Note: Descriptions are shown in the official language in which they were submitted.
_ CA 02300786 2000-03-16
Anionic Surfactant Granules
This invention relates to anionic surfactant granules for use in
detergents.
Anionic surfactants based on alkyl sulfates, more particularly alkali
metal salts of alkyl sulfate, especially fatty alcohol sulfates (FAS), are of
considerable importance in the building of laundry detergent formulations.
These anionic surfactants, which are solid in their dry state, are widely
used basic constituents of laundry detergents in combination with nonionic
surfactant compounds.
FAS-based anionic surfactants are, in particular, the sodium salts of
esters of sulfuric acid with fatty alcohols of natural and/or synthetic origin
with a suitable chain length. Particular significance attaches to the
derivatives based on natural materials which are known to be distinguished
by their straight-chain fatty alcohol radicals and by the particular
ecological
compatibility associated therewith. Suitable FAS components with an
anionic surfactant effect are, in particular, the corresponding fatty alcohol
derivatives where the fatty alcohol radicals have a chain length of 10 to 22
carbon atoms and, more particularly, 12 to 18 carbon atoms.
The detersive activity of the individual members of this series of FAS
compounds in question here has been the subject of numerous
investigations and publications. Two of the many parameters investigated
in this connection - which develop in opposite directions with increasing
numbers of carbon atoms in the linear alkyl chain and which can therefore
represent an unwanted obstacle to or rather restriction of this class of
anionic surfactants - are relevant to the understanding of the teaching
according to the present invention.
The solubility of the FAS sodium salts decreases with increasing
chain length, particularly at relatively low washing temperatures, for
CA 02300786 2000-03-16
2
example in the range from about 20 to 40°C. On the other hand, however,
the detersive properties of these anionic surfactants increase with
increasing numbers of carbon atoms in the fatty alcohol radicals. The use
of FAS components based on saturated fatty alcohols containing 16118
carbon atoms is particularly desirable from the point of view of washing
technology and particularly from the point of view of the required cleaning
of laundry. Considerable practical difficulties arise in the application of
this
approach on account of the poor solubility of these components,
particularly at the relatively low wash liquor temperatures mentioned. With-
out any claim to completeness, it may be said that the dissolution of
corresponding surfactant-containing preparations in the cold wash liquor
generally present in domestic washing machines in the detergent
dispensing cycle presents difficulties. On account of the high Krafft points
of the C~s,~B FAS anionic surfactants particularly affected here, no micelles
are formed from these surfactants at the relatively low temperatures of the
wash liquor. The spreading of the undissolved surfactants over the
material to be cleaned and hence the promotion of the wash process do
not occur at these low temperatures. The Krafft point is the temperature at
which micelles are formed from the surtactants and the solubility of the
surfactant suddenly increases. C~6,~8 fatty alkyl sulfate typically has Krafft
points of 46 to 50°C. This means that these surfactants only dissolve
readily at temperatures above that range. Accordingly, these surfactants
which have excellent detersive properties are not really suitable for use
under modern washing conditions where washing is often carried out at
temperatures of up to 40°C.
Many proposals have been put fonrvard in the prior art with a view to
easing the problems discussed above. The use of structure breakers,
solubilizers, components for mixed micelle formation and the like has been
proposed in many different variants. One of these proposals provides for
the use of the particularly poorly soluble anionic surtactant salts based on
_ CA 02300786 2000-03-16
3
C,s,~B FAS (derived from corresponding saturated fatty alcohols) with
corresponding FAS components based on relatively short-chain fatty
alcohols containing in particular 10 to 14 carbon atoms. Overall distinctly
improved results are obtained, for example, when laundry detergents of the
type in question contain FAS-based anionic surfactants which contain at
least about 25 to 30% by weight (based on the FAS content) of these
comparatively short-chain FAS components. The adequate dissolution or
dispersion of the basically poorly soluble C~s,~B FAS components can be
ensured, even in the early stages of the wash process in domestic washing
machines. However, these comparatively short-chain fatty alcohol sulfates
make only a limited contribution to the cleaning result. DE 43 32 373 and
WO 94103077 describe corresponding water-free detergent mixtures based
on long-chain and relatively short-chain alkyl sulfates of the type in
question here and their use in detergents compacted by extrusion, fatty
alcohols and corresponding fatty alcohol ethoxylates containing 12 to 18
carbon atoms and up to an average of 5 EO groups in the structure breaker
molecule additionally being used as structure breakers.
According to German patent application DE 195 264 83, the
comparatively poorly soluble anionic surfactants based on relatively long
chain fatty alcohol sulfate salts surprisingly become readily soluble in the
water-based wash liquor, even at low temperatures of up to 40 or 50°C
and, more particularly, in the range from about 20 to 35°C, when they
are
used together with selected nonionic surfactant compounds from the class
of end-capped fatty alcohol oligoethoxylates andlor propoxylates in the
water-based wash liquor.
US 3,632,517 describes detergent compositions which, besides
FAS, also contain a-sulfofatty acid methyl ester (MES), soap flakes and
builders. This document makes use of the principle whereby mixtures of
surtactants can have a common Krafft point which is lower than the Krafft
point of any one of the surfactants. a.-Sulfofatty acid methyl ester in
CA 02300786 2000-03-16
4
particular is used to improve the solubility of alkyl(ene) sulfates. This
surfactant mixture has better detersive properties than FAS alone and
improves the dissolving behavior of FAS. Mixtures of FAS with MES and
soap flakes are particularly advantageous, especially in the presence of
disodium a-sulfofatty acids. The improvement in the dissolving properties
is reflected in a reduction of the Krafft point from 46°C in the case
of pure
FAS to 31-38°C in the mixture.
Although it is known from US 3,632,517 that mixtures of FAS with
MES and, in particular, soap can have lower Krafft points than pure FAS,
this document does not contain any reference to the fact that this principle
is also applicable to granules. In particular, apart from mentioning "mixing",
the document in question does not show how corresponding surfactant
mixtures are supposed to be incorporated in detergents.
It has been found that this principle is not applicable, particularly
when the surfactants are present in various granules or are unevenly
distributed in granules. If surfactant granules are to be used, particularly
in
modern high bulk density detergents, the problem posed by the poor
solubility of alkyl sulfates in cold water still exists. A way of providing
alkyl(ene) sulfates, more particularly long-chain alkyl sulfates, in granular
form which enables them to be used at low washing temperatures has now
been found.
It has been found that alkyl sulfate granules show an improved
detersive effect and, more particularly, improved solubility in cold water if
mixtures of the alkyl sulfates with certain other anionic surfactants are
present in the granules in such a form that, on dissolution, the granules
behave like granules of only one surfactant and, hence, also have only one
Krafft point.
In a first embodiment, therefore, the present invention relates to
anionic surfactant granules containing alkyl sulfate which are suitable as an
additive in detergents, characterized in that they contain at feast 45% by
CA 02300786 2000-03-16
weight of anionic surtactant, at least 20% by weight of the anionic
surfactant present consisting of alkyl sulfate, and in that the granules
contain at least two different anionic surfactants, but have only one Krafft
point which is below 46°C.
5 The Krafft point is determined by turbidity measurement in
accordance with DIN 53 918. The granules according to the invention have
advantages in particular in their solubility in cold water, i.e. in their
solubility
below 40°C. The improvement achieved is often considerably greater than
might have been assumed from the Krafft points considered in isolation.
In a second embodiment, therefore, the present invention relates to
anionic surfactant granules containing alkyl sulfate which are suitable as an
additive in detergents, characterized in that they contain at least 45% by
weight of anionic surfactant, at least 20% by weight of the anionic
surfactant present consisting of alkyl sulfate, in that the granules contain
at
least two different anionic surfactants and in that the granules leave behind
a residue of less than 5% by weight in the solubility test (L test at
30°C).
The solubility test (L test) is carried out as follows:
To determine solubility behavior (L test), 8 g of the granules to be
tested are scattered into a 2 liter glass beaker while stirring (800 r.p.m.,
laboratory stirrerlpropeller head centered 1.5 cm from the bottom of the
glass beaker) and stirred for 1.5 minutes at the measuring temperature
(30°C and 20°C). The test is carried out with water having a
hardness of
16°d. The liquor is then poured off through an 80 Nm sieve. The glass
beaker is rinsed out over the sieve with a very little cold water. A double
determination is carried out. The sieves are dried to constant weight at
40°C ~ 2°C in a drying cabinet and the residue is weighed out.
