Note: Descriptions are shown in the official language in which they were submitted.
WO 95/20030 PCTIEP95I00226
1
CO-GRANULES AND DETERGENT TABLETS FORMED THEREFROM
FIELD OF THE INVENTION
This invention relates to co-granules useful in detergent
compositions, and to the preparation of such co-granules.
The invention further relates to compacted forms of
product produced- from the granules, e.g. detergent
tablets. More particularly, the invention relates to co-
granules and tablets formed therefrom, especially of and
for the use in automatic dishwashing compositions.
$ACRGROUND OF THE INVENTION AND PRIOR ART
As used herein, the term "co-granules" means granules
comprising more than one compound or component of an
overall cleaning system. The term "granule" is to be
interpreted broadly and is intended to embrace various
particulate forms such as granulate, coarse powder,
tablets and noodles. As used herein, the term "tablet"
is to be construed as meaning a discretely shaped solid
body of material, of which the shape and dimensions may
vary with the application envisaged, and which may for
example have a weight in the range of from about 1 to
about 100 grams, preferably from about 10 to about 50
grams.
Dishwashing compositions are frequently made up from
granules of one particular inorganic compound such as
e.g. alkali silicate an<9 these compositions often contain
other ingredients, especially organic compounds for
example, in the form of different particles. The
silicate granules for instance often dissolve only. with
difficulty and they lead to the formation of fines
(dust). The dissolution problem is aggravated by the
' fact- that silicate granules having a SiO2:Na20 molar
ratio between 1.8 and 3..0 and a moisture content of below
about 18% dissolve only with considerable difficulty.
CONFIRN9ATION COPY
WO 95/20030 ~ ~' ~ Q 4 3 3 PCTIEP95100226
a
Moreover, segregation of different kinds of granular
components (e. g. a bleach system and enzymes) can occur.
Furthermore, alkali silicate granules with a homogeneous
distribution of moisture are difficult to obtain, often
as a consequence of the drying process, since less
moisture tends to be present in the outer skin and more
in the inside of the granules. This also reduces the
solubility of the granules during use. Generally
speaking, the preparation of granules of builder
materials, e.g. phosphate-replacing builders like di-,
tri- or tetracarboxylic -acid -and salts thereof, is
difficult and therefore relatively expensive. The
economics of granule manufacturing processes are
therefore important.
Co-granules useful in detergent compositions are known
inter alia from EP-A-0421664 (Rohm and Haas Company),
which discloses a polymer-containing granulate containing
at least 20% by weight of polymer and at least 20% by
weight of a water-soluble inorganic compound. Such
compounds are preferably sulphates, carbonates or
silicates. In detergent compositions comprising the
polymer-containing granules, other phosphate-replacing
builders may also be present, such as zeolites,
carbonates, nitrilotriacetic acid, citric acid, tartaric
acid, salts thereof, phosphonates etc. The examples in
the reference disclose granules containing polymer and
sodium sulphate or sodium carbonate.
EP-A-0561452 (Unilever) discloses phosphate-free machine
dishwashing compositions comprising a polyamino acid and
an anti-scaling agent. Various builder salts may be
included in the disclosed compositions, including
preferably citrates, alkenylsuccinates, carbonates,
bicarbonates, zeolites and mixtures thereof, but the
WO 95/20030 ~ ~ ~ ~ ~ ~ PCTIEP95100226
3
amount of a carbonate and/or bicarbonate builder in the
composition is limited to 50~ by weight.
CH-A-673033 (Cosmina AG) discloses phosphate- and
trisodiumnitriloacetate-free alkaline machine dishwashing
compositions comprising sodium citrate, at least one
sodium salt of hydroxyethanediphosphonic acid and at
least one sodium silicate.
JP-A-49076905 (Lion) discloses spray-dried powder
detergents comprising, inter alia, inorganic and organic
builder salts. In the agglomeration process, once
granules of the desired uniform diameter are achieved,
the agglomeration is stopped by treating them with a salt
selected from a polyphosphate, carbonate, sulphate,
silicate and/or sodium citrate.
JP-A-54106509 (Lion) discloses the preparation of spray-
dried granulated detergent compositions comprising a
surfactant, an alkali metal silicate salt and a phosphate
salt. In the process the SiOZ:M20 molar ratio in the
silicate is controlled using an acid type surfactant or
2o an organic acid such as citric acid.
It is one object of the present invention, therefore, to
provide co-granules having good solubility in water,
giving less fines during handling, having a more even
distribution of moisture within the granules, preventing
segration of at least those ingredients included in the
co-granules, and which can be prepared by convenient and
economical-techniques.
In the manufacture of granular and powder detergent
' products, various drying and/or granulation techniques
are known.
W 0 95/20030 PCT/EP95/00226
218Q4~a
4
In EP-A-0526978 for instance is disclosed the
simultaneous drying and granulation of silicates in a
turbine dryer, e.g. a turbogranulation dryer ex. Vomm- ,
Turbo Technology, VOMM IMPIANTI E PROCESSI S.r.l., Milan,
Italy. However, this dryer is less suited for the
combined drying and granulation to produce co-granules
containing substantial quantities of organic ingredients
in conjunction with silicate. Due to the high attrition
between the rotating blades and the film formed on the
wall during the granulation phase, local overheating can
cause partial decomposition of the organic ingredients,
leading to (local-) colouring.
