Note: Descriptions are shown in the official language in which they were submitted.
CA 02315889 2000-08-14
PREVENTION OF DEPOSITS
Field of the Invention
The present invention relates to a composition which
prevents deposits on heating rods during the machine
washing of textiles.
Background of the Invention
Deposits on heating rods consist primarily of calcium
and magnesium compounds and also, when using certain
laundry detergents containing silicate and zeolite, of
smaller amounts of silicatic and aluminosilicatic
deposits. These deposits come about in particular
because of the hardness of the water used.
The major constituents of the hardness in water are
salts of calcium and magnesium, especially the
chlorides, sulfates and bicarbonates, which are
referred to as so-called hardness formers. Since under
heat the bicarbonates are converted into carbonates, a
fraction of the calcium salts is precipitated as CaC03,
whose solubility is low, when washing at elevated
temperatures. At high magnesium concentrations, basic
magnesium carbonates are also precipitated. If the
laundry detergents used themselves comprise carbonate,
in the form, for example, of alkali metal carbonates or
of precursors which release carbonate during the wash
process, such as percarbonates, for example, then this
carbonate content further promotes the formation of
insoluble calcium and magnesium carbonate residues on
the heating rods. Especially in regions of high water
hardness, i.e., water hardness of more than 140 mg of
calcium oxide per liter (14°d - 14 degrees on the
German hardness scale), deposits of this kind on
heating rods constitute a great problem.
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Complexing agents have been added to laundry detergents
and cleaning products in an attempt to prevent the
deposition of such compounds.
Although substances such as ethylenediaminetetraacetate
(EDTA) and nitrilotriacetate (NTA) are highly suited to
this purpose, their high heavy metal binding capacity
means that they are undesirable on ecological grounds.
The use in larger amounts of phosphates or
phosphonates, such as hydroxyethanediphosphonic acid
and its salts, for example, is also ruled out by
ecological concerns.
Furthermore, copolymers of acrylic and malefic acid, as
well, are used in order to disperse calcium carbonate
in the wash liquor. For example, European Patent
EP-B-628627 proposes a water softener in tablet form
that is intended for use in addition to a laundry
detergent or cleaning product. Said water softener
consists of from 60 to 98~ by weight of a combination
of citrate/citric acid and a water softening polymer,
plus polyethylene glycol and other auxiliaries. The
polymer is either a peptide-based biodegradable polymer
or a malefic acid-acrylic acid copolymer, e.g., Sokalan
CP5.
German Laid-Open Specification DE 2240309 describes a
composition containing from 5 to 40~ by weight of
surfactant, from 30 to 70~ by weight of alkali metal
carbonate, from 1 to 30~ by weight of complexing agent,
preferably citrate, and from 0.05 to 15~ by weight of
an antideposition agent for calcium carbonate. Said
antideposition agent is alternatively a phosphate, a
phosphonic acid, or a polymeric carboxylate.
European Patent Application EP-A-869169 describes a
laundry detergent containing from 5 to 80~ by weight of
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sodium carbonate, from 5 to 24% by weight of
surfactant, and from 0.5 to 25% by weight of a maleate
copolymer having a molecular mass of between 500 and
7000 g/mol and consisting to the extent of at least 50%
by weight of maleate units, at least 70 mol% of which
are neutralized, and from 10 to 50 mol% of acrylate
units, as well as from 1 to 10 mol% of nonionic
comonomers. This specific copolymer is used first to
improve the wash performance and second to prevent the
deposition of hardness formers on the laundry.
References to its effect on heating rod deposits are
absent from the document, however.
The patent application WO 93/05133 proposes preventing
encrustation by using a composition which contains no
polycarboxylates. The formation of calcium carbonate is
prevented by delaying the availability of the alkali
metal carbonate present in the laundry detergent or
cleaning product. This can be done by adding it later
or by treating the alkali metal carbonate with, for
example, a silicate coating, which reduces the
dissolution rate of the alkali metal carbonate.
The laundry detergent compositions of European Patent
EP-B-572288 contain from 10 to 30% by weight of alkali
metal carbonate, from 2 to 10% by weight of an
amorphous aluminosilicate, and from 3 to 15% by weight
of a growth inhibitor for calcium carbonate crystals,
which may comprise polyaspartic acid, a phosphonic
acid, a copolymeric polycarboxylate having a molecular
mass of between 50,000 and 70,000 g/mol, or a
polyacrylate having a molecular mass of from 2 to
10,000 g/mol, citrate, or other carboxylic acids. Key
to the action of this composition is the function of
the amorphous aluminosilicate as a host lattice for
calcium-containing deposits.
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European Patent Application EP-A-130640 describes a
laundry detergent composition comprising besides
surfactants and phosphate-free builder substances from
0.3 to 5% by weight of a polyacrylate polymer of this
kind having a molecular mass of between 2000 and
10,000 g/mol. This composition possesses particular
advantages in the removal of clay soiling from the
laundry. The compositions contain from 5 to 80% by
weight of builder substances, which may be selected
from a broad spectrum of organic and inorganic
compounds. In particular, zeolites, carboxylates,
carbonates, and alkali metal silicates are mentioned
here. There are no references in the document to the
effect that the polymers prevent the formation of
deposits on heating rods.
A laundry detergent builder whose advantages include
inhibiting deposits on heating rods is described in
DE 3715051. It comprises a silicate, which binds
calcium ions, and also a mixture of two different
acrylic acid polymers having different viscosity
numbers. Said mixture may comprise two homopolymers,
one homopolymer and one copolymer of acrylic acid (at
least 50 mol%) with monomers of other ethylenically
unsaturated dicarboxylic acids (C3_g), for example,
methacrylic acid, itaconic acid or malefic acid, or else
two copolymers. In a proportion of up to 20 mol% the
copolymers may include carboxyl-free ethylenically
unsaturated monomers.
The earlier German Patent Application DE 19858888.7
describes a process for preventing deposits on heating
rods during the machine washing of textiles, said
process taking place using water of any desired
hardness and a water softener whose principal inorganic
constituents comprise crystalline aluminosilicate and
alkali metal carbonate. A polymeric polycarboxylate
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having a molecular mass of less than 10,000 g/mol is
used as encrustation inhibitor.
Su~nary of the Invention
It has now been found that certain polymeric
polycarboxylates are especially suitable for reducing
the formation of residues on heating rods.
This invention firstly provides, accordingly, a laundry
detergent or cleaning product apt to prevent deposits
on heating rods, comprising a polycarboxylate having a
molecular mass of less than 4000 g/mol as measured by
means of GPC against a polyacrylate standard.
The present invention secondly provides a coarse-
particled laundry detergent or cleaning product or
compound therefor having an average particle size of
between 0.2 and 4.0 mm, apt to prevent deposits on
heating rods, which comprises a polymeric
polycarboxylate having a molecular mass of less than
10,000 g/mol as measured by means of GPC against a
polyacrylate standard.
The present invention further provides a process for
preventing deposits on heating rods during the machine
washing of textiles, using water of any desired
hardness and a water softener whose principal inorganic
constituents comprise crystalline aluminosilicate and
alkali metal carbonate, wherein a polymeric
polycarboxylate having a molecular mass of less than
4000 g/mol as measured by means of GPC against a
polyacrylate standard is used as encrustation
inhibitor.
Accordingly, the present invention additionally
provides for the use of polymeric polycarboxylates
having a molecular mass of less than 4000 g/mol as
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measured by means of GPC against a polyacrylate
standard for preventing deposits on heating rods during
the machine washing of textiles.
The molecular masses reported in this document for
polymeric polycarboxylates are weight-average molecular
masses Mw, determined basically by means of gel
permeation chromatography (GPC) using a W detector.
The measurement was made against an external
polyacrylate standard, which owing to its structural
similarity to the polymers under investigation provides
realistic molecular weight values. These figures differ
markedly from the molecular weight values obtained
using polystyrenesulfonic acids as the standard. The
molecular masses measured against polystyrenesulfonic
acids are generally higher than the molecular masses
reported in this document.
Detailed Description of the Invention
In accordance with the invention, the polymeric
polycarboxylate is preferably a polyacrylate, in
particular a homopolymeric polyacrylate. Particularly
preferred polycarboxylates have a molecular mass of
less than 3500 g/mol, preferably between 3500 and
1500 g/mol, and with particular preference between 3000
and 2000 g/mol as measured by means of GPC against a
polyacrylate standard. These polymeric polycarboxylates
of the invention are frequently referred to below
simply as the polycarboxylates. That designation in the
text below means, specifically, the polymers of the
invention.
