Note: Descriptions are shown in the official language in which they were submitted.
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H 3957IH3957-I 1
A Builder-containing Tablet
This invention relates to builder-containing tablets containing
crystalline layer silicates which are suitable for washig or cleaning or for
softening water.
Tablets have a number of advantages over powders, including easy
dosing and minimal packaging volume. However, problems arise out of the
fact that relatively high tabletting pressures have to be applied in the
tabletting of the powders in order to achieve adequate dimensional stability
and fracture resistance. On account of the high compression to which they
are subjected, therefore, tablets often have unsatisfactory disintegrating
and dissolving properties in use. In order to be able to control problems
such as these, tabletting aids are generally added to the actual active
substances. The tabletting aids in question are, for example, polyethylene
glycols, typically with molecular weights of 1000 to 6000 g/mole, which
normally make up from 2 to 6% by weight of the tablet formulation as a
whole. In addition, to ensure that the tablets dissolve rapidly, so-called
disintegrators are added. These disintegrators, which are normally used in
quantities of 3 to 30% by weight of the tablets, include for example
microcrystalline cellulose and swellable synthetic polymers, such as
polyvinyl pyrrolidone. Both the tabletting aids and the disintegrators are
additives which do not themselves contribute towards the effect of the
particular tabletted composition. Accordingly, such additives reduce the
active-substance content of the tablets.
Accordingly, there is still a need for active substances which also act
as tabletting aids or disintegrators and thus eliminate the need for special
tabletting aids and disintegrators.
It has now been found that tablets in which crystalline layer silicates
and certain copolymers are present in the form of a suitably prepared
' . CA 02302141 2000-03-27
H 3957/H3957-I 2
compound do not have to contain further auxiliaries of the type in question
and can still be produced with relatively low tabletting pressures without
any adverse effect on their fracture resistance. The tablets show excellent
dissolving behavior, even in the absence of special disintegrators.
Tablets containing crystalline layer silicates have long been known
per se. Patent application WO 95121908 describes tablets containing
amorphous, partly crystalline and/or crystalline layer-form sodium silicates
with the following formula:
Na2Six02X.., ~yH20
where x is a number of 1.9 to 4 and y is a number of 0 to 20, in quantities of
2 to 100% by weight. A water softening tablet described in this application
contains, for example, 20 to 80% by weight of the crystalline layer silicates,
optionally up to 80% by weight of zeolite and/or phosphate, optionally up to
50% by weight of polycarboxylate, up to 15% by weight of polymeric poly-
carboxylates and up to 30% by weight of surfactants. The tablet described
in one Example contains methyl hydroxypropyl cellulose as disintegrator.
EP-A-812 808 describes water softening tablets which may contain
up to 45% by weight of crystalline layer silicates and which additionally
contain a polybasic carboxylic acid or salt, carbonate andlor bicarbonate
and polymer. The tablets also contain 1 to 6% by weight of binder and up
to 15% by weight of disintegrator.
It has now been found that tablets which, besides other ingredients,
contain a granular additive which in turn contains a crystalline layer
silicate
and (co)polymeric polycarboxylic acid as key ingredients can be produced
at moderate tabletting pressures, even without the use of additional
tabletting aids or disintegrators, and are readily soluble.
In a first embodiment, therefore, the present invention relates to
tablets containing builders and optionally other ingredients of detergents or
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H 3957JH3957-I 3
to phases of such tablets, characterized in that they contain a powder-form
or granular additive which contains a crystalline layer silicate corresponding
to general formula (I):
NaMSiX02X+~ ~ yHzO (I)
in which M is sodium or hydrogen, x is a number of 1.9 to 2.2 and y is a
number of 0 to 33,
and (co)polymeric polycarboxylic acid as key ingredients, the tablets
containing no additional disintegrator without a builder effect and at most
2% by weight of additional tabletting aid.
Crystalline layer silicates corresponding to formula (I) are marketed,
for example, by Clariant GmbH (Germany) under the trade name Na-SKS,
including for example Na-SKS-1 (Na2Si220a5~xH20, kenyaite) Na-SKS-2
(Na2Si,4029.xH20, magadiite), Na-SKS-3 (Na2Si80~~~xH20), Na-SKS-4.
(Na2Si409~xH20, makatite).
Compositions particularly suitable for the purposes of the invention
are those containing crystalline layer silicates corresponding to formula (I)
in which x is 2. Of these, Na-SKS-5 (a'-Na2Si205), Na-SKS-7 (~ -NazSi205
natrosilite), Na-SKS-9 (NaHSi205 ~ H20), Na-SKS-10 (NaHSi205 ~ 3H20,
kanemite), Na-SKS-11 (T~-Na2Si205) and Na-SKS-13 (NaHSi205), but
especially Na-SKS-6 ( s-Na2Si205), are particularly suitable. An overview
of crystalline layer silicates can be found, for example, in the articles
published in "Hoechst High Chem Magazin 1411993", pages 33-38 and
in "Seifen-Ole-Fette-Wachse", Vol. 116, No. 20J1990", pages 805-808.
According to the invention, the crystalline layer silicates corresponding to
formula (I) are at least partly introduced into the tablets according to the
invention through the builder additive used in accordance with the
invention. In one preferred embodiment of the invention, the crystalline
layer silicates corresponding to formula (I) are introduced into the tablets
CA 02302141 2000-03-27
H 3957/H3957-I 4
according to the invention solely through the builder additive used in
accordance with the invention. The tablets advantageously contain the
crystalline layer-form silicate corresponding to formula (I) in quantities of
2
to at most 50% by weight, preferably in quantities of 5 to 45% by weight
and more preferably in quantities of 10 to 40% by weight.
In the context of the present invention, a (co)polymeric polycar-
boxylic acid is understood to be a non-neutralized or only partly neutralized
homopolymer or copolymer. These include the homopolymers of acrylic or
methacrylic acid and copolymers thereof with other ethylenically
unsaturated monomers such as, for example, acrolein, dimethyl acrylic
acid, ethyl acrylic acid, vinyl acetic acid, allyl acetic acid, malefic acid,
fumaric acid, itaconic acid, meth(allylsulfonic acid), vinyl sulfonic acid,
styrene sulfonic acid, acrylamidomethyl propane sulfonic acid and
monomers containing phosphorus groups such as, for example, vinyl
phosphonic acid, allyl phosphoric acid and acrylamidomethyl propane
phosphonic acid and salts thereof, and hydroxyethyl (meth)acrylate
sulfates, allyl alcohol sulfates and allyl alcohol phosphates. Polymers such
as these are described, for example, in German patent applications DE-A-
23 57 036, DE-A-44 39 978 and in European patent applications EP-A-0
075 820 and EP-A-0 451 508.
Preferred (co)polymers have an average molecular weight of 1000
to 100,000 glmole, preferably in the range from 2000 to 75,000 glmole and
more preferably in the range from 2000 to 35,000 g/mole. The degree of
neutralization of the acid groups is advantageously between 0 and 90%,
preferably between 10 and 80% and more preferably between 30 and 70%.
Other suitable polymers are, above all, homopolymers of acrylic acid
and copolymers of (meth)acrylic acid with malefic acid or malefic anhydride.
