Note: Descriptions are shown in the official language in which they were submitted.
CA 02297861 2000-02-02
The Use of Phosphonic-acid-modified Polyacrylates as Sequestering
Agents
Field of the Invention
This invention relates to the use of phosphonic-acid-modified
polyacrylates as sequestering agents (sequestrants) for the production of
water-containing bleaching compositions.
Prior Art
In the cold washing of soiled textiles, liquid bleaching compositions,
preferably based on hypochlorite, are used in addition to a detergent for
removing particularly difficult stains. These liquid bleaching compositions
have to be compatible with textiles, i.e. the removal of stains by the
treatment with hypochlorite, an aggressive chemical, should take place
without any adverse effect on the textile. In addition, since skin contact
with the bleaching compositions cannot be ruled out, the preparations have
to be as dermatologically safe as possible. One particular problem is that
hypochlorite solutions are capable of dissolving iron and manganese ions
from the walls of the washing machine during the washing process. These
iron and manganese ions subsequently catalyze photochemical reactions
and lead to yellowing of the washing. Although commercially available
compositions attempt to prevent this redeposition through the use of
polyacrylates [DE 19730650 A1 (Henkel)], this measure has not always
proved satisfactory in practice.
Accordingly, the complex problem addressed by the present
invention was to prevent the yellowing of washing through the deposition of
metal traces on the washing and to provide sequestrants with which it
would be possible to produce water-based bleaching compositions, more
particularly chlorine bleaching liquors, which at one and the same time
would be chlorine-stable, kind to fabrics and dermatologically safe while
developing high stain removing power and which would have a sufficiently
CA 02297861 2000-02-02
2
high viscosity.
Description of the Invention
The present invention relates to the use of phosphonic-acid-modified
polyacrylates as sequestrants for the production of water-based bleaching
compositions.
It has surprisingly been found that the addition of small quantities of
phosphonic-acid-modified polyacrylates to water-based bleaching composi-
tions, more particularly to hypochlorite solutions, significantly reduces the
deposition of metal traces on the laundry during the washing process and,
in doing so, counteracts yellowing of the fibers. The invention includes the
observation that the use of other polyelectrolytes, buffers and optionally
chlorine-stable surfactants and optical brighteners leads to a further
improvement in stabilization against yellowing, in cleaning performance and
in dermatological compatibility.
Phosahonic-acid-modifiedJ~ol~acrylates
Polyacrylates are polymers based on esters of acrylic acid with a
characteristic chain unit corresponding to formula (I):
-[CHZ-CH(COOR~)]- (I)
in which R' is hydrogen or a linear or branched hydrocarbon radical
containing 1 to 22, preferably 2 to 12 and more preferably 3 to 8 carbon
atoms. Typical examples are polymers of acrylic acid and esters thereof
with methanol, ethanol, propanol, isopropyl alcohol, n-butanol, isobutanol,
sec.-butanol, tert.-butanol, pentanol, caproic alcohol, caprylic alcohol, 2-
ethylhexyl alcohol, capric alcohol, lauryl alcohol, isotridecyl alcohol,
myristyl
alcohol, cetyl alcohol, palmitoleyl alcohol, stearyl alcohol, isostearyl
alcohol,
oleyl alcohol, elaidyl alcohol, petroselinyl alcohol, linolyl alcohol,
linolenyl
CA 02297861 2000-02-02
3
alcohol, elaeostearyl alcohol, arachyl alcohol, gadoleyl alcohol, behenyl
alcohol, erucyl alcohol and brassidyl alcohol and the technical mixtures
thereof obtained, for example, in the high-pressure hydrogenation of
technical methyl esters based on fats and oils or aldehydes from Roelen's
oxosynthesis. Homopolymers or copolymers of acrylic acid and methyl,
tert.-butyl or 2-ethylhexyl esters thereof are preferably used. The resulting
polyacrylates are modified with phosphonic acid, the point of attachment of
the phosphonic acid group being situated on the carbon chain. The
polymers obtained can have average molecular weights of the order of 300
to 50,000, preferably in the range from 1000 to 30,000 and more preferably
in the range from 5000 to 10,000 dalton.