In accordance with the invention, said polycarboxylate
may also comprise copolymeric polycarboxylates,
especially those of acrylic acid with methacrylic acid
and of acrylic acid or methacrylic acid with malefic
acid. Copolymers which have been found particularly
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suitable are those of acrylic acid with malefic acid,
containing from 50 to 90% by weight of acrylic acid and
from 50 to 10% by weight of malefic acid. To improve the
solubility in water, the polymers may also include
allylsulfonic acids as monomers, such as allyloxy-
benzenesulfonic acid and methallylsulfonic acid, for
example. Particular preference is also given to
biodegradable polymers of more than two different
monomer units, for example, those whose monomers
comprise salts of acrylic acid and of malefic acid and
also vinyl alcohol and/or vinyl alcohol derivatives, or
salts of acrylic acid and of 2-alkylallylsulfonic acid,
and also sugar derivatives. Further preferred
copolymers are those comprising as monomers preferably
acrolein and acrylic acid/acrylic acid salts or
acrolein and vinyl acetate.
The polycarboxylates of the invention are preferably in
neutralized form; that is, they have been neutralized
to the extent of, preferably, at least 70 mol%. The
carboxylates are preferably in the form of their alkali
metal salts, in particular in the form of the sodium
salts. In specific embodiments, however, it may also be
preferable for the polymers to be in their acid form,
i.e., with a degree of neutralization of less than
50 mol%, preferably less than 30 mol%.
It is additionally preferred if these polycarboxylates
have a narrow molecular mass distribution. A narrow
molecular mass distribution in this respect means that
there are markedly preferred chain lengths and that the
distribution curve falls off sharply either side of
this maximum. Particularly narrow molecular mass
distributions show a steep drop in this respect. The
molecular mass distribution may be measured as the
ratio formed from the weight-average molecular mass MW
and the number-average molecular mass Mn of the
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polymers. This ratio constitutes a measure of the
uniformity or polydispersity, and is larger the wider
the molecular mass distribution. Defined molecular
compounds possess a ratio MW/Mn = 1. Polymers, in
contrast, normally have ratios MW/Mn of considerably
greater than 1, it being entirely possible for
industrial polymers to have values of considerably
greater than 10. The polymers of the invention,
however, preferably possess a ratio Mw/Mn of less than
10, usually markedly less than 10. Polymers preferred
in accordance with the invention even have a ratio MW/Mn
of less than 8, in particular even less than 5. In a
likewise preferred embodiment, the polymers have a
ratio of less than 2, and, especially if the polymers
have been prepared by means of a living addition
polymerization, they may also have a ratio of less than
1.5. In another preferred embodiment, the polymers have
a ratio MW/Mn from the range from 2 to 7. In accordance
with the invention, all molecular mass distributions
for which the ratio MW/Mn < 10 are labeled narrow.
The compositions of the invention comprising such
polycarboxylates show significantly lower deposits on
heating rods than comparable compositions comprising
other polymeric builders, especially those comprising
as sole polymeric polycarboxylate a copolymer of
acrylic acid with malefic acid having a molecular mass
of more than 20,000 g/mol. The wash properties of
laundry detergents comprising the polymers of the
invention are entirely comparable with the properties
of laundry detergents comprising said copolymer; in the
case of specific types of soiling, the compositions of
the invention in fact give better results.
The compositions of the invention may be in solid or
liquid form, although it is preferred if the
compositions are in solid form. The solid compositions
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may take on any desired form. This may embrace
compositions in powder or granule form as well as
tablets. The tablets may have virtually any desired
three-dimensional shape and size. Suitable three-
dimensional shapes include virtually any practicable
designs - i.e., for example, bar, rod or ingot forms,
cubes, blocks and corresponding three-dimensional
elements having planar side faces, and, in particular,
cylindrical designs with a circular or oval cross
section. This latter design covers forms ranging from
tablets through to compact cylinders having a height-
to-diameter ratio of greater than 1.
The solid compositions of the invention may have any
desired bulk densities. The pallet of possible bulk
densities ranges from low bulk densities below 600 g/1,
for example, 300 g/1, via the range of medium bulk
densities from 600 to 750 g/l, through to the high bulk
density range of at least 750 g/1. In one preferred
variant of the compositions of the invention with high
bulk densities, however, the bulk density is even above
800 g/1, with bulk densities of more than 850 g/1
possibly being particularly advantageous.
In one preferred embodiment, the compositions of the
invention comprise coarse-particle laundry detergents
or cleaning products or compounds therefor, having an
average particle size of between 0.2 and 4.0 mm and
comprising a polymeric polycarboxylate having a
molecular mass of less than 10,000 g/mol as measured by
means of GPC against a polyacrylate standard.
Especially when this coarse-particle laundry detergent
or cleaning product or compound therefor has been
prepared from a premix that already includes the
polymeric polycarboxylate having a molecular mass of
less than 10,000 g/mol, the effect according to the
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invention is found even with polymeric polycarboxylates
having molecular masses of less than 10,000 g/mol. In
one preferred embodiment, this coarse-particle laundry
detergent or cleaning product or compound therefor
comprises a polymeric polycarboxylate having a
molecular mass of less than 8000 g/mol, in particular a
molecular mass from the range from 3000 to 8000 and,
with particular preference, from the range from 4000 to
5000 g/mol as measured by means of GPC against a
polyacrylate standard. In another, particularly
preferred embodiment, however, the compositions
comprise specifically the polycarboxylates with
molecular masses of less than 4000 g/mol that were
described earlier on above. In that case the effect
according to the invention is particularly strongly
pronounced.
The coarse-particled compositions have preferred bulk
densities of more than 600 g/1, in particular more than
700 g/1. In one particularly preferred embodiment, the
bulk densities are between 750 and 1000 g/1. The
average particle sizes of these coarse-particled
compositions are in the range from 0.2 to 4.0 mm, the
average particle sizes in preferred embodiments being
between 0.8 and 3.0 mm, in particular between 1.0 and
2.0 mm. In one preferred embodiment, these compositions
comprise compositions prepared from a solid premix
which comprises individual raw materials and/or
compounded components which are present as solids at
room temperature under a pressure of 1 bar and have a
melting point or softening point of not below 45°C, and
further comprises, if desired, up to 10~ by weight of
nonionic surfactants which are liquid at temperatures
below 45°C under a pressure of 1 bar, said premix being
essentially free from water and comprising at least one
raw material or compounded component which is in solid
form under a pressure of 1 bar and at temperatures
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below 45°C but under the premix processing conditions
is in the form of a melt that acts as a polyfunctional,
water-soluble binder that during the preparation of the
compositions performs the function both of a lubricant
and of an adhesive for the solid laundry detergents or
cleaning products but has a disintegrating action when
the composition is redissolved in an aqueous liquor. In
one preferred embodiment, these coarse-particled
compositions of the invention comprise compacted forms,
especially extrudates.
In one preferred embodiment of the invention, the
coarse-particled compositions are prepared by
extrusion, as described, for example, in European
Patent EP-B-486592 or in International Patent
Applications WO 93/02176 and WO 94/09111 or
WO 98/12299. Here, a solid premix is extruded under
pressure in the form of a strand and the strand,
following its emergence from the die plate, is cut to
the predeterminable granule dimensions by means of a
pelletizer. The homogeneous and solid premix comprises
a plasticizer and/or lubricant, the effect of which is
that the premix, under the pressure or under the
application of specific energy, softens plastically and
becomes extrudable. Preferred plasticizers and/or
lubricants are surfactants and/or polymers.
As regards explaining the actual extrusion process,
reference is hereby made specifically to the
abovementioned patents and patent applications. In one
preferred embodiment of the invention, the premix is
preferably supplied continuously to a planetary roll
extruder or a twin-screw extruder with co- or counter-
rotating screws, whose barrel and whose extruder-
pelletizing die may be heated to the predetermined
extrusion temperature. Under the shear effect of the
extruder screws, the premix - under pressure,
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preferably at least 25 bar but possibly below this
level at extremely high throughputs, depending on the
apparatus used - is compacted, plasticated, extruded in
the form of fine strands through the perforated die
plate in the extruder head, and finally comminuted by
means of a rotary chopping knife, to give, preferably,
approximately spherical to cylindrical granules. The
perforation diameter of the perforated die plate and
the strand cutting length are tailored to the chosen
granule dimensions. In this embodiment, it is possible
to prepare granules of an essentially uniformly
predeterminable particle size, it being possible
specifically to adapt the absolute particle sizes to
the intended application. In general, particle
diameters of up to a maximum of 0.8 cm are preferred.
