[0001] The present invention relates to a process for preparing a particulate detergent
composition, in particular by spray drying an aqueous slurry. Particulate detergent
compositions are also disclosed.
[0002] Many granular detergents which are sold commercially comprise sodium aluminosilicate
as the sole builder, or as a component of a builder system. It is known, for example
from JP204098/1983, laid open on November 28th 1983, that heated aqueous slurries,
such as those used in conventional spray-drying processes, which comprise both sodium
aluminosilicate and water-soluble silicate, cause insoluble complexes to form. These
insoluble complexes are undesirable in laundry detergents because they can result
in residues on washed fabrics. Furthermore, without the silicate to act as a powder
structurant, the particle size distribution of the spray-dried powder may be unacceptably
broad.
[0003] In the absence of water-soluble silicate in the aqueous slurry, various other components
have been proposed as powder structurants, useful to achieve a crisp, free-flowing
spray-dried powder. Included amongst the powder structurants that have been suggested
are film-forming polymer: polycarboxylates (for example, US-A-4 379 080); polyacrylates
(for example, JP204098/1983); sucrose and derivatives (for example, EP-A-0 215 637)
; sodium sesquicarbonate (for example, EP-A-0 242 138).
[0004] However, unless the powder structurants are required by the formulator as active
ingredients, then they are an expensive processing aid.
[0005] An aqueous slurry which does not comprise either water-soluble silicate, or one of
the alternative powder structurants is difficult to spray dry. In particular high
water concentrations are generally needed in order to maintain the viscosity of the
slurry low enough to provide crisp, free-flowing particles of the desired particle
size when spray-dried. The disadvantage of high water concentrations is that the excess
water must be removed during the drying step and a lot of energy is needed to do this.
[0006] WO90/04630, published on 3rd May 1990, describes a process for preparing a carbonate
containing detergent slurry comprising an alkylpolyglycoside and an alkali metal chloride.
Zeolite A is suggested as one possible builder albeit in the presence of silicate
(at 7% by weight in Table VI).
[0007] EP-A-0,326,208 describes porous pouched granular detergents having improved dispensing
properties and reduced dusting due to the incorporation of a hygroscopic builder salt
selected from a specified group of a large number of organic salts. EP-A-0,257,514
describes detergents comprising surfactant and zeolite, alkali silicate, anionic functional
organosiliconate and complexing agent for trivalent aluminium. The combination of
the organosiliconate and the complexing agent is said to give improved dissolution
characteristics.
[0008] The object of the present invention is to avoid residue problems by substantially
omitting silicate from an aqueous slurry which comprises anionic surfactant and aluminosilicate,
and at the same time to provide a low viscosity slurry suitable for spray-drying to
form crisp, free-flowing powder.
Summary of the Invention
[0009] According to the invention a process is provided for preparing a particulate detergent
composition comprising less than 2% by weight silicate, the process comprising forming
an aqueous slurry comprising at least 0.5% by weight sodium aluminosilicate and which
further comprises less than 5% by weight of silicate and an inorganic salt, or a mixture
of inorganic salts, and whereby the inorganic salt is added in an amount of at least
1% by weight and sufficient to increases the ionic conductivity of the aqueous slurry,
and subsequently drying the aqueous slurry to form the particulate detergent composition.
[0010] Preferably the inorganic salt is an alkali metal or alkaline earth metal salt, or
mixtures thereof of halide or, nitrate most preferably sodium chloride.
[0011] In a more preferred embodiment of the invention the step of adding the inorganic
salt raises the ionic conductivity of the aqueous slurry by at least 3 milliSiemens,
and preferably by at least 5 milliSiemens.
[0012] A further aspect of the invention concerns spray-dried detergent powder compositions.
Preferred compositions comprise:
at least one surfactant, and preferably at least 5% by weight of surfactant;
from 2 to 80%, and preferably from 10% to 50% by weight of aluminosilicate
from 1% to 20% by weight of an inorganic salt selected from the group consisting of
alkali metal halides, nitrates, or mixtures thereof, and preferably from 2% to 10%
by weight of an alkali metal, preferably sodium, chloride and less than 2% by weight
of silicate.
