Note: Descriptions are shown in the official language in which they were submitted.
W094/0576t 2 1 ~ 3 ~ ~ PCT/US93/081~1
Process for Making High Density Granular Detergent
and Compositions made by the Process
BACKGROUND OF THE INVENTION
There is a trend amongst commercially available granular
detergents towards higher bulk densities. This gives
benefits both for consumer convenience and for reduction
of packaging materials.
Many of the prior art attempts to move in this direction
have met with problems of poor solubility properties
arising from low rate of dissolution or the formation of
gels. A consequence of this in a typical washing process
can be poor dispensing of the product, either from the
~ dispensing drawer of a washing machine, or from a dosing
device placed with the laundry inside the machine. This
poor dispensing is often caused by gelling of particles
which have high levels of surfactant upon contact with
WO94/05761 PCT/US93/081~1
?~ 43~28 2
water. The gel prevents a proportion of the detergent
powder from being solubilised in the wash water which
reduces the effectiveness of the powder. Another adverse
consequence arises even if the powder is well dispensed
and dispersed in the washing water if it does not
dissolve rapidly. The wash cycle has a limited duration
during which the detergent can act upon the laundry. If
the cleaning action is delayed because the powder is slow
to dissolve, this, too, will limit the effectiveness of
the powder.
The process engineer and formulator have frequently found
that the need for good dispensing and the need for good
dissolution rate have placed conflicting demands upon
them. The solution has generally been to find a
compromise which gives adequate dispensing and adequate
dissolution rate. For example, poor dispensing of high
bulk density granular detergents is often associated with
surfactant rich particles having a high specific surface
area, either due to high porosity or a small particle
size (especially "fines"). However, decreasing the
porosity and/or increasing the average particle size
cause the dissolution rate to decrease.
Various methods for increasing bulk density are described
in the prior art - in many cases by using processes which
densify spray dried powders.
EP 184794 published on 18th June, 1986 (Henkel) describes a
process of loading an adsorbant carrier with nonionic
surfactant in a Loedige mixer which increases the bulk
density. The carrier is typically prepared by spray drying.
EP 327963 published on 16th August, 1989 (Henkel) describes
a basic post tower densification process in which the spray
dried component is pulverised prior to reagglomerating in a
granulation step.
WO94~05761
PCT/US93/08]~1
21~362~
EPA 367339 published on 9th May, l990 (Unilever) describes
a two-stage agglomeration process.
Even more recently processes have been developed whereby a
spray drying step has been completely eliminated. This has
been achieved by making particles which comprise
surfactants and builders by, for example extrusion or
agglomeration of viscous pastes.
However all of the prior art processes suffer either from
the presence of very small particles (fines) which tend to
gel and cause poor dispensing properties, or from the
presence of large, low porosity particles which overcome
the dispensing problem, but which are slow to dissolve in
the wash process.
It is the aim of the present invention to provide a
detergent composition that has three key properties:
i) a high bulk density
ii) good dispensing properties
iii) and dissolves rapidly.
This has been achieved by firstly dry mixing most (or all)
of the components of the finished detergent composition in
a granular form, and subsequently increasing the bulk
density by spraying on a liquid into one or more rotating
drums or mixers.
It is an essential feature of the present invention that
~ the initial particles must be granular (not dust), and they
are not passed through a pulverisation step. This is key to
~ achieving the benefits in dispensing properties.
It is also an essential feature of the present invention
that the mean particle size of the granular particles of
WO94/05761 PCT/~S93/08151
2~ 4 _,
the finished product should not be so great that the rate
of dissolution is slow.
SUMMARY OF THE INVENTION
A process in which the bulk density of a particulate
detergent material is increased starting from an initial
bulk density of at least 600g/l, by spraying a liquid on to
the particles and dusting with a fine powder in one or more
rotating drum(s) or mixer(s),
characterised in that the particulate detergent material
initially has a mean particle size greater than 400
micrometers, and that the increase in the mean particle
size during the process is not greater than 60%.
The invention also discloses a detergent composition having
excellent dispensing and dissolving properties.