Important embodiments provide here for the preparation
of uniform granules in the millimeter range, for
example, in the range from 0.5 to 5 mm, and in
particular in the range from about 0.8 to 3 mm. The
length/diameter ratio of the chopped primary granules
in one important embodiment is in the range from
approximately 1:1 to approximately 3:1. It is further
preferred to transfer the still plastic primary
granules to a further shaping step; here, edges on the
raw extrudate are rounded off, thus making it possible
to obtain, ultimately, extrudate granules which are
spherical to approximately spherical in shape. If
desired, small amounts of dry powder, for example,
zeolite powders such as zeolite NaA powder, may also be
used at this stage. This shaping operation may be
carried out in commercial rounding devices. It is
important to ensure that only small amounts of fine
particle fraction are formed in this stage. Subsequent
drying, which is described as a preferred embodiment in
the abovementioned prior art documents, is possible but
not mandatory in accordance with the invention. It may
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be specifically preferred to carry out no drying
following the compacting step.
Alternatively, extrusion/compression operations may be
conducted in low-pressure extruders, in the Kahl press
(from Amandus Kahl) or in the Bextruder from Bepex.
In one particularly preferred embodiment, the invention
envisages the temperature regime in the transition zone
of the screw, the manifold and the die plate being such
that the melting point of the binder, or the upper
limit of the melting range of the binder, is at least
reached and, preferably, is exceeded. The duration of
the temperature exposure in the compression zone of the
extrusion is preferably less than 2 minutes and in
particular in a range between 30 seconds and 1 minute.
The actual compaction process takes place preferably at
temperatures which at least in the compaction step
correspond at least to the temperature of the softening
point, if not indeed to the temperature of the melting
point, of the binder. In one preferred embodiment of
the invention, the process temperature is significantly
above the melting point, or above the temperature at
which the binder is in melt form. In particular,
however, it is preferred for the process temperature in
the compaction step to be not more than 20°C above the
melting point, or the upper limit of the melting range,
of the binder. Although in technical terms it is
entirely possible to set even higher temperatures, it
has been found that a temperature difference from the
melting point or softening temperature of the binder of
20°C is generally entirely adequate and that higher
temperatures bring about no additional advantages.
Consequently, not least for reasons of energy, it is
particularly preferred to operate certainly above but
at least as close as possible to the melting point or
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to the upper temperature limit of the melting range of
the binder. A temperature regime of this kind possesses
the further advantage that it allows heat-sensitive raw
materials, for example, peroxy bleaches such as
perborate and/or percarbonate, and also enzymes, to be
processed increasingly without serious losses of active
substance. The possibility of precise temperature
control of the binder, especially in the decisive step
of compaction, i.e., between the mixing/homogenizing of
the premix and the shaping operation, permits a process
regime which is very favorable from an energy
standpoint and also extremely gentle for the heat-
sensitive constituents of the premix, since the premix
is exposed to the higher temperatures only for a short
time. In preferred press agglomeration processes, the
working tools of the press agglomerator (the screws)
of the extruder, the rolls) of the roll compactor, and
the rolls) of the pellet press) have a temperature of
not more than 150°C, preferably not more than 100°C,
and in particular not more than 75°C, and the process
temperature is not more than 30°C, and in particular
not more than 20°C, above the melting temperature or
the upper temperature limit of the melting range of the
binder. Preferably, the duration of temperature
exposure in the compression zone of the press
agglomerators is not more than 2 minutes and is in
particular in a range between 30 seconds and 1 minute.
Preferred binders, which may be used alone or in a
mixture with other binders, are polyethylene glycols,
1,2-polypropylene glycols, and modified polyethylene
glycols and polypropylene glycols. Modified
polyalkylene glycols include in particular the sulfates
and/or the disul.fates of polyethylene glycols or
polypropylene glycols having a relative molecular mass
of between 600 and 12,000 and in particular between
1000 and 4000. A further group consists of mono- and/or
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disuccinates of the polyalkylene glycols, which in turn
have relative molecular masses of between 600 and 6000,
preferably between 1000 and 4000. For a more precise
description of the modified polyalkylene glycol ethers,
reference is made to the disclosure content of
International Patent Application WO-A-93/02176. In the
context of this invention, polyethylene glycols include
those polymers prepared using not only ethylene glycol
but also C3-CS glycols and also glycerol and mixtures of
these as starting molecules. Also embraced are
ethoxylated derivatives such as trimethylolpropane
containing from 5 to 30 EO. The polyethylene glycols
used with preference may have a linear or branched
structure, particular preference being given to linear
polyethylene glycols. The particularly preferred
polyethylene glycols include those having relative
molecular masses of between 2000 and 12,000,
advantageously around 4000, it being possible to use
polyethylene glycols having relative molecular masses
of less than 3500 and above 5000 in particular in
combination with polyethylene glycols having a relative
molecular mass of around 4000, and such combinations
advantageously comprising more than 50~ by weight,
based on the overall amount of the polyethylene
glycols, of polyethylene glycols having a relative
molecular mass of between 3500 and 5000. The binders
used may also, however, include polyethylene glycols
which per se are in the liquid state at room
temperature under a pressure of 1 bar; this is a
reference in particular to polyethylene glycol having a
relative molecular mass of 200, 400, and 600. However,
these inherently liquid polyethylene glycols should be
used only in a mixture with at least one further
binder, which mixture must in turn satisfy the
requirements of the invention - that is, it must have a
melting point or softening point of at least above
45°C.
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Further suitable binders include low molecular mass
polyvinylpyrrolidones and derivatives thereof having
relative molecular masses of up to a maximum of 30,000.
Preference is given here to relative molecular mass
ranges between 3000 and 30,000, for example, around
10,000. Polyvinylpyrrolidones are preferably used not
as sole binders but instead in combination with others,
especially in combination with polyethylene glycols.
Further binders which have been found suitable are raw
materials having detersive properties, i.e., for
example, nonionic surfactants having melting points of
at least 45°C or mixtures of nonionic surfactants and
other binders. Preferred nonionic surfactants include
alkoxylated fatty alcohols or oxo alcohols, especially
C12-C1$ alcohols. In this context, degrees of
alkoxylation, especially degrees of ethoxylation, of on
average from 18 to 80 AO, in particular EO, per mole of
alcohol and mixtures thereof have proven particularly
advantageous. In particular, fatty alcohols containing
on average from 18 to 35 EO, especially those
containing on average from 20 to 25 EO, exhibit
advantageous binder properties in the sense of the
present invention. If desired, binder mixtures may also
include ethoxylated alcohols containing on average
fewer EO units per mole of alcohol, for example, tallow
fatty alcohol containing 14 EO. However, it is
preferred to use these alcohols having relatively low
degrees of ethoxylation only in the form of a mixture
with alcohols having higher degrees of ethoxylation.
Advantageously, the amount of these alcohols having
relatively low degrees of ethoxylation in the binders
is less than 50~ by weight, in particular less than 40°s
by weight, based on the overall amount of binder
employed. In particular, nonionic surfactants commonly
used in laundry detergents or cleaning products, such
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as C12-C1a alcohols having on average from 3 to 7 EO,
which are inherently liquid at room temperature, are
preferably present in the binder mixtures only in
amounts so as to provide less than 2~ by weight of
these nonionic surfactants, based on the process end
product. As already described above, however, it is
less preferred to use nonionic surfactants which are
liquid at room temperature in the binder mixtures. In
one particularly advantageous embodiment, however, such
nonionic surfactants are not included in the binder
mixture, since they not only reduce the softening point
of the mixture but may also contribute to tackiness in
the end product and, furthermore, fail to
satisfactorily meet the requirement of rapid
dissolution of the binder/partition wall in the end
product, owing to their tendency to cause gelling on
contact with water. Similarly, it is not preferred for
anionic surfactants or their precursors, the anionic
surfactant acids, commonly used in laundry detergent or
cleaning products to be present in the binder mixture .
Other nonionic surfactants suitable as binders are the
fatty acid methyl ester ethoxylates, which have no
gelling tendency, especially those containing on
average from 10 to 25 EO (for a more detailed
description of this group of substances, see below).
Particularly preferred representatives of this group of
substances are methyl esters based predominantly on Cls-
C1$ fatty acids, for example, hydrogenated beef tallow
methyl ester containing on average 12 EO or containing
on average 20 EO. In one preferred embodiment of the
invention, the binder used is a mixture comprising Clz-
Cl8 fatty alcohol based on coconut or tallow containing
on average 20 EO and polyethylene glycol having a
relative molecular mass of from 400 to 4000. In another
preferred embodiment of the invention, the binder used
is a mixture which comprises methyl esters based
predominantly on C16-C1$ fatty acids and containing on
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average from 10 to 25 EO, especially hydrogenated beef
tallow methyl ester containing on average 12 EO or on
average 20 EO, and a C12-C18 fatty alcohol based on
coconut or tallow containing on average 20 EO and/or
polyethylene glycol having a relative molecular mass of
from 400 to 4000.
