Note: Descriptions are shown in the official language in which they were submitted.
Z~ 6
IELD OF THE INVENTION
The present invention relates to novel stabilizers
for bleaching agents and to det:ergent compositions
containing the same~
BACKGRO~ND OF THE INVENTIpN
Bleaching agents have long been used in laundry
detergents to enhance the overall cleaning action
thereof. Instability of bleaching agents in detergents
is mediated principally by metal ion contamination in
the detergent themselves, in the wash li~uors and in
the textiles and fabrics being cleaned. For example,
the hydrogen peroxide responsible for the bleaching
action in detergent formulas containing a peroxide-
based bleaching agent, acts by dissociating into
perhydroxyl ion:
HzO2 HOO ~ H
This ion attacks the conjugated double bonds which make
up most color causing organics or stairls. If metal
ions (e g CuII FeIII MnII) are present the perhydroxyl
ion reacts instead with the hydrogen peroxide causing
both species to degrade before they can remove stains.
As a result, bleach containing laundry detergents have
heretofore been made more ef~icient by the addition of
complexing agents which tie up transition metal ions
thus reducing the destructive degradation of the
bleaching component.
Examples of conventional acknowledged complexing
agents heretofor~ u~ed in detergents include
nitrilotriacetic acid (NTA), ethylenediaminetetraacetic
acid (EDTA), ethylenediaminetetramethylenephosphonic
acid (EDTMP), propylenediaminetetraacekic acid (PDTA),
hydroxypropylenediaminetetraacetic acid (HPDTA),
hydroxyethanediphosphonic acid,
diethylenetriamin~tetraacetic acid,
diethylenetriaminetetramethylenephosphonic acid,
hydroxyethylimino, diacetic acid,
hydroxyethylethylenediaminetriacetic acid
diethylenetriaminepentaacetic acid and also for sxample
diethanolglycine, ethanolglycine, citric acid,
glucoheptonic acid or tartaric acid, as ~ound for
example under the heading of Waschmittel in Ullmann's
Encyklopadie der technischen Chemie, 4th edition,
volume 2~, pages 63-160, in particular pages 91-96,
Verlag Chemie, Weinheim, 1983.
The action of the existing complexing agents, some
of which are used on a large scale, is not always
optimal to stabilize bleaching agents in detergent
compositions. For instance, NTA makes a very good
complexing agent and, in detergents, a fairly good
builder for improving the whitening effect and for
preventing deposits which cause incrustations and
graying on the fabric. However, its performancP as a
bleach stabilizer is comparatively poor. Even EDTA,
despite its good complexing action toward heavy
metals, is only a moderate bleach stabilizer in
detergents.
In mos~ cases, the biodegradability of prior art
complexing agents also leaves something to be desired.
For instance, EDTA turns out to be insufficiently
biodegradable in conventional tests, as do PDTA, HPDTA
and certain phosphonates which, furthermore, are
frequently undesirable on account of their phosphorus
content.
;3 ~
France Patent Application No. 1,338,856, patented
August 26, 1963 discloses perborate detergent
compositions for washing laundry in boiling water. The
detergent composition contains methyliminodiacetic acid
in association with a water-soluble copper salt to
enhance the whitening effects of the perborate
bleaching agant. This association forms a metal buffer
which maintains the amount of free copper present in
the washing medium at a value corresponding to the
maximum effect of the whitening efficiency of the
perborate. The patent does not d~sclose
alkyliminodiacetic acid for bleach stabilization in
detergent compositions.
It is an object of the present invention to
provide efficacious bleach stabilizers for detergents
which have good complexing properties, is ecologically
safe, ideally contains no phosphorus and is readily
biodegradable.
It is a related object of the invention to provide
~O a method of stabilizing bleaching agents in detergent
formulations by incorporating into said detergent
formulations an effective bleach stabilizing amount o~
a biodegradable nonphosphorus-containing bleach
stabili~er.
Further, it is an object of the invention to
provide improved detergent formulations containing the
biodegradable nonphosphorus-containing bleach
stabilizers of the invention.
Other important objects of this invention will
become apparent from the ensuing description and
appended claims.
q~ 6
SUMMARY OF THE INVENTION
We have found that the aforegoing objects are
achieved by employing as a bleach stabilizer in
detergent formulations, an effective bleach stabilizing
amount of an alkyliminodiacetic acid compound in which
the alkyl group has up to about 6 carbon atoms,
preferably about 1 to 4 carbon atoms. It is within the
scope of this invention that any alkyliminodiacetic
acid may be present in the form of its sodium,
potassium, ammonium or substituted ammonium salt.
