Note: Descriptions are shown in the official language in which they were submitted.
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PROCESS FOR CONDITIONING OF SURFACTANT PASTES TO FORM HIGH
ACTIVE SURFACTANT AGGLOMERATES
The invention relates to a process for making a granular
detergent component or composition.
Manufacturing processes are known wherein granular
detergent products are made by forming a neutral or
alkaline paste comprising at least 40% by weight of anionic
surfactant; and mixing the high viscosity paste so-formed
with builder powders wherein the ratio of high viscosity
paste to builder powder is from 9:1 to 1:5 to form the
granular detergent component or composition. Such processes
are commonly called agglomeration processes
EP-A-0 663 439, published on 19th July 1995, and EP-A-0 508
543, published on 14th Oct., 1992, both describe enhanced
embodiments of agglomeration processes which includes a
process of surfactant paste conditioning in, for example, a
twin-screw extruder, followed by granulation in a high
shear mixer.
EP-A-0 508 543 mentions the possibility to add anionic
surfactant into the process via a powder stream. However it
is not specified whether this powder stream is added into
the extruder, or into the high-shear mixer. Neither of
these publications describes the use of dry alkyl sulphate
powder in the conditioning step.
The object of the present invention is to provide an
effective process for conditioning pastes comprising at
least 40% by weight of anionic surfactant. The conditioning
agent disrupts surfactant crystallinity, and also increases
the viscoelasticity of the paste. The crystalline
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disruption improves rate of surfactant solubility, whilst the
viscoelasticity increase "conditions" the paste enabling
agglomerates with high surfactant activity to be formed. The
paste is processed into agglomerates by granulating with
builder powders wherein the ratio of high viscosity paste to
builder powder is from 9:1 to 1:5.
Summary of the Invention
The object is achieved by mixing a first powder with the
surfactant paste in a ratio of at least 1 part powder to 100
parts paste, the first powder comprising at least 80o by
weight of alkyl sulphate, and whereby the mixing step
increases the viscosity of the surfactant paste.
In one particular embodiment there is provided a process for
making a granular detergent component or composition
comprising the steps of: (i) forming a neutral or alkaline
paste comprising at least 40o by weight of anionic surfactant;
(ii) mixing a first powder with the surfactant paste at a
temperature less then 100°C, in a ratio of at least 1 part
powder to 100 parts paste, and whereby the mixing step
increases the viscosity of the surfactant paste, from about
5,000 cps to 10,000,000 cps; (iii) forming the granular
detergent component or composition at a temperature from about
25°C to about 60°C, by mixing the high viscosity paste so-
formed with builder powders selected from the group consisting
of carbonate, aluminosilicate, silicate, and mixtures thereof,
wherein the ratio of high viscosity paste to builder powder is
from 9:1 to 1:5, having a bulk density of from about 0.4 to
about 1.2 g/cc, characterised in that the first powder
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comprises at least 80o by weight of alkyl sulphate wherein the
alkyl sulphate, comprises less than 5o by weight of water.
In a preferred embodiment of the invention, alkyl sulphate
powder, comprising less than 5o by weight of water, is mixed
with other surfactants in the paste in an extruder. In an even
more preferred embodiment of the invention the paste and alkyl
sulphate powder mixture is carried out sequentially in a high-
shear mixer granulator having a tool tip-speed of from 5 to
50 m/sec, and a medium speed agglomerator.
Most preferred builder powders are carbonate, aluminosilicate
and silicate.
Detailed Description of the Invention
The present invention concerns conditioning of anionic
surfactant in an aqueous, highly concentrated solution of
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its salt, preferably its sodium salt. These high active,
low moisture surfactant pastes are of a high viscosity but
remain pumpable at temperatures at which the surfactants
are stable. In other processes, anionic surfactants or
mixtures comprising at least one anionic surfactant, where
highly viscous liquid crystal phases occur, requires that
either lower viscous crystal phases be formed or that some
viscosity modifiers are used. This requires expensive
additives, and prevents high surfactant activities from
being achieved.
Conditioning of a paste means the modifying of its physical
characteristics to form higher active, less sticky
agglomerates which are not easily obtainable under normal
operating conditions. Conditioning of the paste as defined
herein, means: a) increasing its apparent viscosity, b)
increasing its effective melting point, c) increasing the
"hardness" of the paste. The hardness/softness of the paste
may be measured by a softness penetrometer according to
ASTM D 217-IP50 or ISO 2137. The hardness of conditioned
paste measured in this way should be less than 2cm,
preferably less than lcm.