Embodiments of the invention that have proven
particularly advantageous are binders based,
alternatively, solely on polyethylene glycols having a
relative molecular mass of around 4000, or on a mixture
of C12-C1$ fatty alcohol based on coconut or tallow and
containing on average 20 EO, and one of the above-
described fatty acid methyl ester ethoxylates, or on a
mixture of C12-C18 fatty alcohol based on coconut or
tallow and containing on average ~20 EO, one of the
above-described fatty acid methyl ester ethoxylates,
and a polyethylene glycol, especially one having a
relative molecular mass of around 4000.
In small amounts, further suitable substances in
addition to those mentioned above may also be present
in the binder.
The composition or process of the invention may be used
with water of any desired hardness. The major
constituents of water hardness are salts of calcium and
magnesium, especially chlorides, sulfates, and
bicarbonates. Since under heat the bicarbonates are
converted into carbonates, when the water is heated
some of the calcium salts are precipitated in the form
of CaC03, whose solubility is poor. At very high
magnesium concentrations, basic magnesium carbonates
may also be precipitated. The hardness or total
hardness of the water is understood as referring to the
alkaline earth metal ion content. To characterize a
water, and its hardness, the concept of degree of
CA 02315889 2000-08-14
19
hardness was introduced (°d, formerly °dH [German
hardness]): 1°d corresponds (per liter) to 10.00 mg of
Ca0 or 7.19 mg of MgO. It is also customary to state
the number of millimoles per liter (mmol/1). In this
case, the following ranges of hardness are
distinguished:
1 soft < 7°d < 1.3 mmol/1
2 moderately hard 7-14°d 1.3-2.5 mmol/1
3 hard 14-21°d 2.5-3.8 mmol/1
4 very hard > 21°d > 3.8 mmol/1
The harder the water used, the greater, generally, the
tendency to form deposits on heating rods. Accordingly,
the composition or process of the invention is used
preferably with hard or very hard water, i.e., water
having a hardness of at least 14°d; however, the
advantages of the composition or process are also
evident even with soft and moderately hard water.
In the process which comprises the washing of textiles,
the use of a laundry detergent as well is preferred. It
may be preferable for the polymeric polycarboxylate and
the water softener to be present in the laundry
detergent, the polymer being used preferably in amounts
of from 0.1 to 15% by weight, in particular from 0.5 to
10, and with particular preference from 2 to 5% by
weight, and no other, separate water-softening agent
being used.
In an alternative process, which is likewise in
accordance with the invention, the polymeric poly-
carboxylate is present in a separately added water
softener, which preferably also comprises the inorganic
softener constituents used in the process, and is
preferably dosed such that, based on the additionally
used laundry detergent, the polycarboxylate is used in
CA 02315889 2000-08-14
20
amounts of from 0.1 to 15% by weight, in particular
from 0.5 to 10, and with particular preference from 2
to 5% by weight. The polymer may be added at the same
time as the laundry detergent. Alternatively, the
polymer may be added prior to the addition of the
laundry detergent, such that the laundry detergent is
added subsequently to water pretreated with the
polymer. It is also conceivable for the polymers to be
added to the wash liquor after the laundry detergent
has been added, but with this subsequent dosing taking
place before the wash liquor is heated.
In accordance with the invention, in the process,
inorganic constituents are used for water softening.
These constituents comprise, in particular, crystalline
aluminosilicates and alkali metal carbonates. The
invention, accordingly, further provides a water
softener comprising a) from 0.1 to 30% by weight of
polymeric polycarboxylate having a molecular mass of
less than 4000 g/mol as measured by means of GPC
against polyacrylate standard, b) from 1 to 60% by
weight of zeolite, and c) from 1 to 60% by weight of
alkali metal carbonate, the sum of the constituents a),
b) and c) making up at least 90% by weight of the
overall water softener.
In a preferred composition, the water softener
comprises component a) in amounts of from 0.5 to 15% by
weight, in particular from 2 to 10% by weight, and
component b) in amounts of from 10 to 50% by weight, in
particular from 15 to 45% by weight, and component c)
in amounts of from 10 to 50% by weight, in particular
from 15 to 45% by weight, based in each case on the
overall water softener.
Preferred crystalline aluminosilicates are the zeolites
A, P, X and Y. Also suitable, however, are mixtures of
CA 02315889 2000-08-14
21
A, X, Y and/or P. As zeolite P, particular preference
is given, for example, to zeolite MAP (for example,
Doucil A24~; commercial product from Crosfield). Also
of particular interest is a cocrystallized
sodium/potassium aluminum silicate comprising zeolite A
and zeolite X, which is available commercially as
VEGOBOND AX~ (commercial product from Condea Augusta
S.p.A.). The zeolite may be used as a spray-dried
powder or else as an undried, stabilized suspension
still wet from its preparation. Where the zeolite is
used as a suspension, the suspension may include small
additions of nonionic surfactants as stabilizers, for
example, from 1 to 3% by weight, based on zeolite, of
ethoxylated C12-Cla fatty alcohols having 2 to
5 ethylene oxide groups, C1z-C14 fatty alcohols having
4 to 5 ethylene oxide groups, or ethoxylated
isotridecanols. Appropriate zeolites have an average
particle size of less than 10 ~m (volume distribution;
measurement method: Coulter counter) and contain
preferably from 10 to 22% by weight, in particular from
15 to 22% by weight, of bound water. In one preferred
embodiment of the process, laundry detergents are used
which comprise at least part of the crystalline
aluminosilicate in the form of zeolite A. In another
advantageous embodiment, at least part of the zeolite
used, preferably at least 20% by weight, comprises
faujasite-type zeolite. In the context of the present
invention, the term "faujasite-type zeolite"
characterizes all three zeolites which form the
faujasite subgroup of zeolite structural group 4. As
well as zeolite X, therefore, it is possible in
accordance with the invention to use zeolite Y and
faujasite and also mixtures of these compounds,
preference being given to straight zeolite X.
The alkali metal carbonates comprise preferably sodium
and/or potassium carbonate, the use of sodium carbonate
CA 02315889 2000-08-14
22
being preferred in particular. Alkali metal carbonate
need not necessarily be used directly but may also be
provided by precursors which do not form alkali metal
carbonate until during the process. In this respect
mention may be made, in particular, of alkali metal
percarbonate, which releases alkali metal carbonate
under the influence of moisture. Preferred in
accordance with the invention is the conjoint use of
zeolite and sodium carbonate, the weight ratio in which
the crystalline aluminosilicate and the alkali metal
carbonate are used being in the range from 1:5 to 5:1,
with particular preference in the range from 1:2 to
2:1. It may be preferable for the compositions to
comprise alkali metal carbonate in at least the same
amount as crystalline aluminosilicates, since
compositions of this kind possess advantages in their
graying inhibitor activity, have been found from
experience to have a higher bulk density, and in
addition exhibit a greater alkali reserve.
Furthermore, the compositions of the invention and,
respectively, the laundry detergents or water softeners
used in the process may comprise further builder
substances.
In particular, in addition to the polycarboxylate, they
may also comprise the copolymeric polycarboxylates that
are commonly employed as cobuilders, especially those
of acrylic acid with methacrylic acid and of acrylic
acid or methacrylic acid with malefic acid. Copolymers
which have been found particularly suitable are those
of acrylic acid with malefic acid, containing from 50 to
90% by weight of acrylic acid and from 50 to 10% by
weight of malefic acid. Their relative molecular mass is
generally from 2000 to 70,000 g/mol, preferably from
20,000 to 50,000 g/mol, and in particular from 30,000
to 40,000 g/mol. To improve the solubility in water,
CA 02315889 2000-08-14
23
the polymers may also comprise allylsulfonic acids as
monomers, such as, for example, in EP-B-727448,
allyloxybenzenesulfonic acid and methallylsulfonic
acid. Particular preference is also given to
biodegradable polymers comprising more than two
different monomer units, for example, those which in
accordance with DE-A-43 00 772 comprise as monomers
salts of acrylic acid and of malefic acid and also vinyl
alcohol and/or vinyl alcohol derivatives or those
which, in accordance with DE-C-42 21 381, comprise as
monomers salts of acrylic acid and of 2-alkylallyl-
sulfonic acid, and also sugar derivatives. Further
preferred copolymers are those described in German
Patent Applications DE-A-43 03 320 and DE-A-44 17 734
and comprising as monomers preferably acrolein and
acrylic acid/acrylic acid salts or acrolein and vinyl
acetate. In one preferred variant, both these
copolymers and the polycarboxylates that are essential
to the invention are present, the ratio of the
polycarboxylate to the acrylic acid/maleic acid
copolymer being in the range from 2:1 to 1:20,
preferably from 1:1 to 1:15. The polymer content in the
compositions overall is preferably from 0.5 to 20% by
weight, in particular from 2 to 10% by weight. In
another, likewise preferred embodiment of the
invention, the process uses no polymer of acrylic acid
other than the polycarboxylate of the invention, and in
particular uses no copolymer of acrylic acid with
malefic acid either.
