Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02308910 2000-OS-19
A Process for the Production of Surfactant Granules
Field of the Invention
This invention relates to a two-stage process for the production of
surfactant granules containing nonionic surfactants.
Background of the Invention
Compacted or highly concentrated detergent powders or tablets
represent a substantial percentage of commercially available detergents.
Such detergents are generally not obtained by a spray drying process, but
rather by mixing, granulation and compacting processes in which high
temperatures are avoided. On account of the relatively low temperatures,
the removal of water introduced by the starting materials is relatively
laborious. In many cases, a drying step has to be carried out on
completion of the granulation process.
Another problem lies in the poor solubility of the relatively heavily
compacted particles. This problem is often encountered in particular with
formulations containing a high percentage of alkoxylated fatty alcohols. An
improvement in solubility can be achieved by incorporating alkyl poly-
glycosides in the granules. However, the incorporation of the alkyl poly-
glycosides is problematical because they cannot be processed by spray
drying processes and the resulting particles are extremely tacky. In
addition, the use of alkyl polyglycosides as a paste in the granulation
process leads to extremely tacky products, particularly in the case of
granules with a high alkyl benzenesulfonate content.
The processed polyglycoside pastes have a water content of around
50% by weight from their production. Accordingly, to produce dry, i.e. non
tacky, and dust-free granules, the water has to be almost completely
removed.
The removal of water often leads to granules with a variable water
content. If the granules are to be further processed to tablets which are
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expected to show rapid and constant solubility in water, the use of granules
with a variable water content can lead to tablets with variable dissolving
rates.
The production of surfactant granules for use in detergents is known
from the prior art. Thus, EP-A-0 859 048 describes a process for the
production of surfactant granules with bulk densities above 600 gll by
granulating a surfactant preparation, in which solutions of alkyl benzene-
sulfonate andlor alkyl polyglycoside surfactants and carrier materials in a
non-surfactant solvent are simultaneously sprayed through one and the
same nozzle and dried in conventional dryers, preferably in a fluidized bed
dryer or in a ring mixer dryer. The carrier materials used are polycarboxy-
lates and inorganic carriers, more particularly amorphous silicates.
International patent application WO 97103165 describes a process
for the production of sugar surfactant granules, i.e. granules containing
alkyl andlor alkenyl oligoglycosides andlor fatty acid-N-alkyl poly
hydroxyalkylamides. In the described process, water-containing pastes of
the components mentioned are granulated in the presence of zeolites
andlor waterglasses and dried either at the same time or in a subsequent
step. The document in question also gives an example of the granulation
of a water-free mixture of an alkyl oligoglycoside and an alkoxylated fatty
alcohol.
International patent application WO 97!09415 discloses a process
for the production of a non-spray-dried particulate surfactant composition
which has a bulk density of at least 600 gll and which contains a polymeric
builder component andlor a soil-release polymer. The granulation liquid
and solid constituents are mixed in a granulator and the polymer is added
in admixture with a non-aqueous diluent during the granulation step. An
ethoxylated nonionic surfactant is preferably used as the non-aqueous
diluent.
International patent application WO 97!02338 discloses a process
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for the production of particulate surfactant compositions with a bulk density
below 700 gll. To produce the surfactant composition disclosed in this
document, a particulate starting material which contains at least 10% by
weight of a component with a bulk density of not more than 600 gll and
which is not a surfactant compound is mixed with a liquid binder in a
granulator and then granulated. The particulate starting material contains a
builder. Surfactant or a surfactant precursor is present in the particulate
starting material andlor in the binder.
International patent application WO 97!22685 discloses a process
for the production of particulate detergent compositions with bulk densities
of 300 to 1300 gll. In the process disclosed in this document, particulate
starting material is mixed with a liquid binder and partly granulated. The
partly granulated mixture is transferred to a less shear-intensive granulator,
more liquid binder is added and the granulation process is continued until a
particulate powder with the required bulk density is obtained. Water,
anionic surfactant, nonionic surfactant or mixtures thereof may be used as
the liquid binder.