Chemical conditioning agents are compounds that alter the
physical structure and/or physical characteristics of the
surfactant paste when added to the paste. In the present
invention the chemical conditioning agent is alkyl sulphate
in powdered form. It has been found that the addition to
the surfactant paste reduces the stickiness of the paste,
increases its viscosity and increases its softening point.
This allows for more paste to be added during the
agglomeration process thus leading to higher active
agglomerates, preferably between 40% and 60%, more
preferably greater than 50%. This method of treating the
surfactant paste can be performed batchwise and continuous,
preferably continuously.
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Alkyl sulphate powder is defined herein as any free-flowing
powder, flakes, noodles or needles which comprises at least
80o by weight of alkyl sulphate. Useful powders are
commercially available from Albright & Wilson, Hickson
Manro and Sidobre Sinnova. Alternatively suitable powders
may be prepared by sulphating an alcohol, followed by
neutralisation with, for example aqueous sodium hydroxide,
then drying in a suitable spray drying tower, wiped film
evaporator or suitable dryer. Dry neutralisation methods
may also be used, neutralising alkyl sulphuric acid with,
for example powdered sodium carbonate.
In a preferred embodiment of the invention an extruder is
used to condition the paste. The extruder is a versatile
piece of equipment which enables two or more pastes and the
alkyl sulphate powder to be mixed .
Process aids may also be used. Preferred process aids which
may be mixed with the surfactant paste are starch, soap,
fatty acids and polymers. Process aids and surfactant paste
may be mixed prior to the extruder in, for example, a high
shear mixer; or in the extruder itself.
The Pastes
One or various aqueous pastes of the salts of anionic
surfactants is preferred for use in the present invention,
preferably the sodium salt of the anionic surfactant. In a
preferred embodiment, the anionic surfactant is preferably
as concentrated as possible, (that is, with the lowest
possible moisture content that allows it to flow in the
manner of a liquid) so that it can be pumped at
temperatures at which it remains stable. While granulation
using various pure or mixed surfactants is known, for the
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present invention to be of practical use in industry and to
result in particles of adequate physical properties to be
incorporated into granular detergents, an anionic
surfactant must be part of the paste in a concentration of
above 40°s, preferably from 40-95%.
It is preferred that the moisture in the surfactant
aqueous paste is as low as possible, while maintaining
paste fluidity, since low moisture leads to a higher
concentration of the surfactant in the finished particle.
Preferably the paste contains between 5 and 40% water, more
preferably between 5 and 30% water and most preferably
between 5% and 20% water.
It is preferable to use high active surfactant pastes
to minimize the total water level in the system during
mixing, granulating and drying. Lower water levels allow
for: (1) a higher active surfactant to builder ratio, e.g.,
1:1; (2) higher levels of other liquids in the formula
without causing dough or granular stickiness; (3) less
cooling, due to higher allowable granulation temperatures;
and (4) less granular drying to meet final moisture limits.
Two important parameters of the surfactant pastes
which can affect the mixing and granulation step are the
paste temperature and viscosity. Viscosity is a function,
among others, of concentration and temperature, with a
range in this application from about 5,000 cps to
10,000,000 cps. Preferably, the viscosity of the paste
entering the system is from about 20,000 to about 100,000
cps. and more preferably from about 30,000 to about 70,000
cps. The viscosity of the paste of this invention is
measured at a temperature of 70°C.
The paste can be introduced into the mixer at an
initial temperature between its softening point (generally
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in the range of 40-60°C) and its degradation point
(depending on the chemical nature of the paste, e.g. alkyl
sulphate pastes tend to degrade above 75-85°C). High
temperatures reduce viscosity simplifying the pumping of
the paste but result in lower active agglomerates. In the
present invention, the activity of the agglomerates is
maintained high due to the elimination of moisture.
The introduction of the paste into the mixer can be
done in many ways, from simply pouring to high pressure
pumping through small holes at the end of the pipe, before
the entrance to the mixer. While all these ways are viable
to manufacture agglomerates with good physical properties,
it has been found that in a preferred embodiment of the
present invention the extrusion of the paste results in a
better distribution in the mixer which improves the yield
of particles with the desired size. The use of high
pumping pressures prior to the entrance in the mixer
results in an increased activity in the final agglomerates.
By combining both effects, and introducing the paste
through holes (extrusion) small enough to allow the desired
flow rate but that keep the pumping pressure to a maximum
feasible in the system, highly advantageous results are
achieved.
Hicrh Active Surfactant Paste
The activity of the aqueous surfactant paste is at
least 40% and can go up to about 95%; preferred activities
are . 50-80% and 65-75°s. The balance of the paste is
primarily water but can include a processing aid such as a
nonionic surfactant. At the higher active concentrations,
little or no builder is required for cold granulation of
the paste. The resultant concentrated surfactant granules
can be added to dry builders or powders or used in
conventional agglomeration operations. The aqueous
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surfactant paste contains an organic surfactant selected
from the group consisting of anionic, zwitterionic,
ampholytic and cationic surfactants, and mixtures thereof.