In this L test, the granules according to the invention leave behind
less than 5% by weight of residue at 30°C whereas pure alkyl sulfate
granules are poorly soluble and typically leave behind a residue of more
than 50% by weight under the conditions described here. Preferred
CA 02300786 2000-03-16
6
granules according to the invention leave behind a residue of less than 3%
by weight in the L test at 30°C, particularly advantageous embodiments
of
the invention leaving behind a residue of less than 5% by weight at
20°C.
The bulk density of the granules does not have to meet any
particular requirements. It is typically between 500 and 750 gll, depending
on the production process. If the granules have to satisfy particular bulk
density requirements for incorporation in detergents, the bulk density may
assume values above or below the above-mentioned range.
However, it is crucial that the surfactants are present in the form of a
homogeneous mixture in the granules. As far as is known at the present
time, it is only possible in this way to ensure that, on dissolution, the
granules behave like one surtactant and have only one Krafft point.
According to the invention, this Krafft point is lower than the Krafft point
of
the pure alkyl sulfate used in the granules. This homogeneous mixture is
obtained by using a homogeneous mixture of at least two of the surfactants
present, of which one is the alkyl sulfate, for the granulation step.
Alkyl sulfates in the context of the present invention are C8_22
alk(en)yl sulfates. The Cs_22 alkyl sulfates used are the alkali metal salts
and, in particular, the sodium salts of the sulfuric acid semiesters of Cs_z2
fatty alcohols, such as lauryl, myristyl, cetyl or stearyl alcohol, or of the
fatty alcohol mixtures obtained from coconut oil, palm and palm kernel oil,
which additionally contain unsaturated alcohols, for example oleyl alcohol,
or of C~o_2o oxoalcohols and the corresponding semiesters of secondary
alcohols with the same chain length. Other preferred alk(en)yl sulfates are
those with the chain length mentioned which contain a synthetic, linear
alkyl chain based on a petrochemical and which are similar in their
degradation behavior to the corresponding compounds based on oleo-
chemical raw materials. C,2_~s alkyl sulfates but especially Cps-~s alkyl
sulfates are preferred from the washing performance point of view.
_ CA 02300786 2000-03-16
_ 7
However, an alternative embodiment of the invention is charac-
terized by the use of unsaturated alkenyl sulfates with an alkenyl chain
length of preferably Cps to C2Z - which also come under the heading of alkyl
sulfates in the present specification - in addition to or instead of saturated
alkyl sulfates. In this embodiment, mixtures of saturated sulfonated fatty
alcohols consisting predominantly of Cps and unsaturated, sulfonated fatty
alcohols consisting predominantly of C~a, for example those derived from
solid or liquid fatty alcohol mixtures of the HD-Ocenol~ type (a product of
Henkel KGaA), are particularly preferred. Ratios by weight of alkyl sulfates
to alkenyl sulfates of 10:1 to 1:2 are preferred, ratios by weight of about
5:1
to 1:1 being particularly preferred. Other suitable alkyl sulfates are 2,3-
alkyl sulfates which may be produced, for example, in accordance with US
3,234,258 or US 5,075,041 and which are commercially obtainable as
products of the Shell Oil Company under the name of DAN~.
Besides the alkyl sulfates, the granules contain at least one other
anionic surfactant, the anionic surfactant selected here being one which is
capable of forming mixtures having only one Krafft point with alkyl sulfates,
the Krafft point of the mixture being lower than the Krafft point of the alkyl
sulfate used.
Surfactants of the sulfonate type are preferably used. Preferred
surfactants of the sulfonate type are Cs_~3 alkyl benzenesulfonates, olefin
sulfonates, i.e. mixtures of alkene and hydroxyalkane sulfonates, and the
disulfonates obtained, for example, from C~2_~8 monoolefins with an internal
or terminal double bond by sulfonation with gaseous sulfur trioxide and
subsequent alkaline or acidic hydrolysis of the sulfonation products. Other
suitable surfactants of the sulfonate type are alkane sulfonates obtained
from C~2_~8 alkanes, for example by sulfochlorination or sulfoxidation and
subsequent hydrolysis of neutralization. Also particularly suitable are the
esters of a-sulfofatty acids (ester sulfonates), for example the a-sulfonated
methyl esters (MES), more particularly the hydrogenated coconut, palm
CA 02300786 2000-03-16
8
kernel or tallow acids, which are obtained by a-sulfonation of the methyl
esters of fatty acids of vegetable andlor animal origin containing 8 to 20
carbon atoms in the fatty acid molecule and subsequent neutralization to
water-soluble monosalts. The esters in question are preferably the a-
sulfonated esters of hydrogenated coconut; palm, palm kernel or tallow
fatty acids. Sulfonation products of unsaturated fatty acids, for example
oleic acid, may also be present in small quantities, preferably in quantities
of not more than about 2 to 3% by weight. a-Sulfofatty acid alkyl esters
with an alkyl chain of not more than 4 carbon atoms in the ester group, for
example methyl esters, ethyl esters, propyl esters and butyl esters, are
particularly preferred. The methyl esters of a-sulfofatty acids (MES) are
used with particular advantage. According to the invention, it is
undesirable to use the so-called disalts of the a-sulfofatty acid methyl
esters, i.e. the dimetal-a-sulfofatty acids, because these compounds show
comparatively poor solubility and, accordingly, do not improve the solubility
of anionic surfactant granules are required in accordance with the
invention. Accordingly, dimetal-a-sulfofatty acids may only be present in
small quantities in the granules. In the context of the invention, a small
quantity of a-sulfofatty acid disalt is understood to mean that disalts of a-
sulfofatty acids make up less than 5% by weight of the granules and
preferably even less than 3% by weight of the granules. Granules which
contain a-sulfofatty acid methyl esters have a Krafft point below 46°C.
If
the granules contain alkyl benzenesulfonate in addition to alkyl sulfate, they
preferably have a Krafft point below 42°C.
Other suitable anionic surfactants are sulfonated fatty acid glycerol
esters which represent mono-, di- and triesters and mixtures thereof which
are obtained where production is carried out by esterification by a
monoglycerol containing 1 to 3 moles of fatty acid or in the transesterifica-
tion of triglycerides containing 0.3 to 2 moles glycerol. In addition, other
anionic surfactants, more particularly sulfuric acid monoesters of linear or
CA 02300786 2000-03-16
9
branched C~_2~ alcohols ethoxylated with 1 to 6 moles ethylene oxide, such
as 2-methyl-branched C9_» alcohols containing on average 3.5 moles
ethylene oxide (EO) or C~2_~8 fatty alcohols containing 1 to 4 EO, and the
salts of alkyl sulfosuccinic acid which are also known as sulfosuccinates or
as sulfosuccinic acid esters, may be used. Other suitable anionic
surfactants are fatty acid derivatives of amino acids, for example of N
methyl taurine (taurides) andlor of N-methyl glycine (sarcosides). The
sarcosides and sarcosinates, above all sarcosinates of higher and
optionally mono- or polyunsaturated fatty acids, such as oleyl sarcosinate,
are particularly preferred.
The anionic surfactants may be present in the form of their sodium,
potassium, ammonium or magnesium salts and as soluble salts of organic
bases, such as mono-, di- or triethanolamine. The anionic surfactants are
preferably present in the form of their sodium or potassium salts, more
particularly in the form of their sodium salts.
The granules contain anionic surfactants in quantities of at least
45% by weight, preferably in quantities of more than 50% by weight and
more preferably in quantities of more than 60% by weight. At least 20% by
weight of the anionic surfactant content must be made up by alkyl sulfates.
Alkyl sulfates are preferably present in the granules in quantities of 15 to
40% by weight, based on the granules. In another preferred embodiment,
the various anionic surfactants are present in similar quantities in the
granules. The preferred ratio of alkyl sulfate to a-sulfofatty acid methyl
ester is, for example, from 2:1 to 1:5 and more particularly from 1.5:1 to
1:3.