Polyelectrolytes
In one particular embodiment of the invention, the phosphonic-acid-
modified polyacrylates are used in combination with other already known
polyelectrolytes. These other electrolytes support the sequestering effect
of the polyacrylates according to the invention.
(a) Low molecular weight dicarboxylic acids. In the most simple case,
the polyelectrolytes used may be low molecular weight dicarboxylic acids
corresponding to formula (II):
R200C(CH2)~OOCR3 (II)
in which R2 and R3 represent hydrogen, an alkali metal and/or alkaline
earth metal, ammonium, alkylammonium, alkanolammonium or glucammo-
nium and n is a number of 0 to 64. Typical examples are oxalic acid,
malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic
acid, sebacic acid and the dimer and trimer fatty acids based on
unsaturated fatty acids, namely oleic acid, elaidic acid, gadoleic acid and
CA 02297861 2000-02-02
4
erucic acid. The dicarboxylic acids may be mono- or polyunsaturated
and/or may have an aromatic ring instead of the alkylene groups. Typical
examples are malefic acid, fumaric acid, sorbic acid, phthalic acid and
terephthalic acid. When the acids mentioned are introduced into the
alkaline bleaching composition, neutralization takes place. However, they
may also be directly used in the form of their salts, preferably sodium salts.
In one particularly preferred embodiment, adipic acid or sodium adipate is
used as the polyelectrolyte.
(b) Low molecular weight polybasic hydroxycarboxylic acids. Typical
examples of suitable polybasic hydroxycarboxylic acids are malic acid,
tartaric acid and in particular citric acid. These acids may also be used in
the form of their alkali metal and/or alkaline earth metal, ammonium,
alkylammonium, alkanolammonium or glucammonium salts. In one parti-
cularly preferred embodiment, citric acid or sodium citrate is used as the
polyelectrolyte.
(c) Homopolymers and copolymers of unsaturated dicarboxylic acids
and derivatives thereof. Unsaturated dicarboxylic acids suitable as mon-
omers have already been mentioned under (a). However, malefic anhy-
dride is preferably used by virtue of its high reactivity and its low price.
The
products obtainable, for example, by hydrolysis of polymaleic anhydride
have a high charge intensity. Ring structures formed by secondary
reactions during the polymerization reaction additionally provide the
molecules with a certain chain stiffness which has a favorable effect on
sequestering. Polymaleic anhydrides (PMAs) with molecular weights of
300 to 5000 dalton are known, for example, from US 3,810,835 (Ciba). Co-
polymers of PMA and poly(meth)acrylic acid with molecular weights of
1000 to 50,000 are mentioned in DE 242926 AS (Ciba). US 3,650,970
(Atlantic Richfield) describes copolymers of malefic anhydride and styrene
CA 02297861 2000-02-02
which have been subjected to ring opening with polyethylene glycol
(molecular weight 300 to 1000) and which also have a favorable sequester-
ing effect. The same applies to copolymers of malefic anhydride with
sulfonated styrene [FR2322831 A (Betz)], vinyl acetate [US 3,755,264
5 (Amicon]), methacrylic acid/styrene [US 4,065,607(Pfitzner)], allyl acetate
[US 4,001,134 (Grace)] and/or acrolein [DE 2404192 AS (Ciba)].
(d) Homopolymers and copolymers of unsaturated monocarboxylic
acid amides and derivatives thereof. This group of substances are
preferably compounds which are obtained either by (co)polymerization of
the monomers or by polymer-analog hydrolysis of poly(meth)acrylamide or
poly(meth)acrylonitrile. The production of a polyacrylamide with a
molecular weight of 500 to 5000 dalton by using thioglycolic acid as
regulator and alkaline hydrolysis of 60 to 90% of the amide groups is
described, for example, in US 4,001,161 (Cyanamid). A polymer of similar
composition is obtained in accordance with US 3,492,240 (Nalco). The
product contains 20 to 50% amide groups and 50 to 80% carboxyl groups
and has a molecular weight of 20,000 to 40,000. In addition, CA 982341
(Nalco) describes a hydrolyzed polyacrylonitrile which contains 20 to 30%
amide groups and 70 to 80% acid groups and has a molecular weight of
5000 to 40,000. Graft polymers of acrylamide or acrylonitrile on starch or
vinyl alcohol and hydrolysis products thereof [cf. NL 6615265 (ICI)] are also
suitable.