In addition to the substances already mentioned, the
compositions used in the process of the invention,
especially the laundry detergent, may comprise further
ingredients. Mention may be made here, for example, of
further builder substances, which are preferably
present, however, only in smaller amounts than the
CA 02315889 2000-08-14
24
abovementioned inorganic builders - zeolites and alkali
metal carbonates.
Mention may be made here of crystalline, layer-form
sodium silicates of the general formula NaMSiX02X+l~YHa~,
where M is sodium or hydrogen, x is a number from
1.9 to 4, y is a number from 0 to 20, and preferred
values for x are 2, 3 or 4. Crystalline phyllosilicates
of this kind are described, for example, in European
Patent Application EP-A-0 164 514. Preferred
crystalline phyllosilicates of the stated formula are
those where M is sodium and x adopts the value 2 or 3.
In particular, both (3- and 8-sodium disilicates
Na2Si205~yHz0 are preferred.
Furthermore, it is also possible to use amorphous
sodium silicates having an Na20:Si02 modulus of from 1:2
to 1:3.3, preferably from 1:2 to 1:2.8, and in
particular from 1:2 to 1:2.6, which are dissolution-
retarded and have secondary detergency properties, as
builders. The retarded dissolution relative to
conventional amorphous sodium silicates may have been
brought about in a variety of ways - for example, by
surface treatment, compounding, compacting, or
overdrying. In the context of this invention, the term
"amorphous" also embraces "X-ray-amorphous". This means
that in X-ray diffraction experiments the silicates do
not yield the sharp X-ray reflections typical of
crystalline substances but instead yield at best one or
more maxima of the scattered X-radiation, having a
width of several degree units of the diffraction angle.
However, good builder properties, even particularly
good builder properties, may well result if the
silicate particles in electron diffraction experiments
yield vague or even sharp diffraction maxima. The
interpretation of this is that the products have
microcrystalline regions with a size of from 10 to
CA 02315889 2000-08-14
25
several hundred nm, values up to max. 50 nm and in
particular up to max. 20 nm being preferred. So-called
X-ray-amorphous silicates of this kind, which likewise
possess retarded dissolution relative to the
conventional waterglasses, are described, for example,
in German Patent Application DE-A-44 00 024. Particular
preference is given to compacted amorphous silicates,
compounded amorphous silicates, and overdried X-ray-
amorphous silicates.
Of course, the widely known phosphates may also be used
as builder substances, provided such a use is not to be
avoided on ecological grounds. Particularly suitable
are the sodium salts of the orthophosphates, of the
pyrophosphates and, in particular, of the
tripolyphosphates.
In other, likewise preferred embodiments of the
invention, the compositions may comprise builder
systems which are substantially free from crystalline
aluminosilicates. These may, preferably, be builder
systems whose principal inorganic constituents comprise
sodium carbonate and alkali metal silicates.
Organic builder substances which may be used are, for
example, the polycarboxylic acids, usable in the form
of their sodium salts, the term polycarboxylic acids
meaning those carboxylic acids which carry more than
one acid function. Examples of these are citric acid,
adipic acid, succinic acid, glutaric acid, malic acid,
tartaric acid, malefic acid, fumaric acid, sugar acids,
amino carboxylic acids, nitrilotriacetic acid (NTA),
provided such use is not objectionable on ecological
grounds, and also mixtures of these. Preferred salts
are the salts of the polycarboxylic acids such as
citric acid, adipic acid, succinic acid, glutaric acid,
tartaric acid, sugar acids, and mixtures thereof.
CA 02315889 2000-08-14
26
The acids per se may also be used. In addition to their
builder effect, the acids typically also possess the
property of an acidifying component and thus also serve
to establish a lower and milder pH of laundry
detergents or cleaning products. In this context,
mention may be made in particular of citric acid,
succinic acid, glutaric acid, adipic acid, gluconic
acid, and any desired mixtures thereof.
Similarly, further preferred builder substances that
may be mentioned include polymeric amino dicarboxylic
acids, their salts or their precursor substances.
Particular preference is given to polyaspartic acids
and their salts and derivatives, which are disclosed in
German Patent Application DE-A-195 40 086 to have not
only cobuilder properties but also a bleach-stabilizing
action.
Further suitable builder substances are polyacetals,
which may be obtained by reacting dialdehydes with
polyol carboxylic acids having 5 to 7 carbon atoms and
at least 3 hydroxyl groups, as described, for example,
in European Patent Application EP-A-0 280 223.
Preferred polyacetals are obtained from dialdehydes
such as glyoxal, glutaraldehyde, terephthalaldehyde and
mixtures thereof and from polyol carboxylic acids such
as gluconic acid and/or glucoheptonic acid.
Further suitable organic builder substances are
dextrins, examples being oligomers and polymers of
carbohydrates, which may be obtained by partial
hydrolysis of starches. The hydrolysis may be conducted
by customary processes, for example, acid-catalyzed or
enzyme-catalyzed processes. The hydrolysis products
preferably have average molecular masses in the range
from 400 to 500, 000 g/mol . Preference is given here to
CA 02315889 2000-08-14
27
a polysaccharide having a dextrose equivalent (DE) in
the range from 0.5 to 40, in particular from 2 to 30,
DE being a common measure of the reducing effect of a
polysaccharide in comparison to dextrose, which
possesses a DE of 100. It is possible to use both
maltodextrins having a DE of between 3 and 20 and dry
glucose syrups having a DE of between 20 and 37, and
also so-called yellow dextrins and white dextrins
having higher molecular masses, in the range from 2000
to 30,000 g/mol. One preferred dextrin is described in
British Patent Application 94 19 091.
The oxidized derivatives of such dextrins comprise
their products of reaction with oxidizing agents which
are able to oxidize at least one alcohol function of
the saccharide ring to the carboxylic acid function.
Oxidized dextrins of this kind, and processes for
preparing them, are known, for example, from European
Patent Applications EP-A-0 232 202, EP-A-0 427 349,
EP-A-0 472 042, and EP-A-0 542 496, and from
International Patent Applications WO 92/18542,
WO 93/08251, WO 93/16110, WO 94/28030, WO 95/07303,
WO 95/12619, and WO 95/20608. Likewise suitable is an
oxidized oligosaccharide in accordance with German
Patent Application DE-A-196 00 018. A product oxidized
at C6 of the saccharide ring may be particularly
advantageous.
Oxydisuccinates and other derivatives of disuccinates,
preferably ethylenediamine disuccinate, are further
suitable cobuilders. Ethylenediamine N,N'-disuccinate
(EDDS), whose synthesis is described, for example, in
US 3,158,615, is used preferably in the form of its
sodium or magnesium salts. Further preference in this
context is given to glycerol disuccinates and glycerol
trisuccinates as well, as described, for example, in
U.S. Patents US 4,524,009 and US 4,639,325, in European
CA 02315889 2000-08-14
28
Patent Application EP-A-0 150 930, and in Japanese
Patent Application JP 93/339896. Suitable use amounts
in formulations containing zeolite and/or silicate are
from 3 to 15% by weight.
Examples of further useful organic cobuilders are
acetylated hydroxy carboxylic acids and their salts,
which may also be present in lactone form and which
contain at least 4 carbon atoms, at least one hydroxyl
group, and not more than two acid groups. Such
cobuilders are described, for example, in International
Patent Application WO 95/20029.
A further class of substance having cobuilder
properties is represented by the phosphonates. The
phosphonates in question are, in particular,
hydroxyalkane- and aminoalkanephosphonates. Among the
hydroxyalkanephosphonates, 1-hydroxyethane-1,1-diphos-
phonate (HEDP) is of particular importance as a
cobuilder. It is used preferably as the sodium salt,
the disodium salt reacting neutrally and the
tetrasodium salt giving an alkaline (pH 9) reaction.
Suitable aminoalkanephosphonates are preferably
ethylenediaminetetramethylenephosphonate (EDTMP),
diethylenetriaminepentamethylenephosphonate (DTPMP),
and their higher homologs . They are used preferably in
the form of neutrally reacting sodium salts, e.g., as
the hexasodium salt of EDTMP or as the hepta- and
octasodium salt of DTPMP. As a builder in this case,
preference is given to using HEDP from the class of the
phosphonates. Furthermore, the aminoalkanephosphonates
possess a pronounced heavy metal binding capacity.
Accordingly, and especially if the compositions also
contain bleach, it may be preferred to use
aminoalkanephosphonates, especially DTPMP, or to use
mixtures of said phosphonates.
CA 02315889 2000-08-14
29
Furthermore, all compounds capable of forming complexes
with alkaline earth metal ions may be used as
cobuilders.