In terms of washing technology, particularly preferred granules
contain alkyl sulfate, a-sulfofatty acid methyl ester and alkyl benzenesul-
fonate each in quantities of 10 to 40% by weight and preferably 15 to 30%
by weight, both the ratio of alkyl sulfate to a-sulfofatty acid methyl ester
and
the ratio of alkyl sulfate to alkyl benzenesulfonate being in the range from
CA 02300786 2000-03-16
1.5:1 to 1:3. The Krafft point of such granules is distinctly reduced and is
below 42°C.
Besides the anionic surfactants, the granules may also contain
nonionic surfactants. Preferred nonionic surfactants are alkoxylated,
5 advantageously ethoxylated, more particularly primary alcohols preferably
containing 8 to 18 carbon atoms and an average of 1 to 12 moles ethylene
oxide (EO) per mole alcohol and alkyl glycosides corresponding the
general formula RO(G)x where R is a primary, linear or methyl-branched,
more particularly 2-methyl-branched, aliphatic radical containing 8 to 22
10 and preferably 12 to 18 carbon atoms and G stands for a glycose unit
containing 5 or 6 carbon atoms, preferably glucose. The degree of
oligomerization x, which indicates the distribution of monoglycosides and
oligoglycosides, is a number - which as an analytically determined quantity
may also be a broken number - between 1 and 10; x preferably has a value
below 2 and more preferably below 1.5. Other suitable surfactants are
polyhydroxyfatty acid amides corresponding to formula (I):
R2
R'-CO-N-[Z) (I)
in which RICO is an aliphatic acyl group containing 6 to 22 carbon atoms,
R2 is hydrogen, an alkyl or hydroxyalkyl group containing 1 to 4 carbon
atoms and [Z] is a linear or branched polyhydroxyalkyl group containing 3
to 10 carbon atoms and 3 to 10 hydroxyl groups. The polyhydroxyfatty acid
amides are preferably derived from reducing sugars containing 5 or 6
carbon atoms, more especially glucose. The group of polyhydroxyfatty
acid amides also includes compounds corresponding to formula (II):
R4-O-R5
R3-C 0-N-[Z) ( I I )
CA 02300786 2000-03-16
11
in which R3 is a linear or branched alkyl or alkenyl group containing 7 to 12
carbon atoms, R4 is a linear, branched or cyclic alkyl group or an aryl group
containing 2 to 8 carbon atoms and R5 is a linear, branched or cyclic alkyl
group or an aryl group or an oxyalkyl group containing 1 to 8 carbon atoms,
C~_4 alkyl or phenyl groups being preferred, and [Zj is a linear polyhydroxy-
alkyl group, of which the alkyl chain is substituted by at least two hydroxyl
groups, or alkoxylated, preferably ethoxylated or propoxylated, derivatives
of that group. Here, too, [Zj is preferably obtained by reductive amination
of a sugar, such as glucose, fructose, maltose, lactose, galactose,
mannose or xylose. The N-alkoxy- or N-aryloxy-substituted compounds
may then be converted into the required polyhydroxyfatty acid amides by
reaction with fatty acid methyl esters in the presence of an alkoxide as
catalyst, for example in accordance with the teaching of International
patent application WO 95!07331. If nonionic surfactants are present in the
granules, they are present in quantities of at most 20% by weight and
preferably at most 15% by weight.
The granules according to the invention preferably contain only
medium to small quantities of water because the flow behavior of the
surfactant granules deteriorates distinctly with increasing water content.
Accordingly, preferred granules according to the invention contain at most
10% by weight of water, preferably less than 7% by weight of water and,
above all where their surfactant content exceeds 70% by weight, preferably
less than 4.5% by weight of water.
The anionic surfactant granules preferably also contain carriers.
Particularly suitable carriers are compounds which are capable of
performing a builder or co-builder function in detergents. The compounds
in question may be inorganic or organic compounds.
Suitable inorganic carrier components are, in particular, alumosili
cates, alkali metal sulfates and alkali metal carbonates. In another pre
ferred embodiment of the invention, various inorganic carriers are used in
CA 02300786 2000-03-16
12
combination with one another. In particular, a combination of alumosilicate
and soda in which the ratio by weight of alumosilicate to soda is from 1:5 to
5:1 and more particularly from 1:2 to 2:1 has proved to be an advanta-
geous carrier in anionic surfactant granules.
Among the alumosilicates, crystalline alumosilicates, i.e. zeolites,
are preferably used. Preferred zeolite carriers are the zeolites A, P, X and
Y and mixtures thereof. The use of zeolite A as a carrier is known from
numerous publications. However, zeolite P and faujasite zeolites have a
higher oil absorption capacity than zeolite A and, accordingly, may be
preferred in granules. In one advantageous embodiment of the invention,
therefore, at least part of the zeolite used, preferably at least 20% by
weight, and preferably the entire zeolite consists of faujasite zeolite. In
the
context of the present invention, the expression "faujasite zeolite"
characterizes all three zeolites which form the faujasite subgroup of zeolite
structure group 4. According to the invention, therefore, zeolite Y and
faujasite and mixtures of these compounds may be used in addition to
zeolite X, although pure zeolite X is preferred. For example, the zeolite A-
LSX described in European patent application EP-A-816 291, which
corresponds to a co-crystallizate of zeolite X and zeolite A and which in its
water-free form has the formula (Mv"O + M'2,"O) ~ AI203 ~ zSi02 where M
and M' may be alkali or alkaline earth metals and z is a number of 2.1 to
2.6, may also be used with advantage in the process according to the
invention. This product is commercially obtainable under the name of
VEGOBOND AX from CONDEA Augusta S.p.A. If zeolite P is used, it may
be of advantage to use the zeolite MAP described in European patent EP-
B-380 070. The particle sizes of the zeolites used in accordance with the
invention is preferably in the range from 0.1 to 100 Nm, more preferably in
the range from 0.5 to 50 Nm and most preferably in the range from 1 to 30
Nm, as measured by standard particle size determination methods.
Organic builder components suitable as carriers are, in particular,
CA 02300786 2000-03-16
13
polycarboxylates, for example the polycarboxylic acids usable in the form of
their sodium salts (polycarboxylic acids in this context being understood to
be carboxylic acids carrying more than one acid function). Examples of
such polycarboxylic acids include citric acid, adipic acid, succinic acid,
glutaric acid, malic acid, tartaric acid, malefic acid, fumaric acid, sugar
acids, aminocarboxylic acids, nitrilotriacetic acid (NTA), providing its use
is
not ecologically unsafe, and mixtures thereof. 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, more
particularly trisodium citrate.
Polymeric polycarboxylates are also suitable organic carrier
materials. These are, for example, the alkali metal salts of polyacrylic acid
or polymethacrylic acid, for example those with a relative molecular weight
of 500 to 70,000 glmole. The molecular weights mentioned in this
specification for polymeric polycarboxylates are weight-average molecular
weights MW of the particular acid form which, basically, were determined by
gel permeation chromatography (GPC) using a UV detector. The
measurement was carried out against an external polyacrylic acid standard
which provides realistic molecular weight values by virtue of its structural
similarity to the polymers investigated. These values differ distinctly from
the molecular weights measured against polystyrene sulfonic acids as
standard. The molecular weights measured against polystyrene sulfonic
acids are generally far higher than the molecular weights mentioned in this
specification. Suitable polymers are, in particular, polyacrylates which
preferably have a molecular weight of 2,000 to 20,000 glmole. By virtue of
their superior solubility, preferred representatives of this group are the
short-chain polyacrylates which have molecular weights of 2,000 to 10,000
glmole and, more particularly, 3,000 to 5,000 glmole. Also suitable are
copolymeric polycarboxylates, particularly those of acrylic acid with
methacrylic acid and those of acrylic acid or methacrylic acid with malefic
- CA 02300786 2000-03-16
14
acid. Acrylic acidlmaleic acid copolymers containing 50 to 90% by weight
of acrylic acid and 50 to 10% by weight of malefic acid have proved to be
particularly suitable. Their relative molecular weights, based on the free
acids, are generally in the range from 2,000 to 70,000 glmole, preferably in
the range from 20,000 to 50,000 glmole and more preferably in the range
from 30,000 to 40,000 glmole.
In particularly advantageous embodiments, mixtures of organic and
inorganic carriers may also be used. Irrespective of whether mixtures of
different carriers or only one carrier component islare used, the carrier
content of the granules is preferably between 5 and 55% by weight.