The term "substituted ammonium" as used herein and
in the appended claims refers to an ammonium radical
substituted with one or more alkyl groups having from 1
to 4 carbon atoms.
Specific examples o~ stabilizers in accordance
with the invention include, for example,
methyliminodiacetic acid, ethyliminodiacetic acid,
propyliminodiacetic acid and the like.
Alkyliminodiacetic acids are available
commercially but may be prepared cheaply and easily by
the method for the preparation of methyliminodiacetic
acid as described by G. J. Berchet in Organic
Synthesis, Vol. 11, pages 397-398, which method is
described in Example I below.
Bleaching agents which may be stabilized in
accordance with the invention are, in particular,
hydrogen peroxide and derivatives thereof or available
chlorine compounds. Of the bleaching agent compounds
which provide H202 in water, sodium perborate hydrates,
such as NaBO2.H202.3H20 and NaBO2.H202, are of particular
importance. However, it is also possible to use other
H202-providing borates. ~hese compounds can be replaced
in part or in full by other sources of active oxygen,
in particular by peroxyhydrates, such as
peroxycarbonates, peroxyphosphonates, citrate
perhydrates t urea-H20~, or melamine-HzOz compounds and
also by H20z-providing peracid salts, for example
caroates, perbenzoates or peroxyphthalates.
Aside from stabilizers according to the invention,
customary water-soluble and/or water-insoluble
stabilizers for peroxy compounds can be incorporated
together with the former in amounts from 0.25 to 10% by
weight, based on the peroxy compound. Suitable water-
insoluble stabilizers are the magnesium silicates
MgO: Sio2 from 4:1 to 1:4, preferable from ~:1 to 1:2, in
particular 1:1, in composition usually obtained by
precipitation from aqueous solutions. In their place
it is also possible to use other alkaline earth metals
of corresponding composition.
To obtain a satisfactory bleaching action even in
washing below 80~C, in particular in the range from
60 to 40C, it is advantageous to incorporate bleach
activators in the detergent, advantageously in an
amount from 5 to 30% by weight, based on the H202
providing compound.
Activators for peroxy-compounds which provide Hz02
in water are certain N-acyl and O-acyl compounds, in
particular acetyl, propionyl or benzyl compounds, which
form organic peracids with H2O2 and also carbonic and
pyrocarbonic esters. Useful compounds are inter alia:
N-diacylated and N,N'-tetraacylated amines, e.g.
N,N,N',N'-tetraacetyl-methylenediamine or
-ethylenediamine, N,N~diacetylaniline and N,N-
diacetyl-p-toluidine, and 1,3-diacylated hydantoins,
alkyl-N-sulfonylcarboxamides, N-acylated cyclic
hydrazides, acylated triazoles or urazoles, e.g.
2~
monoacetylmaleohydrazide, 0,NjN-trisubstituted
hydroxylamines, e.g. O-benzoyl-N,N-
succinylhydroxylamine, O-acetyl-N,N-
succinylhydroxylamine, O-p-methoxybenzoyl-N,
N-succinylhydroxylamine, O-p-nitrobenzoyl-N,
N-succinylhydroxylamine and O,;N,N-
triacetylhydroxylamine, carboxylic anhydrides, e.g.
benzoic anhydride, m-chlorobenzoic anhydride, phthalic
anhydride and 4-chlorophthalic anhydride, sugar esters,
e.g. glucose pentaacetate, imidazolidine derivatives,
such as 1,3-diformyl-4,5-diacetoxyimidazolidine, 1,3-
diacetyl-4,5-diacetoxyimidazoline and 1,3-diacetyl-
4,5-dipropionyloxyimidazolidine, acylated
glycolurils,e.g. tetrapropionylglycoluril or
diacetyldibenzoylglycoluril, dialkylated 2,5-
diketopiperazines, e.g. 1,4-diacetyl-2,5-
diketopiperzine, 1,4-dipropionyl-2,5-diketopiperazine,
and 1,4-dipropionyl-3,6-dimethyl-2,5--diketopiperazine,
acetylation and benzoylation products of
propylenediurea or 2,2-dimethylpropylenediurea, the
sodium salt of p-(ethoxycarbonyloxy)benzoic acid and of
p-(propoxycarbonyloxy)benzenesulfonic acid and also the
sodium salts of alkylatad or acylated phenolsulfonic
esters, such as p-acetoxybenzenesulfonic acid, 2-
acetoxy-5-nonylbenzenesulfonic acid, 2 acetoxy-5-
propylbenzenesulfonic acid or of
isononanoyloxyphenylsulfonic acid.
