Electrodeposition of zinc and additive therefore

Claim 2

In an aqueous alkaline, cyanide-free zinc electroplating bath containing zinc ions and hydroxyl ions, the improvement comprising: including in said bath an effective brightening amount of at least one linear polyamine obtained by condensing a diamine of the formula: ##STR4## where R 1 , R 2 , R 3 and R 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 dihalide of the formula X -- (CH.sub.2).sub.n -- Y -- (CH.sub.2).sub.p -- X (II) where X represents a halogen atom, Y represents an oxygen atom, an ethynylene group (--C═C--), an ethenylene group (--HC═CH--), or a group ##STR5## where Z represents a hydrogen atom or an alkyl group with 1 to 4 carbon atoms and n and p, which may be the same or different, are zero or an integer from 1 to 5.

Claim 3

A bath according to claim 1 in which the linear polyamine is the condensate of a dihalide of formula (II) selected from the group consisting of 1,2-dibromoethane, 1,2-dibromoethylene, 1,3-dibromobutane, 1,4-dibromobutane, 1,6-dibromohexane, 1,2-dibromopropane, 1,3-dibromomopropane, 1,4-dibromobut-2-yne, 1,2-dichlorobutane, 1,3-dichlorobutane, 1,4-dichlorobutane, 1,3-dichloro-2-butene, 1,4-dichloro-2-butyne, 1,2-dichloroethane, 1,2-dichloroethylene, 1,6-dichlorohexane, 1,2-dichloropropane, 1,3-dichloropropane, di-(2-chloroethyl) ether, 1,2-diiodoethane, 1,3-diiodopropane and 1,4-diiodobutane.

Claim 4

A bath according to claim 1 in which the linear polyamine is the condensate of a diamine of formula (I) selected from the group consisting of 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 3-methylaminopropylamine, 3-cyclohexylaminopropylamine N,N'-diethyl-ethylenediamine, N,N'-dimethyl-ethylenediamine, 3-dimethylamino-propylamine, 3-diethylamino-propylamine, 4-diethylamino-butylamine, 2-dimethylamino-ethylamine, 2-diethylamino-ethylamine, N,N,N'-trimethyl-ethylene diamine, N,N,N'-triethyl-ethylene diamine and N,N,N',N'-tetramethyl-1,2-diamino-ethane.

Claim 5

A bath according to claim 1 in which the linear polyamine is the condensate of a diamine selected from the group consisting of 3-dimethylaminopropylamine, N,N,N',N'-tetramethyl-1,2-diaminoethane, N,N-dimethyl-N'-ethyl-ethylenediamine, N,N,N'-trimethyl-ethylenediamine and 3-methylaminopropylamine, and a dihalide selected from the group consisting of 1,3-dibromopropane, 1,2-dibromoethane, and di-(2-chloroethyl) ether.

Claim 6

A bath according to claim 1 in which the linear polyamine is a condensate of a diamine and a dihalide in a molar ratio of from 2:1 to 1:2.

Claim 7

A bath according to claim 1 containing 0.01 to 100 g/liter of the linear polyamine.

Claim 8

A bath according to claim 6 containing 0.1 to 10 g/liter of the linear polyamine.

Claim 9

In an aqueous alkaline, cyanide-free zinc electroplating bath containing zinc ions and hydroxyl ions, the improvement comprising: including in said bath an effective brightening amount of a. at least one linear polyamine obtained by condensing a diamine of the formula: ##STR6## where R 1 , R 2 , R 3 and R 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 dihalide of the formula X -- (CH.sub.2).sub.n -- Y -- (CH.sub.2).sub.p -- X (II) where X represents a halogen atom, Y represents an oxygen atom, an ethynylene group (--C═C--), an ethenylene group (--HC═CH--), or a group ##STR7## where Z represents a hydrogen atom, an alkyl group with 1 to 4 carbon atoms or a hydroxy group, and n and p, which may be the same of different, are zero or an integer from 1 to 5; provided that when Z represents a hydroxy group and n and p are both 1, R 1 and R 2 in formula (I) both represent hydrogen atoms; together with b. at least one of a pyridine compound of formula IIIa or a pyridine compound having a cation of formula III (b) ##STR8## where R 5 represents a hydrogen atom or an alkyl group with 1 to 5 carbon atoms; and R 6 represents a cyano group, a group -COOR 7 where R 7 represents a hydrogen atom, an alkali metal cation or an alkyl group with 1 to 5 carbon atoms; or a group --CONR 8 R 9 where R 8 and R 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 10 represents a radical selected from the group consisting of aralkyl, alkyl, alkenyl, esterified carboxyalkyl and hydroxyalkyl groups.