DETAILED DESCRIPTION OF THE INVENTION
It is the aim of the present invention to provide a
detergent composition that has three key properties:
i) a high bulk density
ii) good dispensing properties
iii) and dissolves rapidly.
This has been achieved by firstly dry mixing most (or all)
of the components of the finished detergent composition in
a granular form, and subsequently increasing the bulk
density by spraying on a liquid into one or more rotating
drums or mixers.
WO94/05761 PCT/US93/081~1
2143628
The required properties are achieved by mixing most (or
all) of the detergent components in the form of granular
powders, in order to give a mixed particulate material
having a defined mean particle size and bulk density. The
bulk density is then further increased by spraying a
liquid, and dusting with a finely particulate flow aid in
one or more rotating drums or mixers in order to "round
off" the particles by filling pores and surface
irregularities.
It is an essential feature of the present invention that
the powder at the inlet of the rotating drums/mixers is in
a granular form (with little or no fines), and not
pulverised as a dust. This feature gives the dispensing
benefits (because the absence of fine powder/dust avoids
gel formation upon contact with water).
Preparation of the Mix of Granular Components
The granular components used in the present invention are
made from a wide range of ingredients useful for their
detergency which are chosen according to the demands of the
product formulator. Suitable ingredients are described
below.
Surfactants
Surfactants are selected from the group consisting of
anionic, zwitterionic, ampholytic and cationic surfactants,
and mixtures thereof. Anionic surfactants are preferred.
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
W094/0576] PCT/US93/081S1
2l4362~
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 l0 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 (C8-Cl8 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.
Other anionic surfactants herein are the sodium alkyl
glyceryl ether sulfonates, especially those ethers of
WO94/05761 PCT/US93/08151
7 21~ 3 G2 8
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 qroups 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
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.
Also useful are the sulphonation products of fatty
acid methyl esters containing a alkyl group with from 10 to
20 carbon atoms. Preferred are the C16-18 methyl ester
sulphonates (MES)
Water-soluble nonionic surfactants are also useful as
secondary surfactant in the compositions of the invention.
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
W094/05761 PCT/US93/08151
~4~6~8
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.
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.
Other useful nonionic surfactants are based upon
natural renewable sources such as glucose. Alkyl
polyglucoside (APG), preferably those containing from 10 to
20 carbon atoms and an average of from 1 to 4 glucose
groups. Also useful are nonionic surfactants based on
glucose amides which contain an alkyl group with from 10 to
20 carbon atoms, for example tallow N-methyl glucamine.
Polyhydroxy fatty acid amides may be produced 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(CH20H)4-CH2-OH and the preferred
ester is a C12-C20 fatty acid methyl ester. Most preferred
W094/05761 214 ~ ~ 2 ~ PCT/~S93/08151
,~
is the reaction product of N-mehtyl glucamine with C12-C20
fatty acid methyl ester.
Methods of manufacturing polyhydroxy fatty acid amides
have been described in W0 92 6073, 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-mehtyl
glucamine is reacted with a C12-C20 mehtyl 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 preferred in the present invention, such as those
comprising N-methyl glucamide and C12-C14 alcohols with an
average of 3 ethoxylate groups per molecule.
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 lO 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.
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
W094/OS761 PCT/~S93/08151
~ 436~ 10
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 18 carbon atoms.
Particularly preferred surfactants herein include
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 water-soluble
quaternary ammonium compounds of the form R4R5R6R7N+X-,
wherein R4 is alkyl having from 10 to 20, preferably from
12-18 carbon atoms, and Rs, R6 and R7 are each Cl to C7
alkyl preferably methyl; X~ is an anion, e.g. chloride.
Examples of such trimethyl ammonium compounds include C12_
14 alkyl trimethyl ammonium chloride and cocalkyl trimethyl
ammonium methosulfate.
Specific preferred surfactants for use herein include:
alpha-olefin sulphonates; triethanolammonium Cl1-C13
alkylbenzene sulfonate; alkyl sulfates, (tallow, coconut,
WO94/0~761 1 4 3 62 8 PCT/US93/081~1
~ w
1t
palm, synthetic origins, e.g. C4s, etc.); sodium alkyl
sulfates; methyl ester sulphonate; 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 from 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.
Deterqency Builders
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
formula
NaZ[(AlO2)Z (SiO2)y] xH2O
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(zAlo2 YSiO2)
wherein M is sodium, potassium, ammonium or substituted
ammonium, z is from about 0.5 to about 2 and y is 1, said
W O 94/05761 PC~r~US93/08151
2 1 ~ 3 6 Z 8 12
material having a magnesium ion exchange capacity of at
least about 50 milligram equivalents of CaCO3 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.
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 CaCO3 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/gallontminute/gram/gallon, based on calcium ion
hardness. Optimum aluminosilicate for builder purposes
13 ~ ~ ~3 ~2~ ~
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.
CaCO3/g (12 mg Mg++/g) and a Mg++ exchange rate of at least
about l 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 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, and Zeolite X. In an
especially preferred embodiment, the crystalline
aluminosilicate ion exchange material has the formula
Nal2 [ (A102) 12 (Sio2) 12] ' XH2~
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.
14 '~
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 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.
Specific examples of inorganic phosphate builders are
sodium and potassium tripolyphosphate, pyrophosphate,
polymeric metapohosphate 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; 3,422,137i 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
SiO2 to alkali metal oxide of from about 0.5 to about 4.0,
preferably from about 1.0 to about
WO94/0~761 PCT/US93/081~1
214362~
~., ~
2.4. Layered silicates of the type manufactured by Hoechst
AG, Frankfurt, Germany and sold under the trade name SKS-6
are also useful in the present invention.
As mentioned above chemical ingredients normally used
in detergents such as zeolite, carbonate, silica, silicate,
citrate, phosphate, perborate, percarbonate etc. and
process acids such as starch, can be used in preferred
embodiments of the present invention.
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 maleic and acrylic acids. Molecular weights
for such polymers vary widely but most are within the range
of 2,000 to l00,000.
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 maleic
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
W094/0576~ 2~ PCT/US93/08151
36
16
speckles, bleaching agents and bleach activators, suds
boosters or suds suppressors, antitarnish and anticorrosion
agents, soil suspending agents, soil release agents,
softening clays, dyes, fillers, optical brighteners,
germicides, pH adjusting agents, nonbuilder alkalinity
sources, hydrotropes, enzymes, enzyme-stabilizing agents,
chelating agents and perfumes.
Optical brighteners may be incorporated either
directly into one (or more) of the granular components, or
a solution or slurry of optical brightener may be sprayed
into the rotating drum or mixer during the process of the
present invention.
Particulate suds suppressors may also be incorporated
in the finished composition by mixing according to the
present invention. Preferably the suds suppressing activity
of these particles is based on fatty acids or silicones.
Mixing
The granular components may be prepared and mixed by any
conventional means. Typically the mixing process may be
carried out continuously by metering each component by
weight on to a moving belt, and blending them in a rotating
drum or mixer. The mean particle size of the mixed granular
components must be greater than 400 micrometers, and the
bulk density must be greater than 600 g/l.
In order to achieve these physical characteristics of the
granular component mix, and in order to maintain the
dispensing benefits of the present invention, it is
preferred that the individual granular components are
prepared by processes other than spray drying such as
agglomeration, compaction, encapsulation etc. One
particularly preferred process of agglomerating high active
surfactant pastes with builders and other powders is
W094/0~76t PCT/US93/081~1
~I 43628
17
described in the Applicants' co-pending European
Application No. EPA 510746 published on 28th October 1992.
It is preferred that little or none of the granular
components is prepared by spray drying of slurries
comprising organic surfactants. Such spray dried components
generally require a pulverisation step in order to prepare
a high bulk density component. In general it is preferred
that there is no granular component which has been prepared
by spray drying, and which comprises an organic surfactant,
which is present at a level of greater than 10% by weight
of the finished product.
The Drum/Mixer Process
The process of the present invention is carried out in one
or more drum(s) or mixer(s) in which the bulk density of
the product is increased without losing the benefits of
good dispensing properties and rapid rate of dissolution
Without wishing to be bound by theory the granular
particles are rolled within the drum/mixer in the "wet"
state causing them to become rounded and increasingly
regular in shape (ie more spherical) and particle size.
This results in a finished composition with a density of at
least 750 g/l, preferably greater than 800 g/l.
Suitable equipment includes various rotating drums or
mixers with a rotating shaft, such as ribbon blenders or
low shear mixers supplied by Lodige Machinenbau GmbH,
Paderborn, Germany (especially those mixers supplied under
the Trade Mark Loedige KM). Such a low shear mixer
comprises mixing tools, often of the "ploughshare" type
mounted on to the rotating shaft. If a low shear mixer is
used, the rotational speed of the shaft should be less than
250 rpm.
WO94/05761 ~ 3 ~ 2 8 PCT/US93/081~t
18
It is preferred that the liquid sprayed on to the mix of
granular components comprises nonionic surfactant. Useful
nonionic surfactants have been described hereinabove.
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.
Other liquid ingredients may also be sprayed on to the mix
of granular components either separately or premixed.
Typically perfume and slurries of optical brightener may be
sprayed. Although any optical brightener may be added in
this way, it has been found that Colour Index Fluorescent
Brightener number 351 (as published by the Society of Dyers
-and Colourists and the American Association of Textile
Chemists and Colourists) gives particular benefits of
colour stability.
High Speed Cutters or Choppers may be advantageously used
in order to prevent large balls of product from forming
when wet, but pulverisation of the powders (which could
occur when they are dry) should be avoided. The high speed
cutters or choppers may be mounted on a shaft which is
oriented radially with respect to the wall of the mixer,
and preferably the shaft rotates at a speed greater than
l000rpm.
The process must be differentiated from a more conventional
agglomeration process. This can clearly be seen by
observing the increase in mean particle size from beginning
to end of the process. In the present invention, the mean
particle size does not increase by more than about 60% of
the initial mean particle size.
Preferably it does not increase by more than 40%, and more
preferably it does not increase by more than 20% of the
initial mean particle size.
WO94/0~761 PCT/US93/08151
2I ~ ~628
".~ 19
The term mean particle size as defined herein is calculated
~ by sieving a sample of the composition into a number of
fractions (typically 5 fractions) on a series of Tyler
- sieves. The weight fractions thereby obtained are plotted
against the aperture size of the sieves. The mean particle
size is taken to be 'he theoretical aperture size through
which 50% by weight of the sample would pass.
According to the present invention finely divided flow aid
(such as zeolites, carbonates, silicates, silicas) is added
to the mix of granular components, preferably towards the
end of the process. These dusting agents are the only
components which are added as a dust. It is therefore
particularly important that the flow aids selected do not
gel upon contact with water (as some forms of finely
divided silicates would). This careful selection of finely
divided flow aid enables the bulk density to be further
increased without losing the benefits of the good
dispensing properties.
Finished Compositions
The present invention provides a method of making detergent
compositions with very high bulk densities, which also have
the characteristics of excellent dispensing properties and
a rapid rate of dissolution. This method is very flexible
with regard to the formulations that can be processed.
Indeed any chemical that can be incorporated into a
granular particle may be incorporated into a high bulk
density composition by the process defined hereinabove.
A particularly preferred embodiment of the present
invention is a composition which has a bulk density of at
least 750g/l, preferably at least 800g/l which comprises;
a) From 5% to 20% of organic surfactant
b) From 5~ to 20~ of sodium aluminosilicate
W094/05761 PCT/US93/08151
3~
and which has a dispensing residue of less than 30% when:
a 150g sample of the detergent composition is poured into a
drawer of a Zanussi (TM) shower-type dispenser, and 4
litres of water at a temperature of 20~C is passed through
the said drawer from the nozzles of the dispenser at a rate
of 2 litres/minute, after which the portion of the
detergent composition remaining in said dispensing drawer
is weighed, and the resulting weight expressed as a
percentage of the initial 150g sample and averaged over at
least 5 repetitions of the test, the resulting percentage
being the dispensing residue;
and which has a rate of dissolution of the detergent
composition which is at least 50% of the
sulphate/sulphonate salts passing into solution in less
than 3 minutes when a lOg sample is dissolved in 1 litre of
distilled water at a temperature of 20~C in a 1 litre Sotax
cup, and with a Sotax stirring propellor no. 3990-2
rotating at 200rpm about a vertical axis, the bottom of the
said stirring propellor being located 33mm above the bottom
of the cup.
Details of the recommended test methods are given in
Section B.
Most preferred compositions comprise mixed anionic
surfactant sytems having a Krafft temperature less than
40~C in order to achieve a good rate of dissolution at mean
particle size of 550-750micrometers.
Furthermore most preferred compositions are nil-phosphate
and nil-linear alkyl benzene sulphonate (nil-LAS) for
environmental reasons.
WO94/05761 PCT/US93/08151
~ 21 l36~8
EXAMPLES
- EXAMPLE I
A mixture of granular raw materials is prepared according
to the following composltion :
% by weiqht
Anionic surfactant agglomerate 30.0
Layered silicate compacted granule 17.7
Percarbonate 24.7
TAED agglomerate 9.2
Suds suppressor agglomerate 2.2
Perfume encapsulate 0.2
Granular soil release polymer 0.6
Granular dense soda ash 8.6
Granular acrylic-maleic copolymer 3.2
3.6
Enzymes
100
WO94/05761 PCT/US93/08151
~43 22 '~
The anionic surfactant agglomerate is prepared by
agglomeration of a 78% active C45AS/C35A3S 80:20 paste and
a phosphonate solution (35%) onto a powder mixture
containing zeolite / carbonate / MgS04 / CMC at ratios
17/13/1/1 in a high shear mixer.
44 parts of the paste/phosphonate are mixed with 66 parts
of the powder mixture.
The wet agglomerate is dried in a fluid bed dryer to an
e~uilibrium relative humidity of about 12% at 20~C. The
final agglomerate contains 30% anionic surfactant and 2%
phosphonate and has an average particle size of about 500mm
with less than 5% through Tyler 65. The bulk density of
the agglomerates is 750g/L.
The mixture of the granular components has a bulk density
of 780g/L and a particle size distribution as follows :
Tyler Sieve no. micrometers % by weiqht
of Product on sieve
14 1180 2
850 13
425 68
212 97
100 150 99
WO94/05761 PCT/US93/08151
2I ~62~
23
The mean particle size of the mixture of granular
ingredients is about 525 micrometers.
The mixture of granular ingredients described above is
placed inside a 600L rotating drum that operates at 15 rpm.
A mixture of nonionic surfactant (C25E3) and a 20% aqueous
solution of optical ~rightener (Pinopal CBS-X Trade Name,
supplied by Ciba-Geigy) at ratios of 14:1 are sprayed onto
the granular mixture while operating the drum to a level of
7%. The spraying time is about 7 minutes.
Immediately afterwards, perfume is sprayed on at a level of
0.5% while rotating the drum. Then, without stopping the
rotation of the drum, zeolite is slowly added to the mixer
to a level of about 8%, taking about 2 minutes. Once the
addition of zeolite is finished, the mixer is allowed to
rotate for about 30 seconds and is then stopped. The
product is removed by opening the gate and further rotating
the drum for about 10 seconds.
The product has a density after 2 days ageing of 910g/L.
The particle size distribution is :
TYler Sieve no. micrometers % by weight
of product on sieve
14 1180 5
850 23
425 87
212 99
100 150 99.5
WO94/05761 PCT/US93/081~t
21 ~3 ~2~ 24 '~
The mean particle size of the product is about 640
micrometers. This represents an increase in mean particle
size of 22%.
The dispensing results of this product according to the
method described in Section B is
Dispensing residue (%)
2 L/min 24
3 L/min 2
The dissolution profile of the anionic surfactant measured
according to the method also described in Section B shows
the time for dissolution of 50% of the anionic surfactant
to be l.8 minutes.
EXAMPLE II
A mixture of granular raw materials is prepared according
to the following composition :
% by weight
Anionic surfactant agglomerate 53.3
Granular silicate 3.2
Granular dense soda ash ll.0
Granular sodium citrate 18.l
Granular acrylic-maleic copolymer 7.9
Suds suppressor agglomerate 2.0
Enzymes 4.S
100
W O 94/05761 PC~r/US93/08151
~ 21 13628
The anionic surfactant agglomerate is prepared via
agglomeration of a 78% active LAS/TAS/C35E3S 74:24:2 paste
onto a powder mixture containing zeolite / carbonate / CMC
at ratios of 20/10/1 in a high shear mixer. The wet
agglomerate is dried in a fluid bed dryer to an equilibrium
relative humidity of aout 12% at 20~C. The final
agglomerate contains 35% anionic surfactant, has an average
particle size of 600 micrometers with 8% particles smaller
than 212 micrometers and a bulk density of 740g/L.
The mixture of the granular components has a bulk density
of 740g/L and the following particle size distribution :
Tyler Sieve no. micrometers % by weight
of Product on sieve
14 1180 5
850 17
425 66
212 97
100 150 99
The mean particle size of the mixture of granular
ingredients is about 525 micrometers.
The above mixture (50kg) is placed in a Lodige FM 130 D.
The shaft rotates at about 160 rpm and the chopper speed is
3000 rpm. A mixture of nonionic surfactant (C45E7) and 20%
aqueous solution of an optical brightener at a ratio of
W094/0~761 PCT/US93/081~1
214362~ _,
26
14:1 are sprayed onto the mixture of powders while both the
shaft and the chopper are operated.
A total of 5.2kg of the li~uid mixture is added in an
interval of about 1 and a half minutes. Immediatly after,
0.3kg of perfume is also sprayed on. Then 5kg of finely
divided zeolite is added to the mixer. The addition time
is about 2 minutes and after addition, the unit is operated
without the chopper for another half a minute. The product
is discharged through the opening in the bottom of the
mlxer .
The density of the product after 2 days is 897g/L. The
particle size distribution is :
TYler Sieve no. micrometers % by weight
of product on sieve
14 1180 17
850 41
425 78
212 94
100 150 98
The mean particle size of the product is about 740
micrometers. This represents an increase in mean particle
size of about 40%.
The dispensing results of this product according to the
method described in Section B is
WO94/05761 PCT/US93/081~1
,~, 21~3628
Dispensing residue ~%)
2 L/min 14
3 L/min o
The dissolution profile of the anionic surfactant measured
according to the method also described in Section B shows
the time for dissolution of 50% of the anionic surfactant
to be l.O minutes.
COMPARATIVE EXAMPLE III
A mixture of granular raw materials is prepared according
to the following composition :
% bY weiqht
Anionic surfactant agglomerate 12.0
Blown powder 49.2
Silicate 3.2
Granular dense soda ash ll.0
Granular sodium citrate 18.l
Suds suppressor agglomerate 2.0
Enzymes 4.5
100
W094/0576l 3~2~ 28 PCI/US93/08151
The anionic surfactant agglomerate is prepared via dry
neutralisation of acid LAS onto a powder mixture containing
zeolite / carbonate at a ratio of 1/1 in a high shear
mixer. The agglomerate contains 30% anionic surfactant,
has an average particle size of 500 micrometers with 16%
particles smaller than 212 micrometers and a bulk density
of 740g/L.
The blown powder is made via spray-drying a mixture
containing:
% by weiqht
Anionic surfactant paste 40.0
Zeolite 44.0
Acrylic-maleic co-polymer 16.0
where the anionic surfactant paste is 50% surfactant active
and contains LAS and TAS at ratios 2.4 :1.
The mixture of the raw material components has a bulk
density of 670g/L and the following particle size
distribution:
TYler Sieve no. micrometers % bY weiqht
of Product on sieve
14 1180 4
850 11
425 33
212 64
100 150 86
WO94/05761 21 g 3 6~ 8 PCT/US93/0815t
29
The mean particle size of the mixture of ingredients is
about 370 micrometers.
The above mixture (50kg) is placed in a Lodige FM 130 D.
The shaft rotates at about 160 rpm and the chopper speed is
3000 rpm. A mixture of nonionic surfactant (C45E7) and 20%
aqueous solution of an optical brightener at a ratio of
14:1 are sprayed onto the mixture of powders while both the
shaft and the chopper are operated.
