Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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DETERGENT TABLETS, ESPECIALLY FOR MACHINE DI
Field of the Invention
The present invention relates to detergent tablets
comprising builders and bleaches. The invention relates
in particular to detergent tablets for machine dish-
washing which are wholly or partly dissolution-
accelerated.
Background of the Invention
Detergent tablets have been widely described in the
prior art and are enjoying increasing popularity among
users owing to the ease of dosing. Tableted detergents
have a number of advantages over their powder-form
counterparts: they are easier to dose and to handle,
and have storage and transport advantages owing to
their compact structure. Consequently, detergent
tablets have been described comprehensively in the
patent literature as well. One problem which occurs
again and again in connection with the use of detersive
tablets however, is the inadequate disintegration and
dissolution rate of the tablets under application
conditions. Since tablets of sufficient stability,
i.e., dimensional stability and fracture resistance,
can be produced only by means of relatively high
compression pressures, there is severe compaction of
the tablet constituents and, consequently, retarded
disintegration of the tablet in the aqueous liquor,
leading to excessively slow release of the active
substances in the cleaning operation.
In the field of detergents it is possible inter alia,
in accordance with the teaching of European patent EP-
B-0 523 099, to use the disintegrants known from drug
manufacture. Disintegrants mentioned include swellable
phyllosilicates such as bentonites, natural substances
and natural substance derivatives based on starch and
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on cellulose, alginates and the like, potato starch,
methylcellulose and/or hydroxypropylcellulose. These
disintegrants may either be mixed with the granules for
compression or else incorporated into the granules for
compression.
International Patent Application WO-A-96/06156 likewise
indicates that the incorporation of disintegrants into
detergent tablets may be of advantage. Here again,
typical disintegrants specified include micro-
crystalline cellulose, sugars such as sorbitol, and
phyllosilicates, especially finely divided and
swellable phyllosilicates of the bentonite and smectite
type. Substances which contribute to the formation of
gas, such as citric acid, bisulfate, bicarbonate,
carbonate and percarbonate, are also cited as possible
disintegration aids.
According to EP-A-0 711 827, the use of particles
consisting predominantly of citrate, which has a
certain solubility in water, has the secondary
consequence also of an accelerated disintegration of
the tablets. It is hypothesized that the dissolution of
the citrate brings about a local increase in the ionic
strength during a transition period, thereby
suppressing the gelling of surfactants, as a
consequence of which the disintegration of the tablet
is not hindered. According to this patent application,
therefore, citrate is not a conventional disintegrant
but acts, instead, as an antigelling agent.
Detergent tablets comprising cellulose-based
disintegrants in granular or optionally cogranulated
form are described in German Patent Applications DE
197 09 991 (Stefan Herzog) and DE 197 10 254 (Henkel)
and in International Patent Applications VJ098/40462
(Stefan Herzog) and ~n1O98/40463 (Henkel). These
documents also contain details on the production of
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granulated, compacted or cogranulated cellulose
disintegrants.
In the production of drug tablets, the abovementioned
proposed solutions lead to the desired success . In the
detergent field, although they do contribute to
improving the disintegration properties of tablets with
a washing or cleaning activity, the improvement
achieved is in many cases inadequate. Additionally, the
use of the proposed disintegration aids in detersive
tablets for machine dishwashing may lead to specific
properties which are completely unknown to drugs or
laundry detergents.
Sumanary of the Invention
It is an object of the invention to provide a
disintegration aid for detersive tablets which on the
one hand shorten the disintegration time of the tablet,
or parts of the tablet, in standard domestic
dishwashing machines, but on the other hand is easy to
incorporate into the mixtures for compression without
losing its active form. Relative to the disintegrants
described in the prior art, the activity should not be
restricted only to the disintegration effect; instead,
the auxiliary should as far as possible take over
further functions in the cleaning process.
It has now been found that addition of small amounts of
finely divided, preferably essentially water-insoluble
auxiliaries, especially zeolite, to phosphate-
containing detergent tablets accelerates the solubility
of individual phases or of the entire tablet.
The invention provides detergent tablets comprising
builders and bleaches and, optionally, further
customary detergent ingredients and having a phosphate
content of from 20 to 95% by weight, said tablets
further comprising from 0.1 to 9% by weight of a finely
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divided auxiliary having an average particle size of
less than 100 Vim.
The finely divided auxiliaries are preferably used in
even finer form, so that in preferred detergent tablets
the finely divided auxiliary has an average particle
size of less than 40 Vim, preferably less than 20 Vim,
and in particular less than 10 Vim.
Detailed Description of the Invention
The particle size distribution of the auxiliary used is
the essential feature for the success of the present
invention, the nature of the auxiliary used playing
only a minor role. However, it has been found that
substances of relatively low solubility in water,
surprisingly, provide better effects, so that the
finely divided auxiliary in preferred detergent tablets
is essentially water-insoluble.
In the context of the present invention, the term
"essentially water-insoluble" characterizes substances
whose solubility in water is negligibly small.
Milligram amounts, at most, of such substances having
negligibly small water solubilities dissolve in one
liter of water.
From the group of the finely divided, preferably water-
insoluble auxiliaries, in addition to pyrogenic
silicas, zeolite in particular has proven particularly
suitable. Particularly preferred detergent tablets of
the invention comprise zeolite as finely divided
auxiliary.
There follows a description of the most important
ingredients of the detergent tablets of the invention.
In machine dishwashing compositions in particular,
phosphates are used as builder substances; however,
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their use is also possible with advantage in laundry
detergents, provided such a use is not to be avoided on
ecological grounds. Among the large number of
commercially available phosphates, the alkali metal
phosphates, with particular preference being given to
pentasodium and pentapotassium triphosphate (sodium and
potassium tripolyphosphate, respectively), possess the
greatest importance in the detergent industry.
Alkali metal phosphates is the collective term for the
alkali metal (especially sodium and potassium) salts of
the various phosphoric acids, among which
metaphosphoric acids (HP03)n and orthophosphoric acid
H3P04, in addition to higher-molecular-mass
representatives, may be distinguished. The phosphates
combine a number of advantages: they act as alkali
carriers, prevent limescale deposits on machine
components, and lime incrustations on fabrics, and
additionally contribute to cleaning performance.
Sodium dihydrogen phosphate, NaH2P04, exists as the
dihydrate (density 1.91 g cm-3, melting point 60°) and
as the monohydrate (density 2.04 g cm-3). Both salts are
white powders of very ready solubility in water which
lose the water of crystallization on heating and
undergo conversion at 200°C into the weakly acidic
diphosphate (disodium dihydrogen diphosphate, Na2H2Pz0~)
and at the higher temperature into sodium
trimetaphosphate (Na3P309) and Maddrell's salt (see
below). NaHzP04 reacts acidically; it is formed if
phosphoric acid is adjusted to a pH of 4.5 using sodium
hydroxide solution and the slurry is sprayed. Potassium
dihydrogen phosphate (primary or monobasic potassium
phosphate, potassium biphosphate, PDP), KHzP04, is a
white salt with a density of 2.33 g cm-3, has a melting
point of 253° [decomposition with formation of
potassium polyphosphate (KP03)X], and is readily soluble
in water.
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Disodium hydrogen phosphate (secondary sodium
phosphate), Na2HP04, is a colorless, crystalline salt
which is very readily soluble in water. It exists in
anhydrous form and with 2 mol (density 2.066 g cm-3,
water loss at 95°) , 7 mol (density 1.68 g cm-3, melting
point 48° with loss of 5 H20), and 12 mol of water
(density 1.52 g cm-3, melting point 35° with loss of
5 H20), becomes anhydrous at 100°, and if heated more
severely undergoes transition to the diphosphate
Na4P20~. Disodium hydrogen phosphate is prepared by
neutralizing phosphoric acid with sodium carbonate
solution using phenolphthalein as indicator.
Dipotassium hydrogen phosphate (secondary or dibasic
potassium phosphate), KzHP04, is an amorphous white salt
which is readily soluble in water.
Trisodium phosphate, tertiary sodium phosphate, Na3P04,
exits as colorless crystals which as the dodecahydrate
have a density of 1.62 g cm-3 and a melting point of
73-76°C (decomposition), as the decahydrate
(corresponding to 19-20% P205) have a melting point of
100°C, and in anhydrous form (corresponding to 39-40%
P205) have a density of 2.536 g cm-3. Trisodium
phosphate is readily soluble in water, with an alkaline
reaction, and is prepared by evaporative concentration
of a solution of precisely 1 mol of disodium phosphate
and 1 mol of NaOH. Tripotassium phosphate (tertiary or
tribasic potassium phosphate), K3P04, is a white,
deliquescent, granular powder of density 2.56 g cm-3,
has a melting point of 1340°, and is readily soluble in
water with an alkaline reaction. It is produced, for
example, when Thomas slag is heated with charcoal and
potassium sulfate. Despite the relatively high price,
the more readily soluble and therefore highly active
potassium phosphates are frequently preferred in the
cleaning products industry over the corresponding
sodium compounds.