Important further ingredients of the laundry detergents
used in the process of the invention are surfactants,
especially anionic surfactants. These include, in
particular, sulfonates and sulfates, but also soaps.
Preferred surfactants of the sulfonate type are C9-13
alkylbenzenesulfonates, olefinsulfonates, i.e.,
mixtures of alkenesulfonates and hydroxyalkane-
sulfonates, and also disulfonates, as are obtained, for
example, from Clz-is monoolefins having a terminal or
internal double bond by sulfonating with gaseous sulfur
trioxide followed by alkaline or acidic hydrolysis of
the sulfonation products.
Also suitable are alkanesulfonates, which are obtained
from Clz-is alkanes, for example, by sulfochlorination or
sulfoxidation with subsequent hydrolysis or
neutralization, respectively.
Likewise suitable, in addition, are the esters of
a-sulfo fatty acids (ester sulfonates), e.g., the
a-sulfonated methyl esters of hydrogenated coconut,
palm kernel or tallow fatty acids, which are prepared
by a-sulfonation of the methyl esters of fatty acids of
plant and/or animal origin having 8 to 20 carbon atoms
in the fatty acid molecule, followed by neutralization
to give water-soluble mono-salts. Preferably, these
comprise the a-sulfonated esters of hydrogenated
coconut, palm, palm kernel or tallow fatty acids, it
being possible as well for sulfonation products of
unsaturated fatty acids, e.g. oleic acid, to be present
in small amounts, preferably in amounts of not more
than about 2 to 3°s by weight. Particular preference is
. CA 02315889 2000-08-14
given to a-sulfo fatty acid alkyl esters having an
alkyl chain of not more than 4 carbon atoms in the
ester group, examples being methyl esters, ethyl
esters, propyl esters, and butyl esters. With
particular advantage, the methyl esters of the a-sulfo
fatty acids (MES) are used, and also their saponified
di-salts.
Further suitable anionic surfactants are sulfated fatty
acid glycerol esters which are the monoesters, diesters
and triesters, and mixtures thereof, as obtained in the
preparation by esterification of a monoglycerol with
from 1 to 3 mol of fatty acid or in the
transesterification of triglycerides with from 0.3 to 2
mol of glycerol.
Preferred alk(en)yl sulfates are the alkali metal
salts, and especially the sodium salts, of the sulfuric
monoesters of Clz-C1$ fatty alcohols, examples being
those of coconut fatty alcohol, tallow fatty alcohol,
lauryl, myristyl, cetyl or stearyl alcohol, or of
Clo-Czo oxo alcohols, and those monoesters of secondary
alcohols of these chain lengths. Preference is also
given to alk(en)yl sulfates of said chain length which
contain a synthetic straight-chain alkyl radical
prepared on a petrochemical basis, these sulfates
possessing degradation properties similar to those of
the corresponding compounds based on fatty-chemical raw
materials. From a detergents standpoint, Clz-Cis alkyl
sulfates and Clz-Cis alkyl sulfates, and also C14-Cis
alkyl sulfates, are particularly preferred. In
addition, 2,3-alkyl sulfates, which may for example be
prepared in accordance with US Patents 3,234,258 or
5,075,041 and obtained as commercial products from
Shell Oil Company under the name DAN~, are suitable
anionic surfactants.
CA 02315889 2000-08-14
31
Also suitable are the sulfuric monoesters of the
straight-chain or branched C~_zl alcohols ethoxylated
with from 1 to 6 mol of ethylene oxide, such as
2-methyl-branched C9_11 alcohols containing on average
3.5 mol of ethylene oxide (EO) or Clz-is fatty alcohols
containing from 1 to 4 EO. Because of their high
foaming they are used in laundry detergents only in
relatively small amounts, for example, in amounts of
from 1 to 5~S by weight .
Further preferred anionic surfactants include the salts
of alkylsulfosuccinic acid, which are also referred to
as sulfosuccinates or as sulfosuccinic esters and which
constitute the monoesters and/or diesters of
sulfosuccinic acid with alcohols, preferably fatty
alcohols and especially ethoxylated fatty alcohols.
Preferred sulfosuccinates comprise Ca_1s fatty alcohol
radicals or mixtures thereof. Especially preferred
sulfosuccinates contain a fatty alcohol radical derived
from ethoxylated fatty alcohols which themselves
represent nonionic surfactants (for description, see
below). Particular preference is given in turn to
sulfosuccinates whose fatty alcohol radicals are
derived from ethoxylated fatty alcohols having a
narrowed homolog distribution. Similarly, it is also
possible to use alk(en)ylsuccinic acid containing
preferably 8 to 18 carbon atoms in the alk(en)yl chain,
or salts thereof.
Further suitable anionic surfactants include fatty acid
derivatives of amino acids, for example, of N-methyl-
taurine (taurides) and/or of N-methylglycine
(sarcosides). Particular preference is given here to
sarcosides and to the sarcosinates and, of these,
especially the sarcosinates of higher fatty acids,
which may be mono- or polyunsaturated, such as oleyl
sarcosinate.
CA 02315889 2000-08-14
32
Further suitable anionic surfactants are, in
particular, soaps, preferably in amounts of from 0.2 to
5% by weight. Suitable soaps include in particular
saturated fatty acid soaps, such as the salts of lauric
acid, myristic acid, palmitic acid, stearic acid,
hydrogenated erucic acid and behenic acid, and, in
particular, mixtures of soaps derived from natural
fatty acids, e.g., coconut, palm kernel, or tallow
fatty acids. Together with these soaps, or as
substitutes for soaps, it is also possible to use the
known alkenylsuccinic salts.
The anionic surfactants, including the soaps, may be
present in the form of their sodium, potassium or
ammonium salts and also as soluble salts of organic
bases, such as mono-, di- or triethanolamine.
Preferably, the anionic surfactants are in the form of
their sodium or potassium salts, in particular in the
form of the sodium salts.
The anionic surfactants are present in the compositions
of the invention, and are used in the process of the
invention, in amounts of preferably from 1 to 30% by
weight, in particular in amounts from 5 to 25% by
weight.
In addition to the anionic surfactants and the
cationic, zwitterionic and amphoteric surfactants,
particular preference is given to nonionic surfactants.
Nonionic surfactants used are preferably alkoxylated,
advantageously ethoxylated, especially primary,
alcohols having preferably 8 to 18 carbon atoms and on
average from 1 to 12 mol of ethylene oxide (EO) per
mole of alcohol, in which the alcohol radical may be
linear or, preferably, methyl-branched in position 2
CA 02315889 2000-08-14
33
and/or may comprise linear and methyl-branched radicals
in a mixture, as are commonly present in oxo alcohol
radicals. In particular, however, preference is given
to alcohol ethoxylates containing linear radicals from
alcohols of natural origin having 12 to 18 carbon
atoms, e.g., from coconut, palm, tallow fatty or oleyl
alcohol and on average from 2 to 8 EO per mole of
alcohol. Preferred ethoxylated alcohols include, for
example, C12-14 alcohols containing 3 EO or 4 EO, C9_11
alcohols containing 7 EO, C13-is alcohols containing 3
EO, 5 EO, 7 EO or 8 EO, C12_la alcohols containing 3 EO,
5 EO or 7 EO, and mixtures thereof, such as mixtures of
C12-14 alcohol containing 3 EO and Cla-18 alcohol
containing 7 EO. The stated degrees of ethoxylation
represent statistical mean values, which for a specific
product may be an integer or a fraction. Preferred
alcohol ethoxylates have a narrowed homolog
distribution (narrow range ethoxylates, NREs). In
addition to these nonionic surfactants it is also
possible, as described above, to use fatty alcohols
containing more than 12 EO. Examples thereof are
(tallow) fatty alcohols containing 14 EO, 16 EO, 20 EO,
25 EO, 30 EO or 40 EO.
The nonionic surfactants also include alkyl glycosides
of the general formula RO(G)X, where R is a primary
straight-chain or methyl-branched aliphatic radical,
especially an aliphatic radical methyl-branched in
position 2, containing 8 to 22, preferably 12 to 18,
carbon atoms, and G is the symbol representing a
glycose unit having 5 or 6 carbon atoms, preferably
glucose. The degree of oligomerization, x, which
indicates the distribution of monoglycosides and
oligoglycosides, is any desired number - which, as a
variable to be determined analytically, may also be a
fraction - between 1 and 10; preferably, x is from 1.2
to 1.4.