The bleaching agents used can also be active
chlorine compounds of the inorganic or organic type.
Inorganic active chlorine compounds include alkali
metal hypochlorites which can be used in particular in
the form of their mixed salts and adducts on
orthophosphates or condensed phosphates, for example on
pyrophosphates and polyphosphates or on alkali metal
silicates. If the detergent contains monopersulfates
and chlorides, active chlorine will form in aqueous
solution.
Organic active chlorine compounds are in
particular the N-chlorine compounds where one or two
chlorine atoms are bonded to a nitrogen atom and where
preferably the third valence oE the nitrogen atom leads
to a negative group, in particular to a CO or SO2 group.
These compounds include dichlorocyanuric and
trichlorocyanuric acid and their salts, chlorinated
alkylguanides or alkylbiguanides, chlorinated
hydantoins and chlorinated melamines.
Bleaching stabilizers of the invention may be used
in detergent formulations in general in an amount from
about 0.01 to 10% by weight, preferably from 0.05 to 6%
by weight, most preferably 0.1 to 2.0% by weight, based
on the total weight of the detergent formulations.
The stabilizers according to the invention can
also be used in det~rgent formulations together with
other prior art constituents e.g. complexing agents,
builders, co-builders, surfactants, whiteners, etc., in
which case the general properties can be substantially
improved in respect of sequestration, incrustation
inhibition, grayness inhibition, primary washing action
and bleaching action.
Detergent formulations which, based on the total
weight, contain from 0.01 to 10%, preferably from 0.05
to 6.0%, by weight of a compound in accordance with the
invention generally contain as additional constituents,
based on the total weight, from 6 to 25% by weight of
surfactants, from 15 to 50% by weight of builders with
or without cobuilders, from 5 to 35%, typically 15 to
20%, by weight of bleaching agents, with or without
bleaching agent activators, and from 3 to 30~ by weight
of assistants, such as enzymes, foam regulants,
corrosion inhibitors, optical brighteners, scents, dyes
or formulation aids, e.g~ sodium sulfate.
Customary constituents of detergent formul~tions
referred to above in general terms are xecited in terms
of examples below:
Suitable surfactants are those which contain in
the molecule one or more hydrophobic organic radicals
and one or more water-solubilizing anionic,
zwitterionic or nonionic groups. The
hydrophobicradicals usually are aliphatic hydrocarbyl
of 8 to 26, preferably 10 to 22, in particular 12 to
18, carbon atoms or aromatic alkyl having 6 to 18,
preferably 8 to 16, aliphatic carbon atoms.
Suitable synthetic anionic surfactants are in
particular those of the sulfonate, sulfate or synthetic
carboxylate type.
Suitable surfactants of the sulfonate type are
alkylbenzenesulfonates having 4 to 15 carbon atoms in
the alkyl moiety, mixtures of alkene and hydroxyalkane-
sulfonates and also disulfonates as obtained for
example from monoolefins having a terminal or
nonterminal double bond by sulfonation with gaseous
sulfur trioxide and subsequent alkaline or acid
hydrolysis of the sulfonation products. Also suitable
are alkanesulfonates obtainable from alkanes by
sulfochlorination or sulfoxidation and subsequent
hydrolysis or neutralization or by bisulfite addition
onto olefins. Further useful surfactants of the
sulfonate type are the esters of alpha-sulfo fatty
acids, for example the alpha-sulfonic acids of
hydrogenated methyl or ethyl esters of coconut, palm
kernel or tallow fat acid.
Suitable surfactants of t:he sulfate kype are the
sulfuric monoesters of primary alcohols, for example
coconut fat alcohols, tallow fat alcohols or oleyl
alcohol, and those of secondary alcohols. Also
suitable are sulfated fatty ac:id alkanolamines, fatty
acid monoglycerides or reaction products of from 1 to 4
moles of ethylene oxide with primary or secondary fatty
alcohols or alkylphenols.