However, from the point of view of providing concentrated anionic surfac-
tant granules, the carrier content of the granules is preferably below 50%
by weight and more preferably below 40% by weight, carbonates in
particular preferably being present in quantities of less than 30% by weight.
If the granules are intended to have low water contents, it is
particularly preferred to use as carriers compounds which are capable of
absorbing moisture in the granules and which therefore prevent the anionic
surfactants from becoming tacky. The use of carriers such as these thus
improves the flow behavior and dissolving behavior of such granules and
increases their stability in storage. Carriers particularly suitable for this
purpose are the faujasite zeolites and zeolite P and, in addition, calcined
soda for example. To increase the stability of the granules according to the
invention in storage, it is preferred to use the zeolite in an overdried form,
i.e. in a form in which it has a water content removable at 800°C which
is
lower than the equilibrium water content of the zeolite used.
Basically, any granulation process may be used to produce the
granules according to the invention which have only one Krafft point and
which are readily soluble. It has proved to be crucially important to use
thoroughly mixed surfactant pastes with a substantially neutral pH for the
granulation step.
CA 02300786 2000-03-16
Accordingly, preferred granules are obtained by preparing and
thoroughly mixing a paste of at least two anionic surfactants, adjusting this
paste to a pH of 6.0 to 8.5 and then subjecting the paste to a granulation
step.
5 The present invention also relates to a process for the production of
anionic surfactant granules with a Krafft point below 46°C which are
suitable as an additive in detergents, characterized in that a paste of at
least two anionic surfactants is prepared and thoroughly mixed,
subsequently adjusted to a pH of 6.0 to 8.5 and then subjected to a
10 granulation step.
Suitable surfactants are the surfactants described in the foregoing,
the anionic surfactants being used in the form of pastes, preferably water-
containing pastes. In one particularly preferred embodiment, one of the
anionic surfactants is an alkyl sulfate. However, this production process
15 may also be used with advantage for the production of anionic surfactant
granules free from alkyl sulfate.
The pastes may be mixed in any liquid mixer which provides for
thorough mixing. Suitable mixers include, for example, static mixers
(manufacturer: Sulzer or Kenics), loop reactors and mixing vessels with an
intensive stirrer. The only important requirement is that the anionic
surfactants should be present in the resulting paste in the form of a
homogeneous mixture.
The pH is preferably adjusted using an acidic component. Any
acidic components suitable for use in detergents may advantageously be
used for this purpose. These include both carboxylic acids and mineral
acids or acidic salts of mineral acids. Among the carboxylic acids, those
which are also suitable as co-builders are particularly preferred.
Corresponding carboxylic acids are, in particular, polycarboxylic acids,
such as citric acid, adipic acid, succinic acid, glutaric acid, tartaric acid,
sugar acids, aminocarboxylic acids, nitrilotriacetic acid (NTA), providing its
CA 02300786 2000-03-16
16
use is not ecologically unsafe, and mixtures thereof. These acids may be
used in water-free form or in the form of their hydrates. Among the mineral
acids which may be used, sulfuric acid, phosphoric acid, carbonic acid and
hydrochloric acid and acidic salts thereof are particularly suitable.
According to the invention, citric acid and/or sodium hydrogen sulfate is
preferably used as the acidic component, the use of citric acid on its own
representing a particularly advantageous embodiment. The pH is
preferably adjusted to a value in the neutral range (6.0 to 8.5), pH values of
6.5 to 8.0 being preferred.
The pH adjustment step crucial to the invention leads to various
advantages. On the one hand, the viscosity of neutral anionic surfactant
pastes is generally lower than the viscosity of alkaline anionic surfactant
pastes. Accordingly, the pastes are easier to process and, in particular,
can be economically sprayed through the pH adjustment. On the other
hand, it can be of advantage to the use of the resulting granules if they
have a neutral effect. This is the case in particular where the granules are
used in compositions which can come into contact with the human skin in
use. Thus, it can be advisable to use neutral components, for example, in
cosmetic products and in detergents, for example hand washing
detergents.
In cases where a-sulfofatty acid methyl esters in particular are used
as the anionic surtactant, adjustment of the pH value performs another
crucial function, i.e. it suppresses the hydrolysis of the methyl ester which
occurs in the alkaline pH range, particularly at elevated temperature, and
which leads to the unwanted formation of the so-called disalt, more
particularly the disodium salt, of the corresponding sulfofatty acid.
Accordingly, the process described herein is particularly suitable for the
production of anionic surfactant granules which contain a-sulfofatty acid
methyl ester but only a small amount of a-sulfofatty acid disodium salt. A
small amount of a-sulfofatty acid disodium salt in the context of the
CA 02300786 2000-03-16
17
invention is understood to mean that disalts of a-sulfofatty acids make up
less than 5% by weight and preferably less than 3% by weight of the
granules.
The subsequent granulation step may be carried out in any suitable
granulator. However, the paste is preferably granulated by spray
agglomeration, preferably using a carrier component, and is preferably
dried at the same time.
The granulation step may be carried out in any mixerlgranulator
suitable for spray agglomeration. However, the granulation step is
preferably carried out in a batch-type or continuous fluidized bed. In one
particularly preferred embodiment, the process is carried out continuously
in a fluidized bed. In this case, the liquid preparations are introduced into
the fluidized bed through one-component or multicomponent nozzles or
through several nozzles.
The production of the granules may be carried out as described in
European patent EP-B-603 207. According to the teaching of this patent, a
surfactant preparation which contains a non-surfactant liquid component
and which is present in liquid to paste-like form under normal pressure at
to 40°C, is granulated and at the same time dried. Advantages of this
20 process for the production of free-flowing granules of various types of
surfactant include the avoidance of brown discoloration of the surfactants
through gentle drying and the absence of any dust in the granules.
The carrier materials used are the carriers described in the
foregoing. The carrier component and any other solids present are
introduced either pneumatically as powders through blow pipes, in which
case they are added before or during spraying of the liquid components, or
as a solution or suspension in admixture with the liquids. The liquid
constituents are mixed either before spraying or in the nozzle itself. The
nozzle or nozzles may be arranged in any way and may be angled to spray
CA 02300786 2000-03-16
18
in any direction providing a substantially uniform distribution of the liquid
components in the fluidized bed is achieved.
Preferred fluidized bed granulators have base plates with dimen
sions of at least 0.4 m. Fluidized beds with a base plate between 0.4 and 5
m in diameter, for example 1.2 m or 2.5 m in diameter, are particularly
preferred. However, fluidized beds with a base plate larger than 5 mm in
diameter are also suitable. A perforated base plate or a so-called Conidur
plate (manufacturer: Hein & Lehmann, Federal Republic of Germany) is
preferably used as the base plate. The process according to the invention
is preferably carried out at fluidizing air flow rates of 1 to 8 mls and
preferably 1.5 to 5.5 mls.
The granules are advantageously discharged from the fluidized bed
via a grading stage. Grading may be carried out, for example, with a sieve
or by a stream of drying air (grading air) flowing in countercurrent which is
controlled in such a way that only particles beyond a certain particle size
are removed from the fluidized bed while smaller particles are retained
therein. In one preferred embodiment, the inflowing air is made up of the
heated or unheated grading air and the heated bottom air. The bottom air
temperature is preferably between 80 and 400°C and more preferably
between 90 and 350°C. The fluidizing air cools through heat losses and
through the heat of evaporation of the constituents of the solvent. In one
particularly preferred embodiment, the temperature of the fluidizing air
about 5 cm above the base plate is in the range from 60 to 120°C and
preferably in the range from 70 to 100°C. The air exit temperature is
between 60 and 120°C and more particularly below 100°C.
If the granules are discharged from the fluidized bed against a
stream of grading air, as described in EP-B-0 603 207, the granules
obtained as a result of this grading are free from dust, i.e. are above 0.2
mm in size. According to the invention, preferred granules have a dso value
of 0.4 to 2.0 mm. In one particularly preferred embodiment, particles larger
CA 02300786 2000-03-16
19
than 2.0 mm in size are returned. This coarse-particle fraction may either
be added to the fluidized bed as a solid component after grinding or is
redissolved and sprayed into the fluidized bed.