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Tetrasodium diphosphate (sodium pyrophosphate), Na4P20~,
exists in anhydrous form (density 2.534 g cm-3, melting
point 988°, 880° also reported) and as the decahydrate
(density 1.815-1.836 g cm-3, melting point 94° with loss
of water). Both substances are colorless crystals which
dissolve in water with an alkaline reaction. Na4P20~ is
formed when disodium phosphate is heated at > 200° or
by reacting phosphoric acid with sodium carbonate in
stoichiometric ratio and dewatering the solution by
spraying. The decahydrate complexes heavy metal salts
and water hardeners and therefore reduces the hardness
of the water. Potassium diphosphate (potassium
pyrophosphate) , K4P20~, exists in the form of the
trihydrate and is a colorless, hygroscopic powder of
density 2.33 g cm-3 which is soluble in water, the pH of
the 1% strength solution at 25° being 10.4.
Condensation of NaHzP04 or of KHzP04 gives rise to
higher-molecular-mass sodium and potassium phosphates,
among which it is possible to distinguish cyclic
representatives, the sodium and potassium metaphos-
phates, and catenated types, the sodium and potassium
polyphosphates. For the latter in particular a large
number of names are in use: fused or calcined
phosphates, Graham's salt, Kurrol's and Maddrell's
salt. All higher sodium and potassium phosphates are
referred to collectively as condensed phosphates.
The industrially important pentasodium triphosphate,
Na5P301o (sodium tripolyphosphate) , is a nonhygroscopic,
white, water-soluble salt which is anhydrous or
crystallizes with 6 H20 and has the general formula
Na0- [P (O) (ONa) -O] n-Na where n - 3 . About 17 g of the
anhydrous salt dissolve in 100 g of water at room
temperature, at 60° about 20 g, at 100° around 32 g;
after heating the solution at 100°C for two hours,
about 8% orthophosphate and 15% diphosphate are
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produced by hydrolysis. For the preparation of
pentasodium triphosphate, phosphoric acid is reacted
with sodium carbonate solution or sodium hydroxide
solution in stoichiometric ratio and the solution is
dewatered by spraying. In a similar way to Graham's
salt and sodium diphosphate, pentasodium triphosphate
dissolves numerous insoluble metal compounds (including
lime soaps, etc). Pentapotassium triphosphate, KSP301o
(potassium tripolyphosphate), is commercialized, for
example, in the form of a 50% strength by weight
solution (> 23% Pz05, 25% K20) . The potassium
polyphosphates find broad application in the laundry
detergents and cleaning products industry. There also
exist sodium potassium tripolyphosphates, which may
likewise be used for the purposes of the present
invention. These are formed, for example, when sodium
trimetaphosphate is hydrolyzed with KOH:
(NaP03 ) 3 + 2 KOH ~ Na3K2P301o + H20
They can be used in accordance with the invention in
precisely the same way as sodium tripolyphospate,
potassium tripolyphosphate, or mixtures of these two;
mixtures of sodium tripolyphosphate and sodium
potassium tripolyphosphate, or mixtures of potassium
tripolyphosphate and sodium potassium tripolyphosphate,
or mixtures of sodium tripolyphosphate and potassium
tripolyphosphate and sodium potassium tripolyphospate,
may also be used in accordance with the invention.
The detergent tablets of the invention comprise the
phosphates) in amounts of from 20 to 95% by weight,
based in each case on the tablet. In preferred
detergent tablets, the phosphate content is from 30 to
92.5% by weight, preferably from 40 to 90% by weight,
and in particular from 50 to 85% by weight, based in
each case on the tablet.
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As the second constituent from the group of the
builders, the detergent tablets of the invention, in
particularly preferred embodiments, comprise zeolite.
The use of zeolite in the stated amounts and with the
stated particle size distribution leads to an
accelerated dissolution of the tablet, and/or of the
phases of the tablet having the stated composition. The
finely crystalline, synthetic zeolite used, containing
bound water, is preferably zeolite A and/or X, Y and/or
P. A particularly preferred zeolite P is Zeolite MAP~
(commercial product from Crosfield). A product
available commercially and able to be used with
preference in the context of the present invention, for
example, is a cocrystallizate of zeolite X and zeolite
A (approximately 80% by weight zeolite X), which is
sold by CONDEA Augusta S.p.A. under the brand name
VEGOBOND AX~ and may be described by the formula
nNa20~ (1-n) KZO~A1203~ (2-2. 5) Si02~ (3 . 5-5. 5) H20.
These amounts are based on the water-free, i.e.,
unhydrated granular compound or as a kind of
"powdering" for the zeolite. Suitable zeolites contain
preferably from 18 to 22% by weight, in particular from
20 to 22% by weight, of bound water.
Zeolite has the general formula M2/nO~A1203~xSiOz~yH20,
where M is a cation of valence n, x is greater than or
equal to 2, and y may adopt values between 0 and 20.
The zeolite structures are formed by the linkage of
A104 tetrahedra to Si04 tetrahedra, this network being
occupied by cations and water molecules. The cations in
these structures are relatively mobile and may, to
differing extents, be replaced by other cations. The
intercrystalline "zeolitic" water may, depending on
zeolite type, be given off continuously and reversibly,
while with certain zeolite types there are structural
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changes associated with the release and acceptance,
respectively, of water.
Within the structural subunits, the "primary bonding
units" (A104 tetrahedra and Si04 tetrahedra) form so-
called "secondary binding units", which possess the
form of single or multiple rings. Thus in different
zeolites, for example, 4-, 6- and 8-membered rings
occur (designated S4R, S6R and S8R), while other types
are connected by four- and six-membered double ring
prisms (the most frequent types are D4R as a tetragonal
and D6R as a hexagonal prism). These "secondary sub-
units" link different polyhedra which are designated
using Greek letters. The most widespread of these is a
polyhedron composed of six squares and eight equal-
sided hexagons, which is referred to as "(3". Using
these building units it is possible to realize
multivarious different zeolites. At the present time,
34 natural zeolite minerals and approximately 100
synthetic zeolites are known.
The best-known zeolite, zeolite 4 A, is a cubic
composite of (3 cages linked by D4R subunits. It belongs
to zeolite structural group 3 and its three-dimensional
network has pores of 2.2 A and 4.2 A in size; the
formula unit within the unit cell can be described as
Nalz [ (AlOz ) iz ( S iOz ) iz ] ~ 2 7 H20 .
In accordance with the invention it is preferred to use
zeolites of the faujasite type. Together with zeolites
X and Y, the mineral faujasite is one of the faujasite
types within zeolite structural group 4, which is
characterized by the double six-membered ring subunit
D6R (cf. Donald W. Breck: "Zeolite Molecular Sieves",
John Wiley & Sons, New York, London, Sydney, Toronto,
1974, page 92). In addition to said faujasite types,
zeolite structural group 4 includes the mineral
chabazite and gmelinite and also the synthetic zeolites
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R (chabazite type), S (gmelinite type), L, and ZK-5.
The two last-mentioned synthetic zeolites have no
mineral analog.
Zeolites of the faujasite type are composed of [3 cages
linked tetrahedrally via D6R subunits, the (3 cages
being arranged similarly to the carbon atoms in a
diamond. The three-dimensional network of the
faujasite-type zeolites used in the process of the
invention have pores of 2.2 and 7.4 A type; the unit
cell further contains 8 cavities of approximately 13 A
in diameter and may be described by the formula
Naes [ (A102) 8s (SiOz) lost ~ 264 H20. The network of zeolite X
contains a cavity volume of approximately 50%, based on
the dehydrated crystal, which represents the greatest
empty space of all known zeolites (zeolite Y: approx.
48% cavity volume; faujasite: approx. 47% cavity
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 term
"faujasite-type zeolite" characterizes all three
zeolites which form the faujasite subgroup of zeolite
structural group 4. In accordance with the invention,
therefore, not only zeolite X but also zeolite Y and
faujasite, and mixtures of these compounds, may be used
preferentially in accordance with the invention,
preference being given to straight zeolite X.
It is also possible in accordance with the invention to
use mixtures or cocrystallizates of faujasite-type
zeolites with other zeolites, which need not
necessarily belong to zeolite structural group 4.
The aluminum silicates used in accordance with the
invention are available commercially and the methods of
preparing them are described in standard monographs.
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Examples of commercially available zeolites of the X
type may be described by the following formulae:
Nae6 L (A102 ) e6 ( S i02 ) los l ' x Hz0
K86 L (A102 ) 86 ( 512 ) 106 ~ ' X H20
Ca4oNa6 [ (A102) as (Si02) los] 'x Ha0
SrzlBa2a LA102) e6 (Si02) los] 'x H20
where x may adopt values between 0 and 276; they have
pore sizes of from 8.0 to 8.4 A.
Zeolites of the Y type are also available commercially
and may be described, for example, by the formulae
Na56 L (A1~2) 56 (Sl~z) 136 'x H2~
Ks6 L (A1~2) 56 (512) 136 'x H2~
where x is a number between 0 and 276, and they have
pore sizes of 8.0 A.
Preferred detergent tablets comprise, based in each
case on the tablet, 0.25 to 7.5% by weight, preferably
from 0.5 to 5% by weight, and in particular from 1 to
3% by weight, of zeolite, preferably zeolite X, Y
and/or P.
In addition to phosphates) and zeolite in the stated
amounts, the detergent tablets of the invention may
comprise further builders, which in some cases may also
serve as alkali carriers. Mention may be made here in
particular of silicates, carbonates, carboxylates,
especially citrates, and polymers, which are described
below.