Further suitable anionic sur~actants are the fatty
acid esters or fatty amides of hydroxy- or amino-
carboxylic or sulfonic acids, for example the fatty
acid sarcosides, glycolates, lactates, taurides or
isothionates.
Anionic surfactants can be present in the form of
their sodium, potassium and ammonium salts and also as
soluble salts of organic bases, such as mono-, di-, or
triethanolamine. Also possible are ordinary soaps,
i.e. salts of natural fatty acids.
Suitable nonionic surfactants (nonionics) are for
example adducts of from 3 to 40, preferably 4 to 20,
moles of ethylene oxide on 1 mole of fatty alcohol,
al.kylphenol, fatty acid, fatty amine, fatty acid amide
or alkanesulfonamideO Of particular importance are the
adducts of from 5 to 16 moles of ethylene oxide on
coconut or tallow fat alcohols, on oleyl alcohol or on
synthetic alcohols of 8 to 18, preferably 12 to 18,
carbon atoms, and also on mono- or dialkylphenols of 6
to 14 carbon atoms in the alkyl(s). Besides these
water-soluble nonionics, however, it is also possible
to use water-insoluble or incompletely water-soluble
polyglycol ethers having 1 to 4 ethylene glycol ether
q~l~?~
radicals in the molecule, in particular if used
together with water-soluble nonionic or anionic
surfactants.
Further suitable nonionic- surfactants are the
water-soluble adducts of ethy].ene oxide on propylene
glycol ether, alkylenediaminoE~olypropylene glycol and
alkylpolypropylene glycol havi.ng 1 to 10 carbon atoms
in the alkyl chain which contain from 20 to 250
ethylene glycol ether groups and from 10 to 100
propylene glycol ether groups and where the
polypropylene glycol ether chain acts as a hydrophobic
radical.
It is also possible to use nonionic surfactants of
the amine oxide or sulfoxide type.
The foaming power of surfactants can be enhanced
or reduced by combining suitable types of surfactants.
A reduction can also be obtained by adding
nonsurfactant like organic substances.
Suitable builder substances are for example: wash
alkalis, such as sodium carbonate and sodium silicate,
or complexing agents, such as phosphates, or ion
exchangers, such as zeolites, and mixtures thereof.
These builder substances have as their function to
eliminate the hardness ions, which come partly from the
water, partly from dirt or the textile material, and to
support the surfactant action. Aside from the
abovementioned builder substances, the builder
component may further contain cobuilders. In modern
detergents, it is the function of cobuilders to
undertake some of the functions of phosphates, e.g.
sequestration, soil antiredeposition and primary and
secondary washing action.
'~?~
The builder components may contain for example
water-insoluble silicates as alescribed for example in
German Laid-Open Application DE-OS No. 2,412,837 and/or
phosphates. As a phosphate it is possible to use
pyrophosphate, triphosphate, hligher polyphosphates and
metaphosphates. Similarly, phosphorus-containing
organic complexing agents, such as alkanepolyphosphonic
acids, amino- and hydroxy alkanepolyphosphonic acids
and phosphonocarboxylic acids, are suitable for use as
further detergent ingredients. Examples of such
detergent additives are the following compounds:
methanediphosphonic acid, propane-1,2,3-triphosphonic
acid, butane 1,2,3,4-tetraphosphonic acid,
polyvinylphosphonic acid, 1-aminoethane-1,1-
diphosphonic acid, l--amino-l-phenyl-l,l-diphosphonic
acid, aminotrismethylenetriphosphonic acid,
methylamino- or ethylamino-bismethylenediphosphonic
acid, ethylenediaminetetramethylenetetraphosphonic
acid, diethylenetriaminopentamethylenepentaphosphonic
acid, 1-hydroxyethane-1,1-diphosphonic acid,
phosphonoacetic and phosphonopropionic acid, copolymers
of vinylphosphonic acid and acrylic and/or maleic acid
and also partially or completely nelltrali~ed salts
thereof.
Further organic compounds which act as comp~exing
agents for calcium and may be present in detergent
formulations are polycarboxylic acids,
hydroxycarboxylic acids and aminocarboxylic acids which
are usually used in the form of their water-soluble
salts.