European patent application 0 799 884 describes a process for the
production of free-flowing particulate surfactant compositions containing
alkyl polyglycosides in which a concluding drying step is said to be
unnecessary. To carry out the described process, a mixture of a water-
containing alkyl polyglycoside paste, an ethoxylated nonionic surfactant
and a solid water-soluble inorganic salt is initially prepared. The mixture
obtained separates into an organic phase and a water-rich phase, the
organic phase containing alkyl polyglycoside, ethoxylated nonionic surfac-
tant and water being separated off. The percentages of the individual
components in the first step is selected so that the ratio of alkyl polyglyco-
side to ethoxylated nonionic surfactant in the organic phase is in the range
from 35:65 to 65:35 and the ratio of ethoxylated nonionic surfactant to the
total quantity of water is in the range from 90:10 to 60:10. To produce the
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surfactant compositions, the mixture obtained and, optionally, other
surfactants are mixed with one or more particulate carrier materials and the
resulting mixture is processed in a conventional high-speed mixer or
granulator to form a particulate product.
The processes described above have the disadvantage that they are
either very complicated to carry out or lead to non-free-flowing products
with - in some cases - poor solubility.
The problem addressed by the present invention was to provide a
process for the production of surfactant granules which would not be
attended by the disadvantages mentioned above. More particularly, the
present invention set out to provide a process which would give granules
characterized by good and constant solubility. In addition, the granules
obtained would show such favorable free flow behavior that there would be
no need for an additional drying step.
Description of the Invention
It has now surprisingly been found that, if - in a two-stage
granulation process - a fine-particle compound of alkyl polyglycoside on a
suitable carrier is initially prepared and is then granulated in a second step
in the presence of a liquid surfactant and optionally other detergent
ingredients, free-flowing granules with good dissolvability are obtained
without a drying step.
Accordingly, the present invention relates to a process for the
production of surfactant granules containing nonionic surfactants and other
detergent ingredients, characterized in that
A) in a first process step, sugar surfactants are processed in the presence
of water-soluble carrier materials to form a compound and
B) the compounds obtained in A) are mixed with a non-aqueous solvent
and the resulting mixture and optionally other detergent ingredients are
granulated by methods known per se.
The sugar surfactants suitable for use in process step A) may be
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selected in particular from alkyl and alkenyl oligoglycosides and poly-
hydroxyfatty acid amides.
The alkyl and alkenyl oligoglycosides correspond to the following
general formula:
5
R' O(G)x (I)
in which R' is a primary, linear or methyl-branched, more particularly 2-
methyl-branched, alkyl or alkenyl group 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 of 1 to 10; x preferably has a value of 1.2 to 1.4.
Suitable polyhydroxyfatty acid amides are those corresponding to
formula (II):
R3
R2-CO-N-[Z] (I I)
in which RICO is an aliphatic acyl group containing 6 to 22 carbon atoms,
R3 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 known substances which may
normally be obtained by reductive amination of a reducing sugar with
ammonia, an alkylamine or an alkanolamine and subsequent acylation with
a fatty acid, a fatty acid alkyl ester or a fatty acid chloride. Particulars
of
processes for their production can be found in US-A-1,985,424, US-A-
2,016,962 and US-A-2,703,798 and in International patent application WO-
A-92106984. The polyhydroxyfatty acid amides are preferably derived from
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reducing sugars containing 5 or 6 carbon atoms, more particularly glucose.
The sugar surfactants may be used in the form of the aqueous
solutions obtained from the production process. They may also be used in
the form of granules, of which the production is described in WO 97103165,
or in the form of steam-dried products which may be obtained by the
process described in WO 95114519.
The carrier materials used in the first step of the process are
preferably waterglass or water-soluble detergent builders such as, for
example, layer silicates or organic polymers.