In addition, the fluidized bed granulator may be an apparatus for
producing a rotation of air about the vertical axis of a fluidized bed, as
described for example in earlier German patent application DE 198 50
099.8, which is designed in such a way that an air inlet is located above the
horizontal diffusor plate which has at least two injection tubes arranged at
uniform intervals apart from one another and at the same height above the
diffusor plate at an angle of inclination of at least 30° and at most
90°.
Through a circular fluidized bed with an ascending outer flow, this
apparatus leads to a uniform distribution of temperature. In addition, in an
apparatus such as this, it is possible to produce particularly spherical
granules because the vertical flow in the outer regions of the fluidized bed
has a higher flow rate than at the center of the fluidized bed and produces
a turbulent flow about the vertical axis of the fluidized bed through the
introduction of air above the diffusor plate.
In the granulation step according to the invention, a so-called
powdering agent may be continuously introduced into the fluidized bed to
maintain the fluidized-bed granulation process. Zeolites are preferably
used as the powdering material, the zeolites used in accordance with the
invention as carriers being particularly preferred powdering materials.
These powdering materials additionally prevent the moist granules from
becoming tacky during the granulation step and thus promote fluidization
and drying to form the desired product. The particle size of the powdering
material is below 100 Nm so that the granules obtained contain between 1
and 4% by weight of the powdering material. Although this variant can be
of advantage for the production of granules by the process according to the
invention, it is by no means absolutely essential.
CA 02300786 2000-03-16
The present invention also relates to detergents which, besides
other constituents, contain anionic surtactant granules according to the
invention of at least one type or anionic surfactant granules produced by
the process according to the invention.
5 The detergents according to the invention, which may be present as
granules, powder-form or tablet-form solids or other shaped bodies, may in
principle contain any known ingredients typical of detergents in addition to
the compounds mentioned. The detergents are produced by methods
known per se. To this end, the anionic surfactant granules according to the
10 invention are mixed with other particulate ingredients. The mixtures
obtained may be subjected to further compounding steps including, in
particular, compaction of the ingredients which is preferably carried out by
a press agglomeration process. The press agglomeration process to which
the solid premix is subjected may be carried out in various agglomerators.
15 Press agglomeration processes are classified according to the type or
agglomerator used. The four most common press agglomeration
processes preferably used in accordance with the invention are extrusion,
roll pressing or compacting, pelleting and tabletting, so that preferred press
agglomeration processes in the context of the invention are extrusion, roll
20 compacting, pelleting and tabletting processes.
Ingredients of the detergents according to the invention are, first and
foremost, anionic, nonionic, cationic, amphoteric and/or zwitterionic surfac-
tants.
Suitable anionic surfactants are in particular the surtactants already
mentioned in the foregoing which are preferably used in the form of the
granules according to the invention. Other suitable anionic surfactants are,
in particular, soaps, for example in quantities of 0.2 to 5% by weight.
Suitable soaps are, 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 soap mixtures derived in particular from
CA 02300786 2000-03-16
21
natural fatty acids, for example coconut, palm kernel or tallow fatty acids.
The anionic surfactants, including the soaps, may be present in the
form of their sodium, potassium or ammonium salts and as soluble salts of
organic bases, such as mono-, di- or triethanolamine. The anionic
surfactants are preferably present in the form of their sodium or potassium
salts and, more preferably, in the form of their sodium salts. Anionic
surtactants are present in the detergents according to the invention in
quantities of preferably 1 % by weight to 35% by weight and more
preferably in quantities of 5% by weight to 30% by weight.
Preferred nonionic surfactants are - again - the surtactants
mentioned in the foregoing. More particularly, these nonionic surtactants
are alkoxylated, advantageously ethoxylated, more especially primary
alcohols preferably containing 8 to 18 carbon atoms and, on average, 1 to
12 moles of ethylene oxide (EO) per mole of alcohol, in which the alcohol
radical may be linear or, preferably, methyl-branched in the 2-position or
may contain linear and methyl-branched radicals in the form of the mixtures
typically present in oxoalcohol radicals. However, alcohol ethoxylates
containing linear radicals of alcohols of native origin with 12 to 18 carbon
atoms, for example coconut, palm, tallow or oleyl alcohol, and on average 2
to 8 EO per mole of alcohol are particularly preferred. Preferred
ethoxylated alcohols include, for example, C,2_,4 alcohols containing 3 EO
or 4 E0, Cs_,~ alcohols containing 7 E0, C~3_~s alcohols containing 3 EO, 5
EO, 7 EO or 8 EO, C~2_~8 alcohols containing 3 EO, 5 EO or 7 EO and
mixtures thereof, such as mixtures of C~2_~4 alcohol containing 3 EO and
C~2_~8 alcohol containing 7 EO. The degrees of ethoxylation mentioned
represent statistical mean values which, for a special product, can be a
whole number or a broken number. Preferred alcohol ethoxylates have a
narrow homolog distribution (narrow range ethoxylates, NRE). In addition
to these nonionic surfactants, fatty alcohols containing more than 12 EO
may also be used, examples including (tallow) fatty alcohols containing 14
CA 02300786 2000-03-16
22
E0, 16 E0, 20 E0, 25 E0, 30 EO or 40 EO.
The nonionic surfactants also include alkyl glycosides corresponding
the general formula RO(G)x where R is a primary, linear or methyl-
branched, more particularly 2-methyl-branched, aliphatic radical containing
8 to 22 and preferably 12 to 18 carbon atoms and G stands for a glycose
unit containing 5 or 6 carbon atoms, preferably glucose. The degree of
oligomerization x, which indicates the distribution of monoglycosides and
oligoglycosides, is a number - which as an analytically determined quantity
may also be a broken number - between 1 and 10 and preferably between
1.2 and 4.
Other suitable nonionic surfactants are polyhydroxyfatty acid amides
corresponding to formula (I):
R2
R'-CO-N-[Z] ( I)
in which R'CO is an aliphatic acyl group containing 6 to 22 carbon atoms,
R2 is hydrogen, an alkyl or hydroxyalkyl group containing 1 to 4 carbon
atoms and [Z] is a linear or branched polyhydroxyalkyl group containing 3
to 10 carbon atoms and 3 to 10 hydroxyl groups. The polyhydroxyfatty acid
amides are preferably derived from reducing sugars containing 5 or 6
carbon atoms, more especially glucose. The group of polyhydroxyfatty
acid amides also includes compounds corresponding to formula (II):
Ra-0-Rs
R3-C O-N-[Z] ( I I )
in which R3 is a linear or branched alkyl or alkenyl group containing 7 to 12
carbon atoms, R4 is a linear, branched or cyclic alkylene group or an
arylene group containing 2 to 8 carbon atoms and Rs is a linear, branched
or cyclic alkyl group or an aryl group or an oxyalkyl group containing 1 to 8
CA 02300786 2000-03-16
23
carbon atoms, C~_4 alkyl or phenyl groups being preferred, and [Z) is a
linear polyhydroxyalkyl group, of which the alkyl chain is substituted by at
least two hydroxyl groups, or alkoxylated, preferably ethoxylated or
propoxylated, derivatives of that group. Here, too, [Z] is preferably
obtained by reductive amination of a sugar, such as glucose, fructose,
maltose, lactose, galactose, mannose or xylose. The N-alkoxy- or N-
aryloxy-substituted compounds may then be converted into the required
polyhydroxyfatty acid amides by reaction with fatty acid methyl esters in the
presence of an alkoxide as catalyst, for example in accordance with the
teaching of International patent application WO 95107331.
Another class of preferred nonionic surfactants which may be used
either as sole nonionic surfactant or in combination with other nonionic
surfactants, more particularly together with alkoxylated fatty alcohols andlor
alkyl glycosides, are alkoxylated, preferably ethoxylated or ethoxylated and
propoxylated, fatty acid alkyl esters preferably containing 1 to 4 carbon
atoms in the alkyl chain, more especially the fatty acid methyl esters which
are described, for example, in Japanese patent application JP 581217598
or which are preferably produced by the process described in International
patent application WO 90113533.