Drying can also conveniently be achieved by spray drying
a slurry by a conventional technique using a spray tower
in which the slurry is atomized and dried in a hot air
stream. In order to obtain a granular detergent product,
spray drying must be followed by a granulation step (e. g.
using a L&dige Ploughshare mixer), optionally after
milling. For granulation usually a small amount of
moisture is added.
The powders obtained in a turbine dryer generally have a
wider particle size distribution as part of the product
gathers at the walls, creating larger particles.
Furthermore powder particles obtained in a turbine dryer
are less homogeneously dried as a result of the larger
particles being more effectively dried at the outside
than on the inside and as a result of the difference in
residence time between particles remaining in the gas
stream and those sticking on the (heated) wall of the
dryer.
It is also possible to spray slurry onto fine particles '
while drying to form gradually growing granules. This
can be performed in e.g. an AGT-unit for continuous
WO 95120030 ~ ~ ~, PCTIEP95I00226
drying and granulation, ex Glatt-GmbH/Process Technology,
Binzen, LSrrach, Germany.
Another possibility is to spray slurry in a rotary drum
granulator onto fines to build up coarser particles,
5 followed by, or in conjunction with, drying. Such spray
on techniques lead to granules with a more homogeneous
distribution of moisture and consequently a better
solubility.
It is a further object of the present invention,
therefore, to provide a dried powder or granulated
detergent product which shows less dust problem as a
consequence of higher attrition resistance of the
particles, a more homogeneous distribution of moisture in
the particles, minimisation of the risk of segregation of
various ingredients in the detergent compositions.
Dishwashing tablets are frequently produced from a
mixture containing granules of one particular inorganic
compound, such as e.g. alkali metal silicate, and
additionally other ingredients, such as organic builder
salts, as separate particles.
There are currently tablets on the market that contain
citric acid or its sodium salt as an organic builder. It
is known that such tablets may be easily fragmented or
broken during handling due to the crystalline nature of
the organic builder salt. This is especially evident for
builder salt levels of more than 20% by weight and may
become a serious prablem for preferred builder salt
levels of more than 30% by weight.
It has, therefore, been proposed to add binder material
' 30 that can hold the tablet ingredients together so as to
obtain stronger tablets. However, such binding material
has a negative influence on the rate of tablet
CA 02180433 1999-06-07
WO 95/20030 PCT/EP95/00226
6
dissolution such that cleaning performance during the
washing cycle may be deteriorated.
It has been found that detergent tablets can more easily
be formed if a fine grade or powder-form builder salt,
such as sodium citrate, is used instead of the granular
grades of sodium citrate that are normally used in
machine dishwashing powders. However, increasing the
level of fine citrate leads to poor flow properties of
the base powder and, thus to poor die filling during the
tabletting process. As a consequence of this, a large
variation in individual tablet weights is obtained.
It is yet a further object of the present invention,
therefore, to provide detergent tablets which solve or
ameliorate the above problems and particularly have
adequate strength and dissolution properties.
SL1MMA~tY OF THE INVENTION
Accordingly, in a first aspect the present invention
provides a homogeneous co-granule comprising
(i) a salt of a di-, tri-, or tetracarboxylic acid which is an alkali metal
salt
2o of citric acid, mellitic acid, oxydisuccinic acid,
carboxymethoxysuccinic acid, malonic acid, dipicolinic acid or
alkenyl succinic acid;
(ii) an inorganic salt which is selected from alkali metal silicate, alkali
metal carbonate, alkali metal bicarbonate, alkali metal
sesquicarbonate, alkali metal sulphate, alkali metal and
tripolyphosphate, and mixtures thereof and;
(iii) at least one polymeric compound being either acid and/or salt,
selected from the group consisting of polycarboxylic acid polymers
and polypeptides.
CA 02180433 1999-06-07
6a
According to this first aspect, the invention also
provides a process for the preparation of the above-
defined co-granules, comprising preparing a slurry or
solution of the ingredients of the co-granules, drying
the mixture using any of various suitable known
techniques, and granulating the resulting material.
In a second aspect the present invention provides a
detergent composition comprising at least 25% by weight,
preferably at least 40% by weight, more preferably at
least 50% by weight, of co-granules according to the
first aspect of the invention. Preferably the detergent
WO 95120030 '? ~ ~ ~ ~ ~ ~ PCTIEP95I00226
7
composition comprises a bleach system and/or an enzyme
system. In preferred embodiments of this second aspect
of the invention the detergent composition is formed from
the co-granules, with or without other ingredients.
In a third aspect th.e present invention provides a
detergent tablet comprising from about 25 to about 100%
by weight, preferably from about 25 to about 90% by
weight, of co-granules according to the first aspect of
the invention. Preferably, the tablet -includes a
bleaching system and/or an enzyme system.
According to a fourth aspect, the present invention
further provides the use of a co-granule containing
granular detergent composition or detergent tablet
according to the invention, in a machine dishwashing
process.
DETATr.ED DESCRIPTION OF THE INVENTION AND PREFERRED
The various aspects of the invention, and preferred
features and embodiments thereof, will now be described
in detail.
Co-granules
In the co-granules of the invention the salt of a
di-, tri- or tetracarboxylic acid is especially an alkali
metal salt of citric acid, mellitic acid, oxydisuccinic
acid, carboxymethoxysuccinic acid, malonic acid,
dipicolinic acid or allcenyl succinic acid. Part of the
di-, tri- and tetracarboxylic acid component, e.g. up to
about 30%, may if desired be replaced by a lower hydroxy
monocarboxylic acid, e.g. lactic acid.