Examples of polycarboxylic acids are dicarboxylic
acids of the general formula HOOC-(CH2)m-COOH where m is
0 8, and also maleic acid, methylenemalonic acid,
citraconic acid, mesaconic acid, ita~onic acid,
noncyclic polycarboxylic acids having 3 or more
carboxyl groups in the molecule, e.g. tricarballylic
acid, aconitic acid, ethylenetetracarboxylic acid,
1,1,3-propanetetracarboxylic acid, 1,1,3,3,5,5-
pentanehexacarboxylic acid, hexanehexacarboxylic acid,
cyclic di- or polycarboxylic acids, e.g.
cyclopentanetetracarboxylic acid,
cyclohexanehexacarboxylic acid,
tetrahydrofurantetracarboxylic acid, phthalic acid,
terephthalic acid, benzene-tricarboxylic,
-tetracarboxylic or-pentacarboxylic acid and mellitic
acid.
Examples of hydroxymonocarboxylic and
hydroxypolycarboxylic acids are glycollic acid, lactic
acid, malic acid, tartronic acid, methyltartronic acid,
gluconic acid, glyceric acid, citric acid, tartaric
acid and salicylic acid.
Examples of aminocarboxylic acids are glycine,
glycylglycine, alanine, asparagine, glutamic acid,
aminobenzoic acid, iminodiacetic acid, iminotriacetic
acid, hydroxyethyliminodiacetic acid,
ethylenediaminotetraacetic acid,
hydroxyethylethylenediaminetriacetic acid,
diethylenetriaminepentaacetic acid and higher
homologues which are preparable by polymerization of an
N-aziridylcarboxylic acid derivative, for example of
acetic acid, succinic acid or tricarballylic acid, and
subsequent hydrolysis, or by condensation of polyamines
having a molecular weight of from 500 to 10,000 with
salts of chloroacetic or bromoacetic acid.
Preferred cobuilder substances are polymeric
carboxylic acids. These polymeric carboxylic acids
~J~ J~L~6
14
shall include the carboxymethyl ethers of sugars, of
starch and of cellulose.
Particularly important polymeric carboxylic acids
are for example the polymers of acrylic acid, maleic
acid, itaconic acid, mesaconic acid, aconitic acid,
methylenemalonic acid, citraconic acid and the like,
the copolymers between the aforementioned carboxylic
acids, for example a copolymer of acrylic acid and
maleic acid in a ratio of 70:30 and having a molecular
weight of 70,000, or copolymers thereof with
ethylenically unsaturated compounds, such as ethylene,
propylene, isobutylene, vinyl alcohol, vinyl methyl
ether, furan, acrolein, vinyl acetate, acrylamide,
acrylonitrile, methacrylic acid, crotorlic acid and the
like, e.g. the 1:1 copolymers of maleic anhydride and
methyl vinyl ether having a molecular weight of 70,000
or the copolymers of maleic anhydride and ethylene
and/or propylene and/or furan.
The cobuilders may further contain soil
antiredeposition agents which keep the dirt detached
from the fiber in suspension in the liquor and thus
inhibit graying. Suitable for this purpose are water-
soluble colloids usually of an organic nature, for
example the water-soluble salts of polymeric carboxylic
acids, glue, gelatin, salts of ethercarboxylic acids or
ethersulfonic acids of starch and of cellulose or salts
of acid sulfates of cellulose and of starch. Even
water-soluble polyamides containing acid groups are
suitable for this purpose. It is also possible to use
soluble starch products and starch products other than
those mentioned above, for example degraded starch,
aldehyde starches and the like. Polyvinylpyrrolidone
is also usable.
Examples of additional assistants are: Suitable
foam regulants, in particular if surfactants of the
sulfonate or sulfate type are used, are surface-active
carboxybetaines of sulfobetaines and also the
abovementioned nonionics of the alkylolamide type.
Also suitable for this purpose are fatty alcohols or
higher terminal diols.
Reduced foaming, which is desirable in particular
for machine washing, is frequently obtained by
combining various types of surfactants, for example
sulfates and/or sulfonates, with nonionics and/or with
soaps. In the case of soaps, the foam inhibition
increases with the degree of saturation and the number
of carbon atoms of the fatty acid ester; soaps of
saturated Cz0-C24-fatty acids, therefore, are
particularly suitable for use as foam inhibitors.