Suitable waterglasses are amorphous sodium silicates with an
Na20:Si02 ratio (modulus) of 1:2 to 1:3.3, preferably 1:2 to 1:2.8 and more
preferably 1:2 to 1:2.6. 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
diffraction angle. However, 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
silicates, compounded amorphous silicates and overdried X-ray-amorphous
silicates are particularly preferred.
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Suitable, crystalline layer-form sodium silicates correspond to the
general formula NaMSiX02X+~A y H20, 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 ~- and 8-sodium
disilicates Na2Si205A y H20 are particularly preferred, ~i-sodium disilicate
being obtainable, for example, by the process described in International
patent application WO-A-91108171.
Useful organic carrier materials 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 which bear
more than one acid function. Examples of such carboxylic acids are citric
acid, adipic acid, succinic acid, glutaric acid, malic acid, tartaric acid,
malefic
acid, fumaric acid, sugar acids, aminocarboxylic acids, nitrilotriacetic acid
(NTA), providing their 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 also typically have the property of an acidifying component and,
hence, also serve to establish a relatively low and mild pH value in
detergents. Citric acid, succinic acid, glutaric acid, adipic acid, gluconic
acid and mixtures thereof are particularly mentioned in this regard.
Other suitable builders are polymeric polycarboxylates such as, for
example, the alkali metal salts of polyacrylic 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
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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 higher than the molecular weights mentioned in this specification.
Particularly suitable polymers are 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
g/mole 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 acid. Acrylic acid/maleic 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 g/mole,
preferably in the range from 20,000 to 50,000 g/mole and more preferably
in the range from 30,000 to 40,000 g/mole.
The (co)polymeric polycarboxylates may be used either in powder
form or in the form of an aqueous solution. The content of (co)polymeric
polycarboxylates in the detergent is preferably from 0.5 to 20% by weight
and more preferably from 3 to 10% by weight.
In order to improve solubility in water, the polymers may also contain
allyl sulfonic acids, such as allyloxybenzene sulfonic acid and methallyl
sulfonic acid (cf. for example EP-B-727 448), as monomer.
Other particularly preferred polymers are biodegradable polymers of
more than two different monomer units, for example those which contain
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salts of acrylic acid and malefic acid and vinyl alcohol or vinyl alcohol
derivatives as monomers in accordance with DE-A-43 00 772 or those
which contain salts of acrylic acid and 2-alkylallyl sulfonic acid and sugar
derivatives as monomers in accordance with DE-C-42 21 381.
Other preferred copolymers are those which are described in
German patent applications DE-A-43 03 320 and DE-A-44 17 734 and
which preferably contain acrolein and acrylic acid/acrylic acid salts or
acrolein and vinyl acetate as monomers.
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 sirups 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 92/18542, WO 93108251, WO 93/16110, WO 94128030, WO 95107303,
WO 95112619 and WO 95120608. An oxidized oligosaccharide
corresponding to German patent application DE-A-196 00 018 is also
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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. Ethylenediamine-
5 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 and US 4,639,325, in European patent
application EP-A-0 150 930 and in Japanese patent application JP
10 931339896 are also preferred in this connection. The quantities used in
zeolite-containing and/or 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.
Other suitable carrier materials are oxidation products of
polyglucosans containing carboxyl groups andlor water-soluble salts
thereof which are described, for example, in International patent application
WO-A-93!08251 or which the production is described, for example, in
International patent application WO-A-93116110. Oxidized
oligosaccharides according to German patent application DE 196 00 018
are also suitable.
Other preferred builders are polymeric aminodicarboxylic acids, salts
or precursors thereof. Particular preference is attributed to polyaspartic
acids or salts and derivatives thereof which, according to German patent
application DE-A-195 40 086, are also said to have a bleach-stabilizing
effect in addition to their co-builder properties.
Other suitable builders are polyacetals which may be obtained by
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reaction of dialdehydes with polyol carboxylic acids containing 5 to 7
carbon atoms and at least 3 hydroxyl groups, 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.
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 the sodium salt, the disodium salt showing a
neutral reaction and the tetrasodium salt an alkaline reaction (pH 9).