Anionic surfactants are preferred. Nonionic surfactants
are used as secondary surfactants or processing aids and
are not included herein as an "active" surfactant.
Surfactants useful herein are listed in U.S. Pat. No.
3,664,961, Norris, issued May 23, 1972, and in U.S. Pat.
No. 3,919,678, Laughlin et al., issued Dec. 30, 1975.
Useful cationic surfactants also include those described in
U.S. Pat. No. 4,222,905, Cockrell, issued Sept. 16, 1980,
and in U.S. Pat. 4,239,659, Murphy, issued Dec. 16, 1980.
However, cationic surfactants are generally less compatible
with the aluminosilicate materials herein, and thus are
preferably used at low levels, if at all, in the present
compositions. The following are representative examples of
surfactants useful in the present compositions.
Water-soluble salts of the higher fatty acids, i.e.,
"soaps", are useful anionic surfactants in the compositions
herein. This includes alkali metal soaps such as the
sodium, potassium, ammonium, and alkylammonium salts of
higher fatty acids containing from about 8 to about 24
carbon atoms, and preferably from about 12 to about 18
carbon atoms. Soaps can be made by direct saponification
of fats and oils or by the neutralization of free fatty
acids. Particularly useful are the sodium and potassium
salts of the mixtures of fatty acids derived from coconut
oil and tallow, i.e., sodium or potassium tallow and
coconut soap.
Useful anionic surfactants also include the water-
soluble salts, preferably the alkali metal, ammonium and
alkylolammonium salts, of organic sulfuric reaction
products having in their molecular structure an alkyl group
containing from about 10 to about 20 carbon atoms and a
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sulfonic acid or sulfuric acid ester group. (Included in
the term "alkyl" is the alkyl portion of acyl groups.)
Examples of this group of synthetic surfactants are the
sodium and potassium alkyl sulfates, especially those
obtained by sulfating the higher alcohols (C8-C18 carbon
atoms) such as those produced by reducing the glycerides of
tallow or coconut oil; and the sodium and potassium alkyl
benzene sulfonates in which the alkyl group contains from
about 9 to about 15 carbon atoms, in straight or branched
chain configuration, e.g., those of the type described in
U.S. Pat. Nos. 2,220,099 and 2,477,383. Especially
valuable are linear straight chain alkyl benzene sulfonates
in which the average number of carbon atoms in the alkyl
group is from about 11 to 13, abbreviated as C11-C13 ~S-
Other anionic surfactants herein are the sodium alkyl
glyceryl ether sulfonates, especially those ethers of
higher alcohols derived from tallow and coconut oil; sodium
coconut oil fatty acid monoglyceride sulfonates and
sulfates; sodium or potassium salts of alkyl phenol
ethylene oxide ether sulfates containing from about 1 to
about 10 units of ethylene oxide per molecule and wherein
the alkyl groups contain from about 8 to about 12 carbon
atoms; and sodium or potassium salts of alkyl ethylene
oxide ether sulfates containing from about 1 to about 10
units of ethylene oxide per molecule and wherein the alkyl
group contains from about 10 to about 20 carbon atoms.
Other useful anionic surfactants herein include the
water-soluble salts of esters of alpha-sulfonated fatty
acids containing from about 6 to 20 carbon atoms in the
fatty acid group and from about 1 to 10 carbon atoms in the
ester group; water-soluble salts of 2-acyloxy-alkane-1-
sulfonic acids containing from about 2 to 9 carbon atoms in
the acyl group and from about 9 to about 23 carbon atoms in
the alkane moiety; alkyl ether sulfates containing from
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about 10 to 20 carbon atoms in the alkyl group and from
about 1 to 30 moles of ethylene oxide; watersoluble salts
of olefin sulfonates containing from about 12 to 24 carbon
atoms; and beta-alkyloxy alkane sulfonates containing from
about 1 to 3 carbon atoms in the alkyl group and from about
8 to about 20 carbon atoms in the alkane moiety. Although
the acid salts are typically discussed and used, the acid
neutralization cam be performed as part of the fine
dispersion mixing step.
The preferred anionic surfactant pastes are mixtures
of linear or branched alkylbenzene sulfonates having an
alkyl of 10-16 carbon atoms and alkyl sulfates having an
alkyl of 10-18 carbon atoms. These pastes are usually
produced by reacting a liquid organic material with sulfur
trioxide to produce a sulfonic or sulfuric acid and then
neutralizing the acid to produce a salt of that acid. The
salt is the surfactant paste discussed throughout this
document. The sodium salt is preferred due to end
performance benefits and cost of NaOH vs. other
neutralizing agents, but is not required as other agents
such as KOH may be used.