Detailed Description of the Invention
[0013] Essential components of the compositions of the present invention are aluminosilicate
builders such as those having the empirical formula:
M
z (zAlO
2)
y ] · x H
2O
wherein z and y are integers of at least 6, the molar ratio of z to y is in the range
from 1.0 to about 0.5, and x is an integer from about 15 to about 264.
[0014] Useful aluminosilicate ion exchange materials are commercially available. These aluminosilicates
can be crystalline or amorphous in structure and can be naturally-occurring aluminosilicates
or synthetically derived. A method for producing aluminosilicate ion exchange materials
is disclosed in US Patent 3,985,669, Krummel et al, issued October 12, 1976. Preferred
synthetic crystalline aluminosilicate ion exchange materials useful herein are available
under the designations zeolite A, zeolite P(B), zeolite MAP, zeolite X and zeolite
Y. In an especially preferred embodiment, the crystalline aluminosilicate ion exchange
material has the formula :
Na
12 [(AlO
2)
12 (SiO2)
12 ] · x H
2O
wherein x is from about 20 to about 30, especially about 27. This material is known
as zeolite A. Dehydrated zeolites (x=0-10), and "overdried" zeolites (x=10-20) may
also be used herein. The "overdried" zeolites are particularly useful when a low moisture
environment is required, for example to improve stability of detergent bleaches such
as perborate and percarbonate. Preferably, the aluminosilicate has a particle size
of about 0.1-10 micrometers in diameter. Preferred ion exchange materials have a particle
size diameter of from about 0.2 micrometers to about 4 micrometers. 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 zeolite A materials herein are usually further characterized by their
calcium ion exchange capacity, which is at least about 200 mg equivalent of CaCO
3 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 zeolite
A materials herein are still further characterized by their calcium ion exchange rate
which is at least about 2 grains Ca
++/gallon/minute/gram/gallon (0.13g Ca
++/litre/minute/gram/litre) of aluminosilicate (anhydrous basis), and generally lies
within the range of from about 2 grains/gallon/minute/gram/gallon(0.13g Ca
++/litre/minute/gram/litre) to about 6 grains/gallon/minute/gram/gallon (0.39g Ca
++/litre/minute/gram/litre), 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
(0.26g Ca
++/litre/minute/gram/litre).
[0015] The granular agglomerates of the present invention also comprise other detergent
ingredients.
[0016] 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.
[0017] 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 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 (C
8-C
18 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; and methyl
ester sulphonates. 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 C
11-C
13 LAS.
[0018] 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.
[0019] 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 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.
[0020] Water-soluble nonionic surfactants are also useful as surfactants in the compositions
of the invention. Indeed, preferred processes use anionic/nonionic blends. 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 readily adjusted to yield a water-soluble
compound having the desired degree of balance between hydrophilic and hydrophobic
elements.
[0021] 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.
[0022] 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 1 to 25 moles of ethylene oxide per mole of alcohol, especially 2 to 7 moles
of ethylene oxide per mole of alcohol. Particularly preferred are the condensation
products of alcohols having an alkyl group containing from about 9 to 15 carbon atoms;
and condensation products of propylene glycol with ethylene oxide.
[0023] Other preferred nonionics are polyhydroxy fatty acid amides which may be prepared
by reacting a fatty acid ester and an N-alkyl polyhydroxy amine. The preferred amine
for use in the present invention is N-(Rl)-CH2(CH2OH)4-CH2-OH and the preferred ester
is a C12-C20 fatty acid methyl ester. Most preferred is the reaction product of N-methyl
glucamine (which may be derived from glucose) with C12-C20 fatty acid methyl ester.
