Note: Descriptions are shown in the official language in which they were submitted.
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PROCESS FOR PREPARING HIGH BULK DENSITY DETERGENT
COMPOSITIONS
FIELD OF THE INVENTION
The present invention relates to a process for
preparing a granular detergent composition or component by
mixing. More in particular, it relates to a process for the
continuous preparation of such detergent compositions.
Furthermore, it relates to a granular detergent composition
obtainable by the process of the present invention.
BACKGROUND OF THE INVENTION
Generally speaking, there are two main types of
processes by which detergent powders can be prepared. The
first type of process involves spray-drying and aqueous
detergent slurry in a spray-drying tower. In the second
type of process the various components are dry-mixed and
optionally agglomerated~with liquids, e.g. nonionics. The
latter kind of process is more suited to the production of
powders having a relatively high bulk density. That is
primarily because the chemical composition of the slurry
used in the spray drying process markedly, affects the bulk
density of the granular product. This bulk density can only
be significantly increased by increasing the content of
relatively dense sodium sulphate. However, sodium sulphate
does not contribute to detergency, so that the overall
performance of the powder in the wash is thereby reduced.
In the past few years, there have been several
proposals for mechanical mixing processes for the production
of high density detergent powders. For example EP-A-265 203
discloses liquid surfactant compositions which contain a
sodium or potassium salt of an alkylbenzene sulphonate or
alkyl sulphate, an ethoxylated nonionic surfactant and
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water. The amount of water does not exceed 10~ by weight.
Such liquid surfactant composition may be sprayed onto a
solid particulate absorbent material, for instance a porous
spray-dried base powder having a low bulk density and
containing little or no actives, to form a detergent base
powder having an increased bulk density.
EP-A-507 402 discloses a process for preparing a liquid
surfactant composition comprising an anionic surfactant, a
nonionic surfactant and having a relatively low water
content. The principle of the process is to neutralize the
acid corresponding to the anionic surfactant with a
neutralizing agent of a strength such as to lead to the
desired low level of water in the final product by adding
these two materials to a fluid which comprises the nonionic
surfactant and which acts as a solvent or diluent for the
neutralized anionic surfactant. This process is carried out
continuously, preferably in a loop reactor.
EP-A-420 317 discloses a process for the continuous
preparation of granular detergent compositions or components
having a higher density than is achievable in spray drying
processes. The process consists of three steps, an
agglomeration in a high-speed mixer, a densification in a
moderate-speed granulator densifier whereby the material is
brought or maintained in a deformable state, and the drying
and/or cooling of the product ~e.g. in a fluid bed). A
liquid acid precursor of an anionic surfactant is in situ
neutralized by a solid water-soluble alkaline inorganic
material (e. g. sodium carbonate) in the high-speed mixer.
The deformable state of the material at temperatures above
40QC is obtained at least partially by the heat of
neutralization of the acid.
EP-A-544 365 discloses a process for the preparation of
a granular composition in the same equipment described in EP
0 420 317 or alternative in a batch granulation. In this
case a mixture of a sodium or potassium salt of an alkyl
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sulphate e.g. a primary alkyl sulphate and an alkyoxylated
nonionic surfactant is used as the liquid phase for the
granulation in the high speed mixer. For obtaining
y detergent powders with good powder properties the
agglomeration process is controlled by a significant
increase of the liquid viscosity. This is obtained by the
addition of one or more components to the liquid surfactant
composition. Examples of such viscosity raising components
are water and fatty acid in combination with stoichiometric
amount of alkaline material (e. g. caustic soda) sufficient
to neutralize the fatty acid which results in the formation
of soap.