Water-soluble nonionic surfactants are also useful as
secondary surfactant in the compositions of the invention.
Indeed, preferred processes use anionic/nonionic blends. A
particularly preferred paste comprises a blend of nonionic
and anionic surfactants having a ratio of from about 0.01:1
to about 1:1, more preferably about 0.05:1. Nonionics can
be used up to an equal amount of the primary organic
surfactant. Such nonionic materials include compounds
produced by the condensation of alkylene oxide groups
(hydrophilic in nature) with an organic hydrophobic
compound, which may be aliphatic or alkyl aromatic in
nature. The length of the polyoxyalkylene group which is
condensed with any particular hydrophobic group can be
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readily adjusted to yield a water-soluble compound having
the desired degree of balance between hydrophilic and
hydrophobic elements.
Suitable nonionic surfactants include the polyethylene
oxide condensates of alkyl phenols, e.g., the condensation
products of alkyl phenols having an alkyl group containing
from about 6 to 16 carbon atoms, in either a straight chain
or branched chain configuration, with from about 4 to 25
moles of ethylene oxide per mole of alkyl phenol.
Preferred nonionics are the water-soluble condensation
products of aliphatic alcohols containing from 8 to 22
carbon atoms, in either straight chain or branched
configuration, with from 4 to 25 moles of ethylene oxide
per more of alcohol. Particularly preferred are the
condensation products of alcohols having an alkyl group
containing from about 9 to 15 carbon atoms with from about
4 to 25 moles of ethylene oxide per mole of alcohol; and
condensation products of propylene glycol with ethylene
oxide.
Semi-polar nonionic surfactants include water-soluble
amine oxides containing one alkyl moiety of from about 10
to 18 carbon atoms and 2 moieties selected from the group
consisting of alkyl groups and hydroxyalkyl groups
containing from 1 to about 3 carbon atoms; water-soluble
phosphine oxides containing one alkyl moiety of about 10 to
18 carbon atoms and 2 moieties selected from the group
consisting of alkyl groups and hydroxyalkyl groups
containing from about 1 to 3 carbon atoms; and water-
soluble sulfoxides containing one alkyl moiety of from
about 10 to 18 carbon atoms and a moiety selected from the
group consisting of alkyl and hydroxyalkyl moieties of from
about 1 to 3 carbon atoms.
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Ampholytic surfactants include derivatives of
aliphatic or aliphatic derivatives of heterocyclic
secondary and tertiary amines in which the aliphatic moiety
can be either straight or branched chain and wherein one of
the aliphatic substituents contains from about 8 to 18
carbon atoms and at least one aliphatic substituent
contains an anionic water-solubilizing group.
Zwitterionic surfactants include derivatives of
aliphatic quaternary ammonium phosphonium, and sulfonium
compounds in which one of the aliphatic substituents
contains from about 8 to I8 carbon atoms.
Particularly preferred surfactants herein include
linear alkylbenzene sulfonates containing from about 11 to
14 carbon atoms in the alkyl group; tallow alkyl sulfates;
coconutalkyl glyceryl ether sulfonates; alkyl ether
sulfates wherein the alkyl moiety contains from about 14 to
18 carbon atoms and wherein the average degree of
ethoxylation is from about 1 to 4; olefin or paraffin
sulfonates containing from about 14 to 16 carbon atoms;
alkyldimethylamine oxides wherein the alkyl group contains
from about 11 to 16 carbon atoms; alkyldimethylammonio
propane sulfonates and alkyldimethylammonio hydroxy propane
sulfonates wherein the alkyl group contains from about 14
to 18 carbon atoms; soaps of higher fatty acids containing
from about 12 to 18 carbon atoms; condensation products of
C9-C15 alcohols with from about 3 to 8 moles of ethylene
oxide, and mixtures thereof.
Useful cationic surfactants include. Useful cationic
surfactants include water-soluble quaternary ammonium
compounds of the form R4R5R6R~N+X-, wherein R4 is alkyl
having from 10 to 20, preferably from 12-18 carbon atoms,
and R5, R6 and R~ are each C1 to C~ alkyl preferably
methyl; X- is an anion, e.g. chloride. Examples of such
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trimethyl ammonium compounds include C12-14 alkyl trimethyl
ammonium chloride and cocalkyl trimethyl ammonium
methosulfate.