Partial salts of the di-, tri- or tetracarboxylic
acid in which one or more of the hydrogen ions of the
WO 95/20030 ~ ~ 8 Q 4 .~ ~ P~~P9S~226
8
carboxylic groups are replaced by metal ions are
particularly useful. Especially sodium and potassium
salts can be used with good results for the purpose of
the invention. Potassium salts are sometimes preferred
because of their higher solubility. The use of alkali
metal citrate, especially sodium citrate, in the co-
granules according to the present invention is preferred.
The use of sodium oxydisuccinate is also preferred.
The inorganic-salt component ofthe co-granule of the
invention is preferably selected from alkali metal
silicate, alkali metal carbonate or bicarbonate, alkali
metal sesquicarbonate, and mixtures thereof. Sodium
silicate is a preferred inorganic salt and, when used, a
composition satisfying Si02 . Na20 - 1.0 - 3.3,
preferably 1.8 to 2.8, e.g 1.8 - 2.3, is particularly
recommended. Alkali metal disilicates, in particular
sodium disilicate, are especially preferred.
In other preferred embodiments of the co-granule of the
invention the co-granule material also comprises at least
one polymeric compound, being either acid and/or salt,
selected from the group consisting of polycarboxylic acid
polymers and polypeptides.
Suitable polycarboxylic acid polymers comprise e.g. a
water-soluble homopolymer or copolymer having a molecular
weight of at least 500. It may be derived Prom a
monocarboxylic acid or from a di-, tri- or polycarboxylic
acid. The polymer will normally be used in the form of
its water-soluble alkali metal salt.
One group of polymer materials found to be of value
comprises homopolymers derived from a monomer of the
formula:
WO 95/20030 ~ ~ ~ ~ ~ ~ ~ PCTfEP95100226
9
R1 H
C - C
COOM RZ
wherein R1 is hydrogen, hydroxyl, C1-C4 alkyl or alkoxy,
acetoxy, or -CHZCOOM; R2 is hydrogen, C1-C4 alkyl or -
COOM and M is an alkali metal. Examples of this group
include the sodium and potassium salts of polyacrylic,
polymethacrylic, polyitaconic, polymaleic and
polyhydroxyacrylic acids and also the hydrolysis products
of the corresponding polymerised acid anhydrides. Thus
the polymer obtained by hydrolysis of malefic anhydride
falls within this group.
A second group of suitable polymeric-materials comprises
the copolymers of two or more carboxylic monomers of the
above formula. Examples of this group include the sodium
and potassium salts of copolymers of malefic anhydride
with acrylic acid, methacrylic acid, crotonic acids,
itaconic acid and its anhydride and/or aconitic acid.
A third group of suitable polymeric materials comprises
the copolymers of one carboxylic monomer of the above
formula and two or more non-carboxylic acid monomers such
as ethylene, propylene, styrene, alpha-methylstyrene,
acrylonitrile, acrylamide, vinylacetate,
methylvinylketone, acrolein and esters of carboxylic acid
monomers such as ethyl acrylate and methacrylate.
Suitable polypeptides which can be incorporated in the
co-granules according 'to the present invention include
for example poly-aspari:ate and polyglutamate.
In further preferred embodiments of the co-granule of the
W0 95120030 PCTlEP95/00226
invention the co-granule material also comprises at least
one inorganic salt selected from the group consisting of
alkali metal tripolyphosphate, alkali metal carbonate,
alkali metal bicarbonate, alkali metal sili-cate, alkali
5 metal sesquicarbonate and alkali metal sulphate. One of
the advantages of incorporating such an inorganic salt is
that it increases the solubility of the co-granule,
especially if the co-granule contains silicates with
SiOZ:Na20 >2.4, because these salts dissolve rapidly and
10 thereby convert the co-granule into an open sponge-like
structure so that the surface area of the co-granule is
increased. This leads to an increase of the solubility
of the remaining solid material of the co-granule.
Most of the salts also act as a builder, reinforcing
detergent activity. Non-phosphate inorganic salts such
as various carbonates, especially alkali metal
carbonate/bicarbonate/sesquicarbonate are preferred. In
the co-granule the inorganic salts are usually present in
the form of their lower stable hydrate(s).
In particular preferred embodiments of the co-granule of
the invention, the co-granule has the following
composition (I) (all amounts being approximate):
1 (or 5) - 90% (w/w) alkali metal silicate, carbonate,
bicarbonate or sesquicarbonate;
5 - 90% (w/w) alkali metal salt of di-, tri- or
tetracarboxylic acid;
0 - 20% (w/w) polymer;
0 - 40% (w/w) alkali metal tripolyphosphate;
0 - 40% (w/w) alkali metal (bi)carbonate or
sesquicarbonate; '
0 - 20% (w/w) organic phosphonate;
0 - 60% (w/w) alkali metal sulphate;
WO 95/20030 PCTlEP95100226
11
0 - 10% (w/w) of minor ingredients;
1 - 25% (w/w) moisture.
The organic phosphonates which can be present in the co-
granule include for example those of the DequestR range,
which are especially added as builders to phosphate-free
machine dishwashing compositions. A drawback of these
polymers however is that some of them are not quite
biodegradable and are therefore environmentally less
acceptable. Therefore some of the polyphosphonates,
whilst being effective, are less acceptable as being P-
containing products.