When the powder is to be formulated to contain a
phosphate detergency builder such as sodium
tripolyphosphate, the known mixing processes have a number
of drawbacks which are deleterious to the requirement to
produce free-flowing powders with good granularity and low
moisture content. These in part are probably attributable
to the low liquid carrying capacity of the phosphate builder
particles. Typical problems which can be encountered
include the build-up of hard lumps due to brisk exothermic
hydration and crystal bridge formation. Moreover, soft
granules tend to be formed in the resultant product with
poor powder behaviour due to the low adhesive forces of the
wet particle surfaces and hence, poor granule structure.
A. Naviglio and A. Moriconi ("Detergents Manufacture -
A new, low cost, energy-saving, cool and dry process",
Soap/Cosmetics/Chemical Specialities, Sept. 1987) describe a
continuous process with a turbo reactor and a rotating drum
agglomerator for the preparation of granular detergent
compositions. The dry neutralisation reaction takes place
in the turbo reactor into which the solids are dosed at the
. same time (e. g. solids: STP, alkaline powder (e. g. sodium
carbonate); liquids: caustic solution, LAS acid, fatty
acid). The mixing in the turbo reactor is achieved by
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special air diffusers which keep the powders and the liquids
suspended. Cooled air is used to eliminate the reaction
heat. The reactor contains a screw for continuous conveying
to the agglomeration step. The agglomeration is provided by
spraying on sodium silicate or nonionics in the rotating
drum. This process provides a separation of the
neutralisationlhydration and the agglomerisation. Formation
of large lumps of hydrated STP might be prevented by the
suspension with an air stream. Due to the low absorption
capacity of STP the spraying on of nonionics is not suitable
for preparing detergent powders with a high content of
actives.
SUMMARY OF THE INtIENTION
The problems related to the inclusion of STP or other
solids having a low liquid-carrying capacity and/or
hydratable properties have, however, now been overcome by a
new but simpler process which can be effected using reactor
and mixer equipment which is already conventional in the
art. However, it also has advantages in the processing of
other kinds of solids. This new process constitutes the
present invention and formulating a liquid component with a
structurant so ws to remain pumpable at the temperature at
which the liquid component is formed and then admixing it
with a solid component at a lower temperature at which the
structurant causes solidification of the mixture.
WO 95/32276 discloses a process in which "liquid"
components are formulated as a (preferably aqueous) paste
having a viscosity of between 5 and 100 Pas at 70°C and
then granulated with a solid component. However, this
process does not disclose use with phosphate builders or
other inorganic salts with similar liquid carrying and/or
hydration properties and so the problems solved by the
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present invention are not addressed. Moreover, it doss nqt
provide the convenience of being able to pump the liquid
component and the solution to providing low relative
humidity products is also not addressed: For example, the
process of the present invention also produces unexpected
benefits with different detergency builders such as
zeolites, enabling the manufacture of granular products with
a lower relative humidity without drying than hitherto.
This low humidity allows percarbonate bleaches to be post
dosed, these being preferred over perborates on
environmental grounds.
The resultant granulated product which when tabletted,
produces tablets having a high degree of hardness as
measured by break strength (PmeX) and E modulus (E",~). These
parameters can optionally be used also to characterise the
solidified blend in the granulator.
Thus, in a first aspect, the present invention provides a
process for preparing a granular detergent composition, the
ZO process comprising a first step of preparing a liquid component
which comprises a structurant and from 98o to 10o by weight of
that component of anionic surfactant, a second step of admixture
of the liquid component with a solid component in a granulator,
and optionally, a third step which comprises at least one of
drying and cooling, the structurant being incorporated in an
amount such that the liquid component is pumpable at a
temperature of 75°C and is solid at 25°C and causes sufficient
solidification during at least one of the second and third steps
to form a free-flowing granulated product.
In a second aspect, the invention provides a granular
detergent composition or component prepared by this process.
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N ~
10
20
The granular product so prepared can be considered to
be free flowing if it has a dynamic flow rate (DFR) of
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measured by a technique whereby known volume of powder is
permitted to flow through a calibrated orifice and tube.
The flow time between two light sensors is automatically
recorded and the DFR is calculated with the known volume and
the recorded flow time.
Granular detergent compositions according to the
present invention may be in the form of complete products
ready for sale to the consumer. Alternatively, they may be
formulated as base powders or adjuncts for admixture with
other ingredients. In any event such compositions may have
a bulk density of 550 g/1, more preferably at least &50 g/1.
However, these products may also be produced with lower bulk
densities.
Preferred embodiments of process and compositions
according to the present invention may be characterised by
the strength and E-modulus of a sample of
(a) tabletted composition produced by the process; and/or
(b) tablet formed by cooling of the liquid component until
it solidifies.
The strength (hardness) measurement can be obtained
using an Instron pressure apparatus. The powder is
tabletted in a punch and die to form a tablet 9 mm in
diameter and 16 mm in height, formed by exerting a maximum
pressure of 10 tons on the tablet surface. In the case of a
solidified liquid component taken from the process before it
contacts the solid component, the tablet diameter is 14 mm
and its height is 19 mm.
The tablet (powder or liquid component) is destroyed
between a fixed and a moving plate. The speed of the moving
plate is set to 5 mm/min, which causes a measuring time of
about 2 sec. The pressure curve is logged on a computer.
Thus, the maximum pressure (at the moment of tablet
breaking) is given and the E-modulus is calculated from the
slope.
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For the granular product, the minimum value of PmeX is
preferably 0.5 M Pa, most preferably 2 M Pa and the minimum
value of Emod is preferably 20 M Pa, most preferably 50 M Pa.
However, for the solidified liquid component, PmeX at 20°C is
preferably a minimum of 0.2 M Pa, e.g. from 0.3 to 0.5 M Pa.
At 55QC, a typical range is from 0.05 to 0.25 M Pa. At
20°C, Emoa for the blend is preferably a minimum of 3 M Pa,
e.g. from 5 to 10 M Pa.
The liquid component is preferably prepared in a shear
dynamic mixer for premixing the components thereof and
performing any neutralisation of anionic acid precursor.
The dynamic mixer is preferably located in a loop with a
heat exchange to remove the heat of reaction of such
neutralisation.
In the context of the present invention, the term
"structurant" means any component which enables the liquid
component to achieve solidification in the granulator and
hence good granulation, even if the solid component has a
low liquid carrying capacity.
Structurants may be categorised as those believed to
exert their structuring (solidifying) effect by one of the
following mechanisms, namely: recrystalisation (e. g.
silicate or phosphates); creation of a network of finely
divided solid particles (e. g. silicas or clays); and those
which exert steric effects at the molecular level (e. g.
soaps or polymers) such as those types commonly used as
detergency builders. One or more structurants may be used.
Soaps represent one preferred class of structurant,
especially when the liquid component comprises a liquid
nonionic surfactant. In many cases it may be desirable for
the soap to have an average chain length greater than the
average chain length of the liquid nonionic surfactant but
less than twice the average chain length of the latter.
If desired, solid components may be dissolved or
dispersed in the liquid component. Typical amounts of the
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essential components of the ingredients of the liquid phase
are as follows.
Preferably from 10% to 98% by weight of the
substantially liquid component comprises liquid nonionic
surfactant, more preferably from 30% to 70% by weight and
especially from 40% to 50% by weight; and preferably from
98% to 10 by weight of the anionic surfactant, more
preferably from 70% to 30% and especially from 50% to 40% by
weight. The total amount of structurant is preferably from
2% to 30% by weight of the liquid component, more preferably
from 5% to 20% or 5% to 15% by weight and especially from
10% to 15% by weight. It is generally preferred talthough
not absolutely mandatory) for the liquid component to
comprise at least some liquid nonionic surfactant. However,
in general, other organic solvents may be used instead of or
in addition to the liquid nonionic.
The liquid component is also preferably substantially
non-aqueous. That is to say, the total amount of water
therein is not more than 15% by weight of the liquid phase,
preferably not more than 10% by weight, typically from 5% to
8%, especially from 6% to 7%.
Typically, from 3% to 4% by weight of the liquid
component may be water as the reaction by-product and the
rest of the water present will~be the solvent in which the
alkaline material was dissolved. The liquid phase is very
preferably devoid of all water other than that from the
latter-mentioned sources, except perhaps for trace
amounts/impurities.
It is very much preferred to form some or all of any
anionic surfactant in situ in the liquid component by
reaction of an appropriate acid precursor and an alkaline
material such as an alkali metal hydroxide, e.g. NaOH.
Since the latter normally must be dosed as an aqueous
solution, that inevitably incorporates some water.
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Moreover, the reaction of an alkali metal hydroxide and acid
precursor also yields some water as a by-product.
However, in principle, any alkaline inorganic material
can be used for the neutralisation but water-soluble
alkaline inorganic materials are preferred. Another
preferred material is sodium carbonate, alone or in
combination with one or more other water-soluble inorganic
materials, for example, sodium bicarbonate or silicate. As
alluded to above, sodium carbonate can provide the necessary
alkalinity for the wash process, but it can additionally
serve as a detergency builder. In this case the invention
may be advantageously used for the preparation of detergent
powders in which sodium carbonate is the sole or principal
builder. Then, substantially more carbonate will be present
than required for the neutralization reaction with the acid
anionic surfactant precursor.
The liquid component may optionally comprise dissolved
solids and/or finely divided solids which are dispersed
therein. The only limitation is that with or without
dissolved or dispersed solids, the liquid component should
be pumpable at temperatures of 50~C or greater or at any
rate, 60°C or greater e.g. 75°C. Preferably it is solid at
below 50~C, preferably at 25~C or less. Generally speaking,
pumpable liquid components have a viscosity no greater than
1 Pa at the shear rate of the pumping. The structurants
cause solidification in the blender preferably to produce
blend and tablet strength as described hereinbefore.
Typically, the temperature in the granulation is more than
10°C, preferably more than 20~C below the temperature at
which the blend is prepared and pumped into the granulator.
If the solid component comprises or substantially
consists of a phosphate builder the weight ratio of liquid
component to the solid component when the two are brought
into contact for mixing is from 0.25:1 to 0.5:1. If the
solid component comprises or substantially consists of an
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aluminosilicate builder, this ratio is preferably from 0.4:1
to 0.7:1.
Suitable anionic surfactants are well-known to those
skilled in the art. Examples suitable for incorporation in
the liquid phase include alkylbenzene sulphonates,
particularly linear alkylbenzene sulphonates having an alkyl
chain length of C8-C15; primary and secondary alkyl
sulphates, particularly C12-C15 primary alkyl sulphates;
alkyl ether sulphates; olefin sulphonates; alkyl xylene
sulphonates; dialkyl sulphosuccinates; and fatty acid ester
sulphonates. Sodium salts are generally preferred.
The nonionic surfactant component of the liquid phase
may be any one or more liquid nonionics selected from
primary and secondary alcohol ethoxylates, especially CB-Czo
aliphatic alcohols ethoxylated with an average of from 1 to
moles ethylene oxide per mole of alcohol, and more
especially the Clo-Cks primary and secondary aliphatic
alcohols ethoxylated with an average of from 1 to 10 moles
of ethylene oxide per mole of alcohol. Non-ethoxylated
20 nonionic surfactants include alkylpolyglycosides, glycerol
monoethers, and polyhydroxyamides (glucamide).
The liquid acid precursor may be selected from linear
alkyl benzene sulphonic acids, alphaolefin sulphonic acids,
internal olefin sulphonic acids, fatty acid ester sulphonic
acids and combinations thereof. The process of the
invention is especially useful for producing compositions
comprising alkyl benzene sulphonates by reaction of the
corresponding alkyl benzene sulphonic acid, for instance
Dobanoic acid ex Shell.
Linear or branched primary alkyl sulphates having 10 to 15
carbon atoms can also be used.
The solid component with which the liquid phase is
admixed preferably comprises a detergency builder. The
total amount of detergency builder in the final compositions
is suitably from 10 to 80 wto, preferably from 15 to 60 wt~.
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The builder may be present in an adjunct with other
components or, if desired, separate builder particles
containing one or more builder materials may be employed.
The present invention is especially applicable to use
where the solid component comprises hydratable salts,
preferably in substantial amounts such as at least 25~ by
weight of the solid component, preferably at least 10~ by
weight. Hydratable solids include inorganic sulphates and
carbonates, as well as inorganic phosphate builders, for
example, sodium orthophosphate, pyrophosphate and
tripolyphosphate,
Other suitable builders include crystalline and
amorphous aluminosilicates, for example zeolites as
disclosed in GB-A-1 473 201; amorphous aluminosilicates as
disclosed in GB-A-1 473 202; and mixed crystalline/amorphous
aluminosilicates as disclosed in GB 1 470 250; and layered
silicates as disclosed in EP-B-164 514.
Aluminosilicates, may suitably be present in a total
amount of from 10 to 60 wto and preferably an amount of from
15 to 50 wt~. The zeolite used in most commercial
particulate detergent compositions is zeolite A.
Advantageously, however, maximum aluminium zeolite P
(zeolite MAP) described and claimed in EP-A-384 070 may be
used. Zeolite MAP is an alkali metal aluminosilicated of
the P type having a silicon to aluminium ratio not exceeding
1.33, preferably not exceeding 1.15, and more preferably not
exceeding 1.07.
Other inorganic builders that may be present include
sodium carbonate (as mentioned above, an example of a
hydratable solid), if desired in combination with a
crystallisation seed for calcium carbonate as disclosed in
GB-A-1 437 950. As mentioned above, such sodium carbonate
may be the residue of an inorganic alkaline neutralising
agent used to form a nonionic structurant i~ situ.
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Organic builders that may be present include
polycarboxylate polymers such as polyacrylates,
acrylic/maleic copolymers, and acrylic phosphinates;
monomeric polycarboxylates such as citrates, gluconates,
oxydisuccinates, glycerol mono-, di- and trisuccinates,
carboxymethyloxysuccinates, carboxymethyloxymalonates,
dipicolinates, hydroxyethyliminodiacetates,
aminopolycarboxylates such as nitrilotriacetates (NTA),
ethylenediaminetetraacetate (EDTA) and iminodiacetates,
alkyl- and alkenylmalonates and succinates; and sulphonated
fatty acid salts. A copolymer of malefic acid, acrylic acid
and vinyl acetate is especially preferred as it is
biodegradable and thus environmentally desirable. This list
is not intended to be exhaustive.
Especially preferred organic builders are citrates,
suitably used in amounts of from 5 to 30 wt%, preferably
from 10 to 25 wt%; and acrylic polymers, more especially
acrylic/maleic copolymers, suitably used in amounts of from
0.5 to 15 wt%, preferably from 1 to 10 wt%. The builder is
preferably present in alkali metal salt, especially sodium
salt, form.
Granular detergent compositions of the invention may
contain, in addition to the nonionic and ionic surfactants
of the liquid blend, one or more other detergent-active
compounds (surfactants) which may be chosen from soap and
non-soap anionic cationic, nonionic, amphoteric and
zwitterionic detergent-active compounds, and mixtures
thereof. These may be dosed at any appropriate stage before
or during the process. Many suitable detergent-active
compounds are available and are fully described in the
literature, for example, in "Surface-Active Agents and
Detergents", Volumes I and II, by Schwartz, Perry and Berch.
The preferred detergent-active compounds that can be used
are soaps and synthetic non-soap anionic and nonionic
compounds.
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Detergent compositions according to the invention may
also contain a bleach system, desirably a peroxy bleach
compound, for example, an inorganic persalt or organic
peroxyacid, capable of yielding hydrogen peroxide in aqueous
'5 solution. The peroxy bleach compound may be used in
conjunction with a bleach activator (bleach precursor) to
improve bleaching action at low wash temperatures. An
especially preferred bleach system comprises a peroxy bleach
compound (preferably sodium percarbonate optionally together
with a bleach activator), and a transition metal bleach
catalyst as described and claimed in EP 458 397A and EP-A-
509 787.
Usually, any bleach and other sensitive ingredients
such as enzymes and perfumes will be post-dosed after
granulation as will be minor ingredients.
Typical minor ingredients include sodium silicate;
corrosion inhibitors including silicates; antiredeposition
agents such as cellulosic polymers; fluorescers; inorganic
salts such as sodium sulphate, lather control agents or
lather boosters as appropriate; proteolytic and lipolytic
enzymes; dyes; coloured speckles; perfumes; foam
controllers; and fabric softening compounds. This list is
not intended to be exhaustive.
Powder flow may be improved by the incorporation of a
small amount of an additional powder structurant, for
example, a fatty acid (or fatty~acid soap), a sugar, an
acrylate or acrylate/maleate polymer, or sodium silicate
which is suitably present in an amount of from 1 to 5 wt~.
Regarding the equipment used for the mixing stages) of
the process (i.e. after admixture of the liquid and solid
components), the liquid component is preferably admixed with
the solid components in a first mixing step in a high-speed
mixer/densifier to form a granular detergent material.
Optionally, the granular detergent material from the first
mixing step may subsequently be treated in a second mixing
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step in a moderate-speed granulator/densifier. If high bulk
density product is desired, at this stage it can be brought
into or maintained in the required deformable state. In any
event, the product of the first mixing step or the second
mixing step may then be cooled and/or dried.
The residence time in the high-speed mixer/densifier in
the first mixing step is preferably from about 5 to 30
seconds. The residence time in the moderate-speed
mixer/densifier during any second (optional) mixing step is
preferably from about 1 to 10 minutes. It is preferred to
perform any such process as a continuous process but it
could be performed as a batch process in a high shear or low
shear mode.
In the first mixing step, the solid components of the
feedstock are very thoroughly mixed with the liquid blend by
means of a high-speed mixer/densifier. Such a mixer
provides a high energy stirring input and achieves thorough
mixing in a very short time.
As high-speed mixer/densifier we advantageously used
the Lodige (Trade Mark) CB 30 Recycler. This apparatus
essentially consists of a large, static hollow cylinder
having a diameter of about 30 cm which is horizontally
placed. In the middle, it has a rotating shaft with several
different types of blades mounted thereon. It can be
rotated at speeds between 100 and 2500 rpm, dependent on the
degree of densification and the particle size desired. The
blades on the shaft provide a thorough mixing action of the
solids and the liquids which may be admixed at this stage.
The mean residence time is somewhat dependent on the
rotational speed of the shaft, the position of the blades
and the weir at the exit opening.
Other types of high-speed mixers/densifiers having a
comparable effect on detergent powders can also be
contemplated. For instance, a Shugi (Trade Mark) Granulator
or a Drais (Trade Mark) K-TTP 80 may be used.
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In the first mixing step, the components of the
feedstock are thoroughly mixed in a high-speed
mixer/densifier for a relatively short time of about 5-30
seconds, preferably under conditions whereby the starting
material is brought into, or maintained in, a deformable
state, to be defined hereafter.
In the case of production of high bulk density
products, after the first mixing step, if the resultant
detergent material still possesses a considerable porosity,
then instead of choosing a longer residence time in the
high-speed mixer/densifier to obtain a further bulk density
increase, it may then be subjected to the optional second
mixing step in which the detergent material is treated for
1-10 minutes, preferably for 2-5 minutes, in a moderate-
speed granulator/densifier. During this second processing
step, the conditions are such that the powder is brought
into, or maintained in, a deformable state. As a
consequence, the particle porosity will be further reduced.