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Suitable crystalline, layered sodium silicates possess
the general formula NaMSiX02X+1yH20. where M is sodium or
hydrogen, x is a number from 1.9 to 4, y is a number
from 0 to 20, and preferred values for x are 2, 3 or 4.
Crystalline phyllosilicates of this kind are described,
for example, in European Patent Application EP-A-0 164
514. Preferred crystalline phyllosilicates of the
formula indicated are those in which M is sodium and x
adopts the value 2 or 3. In particular, both (3- and
b-sodium disilicates Na2Si205~yH20 are preferred,
(3-sodium disilicate, for example, being obtainable by
the process described in International Patent
Application WO-A-91/08171.
It is also possible to use amorphous sodium silicates
having an Na20:Si02 modulus of from 1:2 to 1:3.3,
preferably from 1:2 to 1:2.8, and in particular from
1:2 to 1:2 .6, which are dissolution-retarded and have
secondary washing properties. The retardation of
dissolution relative to conventional amorphous sodium
silicates
may have
been brought
about in
a variety
of
ways - for example, by surface treatment, compounding,
compacting, or overdrying. In the context of this
invention, the term "amorphous" also embraces "X-ray-
amorphous". This means that in X-ray diffraction
experiments the silicates do not yield the sharp X-ray
reflections typical of crystalline substances but
instead yield
at best one
or more maxima
of the
scattered -radiation, having a width of several degree
X
units of the
diffraction
angle. However,
good builder
properties may result, even particularly good builder
properties, if the silicate particles in electron
diffraction experiments yield vague or even sharp
diffraction maxima. The interpretation of this is that
the product s have microcrystalline regions with a size
of from 10 to several hundred nm, values up to max.
50 nm and in particular up to max. 20 nm being
preferred. So-called X-ray-amorphous silicates of this
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kind, which likewise possess retarded dissolution
relative to the conventional waterglasses, are
described, for example, in German Patent Application
DE-A-44 00 024. Particular preference is given to
compacted amorphous silicates, compounded amorphous
silicates, and overdried X-ray-amorphous silicates.
Particularly suitable carbonates are alkali metal
carbonates and hydrogen carbonates, particular
importance being possessed by the sodium salts and,
among them, by anhydrous sodium carbonate ("calcined
soda"). It is further possible to use sodium carbonate
decahydrate, sodium hydrogen carbonate, potassium
carbonate, potassium carbonate 1.5-water ("potash
hydrate"), potassium hydrogen carbonate, and mixtures
of these.
Organic cobuilders which may be used in the detergent
tablets of the invention are polycarboxylates/
polycarboxylic acids, polymeric polycarboxylates,
aspartic acid, polyacetals, dextrins, further organic
cobuilders (see below), and phosphonates. These classes
of substance are described below.
Organic builder substances which may be used are, for
example, the polycarboxylic acids, usable in the form
of their sodium salts, the term polycarboxylic acids
meaning those carboxylic acids which carry more than
one acid function. Examples of these are citric acid,
adipic acid, succinic acid, glutaric acid, malic acid,
tartaric acid, malefic acid, fumaric acid, sugar acids,
amino carboxylic acids, nitrilotriacetic acid (NTA),
provided such use is not objectionable on ecological
grounds, and also mixtures 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.
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The acids per se may also be used. In addition to their
builder effect, the acids typically also possess the
property of an acidifying component and thus also serve
to establish a lower and milder pH of laundry
detergents or cleaning products. In this context,
mention may be made in particular of citric acid,
succinic acid, glutaric acid, adipic acid, gluconic
acid, and any desired mixtures thereof.
Also suitable as builders are polymeric poly-
carboxylates; these are, for example, the alkali metal
salts of polyacrylic acid or of polymethacrylic acid,
examples being those having a relative molecular mass
of from 500 to 70,000 g/mol.
The molecular masses reported for polymeric poly-
carboxylates, for the purposes of this document, are
weight-average molecular masses, Mw, of the respective
acid form, determined basically by means of gel
permeation chromatography (GPC) using a W detector.
The measurement was made against an external
polyacrylic acid standard, which owing to its
structural similarity to the polymers under
investigation provides realistic molecular weight
values. These figures differ markedly from the
molecular weight values obtained using poly-
styrenesulfonic acids as the standard. The molecular
masses measured against polystyrenesulfonic acids are
generally much higher than the molecular masses
reported in this document.
Suitable polymers are, in particular, polyacrylates,
which preferably have a molecular mass of from 2000 to
20,000 g/mol. Owing to their superior solubility,
preference in this group may be given in turn to the
short-chain polyacrylates, which have molecular masses
of from 2000 to 10,000 g/mol, and with particular
preference from 3000 to 5000 g/mol.
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Also suitable are copolymeric polycarboxylates,
especially those of acrylic acid with methacrylic acid
and of acrylic acid or methacrylic acid with malefic
acid. Copolymers which have been found particularly
suitable are those of acrylic acid with malefic acid
which contain from 50 to 90% by weight acrylic acid and
from 50 to 10% by weight malefic acid. Their relative
molecular mass, based on free acids, is generally from
2000 to 70,000 g/mol, preferably from 20,000 to
50,000 g/mol, and in particular from 30,000 to
40,000 g/mol.
The (co)polymeric polycarboxylates can be used either
as powders or as aqueous solutions. The (co)polymeric
polycarboxylate content of the compositions is
preferably from 0.5 to 20% by weight, in particular
from 3 to 10% by weight.
In order to improve the solubility in water, the
polymers may also include allylsulfonic acids, such as
allyloxybenzenesulfonic acid and methallylsulfonic
acid, for example, as monomers.
Particular preference is also given to biodegradable
polymers comprising more than two different monomer
units, examples being those comprising, as monomers,
salts of acrylic acid and of malefic acid, and also
vinyl alcohol or vinyl alcohol derivatives, or those
comprising, as monomers, salts of acrylic acid and of
2-alkylallylsulfonic acid, and also sugar derivatives.
Further preferred copolymers are those described in
German Patent Applications DE-A-43 03 320 and DE-A-44
17 734, whose monomers are preferably acrolein and
acrylic acid/acrylic acid salts, and, respectively,
acrolein and vinyl acetate.
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Similarly, further preferred builder substances that
may be mentioned include polymeric amino dicarboxylic
acids, their salts or their precursor substances.
Particular preference is given to polyaspartic acids
and their salts and derivatives, which are disclosed in
German Patent Application DE-A-195 40 086 to have not
only cobuilder properties but also a bleach-stabilizing
action.
Further suitable builder substances are polyacetals,
which may be obtained by reacting dialdehydes with
polyol carboxylic acids having 5 to 7 carbon atoms and
at least 3 hydroxyl groups. Preferred polyacetals are
obtained from dialdehydes such as glyoxal,
glutaraldehyde, terephthalaldehyde and mixtures thereof
and from polyol carboxylic acids such as gluconic acid
and/or glucoheptonic acid.
Further suitable organic builder substances are
dextrins, examples being oligomers and polymers of
carbohydrates, which may be obtained by partial
hydrolysis of starches. The hydrolysis can be conducted
by customary processes; for example, acid-catalyzed or
enzyme-catalyzed processes. The hydrolysis products
preferably have average molecular masses in the range
from 400 to 500,000 g/mol. Preference is given here to
a polysaccharide having a dextrose equivalent (DE) in
the range from 0.5 to 40, in particular from 2 to 30,
DE being a common measure of the reducing effect of a
polysaccharide in comparison to dextrose, which
possesses a DE of 100. It is possible to use both
maltodextrins having a DE of between 3 and 20 and dried
glucose syrups having a DE of between 20 and 37, and
also so-called yellow dextrins and white dextrins
having higher molecular masses, in the range from 2000
to 30,000 g/mol.
The oxidized derivatives of such dextrins comprise
their products of reaction with oxidizing agents which
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are able to oxidize at least one alcohol function of
the saccharide ring to the carboxylic acid function.
Oxidized dextrins of this kind, and processes for
preparing them, are known, for example, from European
Patent Applications EP-A-0 232 202, EP-A-0 427 349,
EP-A-0 472 042 and EP-A-0 542 496 and from
International Patent Applications WO 92/18542, WO
93/08251, WO 93/16110, WO 94/28030, WO 95/07303, WO
95/12619 and WO 95/20608. Likewise suitable is an
oxidized oligosaccharide in accordance with German
Patent Application DE-A-196 00 018. A product oxidized
at C6 of the saccharide ring may be particularly
advantageous.
Oxydisuccinates and other derivatives of disuccinates,
preferably ethylenediamine disuccinate, are further
suitable cobuilders. Ethylenediamine N,N'-disuccinate
(EDDS) is used preferably in the form of its sodium or
magnesium salts. Further preference in this context is
given to glycerol disuccinates and glycerol
trisuccinates as well. Suitable use amounts in
formulations containing zeolite and/or silicate are
from 3 to 15% by weight.
Examples of further useful organic cobuilders are
acetylated hydroxy carboxylic acids and their salts,
which may also be present in lactone form and which
contain at least 4 carbon atoms, at least one hydroxyl
group, and not more than two acid groups. Such
cobuilders are described, for example, in International
Patent Application WO 95/20029.