(e) Other anionic and cationic polyelectrolytes. Besides the
compounds mentioned, the following compounds are also suitable
polyelectrolytes: poly-(N,N-bis-carboxymethylene acrylamide) [cf. GB
1,310,613 A (Chemed)], copolymers of fumaric acid and vinyl sulfonic acid
[cf. US 3,879,288, US 3,706,717 (Siegele)], polymers of 3-acylamido-3-
methylpropane sulfonic acid (cf. US 3,709,815, US 3,928,916 (Calgon)],
CA 02297861 2000-02-02
6
copolymers of acrylic acid and styrene sulfonic acid [cf. US 4,048,066
(Chemed)], copolymers of acrylic acid with 2-hydroxyethyl methacrylate
monophosphate [cf. JA 76/112447 A (Sanyo)], homopolymers and
copolymers of 3-acrylamido-3-methyl butyl trimethyl ammonium chloride
[cf. US 3,752,761 (Calgon)], copolymers of diallyl glycinamide
hydrochloride and acrylic acid [cf. US 3,574,175 (Grace)], copolymers of
dimethyl allyl ammonium chloride with acrylamide [cf. GB 1,287,489 A],
polyethylene and/or polypropylene imines [cf. GB 1,015,612 A (Grace)] and
mixtures thereof.
Alkali metal ~pochlorites
Although the water-based bleaching compositions may contain
hydrogen peroxide, they are preferably chlorine bleaching liquors
containing alkali metal hypochlorite. Alkali metal hypochlorites in the
context of the present invention are understood to be lithium, potassium
and, in particular, sodium hypochlorite. The hypochlorites may be used in
quantities of 1.5 to 10% by weight, preferably in quantities of 2 to 8% by
weight and more preferably in quantities of 4 to 6% by weight, based on the
composition.
B uffe rs
In one preferred embodiment of the invention, the phosphonic-acid-
modified polyacrylates are used in combination with buffers which are alkali
metal and/or alkaline earth metal silicates, carbonates, phosphonates or
mixtures thereof. The salts support the sequestering effect of the poly-
electrolytes and ensure that the preparations always have a highly alkaline
pH in the range from 10 to 14. Typical examples are sodium silicate,
potassium silicate, sodium carbonate, potassium carbonate and - from the
group of phosphonates - above all the amine oxide phosphonic acids
marketed, for example, under the name of Sequion~ by Bozetto, Italy, for
CA 02297861 2000-02-02
7
example the aminotrimethylene phosphonic acid-N-oxide (ATMP-N-oxide)
obtainable as Sequion~ CLR. The buffers may be used individually or in
the form of mixtures in quantities of 0.01 to 5% by weight, preferably in
quantities of 0.1 to 2% by weight and more preferably in quantities of 0.5 to
1 % by weight, based on the composition.
Chlorine-stable surfactants
(a) Alkyl ether sulfates are known anionic surfactants which are obtained
by sulfation of nonionic surfactants of the alkyl polyglycol ether type and
subsequent neutralization. The alkyl ether sulfates suitable for use in the
compositions according to the invention correspond to formula (111):
R4O-(CH2CH2O)qSO3X (III)
in which R4 is an alkyl group containing 12 to 18 and more particularly 12 to
14 carbon atoms, q is a number of 2 to 5 and, more particularly, 2 to 3 and
X is sodium or potassium. Typical examples are the sodium salts of
sulfates of the C~2,~4 cocoalcohol 2, 2.3 and 3 EO adduct. The alkyl ether
sulfates may have a conventional or narrow homolog distribution. The alkyl
ether sulfates are used in quantities of preferably 1 to 8% by weight, more
preferably 1.5 to 6% by weight and most preferably 2 to 4% by weight,
based on the composition.