The main differences with the first step reside in the lower
mixing speed and the longer residence time of 1-10 minutes,
and the necessity for the powder to be deformable.
The optional second mixing step can be successfully
carried out in a Lodige (Trade Mark) KM 300 mixer, also
referred to as Lodige Ploughshare. This apparatus
essentially consists of a hollow static cylinder having a
rotating shaft in the middle. On this shaft various plough-
shaped blades are mounted. It can be rotated at a speed of
40-160 rpm. Optionally, one or more high-speed cutters can
be used to prevent excessive agglomeration. Another
suitable machine for this step is, for example the Drais
(Trade Mark) K-T 160.
However, instead of using a high-speed mixer densifier
machine, followed by a separate moderate speed-mixer
densifier machine, the same effect could be obtained using a
single machine operated at two speeds. It could be operated
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first at high speed for mixing/densification and then at
moderate speed for granulation/densification. Suitable
machines include mixers of the FukaeR FS-G series; DiosnaR V
series ex Dierks & Sohne, Germany; Pharma MatrixR ex T.K.
~5 Fielder Ltd; England; FujiR VG-C series ex Fuji Sangyo Co.,
,7apan; the RotoR ex Zanchetta & Co. srl, Italy and the
SchugiR Flexomix granulator.
For use, handling and storage, the densified detergent
powder must be in a free flowing state. Therefore, in a
final step the powder can be dried and/or cooled if
necessary. This step can be carried out in a known manner,
for instance in a fluid bed apparatus (drying, cooling) or
in an airlift (cooling). It is advantageous if the powder
needs a cooling step only, because the required equipment is
relatively simple and more economical.
For production of high bulk density products, any
optional second mixing step and preferably also for the
first mixing step, the detergent powder should be brought
into a deformable state in order to get optimal
densification. The high-speed mixer/densifier and/or the
moderate speed granulator/densifier are then able to
effectively deform the particulate material in such a way
that the particle porosity is considerably reduced or kept
at a low level, and consequently the bulk,density is
increased.
The invention will now be explained in more detail by
way of the following non-limiting examples.
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EXAMPLES
1. Granulation of STP:
Preparation of the blend in the loop-reactor with
LAS acid: 69.4 kg/h
Premix Nonionic
surfactant/Fatty acid
Nonionic surfactant 7 EO 58.9 kg/h
Nonionic surfactant 3 EO 31.7 kg/h
Fatty acid ~C16-C18 17.7 kg/h
Neutralisation with caustic soda to pH 11:
NaOH-solution (50%): 22.3 kg/h
This blend (200 kg/h, water content - 10%) was used for the
granulation of 600kg/h STP in the recycler (Loedige CB30).
2. Granulation of STP, Sulphate and Carbonate:
Preparation of the blend in a loop-reactor with
LAS acid: 74.7 kg/h
Neutralisation of the LAS acid with caustic soda:
NaOH-solution (50%): 18.4 kg/h
Alkaline silicate solution(45%): 38.1 kg/h
Neutralisation of the alkalinity with a premix of
nonionic surfactant/fatty acid:
Nonionic surfactant 7 EO 63.3 kg/h
Nonionic surfactant 3 EO: 34.1 kg/h
Fatty acid C16-C18: 17.1 kg/h
This blend (245.6 kg/h, water content = 13.2%) was used for
the granulation of the following powders in the recycler
(Loedige CB30):
STP: 700 kg/h
Sulphate: 350 kg/h
Carbonate: 100 kg/h
CA 02263506 1999-02-16
WO 98/11198 PCT/EP97/04749
- 18 -
In the light of this disclosure, modifications of the
described examples, as well as other examples, all within
the scope of the present invention as defined by the
appended claims will now become apparent to persons skilled
in the art.