A further class of substance having cobuilder
properties is represented by the phosphonates. The
phosphonates in question are, in particular,
hydroxyalkane- and aminoalkanephosphonates. Among the
hydroxyalkanephosphonates, 1-hydroxyethane-1,1-diphos-
phonate (HEDP) is of particular importance as a
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cobuilder. It is used preferably as the sodium salt,
the disodium salt being neutral and the tetrasodium
salt giving an alkaline (pH 9) reaction. Suitable
aminoalkanephosphonates are preferably ethylenediamine-
tetramethylenephosphonate (EDTMP), diethylenetriamine-
pentamethylenephosphonate (DTPMP), and their higher
homologs. They are used preferably in the form of the
neutrally reacting sodium salts, e.g., as the
hexasodium salt of EDTMP or as the hepta- and octa-
sodium salt of DTPMP. As a builder in this case,
preference is given to using HEDP from the class of the
phosphonates. Furthermore, the aminoalkanephosphonates
possess a pronounced heavy metal binding capacity.
Accordingly, and especially if the compositions also
contain bleach, it may be preferred to use
aminoalkanephosphonates, especially DTPMP, or to use
mixtures of said phosphonates.
Furthermore, all compounds capable of forming complexes
with alkaline earth metal ions may be used as
cobuilders.
Besides the builders, important ingredients of
detergents include particularly substances from the
groups of the surfactants, bleaches, bleach activators,
corrosion inhibitors, dyes, and fragrances. Important
representatives from the classes of substances
mentioned are described below.
Preferred detergent tablets further comprise one or
more surfactants. In the detergent tablets of the
invention it is possible to use anionic, nonionic,
cationic and/or amphoteric surfactants, and/or mixtures
thereof. From a performance standpoint, preference is
given to mixtures of anionic and nonionic surfactants.
The total surfactant content of the tablets is from 5
to 60% by weight, based on the tablet weight,
preference being given to surfactant contents of more
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than 15% by weight for laundry detergent tablets, while
detergent tablets for machine dishwashing contain
usually less than 3~ by weight of surfactant.
Anionic surfactants used are, for example, those of the
sulfonate and sulfate type. Preferred surfactants of
the sulfonate type are C9_13 alkylbenzenesulfonates,
olefinsulfonates, i.e., mixtures of alkenesulfonates
and hydroxyalkanesulfonates, and also disulfonates, as
are obtained, for example, from Clz-is monoolefins having
a terminal or internal double bond by sulfonating with
gaseous sulfur trioxide followed by alkaline or acidic
hydrolysis of the sulfonation products.. Also suitable
are alkanesulfonates, which are obtained from Clz-la
alkanes, for example, by sulfochlorination or
sulfoxidation with subsequent hydrolysis or
neutralization, respectively. Likewise suitable, in
addition, are the esters of a-sulfo fatty acids (ester
sulfonates), e.g., the a-sulfonated methyl esters of
hydrogenated coconut, palm kernel or tallow fatty
acids.
Further suitable anionic surfactants are sulfated fatty
acid glycerol esters. Fatty acid glycerol esters are
the monoesters, diesters and triesters, and mixtures
thereof, as obtained in the preparation by
esterification of a monoglycerol with from 1 to 3 mol
of fatty acid or in the transesterification of
triglycerides with from 0.3 to 2 mol of glycerol.
Preferred sulfated fatty acid glycerol esters are the
sulfation products of saturated fatty acids having 6 to
22 carbon atoms, examples being those of 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 especially the sodium salts, of the sulfuric
monoesters of Clz-C1g fatty alcohols, examples being
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those of coconut fatty alcohol, tallow fatty alcohol,
lauryl, myristyl, cetyl or stearyl alcohol, or of Clo-
Czo oxo alcohols, and those monoesters of secondary
alcohols of these chain lengths. Preference is also
given to alk (en) yl sulfates of said chain length which
contain a synthetic straight-chain alkyl radical
prepared on a petrochemical basis, these sulfates
possessing degradation properties similar to those of
the corresponding compounds based on fatty-chemical raw
materials. From a detergents standpoint, the Clz-Cls
alkyl sulfates and Clz-Cls alkyl sulfates, and also
C14-Cis alkyl sulfates, are preferred. In addition, 2, 3-
alkyl sulfates, which may for example be prepared in
accordance with US Patents 3,234,258 or 5,075,041 and
obtained as commercial products from Shell Oil Company
under the name DAN~, are suitable anionic surfactants.
Also suitable are the sulfuric monoesters of the
straight-chain or branched C~_zl alcohols ethoxylated
with from 1 to 6 mol of ethylene oxide, such as
2-methyl-branched C9_11 alcohols containing on average
3.5 mol of ethylene oxide (EO) or Clz-is fatty alcohols
containing from 1 to 4 EO. Because of their high
foaming behavior they are used in cleaning products
only in relatively small amounts, for example, in
amounts of from 1 to 5% by weight.
Further suitable anionic surfactants include the salts
of alkylsulfosuccinic acid, which are also referred to
as sulfosuccinates or as sulfosuccinic esters and which
constitute monoesters and/or diesters of sulfosuccinic
acid with alcohols, preferably fatty alcohols and
especially ethoxylated fatty alcohols. Preferred
sulfosuccinates comprise Cs_ls fatty alcohol radicals or
mixtures thereof. Especially preferred sulfosuccinates
contain a fatty alcohol radical derived from
ethoxylated fatty alcohols which themselves represent
nonionic surfactants (for description, see below).
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Particular preference is given in turn to
sulfosuccinates whose fatty alcohol radicals are
derived from ethoxylated fatty alcohols having a
narrowed homolog distribution. Similarly, it is also
possible to use alk(en)ylsuccinic acid containing
preferably 8 to 18 carbon atoms in the alk(en)yl chain,
or salts thereof.
Further suitable anionic surfactants are, in
particular, soaps. Suitable soaps include saturated
fatty acid soaps, such as the salts of lauric acid,
myristic acid, palmitic acid, stearic acid,
hydrogenated erucic acid and behenic acid, and, in
particular, mixtures of soaps derived from natural
fatty acids, e.g., coconut, palm kernel, or tallow
fatty acids.
The anionic surfactants, including the soaps, may be
present in the form of their sodium, potassium or
ammonium salts and also as soluble salts of organic
bases, such as mono-, di- or triethanolamine.
Preferably, the anionic surfactants are in the form of
their sodium or potassium salts, in particular in the
form of the sodium salts.
Surfactants used in machine dishwashing compositions
usually only comprise low-foaming nonionic surfactants.
Representatives from groups of the anionic, cationic or
amphoteric surfactants, on the other hand, have a
relatively minor importance. With particular
preference, detergent tablets of the invention for
machine dishwashing comprise nonionic surfactants.
In particularly preferred embodiments of the present
invention, the detergent tablets of the invention
comprise nonionic surfactants, especially nonionic
surfactants from the group of the alkoxylated alcohols.
Nonionic surfactants used are preferably alkoxylated,
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advantageously ethoxylated, especially primary,
alcohols having preferably 8 to 18 carbon atoms and on
average from 1 to 12 mol of ethylene oxide (EO) per
mole of alcohol, in which the alcohol radical may be
linear or, preferably, methyl-branched in position 2
and/or may comprise linear and methyl-branched radicals
in a mixture, as are commonly present in oxo alcohol
radicals. In particular, however, preference is given
to alcohol ethoxylates containing linear radicals from
alcohols of natural origin having 12 to 18 carbon
atoms, e.g., from coconut, palm, tallow fatty or oleyl
alcohol and on average from 2 to 8 EO per mole of
alcohol. Preferred ethoxylated alcohols include, for
example, Clz-14 alcohols containing 3 EO or 4 EO, C9_11
alcohol containing 7 EO, Cla-is alcohols containing 3 EO,
5 EO, 7 EO or 8 EO, Clz-is alcohols containing 3 EO, 5 EO
or 7 EO, and mixtures thereof, such as mixtures of Clz-~4
alcohol containing 3 EO and Clz-la alcohol containing
5 EO. The stated degrees of ethoxylation represent
statistical mean values, which for a specific product
may be an integer or a fraction. Preferred alcohol
ethoxylates have a narrowed homolog distribution
(narrow range ethoxylates, NREs). In addition to these
nonionic surfactants it is also possible to use fatty
alcohols containing more than 12 EO. Examples thereof
are tallow fatty alcohol containing 14 EO, 25 EO, 30 EO
or 40 EO.
As further nonionic surfactants, furthermore, use may
also be made of alkyl glycosides of the general formula
RO(G)X, where R is a primary straight-chain or methyl-
branched aliphatic radical, especially an aliphatic
radical methyl-branched in position 2, containing 8 to
22, preferably 12 to 18, carbon atoms, and G is the
symbol representing a glycose unit having 5 or 6 carbon
atoms, preferably glucose. The degree of
oligomerization, x, which indicates the distribution of
monoglycosides and oligoglycosides, is any desired
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- - 24 -
number between 1 and 10; preferably, x is from 1.2 to
1.4.
A further class of nonionic surfactants used with
preference, which are 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 having 1 to 4 carbon atoms in the
alkyl chain, especially fatty acid methyl esters, as
are described, for example, in Japanese Patent
Application JP 58/217598, or those prepared preferably
by the process described in International Patent
Application WO-A-90/13533.