The nonsurfactant-like foam inhibitors include
possibly chlorine-containing N-alkylated aminotrizines
which are obtained by reacting 1 mole of cyanuric
chloride with from 2 to 3 moles of a mono-and/or
dialkylamine having 6 to 20, preferably ~ to 18, carbon
atoms in the alkyl. A similar effect is possessed by
propoxylated and/or butoxylated aminotriazines, for
example products obtained by addition of from 5 to 10
moles of propylene oxide onto 1 mole of melamine and
further addition of from 10 to 50 moles of butylene
oxide onto this propylene oxide derivative.
Other suitable nonsurfactant-like foam inhibitors
are water-insouble organic compounds, such as paraffins
or haloparaffins having melting points below 100C,
aliphatic C1B_ to C40-ketones and also aliphatic
carboxylic esters which, in the acid or in the alcohol
moiety, possibly even both these moieties, contain not
16
less than lB carbon atoms (for example triglycerides or
fatty acid fatty alcohol esters); they can be used in
particular in combinations of surfactants of the
sulfate and/or sulfonate type with soaps for foam
inhibition.
The detergents may contain optical brighteners for
cotton, for polyamide, for polyacrylonitrile of for
polyester fabrics. Examples o~ suitable optical
brighteners are derivatives of diaminostilbene-
disulfonic acid for cotton, derivatives of 1,3-
diarylpyrazolines for polyamide, ~aternary salts of 7-
methoxy-2-benzimidazol-2'-ylbenzofuran or of
derivatives from the class of the 7-[1',2l,5'-tria~ol-
l'yl]-3-[1",2",4"-triazol-l"yl]coumarins for
polyacrylonitrile. Examples of brighteners suitable
for polyester are products of the class of the
substituted styryls, ethylenes, thiophenes,
naphthalenedicarboxylic acids or derivatives thereof,
stilbenes, coumarins and naphthalimides.
Further possible assistants or formulation aids
are the conventional substances known to those skilled
in the art, for example solubilizers, such as
xylenesulfonates or cumenesulfonates, standardizing
agents, such as sodium sul~ate, enz~mes or scent oils.
It will be apparent from the foregoing that the
compositions of this invention may be formulated
according to any of the various commercially desirable
forms. For example, the formulations of this invention
may be provided in granular form, in liquid form, in
tablet form, or in the form of flakes or powders.
The relative proportions and absolute quantities
of the several ingredients of the finished compositions
of this invention are susceptible to variation and in
'~:C?~
most cases will vary depending upon such factors as the
nature of the particular ingredients being utilized,
the end use of which the composition is intended to be
put, the relative costs of the ingredients, and the
like. The p~eferred compositions o~ this invention are
phosphsrus-free although it may be desired to include
therein reduced quantities of conventional phosphorus-
containing materials such as sodium tripolyphosphate,
tetrasodium pyrophosphate, salts of substituted
methylene disphosphonic acids, long chain tertiary
phosphine oxides, or the like.
The invention is not to be limited to any
particular method of mixing the stabilizer and the
detergent. The stabilizer may be mechanically mixed
in, crutched in the detergent in the form of a slurry,
or dissolved in a solution of the detergent. In
addition, the stabilizer may be admixed with the
detergent in any of the forms in which the detergent i5
manufactured, as well as being added simultaneously or
separately to an aqueous solution. In any event, the
stabilizers of the invention are intended to be used
with the detergent at the time of application as a
cleansing agent.
In order to further illustrate the invention
detailed hereinabove, the following examples are
presented.
EXANPL~ I
(Preparation of Methyliminodiacetic Acid)
To 2 moles of chloroacetic acid in 150 ml of
water, were added 4 moles sodium hydroxide in 500 ml of
water, the reaction mixture being cooled on ice and
kept below 30C. After this the ice bath was removed
U~ r~
18
and 1 mole methylamine (as 30% aqueous solution) was
added slowly. The solution tempsrature was not allowed
to rise above 50C~ Evaporation of the water yielded
the product as a white solid.
~ANPLE II
(Perborate Stabilization in the Presence of Metal Ions)
The hydrogen p~roxide responsible for the
bleaching action in sodium perborate based laundry
detergents is decomposed catalytically by transition
metal ions such as MnII and CuII. This degradation can
be prevented by complexing the metal ions.