In especially preferred embodiments of the co-granule of
the invention, the co-granule has the following
composition (II) or alternatively the following
compositions (III) or (IV) (all amounts being
approximate):
- 50 (or up to 75)% (w/w) alkali metal silicate,
carbonate, bicarbonate or sesquicarbonate;
20 25 (or 40) - 75% (w/w) alkali metal salt of di-, tri- or
tetracarboxylic acid;
1 - 9% (w/w) polymer;
1 - 36% (w/w) alkali metal tripolyphosphate;
1 - 36% (w/w) alkali metal (bi)carbonate or
sesquicarbonate;
0 - 37 (or up to 60)% (w/w) alkali metal sulphate;
0 - 9 (w/w) organic phosphonate;
0 - 5% (w/w) of minor ingredients;
3 - 20% (w/w) moisture
W0 95/20030 PCTlEP95100226
2~80~3~
12
III
5-95% (w/w) alkali metal silicate, carbonate, bicarbonate
or sesquicarbonate;
0-60% (w/w) alkali metal salt of di-, tri- or ,-
tetracarboxylic-acid;
5-60% (w/w) polymer;
5-25% (w/w) moisture.
15-75% (w/w) alkali metal silicate, carbonate,
bicarbonate or sesquicarbonate;
25-85% (w/w) alkali metal salt of di-, tri- or
tetracarboxylic acid;
0-20% (w/w) organic phosphonate;
0-60% (w/w) alkali metal sulphate;
0-10% (w/w) nonionic surfactant;
0-5% (w/w) of minor ingredients;
1-25% (w/w) moisture.
Under minor ingredients which may optionally be present
in the co-granule of the invention are here to be
understood various known adjunct materials commonly found
in cleaning compositions, such as: enzyme stabilizers,
such as the poly-alcohols, e.g. glycerol, and borax;
anti-scaling agents; corrosion inhibitors, e.g. zinc
salts, aluminium salts, benzotriazole, etc; crystal-
growth inhibitors; threshold agents; thickening agents;
anionic surfactants; perfumes and dyestuffs;
preservatives.
Also a small amount of preferably low- to non-
foaming nonionic surfactant, which includes any
alkoxylated nonionic surface-active agent wherein the
alkoxy moiety is selected from the group consisting of
WO 95120030 ' PCTfEP95100226
13
ethylene oxide, propylene oxide and mixtures thereof, is
preferably used to improve the detergency and to suppress
excessive foaming due to protein soil. However, an
excessive proportion of nonionic surfactant should be
avoided. Normally, an amount of up to 7% by weight, e.g.
0.1 to 5% by weight, preferably from 0.5 to 4% by weight,
is quite sufficient.
Examples of suitable nonionic surfactants for use in
the co-granule material of the invention are the low- and
non-foaming ethoxylated straight-chain alcohols of the
PlurafacR RA series, supplied by the Eurane Company; of
the LutensolR LF series, supplied by the BASF Company and
of the TritonR DF series, supplied by the Rohm & Haas
Company.
Although the particle size of the co-granules
according to the present invention is not critical, co-
granules are preferred which have an average particle
size of from about 100 to about 1500 microns. More
particularly there is a preference for co-granules having
an average particle size of from about 300 to about 900
microns especially from about 500 to about 700 microns,
and a Rosen Rammler N~-value above about 2.5. Particle
size determination and the definition and determination
of the Rosen Raromler N-value are described in detail in
~Small Particle Statis~tics~~ by Herdan, E; second revised
edition; Butterworth, London 1960, in particular pp 86-
101. Graph paper according to DIN 1171 (new) is often
used to determine the N-value.
The present invention also provides, within its
first aspect, a process for the preparation of the co-
granules, which process comprises preparing a slurry of
the ingredients of the co-granule and drying the mixture
by means of suitable equipment, e.g.-a turbine dryer such
W0 95120030 PCTBP95100226
14
as a turbogranulation drier-ex Vomm-Turbo Technology,
Vomm Impianti E Processi S.r.l., Milan, Italy.
An alternative to drying using a turbine drier, and
especially preferred, is spray-drying the slurry by a
conventional technique using a spray tower in which the
slurry is atomized and dried in a hot air stream. If
desired, the resulting particles may be milled and/or
restructured, for example in a granulation process, e.g.
using a LSdige recycler, a Lodige plough share mixer, or
any other suitable apparatus, such as a twin roll
compactor. Any restructuring stage does not need to be
limited to the material produced by spray-drying and
optionally then milled, which is used as an example only.
The granulation process involves combining fine solid
particles like citrate, carbonates, sulphate; silicates,
tripolyphosphate or co-granules as described above. Heat
sensitive components of the granules, e.g. sodium
bicarbonate, may also be added at this stage, as the
temperature during granulation in e.g. a Lodige recycler
and a L&dige plough share mixer followed by fluid bed
drying to remove excess moisture, should always be below
about 100°C. This is much lower than with turbine driers
which usually operate at around 300°C. Minor ingredients
that -are used in the final powder or granulate
formulation that are available in liquid or fine powder
form, e.g. surfactant, perfume, dyes, organic
phosphonate, corrosion inhibitors, may also be added as
required. Turbine driers usually operate at around 300°C.
In a particularly preferred process the slurry is sprayed
onto fine (recycled) particles and dried to form
gradually growing co-granules. Particularly favoured are
processes that separate fine particles from the coarser
ones, preferably continuously, and recirculate the fines
to the fluidized bed for further spraying-on. Particles
WO 95/20030 PCTIEP95I00226
of the desired size can then be separated from the
process at the appropriate time. Suitable equipment for
continuous drying and granulation is e.g. an AGT-unit ex
Glatt-GmbH/Process Technology, Binzen, Lorrach, Germany.