Nonionic surfactants of the amine oxide type, examples
being N-cocoalkyl-N,N-dimethylamine oxide and
N-tallowalkyl-N,N-dihydroxyethylamine oxide, and of the
fatty acid alkanolamide type, may be also be suitable.
The amount of these nonionic surfactants is preferably
not more than that of the ethoxylated fatty alcohols,
in particular not more than half thereof.
Further suitable surfactants are polyhydroxy fatty acid
amides of the formula (I),
R1
R-CO-N- [Z] (I)
where RCO is an aliphatic acyl radical having 6 to 22
carbon atoms, R1 is hydrogen or an alkyl or
hydroxyalkyl radical having 1 to 4 carbon atoms, and
[Z] is a linear or branched polyhydroxyalkyl radical
having 3 to 10 carbon atoms and from 3 to 10 hydroxyl
groups. The polyhydroxy fatty acid amides are known
substances which are customarily obtainable by
reductive amination of a reducing sugar with ammonia,
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- - 25 -
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 the polyhydroxy fatty acid amides also
includes compounds of the formula (II)
Ri-O-Rz
R-CO-N- [Z] (II)
where R is a linear or branched alkyl or alkenyl
radical having 7 to 12 carbon atoms, R1 is a linear,
branched or cyclic alkyl radical or an aryl radical
having 2 to 8 carbon atoms and Rz is a linear, branched
or cyclic alkyl radical or an aryl radical or an
oxyalkyl radical having 1 to 8 carbon atoms, preference
being given to C1_4 alkyl radicals or phenyl radicals,
and [Z] is a linear polyhydroxyalkyl radical whose
alkyl chain is substituted by at least two hydroxyl
groups, or alkoxylated, preferably ethoxylated or
propoxylated, derivatives of said radical.
[Z] is preferably obtained by reductive amination of a
reduced sugar, e.g., glucose, fructose, maltose,
lactose, galactose, mannose, or xylose. The N-alkoxy-
or N-aryloxy-substituted compounds may then be
converted to the desired polyhydroxy fatty acid amides,
for example, in accordance with the teaching of
International Patent Application WO-A-95/07331 by
reaction with fatty acid methyl esters in the presence
of an alkoxide as catalyst.
Besides the nonionic surfactants, it is of course also
possible for other substances from the group of the
ionic surfactants, for example, the anionic or cationic
surfactants, to be present in the detergent tablets of
the invention.
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Detergent tablets which are preferred in the context of
the present invention have total surfactant contents of
less than 5% by weight, preferably less than 4~ by
weight, with particular preference less than 3% by
weight, and in particular less than 2% by weight, based
in each case on the tablet.
Among the compounds used as bleaches which yield Hz02 in
water, particular importance is possessed by sodium
percarbonate and sodium perborate monohydrate. Further
bleaches which may be used are, for example, sodium
perborate tetrahydrate, peroxypyrophosphates, citrate
perhydrates, and H202-donating peracidic salts or
peracids, such as perbenzoates, peroxophthalates,
diperazelaic acid, phthaloiminoperacid or diper-
dodecanedioic acid. Cleaning products of the invention
may also comprise bleaches from the group of organic
bleaches. Typical organic bleaches are the diacyl
peroxides, such as dibenzoyl peroxide, for example.
Further typical organic bleaches are the peroxy acids,
particular examples being the alkyl peroxy acids and
the aryl peroxy acids. Preferred representatives are
(a) peroxybenzoic acid and its ring-substituted
derivatives, such as alkylperoxybenzoic acids, and also
peroxy-a-naphthoic acid and magnesium monoperphthalate,
(b) the aliphatic or substituted aliphatic peroxy
acids, such as peroxylauric acid, peroxystearic acid,
s-phthalimidoperoxycaproic acid [phthaloiminoperoxy-
hexanoic acid (PAP)], o-carboxybenzamidoperoxycaproic
acid, N-nonenylamidoperadipic acid and N-nonenylamido-
persuccinates, and (c) aliphatic and araliphatic peroxy
dicarboxylic acids, such as 1,12-diperoxydecane-
dicarboxylic acid, 1,9-diperoxyazelaic acid, diperoxy-
sebacic acid, diperoxybrassylic acid, the diperoxy-
phthalic acids, 2-decyldiperoxybutane-1,4-dioic acid
and N,N-terephthaloyldi(6-aminopercaproic acid) may be
used.
' CA 02314035 2000-07-13
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Bleaches in the detergent tablets of the invention for
machine dishwashing may also be substances which
release chlorine or bromine. Among suitable chlorine-
or bromine-releasing materials, examples include
heterocyclic N-bromoamides and N-chloroamides, examples
being trichloroisocyanuric acid, tribromoisocyanuric
acid, dibromoisocyanuric acid and/or dichloro-
isocyanuric acid (DICA) and/or salts thereof with
cations such as potassium and sodium. Hydantoin
compounds, such as 1,3-dichloro-5,5-dimethylhydantoin,
are likewise suitable.
The bleaches are used in machine dishwashing
compositions usually in amounts of from 1 to 30% by
weight, preferably from 2.5 to 20% by weight, and in
particular from 5 to 15% by weight, based in each case
on the composition. Detergent tablets which are
preferred in the context of the present invention
contain bleaches from the group of the oxygen or
halogen bleaches, especially the chlorine bleaches,
with particular preference sodium perborate and sodium
percarbonate, in amounts of from 2 to 25% by weight,
preferably from 5 to 20% by weight, and in particular
from 10 to 15% by weight, based in each case on the
tablet.
Bleach activators, which boost the action of the
bleaches, may likewise be a constituent of the
detergent tablets of the invention. Known bleach
activators are compounds containing one or more N-acyl
and/or O-acyl groups, such as substances from the class
of the anhydrides, esters, imides and acylated
imidazoles or oximes. Examples are tetra-
acetylethylenediamine TAED, tetraacetylmethylene-
diamine TAMD, and tetraacetylhexylenediamine TAHD, and
also pentaacetylglucose PAG, 1,5-diacetyl-2,2-
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- 28 -
dioxohexahydro-1,3,5-triazine DADHT, and isatoic
anhydride ISA.
Bleach activators which may be used are compounds which
under perhydrolysis conditions give rise to aliphatic
peroxo carboxylic acids having preferably 1 to 10
carbon atoms, in particular 2 to 4 carbon atoms, and/or
substituted or unsubstituted perbenzoic acid. Suitable
substances are those which carry O-acyl and/or N-acyl
groups of the stated number of carbon atoms, and/or
substituted or unsubstituted benzoyl groups. Preference
is given to polyacylated alkylenediamines, especially
tetraacetylethylenediamine (TAED), acylated triazine
derivatives, especially 1,5-diacetyl-2,4-dioxohexa-
hydro-1,3,5-triazine (DADHT), acylated glycolurils,
especially tetraacetylglycoluril (TAGU), N-acyl imides,
especially N-nonanoylsuccinimide (NOSI), acylated
phenolsulfonates, especially n-nonanoyl- or
isononanoyloxybenzenesulfonate (n- or iso-NOBS),
carboxylic anhydrides, especially phthalic anhydride,
acylated polyhydric alcohols, especially triacetin,
ethylene glycol diacetate, 2,5-diacetoxy-2,5-dihydro-
furan, N-methylmorpholiniumacetonitrile methyl sulfate
(MMA), and the enol esters known from German Patent
Applications DE 196 16 693 and DE 196 16 767, and also
acetylated sorbitol and mannitol and/or mixtures
thereof (SORMAN), acylated sugar derivatives,
especially pentaacetylglucose (PAG), pentaacetyl-
fructose, tetraacetylxylose and octaacetyllactose, and
acetylated, optionally N-alkylated glucamine and
gluconolactone, and/or N-acylated lactams, for example,
N-benzoylcaprolactam. Hydrophilically substituted
acylacetals and acyllactams are likewise used with
preference. Combinations of conventional bleach
activators may also be used. The bleach activators are
used in machine dishwashing compositions usually in
amounts of from 0.1 to 20% by weight, preferably from
0.25 to 15% by weight, and in particular from 1 to 10%
CA 02314035 2000-07-13
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by weight, based in each case on the composition. In
the context of the present invention, the stated
proportions relate to the weight of the base tablet.
In addition to the conventional bleach activators, or
instead of them, it is also possible to incorporate
what are known as bleaching catalysts into the base
tablets. These substances are bleach-boosting
transition metal salts or transition metal complexes
such as, for example, Mn-, Fe-, Co-, Ru- or Mo-salen
complexes or -carbonyl complexes. Other bleaching
catalysts which can be used include Mn, Fe, Co, Ru, Mo,
Ti, V and Cu complexes with N-containing tripod
ligands, and also Co-, Fe-, Cu- and Ru-ammine
complexes.
Preference is given to the use of bleach activators
from the group of polyacylated alkylenediamines,
especially tetraacetylethylenediamine (TAED), N-acyl
imides, especially N-nonanoylsuccinimide (NOSI),
acylated phenolsulfonates, especially n-nonanoyl- or
isononanoyloxybenzenesulfonate (n- or iso-NOBS), N-
methylmorpholiniumacetonitrile methyl sulfate (MMA),
preferably in amounts of up to 10% by weight, in
particular from 0.1% by weight to 8% by weight, more
particularly from 2 to 8% by weight, and with
particular preference from 2 to 6% by weight, based on
the overall composition.