The peroxide stabilizing effect o~ stabilizers in
accordance with the invention was tested by measuring
the peroxide present before and after storage in a hot
aqueous solution which contains copper or manganese
ions.
Procedure
A solution of 0.2g (2 x 10-3 mols) sodium perborate
monohydrate; 10.0 ml of hardness standard (3:1
CaCl2:MgCl2, 1 x 10 6 mols total); 3.0 ml of metal
standard (5.4 x 10-8 mol MnII or 4.7 x 10-8 mols CUII);
and 2.0 ml stabilizer solution (4.2 x 10-7 mols
stabilizer) was diluted to 100 ml with distilled water.
The pH was adjusted to 10.1 and the solution was
stirred at 70C for 20 minutes. Ten ml aliquots of the
solution were tested after 10 minutes by first
neutralizing the solution with sulfuric acid and then
titrating with iodine and starch.
The percentage of peroxide remaining after storage
was determined using a starch/iodine titration
procedure. Results are recorded in Table I below.
2~
19
TABLE I
Effect of Bleach Stabilizers to Stabilize
Perborate in the Presence of Mn+2 and Cut2 Ions
Stability in Presence Stability in Presence
of MnZ Ions of Cu+2 Ions
Stabilizer~ Remain;ng % Remain;n~
MIDA1 64.0 64.0
EDTA2 87.5 82~8
1MIDA = Methyliminodiacetic acid
2EDTA = Ethylenediaminetetraacetic acid
EX~MPLE IlI
(Sodium Perborate Stabilization in Wash Liquors)
The efficiency of the bleaching action of a
laundry detergent containing the stabilizers of the
invention was measured by washing white poly-cotton
fabric swatches previously stained with grape juice.
The test was carried out using the following detergent
formulation:
Sodium dodecyl benzene sulfonate 12%
Nonylphenol (Neodol) 4%
Na2SOb 80%
Na Carbonate 20
Zeolite 29%
Na Silicate 5
Procedure
Grape juice stained, poly-cotton fabric swatches
purchased from Scientific Services, Oakland, NJ, were
washed in a TergitomQter at 50C for 15 minutes in a
wash solution containing sodium perborate-monohydrate
0.8 g/l; 4.0 g/l of the zeolite-based detergent as
described above; 100 ppm Hardness (3:1 Ca:Mg); 2 ppm
FeIII; 1 ppm CuI~; and 1 ppm MnII (from AA standards); and
5.2 x 10-5 mol/l stabilizer. The pH of the wash
solution was 10.30 The swatches were then rinsed for 5
minutes in 25C water and air dried.
The efficiency of the bleaching action was
determined by measuring the br:ightness (AE) of the
: 5 swatches and the percentage of soil removed from the
swatches.
~E was calculated in accordance with ASTM E 308-
66(81) standards, using the fo:Llowing formula:
~E = I (~L)2 + (~a)2 ~ (~b)2
wherein
L = Lightness 0 black, 100 white
a = Redness if +, Greenness if -, Gray is 0
b = Yellow if +, Blue if -, Gray is 0
~ measurements are before and after washing
Percent stain removal was calculated in duplicate
in accordance with ASTM D3050-75 standards, using the
following formula:
% Soil Removed = D after wash -_D before wash
D unstained fabric - D before wash
where D = reflectance by deterqent head with green
filter (brightness).
The results were compared to results obtained for
EDTA and are recorded in Table II below.
21
TABLE II
Stabilizer ~E % Stain Removal
,
MIDA1 91.3 80.2
EDTA2 86.2 79.7
1MIDA = Nethyliminodiacetic acid
ZEDTA - Ethylenediaminetetraacetic acid
It follows from the result.s that the chelating
agents described above, in combination with sodium
perborate, are effective in removing these stains.
E~AMPLE IV
(Determination of Biodegradability)
The biodegradability of bleach stabilizers
described hereinabove was determined using the Sturm ~2
Evolution Test (J. Amer. Oil Chem. Soc., 50,
159(1973)). The Sturm Test measures the ultimate
biodegradation of soluble organic materials. The term
"ultimate biodegradation" is defined herein to indicate
the complete mineralization of material to CO2, water,
and inorganic salts. In this test, the CO2 generated
from the degradation of the stabili~er of the invention
was trapped using a series of three barium hvdroxide
traps. The barium hydroxide reacted with the CO2 to
form barium carbonate and the amount of CO2 evolved was
determined by titrating the unreacted barium hydroxide
with hydrochloric acid.