Specific preferred surfactants for use herein include:
sodium linear C11-C13 alkylbenzene sulfonate; a-olefin
sulphonates; triethanolammonium C11-C13 alkylbenzene
sulfonate; alkyl sulfates, (tallow, coconut, palm,
synthetic origins, e.g. C45, etc.); sodium alkyl sulfates;
MES; sodium coconut alkyl glyceryl ether sulfonate; the
sodium salt of a sulfated condensation product of a tallow
alcohol with about 4 moles of ethylene oxide; the
condensation product of a coconut fatty alcohol with about
6 moles of ethylene oxide; the condensation product of
tallow fatty alcohol with about 11 moles of ethylene oxide;
the condensation of a fatty alcohol containing fram about
14 to about 15 carbon atoms with about 7 moles of ethylene
oxide; the condensation product of a C12-C13 fatty alcohol
with about 3 moles of ethylene oxide; 3-(N,N-dimethyl-N-
coconutalkylammonio)-2-hydroxypropane-1-sulfonate; 3-(N,N-
dimethyl-N-coconutalkylammonio)-propane-1-sulfonate; 6- (N-
dodecylbenzyl-N,N-dimethylammonio) hexanoate;
dodecyldimethylamine oxide; coconutalkyldimethylamine
oxide; and the water-soluble sodium and potassium salts of
coconut and tallow fatty acids.
(As used herein, the term "surfactant" means non-
nonionic surfactants, unless otherwise specified. The
ratio of the surfactant active (excluding the nonionic(s))
to dry detergent builder or powder ranges from 0.005 to
19:1, preferably from 0.05 to 10:1, and more preferably
from 0.1:1 to 5:1. Even more preferred said surfactant
active to builder ratios are 0.15:1 to 1:1; and 0.2:1 to
0.5:1) .
The Extruder
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The extruder fulfils the functions of pumping and mixing
the viscous surfactant paste on a continuous basis. A basic
extruder consists of a barrel with a smooth inner
cylindrical surface. Mounted within this barrel is the
extruder screw. There is an inlet port for the high active
paste which, when the screw is rotated, causes the paste to
be moved along the length of the barrel.
The detailed design of the extruder allows various
functions to be carried out. Firstly additional ports in
the barrel may allow other ingredients, including the alkyl
sulphate powder to be added directly into the barrel.
Secondly means for heating or cooling may be installed in
the wall of the barrel for temperature control. Thirdly,
careful design of the extruder screw promotes mixing of the
paste both with itself and with other additives.
A preferred extruder is the twin screw extruder. This type
of extruder has two screws mounted in parallel within the
same barrel, which are made to rotate either in the same
direction (co-rotation) or in opposite directions (counter-
rotation). The co-rotating twin screw extruder is the most
preferred piece of equipment for use in this invention.
Suitable twin screw extruders for use in the present
invention include those supplied by . APV Bakes, (CP
series); Werner and Pfleiderer, (Continua Series); Wenger,
(TF Series); Leistritz, (ZSE Series); and Buss, (LR
Series ) .
The Fine Dispersion Mixing and Granulation
The term "fine dispersion mixing and/or granulation,"
as used herein, means mixing and/or granulation of the
above mixture in a fine dispersion mixer at a blade tip
speed of from about 5m/sec. to about 50 m/sec., unless
otherwise specified. The total residence time of the
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mixing and granulation process is preferably in the order
of from 0.1 to 10 minutes, more preferably 0.1-5 and most
preferably 0.2-4 minutes. The more preferred mixing and
granulation tip speeds are about 10-45 m/sec. and about 15-
40 m/sec.
Any apparatus, plants or units suitable for the
processing of surfactants can be used for carrying out the
process according to the invention. Suitable apparatus
includes, for example, falling film sulphonating reactors,
digestion tanks, esterification reactors, etc. For mixing/
agglomeration any of a number of mixers/agglomerators can
be used. In one preferred embodiment, the process of the
invention is continuously carried out. Especially
preferred are mixers of the FukaeR FS-G series manufactured
by Fukae Powtech Kogyo Co., Japan; this apparatus is
essentially in the form of a bowl-shaped vessel accessible
via a top port, provided near its base with a stirrer
having a substantially vertical axis, and a cutter
positioned on a side wall. The stirrer and cutter may be
operated independently of one another and at separately
variable speeds. The vessel can be fitted with a cooling
jacket or, if necessary, a cryogenic unit.
Other similar mixers found to be suitable for use in
the process of the invention include DiosnaR V series ex
Dierks & Sohne, Germany; and the Pharma MatrixR ex T K
Fielder Ltd., England. Other mixers believed to~be
suitable for use in the process of the invention are the
FujiR VG-C series ex Fuji Sangyo Co., Japan; and the RotoR
ex Zanchetta ~ Co srl, Italy.