Bleach-boosting transition metal complexes, especially
those with the central atoms Mn, Fe, Co, Cu, Mo, V, Ti
and/or Ru, preferably selected from the group of
manganese and/or cobalt salts and/or complexes, with
particular preference from cobalt ammine complexes,
cobalt acetato complexes, cobalt carbonyl complexes,
the chlorides of cobalt or manganese, and manganese
sulfate, are used in customary amounts, preferably in
an amount of up to 5% by weight, in particular from
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0.0025% by weight to 1% by weight, and with particular
preference from 0.01% by weight to 0.25% by weight,
based in each case on the overall composition. In
specific cases, however, it is also possible to use a
greater amount of bleach activator.
Preferred detergent tablets contain bleach activators
from the groups of polyacylated alkylenediamines,
especially tetraacetylethylenediamine (TAED), N-acyl
imides, especially N-nonanoylsuccinimide (NOSI),
acylated phenolsulfonates, especially n-nonanoyl- or
isononanoyloxybenzenesulfonate (n- or iso-NOBS), and N-
methylmorpholiniumacetonitrile methyl sulfate (MMA), in
amounts of from 0.25 to 15% by weight, preferably from
0.5 to 10% by weight, and in particular from 1 to 5% by
weight, based in each case on the tablet.
The detergent tablets of the invention may include
corrosion inhibitors for protecting the ware or the
machine, with special importance in the field of
machine dishwashing being possessed, in particular, by
silver protectants. The known substances of the prior
art may be used. In general it is possible to use, in
particular, silver protectants selected from the group
consisting of triazoles, benzotriazoles, bisbenzo-
triazoles, aminotriazoles, alkylaminotriazoles, and
transition metal salts or transition metal complexes.
Particular preference is given to the use of
benzotriazole and/or alkylaminotriazole. Frequently
encountered in cleaning formulations, furthermore, are
agents containing active chlorine, which may
significantly reduce corrosion of the silver surface.
In chlorine-free cleaners, use is made in particular of
oxygen-containing and nitrogen-containing organic
redox-active compounds, such as divalent and trivalent
phenols, e.g. hydroquinone, pyrocatechol,
hydroxyhydroquinone, gallic acid, phloroglucinol,
pyrogallol, and derivatives of these classes of
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compound. Inorganic compounds in the form of salts and
complexes, such as salts of the metals Mn, Ti, Zr, Hf,
V, Co and Ce, also find frequent application.
Preference is given in this context to the transition
metal salts selected from the group consisting of
manganese and/or cobalt salts and/or complexes, with
particular preference cobalt ammine complexes, cobalt
acetato complexes, cobalt carbonyl complexes, the
chlorides of cobalt or of manganese and manganese
sulfate. Similarly, zinc compounds may be used to
prevent corrosion on the ware.
Preferred detergent tablets contain silver protectants
from the group of the triazoles, benzotriazoles,
bisbenzotriazoles, aminotriazoles, alkylaminotriazoles
and transition metal salts or transition metal
complexes, with particular preference benzotriazole
and/or alkylaminotriazole, in amounts of from 0.01 to
5% by weight, preferably from 0.05 to 4% by weight, and
in particular from 0.5 to 3% by weight, based in each
case on the tablet.
Of course, the tablets of the invention may comprise
enzymes. The enzymes for optional use in the detergent
tablets of the invention are preferably commercially
customary solid enzyme preparations.
Suitable enzymes include in particular those from the
classes of the hydrolases such as the proteases,
esterases, lipases or lipolytic enzymes, amylases,
glycosyl hydrolases, and mixtures of said enzymes. All
of these hydrolases contribute to removing stains, such
as proteinaceous, fatty or starchy marks. For
bleaching, it is also possible to use oxidoreductases.
Especially suitable enzymatic active substances are
those obtained from bacterial strains or fungi such as
Bacillus subtilis, Bacillus licheniformis, Streptomyces
griseus, Coprinus cinereus and Humicola insolens, and
CA 02314035 2000-07-13
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also from genetically modified variants thereof.
Preference is given to the use of proteases of the
subtilisin type, and especially to proteases obtained
from Bacillus lentus. Of particular interest in this
context are enzyme mixtures, examples being those of
protease and amylase or protease and lipase or
lipolytic enzymes, or of protease, amylase and lipase
or lipolytic enzymes, or protease, lipase or lipolytic
enzymes, but especially protease and/or lipase-
containing mixtures or mixtures with lipolytic enzymes.
Examples of such lipolytic enzymes are the known
cutinases. Peroxidases or oxidases have also proven
suitable in some cases. The suitable amylases include,
in particular, alpha-amylases, iso-amylases,
pullulanases, and pectinases.
The enzymes may be adsorbed on carrier substances or
embedded in coating substances in order to protect them
against premature decomposition. The proportion of the
enzymes, enzyme mixtures or enzyme granules may be, for
example, from about 0.1 to 5% by weight, preferably
from 0.5 to about 4.5% by weight. Detergent tablets
which are preferred in the context of the present
invention are those which comprise protease and/or
amylase.
Dyes and fragrances may be added to the detergent
tablets of the invention in order to enhance the
esthetic appeal of the products which are formed and to
provide the consumer with not only the performance but
also a visually and sensorially "typical and
unmistakeable" product. As perfume oils and/or
fragrances it is possible to use individual odorant
compounds, examples being the synthetic products of the
ester, ether, aldehyde, ketone, alcohol, and
hydrocarbon types. Odorant compounds of the ester type
are, for example, benzyl acetate, phenoxyethyl
isobutyrate, p-tert-butylcyclohexyl acetate, linalyl
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' - 33 -
acetate, dimethylbenzylcarbinyl acetate, phenylethyl
acetate, linalyl benzoate, benzyl formate, ethyl
methylphenylglycinate, allyl cyclohexylpropionate,
styrallyl propionate, and benzyl salicylate. The ethers
include, for example, benzyl ethyl ether; the aldehydes
include, for example, the linear alkanals having 8-18
carbon atoms, citral, citronellal, citronellyloxy-
acetaldehyde, cyclamen aldehyde, hydroxycitronellal,
lilial and bourgeonal; the ketones include, for
example, the ionones, a-isomethylionone and methyl
cedryl ketone; the alcohols include anethole,
citronellol, eugenol, geraniol, linalool, phenylethyl
alcohol, and terpineol; the hydrocarbons include
primarily the terpenes such as limonenes and pinene.
Preference, however, is given to the use of mixtures of
different odorants, which together produce an appealing
fragrance note. Such perfume oils may also contain
natural odorant mixtures, as obtainable from plant
sources, examples being pine oil, citrus oil, jasmine
oil, patchouli oil, rose oil or ylang-ylang oil.
Likewise suitable are clary sage oil, camomile oil,
clove oil, balm oil, mint oil, cinnamon leaf oil, lime
blossom oil, juniperberry oil, vetiver oil, olibanum
oil, galbanum oil and labdanum oil, and also orange
blossom oil, neroliol, orange peel oil, and sandalwood
oil.
The fragrances may be incorporated directly into the
detergents of the invention; alternatively, it may be
advantageous to apply the fragrances to carriers.
In order to enhance the esthetic appeal of the
composition of the invention, it (or parts thereof) may
be colored with appropriate dyes. Preferred dyes, whose
selection presents no difficulty whatsoever to the
skilled worker, possess a high level of storage
stability and insensitivity to the other ingredients of
the compositions and to light and possess no pronounced
- CA 02314035 2000-07-13
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affinity for the substrates to be treated with the
compositions, such as glass, ceramic, or plastic
tableware, so as not to stain them.
Detergent tablets which are preferred in the context of
the present invention further contain one or more
substances from the groups of the enzymes, corrosion
inhibitors, scale inhibitors, cobuilders, dyes and/or
fragrances in total amounts of from 6 to 30% by weight,
preferably from 7.5 to 25% by weight, and in particular
from 10 to 20% by weight, based in each case on the
tablet weight.
The above remarks have been based on a tablet, the
present invention not being restricted to the provision
of only single-phase tablets. Rather, it is also
possible for just individual phases, preferably layers,
to have a composition in accordance with the invention
and for the stated advantages to be achieved in this
way. It is possible in this way, for example, to
prepare a two-layer tablet one of whose layers contains
- based on the layer - from 0.1 to 9% by weight of
zeolite and from 20 to 95% by weight of phosphates)
while the other layer may be free from zeolite and/or
phosphate. In this way, the dissolution of one layer
may be accelerated in time relative to another layer.
Of course, the subregion of the tablet that has the
composition according to the invention is not tied to
the layer. Rather, the phase of the tablet which
contains - based on the phase - from 0.1 to 9% by
weight of zeolite and from 20 to 95% by weight of
phosphates) may also possess the form of rings, cores,
coatings, beads, etc. In this way it is possible to
produce ring-core tablets, laminated tablets, inlay
tablets, etc . , in which all the phases or only some of
the phases have the composition according to the
invention and, accordingly, dissolve more rapidly.