Nonionic surfactants of the amine oxide type, for example N-coconut
alkyl-N,N-dimethylamine oxide and N-tallow alkyl-N,N-dihydroxyethylamine
oxide, and the fatty acid alkanolamide type are also suitable. The quantity
in which these nonionic surfactants are used is preferably no more than the
quantity in which the ethoxylated fatty alcohols are used and, more
preferably, no more than half that quantity.
Other suitable surfactants are so-called gemini surtactants. Gemini
surfactants are generally understood to be compounds which contain two
hydrophilic groups per molecule. These groups are generally separated
from one another by a so-called "spacer". The spacer is generally a
carbon chain which should be long enough for the hydrophilic groups to
CA 02300786 2000-03-16
24
have a sufficient spacing to be able to act independently of one another.
Gemini surfactants are generally distinguished by an unusually low critical
micelle concentration and by an ability to reduce the surface tension of
water to a considerable extent. In exceptional cases, however, gemini
surfactants are not only understood to be dimeric surfactants, but also
trimeric surtactants. Suitable gemini surfactants are, for example, the
sulfated hydroxy mixed ethers according to German patent application DE
43 21 022 and the dimer alcohol bis- and trimer alcohol tris-sulfates and -
ether sulfates according to German patent application 195 03 061. The
end-capped dimeric and trimeric mixed ethers according to earlier German
patent application 195 13 291.9 are distinguished in particular by their
bifunctionality and multifunctionality. Thus, the end-capped surtactants
mentioned exhibit good wetting properties and are low-foaming so that they
are particularly suitable for use in machine washing or cleaning processes.
However, the gemini polyhydroxyfatty amides or poly-polyhydroxyfatty acid
amides described in International patent applications WO 95/19953, WO
95119954 and WO 95119955 may also be used.
The detergents according to the invention also contain a builder
system consisting of organic andlor inorganic builders.
Useful organic builders are, for example, the polycarboxylic acids
usable, for example, in the form of their sodium salts (polycarboxylic acids
in this context being understood to be carboxylic acids carrying more than
one acid function). Examples include citric acid, adipic acid, succinic acid,
glutaric acid, malic acid, tartaric acid, malefic acid, fumaric acid, sugar
acids, aminocarboxylic acids, nitrilotriacetic acid (NTA), providing its use
is
not ecologically unsafe, and mixtures thereof. 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. The acids per
se may also be used. Besides their builder effect, the acids typically have
the property of an acidifying component and hence, as in the granules
CA 02300786 2000-03-16
according to the invention for example, are also used to establish a lower
and more mild pH value in laundry or dishwashing detergents. Citric acid,
succinic acid, glutaric acid, adipic acid, gluconic acid and mixtures thereof
are particularly mentioned in this regard.
5 Other suitable builders are polymeric polycarboxylates such as, for
example, the alkali metal salts of polyacrylic acid or polymethacrylic acid,
for example those having a relative molecular weight of 500 to 70,000
glmole. This class of substances is described in detail in the foregoing.
The (co)polymeric polycarboxylates may be used either in powder form or
10 in the form of an aqueous solution. The content of (co)polymeric
polycarboxylates in the compositions is preferably between 0.5 and 20% by
weight and more preferably between 3 and 10% by weight.
In order to improve their solubility in water, the polymers may also
contain allyl sulfonic acids, for example allyloxybenzenesulfonic acid and
15 methallyl sulfonic acid (cf. EP-B-727 448), as monomer. Biodegradable
polymers of more than two different monomer units are also particularly
preferred, examples including those which contain salts of acrylic acid and
malefic acid and vinyl alcohol or vinyl alcohol derivatives as monomers
according to DE-A-43 00 772 or those which contain salts of acrylic acid
20 and 2-alkylallyl sulfonic acid and sugar derivatives as monomers according
to DE-C-42 21 381. Other preferred copolymers are those described in
German patent applications DE-A-43 03 320 and DE-A-44 17 734 which
preferably contain acrolein and acrylic acid/acrylic acid salts or acrolein
and
vinyl acetate as monomers. Other preferred builders are polymeric
aminodicarboxylic acids, salts or precursors thereof. Polyaspartic acids or
salts and derivatives thereof which, according to German patent application
DE-A-195 40 086, have a bleach-stabilizing effect in addition to their co-
builder properties are particularly preferred.
Other suitable builders are polyacetals which may be obtained by
reaction of dialdehydes with polyol carboxylic acids containing 5 to 7
CA 02300786 2000-03-16
26
carbon atoms and at least three hydroxyl group, for example as described
in European patent application EP-A-0 280 223. Preferred polyacetals are
obtained from dialdehydes, such as glyoxal, glutaraldehyde, terephthal-
aldehyde and mixtures thereof and from polyol carboxylic acids, such as
gluconic acid andlor glucoheptonic acid.
Other suitable organic builders are dextrins, for example oligomers
or polymers of carbohydrates which may be obtained by partial hydrolysis
of starches. The hydrolysis may be carried out by standard methods, for
example acid- or enzyme-catalyzed methods. The end products are
preferably hydrolysis products with average molecular weights of 400 to
500,000 glmole. A polysaccharide with a dextrose equivalent (DE) of 0.5 to
40 and, more particularly, 2 to 30 is preferred, the DE being an accepted
measure of the reducing effect of a polysaccharide by comparison with
dextrose which has a DE of 100. Both maltodextrins with a DE of 3 to 20
and dry glucose syrups with a DE of 20 to 37 and also so-called yellow
dextrins and white dextrins with relatively high molecular weights of 2,000
to 30,000 glmole may be used. A preferred dextrin is described in British
patent application 94 19 091. The oxidized derivatives of such dextrins are
their reaction products with oxidizing agents which are capable of oxidizing
at least one alcohol function of the saccharide ring to the carboxylic acid
function. Dextrins thus oxidized and processes for their production 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 92118542, WO 93108251, WO
93116110, WO 95107303, WO 95/12619 and WO 95120608. An oxidized
oligosaccharide according to German patent application DE-A-196 00 018
is also suitable. A product oxidized at C6 of the saccharide ring can be
particularly advantageous.
Other suitable co-builders are oxydisuccinates and other derivatives
of disuccinates, preferably ethylenediamine disuccinate. Ethylenedia~mine-
CA 02300786 2000-03-16
27
N,N'-disuccinate (EDDS), of which the synthesis is described for example
in US 3 158 615, is preferably used in the form of its sodium or magnesium
salts. The glycerol disuccinates and glycerol trisuccinates described, for
example, in US 4,524,009, in US 4,639,325, in European patent application
EP-A-0 150 930 and in Japanese patent application JP 931339896 are also
particularly preferred in this connection. The quantities used in zeolite-
containing andlor silicate-containing formulations are from 3 to 15% by
weight.
Other useful organic co-builders are, for example, acetylated
hydroxycarboxylic acids and salts thereof which may optionally be present
in lactone form and which contain at least 4 carbon atoms, at least one
hydroxy group and at most two acid groups. Co-builders such as these are
described, for example, in International patent application WO 95120029.
Another class of substances with co-builder properties are the
phosphonates, more particularly hydroxyalkane and aminoalkane phos
phonates. Among the hydroxyalkane phosphonates, 1-hydroxyethane-1,1
diphosphonate (HEDP) is particularly important as a co-builder. It is
preferably used in the form of a sodium salt, the disodium salt showing a
neutral reaction and the tetrasodium salt an alkaline ration (pH 9).
Preferred aminoalkane phosphonates are ethylenediamine tetramethylene
phosphonate (EDTMP), diethylenetriamine pentamethylene phosphonate
(DTPMP) and higher homologs thereof. They are preferably used in the
form of the neutrally reacting sodium salts, for example as the hexasodium
salt of EDTMP and as the hepta- and octasodium salt of DTPMP. Within
the class of phosphonates, HEDP is preferably used as builder. The
aminoalkane phosphonates also show a pronounced heavy metal binding
capacity. Accordingly, it can be of advantage, particularly where the
detergents also contain bleaching agents, to use aminoalkane
phosphonates, more especially DTPMP, or mixtures of the phosphonates
mentioned.
CA 02300786 2000-03-16
- 28
In addition, any compounds capable of forming complexes with
alkaline earth metal ions may be used as co-builders.
An inorganic builder preferably used is the finely crystalline synthetic
zeolite containing bound water already described as a carrier for the
granules according to the invention.