[0024] Methods of manufacturing polyhydroxy fatty acid amides have been described in WO
9206073, published on 16th April, 1992. This application describes the preparation
of polyhydroxy fatty acid amides in the presence of solvents. In a highly preferred
embodiment of the invention N-methyl glucamine is reacted with a C12-C20 methyl ester.
It also says that the formulator of granular detergent compositions may find it convenient
to run the amidation reaction in the presence of solvents which comprise alkoxylated,
especially ethoxylated (EO 3-8) C12-C14 alcohols (page 15, lines 22-27). This directly
yields nonionic surfactant systems which are suitable for use in the present invention,
such as those comprising N-methyl glucamide and C12-C14 alcohols with an average of
3 ethoxylate groups per molecule.
[0025] 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.
[0026] 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.
[0027] Zwitterionic surfactants include derivatives of aliphatic quaternary ammonium phosphonium,
and sulfonium compounds in which one of the aliphatic substituents contains from about
8 to 18 carbon atoms.
[0028] Useful cationic surfactants include water-soluble quaternary ammonium compounds of
the form R
4R
5R
6R
7N
+X
-, wherein R
4 is alkyl having from 10 to 20, preferably from 12-18 carbon atoms, and R
5, R
6 and R
7 are each C
1 to C
7 alkyl preferably methyl; X
- is an anion, e.g. chloride. Examples of such trimethyl ammonium compounds include
C
12-14 alkyl trimethyl ammonium chloride and cocalkyl trimethyl ammonium methosulfate.
[0029] 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.
[0030] Useful water-soluble salts include the compounds commonly known as detergent builder
materials. Builders are generally selected from the various water-soluble, alkali
metal, ammonium or substituted ammonium phosphates, polyphosphates, phosphonates,
polyphosphonates, carbonates, silicates, borates, and polyhydroxysulfonates. Preferred
are the alkali metal, especially sodium, salts of the above.
[0031] 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.
[0032] Examples of nonphosphorus, inorganic builders are sodium and potassium carbonate,
bicarbonate, sesquicarbonate, tetraborate decahydrate, and silicate having a molar
ratio of SiO
2 to alkali metal oxide of from about 0.5 to about 4.0, preferably from about 1.0 to
about 2.4.
Polymers
[0033] 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, homo & co polymers of amino acids (particularly homo and co polymers of
aspartic acid glutamic acid), polyvinyl alcohols (which often also include some polyvinyl
acetate), polyacrylamides, polyacrylates and various copolymers, such as those of
maleic and acrylic acids, in particular maleic/acrylic/vinyl alcohol terpolymers.
Molecular weights for such polymers vary widely but most are within the range of 2,000
to 100,000. Other suitable polymers are polyamine N-oxide polymers, copolymers of
N-vinylpyrrolidone and N-vinylimidazole, polyvinylpyrrolidone polymers, polyvinyloxazolidones
and polyvinylimidazoles or mixtures thereof.
[0034] 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 maleic acid, itaconic acid, mesaconic acid,
fumaric acid, aconitic acid, citraconic acid, methylenemalonic acid, methyl acrylic
and PEG. In the present invention it is preferred that polymeric polycarboxylates
are substantially omitted from the aqueous slurry. By substantially omitted, less
than 5% by weight of the aqueous slurry is preferred, and less than 2% by weight is
more preferred.
Inorganic salts
[0035] Whilst the skilled person has a wide range of inorganic salts from which to choose,
it is an essential feature of the present invention that the inorganic salt should
result in an increased ionic conductivity of the aqueous slurry. The ionic conductivity
of the aqueous slurry depends not only on the inorganic salt used, but also on the
amount of inorganic salt used, and also on the composition of the aqueous slurry.
Halides, especially chlorides and nitrates have been found to be particularly effective
inorganic salts which when used at the preferred levels, have the effect of increasing
the ionic conductivity of the aqueous slurry. Carbonates and sulphates are less effective,
and may well cause a decrease in the ionic conductivity of the slurry. Without wishing
to be bound by theory, it is believed that the higher ionic conductivity of the aqueous
slurry suppresses the formation of highly viscous surfactant phases which are subsequently
difficult to dry. By promoting less viscous surfactant phases the aqueous slurry is
more readily formed into free-flowing, crisp particles having a good particle size
distribution.
Silicone Oils
[0036] Particulate suds suppressors may also be incorporated into the finished composition
by dry adding. Preferably the suds suppressing activity of these particles is based
on fatty acids or silicones.
Optionals
[0037] 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, anionic and nonionic soil release agents, dyes, clays,
flocculating agents, STS, fillers, optical brighteners, germicides, pH adjusting agents,
nonbuilder alkalinity sources, hydrotropes, enzymes, enzyme-stabilizing agents, chelating
agents, (including EDDS) and perfumes.
[0038] These optional ingredients, especially optical brighteners, may be incorporated either
directly in the agglomerates herein or may be components of separate particles suitable
for dry adding to the agglomerates of the present invention.
Processing
[0039] The aqueous slurry may be prepared by a batch or continuous process. Most conveniently
a batch mixer, or "crutcher" is used in which the various detergent components or
dissolved in, or slurried with, water. Typically the aqueous slurry contains from
about 20% to about 60% by weight of water, in particular from about 30% to about 40%
by weight of water. This is referred to as the crutcher mix moisture. In the process
of the present invention, the order of addition of the inorganic salt and the other
components of the aqueous slurry (or "crutcher mix") is not considered to be critical.
It is an essential feature of the present invention that the ionic conductivity of
the aqueous slurry which comprises the inorganic salt must be greater than the ionic
conductivity of the aqueous slurry in the absence of the inorganic salt. It is preferred
that the addition of the inorganic salt results in an aqueous slurry having an ionic
conductivity which is at least 3 milliSiemens higher than a corresponding aqueous
slurry from which the inorganic salt has been omitted.
[0040] The drying of the aqueous slurry may be achieved by any one of several processes
known to the skilled man, but it is preferably prepared by spray drying. Following
the spray drying route, an aqueous slurry is prepared comprising the solids. The slurry
is then pumped at high pressure through atomising nozzles into a drying tower where
excess water is driven off, producing a flowable powder. The resulting powder may
then be oversprayed with liquid ingredients, especially nonionic surfactants for which
the powder has a high adsorption capacity before it loses its good flow characteristics.
Other powdered components of the finished laundry detergent may be dry mixed with
the flowable powder produced by the above process.
TEST METHOD
Procedure for the Conductivity Test
[0041]
1. Prepare a 15kg sample of aqueous slurry ready for spray drying.
2. Place the sample in a large bucket 400mm diameter and 500mm in height.
3. Let the mix cool to 30°C.
4. Using a Jenwat 4020 Conductivity Meter, measure the conductivity of the aqueous
slurry.
EXAMPLES
[0042]
[0043] The aqueous slurry is heated to 70°C and is fed through to a series of pressure pumps.
This increases the pressure of the mix up to 80 bar. Air is then injected into the
mix at a pressure of 100 bar. The high pressure mix is then directed to the top of
the spray drying tower. Here it is blown through a set of nozzles, which range in
aperture diameter up to 1mm. These atomise the slurry into droplets. The moisture
is driven off these particles as they fall through the tower with a residence time
of up to 180 seconds by contact with hot air at 275°C. At the bottom of the tower
a blown powder is collected with a density in the range of 300 - 550g/l. The resulting
blown powder has a moisture in the range of 5 -_15% with the majority of the particles
having a size in the range of 150 - 1200 micrometers.
1. A process for preparing a particulate detergent composition comprising less than 2%
by weight of silicate, the process comprising:
(a) forming an aqueous slurry comprising water, anionic surfactant and at least 0.5%
of sodium aluminosilicate,
(b) adding an inorganic salt, or mixture of inorganic salts, to the aqueous slurry,
(c) drying the slurry
characterised in that the inorganic salt is added in an amount of at least 1% by weight of the aqueous
slurry, and is sufficient to increase the ionic conductivity of the aqueous slurry,
and wherein the aqueous slurry comprises less than 5% by weight of silicate.