Preferred aminoalkane phosphonates are ethylenediamine tetramethylene
phosphonate (EDTMP), diethylenetriamine pentamethylenephosphonate
(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 or as the hepta- and octasodium salts of DTPMP. Of the
phosphonates, HEDP is preferably used as a builder. In addition, the
aminoalkane phosphonates have a pronounced heavy metal binding
capacity. Accordingly, it can be of advantage, particularly where the
detergents also contain bleach, to use aminoalkane phosphonates, more
particularly DTPMP, or mixtures of the phosphonates mentioned.
In addition, any compounds capable of forming complexes with
alkaline earth metal ions may be used as co-builders.
Compounds with a particle size of preferably at most 1 mm, more
preferably at most 0.8 mm and most preferably at most 0.4 mm are
obtained in the first step A) of the process. If coarser particles are formed,
they may be ground and reduced to the required particle size in a mill
following the first process step.
The first step of the process is preferably carried out in a
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conventional fluidized bed granulator andlor steam dryer.
In the second step B) of the process, the compounds obtained in
step A) are mixed with a non-aqueous solvent and the resulting mixture
and optionally other detergent ingredients are granulated by methods
known per se.
Preferred non-aqueous solvents are compounds which are liquid at
a temperature of about 80°C, preferably at a temperature of 40°C
and more
preferably at room temperature and which additionally have detersive
properties. Liquid nonionic surfactants are particularly preferred.
It has proved to be suitable for carrying out the process according to
the invention initially to dissolve or suspend the compounds in the liquid
nonionic surfactants. Other ingredients normally present in detergent
granules may also be added at this stage.
The liquid nonionic surfactant preferably used as solvent in
step B) is preferably a fatty alcohol alkoxylate. Particularly suitable
nonionic surfactants 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 group may be linear or, preferably, methyl-branched in
the 2-position or may contain linear and methyl-branched groups in the
form of the mixtures typically present in oxoalcohol groups. However,
alcohol ethoxylates containing linear groups 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 EO, C9_» alcohols containing 7 EO, C~3-~5 alcohols
containing 3 EO, 5 EO, 7 EO or 8 EO, C~2_~$ alcohols containing 3 EO, 5
EO or 7 EO and mixtures thereof, such as mixtures of C~z_~a alcohol
containing 3 EO and C~2_~a alcohol containing 7 EO. The degrees of
ethoxylation mentioned represent statistical mean values which, for a
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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 EO, 16 EO, 20 EO, 25 EO, 30 EO or 40 EO.
The granulation process may be carried out in a number of
machines typically used in the detergent industry. For example, the
spheronizers commonly used in the pharmaceutical industry may be used.
In machines such as these, the residence time of the granules is normally
less than 20 seconds. Conventional mixers and mixerlgranulators may
also be used for the granulation process. Suitable mixers are both high-
shear mixers and also normal mixers operating at relatively low rotational
speeds. Suitable mixers are, for example, Series R or RV Eirich~ mixers
(trademarks of Maschinenfabrik Gustav Eirich, Hardheim), the Schugi~
Flexomix, the Fukae~ FS-G mixers (trademarks of Fukae Powtech, Kogyo
Co., Japan), Lodige~ FM, KM and CB mixers (trademarks of Lodige
Maschinenbau GmbH, Paderborn) and Series T or K-T Drais~ mixers
(trademarks of Drais-Werke GmbH, Mannheim). In all these mixers and
spheronizers, the particles are converted into granules by liquid bridge
binding of the non-aqueous binders. The residence times of the granules
in the mixers is less than 60 seconds, the residence time also depending
on the rotational speed of the mixer. The residence times are shorter, the
faster the rotational speed of the mixer. The residence times of the
granules in mixerslspheronizers are preferably less than 1 minute and
more preferably under 15 seconds. In low-speed mixers, for example
Lodige KM mixers, the residence times are up to 20 minutes, residence
times of less than 10 minutes being preferred in the interests of process
economy.