5 Another attractive possibility is to spray the slurry in
a rotary drum granulator onto (recirculated) fines to
build up coarser particles, followed by, or in
conjunction with, drying. These spraying-on techniques
lead to co-granules with a particularly homogeneous
10 distribution of moisture, often better than for example
those obtained by the use of a turbine dryer. Thus, such
spraying-on techniques yield co-granules of a better
solubility.
In the process of preparing the co-granules it is of
15 course possible to use the various ingredients in the
form of dry or hydrated solid forms and add water to form
a slurry which is then processed as outlined above. It
is however often advantageous to employ a process
comprising preparing a slurry by adding di-, tri- or
tetracarboxylic acid to a solution containing the
inorganic salt(s), neutralizing the carboxylic acids)
with alkali, optionally adding further ingredients, so as
to obtain a slurry with a water content of from about 30
to about 60% (w/w), and converting the slurry into co-
granules by any of the techniques described above,
preferably by a granulation/drying technique.
Preferably, the co-granules of this aspect of the
invention have a bulk density of at least about 700
g/dm3, more preferably above about 800 g/dm3, and most
preferably a bulk density between about 900 g/dm3 and
about 1200 g/dm3. High bulk densities are desirable at
present, to be able to provide final detergent
compositions with a relatively high specific weight.
WO 95/20030 PCT/EP95100226
16
Deteroerit compositions
The present invention also provides, in a second aspect,
a detergent composition which comprises at least about
25% by weight, preferably at least about 40% by weight,
more preferably at least about 50% by weight of co-
granules according to the first aspect of the invention.
Preferably the composition includes a bleach system
and/or an enzyme system, which usually may be added to
the co-granules in the form of separate particles which
may have the same particle size distribution as the co-
granules. Also it is usually advantageous if the bulk
density of the bleach/enzyme particles is comparable to
that of the co-granules.
Preferred forms of detergent composition consist of at
least about 50% by weight of the co-granules and less
than about 30% by weight of a bleach system and an enzyme
system. Preferably the detergent composition is non-
irritant.
Enzymes are used for many purposes in various fields
where biochemical reactions occur. In general, an enzyme
can be described as a catalyst capable of permitting a
biochemical reaction to quickly occur and can be
classified according to the type of reaction they
catalyze. Enzymes are characterized by high specificity;
that is to say, each enzyme can catalyze a single
reaction of one substance or a very small number of
closely related substances.
Examples of enzymes suitable for use in the cleaning
compositions of this invention include lipases,
peptidases, amylases (amylolytic enzymes) and others
which degrade, alter or facilitate the degradation or
alteration of biochemical soils and stains encountered in
cleansing situations so as to remove more easily the soil
WO 95/20030 ~ ~ ~ ~ ~ ~ ~ PCTfEP95100226
17
or stain from the object being washed or to make the soil
or stain more removab7.e in a subsequent cleansing step.
Both degradation and alteration can improve soil
removability. Well-known and preferred examples of these
enzymes are proteases, lipases and amylases. Lipases are
classified as EC class 3, hydrolases subclass EC 3.1,
preferably carboxylic ester hydrolases EC 3.1.1. An
example thereof are lipases EC 3.1.1.3 with the
systematic name glycerol ester hydrolases. Amylases
belong to the same general class as lipases, subclass EC
3.2, especially EC 3.2.1 glycose hydrolases such as
3.2.1.1. alpha-amylase with the systematic name alpha-
1,4-glucan-4-glucanohydrolase; and also 3.2.1.2, beta-
amylase with the systematic name alpha-1,4-glucan
maltohydrolase. Proteases belong to the same class as
lipases and amylases, subclass EC' 3.4, particularly EC
3.4.4 peptide peptido-hydrolases such as EC 3.4.4.16 with
the systematic name su,btilopeptidase A.
Obviously, the foregoing classes should not be construed
as limiting the scope of enzyme-containing embodiments of
compositions according to the invention. Enzymes serving
different functions can also be used in the practice of
this aspect of the invention, the selection depending
upon the composition of biochemical soil, intended
purpose of a particular composition, and the availability
of an enzyme to degrade or alter the soil.
Lipases, sometimes called esterases, hydrolyze fatty
soils. Lipases suitable for use herein include those of
animal, plant and microbiological origin. Suitable
lipases are also found in many strain of bacteria and
fungi. For example, lipases suitable for use herein can
be derived from Pseudomonas, Aspergillus, Pneumococcus,
Staphylococcus, Toxins, Mycobacterium Tuberculosis,
Mycotorula Lipolytica, and Sclerotinia microorganisms,
W0 95/20030 PCTIEP95100226
18
and can be made using recombinant DNA manufacturing
techniques.
Suitable animal lipases are found in the body fluids and
organs of many species. A preferred class of animal
lipase herein is the pancreatic lipase.
Lipase may be employed in the present cleaning
compositions in an amount of from about 0.005% to about
10%, preferably from about 0.01 to about 5% by weight of
the composition, on a pure enzyme basis.
The enzyme most commonly used in machine dishwashing
compositions are amylolytic enzymes.
The amyloltic enzymes for use in the present invention
can be those derived from bacteria or fungi. Preferred
amylolytic enzymes are those prepared and described in
GB-A-1,296,839, cultivated from the strains of Bacillus
licheniformis NCIB 8061, NCIB 8059, ATCC 6334, ATCC 6598,
ATCC 11 945, ATCC 8480 and ATCC 9945 A. Examples of such
amylolytic enzymes are amylolytic enzymes produced and
distributed under the trade name of SO-95R or TermamylR
by Novo Industria A/S, Copenhagen, Denmark. These
amylolytic enzymes are generally presented as granules
and may have enzyme activities of from about 2 to 10
Maltose units/milligram.
The amylolytic activity can be determined by the method
as described by P.Bernfeld in "Method of Enzymology",
Vol. I (1955), page 149.
The composition of this aspect of the invention
preferably also contains a proteolytic enzyme.
Examples of suitable proteolytic enzymes are the
WO 95!20030 ~ ~ ~ PCTJEP95100226
19
subtilisins which=areobtained from particular strains of
B. subtilis and B. licheniformis, such as the
commercially available subtilisins MaxataseR, supplied by
Gist-Brocades N.V., Delft, Holland, and AlcalaseR,
supplied by Novo Industri A/S, Copenhagen, Denmark.
Particularly suitable is a protease obtained from a
strain of Bacillus having maximum activity throughout the
pH range of 8-12, being commercially available from Novo
Industri A/S under the registered trade names of
EsperaseR and SavinaseR. The preparation of these and
analogous enzymes is described in GB-A-1243784.
Another suitable protease useful herein is a fairly
recent commercial product sold by Novo Industri A/S under
the trade name Durazym~, as described in WO-A-89/06279.
The enzymes are generally presented as granules, e.g.
marumes, prills, T-granules etc., and may have enzyme
activities of from about 500 to 1700 glycine
units/milligram. The proteolytic activity can be
determined by the method as described by M.L. Anson in
°°Journal of General Physiology°°, Vol. 22 (1938),
page 79
(one Anson Unit/g = 733 Glycine Units/milligram).
All of these enzymes may each be present in a weight
percentage amount of from about 0.2 to about 5% by
weight, such that for amylolytic enzymes the final
composition may have amylolytic activity of from about
10Z to about 106 Maltose units/kg, and for proteolytic
enzymes the final composition may have proteolytic enzyme
activity of from about 106 to about 109 Glycine Units/kg.
Preferably enzyme material is present in the compositions
of the invention in a total amount of up to about 10% by
weight.
W095/20030 PCTlEP95100226
2~~Q43~
zo
The detergent composition may also comprise a bleach
system, which may or may not-be encapsulated. The bleach
system may be a chlorine- or bromine-releasing agent or
a peroxygen compound. For environmental reasons, a
peroxygen-based bleaching system is preferred. Suitable -
peroxygen compounds may be selected from alkali metal
peroxides, organic peroxides such as urea peroxide, and
inorganic persalts such as the alkali metal perborates,
percarbonate, perphosphates, persilicates and
persulphates. Mixtures of two or more such compounds may
also.be suitable.
Particularly preferred peroxygen compounds are sodium
perborate tetrahydrate and, especially, sodium perborate
monohydrate. Sodium perborate monhydrate is preferred
because of its high active oxygen content. Sodium
percarbonate may also be preferred for environmental
reasons.
Organic peroxy acids or the precursors therefor may also
be utilized in the bleach system. The peroxyacids usable
in the present invention are solid and, preferably,
substantially water-insoluble compounds. By
"substantially water-insoluble" is meant herein a water-
solubility of less than about 1% by weight at ambient
temperature. In general, peroxyacids containing at least
about 7 carbon atoms are sufficiently insoluble in water
for use herein.
Typical monoperoxy acids useful herein include alkyl
peroxy acids and aryl peroxyacids such as:
(i) peroxybenzoic acid and ring-substituted
peroxybenzoic acids, e.g. peroxy-alpha-naphthoic acid;
(ii) aliphatic and substituted aliphatic
monoperoxy acids, e.g. peroxylauric acid and
~. WO 95/20030 ~ ~ ~ ~ ~ ~ ~ PC'TIEP95I00226
z1
peroxystearicacid;
(iii) phthaloyl amido peroxy caproic acid (PAP).
Typical diperoxy acids useful herein include alkyl
diperoxy acids and aryldiperoxy acids, such as:
(iv) 1,12-diperoxydodecanedioic acid (DPDA);
(v) 1,9-diperoxyazelaic acid;
(vi) diperoxybrassylic acid; diperoxysebacic
acid and diperoxyisophthalic acid;
(vii) 2-decyldiperoxybutane-1,4-dioic acid.
Peroxyacid bleach precursors are well known in the art.
As non-limiting examples can be named N,N,N'N'-
tetraacetyl ethylene diamine (TAED), sodium
nonanoyloxybenzene sulphonate (SNOBS), sodium
benzoyloxybenzene sulphonate (SBOBS) and the cationic
peroxyacid precursor (SPCC) as described in US-A-4751015.
Among suitable reactive chlorine- or bromine-oxidizing
materials are heterocyclic N-bromo- and N-chloro imides
such as tri-chlorois:ocyanuric, tribromoisocyanuric,
dibromoisocyanuric and dichloroisocyanuric acids, and
salts thereof with water-solubilizing cations such as
potassium and sodium. Hydantoin compounds such as 1,3-
dichloro-5,5- dimethyl-hydantoin are also quite suitable.
Dry, particulate, water-soluble anhydrous inorganic salts
are likewise suitable for use herein such as lithium,
sodium or calcium hypochlorite and hypobromite.