Claim 10

In an aqueous alkaline, cyanide-free zinc electroplating bath containing zinc ions and hydroxyl ions, the improvement comprising: including in said bath an effective brightening amount of a. at least one linear polyamine obtained by condensing a diamine of the formula: ##STR6## where R 1 , R 2 , R 3 and R 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 dihalide of the formula X -- (CH.sub.2).sub.n -- Y -- (CH.sub.2).sub.p -- X (II) where X represents a halogen atom, Y represents an oxygen atom, an ethynylene group (--C═C--), an ethenylene group (--HC═CH--), or a group ##STR7## where Z represents a hydrogen atom, an alkyl group with 1 to 4 carbon atoms or a hydroxy group, and n and p, which may be the same of different, are zero or an integer from 1 to 5; provided that when Z represents a hydroxy group and n and p are both 1, R 1 and R 2 in formula (I) both represent hydrogen atoms; together with b. at least one of a pyridine compound of formula IIIa or a pyridine compound having a cation of formula III (b) ##STR8## where R 5 represents a hydrogen atom or an alkyl group with 1 to 5 carbon atoms; and R 6 represents a cyano group, a group -COOR 7 where R 7 represents a hydrogen atom, an alkali metal cation or an alkyl group with 1 to 5 carbon atoms; or a group --CONR 8 R 9 where R 8 and R 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 10 represents a radical selected from the group consisting of aralkyl, alkyl, alkenyl, esterified carboxyalkyl and hydroxyalkyl groups.

Claim 11

A bath according to claim 8 in which a pyridine compound is used in which R 6 is in the 3- position.

Claim 12

A bath according to claim 8 in which the pyridine compound is selected from the group consisting of nicotinic acid, nicotinamide, N,N-diethyl-nicotinamide, 3-cyanopyridine, 4-cyanopyridine, methyl nicotinate, ethyl nicotinate, isonicotinic acid, 2-picolinic acid and butyl nicotinate and quaternised derivatives thereof.

Claim 13

A bath according to claim 10 in which the pyridine compound is quaternised by a radical selected from the group consisting of benzyl, ethoxycarbonylmethyl, propyl, allyl, ethyl, 2-hydroxyethyl, 2-ethoxycarbon-ylethyl and 2-hydroxypropyl groups.

Claim 14

A bath according to claim 11 containing nicotinic acid or a salt thereof quaternised by a benzyl, allyl, or 2-ethoxycarbonylmethyl group.

Claim 15

A bath according to claim 8 containing 0.01 to 50 g/liter of the pyridine compound.

Claim 16

A bath according to claim 13 containing 0.1 to 5 g/liter of the pyridine compound.

Claim 17

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: ##STR9## where R 1 , R 2 , R 3 and R 4 , which may be the same or different, each represents a hydrogen atom or an alkyl group with 1 to 4 carbon atoms, and where m is an integer from 1 to 5, with an alkyl dihalide of the formula X -- (CH.sub.2).sub.n -- Y -- (CH.sub.2).sub.p -- X (II) where X represents a halogen atom; Y represents an oxygen atom, an ethynylene group (--C═C--), an ethenylene group (--HC═CH--), or a group ##STR10## where Z represents a hydrogen atom, an alkyl group with 1 to 4 carbon atoms or a hydroxy group, and n and p, which may be the same different, are zero or an integer from 1 to 5; provided that when Z represents a hydroxy group, n and p are both 1 and R 1 and R 2 in formula (I) both represent hydrogen atoms; and b. at least one of a pyridine compound of formula IIIa or a pyridine compound having a cation of formula IIIb ##STR11## where R 5 represents a hydrogen atom or an alkyl group with 1 to 5 carbon atoms; and R 6 represents a cyano group, a group -COOR 7 where R 7 represents a hydrogen atom, an alkali metal cation or an alkyl group with 1 to 5 carbon atoms; or a group CONR 8 R 9 where R 8 and R 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 10 represents an aralkyl, alkyl, alkenyl, esterified carboxyalkyl or hydroxyalkyl group.