A total of 5.2kg of the liquid mixture is added in an
interval of about 1 and a half minutes. Immediatly after,
0.3kg of perfume is also sprayed on. Then 5kg of finely
divided zeolite is added to the mixer. The addition time
is about 2 minutes and after addition, the unit is operated
with the chopper for another 3 minutes. The product is
discharged through the opening in the bottom of the mixer.
The density of the product after 2 days is 847g/L. The
particle size distribution is :
TYler Sieve no. micrometers% bY weight
of ~roduct on sieve
14 1180 7
850 13
425 47
212 75
100 150 88
W094/05761 PCT/US93/08151
~ 43G~8 30
The mean particle size of the product is about 400
micrometers.
The dispensing results of this product according to the
method described in Section B is
DisPensinq residue (%)
2 L/min 102
3 L/min 84
The dissolution profile of the anionic surfactant measured
according to the method also described in Section B shows
the time for dissolution of 50% of the anionic surfactant
to be 0.8 minutes.
WO94/05761 PCT/US93/081~1
'- 21~36~8
31
Section B - Test Methods
Rate of Dissolution of Anionic Surfactants under Stressed
Conditions (Sotax Method)
EquiPment
l) Sotax cup (lL)
2) Distilled water
3) Electrical stirrer motor with variable speed (IKA-Werk
RW 20 DZM)
4) Stainless steel propeller stirrer (Sotax no 3990-2)
5) 6 disposable filter type units with pore size 0.22
micron (25 mm diam., Millex No. SLGSO25NB Millipore).
6) Plastic syringes (2 mL) and disposable needles (21x l~)
7) Sample collectors (15 mL glass tubes)
8) Set of Tyler sieves and sieving equipment (Rotap)
9) Thermostated bath
Sample PreParation
Take a representative sample of lOg of the detergent
composition.
Experimental Procedure
l) Place the cup containing l L of water (or desired
solution) in the bath at the desired temperature.
Allow the temperature of the water to reach that of the
bath.
2) Place the impeller in the cup at 33 mm from the bottom.
3) Prepare 5 syringes with a filter unit and a needle.
Prepare l syringe with needle without the filter.
4) Set the mixer speed to 200 r.p.m.
5) Quickly add lO g of the product to be tested. Start the
stopwatch.
6) Remove, at precise intervals of lO sec., 30 sec., l
min. , 2,5 min. and 5 min, about 2 mL samples with the
W094/0~761 PCT/US93/08151
2 ~3 6~ 32
syringes. For adequate sampling, the needle has to be +
4 cm below the surface of the liquid.
7) After taking the 5 min. sample, increase the speed of
the impeller to 300 r.p.m.
8) After 10 minutes take another sample through the filter.
9) Take a sample of the liquid with the syringe without
filter. The difference between the result of this and
the previous one is an indication of the solubility that
can be expected at this temperature. Care must be taken
that during this time, the system does not increase its
temperature due to the vigorous stirring action.
10) Carry out the analytical determination of the content
of active ingredient (CatS03 analysis or similar). When
using a turbidimetric end point indication for the
titration, care must be taken that there is no
interference in the unfiltered sample due to the
presence of insolubles.
11) Calculate the percent dissolved in each sample by
using the unfiltered sample as 100 % (by CatS03
analysis, even the undissolved surfactant will be
titrated).
12) Plot the percent dissolved versus time for the first
period of time (up to 5 min.). Calculate the percent
solubility at the experimental conditions from the
filtered sample at 10 min.
Dispensing under Stressed Conditions (Zanussi (TM) Method)
Equipment
1) DispenserZanussi shower type dispenser.
The mainwash compartment will be used.
2) Water City water.
3) Water Temperature 20+1~C.
WO94/0~761 21 '1~ ~8 PCT/US93/081~1
33
4) Water Flow 2 + 0.05 L per 60+1 seconds.
The test runs for 2 minutes. Calibrate the
water flow rate using a measuring cylinder
or similar receiver.
5) Sample Mass 150+0.5 g of the test product.
Experimental Procedure
l) Cali~rate the equipment for above operating conditions.
Ensure that the whole experimental rig is horizontal and
that none of the nozzles of the dispenser are blocked.
2) Weigh the required amount of product to be tested in a
cup. Ensure that the sample is representative of the
entire product (avoid segregation when filling the cup).
- 3) