Note: Descriptions are shown in the official language in which they were submitted.
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PROD~CTION OF NICXELIZED ARTICLES
The present inYention relates to an Lmproved
process for producing nickelized articles by el~ctro-
deposition of nicXel from aqueous acidic baths containing
as essential constituents one or more nickel salts, one
or more inorganic acids and one or more brighteners, some
of these brighteners heing novel compounds. The present
invention further relates to a brightener mixture useable
for this purpose.
It is known that acidic nickel electrolytes must
contain low level~ of organic substances if the electro-
deposition of nickel is to produce a bright, ductile and
planar coat of the metal. Such brighteners, which are
generally s~bdivided into prLmary brighteners and second-
ary brighteners, are customarily used in the form of
co~binations of pluralities of brighteners, in order to
increase the effect. None the less, the brightness
obtained in this way is still in need of improvement.
DE-B 11 91 652 (1) describes monocyclic or
polycyclic heterocyclic nitrogen bases of the aromatic
type in quaternized form such as pyridinium salts, eg.
2-pyridinium-1-sulfatoethane, for use as planarizers, ie.
brighteners, for acidic electronickelizing baths. These
compounds are used together with c:ustomary brighteners
such a8 benzene-m-disulfonic acid, diaryldisulfimides or
sulfonamide~.
The monogxaph, Praktische GalvanotechniX, Eugen
G. Lenze Verlag, Saulgau, 4th edi~ion 1984, pages 268 to
271 (2) describe~ classss of customary brighteners for
nickel electxolytes. Although the substance in que5tion
are divided into primary and secondary brightener and
planarizers, there is an admission that clear-cut
classification is no~ always possible. The brightness-
producing substances mentioned are:
- sulfonLmides, eg. benzosulfimide
- sulfonamides
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- benzenesulfonic acids, eg. mono-, di- and tri-
ben~en~sulfonic acid
- naphthalenesulfonic acids, eg. mono-, di- and tri-
naphthalenesulfonic acid
~ alkanesulfonic acids
- sulfinic acid
- sulfonated arenesulfones
- aliphatic compounds with double and/or triple bonds,
eg. butynediol0 - monocyclic and polycyclic nitrogen-containing
heterocycles which may additionally contain further
hetero atoms such a sulfur or selenium
- coumarin
- amines and quaternary ammonium compounds as planar-
izers
- sucrose.
The brighteners customarily used in practice are
alkenylsulfonic acids such a~ sodium vinylsulfonate or
so~ium allylsulfonate combined with other brighteners
such as proparsyl alcohol, 2-but~ne-1,4-diol, propyne~
sulfonic acid or 2-pyridinium-1-sulfatoethane.
It is an ob~ect of the present invention to
provide an improved proc~s3 for producing nickelized
articles of higher brightness but e~ually good ductility
and surface planarity.
We have found that this ob~ect i~ achieved by a
process for producing nickelized articles by electro-
deposition of nickel from an aqueous acidic bath contain-
ing a3 essential constituents one or mor~ nickel salts,
one or more inorganic acids and one or more brighteners,
which comprise~ using as brightener a 2-hydroxy-
3 butenyl-con~aining compound of the formula I
(CH2=cH-lH-cH2-)~ I
OH
~laSi;~5~
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where n is 1l 2 or 3 and the variable A has the following
meanings:
for n = 1
- hydroxyl
- a group of the formula -ORl, where Rl is Cl-C4-alkyl,
which may be sulfo-substituted, phenyl, 3- or
4-sulfophenyl, ~- or ~-naphthyl, 3-, 4-, 5-, 6- or
7-sulfo-~-naphthyl or 4-, 5-, 6-, 7- or 8-sulfo-
~-naphthyl0 - a phosphorus-containing group of -O-PO(OX)H Qr
-O-PO ( OX ) 2 r where X is hydrogen or an alXali metal
or ammonium cation
- a sulfo group of the formula -S03X
- an amino group of the formula -NH2, -NHRl or -N(Rl)2,
where if two radicals R1 are present on the N-atom
they can be identical or diferen~
for n = 2
- an amino group of the formula -NH- or -NRl-
- a trivalent oxygen atom
for n = 3
- a trivalent nitrogen atom.
Cl-C4-al~yl R1 which may ladditionally carry a
sulfo group i~ in particular mathyl, ethyl, n-propyl,
isopropyl, n-butyl, isobutyl, selc-butyl 9 tert~butyl,
sulfomethyl, 2-sulfoethyl, 3-sulfopropyl or 4-sulfobutyl,
the sulfo group being usually in the form of the free
acidr in the form of an alkali metal salt, in particular
the sodium or potassium salt, or in the form of the
ammonium salt. Particularly good results are obtained
with 2 sulfoethyl.
A compound I with a phosphorus-containing group
of the formula -O-POtOX)H is a phosphorous monoester or
a salt thereof and a compound I with a phosphorus-con-
taining group of the formula -O-PO(OX~2 is a phosphoric
monoester or a salt thereof.
The variable X is hydrogen or an alkali metal
cation, in particular sodium or potassium, or an ammonium
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cation. Since the compounds I are used according to the
present invention in an acidic medium, in particular in
a weakly acidic medium, there is of course an equilibrium
between the alkali metal or ammonium salts and the
corresponding free acids.
In a preferred embodiment of the invention, the
compound I used has n equal to 1 or 3 and ~ ~ariable
with the following meanings:
for n = 1
- hydroxyl
- a group of the formula -oR2, where R2 is 2-sulfo-
ethyl, 3-sulfophenyl or 4~sulfophenyl
a sulfo group of the formula -S03X
- an amino group of the formula -NHR2
for n = 3
- a trivalent nitrogen atom~
The present invention further provides novel
2-h~droxy-3-butenyl~containing compounds of the formula
Ia
(CH2=C~ cH-cH2-)nB Ia
OH
where n is 1~ 2 or 3 and the variable B has the following
meanings t
where n = 1
- a group of th~ formula -oR3, where R3 i8 Cl-c4-alkyl,
which is additionally ~ulfo-substituted, 3- or
4-~ulophenyl, ~- or ~-naphthyl, 3-, 4-, 5-, 6- or
7-sulfo ~-naphthyl or 4-~ 5-, 6-, 7- or 8-sulfo-
~-naphthyl
- a phosphorus-containing group of -O-PO(OX)H or
-O-PO(OX)2, where X is hydrogen or an alkali metal
or ammonium cation
- an amino group of the formula -NHR3
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- an amino group of the formula -N(R4)2 possessing two
identical radicals R4, where R4 is R3 or phenyl
for n = 2
- an amino group of the formula -NH-
- an amino group of the formula -NR3-
for n = 3
- a tri~alent nitrogen atom.
A Cl-C4-al~yl R3 which additionally carries a
sulfo group is in particular sulfomethyl, 2-sulfoethyl,
3-sulfopropyl or 4-~ulfobutyl, the sulfo group usually
being in the form of the free acid, in the form of an
alkali metal salt, in particular the sodium or po~assium
salt, or in the form of the ammonium salt.
The compounds I and Ia are advantageously pre-
pared by reacting vinyloxirane, 4-chloro-3-hydroxy-
l-butene or 4-bromo-3-hydroxy-l~butene in the right
molar ratio with reactants containing the right nucleo-
philic groups. Such reactants are for example:
- water
_ C1-C4 alkanols
- salts of hydroxymethanesulfonic acid, 2-hydroxy-
ethane~ulfonic acid (isethiollic acid), 3-hydroxy-
propanesulfonic acid or 4-hydroxybutanesulfonic acid
- phenol and ~- or ~-naphthol
- sal~s of 3- or 4-sulfoph~enyl and 3-, 4-, 5-, 6- or
7-~ulfO-a-naphthol or 4-, 5-, 6-, 7- or ~ sulfo-
~naphthol
- phosphorous acid or hydrogen phosphites
- phosphoric acid or hydrogen or dihydrogen phosphates
- ~ulfurous acid or hydrogen sulfites
ammonia
- mono- or dialkylamines ha~ing from 1 ~o 4 carbon
atoms per alkyl group
- salts o~ aminomsthan2sulfonic acid, 2-aminoethane-
sulfonic acid (taurine), 3-aminopropanesulfonic acid
or 4~aminobutanesulfonic acid
aniline and a- or ~-naphthylamine
.
5~
~ 6 ~ O.Z. 0050/42002
- metanilic acid or sulfanilic acid and 3-, 4-, 5-, 6-
or 7-sulfo-~-naphthylamine or 4-, 5-, 6-, 7- or
8-sulfo-~-naphthylamine and salts thereof.