In the press agglomeration process, the surfactant-containing
granules are compacted under pressure and under the effect of shear
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forces and, at the same time, homogenized and are then discharged from
the machines via a shapinglforming stage. Industrially the most important
press agglomeration processes are extrusion, roller compacting, pelleting
and tabletting. Press agglomeration processes preferably used in
accordance with the present invention for producing the surfactant-
containing granules are extrusion, roller compacting and pelleting.
The product obtained on completion of the granulation process is dry
and does not have to be subjected to another drying step.
In order further to improve their processability and "dosability", the
granules obtained may be powdered with an oil absorption component. As
a result of this concluding powdering step using a fine-particle component,
the liquids are fixed to the surface of the granules so that the granules are
unable to form lumps in storage. The oil absorption component should
have an oil absorption capacity of at least 20 g1100 g, preferably of at least
50 g1100 g, more preferably of at least 80 g1100 g, more preferably of at
least 120 81100 g and, in one particular embodiment, of at least 140 81100
g.
The oil absorption capacity is a physical property of a substance
which can be measured by standardized methods. For example British
Standards BS1795 and BS3483:Part B7:1982, which both refer to ISO
787!5, are available. In these test methods, a weighed sample of the
particular substance is applied to a dish and refined linseed oil (density:
0.93 gcm)3) is added dropwise from a burette. After each addition, the
powder is intensively mixed with the oil using a spatula, the addition of oil
being continued until a paste of flexible consistency is obtained. This paste
should flow without crumbling. Now, the oil absorption capacity is the
quantity of oil added dropwise, based on 100 g of absorbent, and is
expressed in m1/100 g or 81100 g, conversions via the density of the linseed
oil readily being possible.
The oil absorption component preferably has a small mean particle
' CA 02308910 2000-OS-19
size because the active surface increases with decreasing particle size.
Preferred detergent tablets contain a component with an oil absorption
capacity of at least 20 g1100 g which has a mean particle size below 50
Nm, preferably below 20 Nm and more preferably below 10 Nm.
5 The oil absorption component may be selected from a number of
substances. There are many inorganic and organic substances which have
a sufficiently large oil absorption capacity. Fine-particle materials obtained
by precipitation are mentioned by way of example in this regard. Suitable
oil absorption components are, for example, silicates, alumosilicates,
10 calcium silicates, magnesium silicates and calcium carbonate. However,
kieselghur (diatomaceous earth) and fine-particle cellulose fibers or
derivatives thereof may also be used in accordance with the invention.
Preferred detergent tablets are characterized in that the component
present in them with an oil absorption capacity of at least 20 g1100 g is
15 selected from silicates and/or alumosilicates, more particularly from the
group of silicas andlor zeolites. These include, for example, fine-particle
zeolites and also pyrogenic silicas (Aerosil~) or precipitated silicas.
Other surfactants, more particularly anionic surfactants, and builders
may be incorporated in the surfactant granules as additional components.
In one preferred embodiment, the other components are incorpo-
rated in the form of a spray-dried powder in the second step of the process.
Temperature-sensitive or water-sensitive components may be separately
added.
Suitable builders are any builders suitable for detergents which have
a sufficiently large inner surface to be able to absorb the nonionic
surfactant. Examples of such builders are zeolites, amorphous silicates,
soda, phosphates and mixtures thereof, zeolite being preferred.
The zeolite used may be, for example, finely crystalline synthetic
zeolite containing bound water, such as zeolite A, zeolite P and mixtures of
A and P. An example of a commercially available zeolite P is zeolite
CA 02308910 2000-OS-19
16
MAP~ (a Crosfield product).
Zeolites of the faujasite type are mentioned as other preferred and
particularly suitable zeolites. Together with zeolites X and Y, the mineral
faujasite belongs to the faujasite types within zeolite structure group 4
which is characterized by the double 6-membered ring subunit D6R (cf.