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The production of the detergent tablets of the
invention, accordingly, is not restricted to the
compression simply of one particulate premix to form a
tablet. Instead, the tablet may also be designed in
such a way that multilayer tablets are produced
conventionally by preparing two or more premixes which
are compressed with one another. In this case, the
premix which is introduced first is not precompressed
or only gently precompressed, in order to acquire a
smooth top face which extends parallel to the bottom of
the tablet, and final compression to form the finished
tablet takes place after the second premix has been
introduced. In the case of tablets with three or more
layers there is a further, optional precompression
following the addition of each premix, before the
tablet undergoes final compression after the last
premix has been added.
Owing to the increasing technical effort involved,
preference is given in practice to tablets having a
maximum of two layers; i.e., preferred detergent
tablets are those which constitute a two-layer tablet.
Even with this intermediate step in the process of the
invention, advantages may be achieved from the division
of certain ingredients between the individual layers.
For example, preference is given to detergent tablets
wherein one layer comprises one or more bleaches and
the other layer comprises one or more enzymes. It is
not only this separation of bleaches and enzymes which
may bring advantages; in addition, the separation of
bleaches and bleach activators for optional use may be
advantageous, so that preference is given to detergent
tablets of the invention wherein one layer comprises
one or more bleaches and the other comprises one or
more bleach activators.
CA 02314035 2000-07-13
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In the remarks below relating to the further subject
matter of the present invention, the production of a
subregion of the tablet of corresponding composition is
included, even if not mentioned explicitly in each
case.
The present invention further provides a process for
producing detergent tablets by conventionally
compressing a particulate premix, wherein said premix
contains phosphates) in amounts of from 20 to 95% by
weight and a finely divided auxiliary having an average
particle size of less than 100 Vim, preferably less than
40 ~,m, with particular preference less than 20 Vim, and
in particular less than 10 Vim, in amounts of from 0.1
to 9% by weight.
The above remarks relating to preferred properties of
the auxiliaries used in accordance with the invention
(solubility in water, amount, type etc.) apply
completely analogously to the process of the invention.
Particular preference is given, again, to the use of
zeolite, so that in preferred processes the premix
contains zeolite in amounts of from 0.1 to 9% by
weight.
In analogy to the remarks made above in respect of the
tablets of the invention, the preferred embodiments
specified therein (amounts of further ingredients,
substances used, physical parameters, etc.) are also
preferred in the case of the process of the invention.
As described above in the remarks relating to the
tablet, the premix may be composed of a very wide
variety of substances. Depending on the composition of
the premixes for compression, physical parameters of
the premixes may be chosen so as to give advantageous
tablet properties.
CA 02314035 2000-07-13
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For instance, in preferred variants of the first
process of the invention, the particulate premix has a
bulk density of more than 600 g/1, preferably more than
700 g/1, and in particular more than 800 g/1.
In addition, the particle size in the premixes intended
for compression may be established in order to obtain
advantageous tablet properties. In preferred variants
of the process of the invention, the particulate premix
has a particle size distribution in which less than 10%
by weight, preferably less than 7.55 by weight, and in
particular less than 5% by weight, of the particles are
greater than 1600 ~,m or smaller than 200 ~,m. Narrower
particle size distributions are further preferred in
this context. In particularly advantageous process
variants, the particulate premix has a particle size
distribution in which more than 30% by weight,
preferably more than 40% by weight, and in particular
more than 50% by weight, of the particles have a size
of between 600 and 1000 ~,m.
In connection with its implementation, the process of
the invention is not restricted to compressing only one
particulate premix to form a tablet. Rather, the
process may also be extended to the effect that, in a
manner known per se, multilayer tablets are produced by
preparing two or more premixes which are compressed one
atop another. In this case, the first premix introduced
is slightly precompressed in order to acquire a smooth
top face which extends parallel to the tablet base,
and, after the second premix has been introduced, final
compression takes place to form the finished tablet. In
the case of tablets with three or more layers there is
a further, optional precompression following the
addition of each premix before the tablet, after the
addition of the last premix, undergoes final
compression.
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In analogy to the remarks above, preference is given
with this process variant as well to processes wherein
two-layer tablets are produced by compressing two
different particulate premixes onto one another, one of
which comprises one or more bleaches and the other of
which comprises one or more enzymes. Again,
analogously, preferred processes are likewise those
wherein two-layer tablets are prepared by compressing
two different particulate premixes atop one another, of
which one comprises one or more bleaches and the other
comprises one or more bleach activators. Here as well,
preference is given to processes wherein the tablet
produced comprises protease and/or amylase.
The tablets of the invention are produced, as described
in principle above, first of all by dry-mixing the
constituents, some or all of which may have been
pregranulated, and subsequently shaping the dry
mixture, in particular by compression to tablets, in
which context it is possible to have recourse to
conventional processes. To produce the tablets of the
invention, the premix (or premixes in the case of
multiphase tablets) is compacted in a so-called die
between two punches to form a solid compact. This
operation, which is referred to below for short as
tableting, is divided into four sections: metering,
compaction (elastic deformation), plastic deformation,
and ejection.
First of all, the premix is introduced into the die,
the fill level and thus the weight and form of the
resulting tablet being determined by the position of
the lower punch and by the form of the compression
tool. Even in the case of high tablet throughputs,
constant metering is preferably achieved by volumetric
metering of the premix. In the subsequent course of
tableting, the upper punch contacts the premix and is
lowered further in the direction of the lower punch. In
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the course of this compaction the particles of the
premix are pressed closer to one another, with a
continual reduction in the void volume within the
filling between the punches. When the upper punch
reaches a certain position (and thus when a certain
pressure is acting on the premix), plastic deformation
begins, in which the particles coalesce and the tablet
is formed. Depending on the physical properties of the
premix, a portion of the premix particles is also
crushed and at even higher pressures there is sintering
of the premix. With an increasing compression rate,
i.e., high throughputs, the phase of elastic
deformation becomes shorter and shorter, with the
result that the tablets formed may have larger or
smaller voids. In the final step of tableting, the
finished tablet is ejected from the die by the lower
punch and conveyed away by means of downstream
transport means. At this point in time, it is only the
weight of the tablet which has been ultimately defined,
since the compacts may still change their form and size
as a result of physical processes (elastic relaxation,
crystallographic effects, cooling, etc).
Tableting takes place in commercially customary
tableting presses, which may in principle be equipped
with single or double punches. In the latter case,
pressure is built up not only using the upper punch;
the lower punch as well moves toward the upper punch
during the compression operation, while the upper punch
presses downward. For small production volumes it is
preferred to use eccentric tableting presses, in which
the punch or punches is or are attached to an eccentric
disk, which in turn is mounted on an axle having a
defined speed of rotation. The movement of these
compression punches is comparable with the way in which
a customary four-stroke engine works. Compression can
take place with one upper and one lower punch, or else
a plurality of punches may be attached to one eccentric
- CA 02314035 2000-07-13
- 40 -
disk, the number of die bores being increased
correspondingly. The throughputs of eccentric presses
vary, depending on model, from several hundred up to a
maximum of 3000 tablets per hour.
For greater throughputs, the apparatus chosen comprises
rotary tableting presses, in which a relatively large
number of dies is arranged in a circle on a so-called
die table. Depending on model, the number of dies
varies between 6 and 55, larger dies also being
obtainable commercially. Each die on the die table is
allocated an upper punch and a lower punch, it being
possible again for the compressive pressure to be built
up actively by the upper punch or lower punch only or
else by both punches. The die table and the punches
move around a common, vertical axis, and during
rotation the punches, by means of raillike cam tracks,
are brought into the positions for filling, compaction,
plastic deformation, and ejection. At those sites where
considerable raising or lowering of the punches is
necessary (filling, compaction, ejection), these cam
tracks are assisted by additional low-pressure
sections, low tension rails, and discharge tracks. The
die is filled by way of a rigid supply means, known as
the filling shoe, which is connected to a stock vessel
for the premix. The compressive pressure on the premix
can be adjusted individually for upper punch and lower
punch by way of the compression paths, the buildup of
pressure taking place by the rolling movement of the
punch shaft heads past displaceable pressure rolls.
In order to increase the throughput, rotary presses may
also be provided with two filling shoes, in which case
only one half-circle need be traveled to produce one
tablet. For the production of two-layer and multilayer
tablets, a plurality of filling shoes are arranged in
series, and the gently pressed first layer is not
ejected before further filling. By means of an
CA 02314035 2000-07-13
- 41 -
appropriate process regime it is possible in this way
to produce laminated tablets and inlay tablets as well,
having a construction like that of an onion skin, where
in the case of the inlay tablets the top face of the
core or of the core layers is not covered and therefore
remains visible. Rotary tableting presses can also be
equipped with single or multiple tools, so that, for
example, an outer circle with 50 bores and an inner
circle with 35 bores can be used simultaneously for
compresssion. The throughputs of modern rotary
tableting presses amount to more than a million tablets
per hour.
When tableting with rotary presses it has been found
advantageous to perform tableting with minimal
fluctuations in tablet weight. Fluctuations in tablet
hardness can also be reduced in this way. Slight
fluctuations in weight can be achieved as follows:
- use of plastic inserts with small thickness tolerances
- low rotor speed
- large filling shoes
- harmonization between the filling shoe wing rotary
speed and the speed of the rotor
-filling shoe with constant powder height
- decoupling of filling shoe and powder charge
To reduce caking on the punches, all of the
antiadhesion coatings known from the art are available.