Suitable partial substitutes for zeolites are layer silicates of natural
and synthetic origin. Such layer silicates are known, for example, from
patent applications DE-B-23 34 899, EP-A- 0 026 529 and DE-A-35 26
405. Their suitability is not confined to a particular composition or
structural
formula. However, smectites, especially bentonites, are preferred. Other
suitable substitutes for zeolites or phosphates are crystalline layer-form
sodium silicates corresponding to the general formula NaMSixOzx+~DyH20,
where M is sodium or hydrogen, x is a number of 1.9 to 4 and y is a
number of 0 to 20, preferred values for x being 2, 3 or 4. Crystalline layer
silicates such as these are described, for example, in European patent
application EP-A-0 164 514. Preferred crystalline layer silicates
corresponding to the above formula are those in which M is sodium and x
assumes the value 2 or 3. Both Vii- and 8-sodium disilicates -
Na2Si20s~yH20 are particularly preferred.
Other preferred builders are amorphous sodium silicates with a
modulus (Na20:Si02 ratio) of 1:2 to 1:3.3, preferably 1:2 to 1:2.8 and more
preferably 1:2 to 1:2.6 which dissolve with delay and exhibit multiple wash
cycle properties. The delay in dissolution in relation to conventional
amorphous sodium silicates can have been obtained in various ways, for
example by surface treatment, compounding, compacting or by overdrying.
In the context of the invention, the term "amorphous" is also understood to
encompass "X-ray amorphous". In other words, the silicates do not
produce any of the sharp X-ray reflexes typical of crystalline substances in
X-ray diffraction experiments, but at best one or more maxima of the
scattered X-radiation which have a width of several degrees of the
CA 02300786 2000-03-16
29
diffraction angle. Particularly good builder properties may even be
achieved where the silicate particles produce crooked or even sharp
diffraction maxima in electron diffraction experiments. This may be
interpreted to mean that the products have microcrystalline regions
between 10 and a few hundred nm in size, values of up to at most 50 nm
and, more particularly, up to at most 20 nm being preferred. So-called X-
ray amorphous silicates such as these, which also dissolve with delay in
relation to conventional waterglasses, are described for example in
German patent application DE-A-44 00 024. Compacted amorphous sili-
Gates, compounded amorphous silicates and overdried X-ray-amorphous
silicates are particularly preferred, the overdried silicates also preferably
occurring as carriers in the granules according to the invention or being
used as carriers in the process according to the invention.
The generally known phosphates may of course also be used as
builders providing their use is not ecologically problematical. The sodium
salts of orthophosphates, pyrophosphates and, in particular, tripoly
phosphates are particularly suitable. Their content is generally no more
than 25% by weight and preferably no more than 20% by weight, based on
the final detergent. In some cases, it has been found that tri
polyphosphates in particular, even in small quantities of up to at most 10%
by weight, based on the final detergent, produce a synergistic improve-
ment in multiple wash cycle performance in combination with other
builders.
Among the compounds yielding H202 in water which serve as
bleaching agents, sodium perborate mono- and tetrahydrate and sodium
percarbonate are particularly important. Other useful bleaching agents are,
for example, peroxypyrophosphates, citrate perhydrates and H202-yielding
peracidic salts or peracids, such as perbenzoates, peroxophthalates,
diperazelaic acid, phthaloiminoperacid or diperdodecane dioic acid. The
content of bleaching agents in the detergents according to the invention is
CA 02300786 2000-03-16
- 30
between 0 and 30% by weight and more preferably between 5 and 25% by
weight, perborate monohydrate or percarbonate advantageously being
used.
In order to obtain an improved bleaching effect where washing is
carried out at temperatures of 60°C or lower, bleach activators may be
incorporated in the preparations. Examples of bleach activators are N-acyl
or O-acyl compounds which form organic peracids with H202, preferably
polyacylated alkylene diamines, such as N,N'-tetraacylated diamines,
acylated glycolurils, more especially tetraacetyl glycoluril, N-acylated
hydantoins, hydrazides, triazoles, triazines, urazoles, diketopiperazines,
sulfuryl amides and cyanurates, also carboxylic acid esters, such as p-
(alkanoyloxy)-benzenesulfonates, more especially sodium isononanoyloxy-
benzenesulfonate, and p-(alkenoyloxy)-benzenesulfonates; caprolactam
derivatives, carboxylic anhydrides, such as phthalic anhydride, and esters
of polyols, such as glucose pentaacetate. Other known bleach activators
are the acetylated mixtures of sorbitol and mannitol described, for example,
in European patent application EP-A-0 525 239 and acetylated
pentaerythritol. The content of bleach activators in the bleach-containing
detergent is in the usual range, preferably between 1 and 10% by weight
and more preferably between 3 and 8% by weight. Particularly preferred
bleach activators are N,N,N',N'-tetraacetyl ethylenediamine (TAED), 1,5-
diacetyl-2,4-dioxohexahydro-1,3,5-triazine (DADHT) and acetylated
sorbitol-mannitol mixtures (SORMAN). The bleach activator can have been
coated in known manner with shell-forming materials or granulated or
extrudedlpelleted, optionally using auxiliaries, especially methyl celluloses
andlor carboxymethyl celluloses, and - if desired - may contain other
additives, for example dye. Granules such as these preferably contain
more than 70% by weight and, more preferably, from 90 to 99% by weight
of bleach activator. A bleach activator which forms peracetic acid under
washing conditions is preferably used.
CA 02300786 2000-03-16
- 31
In addition to or instead of the conventional bleach activators
mentioned above, the sulfonimines known from European patents EP 0
446 982 and EP 0 453 003 andlor bleach-boosting transition metal salts or
transition metal complexes may also be present as so-called bleach
catalysts. Suitable transition metal compounds include, in particular, the
manganese-, iron-, cobalt-, ruthenium- or molybdenum-salen complexes
known from German patent application DE 195 29 905 and the N-analog
compounds thereof known from German patent application DE 196 20 267,
the manganese-, iron-, cobalt-, ruthenium- or molybdenum-carbonyl
complexes known from German patent application DE 195 36 082, the
manganese, iron, cobalt, ruthenium, molybdenum, titanium, vanadium and
copper complexes with nitrogen-containing tripod ligands described in
German patent application DE 196 05 688, the cobalt-, iron-, copper- and
ruthenium-amine complexes known from German patent application DE
196 20 411, the manganese, copper and cobalt complexes described in
German patent application DE 44 16 438, the cobalt complexes described
in European patent application EP 0 272 030, the manganese complexes
known from European patent application EP 0 693 550, the manganese,
iron, cobalt and copper complexes known from European patent EP 0 392
592 andlor the manganese complexes described in European patent EP 0
443 651 or in European patent applications EP 0 458 397, EP 0 458 398,
EP 0 549 271, EP 0 549 272, EP 0 544 490 and EP 0 544 519.
Combinations of bleach activators and transition metal bleach catalysts are
known, for example, from German patent application DE 196 13 103 and
from international patent application WO 95/27775. Bleach-boosting
transition metal complexes, more particularly with the central atoms Mn,
Fe, Co. Cu, Mo. V, Ti and/or Ru, are used in typical quantities, preferably in
a quantity of up to 1 % by weight, more preferably in a quantity of 0.0025%
by weight to 0.25% by weight and most preferably in a quantity of 0.01 % by
weight to 0.1 % by weight, based on the preparation as a whole.
r CA 02300786 2000-03-16
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The enzymes optionally present in the detergents according to the
invention include proteases, amylases, pullulanases, cellulases, cutinases
andlor lipases, for example proteases, such as BLAP~, Optimase~,
Opticlean~, Maxacal~, Maxapem~, Durazym~, Purafect~OxP,
Esperase~ andlor Savinase~, amylases, such as Termamyl~, Amylase-
LT~, Maxamyl~, Duramyl~, Purafect~OxAm, cellulases, such as
Celluzyme~, Carezyme~, KAC~ andlor the cellulases and lipases known
from International patent applications WO 96134108 and WO 96134092,
such as Lipolase~, Lipomax~, Lumafast~ and/or Lipozym~. The enzymes
used may be adsorbed to supports and/or embedded in shell-forming
materials for protection against premature inactivation, for example as
described in International patent applications WO 92111347 or WO
94123005. They are present in detergents according to the invention in
quantities of preferably up to 10% by weight and, more preferably, from
0.05% by weight to 5% by weight, enzymes stabilized against oxidative
degradation, as known for example from International patent applications
WO 94102597, WO 94102618, WO 94118314, WO 94/23053 or WO
95107350, being particularly preferred.