Chlorinated trisodium phosphate is another suitable
material. Chloroisocyanurates are, however, the
preferred bleaching agents. Potassium
dichlorosocyanurate is sold by Monsanto Company as ACL-
59R. Sodium dichloroi.socyanurates are also available
from Monsanto as ACL-60~, and in the dihydrate form, from
the Olin Corporation as Clearon CDB-56R, available in
WO 95!20030 PCT/EP95100226
~1'8~433
22
powder form (particle diameter of less than 150 microns);
medium particle size (about 50 to 400 microns); and
coarse particle size (150-850 microns). Very large
particles (850-1700 microns) are also found to be
suitable also for encapsulation.
If desirable, a bleach catalyst, such as the manganese
complex, e.g. Mn-Me TACN, as described in EP-A-0458397,
or the sulphonimines of US Patents 5,041,232 - and
5,047,163, may be incorporated in the composition. Such
bleach catalysts may suitably be presented in the form
of a second encapsulate separately from the bleach
capsule component.
For chlorine bleaches the amount of encapsulates used in
the compositions of the invention may vary preferably
within the range of from about 0.1 to about i0%,
especially from about 0.5 to about 3% as available
chlorine (Av C1). For peroxygen bleaching agents a
suitable preferred range will be from about 0.1 to about
20%, especially from about 0.1 to about 10%, preferably
from about 0.5 to about 3 or 5% Av O (available oxygen).
In especially preferred detergent compositions according
to the invention, in order that they are substantially
non-irritant, the amount of peroxygen bleach, silicate
and, carbonate, protease and surfactant taken together is
at most about 20% by weight,- more especially preferably
between about 10 and 19.95% by weight of the composition.
Detergent Tablets
According to the third aspect of-the present invention,
there is provided a detergent tablet comprising from
about 25 to about 100%, preferably from about 25 to about
90% by weight, more preferably from about 40 to about 90%
by weight, of co-granules according to the first aspect
W0 95/20030 PCT/EP95/00226
23
of the invention. The co-granules used to form the
tablet are made by any of the processes described above.
The tablet of the invention preferably contains less than
35% by weight, preferably less than 20% by weight, of
irritant material selected from peroxygen bleach,
silicate, carbonate, protease and surfactant.
The strength of the tablet of the invention should
preferably be high enough to allow handling without the
need for individual wrapping.
The tablet strength is defined as the force, expressed in
Newtons, needed to break the tablet, as measured using a
Chatillon type UTSM (remote 500) instrument in a
direction perpendicular to the direction of compression.
The tablet-strength should preferably be at least about
150 Newton, more preferably at least about 200 Newton, so
as to be sufficient for the tablet concerned to survive
handling and packing. On the other hand, the tablet
strength should not be too high, since in such a case the
dissolution characteristics of the tablet concerned may
not be adequate. The tablet strength should generally be
below about 1000 Newton, preferably below about 800
Newton, more preferably below about 600 Newton, for round
tablets. For rectangular tablets, the tablet strength
should generally be below about 2000 Newton, preferably
below about 1600 Newton, more preferably below about 1400
Newton.
The tablets of the invention preferably have a density of
at least about 1300 kg/m3.
In order to achieve good cleaning performance, the
tablets of this aspect of the invention preferably
comprise more than about 20% by weight, preferably from
W O 95!20030 PCTIEP95100226
24
about 25 to about 50% by weight, of the salt of di-,
tri-, or tetracarboxylic acid, as builder salt.
In a preferred embodiment the detergent tablet of
this aspect of the present invention comprises (in
approximate amounts):
25-90 %wt of the cogranule material;
5-20 %wt of a hydrogen peroxide source selected from
alkali metal peroxides, organic peroxides, inorganic
persalts, and mixtures thereof;
0-5 %wt of a bleach catalyst;
0-10 %wt of enzyme material;
0-5 %wt of tabletting aids;
0-10 %wt of minor detergent ingredients.
It is usually advantageous if the bulk density and size
distribution of the bleach and enzyme components of the
tablet are comparable to that of the co-granule material.
The tablet of the invention may be effectively produced
by a process involving the steps of mixing the co-granule
material with the other ingredients of the tablet, and
compacting the resulting detergent mixture using a
pressure of at least 10 KN/cm2.
After having carried out the compaction step,
difficulties may be encountered in releasing the just
prepared tablet from the mould. These may be overcome by
incorporating a minor amount-(usually not more than 4% by
weight) of any of the well-known mould release agents
such as calcium stearate, talcum powder, siliconized
talcum, stearic acid or paraffins. In this,respect, it
may also be helpful to incorporate nonionic surfactant
into the tablet. Other suitable tablet-making aids which
may be incorporated include glidants and lubricants such
as sodium benzoate, fatty acids, fatty alcohols, starch
WO 95/20030 PCTIEP95I00226
and polyethylene glycol.
EXAMPLES
The invention will now be further illustrated by the
following non-limiting examples) All parts and
5 percentages mentioned are on a weight basis unless
indicated otherwise.
Examples 1 and 2 (Preparation of co-granules)
Slurries were prepared having the following composition:
Comnositio~n (gramsl
10 Example 1 ple 2
Alkaline silicate solution (45%*) 302 1209
Sodium hyroxide solution (46%*) 190 763
Citric acid solution (48%*j 292 1170
Copolymer maleate/acrylate (Sokalan 56 225
15 CP-5 ex BASF) solution (40%*)
Nonionic surfactant (Plurafac LF403) 8.5 -
Synthetic clay (Laponite powder) 8.5 34
(* aqueous solutions)
The slurries of Examples 1 and 2 had a water content of
20 55% (w/w), with a low viscosity.