Other suitable copolymers are derived from terpolymers which can
be obtained by polymerization of 10 to 70% by weight of monoethylenically
unsaturated dicarboxylic acids containing 4 to 8 carbon atoms or salts
CA 02302141 2000-03-27
H 39571H3957-I
thereof, 20 to 85% by weight of monoethylenically unsaturated monocar-
boxylic acids containing 3 to 10 carbon atoms or salts thereof, 1 to 50% by
weight of monounsaturated monomers, which release hydroxyl groups on
the polymer chain after saponification, and 0 to 10% by weight of other
radical-copolymerizable monomers. For the purposes of the use according
to the invention, saponification of the monounsaturated monomers, which
release a hydroxyl group on the polymer chain after saponification, is
preferably carried out in a acidic medium. Products of the type mentioned
above are described in German patent applications DE-A-43 00 772 and
DE-A-195 16 957 and in WO-A-94115978.
Graft polymers of monosaccharides, oligosaccharides, polysaccha-
rides and modified polysaccharides, as described in German patent
applications DE-A-40 03 172 and DE-A-4415 623, are also suitable, as are
the graft polymers with proteins of animal or vegetable origin disclosed in
the European patent application, more particularly with modified proteins.
From the group of graft copolymers, copolymers of sugar and other
polyhydroxy compounds and a monomer mixture with the following
composition are preferably used: 45 to 96% by weight of monoethylenically
unsaturated C3_~o monocarboxylic acid or mixtures of C3_1o monocarboxylic
acids andlor salts thereof with polyvalent cations, 4 to 55% by weight of
monomers containing monoethylenically unsaturated monosulfonic acid
groups, monoethylenically unsaturated sulfuric acid esters, vinyl
phosphonic acid and/or the salts of these acids with polyvalent cations and
0 to 30% by weight of water-soluble monoethylenically unsaturated com-
pounds modified with 2 to 50 moles of alkylene oxide per mole of mono-
ethylenically unsaturated compound. Such compounds are described in
DE-A-42 21 381 and in DE-A-43 43 993.
Other suitable polymers are polyaspartic acids and derivatives
thereof in non-neutralized or only partly neutralized form. The polyaspartic
acids normally accumulate in the form of their alkali metal or ammonium
CA 02302141 2000-03-27
H 3957/H3957-I 6
salts. The non-neutralized or only partly neutralized products may be
obtained therefrom by adding appropriate quantities of organic or inorganic
acids and optionally removing the salts formed.
Products of the type in question may also be obtained by the thermal
reaction of malefic acid and ammonia or by the condensation of aspartic
acid and subsequent hydrolysis of the polysuccinimide formed. The
production of products such as these is described, for example, in DE-A-36
26 672, DE-A-43 07 114, DE-A-44 27 287, EP-A-0 612 784, EP-A-0 644
257 and WO-A-92114753.
Graft polymers of acrylic acid, methacrylic acid, malefic acid and
other ethylenically unsaturated monomers with the salts of polyaspartic
acid normally accumulating in the above-described hydrolysis of the
polysuccinimide are also particularly suitable. In their case, there is no
need for the otherwise necessary addition of acid for the production of the
only partly neutralized form of polyaspartic acid. The quantity of
polyaspartate is normally selected so that the degree of neutralization of all
the carboxyl groups incorporated in the polymer does not excess 80%,
preferably 60%. Products of the type mentioned are described in detail in
International patent application WO-A-94101486.
The quantities in which the non-neutralized or only partly neutralized
(co)polymeric polycarboxylates are present in the compositions according
to the invention are determined by the content of builder additives used in
accordance with the invention and by their content of these polymers.
The builder additive used in accordance with the invention contains
the crystalline layer silicate corresponding to formula (I) and the (co)poly
meric polycarboxylic acid in a ratio by weight of preferably (40 to 1 ):1 and
more preferably (20 to 2):1, ratios of 7:1 to about 3:1, based on the water
free active substances, being particularly advantageous. The water
content of the builder additives used in accordance with the invention is
preferably between 4 and 20% by weight, the upper appropriate limit to the
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H 3957/H3957-I 7
water content being made dependent on the fact that the builder additive
should still be stable and free-flowing and should not form any lumps, even
after storage at elevated temperatures of, for example, 40°C. It has
been
found that the lower limit to the water content influences the dissolving
behavior of the builder additive. Accordingly, in the interests of a higher
dissolving rate of the builder additive, additives containing 5 to 15% by
weight of water are preferred, those containing 7 to 12% by weight of water
being particularly preferred. The water content is determined over a period
of 4 hours at a temperature of 140°C.
The builder additives used in accordance with the invention may be
produced simply by contacting the crystalline layer silicate corresponding to
formula (I) with an aqueous solution, preferably a concentrated aqueous
solution, of the (co)polymeric polycarboxylic acid, optionally followed by
drying to the requisite water content. Conventional mixers and granulators,
such as the Lodige plowshare mixer or a Schugi mixer or an Eirich mixer or
a Lodige CB 30 Recycler and other machines known to the expert, which
above all enable a liquid to be sprayed onto a solid, are as suitable as
fluidized bed mixers/granulators. The polymer solution acts as an agglo-
meration aid. It is assumed that, in the reaction of the crystalline layer
silicate corresponding to formula (I) with the acidic polymer, particularly
where the polymer solution used has a pH value below 4, the sodium ions
of the silicate are partly replaced by protons. However, the silicate skeleton
with its layer structure and the majority of the sodium ions remain
unchanged. The effect of this is that the builder additives used in
accordance with the invention have only a slightly reduced starting
alkalinity, but a far lower residual alkalinity than the pure crystalline
layer
silicate corresponding to formula (I). The residual alkalinity may be
adjusted through the polymer acid content of the additives. Accordingly,
the builder additive may be used as a buffer in the dishwasher detergents.
The builder additives may contain large quantities of (co)polymeric
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H 3957/H3957-I g
carboxylic acid, preferably quantities of 2 to 40% by weight, more
preferably quantities of 5 to 30% by weight and most preferably quantities
of 10 to 25% by weight. The content of crystalline layer silicates of formula
(I) in the builder additives is preferably between 50 and 90% by weight,
more preferably between 60 and 90% by weight and most preferably
between 65 and 85% by weight. The additives preferably have a calcium
binding capacity above 185 mg CaCO~/g. The pH value of a 0.1 % by
weight aqueous solution at 20°C is preferably above 10, but below 12.
The
bulk density of the additives used in accordance with the invention varies
according to the method used for their production and is normally above
400 to about 700 g/l. Whereas pure crystalline layer silicate corresponding
to formula (I), such as SKS 6~, normally accumulates in very fine-particle
form and also contains large amounts of dust, the builder additive used in
accordance with the invention is a relatively coarse-particle powder or an
agglomerate or granules which are finer when produced in a fluidized bed
and coarser when produced, for example, in a high-speed mixer. Relative
coarse-particle additives have a mean particle size (d5o), for example of
about 450 to 900 Nm whereas relatively fine-particle additives have a mean
particle size (d5o) of about 280 to 330 Nm. Even in the fine-particle
additives, however, the percentage of dust is far lower than in the
commercially available pure crystalline layer silicates corresponding to
formula (I), more particularly SKS 6~.
The content of these builder additives in the tablets according to the
invention is variable within wide limits and depends upon the function the
tablets are expected for perform. Normal contents of these builder addi
tives are between about 20 and 60% by weight, contents of 25 to 50% by
weight being preferred and contents of up to 45% by weight being particu-
larly preferred.
Disintegrators which, according to the invention, are not intended to
be present in the tablets or in the tablet phases are regarded as auxiliaries
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H 3957/H3957-I 9
which have a positive influence on the dissolving or disintegrating process
in the aqueous phase used, but which otherwise have no effect as a builder
in the tabletted detergent.