Other preferred suitable equipment can include
EirichR, series RV, manufactured by Gustau Eirich Hardheim,
Germany; LodigeR, series FM for batch mixing, series Baud
KM for continuous mixing/agglomeration, manufactured by
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Lodige Machinenbau GmbH, Paderborn Germany; DraisR T160
series, manufactured by Drais Werke GmbH, Mannheim Germany;
and WinkworthR RT 25 series, manufactured by Winkworth
Machinery Ltd., Bershire, England.
The Littleford Mixer, Model #FM-130-D-12, with
internal chopping blades and the Cuisinart Food Processor,
Model #DCX-Plus, with 7.75 inch (29.7 cm) blades are two
examples of suitable mixers. Any other mixer with fine
dispersion mixing and granulation capability and having a
residence time in the order of 0.1 to 10 minutes can be
used. The "turbine-type" impeller mixer, having several
blades on an axis of rotation, is preferred. The invention
can be practiced as a batch or a continuous process.
Operating' Temperatures
Preferred operating temperatures should also be as low
as possible since this leads to a higher surfactant
concentration in the finished particle. Preferably the
temperature during the agglomeration is less than 100°C,
more preferably between 25 and 90°C, and most preferably
between 30 and 80°C.
Final AQCxlomerate Composition
The present invention produces granules of high
density for use in detergent compositions. A preferred
composition of the final agglomerate for incorporation into
granular detergents has a high surfactant concentration.
By increasing the concentration of surfactant, the
particles/agglomerates made by the present invention are
more suitable for a variety of different formulations.
These high surfactants containing particle agglomerates
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require fewer finishing techniques to reach the final
agglomerates, thus freeing up large amounts of processing
aids (inorganic powders, etc.) that can be used in other
processing steps of the overall detergent manufacturing
process (spray drying, dusting off, etc).
The granules made according to the present invention
are large, low dust and free flowing, and preferably have a
bulk density of from about 0.4 to about 1.2 g/cc, more
preferably from about 0.6 to about 0.8 g/cc. The weight
average particle size of the particles of this invention
are from about 200 to about 1000 microns. The preferred
granules so formed have a particle size range of from 200
to 2000 microns. The more preferred granulation
temperatures range from about 25°C to about 60°C, and most
preferably from about 30°C to about 50°C.
Dryinct
The desired moisture content of the free flowing granules
of this invention can be adjusted to levels adequate for
the intended application by drying in conventional powder
drying equipment such as fluid bed dryers. If a hot air
fluid bed dryer is used, care must be exercised to avoid
degradation of heat sensitive components of the granules.
It is also advantageous to have a cooling step prior to
large scale storage. This step can also be done in a
conventional fluid bed operated with cool air. The
drying/cooling of the agglomerates can also be done in any
other equipment suitable for powder drying such as rotary
dryers, etc.
For detergent applications, the final moisture of the
agglomerates needs to be maintained below levels at which
the agglomerates can be stored and transported in bulk.
The exact moisture level depends on the composition of the
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agglomerate but is typically achieved at levels of 1-8%
free water (i.e. water not associated to any crystalline
species in the agglomerate) and most typically at 2-4%.
Deterctency Builders and Powders
Any compatible detergency builder or combination of
builders or powder can be used in the process and
compositions of the present invention.
The detergent compositions herein can contain
crystalline aluminosilicate ion exchange material of the
f ormu 1 a
Naz C (A102 ) z ~ C Si02 ) y7 ~ xH20
wherein z and y are at least about 6, the molar ratio of z
to y is from about 1.0 to about 0.4 and z is from about 10
to about 264. Amorphous hydrated aluminosilicate materials
useful herein have the empirical formula
Mz(zA102~ySi02)
wherein M is sodium, potassium, ammonium or substituted
ammonium, z is from about 0.5 to about 2 and y is 1, said
material having a magnesium ion exchange capacity of at
least about 50 milligram equivalents of CaC03 hardness per
gram of anhydrous aluminosilicate. Hydrated sodium Zeolite
A with a particle size of from about 1 to 10 microns is
preferred.
The aluminosilicate ion exchange builder materials
herein are in hydrated form and contain from about 10% to
about 28% of water by weight if crystalline, and
potentially even higher amounts of water if amorphous.
Highly preferred crystalline aluminosilicate ion exchange
materials contain from about 18% to about 22% water in
their crystal matrix. The crystalline aluminosilicate ion
exchange materials are further characterized by a particle
size diameter of from about 0.1 micron to about 10 microns.
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Amorphous materials are often smaller, e.g., down to less
than about 0.01 micron. Preferred ion exchange materials
have a particle size diameter of from about 0.2 micron to
about 4 microns. The term "particle size diameter" herein
represents the average particle size diameter by weight of
a given ion exchange material as determined by conventional
analytical techniques such as, for example, microscopic
determination utilizing a scanning electron microscope.