The reaction is in general carried out under
S conditions customary for epoxides and halohydrins, as
described for example in M.S. Malinovskii, Epoxides and
their Deri~atives, Israel Program for Scientific Transla-
tions, Jerusalem, 1965, or Houben-Weyl, Methoden der
Organischen Chemie, volume VI/3 (Oxygen compounds I,
Part 3), Thieme Verlag Stuttgart, 13650
In a preferred embodiment o the invention, the
compounds I are used together with at least one further
brightener. Since the compounds I predominantly act as
primary brighteners, their combination with secondary
brighteners such as propargyl alcohol, 2 butyne-1,4-diol,
propynesulfonic aoid or preferably a monocyclic or poly-
cyclic heterocyclic nitrogen base of the aromatic type in
quaternized form, eg. 2-pyridinium-1-sulfatoethane,
produces particularly high brightness. However, it is
also possible to detect an increased offect with certain
primary brighteners such as ~ucrose.
The aqueou acidic nickel electrolyte baths used
contain one or usually more than one nickel salt, eg.
nickel sulfate and nickel chloride, one or more inorganic
acids, preferably boric acid and sulfuric acid,
brightener compounds I alone or preferably combined with
further, cu~tomary brighteners and optionally further
customary assistant~ and additiYe~ in the concentrations
cu~toma~y for this purpose, for example wetting agents
and pore inhibitors. Cu3tomary aqueous acidic nickel
electrolytes (Watts electrolytes) have the follow.ing
basic composition:
from 200 to 350 gJl of NiSO4 x 7 H2O
from 30 to 150 g/l of NiC12 x 6 H2O
from 30 to 50 g/l of H3BO3.
The pH of the electrolyte bath is customarily
within the range o~ from 3 to 6, preferably within the
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range of from 4 to 5. This pH is advantageously set with
a strong mineral acid, preferably sulfuric acid.
The compounds I are generally present in the
electrolyte baths in concentrations within the range of
from 0.1 to 2.0 g/l, preferably ~ithin the range of from
O.2 to 1.3 g/l. The concentrations of further, customary
brigh~eners are normally likewise within the range of
from 0.1 to 2.0 g/l.
The nickel electrolyte baths described can be
used to produce in particular nickel coatings on steel
articles, but also on articles made o~ other materials,
for example brass, which have been pretreated in a
conv~ntional manner, by electrocoating. This is in
general done at from 30 to 80C, preferably at from 40 to
60C.
The present invention further provides a
brightener mixture for aqueous acidic electronickelizing
baths which contain as essential constituents the com-
pounds I and monocyclic or polycyclic heterocyclic
nitrogen bases of the aromatic type in quaternized form
in the abovemen~ioned concentratiorls.
The compounds I used according to the present
invention are noteworthy for extremely high brightness
formation. They produce higher brightness than customary
brighteners, in some instances eve:n at lower concentra-
tion~ in the nickel electrolyte baths.
PREPARATION EXAMPLES 1 TO 6
EXANPLE 1
Preparation of 1,2-dihydroxy-3-butene
32.7 g of vinylQxirane, 70 g of water and 0.5 g
of 96% strength by weight sulfuric acid as catalyst was
stirred at 85-90C for 5 hour~. The sulfuric acid was
then neutralized with 50~ streng~h by weight sodium
hydroxide solution. Small amounts of unconverted vinyl-
oxirane were distilled off at 50C under a water jet
vacuum together with excess water, leaving behind 40 g of
product in the form of a viscous liquid.
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EXAMPLE 2
Preparation of sodium 4-(2'-hydroxy-3' buten~ yloxy)-
benæenesulfonate
267.7 g of 65% strength by weight p-phenol-
sulfonic acid w~re diluted with lO0 g of water and
admixed with 80 g of 50% strength by weight sodium
hydroxide solution. Then 70 g of vinyloxirane were added
dropwise at 70-80C with stirring in the course of
30 minutes. The mixture was subsequently stirred at the
same temperature for 8 hours. The water was then removed
under a water jet vacuum, leaving behind 195 g of
product. The product was again taken up in water and
adjusted to a concentration o 50~ by weight.
EXAMPLE 3
Prepara~ion of sodium 2-hydroxy-3-butenesulfonate
21.5 g of vinylo~irane were added dropwise at
80C with stirring to a mixture of 80.4 g of 39% strength
by weight aqueous sodium hydxogen sulfite solution and
23.b g of water in the course of 20 minutes. The mixture
wa then ~tirred at the same temperatura for 8 hours.