According to Rompp (9th Edition, Vol. 6, page 4440) and Voigt
"Lehrbuch der pharmazeutischen Technologie" (6th Edition, 1987,
pages 182-184), tablet disintegrators or disintegration accelerators are
auxiliaries which promote the rapid disintegration of tablets in water or
gastric juices and the release of the pharmaceuticals in an absorbable
form. These substances, which are also known as "disintegrators" by
virtue of their effect, are capable of undergoing an increase in volume on
contact with water so that, on the one hand, their own volume is increased
(swelling) and, on the other hand, a pressure can be generated through the
release of gases which causes the tablet to disintegrate into relatively small
particles.
Well-known disintegrators are, for example, carbonatelcitric acid
systems, although other organic acids may also be used. Besides their
disintegrating effect, however, these systems have a builder effect and,
accordingly, definitely do not belong to the disintegrators which have no
effect in the tabletted composition according to the invention, so that they
may certainly be present in the tablets or tablet phases according to the
invention. Preferred embodiments of the invention actually contain large
amounts of organic carboxylic acids and carbonates. These preferred
embodiments are water-softening tablets which are describe in detail
hereinafter.
Swelling disintegration aids which are not intended to be present in
accordance with the invention are, for example, synthetic polymers, such
as polyvinyl pyrrolidone (PVP), or natural polymers and modified natural
substances, such as cellulose and starch and derivatives thereof, alginates
or casein derivatives.
In particular, no cellulose-based disintegrators should be present in
CA 02302141 2000-03-27
H 3957/H3957-I 10
the tablets or tablet phases according to the invention. Pure cellulose has
the formal empirical composition (CsH~o05)~ and, formally, is a ~i-1,4-
polyacetal of cellobiose which, in turn, is made up of 2 molecules of
glucose. Suitable celluloses consist of ca. 500 to 5000 glucose units and,
accordingly, have average molecular weights of 50,000 to 500,000.
According to the invention, cellulose derivatives obtainable from cellulose
by polymer-analog reactions may also be used as cellulose-based
disintegrators. These chemically modified celluloses include, for example,
products of esterification or etherification reactions in which hydroxy
hydrogen atoms have been substituted. However, celluloses in which the
hydroxy groups have been replaced by functional groups that are not
attached by an oxygen atom may also be used as cellulose derivatives.
The group of cellulose derivatives includes, for example, alkali metal
celluloses, carboxymethyl cellulose (CMC), cellulose esters and ethers and
aminocelluloses. Although compounds such as these certainly develop
effects in the tabletted composition, particularly where it is a laundry
detergent, they are preferably still not present in the tablets or tablet
phases. Microcrystalline cellulose is mentioned as another cellulose-based
disintegrator or as a constituent of that component. This microcrystalline
cellulose is obtained by partial hydrolysis of the celluloses under conditions
which only attack and completely dissolve the amorphous regions (ca. 30%
of the total cellulose mass) of the celluloses, but leave the crystalline
regions (ca. 70%) undamaged. Subsequent de-aggregation of the micro-
fine celluloses formed by hydrolysis provides the microcrystalline celluloses
which have primary particle sizes of ca. 5 um and which can hp
compacted, for example, to granules with a mean particle size of 200 Nm.
Tabletting aids which may be present in the tablets or tablet phases
according to the invention in a quantity of up to at most 2% by weight are
substances which provide for better cohesion of the individual powder-form
or granular constituents and which therefore contribute towards the stability
CA 02302141 2000-03-27
H 3957/H3957-I 11
of the tablet.
In a preferred embodiment, the tablets or tablet phases contain only
dust binding agents as tabletting aids. These include, in particular, short-
chain polyethylene glycols with molecular weights below 800 g/mole and
paraffins, more particularly paraffin oils.
The unwanted tabletting aids include, in particular, polyethylene
glycols with molecular weights of 1000 to 10,000 glmole, starch, cellulose,
starch and cellulose derivatives and also gelatin and polyvinyl pyrrolidone.
Some detergent ingredients, such as certain liquid or paste-form nonionic
surfactants, also act as tabletting aids. Although they may be present in
tablets according to the invention where the tablets are intended to act as
laundry detergents, they are not necessary as tabletting aids. Accordingly,
preferred embodiments of the invention are also free from such nonionic
surfactants.
Tablets or tablet phases containing these ingredients may be
tabletted under moderate pressures and still show high edge abrasion
resistance. At the same time, the tablets are readily soluble, their
solubility
being at least comparable with that of tablets known from the prior art
which can contain both relatively large quantities of tabletting aids and also
the disintegrators described above. In contrast to such tablets, the tablets
or tablet phases according to the invention can accommodate a very high
active substance content because they do not contain these disintegrators
at all and the described tabletting aids in only very small quantities.
Besides the constituents already described, the tablets may contain
other ingredients, preferably substances which have (co)builder properties.
Thus, the tablets may also contain the builders, crystalline sodium layer
silicates and polymeric polycarboxylic acids already mentioned in addition
to the additive, even in separate form. This may be the case above all
when the tablets contain several "phases" or "layers" which have a
homogeneous composition in themselves. In the case of multiphase
CA 02302141 2000-03-27
H 3957/H3957-I 12
tablets of the type in question, it can be preferred for the various phases
which can contain various active substances to dissolve at different rates.
Accordingly, it may be preferred to use the additive in only one phase
according to the invention whPrPa~ fihEa n+hcr nh~~o ...,.,+.,~.,~ ....
disintegrator or another disintegrator. However, it may also be entirely
desirable for the other phases) to contain the same builders, but in a form
which does not have the disintegrating effect of the additive.
The tablets according to the invention may also contain other
builders and co-builders.
Other builders are, primarily, alumosilicates and phosphates. The
alumosilicate is preferably a finely crystalline, synthetic zeolite containing
bound water, more particularly zeolite A, X andlor zeolite P. Zeolite MAP~
(Crosfield), for example, is used as a P-type zeolite. However, zeolite Y
and mixtures of A, X, Y andlor P are also suitable. One such mixture of
zeolite X and zeolite A is marketed by Condea Augusta S.p.A. under the
name of Vegobond AX~. The zeolite may be used as a spray-dried
powder or even as an undried stabilized suspension still moist from its
production. If the zeolite is used in the form of a suspension, the
suspension may contain small additions of nonionic surfactants as
stabilizers, for example 1 to 3% by weight, based on zeolite, of ethoxylated
C,2_~$ fatty alcohols containing 2 to 5 ethylene oxide groups, C~2_~4 fatty
alcohols containing 4 to 5 ethylene oxide groups or ethoxylated
isotridecanols. Suitable zeolites have a mean particle size of less than 10
~.m (volume distribution, as measured by the Coulter Counter Method) and
contain preferably 18 to 22% by weight and more preferably 20 to 22% by
weight of bound water.
Other possible builders are amorphous sodium silicates with a
modulus (NaZO: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
CA 02302141 2000-03-27
H 3957/H3957-I 13
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 rnay 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.
The generally known phosphates may of course also be used as
builders providing their use should not be avoided on ecological grounds.
The sodium salts of the orthophosphates, the pyrophosphates and, in
particular, the tripolyphosphates are particularly suitable. Their content is
generally not more than 25% by weight and preferably not more than 20%
by weight, based on the final composition. In some cases, it has been
found that tripolyphosphates in particular, even in small quantities of up to
at most 10% by weight, based on the final composition, lead to a synergisic
improvement in multiple wash cycle performance in combination with other
builders. It can also be of advantage in this regard to use phosphate in the
form of the phosphate compounds described in earlier German patent
application DE 198 59 807.6.