The crystalline aluminosilicate ion exchange materials
herein are usually further characterized by their calcium
ion exchange capacity, which is at least about 200 mg
equivalent of CaC03 water hardness/g of aluminosilicate,
calculated on an anhydrous basis, and which generally is in
the range of from about 300 mg eq./g to about 352 mg eq./g.
The aluminosilicate ion exchange materials herein are still
further characterized by their calcium ion exchange rate
which is at least about 2 grains
Ca++/gallon/minute/gram/gallon of aluminosilicate
(anhydrous basis), and generally lies within the range of
from about 2 grains/gallon/minute/gram/gallon to about 6
grains/gallon/minute/gram/gallon, based on calcium ion
hardness. Optimum aluminosilicate for builder purposes
exhibit a calcium ion exchange rate of at least about 4
grains/gallon/minute/gram/gallon.
The amorphous aluminosilicate ion exchange materials
usually have a Mg++ exchange of at least about 50 mg eq.
CaC03/g (12 mg Mg++/g) and a Mg++ exchange rate of at least
about 1 grain/gallon/minute/gram/gallon. Amorphous
materials do not exhibit an observable diffraction pattern
when examined by Cu radiation (1.54 Angstrom Units).
Aluminosilicate ion exchange materials useful in the
practice of this invention are commercially available. The
aluminosilicates useful in this invention can be
crystalline or amorphous in structure and can be naturally
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occurring aluminosilicates or synthetically derived. A
method for producing aluminosilicate ion exchange materials
is discussed in U.S. Pat. No. 3,985,669, Krummel et al.,
issued Oct. 12, 1976.
Preferred synthetic crystalline aluminosilicate ion
exchange materials useful herein are available under the
designations Zeolite A, Zeolite B, Zeolite X and Zeolite P.
In an especially preferred embodiment, the crystalline
aluminosilicate ion exchange material has the formula
Nal2 [ (A102) 12 (Si02) 12] Wi20
wherein x is from about 20 to about 30, especially about 27
and has a particle size generally less than about 5
microns.
The granular detergents of the present invention can
contain neutral or alkaline salts which have a pH in
solution of seven or greater, and can be either organic or
inorganic in nature. The builder salt assists in providing
the desired density and bulk to the detergent granules
herein. While some of the salts are inert, many of them
also function as detergency builder materials in the
laundering solution.
Examples of neutral water-soluble salts include the
alkali metal, ammonium or substituted ammonium chlorides,
fluorides and sulfates. The alkali metal, and especially
sodium, salts of the above are preferred. Sodium sulfate
is typically used in detergent granules and is a
particularly preferred salt. Citric acid and, in general,
any other organic or inorganic acid may be incorporated
into the granular detergents of the present invention as
long as it is chemically compatible with the rest of the
agglomerate composition.
Other useful water-soluble salts include the compounds
commonly known as detergent builder materials. Builders
CA 02260008 2001-04-25
are generally selected from the various water-soluble,
alkali metal, ammonium or substituted ammonium phosphates,
polyphosphates, phosphonates, polyphosphonates, carbonates,
silicates, borates, and polyhyroxysulfonates, Preferred
are the alkali metal, especially sodium, salts of the
above.
Specific examples of inorganic phosphate builders are
sodium and potassium tripolyphosphate, pyrophosphate,
polymeric metaphosphate having a degree of polymerization
of from about 6 to 21, and orthophosphate. Examples of
polyphosphonate builders are the sodium and potassium salts
of ethylene diphosphonic acid, the sodium and potassium
salts of ethane 1-hydroxy-1,1-diphosphonic acid and the
sodium and potassium salts of ethane, 1,1,2-triphosphonic
acid. Other phosphorus builder compounds are disclosed in
U.S. Pat. Nos. 3,159,581; 3,213,030; 3,422,021; 3,422,137;
3,400,176 and 3,400,148.
Examples of nonphosphorus, inorganic builders are
sodium and potassium carbonate, bicarbonate,
sesquicarbonate, tetraborate decahydrate, and silicate
having a molar ratio of Si02 to alkali metal oxide of from
about 0.5 to about 4.0, preferably from about 1.0 to about
2.4. The compositions made by the process of the present
invention does not require excess carbonate for processing,
and preferably does not contain over 2s finely divided
calcium carbonate as disclosed in U.S. Pat. No. 4,196,093,
Clarke et al., issued Apr.l, 1980, and is preferably free
of the latter.