Procedure
The test was conducted in a two liter flask with
the final volume of the test solution being one liter
(Final volume equals the volume of the medium plus the
volume of the test sample solution plus the volume of
2~ ¢~3
22
the inoculum). The test medium was a modified BOD
(Biochemical Oxygen Demand) water which contains, per
liter of distilled water, the following standard BOD
reagent solutions:
1.0 ml magnesium sulfate (2.25% w/v)
1.0 ml calcium chloride (2.75~ w/v)
4.0 ml ferric chloride (0.025% w/v)
1.0 ml ammonium sulfate (4.99% w/~)
2.0 ml phosphate buffer (pH 7.2)
W/V a weight per volume
A stock solution of the test ~ompound was prepared
at a concentration of 1000 mg/l and the pH adjusted to
7.0 if the initial pH was outside of a 4.0-10.0 pH
range.
The inoculum was prepared by taking unacclimated
sludge and homogenizing it for two minutes, at room
temperature, using a Waring Blender at medium speed.
The homogenized sample was transferred to a beaker and
left to settle for 15-30 minutes. The supernatant was
carefully decanted and 10 ml of this solution was added
to each test flask. Immediately prior to the beginning
of the test, the ~iability of the test organisms was
determined. There must be at least 1 x 106
microorganisms per milliliter before this inoculum can
be used. The inoculum was used the day it was
prepared.
Each test flask was charged with 980 ml of test
medium and then purged for twenty-four hours using CO2
free air. Following the removal of residual CO2, the
test flasks were connected to a series of three barium
hydroxide traps each containing 100 ml of 0.024 N
barium hydroxide. Ten milliliters of the test sample
stock solution was added to each flask followed by the
addition of 10 ml of the inoculum prepared above.
The head space of each flask was aerated with CO2
free air at a flow rate of 50--100 cc/min for the
duration of the test. Every 2-3 days the first barium
hydroxide trap (nearest to the test flask) was titrated
using 0.05N standardized HCl and the amount oE C2
evolved was determined. The xemaining two barium
hydroxide traps were moved forward to positions one and
two and a new barium hydroxide trap was placed in
position three. The length of the test was typically
26-30 days.
Included in each test were two blanks which were
titrated along with the test samples. The amount CO2
found for each sample was determined using the
following equation:
mg Co2(s~ple) = [ml titrant(5~p1e) - ml titrant(bl~ Ave)]
x 1.1
Each test also included a sample of glucose which
was used a~ a control to guarantee the activity of the
microorganisms.
Each stabilizer tested was degraded as described
hereinabove with the exception that AspDA was degraded
using acclimated microorganisms. The microorganisms
were acclimated in a bench scale semicontinuous
activate sludge system. The initial activated sludge
was adjusted to a suspended solids level of 2500-3000
mg/l. The activated sludge was exposed to increasing
levels of test material over a five day period (4, 8,
12, 16, and 20 mg/l) and then maintained at 20 mg/l for
X~,?~
24
an additional five days. The acclimated microorganisms
were th~n treated as described above prior to the start
of the Sturm test.
The results of each test are reported in Table III
below. Results are recorded as a percentage of the
theoretical CO2 expected to evolve if there was 100%
biodegradation. If the CO2 production for the glucose
flask did not plateau at 70% or more, the test results
were discarded. The theoretical CO2 for test samples
was determined using a Total Organic Carbon Analyzer or
other suitable analytical methods for determining total
organic carbon.
TABLE III
Biodegradation Properties of Aspartic Acid
and B-alanine Derivatives
Stabilizer % of Theoret. CO2
_ _ _
MIDA1 72%
citric acid 82%
NTAZ 73~
ylyc3ine 59%
EDTA o%
1MIDA = Methyliminodiacetic acid
2NTA = Nitrilotriacetic acid
3EDTA = Ethylenediaminetetraacetic acid
The principlPs, preferred embodiments and modes of
operation of the present invention have been described
in the foregoing specification. The invention which is
intended to be protected herein, however is not to be
construed as limited to the particular forms disclosed,
since these are to be regarded as illustrative rather
than restrictive. Variations and changes may be made
by those skilled in the art w:ithout departing from the
spirit of the invention.