Claim 18

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: ##STR9## where R 1 , R 2 , R 3 and R 4 , which may be the same or different, each represents a hydrogen atom or an alkyl group with 1 to 4 carbon atoms, and where m is an integer from 1 to 5, with an alkyl dihalide of the formula X -- (CH.sub.2).sub.n -- Y -- (CH.sub.2).sub.p -- X (II) where X represents a halogen atom; Y represents an oxygen atom, an ethynylene group (--C═C--), an ethenylene group (--HC═CH--), or a group ##STR10## where Z represents a hydrogen atom, an alkyl group with 1 to 4 carbon atoms or a hydroxy group, and n and p, which may be the same different, are zero or an integer from 1 to 5; provided that when Z represents a hydroxy group, n and p are both 1 and R 1 and R 2 in formula (I) both represent hydrogen atoms; and b. at least one of a pyridine compound of formula IIIa or a pyridine compound having a cation of formula IIIb ##STR11## where R 5 represents a hydrogen atom or an alkyl group with 1 to 5 carbon atoms; and R 6 represents a cyano group, a group -COOR 7 where R 7 represents a hydrogen atom, an alkali metal cation or an alkyl group with 1 to 5 carbon atoms; or a group CONR 8 R 9 where R 8 and R 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 10 represents an aralkyl, alkyl, alkenyl, esterified carboxyalkyl or hydroxyalkyl group.

Claim 19

A composition according to claim 15 in which a pyridine compound is used in which R 6 is in the 3- position.

Claim 20

A composition according to claim 16 in which the pyridine compound is selected from nicotinic acid, nicotinamide N,N-diethyl-nicotinamide, 3-cyanopyridine, 4-cyanopyridine, methyl nicotinate, ethyl nicotinate, isonicotinic acid, 2-picolinic acid and butyl nicotinate and quaternised derivatives thereof.

Claim 21

A composition according to claim 17 in which the pyridine compound is quaternised by a group selected from benzyl, ethoxycarbonylmethyl, propyl, allyl, ethyl, 2-hydroxyethyl, 2-ethoxycarbonylethyl and 2-hydroxypropyl groups.

Claim 22

A composition according to claim 18 containing nicotinic acid or a salt thereof quaternised by a benzyl, allyl, or 2-ethoxycarbonylmethyl group.

Claim 23

A composition according to claim 15 in which the linear polyamine is the condensate of a diamine of formula (I) selected from 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 3-methylaminopropylamine, 3-cyclohexylaminopropylamine, N,N'-diethyl-ethylenediamine, N,N'-dimethyl-ethylenediamine, 3-dimethylamino-propylamine, 3-diethylamino-propylamine, 4-diethylamino-butylamine, 2-dimethylamino-ethylamine, 2-diethylamino-ethylamine, N,N,N'-trimethyl-ethylene diamine, N,N,N'-triethyl-ethylene diamine and N,N,N'N'-tetramethyl-1,2-diamino-ethane.

Claim 24

A composition according to claim 15 in which the linear polyamine is the condensate of a dihalide of formula (II) selected from 1,2-dibromoethane, 1,2-dibromoethylene 1,3-drbromobutane, 1,4-dibromobutane, 1,4-dibromobutan-2-ol, 1,6-dibromohexane, 1,2-dibromopropane, 1,3-dibromopropane, 1,3-dibromopropan-2-ol, 1,4-dibromobut-2-yne, 1,2-dichlorobutane, 1,3-dichlorobutane, 1,4-dichlorobutane, 1,3-dichloro-2-butene, 1,4-dichloro-2-butyne, 1,2-dichloroethane, 1,2-dichloroethylene, 1,6-dichlorohexane, 1,2-dichloropropane, 1,3-dichloropropane, 1,3-dichloropropan-2-ol, di-(2-chloroethyl) ether, 1,2-diiodoethane, 1,3-diiodopropane and 1,4-diiodobutane.

Claim 25

A composition according to claim 15 in which the linear polyamine is the condensate of a diamine selected from 3-dimethylaminopropylamine, N,N,N',N'-tetramethyl-1,2-and a diaminoethane, N,N-dimethyl-N'-ethyl-ethylenediamine, N,N,N'-trimethyl-ethylenediamine and 3-methtlaminopropylamine, and a dihalide selected from 1,3-dibromopropane, 1,2-dibromoethane, and di-(2-chloroethyl) ether.

Claim 26

A composition according to claim 15 in which the linear polyamine is a condensate of a diamine and a dihalide in a molar ratio of from 2:1 to 1:2.

Claim 27

A composition according to claim 15 in which component (a) and component (b) are present in a ratio of from 2:1 to 1:2.