Donald W. Breck: "Zeolite Molecular Sieves", John Wiley & Sons, New
York, London, Sydney, Toronto, 1974, page 92). Besides the faujasite
types mentioned, the minerals chabasite and gmelinite and the synthetic
zeolites R (chabasite type), S (gmelinite type), L and ZK-5 belong to zeolite
structure group 4. The last two of these synthetic zeolites do not have any
mineral analogs.
Faujasite zeolites are made up of ~i-cages tetrahedrally linked by
D6R subunits, the ~i-cages being arranged similarly to the carbon atoms in
diamond. The three-dimensional framework of the faujasite zeolites used
in the process according to the invention has pores 2.2 and 7.4 A in size.
In addition, the elementary cell contains eight cavities each ca. 13 A in
diameter and may be described by the formula Na86[(A102)as(Si02)~os] ~ 264
H20. The framework of the zeolite X contains a void volume of around
50%, based on the dehydrated crystal, which represents the largest empty
space of all known zeolites (zeolite Y: ca. 48% void volume, faujasite: ca.
47% void volume). (All data from: Donald W. Breck: "Zeolite Molecular
Sieves", John Wiley & Sons, New York, London, Sydney, Toronto, 1974,
pages 145, 176, 177).
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 also be used in
addition to zeolite X although pure zeolite X is preferred. Mixtures or co-
crystallizates of faujasite zeolites with other zeolites, which do not
necessarily have to belong to zeolite structure group 4, may also be used in
- CA 02308910 2000-OS-19
17
accordance with the invention, the advantages of the process according to
the invention coming to light particularly clearly when at least 50% by
weight of the zeolites are faujasite zeolites.
The aluminium silicates used in the process according to the
invention are commercially obtainable and the methods for their production
are described in standard works.
Examples of commercially available X-type zeolites may be
described by the following formulae:
Nass[(A102)8s(Si02)ios] ~ x H20,
K8s[(AIO2)ss(Si02Oos] ~ x H20,
Ca4oNas[(A102)8s(Si02)~os] ~ x H20,
Sr2~Ba22[(A102)$s(Si02)~os] ~ x H20,
in which x may assume a value of 0 to 276 and which have pore sizes of
8.0 to 8.4 A.
For example, a co-crystallizate of zeolite X and zeolite A (ca. 80% by
weight zeolite X), which is marketed by CONDEA Augusta S.p.A. under the
name of VEGOBOND AX~ and which may be described by the following
formula:
nNa20 ~ (1-n)K20 ~ AI203 ~ (2 - 2.5)Si02 (3.5 - 5.5) H20
is commercially obtainable and may be used with advantage in the process
according to the invention.
Zeolites of the Y type are also commercially obtainable and may be
described, for example, by the following formulae:
CA 02308910 2000-OS-19
18
Na56I(AIO2)56(SIOz)136~ ' X I"'12~,
K56L(AIO2)56(SIO2)136~ ' x H20,
in which x is a number of 0 to 276 and which have pore sizes of 8.0 A.
The particle sizes of the faujasite zeolites used in the process
according to the invention is in the range from 0.1 to 100 pm, preferably in
the range from 0.5 to 50 Nm and more preferably in the range from 1 to 30
Nm, as measured by standard methods for determining particle size.
Besides the nonionic surfactants used in accordance with the
invention, the detergents according to the invention may also contain
anionic surfactants such as, for example, C$_ZZ alkyl sulfates, C8_22 alkane-
sulfonates, C8_22 olefin sulfonates, C8_22 alkyl benzenesulfonates, C$_22
fatty
acid ether sulfates, C8_22 fatty acid ester sulfonates, sulfonated fatty acid
glycerol esters, 2,3-C8_22-alkyl sulfates, salts, monoesters andlor diesters
of
alkylsulfosuccinic acid (sulfosuccinates), sulfuric acid monoesters of linear
or branched C~_2~ alcohols ethoxylated with 1 to 6 moles ethylene oxide,
fatty acid soaps and mixtures thereof.