Suitable stabilizers, especially for per compounds and enzymes
sensitive to heavy metal ions, are the salts of polyphosphonic acids, more
particularly 1-hydroxyethane-1,1-diphosphonic acid (HEDP), diethylene-
triamine pentamethylenephosphonic acid (DETPMP) or ethylenediamine
tetramethylene phosphonic acid.
The detergents may also contain components with a positive effect
on the removability of oil and fats from textiles by washing. This effect
becomes particularly clear when a textile which has already hPr?n
repeatedly washed with a detergent according to the invention containing
this oil- and fat-dissolving component is soiled. Preferred oil- and fat-
dissolving components include, for example, nonionic cellulose ethers,
such as methyl cellulose and methyl hydroxypropyl cellulose containing 15
CA 02300786 2000-03-16
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to 30% by weight of methoxyl groups and 1 to 15% by weight of hydroxy-
propoxyl groups, based on the nonionic cellulose ether, and the polymers
of phthalic acid andlor terephthalic acid known from the prior art or
derivatives thereof, more particularly polymers of ethylene terephthalates
andlor polyethylene glycol terephthalates or anionically and/or nonionically
modified derivatives thereof. Of these, the sulfonated derivatives of
phthalic acid and terephthalic acid polymers are particularly preferred.
Where the detergents are used in washing machines, it can be of
advantage to add typical foam inhibitors to them. Suitable foam inhibitors
are, for example, soaps of natural or synthetic origin which have a high
percentage content of C~a_24 fatty acids. Suitable non-surface-active foam
inhibitors are, for example, organopolysiloxanes and mixtures thereof with
microfine, optionally silanized, silica and also paraffins, waxes,
microcrystalline waxes and mixtures thereof with silanized silica or bis-
stearyl ethylenediamide. Mixtures of different foam inhibitors, for example
mixtures of silicones, paraffins and waxes, may also be used with
advantage. The foam inhibitors, more particularly silicone- and/or paraffin-
containing foam inhibitors, are preferably fixed to a granular water-soluble
or water-dispersible support. Mixtures of paraffins and bis-stearyl
ethylenediamides are particularly preferred.
The function of redeposition inhibitors is to keep the soil detached
from the fibers suspended in the wash liquor and thus to prevent the soil
from being re-absorbed by the washing. Suitable redeposition inhibitors
are water-soluble, generally organic colloids, for example the water-soluble
salts of polymeric carboxylic acids, glue, gelatine, salts of ether carboxylic
acids or ether sulfonic acids of starch or cellulose or salts of acidic
sulfuric
acid esters of cellulose or starch. Water-soluble polyamides containing
acidic groups are also suitable for this purpose. Soluble starch
preparations and other starch products than those mentioned above, for
example degraded starch, aldehyde starches, etc., may also be used.
CA 02300786 2000-03-16
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Polyvinyl pyrrolidone, especially in the form of PVP granules, is preferably
used in the detergents according to the invention. Cellulose ethers, such
as carboxymethyl cellulose (sodium salt), methyl cellulose, hydroxyalkyl
cellulose, and mixed ethers, such as methyl hydroxyethyl cellulose, methyl
hydroxypropyl cellulose, methyl carboxymethyl cellulose and mixtures
thereof, are also preferably used. Redeposition inhibitors, such as PVP,
are normally used in quantities of 0.1 to 5% by weight, based on the
detergent.
The detergents may contain derivatives of diaminostilbene disulfonic
acid or alkali metal salts thereof as optical brighteners. Suitable optical
brighteners are, for example, 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 contain a diethanolamino group, a methylamino group and
anilino group or a 2-methoxyethylamino group instead of the morpholino
group. Brighteners of the substituted Biphenyl styryl type, for example
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, may
also be present. Mixtures of the brighteners mentioned may also be used.
In addition to the ingredients mentioned, the detergents may also
contain other known additives typically used in laundry detergents,
dishwashing detergents and cleaners, for example small quantities of
neutral filler salts and dyes and perfumes, opacifiers or pearlizers.
The bulk density of the advantageously granular detergents is
preferably at least about 600 gll and more preferably from 650 to 1100 g/l.
However, detergents with a lower bulk density may also readily be
produced. This can be particularly preferred where the detergents are
assembled from granular individual components on the building block
principle. High bulk densities above 750 gll are preferably achieved when
the compacting steps described above are applied.
CA 02300786 2000-03-16
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Examples
To produce anionic surfactant granules according to the invention, a
surfactant paste of alkyl(ene) sulfate (FAS) and a-sulfofatty acid methyl
ester (MES) was prepared and homogenized in a mixer. The pH of the
paste was then adjusted to a value of 7 with citric acid. The paste was then
sprayed in a fluidized bed granulator (Glatt AGT 400) into which zeolite X
was simultaneously introduced as carrier.
In all the Examples according to the invention (E1-E3), a-sulfofatty
acid methyl esters of C~4~~s fatty acids were used as the a-sulfofatty acid
methyl esters. A C~2_,8 alkyl sulfate (Sulfopon 1218G~, a product of
Henkel KGaA) was used as the FAS in E1 and E2; an oleyllcetyl alcohol
sulfate (Sulfopon O 680~, a product of Henkel KGaA) was used in E3. In
Examples E2 and E3, alkyl benzenesulfonate was used in addition to the
homogeneous MESIFAS paste - sodium dodecyl benzenesulfonate
(Maranil A 55~, a product of Henkel KGaA) was sprayed into the fluidized
bed separately from the FASIMES paste through a three-component
nozzle. In all Examples, Wessalith XD~ (a product of Degussa AG) was
used as the zeolite X.
FAS granules (Sulfopon 1218G~, a product of Henkel KGaA) were
produced as Comparison Example C.
Free-flowing granules with the compositions shown in Table 1 were
obtained. The particle size distribution was measured at the exit of the
fluidized bed; no coarse particles were removed by sieving.
All the granules produced in accordance with the invention can be
handled in air without becoming tacky or losing their flowability and dissolve
quickly.
CA 02300786 2000-03-16
36
Table 1:
Composition and properties of the granules
E1 E2 E3 C
FAS content % b wei ht 32 17 18 90
MES content % b wei ht 31 22 21 -
ABS content % b wei ht - 12 23 -
Zeolite X content % b wei ht 23 33 29 5
Disalt content % b wei ht 2 2 2 -
Other salts/or . const. % b 7 9 2 4
wei ht
Water % b wei ht 5 5 5 1
Particle size distribution
% b weight
< 0.2 mm n.a. 1.1 0.0 0
>0.2 mm n.a. 30.8 0.5 0
<0.4 mm 1.0 n.a. n.a. n.a.
>0.4 mm 1.3 44.2 9.4 11
>0.63 mm 0.8 14.4 15.7 19
>0.8 mm 1.8 5.8 31.6 26
>1.0 mm 75.1 3.4 42.1 42
>1.6 mm 20.0 0.3 0.7 2
Bulk densit /I 590 630 630 610
Krafft oint C 37 38 36 46
L test at 30C residue in % <5 <3 <3 65
b wei ht
L test at 20C residue in % - <5 <3 91
b wei ht
n.a.: No measurement was carried out
In order to determine solubility behavior (L test), 8 g of the granules
to be tested were scattered while stirring into a 2 liter glass beaker (800
r.p.m. with a laboratory stirrer/propeller stirrer head centrally arranged 1.5
cm from the bottom of the glass beaker) and stirred for 1.5 minutes at
30°C
and at 20°C. The test was carried out with water having a hardness of
16°d. The wash liquor was then poured off through a sieve (80 Nm). The
. CA 02300786 2000-03-16
~ 37
glass beaker was rinsed out over the sieve with a very little cold water. A
double determination was carried out. The sieves were dried to constant
weight in a drying cabinet at 40°C ~ 2°C and the residue was
weighed out.
The results are also set out in Table 1.
The Krafft point was determined by turbidity measurement in
accordance with DIN 53 918.