Small amount~ of unconverted vinyloxirane and the water
were removed under a water jet vacuum, leaving behind
40 g of product. The product wa~ taken up in water and
adjusted to a concentration of 50~ by weight.
EXAMPLE 4
Preparation of tris(2-hydroxy-3-buten-1-yl)amine
126 g of vinyloxirane were added at 70-80C with
skirring to a mixture of 40.8 g of 25~ strength by weight
aqueou~ ammonia and 170 g of water in the course of 20
minutes. The mixture wa~ subseguently ~tirred at the same
tempera~ure for 5 hours. It was then reduced under a
water jet vacuum to 172 g. This left a viscous liguid
having a product content of 78~ by weight.
EXAMPLE 5
Preparation of sodium ~-N-12'-hydroxy-3'-buten~ yl)-
aminoethanesulfonate
70 g of vinyloxirane were added dropwise at
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70-`80C with stirring to 313 g of a 47% strength by
weight aqueous solution of the sodium salt of 2-amino-
ethanesul~onic acid (taurine) in the course of 30
minutes. The mixture was subsequently stirred at the same
temperature for 6 hours. The water was then removed under
a water jet vacuum. This left 218 g of product. The
product was taken up again in water, the solution being
adjusted to a product content of 50% by weight.
EXAMPLE 6
Preparation of sodium 2-N,N-bis(2'-hydroxy-3'-buten-
1'-yl)aminoethanesulfonate
Example 5 was repeated with twice the amount of
vinyloxirane, affording, after the reac~ion had taken
place and the reaction mixture had been concentrated
under a water ~et vacuum, 287 g of a product which was
taken up again in water, the solution being adjusted to
a product content of 50% by weight.
EXAMPLE 7
Preparation of sodium 4-N-(2'-hydroxy-3'-buten-l'-yl)-
aminobenzenesulfonate
70 g of vinyloxirane were added dropwise at
70-80C with stirring to a mixture of 173 g of 4-amino-
benzenesulfonic acid (sulfanilic acid), 200 g of water
and 80 g of 50% strength by weight aqueous sodium
hydroxide solution over 30 minutes. The mixture was
subsequently stirred at the same temperature for 4 hours,
giving 520 g of a ~olution having a product content of
53% by weight.
APPLIC~TION EXAMP1ES 8 TO 14 AND
3 0 COMPARATIVE EXA~LES A AND B
The products prepared in Ex~mples 1 to 7 were
used as brighteners in weakly acidic electronickelizing
baths.
The aqueous nickel electrolyte used had the
following composition:
300 gJl of NiSO4 x 7 HzO
60 g/l of NiCl2 x 6 H2O
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45 g/l of H3~03
2 g~l of sucrose
O.3 g/l of 2-pyridinium~ ulfa~oethane
X g/l of brightener as per table
0.5 gJl of a fatty alcohol derivative of the formula
C12H25/cl4H29-o-(cH2cH2o)2-so3Na as wetting agent
The pH of khe electrolyte was adjustPd with
sulfuric acid to 4.2.
The articles to be nickelized were brass panels
which, prior to being plated with nickel, were cathodic-
ally degreased in an alkaline ~lectrolyte in a conven-
tional manner. The nickelization took place in a 250 ml
Hull cell at 55C and a current strength of 2A for a
period of 10 minutes. The panel~ were th~n rinsed with
water and dried with compressed air.
The table below shows the results of these
experLments. It can be seen that the brighteners or
brightener mixtures used according to the presen~ inven-
tion produce a higher brightness than the prior art
agents t in some instances even at a lower concentration
in the nickel electrolyte baths~
TABLE
Test results of electrodeposition of nickel
Example Brightener of Concent:ration Brightness
No. Exampl~ No. X [gtll [rating3
~ . . _ , . .
8 1 0.3 4-5
9 2 0.8 4-5
3 0.~ 4-5
11 4 0~3 5
12 5 0.6 5
13 6 D.8 5
14 7 1.2 4-5
for comparison-
A sodium vinylsulfonate 0.8 4
B sod~um allyl~ulfonate 0.7 4
.
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Ratings scheme for brightness:
S = excellent (perfect specular gloss)
4 = good (almost specular gloss)
3 = moderate
2 = poor
1 = no brigh~ness
The ductility was very good with all examples
No. 8 to 14 and the comparative specimens A and B.
Except in the case of Example 8, where a trace of
overinhibition was found, it was impossible to detect any
interference with the nickel deposition process.
t
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