CA 02315889 2000-08-14
34
Further suitable surfactants are polyhydroxy fatty acid
amides of the formula (I)
Rz
R1-CO-N- [Z] ( I ) ,
where R1C0 is an aliphatic aryl radical having 6 to 22
carbon atoms, R2 is hydrogen or an alkyl or
hydroxyalkyl radical having 1 to 4 carbon atoms, and
[Z] is a linear or branched polyhydroxyalkyl radical
having 3 to 10 carbon atoms and from 3 to 10 hydroxyl
groups. The polyhydroxy fatty acid amides are derived
preferably from reducing sugars having 5 or 6 carbon
atoms, especially glucose. The group of the polyhydroxy
fatty acid amides also includes compounds of the
formula (II)
Ra-O-Rs
R3-CO-N- [Z] (II) ,
where R3 is a linear or branched alkyl or alkenyl
radical having 7 to 12 carbon atoms, R4 is a linear,
branched or cyclic alkylene radical or an arylene
radical having 2 to 8 carbon atoms and RS is a linear,
branched or cyclic alkyl radical or an aryl radical or
an oxyalkyl radical having 1 to 8 carbon atoms,
preference being given to C1-C4 alkyl radicals or phenyl
radicals, and [Z] is a linear polyhydroxyalkyl radical
whose alkyl chain is substituted by at least two
hydroxyl groups, or alkoxylated, preferably ethoxylated
or propoxylated, derivatives of said radical. Here too,
[Z] is preferably obtained by reductive amination of a
sugar, e.g., glucose, fructose, maltose, lactose,
galactose, mannose, or xylose. The N-alkoxy or
CA 02315889 2000-08-14
N-aryloxy-substituted compounds may then be converted
to the desired polyhydroxy fatty acid amides, for
example, in accordance with the teaching of
International Patent Application WO 95/07331 by
reaction with fatty acid methyl esters in the presence
of an alkoxide as catalyst.
A further class of nonionic surfactants used with
preference, which are used either as sole nonionic
surfactant or in combination with other nonionic
surfactants, in particular together with alkoxylated
fatty alcohols and/or alkyl glycosides, are
alkoxylated, preferably ethoxylated, or ethoxylated and
propoxylated, fatty acid alkyl esters, preferably
having 1 to 4 carbon atoms in the alkyl chain,
especially fatty acid methyl esters, as are described,
for example, in Japanese Patent Application
JP 58/217598, or those prepared preferably by the
process described in International Patent Application
WO-A-90/13533. Preferred nonionic surfactants are
C12-Cla fatty acid methyl esters containing on average
from 3 to 15 EO, in particular containing on average
from 5 to 12 EO, whereas fatty acid methyl esters with
higher degrees of ethoxylation are particularly
advantageous - as described above - as binders.
Especially C12-C1$ fatty acid methyl esters containing
from 10 to 12 EO may be used both as surfactants and as
binders.
Nonionic surfactants of the amine oxide type, examples
being N-cocoalkyl-N,N-dimethylamine oxide and N-tallow-
alkyl-N,N-dihydroxyethylamine oxide, and of the fatty
acid alkanolamide type, may also be suitable. The
amount of these nonionic surfactants is preferably not
more than that of the ethoxylated fatty alcohols, in
particular not more than half thereof.
CA 02315889 2000-08-14
36
Further suitable surfactants include those known as
Gemini surfactants. This term is used generally to
refer to those compounds which possess two hydrophilic
groups and two hydrophobic groups per molecule. These
groups are generally separate from one another as a
result of what is known as a spacer. This spacer is
generally a carbon chain, which should be long enough
to give the hydrophilic groups a sufficient spacing to
allow them to act independently of one another.
Surfactants of this kind are generally notable for an
unusually low critical micelle concentration and the
ability to reduce greatly the surface tension of water.
In exceptional cases, however, the expression Gemini
surfactants is used to embrace not only dimeric but
also trimeric surfactants.
Examples of suitable Gemini surfactants are sulfated
hydroxy mixed ethers in accordance with German Patent
Application DE-A-43 21 022 or dimer alcohol bis- and
trimer alcohol tris-sulfates and ether sulfates in
accordance with German Patent Application DE-A-195 03
061. Endgroup-capped dimeric and trimeric mixed ethers
in accordance with German Patent Application DE-A-195
13 391 are notable in particular for their bi- and
multifunctionality. Thus said endgroup-capped
surfactants possess good wetting properties and are low
in foam, so making them particularly suitable for use
in machine washing or cleaning processes.
However, it is also possible to use gemini-polyhydroxy
fatty acid amides or poly-polyhydroxy fatty acid
amides, as described in International Patent
Applications WO-A-95/19953, WO-A-95/19954, and
WO-A-95/19955.
In addition to the surfactants, the compositions may
also include components which promote the removal of
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oils and fats from textiles by washing. This effect is
particularly marked if a textile which has already been
washed a number of times before with a laundry
detergent of the invention comprising said oil- and
fat-dissolving component becomes soiled. Examples of
preferred oil- and fat-dissolving components include
nonionic cellulose ethers such as methylcellulose and
methylhydroxypropylcellulose containing from 15 to 30~
by weight methoxy groups and from 1 to 15~ by weight
hydroxypropoxy groups, based in each case on the
nonionic cellulose ether, and also the prior art
polymers of phthalic acid and/or terephthalic acid
and/or derivatives thereof, especially polymers of
ethylene terephthalates and/or polyethylene glycol
terephthalates, or their anionically and/or non-
ionically modified derivatives. Among these, particular
preference is given to the sulfonated derivatives of
phthalic acid polymers and of terephthalic acid
polymers.
The other constituents of laundry detergents include
graying inhibitors (antiredeposition agents), foam
inhibitors, bleaches, bleach activators, optical
brighteners, enzymes, fabric softeners, dyes,
fragrances, and also neutral salts such as sulfates and
chlorides in the form of their sodium salts or
potassium salts.
To lower the pH of laundry detergents or cleaning
products it is also possible to use acidic salts or
slightly alkaline salts. As acidifying component,
preference is given in this context to bisulfates
and/or bicarbonates or to the abovementioned organic
polycarboxylic acids which may also be used as builder
substances at the same time. Particular preference is
given to the use of citric acid.
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Among the compounds which act as bleaches and which in
water produce HZO2, particular importance is possessed
by sodium perborate tetrahydrate, sodium perborate
monohydrate, and sodium percarbonate. Further bleaches
that may be used are, for example, peroxy pyro-
phosphates, citrate perhydrates, and H20z-donating
peracidic salts or peracids, such as perbenzoates,
peroxophthalates, diperazelaic acids, phthaloiminoper-
acid, or diperdodecanedioic acid.
Bleach activators which may be used are compounds which
under perhydrolysis conditions give rise to aliphatic
peroxo carboxylic acids having preferably 1 to 10
carbon atoms, in particular 2 to 4 carbon atoms, and/or
substituted or unsubstituted perbenzoic acid. Suitable
substances are those which carry O-acyl and/or N-acyl
groups of the stated number of carbon atoms, and/or
substituted or unsubstituted benzoyl groups. Preference
is given to polyacylated alkylenediamines, especially
tetraacetylethylenediamine (TAED), acylated triazine
derivatives, especially 1,5-diacetyl-2,4-dioxohexa-
hydro-1,3,5-triazine (DADHT), acylated glycolurils,
especially tetraacetylglycoluril (TAGU), N-acyl imides,
especially N-nonanoylsuccinimide (NOSI), acylated
phenolsulfonates, especially n-nonanoyl- or
isononanoyloxybenzenesulfonate (n- or iso-NOBS),
carboxylic anhydrides, especially phthalic anhydride,
acylated polyhydric alcohols, especially triacetin,
ethylene glycol diacetate, 2,5-diacetoxy-2,5-dihydro-
furan, and the enol esters known from German Patent
Applications DE-A-196 16 693 and DE-A-196 16 767, and
also acetylated sorbitol and mannitol and/or the
mixtures thereof described in European Patent
Application EP-A-0 525 239 (SORMAN), acylated sugar
derivatives, especially pentaacetylglucose (PAG),
pentaacetylfructose, tetraacetylxylose and octaacetyl-
lactose, and acetylated, optionally N-alkylated
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glucamine and gluconolactone, and/or N-acylated
lactams, for example, N-benzoylcaprolactam. Hydro-
philically substituted acylacetals known from German
Patent Application DE-A-196 16 769 and acyllactams
described in German Patent Application DE-A-196 16 770
and in International Patent Application WO-A-95/14075
are likewise used with preference. Combinations of
conventional bleach activators, known from German
Patent Application DE-A-44 43 177, may also be used.
These bleach activators are in customary quantities,
preferably in amounts of from 1 to 10~s by weight, and
in particular from 2 to 8~ by weight, based on the
overall composition.
In addition to the conventional bleach activators, or
instead of them, it is also possible to incorporate
what are known as bleaching catalysts into the tablets.