The slurries were dried using a laboratory scale spray
tower, followed by restructing (milling and spraying-on
a few percent of a 45% alkaline silicate solution) and
redrying.
25 The co-granules so obtained showed an excellent whiteness
due to citrate which was translucent bound up in a white
co-granule. Moreover the co-granules were easily soluble
in water and showed an excellent dish washing
performance.
WO 95120030 PCT/EP95/00226
26
Examele 3 (Preparation of co-granules)
A slurry was prepared on a tonne scale having the ,
following composition by adding the ingredients one after
another:
parts per weight
Citric acid solution (48%*) 90
Sodium hydroxide solution (45%*) 58
Copolymer maleate/acrylate solution (40%*) 12.5
Alkaline silicate solution (45%*) 75.6
(* aqueous solutions)
The moisture content of the slurry was 55% (w/w). It had
a low viscosity. The slurry was dried using a pilot
scale spray tower, yielding a powder with a moisture
content of 12% (w/w), a bulk density of 40og/1 and an
average particle diameter of 400~Cm.
The powder was partly broken and restructured using a
Lodige recycler and plough share mixer, yielding co-
granules with a bulk density of 750 g/1 and an average
particle diameter of 550~Cm.
The appearance of the final product was pleasant. It
dissolved and dispensed well in automatic dishwashing
machines with a dissolution time of 1 minute at 20°C and
a dispensing time of 4 minutes at 20°C. When compared
with a product of the same composition obtained by dry
mixing of components, these data were 3 minutes and 10
minutes, respectively.
WO 95/20030 PCTIEP95100226
27
Example 4 (Preparation of tablets ~rom co-granules and
comparative testing thereof)
The strength of detergent tablets produced from a
detergent mixture not containing co-granules was compared
with the strength of tablets according to the invention
produced from a mixture having the same composition but
containing co-granules.
First, co-granules were prepared having the
following composition:
Composition !parts by weiyhtl
Example 4A Example 4B
Sodium citrate 40 30
Maleate/acrylate copolymer~l> 6 6
Sodium disilicate 26.2 5
Sodium bicarbonate 0 36.7
Note:
this is Sokalan CP-5 ex BASF
These co-granules were prepared by a method
comprising the following steps:
(1) preparing a slurry containing the constituents of the
co-granules concerned, and having a moisture content of
55% by weight and a low viscosity;
(2) drying the slurry using a pilot scale spray tower,
yielding a powder with a moisture content of 12% by
weight, a bulk density of 400 g/1 and an average particle
diameter of 400 microns;
(3) partly breaking and restructuring the powder using
a mill, and a L&dige recycler and plough share mixer,
yielding co-granules with a bulk density of 750 g/1 and
an average particle diameter of 550 microns.
W0 95/20030 PCTIEP95I00226
~t804~3
28
Subsequently, detergent tablets having a weight of 20
grams were made from mixtures containing the co-granules,
by compacting these mixtures using a Fette Perfecta 3
tabletting machine fitted with a 41 mm round die and
optionally plastic inserts. The compaction pressure was
30 kN/cm2.
Using the same compacting method, 20 gram tablets
(Comparative Examples 4C and 4D, respectively) were also
made from mixtures not containing these co-granules but
instead comprising the individual, non-co-granulated
constituents thereof at concentrations equal to their
respective concentrations in the co-granules-containing
mixtures.
The compositions of the mixtures from which the
tablets were produced were (in $ weight):
as follows by
Example
Example no ~ 4C 4~ gyp,
(Comparative ) (Comparative)
Co-granules 72.2 - 77.7 -
Sodium citrate~2> - 40 - 30
Acrylate/maleate - 6 - 6
copolymer
Sodium disilicate - 26.2 - ~ 5
Sodium bicarbonate - - - 36.7
perborate mono~3~ 18 18 16 16
Bleach catalyst 2.8 2.8 2.4 2.4
granules ~4~
Enzymes ~5) 5.4 5.4 3.3 3.3
Nonionic surfactant 1.5 1.5 - 1.5 1.5
(Plurafac LF403)
Perfume 0.1 0.1 0.1 0.1
W095/20030 ~ ~ ~ PCTIEP95100226
29
Note:
~2~ for the comparative Examples, granular sodium
citrate was used;
~3~ sodium perborate monohydrate;
~4> the composition oi: these granules was as follows:
sodium carbonate 85% wt, acrylate/maleate copolymer
(SOkalan) 5%wt, triazacyclononane based Mn-complex
catalyst (as described in EP-A-458,397) 3% wt, moisture
7% wt;
~5> Savinase and Termamyl in a weight ratio of 5:3, ex
NOVO.
The strength of the tablets produced was measured
using a Chatillon type VTSM (remote 500) instrument. The
measurement was carried out as defined hereinabove, i.e.
in a direction perpendicular to the direction of
compression. The following tablet strength values,
expressed in Newtons, were obtained:
Example no
(Comparative) (Comparative)
Tablet strength 808 45 448 115
It can be concluded that the tablets according to
the present invention have a considerably higher tablet
strength than those of the comparative Examples.
W0 95120030 PCT/EP95100226
The tablets of the invention took about 8 minutes to
dissolve during a dishwashing cycle in a Bauknecht GSF
1161 automatic dishwashing machine.
**********