(b) Amine oxides are also known compounds which are occasionally
classified as cationic surfactants, but generally as nonionic surfactants.
They are produced from tertiary fatty amines which normally have either
one long and two short alkyl chains or two long and one short alkyl chain by
oxidation in the presence of hydrogen peroxide. The amine oxides suitable
for use in the compositions according to the invention correspond to
formula (IV):
CA 02297861 2000-02-02
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Rs
Rs_N_>O . (IV)
R'
in which R5 is a linear or branched alkyl group containing 12 to 18 carbon
atoms and Rs and R' independently of one another have the same
meaning as R5 or represent an optionally hydroxy substituted alkyl group
containing 1 to 4 carbon atoms. Amine oxides of formula (IV), in which R5
and R6 represent C~2,~a or C~2,~s cocoalkyl groups and R' is a methyl or
hydroxyethyl group, are preferably used. Amine oxides of formula (IV), in
which R5 is a C~2,~a or C~2,~a cocoalkyl group and Rs and R' represent a
methyl or hydroxyethyl group, are also preferred. The amine oxides are
preferably used in quantities of 1.5 to 6% by weight and preferably 2 to 4%
by weight, based on the composition.
(c) Alkyl and/or alkenyl oligoglycosides are known nonionic surfactants
corresponding to formula (I):
Ra0-[G]p
(V)
in which R8 is an alkyl and/or alkenyl group containing 4 to 22 carbon
atoms, G is a sugar unit containing 5 or 6 carbon atoms and p is a number
of 1 to 10. They may be obtained by the relevant methods of preparative
organic chemistry. EP 0 301 298 A1 and WO 90103977 are cited as
representative of the extensive literature available on the subject. The alkyl
and/or alkenyl oligoglycosides may be derived from aldoses or ketoses
containing 5 or 6 carbon atoms, preferably glucose. Accordingly, the
preferred alkyl and/or alkenyl oligoglycosides are alkyl and/or alkenyl
oligoglucosides. The index p in general formula (V) indicates the degree
CA 02297861 2000-02-02
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of oligomerization (DP), i.e. the distribution of mono- and oligoglycosides,
and is a number of 1 to 10. Whereas p in a given compound must always
be an integer and, above all, may assume a value of 1 to 6, the value p for
a certain alkyl oligoglycoside is an analytically determined calculated
quantity which is generally a broken number. Alkyl and/or alkenyl oligo-
glycosides having an average degree of oligomerization p of 1.1 to 3.0 are
preferably used. Alkyl and/or alkenyl oligoglycosides having a degree of
oligomerization of less than 1.7 and, more particularly, between 1.2 and 1.4
are preferred from the applicational point of view. The alkyl or alkenyl
radical R8 may be derived from primary alcohols containing 4 to 11 and
preferably 8 to 10 carbon atoms. Typical examples are butanol, caproic
alcohol, caprylic alcohol, capric alcohol and undecyl alcohol and the
technical mixtures thereof obtained, for example, in the hydrogenation of
technical fatty acid methyl esters or in the hydrogenation of aldehydes from
Roelen's oxosynthesis. Alkyl oligoglucosides having a chain length of C$ to
Coo (DP = 1 to 3), which are obtained as first runnings in the separation of
technical C8_~8 coconut oil fatty alcohol by distillation and which may
contain
less than 6% by weight of C~2 alcohol as an impurity, and also alkyl oligo-
glucosides based on technical C9,» oxoalcohols (DP = 1 to 3) are
preferred. In addition, the alkyl or alkenyl radical R$ may also be derived
from primary alcohols containing 12 to 22 and preferably 12 to 14 carbon
atoms. Typical examples are lauryl alcohol, myristyl alcohol, cetyl alcohol,
palmitoleyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol,
elaidyl
alcohol, petroselinyl alcohol, arachyl alcohol, gadoleyl alcohol, behenyl
alcohol, erucyl alcohol, brassidyl alcohol and technical mixtures thereof
which may be obtained as described above. Alkyl oligoglucosides based
on hydrogenated C,2,~4 cocoalcohol with a DP of 1 to 3 are preferred. The
glycosides are preferably used in quantities of 1.5 to 6% by weight and
more preferably in quantities of 2 to 4% by weight.