2. A process according to claim 1 wherein the inorganic salt is selected from the group
consisting of alkali metal salts of halides, nitrates or mixtures thereof.
3. A process according to claim 1 wherein the inorganic salt is selected from the group
consisting of alkaline earth metal salts of halides, nitrates or mixtures thereof.
4. A process according to claim 2 wherein the inorganic salt is sodium chloride.
5. A process according to any of the previous claims wherein the step of adding the inorganic
salt raises the ionic conductiveity of the aqueous slurry by at least 3 milliSiemens.
6. A process according to claim 1 wherein the range of anionic surfactant is 1% to 50%,
more preferably from 5% to 20% by weight.
7. A process according to claim 1 wherein the range of sodium aluminosilicate is 1% to
50%, more preferably from 5% to 30% by weight.
8. A process according to claim 1 wherein the range of inorganic salt is 1% to 50%, more
preferably from 1% to 10% by weight.
9. A process according to any preceding claim in which the slurry is dried in a spray-drying
step.
10. A spray-dried powder comprising:
(a) at least one surfactant,
(b) from 2% to 80% by weight of aluminosilicate
(c) from 1% to 20% by weight of an inorganic salt selected from the group consisting
of alkali metal, alkaline earth metal salts, or mixtures thereof of halide, nitrates,
or mixtures thereof, and
(d) less than 2% by weight of silicate.
11. A spray-dried powder according to claim 10 comprising :
(a) at least 5% by weight of surfactant ;
(b) from 10% to 50% by weight of aluminosilicate,
(c) from 2% to 10% by weight of an alkali metal, preferably sodium, chloride, and
(d) less than 2% by weight of silicate.
1. Verfahren zur Herstellung einer teilchenförmigen Detergenszusammensetzung, umfassend
weniger als 2 Gew.-% Silicat, wobei das Verfahren umfasst:
(a) Bilden einer wässrigen Aufschlämmung, umfassend Wasser, anionisches Tensid und
mindestens 0,5% Natriumaluminosillcat.
(b) Zugeben eines anorganischen Salzes oder einer Mischung anorganischer Salze zu
der wässrigen Aufschlämmung,
(c) Trocknen der Aufschlämmung
dadurch gekennzeichnet, dass das anorganische Salz in einer Menge von mindestens 1 Gew.-% der wässrigen Aufschlämmung
zugegeben wird und ausreichend ist, um die ionische Leitfähigkeit der wässrigen Aufschlämmung
zu erhöhen, und wobei die wässrige Aufschlämmung weniger als 5 Gew.-% Silicat umfasst.
2. Verfahren nach Anspruch 1, wobei das anorganische Salz aus der Gruppe gewählt ist,
bestehend aus Alkalimetallsalzen von Halogeniden, Nitraten oder Mischungen hiervon.
3. Verfahren nach Anspruch 1, wobei das anorganische Salz aus der Gruppe gewählt ist,
bestehend aus Erdalkalimetallsalzen von Halogeniden, Nitraten oder Mischungen hiervon.
4. Verfahren nach Anspruch 2, wobei das anorganische Salz Natriumchlorid ist.
5. Verfahren nach mindestens einem der vorangehenden Ansprüche, wobei der Schritt des
Zugebens des anorganischen Salzes die ionische Leitfähigkeit der wässrigen Aufschlämmung
um mindestens 3 milliSiemens erhöht.
6. Verfahren nach Anspruch 1, wobei der Bereich des anionischen Tensids 1% bis 50%, weiter
vorzugsweise 5 bis 20 Gew.-% beträgt.
7. Verfahren nach Anspruch 1, wobei der Bereich an Natriumaluminosilicat 1% bis 50%,
weiter vorzugsweise 5 bis 30 Gew.-% beträgt.