Polymer coatings, plastic inserts or plastic punches
are particularly advantageous. Rotating punches have
also been found advantageous, in which case, where
possible, upper punch and lower punch should be of
rotatable configuration. In the case of rotating
punches, it is generally possible to do without a
plastic insert. In this case the punch surfaces should
be electropolished.
CA 02314035 2000-07-13
- 42 -
It has also been found that long compression times are
advantageous. These times can be established using
pressure rails, a plurality of pressure rolls, or low
rotor speeds. Since the fluctuations in tablet hardness
are caused by the fluctuations in the compressive
forces, systems should be employed which limit the
compressive force. In this case it is possible to use
elastic punches, pneumatic compensators, or sprung
elements in the force path. In addition, the pressure
roll may be of sprung design.
Tableting machines suitable in the context of the
present invention are obtainable, for example, from the
following companies: Apparatebau Holzwarth GbR, Asperg,
Wilhelm Fette GmbH, Schwarzenbek, Hofer GmbH, Weil,
Horn & Noack Pharmatechnik GmbH, Worms, IMA
Verpackungssysteme GmbH, Viersen, KILIAN, Cologne,
KOMAGE, Kell am See, KORSCH Pressen AG, Berlin, and
Romaco GmbH, Worms. Examples of further suppliers are
Dr. Herbert Pete, Vienna (AU), Mapag Maschinenbau AG,
Berne (CH), BWI Manesty, Liverpool (GB), I. Holland
Ltd., Nottingham (GB), Courtoy N.V., Halle (BE/LU), and
Medicopharm, Kamnik (SI). A particularly suitable
apparatus is, for example, the hydraulic double-
pressure press HPF 630 from LAEIS, D. Tableting tools
are obtainable, for example, from the following
companies: Adams Tablettierwerkzeuge, Dresden, Wilhelm
Fett GmbH, Schwarzenbek, Klaus Hammer, Solingen, Herber
& Sohne GmbH, Hamburg, Hofer GmbH, Weil, Horn & Noack,
Pharmatechnik GmbH, Worms, Ritter Pharmatechnik GmbH,
Hamburg, Romaco GmbH, Worms, and Notter Werkzeugbau,
Tamm. Further suppliers are, for example, Senss AG,
Reinach (CH) and Medicopharm, Kamnik (SI).
The tablets can be produced in predetermined three-
dimensional forms and predetermined sizes. Suitable
three-dimensional forms are virtually any practicable
designs - i.e., for example, bar, rod or ingot form,
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' - 43 -
cubes, blocks and corresponding three-dimensional
elements having planar side faces, and in particular
cylindrical designs with a circular or oval cross
section. This latter design covers forms ranging from
tablets through to compact cylinders having a height-
to-diameter ratio of more than 1.
The portioned compacts may in each case be formed as
separate, individual elements corresponding to the
predetermined dosage of the detergents. It is equally
possible, however, to design compacts which combine a
plurality of such mass units in one compact, with the
ease of separation of smaller, portioned units being
provided for in particular by means of predetermined
breakage points. For the use of textile detergents in
machines of the type customary in Europe, with a
horizontally arranged mechanism, it may be judicious to
design the portioned compacts as cylindrical or block-
shaped tablets, preference being given to a diameter/
high ratio in the range from about 0.5 . 2 to 2 . 0.5.
Commercially customary hydraulic presses, excentric
presses and rotary presses are suitable equipment in
particular for producing such compacts.
Another preferred tablet which can be produced has a
platelike or barlike structure with, in alternation,
long, thick and short, thin segments, so that
individual segments can be broken off from this "slab"
at the predetermined breaking points, represented by
the short, thin segments, and inserted into the
machine. This principle of the "slablike" tablet
detergent may also be realized in other geometric
forms; for example, vertical triangles connected to one
another lengthwise at only one of their sides.
However, it is also possible for the various components
not to be compressed to a homogeneous tablet, but
instead for tablets to be obtained which have a
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plurality of layers, i.e., at least two layers. In this
case it is also possible for these different layers to
have different dissolution rates. This may result in
advantageous performance properties for the tablets.
If, for example, there are components present in the
tablets which have adverse effects on each other, then
it is possible to integrate one component into the
quicker-dissolving layer and the other component into a
slower-dissolving layer, so that the first component
has already reacted when the second passes into
solution. The layer structure of the tablets may be
realized in stack form, in which case dissolution of
the inner layers) at the edges of the tablet takes
place at a point when the outer layers have not yet
fully dissolved; alternatively, the inner layers) may
also be completely enveloped by the respective
outerlying layer(s), which prevents premature
dissolution of constituents of the inner layer(s).
In one further-preferred embodiment of the invention, a
tablet consists of at least three layers, i.e., two
outer and at least one inner layer, with at least one
of the inner layers comprising a peroxy bleach, while
in the stack-form tablet the two outer layers, and in
the case of the envelope-form tablet the outermost
layers, are free from peroxy bleach. Furthermore, it is
also possible to provide for spatial separation of
peroxy bleach and any bleach activators and/or enzymes
present in one tablet.
Similar effects can also be achieved by coating
individual constituents of the detergent composition
intended for compression, or of the tablet as a whole.
For this purpose the elements to be coated may be
sprayed, for example, with aqueous solutions or
emulsions, or else a coating may be obtained by the
technique of melt coating.
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After compression, the detergent tablets possess high
stability. The fracture strength of cylindrical tablets
can be gaged by way of the parameter of diametral
fracture stress. This diametral fracture stress can be
determined by
2P
~Dt
where a represents the diametral fracture stress (DFS)
in Pa, P is the force in N which leads to the pressure
exerted on the tablet, which pressure causes the
fracture of the tablet, D is the tablet diameter in
meters, and t is the tablet height.
The present invention further provides for the use of
preferably water-insoluble substances having average
particle sizes of less than 100 Vim, preferably less
than 40 Vim, with particular preference less than 20 Vim,
and in particular less than 10 ~,m, as disintegration
aids in phosphate-containing detergent tablets.
In the context of the use in accordance with the
invention as well, the embodiments given as preferred
above for the detergent tablets of the invention and
for the process of the invention are also preferred.
The present invention therefore preferably provides for
the use of zeolite as a disintegration aid in
phosphate-containing detergent tablets. This use of
zeolite in accordance with the invention leads to
tablets having advantageous properties as shown by the
examples below. As far as preferred embodiments of the
use in accordance with the invention are concerned
(particle sizes, further ingredients, composition of
the premix, etc.), the comments made above for the
process of the invention apply analogously. One
particularly preferred embodiment provides for the use
of zeolites in amounts of from 1 to 9~ by weight as
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disintegration aids in detergent tablets having
phosphate contents of between 10 and 95% by weight.
Examples:
By compressing two different premixes, two-layer
rectangular tablets were produced consisting of 68% by
weight of bottom phase and 32% by weight of top phase.
The composition of the top phase was firstly designed
in accordance with the invention (tablet E); in the
comparative tablets, V, zeolite was not used and
instead only phosphate was used. The composition of the
bottom phase was identical for both tablets E and V.
The composition (in % by weight, based on the
respective premix) of the three premixes and thus of
the two different two-phase tablets is shown in the
following table:
Premix 1 Premix 2 Premix 3
(bottom phase(top phase (top phase
S and V) V) E)
Sodium carbonate 32.0 - -
Sodium 52.0 91.4 88.7
tripolyphosphate
Zeolite A - - 2.7
Sodium perborate 10.0 - -
Tetraacetylethylene-2.5 - -
diamine
Benzotriazole 1.0 - -
fatty alcohol 2.5 - -
containing 3 EO
Dye 0.2 0.2
Enzyme 6.0 6.0
Perfume 0.4 0.4
Silicone oil I 2.0 I 2.0
The disintegration rate and solubility of the tablets
is determined in a glass beaker apparatus. A tablet
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- - 47 -
weighing 20 g in a weighed basket was held in a glass
beaker containing one liter of water at 50°C in which a
propellor stirrer rotated at 800 revolutions per
minute. Because the basket was weighed, the
disintegration rate is given by the loss in mass. The
solubility was determined by means of conductivity
measurement, the conductivity value after 40 minutes
being defined as 100% and the values determined being
standardized therewith.
The results of these investigations are shown in the
table below, in which the solubility figures are
collated in % (of the final conductivity) and the
disintegration figures in g (amount already
disintegrated).
Time 8 (Premix V (Premix
[mini 1 + 3) 1 + 2)
Solubility Disintegration SolubilityDisintegration
0 0 0 0 0
5 56 47 45 38
10 81 74 66 59
15 93 87 78 71
100 100 88 88
100 100 94 100
100 100 100 100
4 0 10 0 I --i o O - ~ - 10 10 0
0
The table shows that the tablets E of the invention, in
which the top phase has a composition according to the
20 invention, disintegrate more rapidly and dissolve more
effectively. Whereas the tablets E of the invention
have fallen completely through the basket (i.e., have
disintegrated) and dissolved after just 20 minutes, the
comparative tablets require 25 minutes for
25 disintegration and have dissolved completely only after
30 minutes.