As mentioned above powders normally used in detergents
such as zeolite, carbonate, silica, silicate, citrate,
phosphate, perborate, etc. and process aids such as starch,
soap or fatty acid can be used in preferred embodiments of
the present invention.
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Polymers
Also useful are various organic polymers, some of
which also may function as builders to improve detergency.
Included among such polymers may be mentioned sodium
carboxy-lower alkyl celluloses, sodium lower alkyl
celluloses and sodium hydroxy-lower alkyl celluloses, such
as sodium carboxymethyl cellulose, sodium methyl cellulose
and sodium hydroxypropyl cellulose, polyvinyl alcohols
(which often also include some polyvinyl acetate),
polyacrylamides, polyacrylates and various copolymers, such
as those of malefic and acrylic acids. Molecular weights
for such polymers vary widely but most are within the range
of 2,000 to 100,000.
Polymeric polycarboxyate builders are set forth in
U.S. Patent 3,308,067, Diehl, issued March 7, 1967. Such
materials include the water-soluble salts of homo-and
copolymers of aliphatic carboxylic acids such as malefic
acid, itaconic acid, mesaconic acid, fumaric acid, aconitic
acid, citraconic acid and methylenemalonic acid.
Optionals
Other ingredients commonly used in detergent
compositions can be included in the compositions of the
present invention. These include flow aids, color
speckles, bleaching agents and bleach activators, suds
boosters or suds suppressors, antitarnish and anticorrosion
agents, soil suspending agents, soil release agents, dyes,
fillers, optical brighteners, germicides, pH adjusting
agents, nonbuilder alkalinity sources, hydrotropes,
enzymes, enzyme-stabilizing agents, chelating agents,
perfumes, soap and fatty acid.
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EXAMPLES
In the following examples all percantages are by weight
unless otherwise stated:
AS/AE3S paste is a 78o aqueous solution of alkyl sulphate
and alkyl ether sulphate (with 3 EO groups per molecule)
comprising 4 parts of alkyl sulphate to 1 part of alkyl
ether sulphate.
LAS paste is a 78% active aqueous solution of sodium linear
alkyl benzene sulphonate
AS powder comprises 95% active powder
Polyacrylate powder comprises co-polymer of acrylic and
maliec acid
Silicate powder comprises 80o sodium silicate and is
produced by spray-drying
Ex. 1 Ex. 2 Comparative
Ex. 3
AS/AE3S Paste 16 32 38
LAS paste 20 - -
Alkyl sulphate powder 4 18 -
Polyacrylate polymer - 7 17
Sodium carbonate 20 20 12
Zeolite A 29 15 22
Silicate powder 1 -
Water / Misc. minors 10 8 11
In each of examples 1 to 3 the AE3S/AS paste, and the LAS
paste when present, were fed into a continuous twin-screw
extruder. The alkyl sulphate powder, or the polyacrylate
polymer, and silicate when present, were added directly to
into the barrel of the extruder through an inlet port. The
mixture was then extruded through a die directly into a
high shear mixer (Loedige~ CB) where is mixed with powder
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streams comprising the sodium carbonate and the zeolite.
The resulting product was then passed to a medium shear
mixer (Loedige° KM) resulting in a free-flowing detergent
product in the form of agglomerates.
The bulk density of the product from each of the examples
was between 680 and 700 g/1.
AS/NI paste is a 95% aqueous solution of alkyl sulphate and
alcohol ethoxylate (with 3 EO groups per molecule)
comprising 2 parts of alkyl sulphate to 1 part of alcohol
ethoxylate.
LAS/NI paste is a 95°s active aqueous solution of sodium
linear alkyl benzene sulphonate and alcohol ethoxylate
(with 3 EO groups per molecule) comprising 2 parts of LAS
to 1 part of alcohol ethoxylate.
Ex. 4 Ex. 5 Comparative
Ex. 6
AS/NI Paste 30 - 30
LAS/NI paste - 30 -
Alkyl sulphate powder 20 20 -
Zeolite MAP 35 35 55
Sodium citrate 5 5 5
Water / Misc. minors 10 10 10
In each of examples 4 and 5 the AS/NI paste, or the LAS/NI
paste, was fed into a continuous twin-screw extruder. The
alkyl sulphate powder was added directly to into the barrel
of the extruder through an inlet port. The mixture was then
extruded through a die directly into a high shear mixer
(Loedige° CB) where is mixed with powder streams comprising
the sodium citrate and the zeolite. The resulting product
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was then passed to a medium shear mixer (Loedige~ KM)
resulting in a free-flowing detergent product in the form
of agglomerates.
In comparative example 6 the AS/NI paste was fed diectly
into the high shear mixer.
The bulk density of the product from each of the examples
was between 680 and 700 g/1.