These substances are bleach-boosting transition metal
salts or transition metal complexes such as, for
example, Mn-, Fe-, Co-, Ru- or Mo-salen complexes or
-carbonyl complexes. Other bleaching catalysts which
can be used include Mn, Fe, Co, Ru, Mo, Ti, V and Cu
complexes with N-containing tripod ligands, and also
Co-, Fe-, Cu- and Ru-amine complexes.
For use in machine washing processes, it may be of
advantage to add customary foam inhibitors to the
compositions. Examples of suitable foam inhibitors are
soaps of natural or synthetic origin having a high
Cie-C24 fatty acid fraction. Examples of suitable
nonsurfactant-type foam inhibitors are organo-
polysiloxanes and their mixtures with microfine,
optionally silanized silica and also paraffins, waxes,
microcrystalline waxes, and mixtures thereof with
silanized silica or bistearylethylenediamide. With
advantages, use is also made of mixtures of different
foam inhibitors, for example, mixtures comprising
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silicones, paraffins, or waxes. The foam inhibitors,
especially those containing silicone and/or paraffin,
are preferably bound on a granular, water-soluble or
water-dispersible support substance. Particular
preference is given in this context to mixtures of
paraffins and bistearylethylenediamides.
Suitable enzymes include in particular those from the
class of the hydrolases, such as the proteases, lipases
or lipolytic enzymes, amylases, cellulases, and
mixtures thereof. Oxireductases are also suitable.
Especially suitable enzymatic active substances are
those obtained from bacterial strains or fungi, such as
Bacillus subtilis, Bacillus licheniformis, Streptomyces
griseus and Humicola insolens. Preference is given to
the use of proteases of the subtilisin type, and
especially to proteases obtained from Bacillus lentus.
Of particular interest in this context are enzyme
mixtures, examples being those of protease and amylase
or protease and lipase or lipolytic enzymes, or
protease and cellulase, or of cellulase and lipase or
lipolytic enzymes, or of protease, amylase and lipase
or lipolytic enzymes, or protease, lipase or lipolytic
enzymes and cellulase, but especially protease- and/or
lipase-containing mixtures or mixtures with lipolytic
enzymes. Examples of such lipolytic enzymes are the
known cutinases. Peroxidases or oxidases have also
proven suitable in certain cases. The suitable amylases
include, in particular, a-amylases, iso-amylases,
pullulanases, and pectinases. Cellulases used are
preferably cellobiohydrolases, endoglucanases and
~-glucosidases, which are also called cellobiases, and
mixtures of these. Since the various types of cellulase
differ in their CMCase and Avicelase activities, the
desired activities may be established by means of
specific mixtures of the cellulases.
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The enzymes may be adsorbed on carrier substances
and/or embedded in coating substances in order to
protect them against premature decomposition. The
proportion of the enzymes, enzyme mixtures or enzyme
granules may be, for example, from about 0.1 to 5% by
weight, preferably from 0.1 to about 2% by weight.
In addition to phosphonates, the compositions may
include further enzyme stabilizers. For example, from
0.5 to 1% by weight of sodium formate may be used. Also
possible is the use of proteases, which are stabilized
with soluble calcium salts and with a calcium content
of preferably about 1.2% by weight, based on the
enzyme. As well as calcium salts, magnesium salts also
serve as stabilizers. Particularly advantageous,
however, is the use of boron compounds, for example, of
boric acid, boron oxide, borax and other alkali metal
borates such as the salts of orthoboric acid (H3B03), of
metaboric acid (HB02), and of pyroboric acid
(tetraboric acid H2B40~) .
Graying inhibitors have the function of keeping the
dirt detached from the fiber in suspension in the
liquor and so preventing the redeposition of the dirt.
Suitable for this purpose are water-soluble colloids,
usually organic in nature, examples being the water-
soluble salts of polymeric carboxylic acids, glue,
gelatin, salts of ethercarboxylic acids or ether-
sulfonic acids of starch or of cellulose or salts of
acidic sulfuric esters of cellulose or of starch.
Water-soluble polyamides containing acidic groups are
also suitable for this purpose. Furthermore, soluble
starch preparations, and starch products other than
those mentioned above, may be used, examples being
degraded starch, aldehyde starches, etc. Polyvinyl-
pyrrolidone may also be used. Preference, however, is
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given to the use of cellulose ethers, such as carboxy-
methylcellulose (Na salt), methylcellulose, hydroxy-
alkylcellulose and mixed ethers, such as methylhydroxy-
ethylcellulose, methylhydroxypropylcellulose, methyl-
carboxymethylcellulose and mixtures thereof, and also
polyvinylpyrrolidone, for example, in amounts of from
0.1 to 5°s by weight, based on the compositions.
As optical brighteners, the compositions may include
derivatives of diaminostilbenedisulfonic acid and/or
its alkali metal salts. Suitable, for example, are
salts of 4,4'-bis(2-anilino-4-morpholino-1,3,5-
triazinyl-6-amino)stilbene-2,2'-disulfonic acid or
compounds of similar structure which instead of the
morpholino group carry a diethanolamino group, a
methylamino group, an anilino group, or a 2-
methoxyethylamino group. It is also possible for
brighteners of the substituted diphenylstyryl type to
be present, for example, the alkali metal salts of
4,4'-bis(2-sulfostyryl)biphenyl, 4,4'-bis(4-chloro-3-
sulfostyryl)biphenyl, or 4-(4-chlorostyryl)-4'-(2-
sulfostyryl)biphenyl. Mixtures of the aforementioned
brighteners may also be used.
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Exams es
Laundry detergents of the invention were prepared by
first preparing a base laundry detergent in an
extrusion process and then admixing the bleach granules
and also enzyme granules and TAED granules to said base
detergent.
The resultant detergents contained 16% by weight of a
3:1 mixture of sodium alkylbenzenesulfonate and fatty
alcohol sulfate, 5% by weight of fatty alcohol
ethoxylate, 0.7% by weight of soap, 25% by weight of
zeolite NaA, 0.3% by weight of phosphonate, 3% by
weight of citrate, 4% by weight of polymeric
polycarboxylate, 3% by weight of sodium carbonate, 17%
by weight of sodium percarbonate, 7% by weight of TAED
and other auxiliaries. The detergents contained
polymeric polycarboxylates in accordance with Table 1
and, to make them up to 100% by weight, water, salts
and other laundry detergent ingredients (for example,
defoamers, dyes, enzymes) used in small amounts.
The included Sokalan CP5 was incorporated basically by
way of the premix. While the short-chain polyacrylate
in E1 was admixed to the extruded base detergent after
extrusion, the short-chain polyacrylate in E2 was
likewise added to the premix prior to extrusion. The
resultant coarse-particled detergents have average
particle sizes of the order of 1.4 mm and bulk
densities of between 750 and 800 g/1.
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Table 1: Polymeric polycarboxylates in the laundry
detergents prepared (type and ~ by weight based on the
overall composition)
V1 E1 E2
Sokalan CP5 4.0 3.7 3.7
Sokalan PA30 - 0.3 -
PA 2500 - - 0.3
Sokalan CP5~. Acrylic acid-malefic acid copolymer;
M = 70,000 g/mol; commercial product
f rom BASF
Sokalan PA30~. Polyacrylic acid, sodium salt;
M = 4500 g/mol; commercial product from
BASF
PA 2500: Polyacrylic acid, Na salt,
M = 2500 g/m01; MW/Mn = 7
To investigate the heating rod deposits, a 10 1
stainless steel vessel with a heating rod suspended in
it was used. The initial charge in each case comprised
1 of mains water of hardness 30°d (Ca:Mg=5:1).
Following the addition of 40 g of the respective
formulation, the temperature was raised from room
temperature to 90°C over the course of 60 minutes, in a
time/temperature program, and this temperature was held
for 30 minutes. Subsequently, the liquor was drained
off and loose adhering deposits were rinsed off with
mains water. After 10 such cycles, the deposits present
on the heating rods were removed completely with citric
acid solution and/or alkaline EDTA solution and were
analyzed for CaO, MgO, Si02, and A1203 components by
means of ICP (JY70 Plus; Instruments S.A.).
_ CA 02315889 2000-08-14
Table 2: Heating rod deposits [mg]
Test Ca0 [mg] Mg0 [mg] SiOz A1z03 Total
[mg] [mg] [mg]
V1 190 100 130 110 530
El 190 84 120 100 494
E2 9 18 6 5 38
It was found that by using polymeric polycarboxylates
having molecular masses below 10,000 g/mol in
particulate extruded laundry detergents it was possible
to achieve an overall reduction in the amount of
deposit. In the case of E1, the amount of overall
deposition was already markedly reduced in comparison
to V1. The effect becomes extremely marked in the case
of E2, where a polymeric polycarboxylate having a
molecular mass of less than 4000 g/mol was used in the
premix. In this case, the amount of deposition
underwent overall reduction by a factor of more than
10.