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H 39571H3957-I 14
Besides the polymeric polycarboxylic acids used in accordance with
the invention, 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, accordingly, 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.
Other suitable builders are polyacetals which may be obtained by
reaction of dialdehydes with polyol carboxylic acids containing 5 to 7
carbon atoms and at least three 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 and/or glucoheptonic acid.
Other suitable co-builders are oxydisuccinates and other derivatives
of disuccinates, preferably ethylenediamine disuccinate. Ethylenediamine
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, US 4,639,325, in European patent application
EP-A-0 150 930 and in Japanese patent application JP 931339896 are also
CA 02302141 2000-03-27
H 3957/H3957-I 15
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-A-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.
In addition, any compounds capable of forming complexes with
alkaline earth metal ions may be used as co-builders.
In one preferred embodiment of the invention, the tablets are water
softening tablets. Water softening tablets have a very high percentage
content of builders. 60 to 100% by weight of preferred water softening
tablets and, in particularly advantageous embodiments, even as much as
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H 3957/H3957-I 16
80% by weight consist of builders and co-builders. Although active
substance contents of more than 90% by weight and, in particular, more
than 95% by weight are also preferred in these builder tablets, they are
difficult to achieve because water is also introduced into the tablets by the
individual ingredients.
Water softening tablets containing the carbonatelpolycarboxylic acid
system described in the foregoing are particularly preferred. Water
softening systems such as these react effervescently with one another on
contact with water and thus contribute towards the disintegration of the
tablets, soften the water and, in addition, dissolve completely. The
carbonate used may be any alkali metal carbonate, bicarbonate or sesqui-
carbonate either on its own or in the form of mixtures with others.
However, it is particularly preferred to use bicarbonates and sesquicarbon-
ates. Polycarboxylic acids in this context are understood to be carboxylic
acids which carry 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, aminocar-
boxylic acids, nitrilotriacetic acid (NTA), providing there are no ecological
objections to its use, and mixtures thereof. Citric acid, succinic acid,
glutaric acid, adipic acid, gluconic acid and mixtures thereof are
particularly
preferred. These acids may also be used completely or partly in the form
of their salts. Preferred water softening tablets contain 10 to 40% by
weight and more particularly 15 to 30% by weight of such polycarboxylic
acids or polycarboxylic acid salts and 10 to 50% by weight and, more
particularly, 20 to 45% by weight of alkali metal carbonate, bicarbonate or
sesquicarbonate.
In another embodiment of the invention, the tablets are laundry
detergent tablets.
Laundry detergent tablets may advantageously contain surfactants.
These surfactants belong to the group of anionic, nonionic, zwitterionic and
CA 02302141 2000-03-27
H 39571H3957-I 17
cationic surfactants, anionic surfactants being clearly preferred for
economic reasons and for their performance spectrum.
Suitable anionic surfactants are, for example, those of the sulfonate
and sulfate type. Preferred surfactants of the sulfonate type are, for
example, C9_~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 the alkane sulfonates obtained from C,z_~$ alkanes,
for example by sulfochlorination or sulfoxidation and subsequent hydrolysis
or neutralization. The esters of a-sulfofatty acids (ester sulfonates), for
example the a-sulfonated methyl esters of hydrogenated coconut oil, palm
kernel oil or tallow fatty acids, are also suitable.
Other suitable anionic surfactants are sulfonated fatty acid glycerol
esters. Fatty acid glycerol esters in the context of the present invention are
the monoesters, diesters and triesters and mixtures thereof which are
obtained where production is carried out by esterification of a monoglycerol
with 1 to 3 moles of fatty acid or in the transesterification of triglycerides
with 0.3 to 2 moles of glycerol. Preferred sulfonated fatty acid glycerol
esters are the sulfonation products of saturated fatty acids containing 6 to
22 carbon atoms, for example caproic acid, caprylic acid, capric acid,
myristic acid, lauric acid, palmitic acid, stearic acid or behenic acid.
Preferred alk(en)yl sulfates are the alkali metal salts and, in
particular, the sodium salts of the sulfuric acid semiesters of C,2_~8 fatty
alcohols, for example coconut alcohol, tallow alcohol, lauryl, myristyl, cetyl
or stearyl alcohol, or 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
CA 02302141 2000-03-27
H 3957/H3957-I 18
similar in their degradation behavior to the corresponding compounds
based on oleochemical raw materials. C~2_~s alkyl sulfates and C~2.~5 alkyl
sulfates and also C~4_~5 alkyl sulfates are particularly preferred from the
washing performance point of view. Other suitable anionic surfactants 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~.
The sulfuric acid monoesters of linear or branched C~_2~ alcohols
ethoxylated with 1 to 6 moles of ethylene oxide, such as 2-methyl-branched
C9_» alcohols containing on average 3.5 moles of ethylene oxide (EO) or
C,2_,e fatty alcohols containing 1 to 4 EO, are also suitable.
Other suitable anionic surfactants are the salts of alkyl sulfosuccinic
acid which are also known as sulfosuccinates or as sulfosuccinic acid
esters and which represent monoesters and/or diesters of sulfosuccinic
acid with alcohols, preferably fatty alcohols and, more particularly,
ethoxylated fatty alcohols. Preferred sulfosuccinates contain Cg_18 fatty
alcohol residues or mixtures thereof. Particularly preferred sulfosuccinates
contain a fatty alcohol residue derived from ethoxylated fatty alcohols
which, considered in isolation, represent nonionic surfactants (for a
description, see below). Of these sulfosuccinates, those of which the fatty
alcohol residues are derived from narrow-range ethoxylated fatty alcohols
are particularly preferred. Alk(en)yl succinic acid preferably containing 8 to
18 carbon atoms in the alk(en)yl chain or salts thereof may also be used.
Other suitable anionic surfactants are, in particular, soaps. Suitable
soaps are 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 natural fatty
acids, for example coconut oil, palm kernel oil 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
CA 02302141 2000-03-27
H 39571H3957-I 1 g
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.
So far as the choice of anionic surfactants is concerned, there are
no basic requirements to restrict the freedom of formulation. Anionic
surfactants preferably used in detergents are the alkyl benzenesulfonates
and fatty alcohol sulfates, preferred detergent tablets containing 2 to 20%
by weight, preferably 2.5 to 15% by weight and more preferably 5 to 10%
by weight fatty alcohol sulfate(s), based on the weight of the detergent
tablets.
Preferred 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 component may be linear or,
preferably, methyl-branched in the 2-position or may contain linear and
methyl-branched residues in the form of the mixtures typically present in
oxoalcohol residues. However, alcohol ethoxylates containing linear
residues of alcohols of native origin with 12 to 18 carbon atoms, for
example coconut oil, palm oil, 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_» alcohol 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,2_,4 alcohol containing 3 EO and C,Z_~8
alcohol containing 5 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 alcohol containing 14 EO, 25 EO, 30 EO or 40
' CA 02302141 2000-03-27
H 3957/H3957-I 20
EO.
Another class of preferred nonionic surfactants which may be used
either as sole nonionic surfactant or in combination with other nonionic
surfactants 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 58!217598
or which are preferably produced by the process described in International
patent application WO-A-90113533.