The detergents according to the invention may additionally contain
any substances typically present in detergents, such as inorganic salts,
bleaching agents, bleach activators, redeposition inhibitors, foam inhibitors,
salts of polyphosphonic acids, optical brighteners, enzymes and mixtures
thereof.
The granules produced in accordance with the invention may either
be used as sole detergent component or may be mixed and compounded
with other particles containing other detergent ingredients.
In one preferred embodiment, the granules are mixed with other
detergent ingredients and the resulting mixture is tabletted to form
detergent tablets.
CA 02308910 2000-OS-19
19
Embodiments of the Invention are described by reference to the
following Example which is not to be construed as limiting.
Examples
A sugar surfactant compound with the composition shown in Table 1
was produced in the first step of the process carried out in a fluidized bed
granulator by spraying a 50% alkyl polyglycoside paste and a 40%
Sokalan~ solution (acrylic acidlmaleic acid copolymer, product of BASF
AG, Ludwigshafen). The product obtained was then ground in a mortar mill
to a maximum particle size of 0.1 mm.
In the next granulation step, a powder obtained by spray drying with
the composition shown in Table 2, C~2_~$ alkyl sulfate and sodium citrate
were introduced into a 130 I Lodige mixer in the quantities shown in Table
3. A mixture of nonionic surfactant and the compound produced in the first
step of the process was added in the quantities shown in Table 3 and
granulated. On completion of the granulation process, the granules were
powdered with 3% Wessalith~ XD (zeolite, a product of Degussa AG,
Hanau).
In Comparison Example 1, the powder was granulated with a
mixture of nonionic surfactant and glycerol; in Comparison Example 2, only
nonionic surfactant was used. The granules obtained were sieved to a
particle size of 0.6 to 1.6 mm. The granules with a particle size of 0.6 to
1.6 mm are referred to in Table 4 as "accepts". The granules obtained did
not have to be dried.
The solubility of the products was tested by the so-called L Test. To
this end, 8 g of substance were added to 1000 ml of water with a hardness
of 16°dH at 30°C and stirred with a propeller stirrer for 1.5
minutes at 800
r.p.m. The undissolved solids were sieved on a 0.2 mm mesh sieve. The
residue was dried to constant weight and weighed. The test results are set
out in Table 4.
CA 02308910 2000-OS-19
Table 1:
Composition of the APG compound in
C~z-~a alkyl polyglucoside 50
with x = 1.3
Sokalan CP5~ 45
Water, salts 5
Table 2:
Composition of the tower powder in
C,2_~8 alkyl benzenesulfonate22.8
Tallow alcohol ~ 5 EO 1.3
C~z_~$ fatty acid soap 1.3
Sodium sulfate 4
Zeolite A 48
Phosphonate 1
Sokalan~ CP5' 8
NaOH 0.5
Water,salts Balance
Acrylic acidlmaleic acid copolymer, product of BASF AG, Ludwigshafen
Table 3:
Granulation mixtures in %, 8 kg total quantity
E1 C1 C2
Tower powder 73 73 73
Sulfopon~ 1218G' 6 6 6
Na citrate 6 6 6
CA 02308910 2000-OS-19
21
Dehydol~ LT 7 9.2 9.2 12
APG compound 2.8 I I
Glycerol, 86% I 2.8 I
Wessalith XD 3 3 3
Compound containing 92% C12-18 fatty alcohol sulfate (a product of
Henkel KGaA)
C~2,~$ fatty alcohol ~ 7 EO (a product of Henkel KGaA)
Table 4:
Data of the granules
E1 C1 C2
Fraction > 1.6 in 12 6 8
%
Fraction < 0.6 in 39 49 42
%
"Accepts" in % 49 45 50
Bulk density in gll 690 610 660
~L Test 1.5 mins. 3 10 16
~
The results set out in Table 4 show that the accepts and the bulk
density of the granules produced in accordance with the invention and the
granules of the Comparison Examples are in similar ranges. However, the
solubility of the granules produced in accordance with the invention is
distinctly better than that of the comparison granules.