8. Verfahren nach Anspruch 1, wobei der Bereich des anorganischen Salzes 1% bis 50%,
weiter vorzugsweise 1 bis 10 Gew.-% beträgt.
9. Verfahren nach mindestens einem der vorangehenden Ansprüche, wobei die Aufschlämmung
in einem Sprühtrocknungsschritt getrocknet wird.
10. Sprühgetrocknetes Pulver, umfassend:
(a) mindestens ein Tensid,
(b) 2 bis 80 Gew.-% Aluminosilicat,
(c) 1 bis 20 Gew.-% anorganisches Salz, gewählt aus der Gruppe, bestehend aus Alkalimetall-,
Erdalkalimetallsalzen oder Mischungen hiervon aus Halogenid, Nitraten oder Mischungen
hiervon, und
(d) weniger als 2 Gew.-% Silicat.
11. Sprühgetrocknetes Pulver nach Anspruch 10, umfassend:
(a) mindestens 5 Gew.-% Tensid,
(b) 10 bis 50 Gew.-% Aluminosilicat,
(c) 2 bis 10 Gew.-% eines Alkalimetall- vorzugsweise Natrium-, -Chlorids, und
(d) weniger als 2 Gew.-% Silicat.
1. Procédé de préparation d'une composition détergente particulaire comprenant moins
de 2% en poids de silicate, le procédé comprenant les étapes consistant à :
(a) former une suspension aqueuse comprenant de l'eau, un tensioactif anionique et
au moins 0,5% d'aluminosilicate de sodium,
(b) ajouter un sel minéral, ou un mélange des sels minéraux, à la suspension aqueuse,
(c) sécher la suspension
caractérisé en ce qu'on ajoute le sel minéral en une quantité d'au moins 1% en poids de la suspension aqueuse,
et suffisante pour augmenter la conductivité ionique de la suspension aqueuse, et
dans lequel la suspension aqueuse comprend moins de 5% en poids de silicate.
2. Procédé selon la revendication 1, dans lequel le sel minéral est choisi dans le groupe
constitué par des sels de métaux alcalins d'halogénures, de nitrates ou leurs mélanges.
3. Procédé selon la revendication 1, dans lequel le sel minéral est choisi dans le groupe
constitué par des sels de métaux alcalino-terreux d'halogénures, de nitrates ou leurs
mélanges.
4. Procédé selon la revendication 2, dans lequel le sel minéral est le chlorure de sodium.
5. Procédé selon l'une quelconque des revendications précédentes, dans lequel l'étape
consistant à ajouter le sel minéral augmente la conductivité ionique de la suspension
aqueuse d'au moins 3 milliSiemens.
6. Procédé selon la revendication 1, dans lequel la plage du tensioactif anionique est
1% à 50%, plus préférablement 5% à 20% en poids.
7. Procédé selon la revendication 1, dans lequel la plage d'aluminosilicate de sodium
est 1% à 50%, plus préférablement 5% à 30% en poids.
8. Procédé selon la revendication 1, dans lequel la plage du sel minéral est 1% à 50%,
plus préférablement 1% à 10% en poids.
9. Procédé selon l'une quelconque des revendications précédentes, dans lequel la suspension
est séchée dans une étape de séchage par atomisation.
10. Poudre séchée par atomisation comprenant :
(a) au moins un tensioactif,
(b) 2% à 80% en poids d'aluminosilicate,
(c) 1% à 20% en poids d'un sel minéral choisi dans le groupe constitué par des sels
de métaux alcalins, de métaux alcalino-terreux, ou leurs mélanges, d'halogénures,
de nitrates, ou leurs mélanges, et
(d) moins de 2% en poids de silicate.
11. Poudre séchée par atomisation selon la revendication 10, comprenant :
(a) au moins 5% en poids de tensioactif,
(b) 10% à 50% en poids d'aluminosilicate,
(c) 2% à 10% en poids d'un chlorure de métal alcalin, de préférence de sodium, et
(d) moins de 2% en poids de silicate.