Another class of nonionic surfactants which may advantageously be
used are the alkyl polyglycosides (APGs). Suitable alkyl polyglycosides
correspond to the general formula RO(G)Z where R is a linear or branched,
more particularly 2-methyl-branched, saturated or unsaturated 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 glycosidation z is between 1.0 and 4.0, preferably
between 1.0 and 2.0 and more preferably between 1.1 and 1.4.
Linear alkyl polyglucosides, i.e. alkyl polyglycosides in which the
polyglycosyl component is a glucose unit and the alkyl component is an n
alkyl group, are preferably used.
The tablets may advantageously contain alkyl polyglycosides, APG
contents of more than 0.2% by weight, based on the tablet as a whole,
being preferred. Particularly preferred detergent tablets contain APGs in
quantities of 0.2 to 10% by weight, preferably in quantities of 0.2 to 5% by
weight and more preferably in quantities of 0.5 to 3% by weight.
Nonionic surfactants of the amine oxide type, for example N-
coconutalkyl-N,N-dimethylamine oxide and N-tallowalkyl-N,N-dihydroxy-
ethylamine 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
CA 02302141 2000-03-27
H 3957/H3957-I 21
and, more preferably, no more than half that quantity.
Other suitable surfactants are polyhydroxyfatty acid amides
corresponding to formula (I):
R'
R-CO-N-[Z] (I)
in which RCO is an aliphatic acyl group containing 6 to 22 carbon atoms,
R' 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.
The group of polyhydroxyfatty acid amides also includes compounds
corresponding to formula (II):
R'-O-R2
R-C O-N-[Z] ( I I )
in which R is a linear or branched alkyl or alkenyl group containing 7 to 12
carbon atoms, R' is a linear, branched or cyclic alkyl group or an aryl group
containing 2 to 8 carbon atoms and R2 is a linear, branched or cyclic alkyl
group or an aryl group or an oxyalkyl group containing 1 to 8 carbon atoms,
C,~ alkyl or phenyl groups being preferred, and [Z] 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.
[Z] is preferably obtained by reductive amination of a reduced sugar,
for example glucose, fructose, maltose, lactose, galactose, mannose or
i
' CA 02302141 2000-03-27
H 3957/H3957-I 22
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-A-95!07331.
The surfactant content of detergent tablets is normally between 10
and 40% by weight, preferably between 12.5 and 30% by weight and more
preferably between 15 and 25% by weight. Bleach tablets and water
softening tablets are normally free free from surfactants.
Besides the builder constituents and surfactants mentioned, the
tablets according to the invention may also contain one or more substances
from the groups of bleaching agents, bleach activators, enzymes, pH
regulators, perfumes, perfume carriers, fluorescers, dyes, foam inhibitors,
silicone oils, redeposition inhibitors, optical brighteners, discoloration
ihibitors and dye transfer inhibitors. These substances are described in the
following.
Among the compounds yielding H202 in water which serve as
bleaching agents, sodium perborate tetrahydrate, sodium perborate
monohydrate and sodium carbonate 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. Even where the bleaching agents are used,
there is no need for surfactants andlor builders so that pure bleach tablets
can be produced. If pure bleach tablets are to be used in the washing of
laundry, a combination of sodium percarbonate and sodium sesqui-
carbonate is preferred irrespective of the other ingredients present in the
tablets. In principle, bleaching agents from the group of organic bleaches
may also be used. Typical organic bleaching agents are diacyl peroxides,
such as dibenzoyl peroxide for example. Other typical organic bleaching
' CA 02302141 2000-03-27
H 39571H3957-I 23
agents are the peroxy acids, of which alkyl peroxy acids and aryl peroxy
acids are particularly mentioned as examples. Preferred representatives
are (a) peroxybenzoic acid and ring-substituted derivatives thereof, such as
alkyl peroxybenzoic acids, but also peroxy-a-naphthoic acid and
magnesium monoperphthalate, (b) aliphatic or substituted aliphatic peroxy
acids, such as peroxylauric acid, peroxystearic acid, s-
phthalimidoperoxycaproic acid [phthaloiminoperoxyhexanoic acid (PAP)],
o-carboxybenzamidoperoxycaproic acid, N-nonenylamidoperadipic acid
and N-nonenylamidopersuccinates, and (c) aliphatic and araliphatic
peroxydicarboxylic acids, such as 1,12-diperoxycarboxylic acid, 1,9-
diperoxyazelaic acid, diperoxysebacic acid, diperoxybrassylic acid,
diperoxyphthalic acids, 2-decyldiperoxybutane-1,4-dioic acid, N,N-
terephthaloyl-di(6-aminopercaproic acid).
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 tablets according to the invention. The bleach
activators may be compounds which form aliphatic peroxocarboxylic acids
containing preferably 1 to 10 carbon atoms and more preferably 2 to 4
carbon atoms andlor optionally substituted perbenzoic acid under
perhydrolysis conditions. Substances bearing O- and/or N-acyl groups with
the number of carbon atoms mentioned and/or optionally substituted
benzoyl groups are suitable. Preferred bleach activators are polyacylated
alkylenediamines, more particularly tetraacetyl ethylenediamine (TAED),
acylated triazine derivatives, more particularly 1,5-diacetyl-2,4-dioxohexa-
hydro-1,3,5-triazine (DADHT), acylated glycolurils, more particularly tetra-
acetyl glycoluril (TAGU), N-acylimides, more particularly N-nonanoyl
succinimide (NOSI), acylated phenol sulfonates, more particularly n-
nonanoyl or isononanoyloxybenzenesulfonate (n- or iso-NOBS), carboxylic
anhydrides, more particularly phthalic anhydride, acylated polyhydric
alcohols, more particularly triacetin, ethylene glycol diacetate and 2,5-
CA 02302141 2000-03-27
H 3957/H3957-I 24
diacetoxy-2,5-dihydrofuran.
In addition to or instead of the conventional bleach activators
mentioned above, so-called bleach catalysts may also be incorporated in
the tablets. Bleach catalysts are bleach-boosting transition metal salts or
transition metal complexes such as, for example, manganese-, iron-,
cobalt-, ruthenium- or molybdenum-salen complexes or carbonyl
complexes. Manganese, iron, cobalt, ruthenium, molybdenum, titanium,
vanadium and copper complexes with nitrogen-containing tripod ligands
and cobalt-, iron-, copper- and ruthenium-ammine complexes may also be
used as bleach catalysts.
Suitable enzymes are those from the class of proteases, lipases,
amylases, cellulases or mixtures thereof. Enzymes obtained from bacterial
strains or fungi, such as Bacillus subtilis, Bacillus licheniformis and
Streptomyces griseus, are particularly suitable. Proteases of the subtilisin
type are preferred, proteases obtained from Bacillus lentus being
particularly preferred. Enzyme mixtures, for example of protease and
amylase or protease and lipase or protease and cellulase or of cellulase
and lipase or of protease, amylase and lipase or of protease, lipase and
cellulase, but especially cellulase-containing mixtures, are of particular
interest. Peroxidases or oxidases have also proved to be suitable in some
cases. The enzymes may be adsorbed to supports and/or encapsulated in
shell-forming substances to protect them against premature decomposition.
