 to about 3;
and mixtures thereof.

### Claim 2 (depends on 1)

The bath of claim 1 wherein said brightening additive is selected from the group consisting of:
Poly[N-(2-hydroxyethyl) nitrilo di-(ethylpropionate)];
Poly[N-(2-hydroxyethyl) nitrilo di-(N'-(2-hydroxyethyl) propionamide];
Poly[N-(2-hydroxyethyl)-N-(2-cyanoethyl)-.beta.-amino propionic acid];
Tetra[N-methyl N-cyanomethyl .beta.-amino propionate] pentaerythritol;
Poly[N-(hydroxy tert-butyl).beta.-amino .beta.-methylcarboxy methyl propionate];
Poly[N-(2-hydroxypropyl).beta.-amino-.alpha.-methyl aceto methyl propionate];
Poly[N-(2-hydroxyethyl).beta.-amino-.beta.-phenyl methyl propionate];
Poly[.beta.-tauryl ethyl propionate];
Poly[N,N-di(2-hydroxyethyl)nitrilo .beta.-methyl propionamide];
Poly[N-(3-hydroxypropyl).beta.-aminopropionamide-(N'-isopropyl-sodium sulfonate];
Poly[N-(2-mercaptoethyl) nitrilo di(methyl propionate)];
Poly[N-(2-carboxyethyl).beta.-amine di(butyl propionate)];
Poly[N-(hydroxyethyl aminoethyl).beta.-amino(2-methoxyethyl) propionate];
Poly[N-(2-hydroxyethyl) nitrilo di-(2-ethyl hexyl propionate)];
N-(2-hydroxypropyl) nitrilo di-(polyethoxy propionate) where the molecular weight of the polyether group is 2000-4000;
Tetra[N-(2-hydroxyethyl .beta.-amino propionate] pentaerythritol;
and mixtures thereof.

### Claim 3 (depends on 1, 2)

The bath of claim 1 or 2 wherein said brightening additive is present in an amount of from about 0.1 mg/l to about 10 g/l.

### Claim 4 (depends on 1, 2)

The bath of claim 1 or 2 wherein said brightening additive is present in an amount of from about 0.015 g/l to about 2 g/l.

### Claim 5 (depends on 1, 2)

The bath of claim 1 or 2 wherein said bath has a pH of from about 0 to about 6.

### Claim 6 (depends on 1, 2)

The bath of claim 1 or 2 wherein said bath has a pH of from about 9 to about 14.

### Claim 7 (depends on 1, 2)

The bath of claim 1 or 2 wherein said bath has a pH of from about 6 to about 9 and contains chelating agents to keep the zinc ions in solution.

### Claim 8

A process for electroplating a zinc deposit onto a substrate comprising electrodepositing zinc from a conductive aqueous solution containing zinc ions and a brightening amount of a water soluble brightening additive selected from the group consisting of a monomer of the following general formula and polymers thereof: ##STR13## wherein: n is from 1 to about 6;
Y is --OX, --NX.sub.2, --SO.sub.3 H, --SO.sub.3 M, --COOH, --COOM, --SX, or --CN;
X is H, or an alkanol, alkamine, sulfoalkyl, carboxyalkyl, hydroxyaryl, sulfoaryl, carboxyaryl, or aminoaryl having from 1 to about 10 carbon atoms;
M is H, Li, Na, K, Be, Mg or Ca;
Q is --OR.sub.4, --N(R.sub.4).sub.2, --OZ, --OM, or halogen;
Z is an aryl group or a substituted aryl group having from about 6 to about 14 carbon atoms;
R.sub.1 is H or an alkyl group having from 1 to about 4 carbon atoms;
R.sub.2 is H or an alkyl, alkanol, or alkamine group having from 1 to about 4 carbon atoms, or ##STR14## R.sub.3 is H or an alkyl group having from 1 to about 4 carbon atoms, phenyl, substituted-phenyl, or ##STR15## R.sub.4 is H or an alkyl, alkenyl, alkynyl, alkanol, alkenol, alkynol, keto alkyl, keto alkynyl, keto alkenyl, alkamine, alkoxy, polyalkoxyl, sulfoalkyl, carboxyalkyl, mercapto alkyl, or nitriloalkyl group having from 1 to about 12 carbon atoms, phenyl or substituted phenyl or ##STR16## R.sub.5 is H, --OH, or a hydroxyalkyl group having from 1 to about 4 carbon atoms;
r is 1 to about 3;
and mixtures thereof.

### Claim 9 (depends on 8)

The process of claim 8 wherein said brightening additive is selected from the group consisting of:
Poly[N-(2-hydroxyethyl) nitrilo di-(ethylpropionate)];
Poly[N-(2-hydroxyethyl) nitrilo di-(N'-(2-hydroxyethyl) propionamide];
Poly[N-(2-hydroxyethyl)-N-(2-cyanoethyl)-.beta.-amino propionic acid];
Tetra[N-methyl N-cyanomethyl .beta.-amino propionate] pentaerythritol;
Poly[N-(hydroxy tert-butyl).beta.-amino .beta.-methylcarboxy methyl propionate];
Poly[N-(2-hydroxypropyl).beta.-amino-.alpha.-methyl aceto methyl propionate];
Poly[N-(2-hydroxyethyl).beta.-amino-.alpha.-phenyl methyl propionate];
Poly[.beta.-tauryl ethyl propionate];
Poly[N,N-di(2-hydroxyethyl)nitrilo .beta.-methyl propionamide];
Poly[N-(3-hydroxypropyl).beta.-aminopropionamide-(N'-isopropyl-sodium sulfonate];
Poly[N-(2-mercaptoethyl) nitrilo di(methyl propionate)];
Poly[N-(2-carboxyethyl).beta.-amine di(butyl propionate)];
Poly[N-(hydroxyethyl aminoethyl).beta.-amino(2-methoxyethyl) propionate];
Poly[N-(2-hydroxyethyl) nitrilo di-(2-ethyl hexyl propionate)];
N-(2-hydroxypropyl) nitrilo di-(polyethoxy propionate) where the molecular weight of the polyether group is 2000-4000;
Tetra[N-2-hydroxyethyl)-.beta.-amino propionate] pentaerythritol;
and mixtures thereof.

### Claim 10 (depends on 8, 9)

The process of claim 8 or 9 wherein said brightening additive is present in an amount of from about 0.1 mg/l to about 10 g/l.

### Claim 11 (depends on 8, 9)

The process of claim 8 or 9 wherein said brightening additive is present in an amount of from about 0.015 g/l to about 2 g/l.

### Claim 12 (depends on 8, 9)

The process of claim 8 or 9 wherein said bath has a pH of from about 0 to about 6.

### Claim 13 (depends on 8, 9)

The process of claim 8 or 9 wherein said bath has a pH of from about 9 to about 14.

### Claim 14 (depends on 8, 9)

The process of claim 8 or 9 wherein said bath has a pH of from about 6 to about 9 and contains a chelating agent in an amount effective to keep zinc ions in solution.

### Claim 15 (depends on 8, 9)

The process of claim 8 or 9 wherein said electrodepositing is carried out at a high cathode current density of from about 100 to about 10,000 ASF.

### Claim 16 (depends on 8, 9)

The process of claim 8 or 9 wherein said bath has a pH of from about 0 to about 6 and said electrodepositing is carried out at a high cathode current density of from about 100 to about 10,000 ASF.