CA 02297861 2000-02-02
(d) The compositions according to the invention may contain as further
surfactants fatty acid salts corresponding to formula (VI):
R9C0-OX (VI)
5
in which R9C0 is an acyl group containing 12 to 22 carbon atoms and X is
an alkali metal. Typical examples are the sodium and/or potassium salts of
lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, iso-
stearic acid, oleic acid, elaidic acid, petroselinic acid, linoleic acid,
linolenic
10 acid, elaeostearic acid, arachic acid, gadoleic acid, behenic acid and
erucic
acid and the technical mixtures thereof obtained in the pressure hydrolysis
of technical fats and oils. Salts of technical cocofatty acid or tallow fatty
acid are preferably used. Since the compositions according to the
invention are highly alkaline, the salts may even be replaced by the fatty
acids which are neutralized in situ on introduction into the mixture.
Compositions according to the invention which are required to be
particularly low-foaming preferably contain fatty acid salts as an optional
component. The soaps are used in quantities of preferably 1.5 to 6% by
weight and more preferably 2 to 4% by weight, based on the composition.
Commercial Apa~lications
The bleaching compositions obtainable using polyacrylates in
accordance with the invention generally have a non-aqueous component of
5 to 35% by weight and preferably 8 to 15% by weight and are particularly
suitable for the treatment of textiles such as, for example, yarns, webs and,
in particular, fabrics. They are normally used at low temperatures, i.e. at
cold wash temperatures (ca. 15 to 25°C). Not only are the compositions
distinguished by excellent stain removal, they also reliably prevent the
deposition of metal traces on the fibers and thus prevent yellowing.
Although the actual use of the compositions is directed at the removal of
CA 02297861 2000-02-02
11
stains during washing, they are also suitable in principle for other
applications where hypochlorite solutions are used, for example for the
cleaning and disinfection of hard surfaces.
Additional auxiliaries and additives which may be used include, for
example, other chlorine-stable surfactants or hydrotropes such as, for
example, alkyl sulfates, alkyl sulfonates, alkyl benzenesulfonates, xylene
sulfonates, sarcosinates, taurides, isethionates, sulfosuccinates, betaines,
sugar esters, fatty alcohol polyglycol ethers and fatty acid-N-alkyl
glucamides. In one preferred embodiment, all the surfactants together
make up at most 10 to 15% by weight of the total quantity of ingredients in
the composition. The compositions according to the invention may contain
alkali metal compounds, preferably sodium hydroxide or potassium
hydroxide, with which the pH of the compositions can be adjusted to an
optimal value of 10 to 14 and preferably 12.5 to 13.5.
Typical examples of suitable optical brighteners are derivatives of
diaminostilbene disulfonic acid and alkali metal salts thereof. Suitable
optical brighteners are, for example, derivatives of 4,4'-diamino-2,2'-
stilbene disulfonic acid (flavonic acid), such as in particular the salts of
4,4'-
bis-(2-anilino-4-morpholino-1,3,5-triazinyl-6-amino)-stillbene-2,2'-disulfonic
acid or compounds of similar structure which, instead of the morpholino
group, contain a diethanolamino group, a methylamino group, an anilino
group or a 2-methoxyethylamino group. Other brighteners which may be
present are those of the substituted diphenyl styryl type, for example alkali
metal salts of 4,4'-bis-(2-sulfostyryl)-Biphenyl, 4,4'-bis-(4-chloro-2-sulfo-
styryl)-Biphenyl or 4-(4-chlorostyryl)-4'-(2-sulfostyryl)-Biphenyl, methyl
umbelliferone, coumarin, dihydroquinolinone, 1,3-diaryl pyrazoline,
naphthalic acid amide, benzoxazole, benzisoxazole and benzimidazole
systems linked by CH=CH bonds, heterocycle-substituted pyrene
derivatives and the like. Mixtures of the brighteners mentioned above may
also be used. The potassium salt of 4,4'-bis-(1,2,3-triazolyl)-(2)-stilbine-
CA 02297861 2000-02-02
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2,2-sulfonic acid marketed under the name of Phorwite~ BHC 766 is
preferred. The compositions generally contain the optical brighteners in
quantities of 1 to 5% by weight and preferably in quantities of 2 to 3% by
weight. In addition, blue dyes may also be present in small quantities. A
particularly preferred dye is Tinolux~ (Ciba-Geigy).
Typical examples of suitable perfumes stable to active chlorine
are: citronellol (3,7-dimethyl-6-octen-1-ol), dimethyl octanol (3,7-dimethyl-1-
octanol), hydroxycitronellol (3,7-dimethyloctane-1,7-diol), mugol (3,7-
dimethyl-4,6-octatrien-3-ol), myrcenol (2-methyl-6-methylene-7-octen-2-ol),
terpinolene (p-mentho-1,4-(8)-diene), ethyl-2-methyl butyrate, phenyl propyl
alcohol, galaxolide (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclo-
pental-2-benzopyran), tonalide (7-acetyl-1,1,3,4,4,6-hexamethyl tetrahydro-
naphthalene), rose oxide, linalol oxide, 2,6-dimethyl-3-octanol, tetra-
hydroethyl linalool, tetrahydroethyl linalyl acetate, o-sec.-butyl cyclohexyl
acetate and isolone diphorenepoxide and also isoborneal, dihydroterpineol,
isobornyl acetate, dihydroterpenyl acetate). Other suitable perfumes are
the substances mentioned columns 3 and 4 of European patent application
EP 0622451 A1 (Procter & Gamble).
Suitable pigments are inter alia green chlorophthalocyanines
(Pigmosol~ Green, Hostaphine~ Green) or yellow Solar Yellow BG 300
(Sandoz). The compositions according to the invention are prepared by
stirring. The product obtained may optionally be decanted or filtered to
remove foreign bodies and/or agglomerates. In addition, the compositions
have a viscosity below 100 mPas and preferably below 50 mPas, as
measured at 20°C in a Brookfield viscosimeter (spindle 1, 10 r.p.m.).
Examples
In order to test the bleaching effect, soiled fabrics were treated with
various bleaching solutions. Yellowing was photochemically determined
CA 02297861 2000-02-02
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using the starting value of the soiled fabric as standard (100%). The
measurements were carried out in a liquor with a metal ion content of 300
ppb iron and 100 ppb manganese; the water hardness was 1000 ppm
CaCl2; the hydrogen carbonate content was 0.013% by weight. The liquor
ratio of fabric to water was 1:50 and the contact time was 30 minutes at a
temperature of 40°C. The results are set out in Table 1.
Table 1
Bleaching effect (quantities in % by weight)
E
~orrii a~i~i~~rt~' ~t~~rrn~~~~'t 2~, .. ~~~ ' -.~2
' v .-..
... ....~......_..... .. .._
...__
Sodium hypochlorite 5.0 5.0 5.0 5.0 5.0
Sodium hydroxide 0.7 0.5 0.5 0.5 0.5
Sodium silicate 0.1 0.1 0.1 0.1 0.1
Polyacrylic acid, phosphonic-acid-0.055 0.2 0.3 - -
modified~~
Polyacrylic acid2~ - - - 0.3 -
Amine oxide phosphonic acid3~0.1 0.1 0.1 0.1 0.1
Yellowing [%-rel.] 86 82 79 90 93
Norasol~ 470 N (Rohm & Haas / DE)
Carbopol~ EX 497 (BF Goodrich / BG)
Sequion~ (Bozetto / IT)