The percentage content of the enzymes, enzyme mixtures or enzyme
granules in the tablets according to the invention may be, for example, from
about 0.1 to 5% by weight and is preferably from 0.1 to about 2% by
weight. The most commonly used enzymes include lipases, amylases,
cellulases and proteases. Preferred proteases are, for example,
BLAP~140 (Biozym), Optimase~ M-400 and Opticlean~ M-250 (Solvay
Enzymes); Maxacal~ CX and Maxapem~ or Esperase~ (Gist Brocades) or
even Savinase~ (Novo). Particularly suitable cellulases and lipases are
CA 02302141 2000-03-27
H 39571H3957-I 25
Celluzym~ 0, T and Lipolase~ 30 T (Novo Nordisk). The amylases
particularly used are Duramyl~ and Termamyl~ 60 T and Termamyl~ 90 T
(novo), Amylase-LT~ (Solvay Enzymes) abd Maxamyl~ P5000 (Gist
Brocades). Other enzymes may also be used.
The tablets may contain derivatives of diaminostilbenedisulfonic 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
composition which contain a diethanolamino group, a methylamino group,
an anilino group or a 2-methoxyethylamino group instead of the morpholino
group. Brighteners of the substituted diphenyl styryl type, for example
alkali metal salts of 4,4'-bis-(2-sulfostyryl)-diphenyl, 4,4'-bis-(4-chloro-3
sulfostyryl)-diphenyl or 4-(4-chlorostyryl)-4'-(2-sulfostyryl)-Biphenyl, may
also be present. Mixtures of the brighteners mentioned above may also be
used.
Dyes and perfumes are added to the detergent tablets according to
the invention to improve the aesthetic impression created by the products
and to provide the consumer not only with the required washing
performance but also with a visually and sensorially "typical and
unmistakable" product. Suitable perfume oils or perfumes include
individual perfume compounds, for example synthetic products of the ester,
ether, aldehyde, ketone, alcohol and hydrocarbon type. Perfume
compounds of the ester type are, for example, benzyl acetate,
phenoxyethyl isobutyrate, p-tert.butyl cyclohexyl acetate, linalyl acetate,
dimethyl benzyl carbinyl acetate, phenyl ethyl acetate, linalyl benzoate,
benzyl formate, ethyl methyl phenyl glycinate, allyl cyclohexyl propionate,
styrallyl propionate and benzyl salicylate. The ethers include, for example,
benzyl ethyl ether; the aldehydes include, for example, the linear alkanals
containing 8 to 18 carbon atoms, citral, citronellal, citronellyloxy-
acetaldehyde, cyclamen aldehyde, hydroxycitronellal, lilial and bourgeonal;
CA 02302141 2000-03-27
H 39571H3957-I 26
the ketones include, for example, the ionones, a-isomethyl ionone and
methyl cedryl ketone; the alcohols include anethol, citronellol, eugenol,
geraniol, linalool, phenyl ethyl alcohol and terpineol and the hydrocarbons
include, above all, the terpenes, such as limonene and pinene. However,
mixtures of various perfumes which together produce an attractive perfume
note are preferably used. Perfume oils such as these may also contain
natural perfume mixtures obtainable from vegetable sources, for example
pine, citrus, jasmine, patchouli, rose or ylang-ylang oil. Also suitable are
clary oil, camomile oil, clove oil, melissa oil, mint oil, cinnamon leaf oil,
lime
blossom oil, juniper berry oil, vetiver oil, olibanum oil, galbanum oil and
labdanum oil and orange blossom oil, neroli oil, orange peel oil and
sandalwood oil.
The detergent tablets according to the invention normally contain
less than 0.01 % by weight of dyes whereas perfumes/fragrances can make
up as much as 2% by weight of the formulation as a whole.
The perfumes may be directly incorporated in the detergents
according to the invention, although it can also be of advantage to apply
the perfumes to supports which strengthen the adherence of the perfume
to the washing and which provide the textiles with a long-lasting fragrance
through a slower release of the perfume. Suitable support materials are,
for example, cyclodextrins, the cyclodextrinlperfume complexes optionally
being coated with other auxiliaries.
In order to improve their aesthetic impression, the detergents
according to the invention may be colored with suitable dyes. Preferred
dyes, which are not difficult for the expert to choose, have high stability in
storage, are not affected by the other ingredients of the detergents or by
light and do not have any pronounced substantivity for textile fibers so as
not to color them.
The present invention also relates to a process for the production of
tablets containing builders and optionally other ingredients of detergents or
CA 02302141 2000-03-27
H 39571H3957-I 27
phases of such tablets, characterized in that a powder-form or granular
additive containing a crystalline layer silicate corresponding to general
formula (I):
NaMSix02x+~ ~ yH24 (I)
in which M is sodium or hydrogen, x is a number of 1.9 to 2.2 and y is a
number of 0 to 33, and (co)polymeric polycarboxylic . acid as its key
constituents is mixed with other builders and optionally ingredients of
detergents to form a premix and the resulting premix is tabletted without the
incorporation of additional disintegrators without a builder effect and with
at
most 2% by weight of tabletting aids to form tablets or phases of tablets.
The builder additive is the additive described in the foregoing. Since
the production process described here is intended to provide the tablets or
phases of tablets described in the foregoing, it is self evident that the
preferred embodiments described in reference to the tablets are also
preferably produced accordingly in the process.
As mentioned in the foregoing, the tablets according to the invention
contain the builder additives according to the invention in varying amounts
according to the application envisaged. In complete analogy, processes
according to the invention in which the builder additive is used in quantities
of 20 to 60% by weight, preferably in quantities of 25 to 55% by weight and
more preferably in quantities of up to 45% by weight are also preferred.
Even the premixes containing the described builder additive have
advantages. These premixes show very good flow properties, so that the
filling shoe can be uniformly filled, and hence help in guaranteeing a
uniform tablet quality. In addition, the premix does not form lumps and,
accordingly, does not cake on the walls of the tablet press. In addition, the
builder additive according to the invention enables the premix to be
tabletted at moderate pressures. This preserves the tabletting tools and
CA 02302141 2000-03-27
H 39571H3957-I 2g
thus increases their useful life.
Depending on the application envisaged, the builder additive is
mixed with other detergent ingredients and the resulting premix is tabletted.
Preferred processes according to the invention are characterized in that the
builder additive is mixed with at least one oxygen bleaching agent selected
from the group of alkali metal perborates, alkali metal percarbonates,
organic peracids and hydrogen peroxide. The bleaching agents in question
were described in the foregoing.
The bleaching performance of bleach-containing tablets, such as
water softening tablets, laundry detergent tablets and bleach tablets, is
preferably boosted by the use of bleach activators. Thus, preferred
processes according to the invention are characterized in that the builder
additive is mixed with at least one bleach activator, preferably from the
group of polyacylated alkylenediamines, more particularly tetraacetyl
ethylenediamine (TAED), N-acyl imides, more particularly N-nonanoyl
succinimide (NOSI), acylated phenol sulfonates, more particularly n-
nonanoyl or isononanoyloxybenzenesulfonate (n- or iso-NOBS), n-methyl
morpholinium acetonitrile methyl sulfate (MMA) and/or the bleach-boosting
transition metal complexes, more particularly containing the central atoms
Mn, Fe, Co, Cu, Mo, V, Ti andlor Ru, preferably from the group of
manganese andlor cobalt salts and/or complexes, more preferably the
cobalt (ammine) complexes, cobalt (acetate) complexes, cobalt (carbonyl)
complexes, chlorides of cobalt or manganese andlor manganese sulfate.
As mentioned in the foregoing, the tablets or phases of tablets
according to the invention may contain other ingredients of detergents so
that preferred variants of the process are carried out accordingly.
In one particularly preferred embodiment, the premix additionally
contains one or more substances from the group of enzymes, pH
regulators, perfumes, perfume carriers, fluorescers, dyes, foam inhibitors,
silicone oils, redeposition inhibitors, optical brighteners, discoloration
CA 02302141 2000-03-27
r
H 3957IH3957-I 2g
inhibitors and dye transfer inhibitors.
Before the particulate premix is compressed to form tablets, it may
be "powdered" with fine-particle surface treatment materials. This can be
of advantage to the quality and physical properties of both the premix
(storage, tabletting) and the final tablets. Fine-particle powdering materials
have been known for some time in the art, zeolites, silicates and other
inorganic salts generally being used. However, the compound is preferably
"powdered" with fine-particle zeolite, zeolites of the faujasite type being
preferred. In the context of the present invention, the expression "zeolite of
the faujasite type" encompasses all three zeolites which form the faujasite
subgroup of zeolite structural group 4 (cf. Donald W. Breck: "Zeolite
Molecular Sieves", John Wiley & Sons, New York, London, Sydney,
Toronto, 1974, page 92). Besides zeolite X, therefore, zeolite Y and
faujasite and mixtures of these compounds may also be used, pure zeolite
X being preferred. Mixtures of the co-crystallizates of zeolites of the
faujasite type with other zeolites which do not necessarily have to belong to
zeolite structure group 4 may also be used for powdering, at least 50% by
weight of the powdering material advantageously consisting of a zeolite of
the faujasite type.
The tablets according to the invention are produced by first dry-
mixing the ingredients, which may be completely or partly pregranulated,
and then tabletting the resulting premix using conventional processes. To
produce the tablets according to the invention, the premix is compacted
between two punches in a die to form a solid compactate. This process,
which is referred to in short hereinafter as tabletting, comprises four
phases, namely metering, compacting (elastic deformation), plastic
deformation and ejection.
The premix is first introduced into the die, the filling level and hence
the weight and shape of the tablet formed being determined by the position
of the lower punch and the shape of the die. Uniform dosing/metering,
i
CA 02302141 2000-03-27
s
H 3957/H3957-I 30
even at high tablet throughputs, is preferably achieved by volumetric
metering of the premix. As the tabletting process continues, the top punch
comes into contact with the premix and continues descending towards the
bottom punch. During this compaction phase, the particles of the premix
are pressed closer together, the void volume in the filling between the
punches continuously diminishing. The plastic deformation phase in which
the particles coalesce and form the tablet begins from a certain position of
the top punch (and hence from a certain pressure on the premix).
Depending on the physical properties of the premix, its constituent particles
are also partly crushed, the premix sintering at even higher pressures. As
the tabletting rate increases, i.e. at high throughputs, the elastic
deformation phase becomes increasingly shorter so that the tablets formed
can have more or less large voids. In the final step of the tabletting
process, the tablet is forced from the die by the bottom punch and carried
away by following conveyors. At this stage, only the weight of the tablet is
definitively established because the tablets can still change shape and size
as a result of physical processes (re-elongation, crystallographic effects,
cooling, etc.).
The tabletting process is carried out in commercially available tablet
presses which, in principle, may be equipped with single or double
punches. In the latter case, not only is the top punch used to build up
pressure, the bottom punch also moves towards the top punch during the
tabletting process while the top punch presses downwards. For small
production volumes, it is preferred to use eccentric tablet presses in which
the punches) islare fixed to an eccentric disc which, in turn, is mounted on
a shaft rotating at a certain speed. The movement of these punches is
comparable with the operation of a conventional four-stroke engine.
Tabletting can be carried out with a top punch and a bottom punch,
although several punches can also be fixed to a single eccentric disc, in
which case 'the number of die bores is correspondingly increased. The
CA 02302141 2000-03-27
H 39571H3957-I 31
throughputs of eccentric presses vary according to type from a few hundred
to at most 3,000 tablets per hour.
For larger throughputs, rotary tablet presses are generally used. In
rotary tablet presses, a relatively large number of dies is arranged in a
circle on a so-called die table. The number of dies varies - according to
model - between 6 and 55, although even larger dies are commercially
available. Top and bottom punches are associated with each die on the
die table, the tabletting pressures again being actively built up not only by
the top punch or bottom punch, but also by both punches. The die table
and the punches move about a common vertical axis, the punches being
brought into the filling, compaction, plastic deformation and ejection
positions by means of curved guide rails. At those places where the
punches have to be raised or lowered to a particularly significant extent
(filling, compaction, ejection), these curved guide rails are supported by
additional push-down members, pull-down rails and ejection paths. The die
is filled from a rigidly arranged feed unit, the so-called filling shoe, which
is
connected to a storage container for the compound. The pressure applied
to the premix can be individually adjusted through the tools for the top and
bottom punches, pressure being built up by the rolling of the punch shank
heads past adjustable pressure rollers.
To increase throughput, rotary presses can also be equipped with
two filling shoes so that only half a circle has to be negotiated to produce a
tablet. To produce two-layer or multiple-layer tablets, several filling shoes
are arranged one behind the other without the lightly compacted first layer
being ejected before further filling. Given suitable process control, shell
and bull's-eye tablets - which have a structure resembling an onion skin -
can also be produced in this way. In the case of bull's-eye tablets, the
upper surface of the core or rather the core layers is not covered and thus
remains visible. Rotary tablet presses can also be equipped with single or
multiple punches so that, for example, an outer circle with 50 bores and an
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inner circle with 35 bores can be simultaneously used for tabletting.
Modern rotary tablet presses have throughputs of more than one million
tablets per hour.
Tabletting machines suitable for the purposes of the invention can
be obtained, for example, from the following companies: Apparatebau
Holzwarth GbR, Asperg, Wilhelm Fette GmbH, Schwarzenbek, Hofer
GmbH, Weil, KILIAN, Cologne, KOMAGE, Kell am See, KORSCH Pressen
GmbH, Berlin, Mapag Maschinenbau AG, Bern (Switzerland) and Courtoy
N.V., Halle (BEILU). One example of a particularly suitable tabletting
machine is the model HPF 630 hydraulic double-pressure press
manufactured by LAEIS, D.
The tablets can be made in certain shapes and certain sizes.
Suitable shapes are virtually any easy-to-handle shapes, for example
slabs, bars, cubes, squares and corresponding shapes with flat sides and,
in particular, cylindrical forms of circular or oval cross-section. This last
embodiment encompasses shapes from tablets to compact cylinders with a
height-to-diameter ratio of more than 1.
The portioned pressings may be formed as separate individual
elements which correspond to a predetermined dose of the detergent.
However, it is also possible to form pressings which combine several such
units in a single pressing, smaller portioned units being easy to break off in
particular through the provision of predetermined weak spots. For the use
of laundry detergents in machines of the standard European type with
horizontally arranged mechanics, it can be of advantage to produce the
portioned pressings as cylindrical or square tablets, preferably with a
diameter-to-height ratio of about 0.5:2 to 2:0.5. Commercially available
hydraulic presses, eccentric presses and rotary presses are particularly
suitable for the production of pressings such as these.
The three-dimensional form of another embodiment of the tablets
according to the invention is adapted in its dimensions to the dispensing
w CA 02302141 2000-03-27
H 3957/H3957-I 33
compartment of commercially available domestic washing machines, so
that the tablets can be introduced directly, i.e. without a dosing aid, into
the
dispensing compartment where they dissolve on contact with water.
However, it is of course readily possible - and preferred in accordance with
the present invention - to use the water softening and laundry detergent
tablets in conjunction with a dosing aid.
Another preferred tablet which can be produced has a plate-like or
slab-like structure with alternately thick long segments and thin short
segments, so that individual segments can be broken off from this "bar" at
the predetermined weak spots, which the short thin segments represent,
and introduced into the machine. This "bar" principle can also be
embodied in other geometric forms, for example vertical triangles which are
only joined to one another at one of their longitudinal sides.
In another possible embodiment, however, the various components
are not compressed to form a single tablet, instead the tablets obtained
comprise several layers or "phases", i.e. at least two layers. These various
layers may have different dissolving rates. This may advantageously be
achieved in particular if only one of the layers contains the builder additive
acording to the invention while the other layer contains no disintegrator at
all or another disintegrator. This can provide the tablets with favorable
performance properties. If, for example, the tablets contain components
which adversely affect one another, one component may be integrated in
the more quickly dissolving layer while the other component may be
incorporated in a more slowly dissolving layer so that the first component
can already have reacted off by the time the second component dissolves.
The various layers of the tablets can be arranged in the form of a stack, in
which case the inner layers) dissolve at the edges of the tablet before the
outer layers have completely dissolved. Alternatively, however, the inner
layers) may also be completely surrounded by the layers lying further to
the outside which prevents constituents of the inner layers) from dissolving
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prematurely.
In another preferred embodiment of the invention, a tablet consists
of at least three layers, i.e. two outer layers and at least one inner layer,
a
peroxy bleaching agent being present in at least one of the inner layers
whereas, in the case of the stack-like tablet, the two cover layers and, in
the case of the envelope-like tablet, the outermost layers are free from
peroxy bleaching agent. In another possible embodiment, peroxy bleach-
ing agent and any bleach activators present and/or enzymes may be
spatially separated from one another in one and the same tablet. Multilayer
tablets such as these have the advantage that they can be used not only
via a dispensing compartment or via a dosing unit which is added to the
wash liquor, instead it is also possible in cases such as these to introduce
the tablet into the machine in direct contact with the fabrics without any
danger of spotting by bleaching agent or the like.
Similar effects can also be obtained by coating individual
constituents of the detergent composition to be compressed or the tablet as
a whole. To this end, the tablets to be coated may be sprayed, for
example, with aqueous solutions or emulsions or a coating may be
obtained by the process known as melt coating.
After pressing, the detergent tablets have high stability. The fracture
resistance of cylindrical tablets can be determined via the diametral fracture
stress. This in turn can be determined in accordance with the following
equation:
2P
a =
nDt
where n represents the diametral fracture stress (DFS) in Pa, P is the force
in N which leads to the pressure applied to the tablet that results in
fracture
thereof, D is the diameter of the tablet in meters and t is its height.
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Examples
Water softening tablets were produced from the ingredients listed in
Table 1 in a rotary press (manufacturer: Fette). To this end, the individual
components were mixed and the resulting premix was tabletted under the
pressure shown in Table 2. All the tablets had a weight of 18 g. The
tabletting pressure was selected so that all the tablets had the same height.
A layer silicate/polymer compound was used in Examples E1 to E3
according to the invention. This compound had been formed by reacting
SKS-6~ (Clariant) with a terpolymer according to patent application EP-A-
849 355. The terpolymer used had been produced in accordance with the
disclosure of WO 94!15978 from 80% by weight of acrylic acid and malefic
acid in a ratio by weight of 7:3 and 20% by weight of vinyl acetate and then
saponified in an acidic medium (commercial product of Stockhausen). The
resulting builder additive contained 71 % by weight of SKS-6, 20% by
weight of the terpolymer and 9% by weight of water. Copolymer - an
acrylic acid/maleic acid copolymer (Sokalan CP5~, a product of BASF) -
was used in Example E2 and in the Comparison Examples. Comparison
Examples C1 and C3 contained layer silicate in the form of SKS-6 powder.
The Comparison Examples also contained microcrystalline cellulose as a
disintegrator and a polyethylene glycol with a molecular weight of 4000
g/mole as a tabletting aid. In exactly the same way as the polyethylene
glycol used in the Comparison Examples (molecular weight 400 glmole),
the paraffin oil used in the Examples according to the invention serves as a
dust binding agent. Balances to 100% by weight in Table 1 are made up
by water additionally present and salts.
The Examples according to the invention gave harder tablets with
greater edge breakage stability than the Comparison Examples, despite
lower tabletting pressures. At the same time, the tablets according to the
invention have comparable dissolving times to the Comparison Examples.
Less caking on the walls of the filling shoes and in the die were also
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observed in the production of the tablets according to the invention (see
Table 2).
Table 1:
Composition of the tablets [% by weight]
E1 E2 E3 C1 C2 C3
Citric acid 21 26 28 21 16 14
Bicarbonate 30 34 42 30 25 20
Citrate - - - - - 35
Sodium perborate monohydrate4 - _ _ _ _
Paraffin oil 1 1 1 - - _
PEG 400 - - - 1 1 1
PEG 4000 - - - 3 5 4
Microcrystalline cellulose - - - 6 7 7
Zeolite - - - - 30 -
Copolymer - 5 - 9 8 14
Layer silicate (powder) - _ _ 3p _ 5
Layer silicate/polymer compound44 34 29 - - _
The hardness of the tablets was measured by deforming a tablet
until it broke, the force being applied to the sides of the tablet and the
maximum force withstood by the tablet being determined. The measure-
ment was carried out in a Holland CT5 hardness tester with punch
diameters of 8 mm.
The edge breakage test was carried out in a rectangular plastic
container with edge lengths of 18 x 14 x 22 cm. Five tablets were weighed
into this container which was then rotated for 1 minute at 40 r.p.m. The
tablets were then reweighed, the result being expressed as the weight of
the tablets after the test as a percentage of the weight of the tablets before
the test (Table 2).
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The dissolving test was carried out in a glass beaker at 20°C. To
this end, a 14.8 x 34.4 mm tablet was placed on a sieve with a mesh width
of 0.6 x 0.6 cm, after which the sieve was suspended in a 1000 ml glass
beaker filled with water. The time which the tablet took to drop through the
sieve was measured while stirring.
For the dissolving test in a washing machine, three tablets were
placed in the drum of a washing machine filled with laundry. The machine
was then switched on (30°C program, no prewash). The time measure-
ment was started when the drum began to rotate. The washing process
was then terminated and the water pumped off after 1, 2, 3, 4 and 5
minutes. The time after which no tablet residues were found was then
determined as the dissolving time. The values listed in Table 2 are mean
values of double determinations.
Caking on the tablet press was visually evaluated. Evaluation is
based on the following code: very good (++); no significant caking; good
(+): visible caking, but no adverse effect on tabletting; satisfactory (0):
visible caking, slight interference with tabletting; poor (-): serious
interfer-
ence with tabletting.
The experimental data of the individual tablet series are shown in
Table 2:
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H 39571H3957-I 3g
Table 2:
Properties of the tablets
E1 E2 E3 C1 C2 C3
Tabletting pressure (kN] 32 ~ 46 56 70 _ 74
68
Tablet hardness (kg] 12 ~ 11 12 9 8 6
Edge breakage test (%] 94 92 91 84 86 82
Dissolving time (mina.]
- in a glass beaker 1.3 1.0 0.8 0.8 2.5 0.7
- in a washing machine 1.5 1.5 1.5 1.5 3.5 1.5
Bulk density (gll] 810 810 810 770 680 740
Caking ++ ++ ++ + - +
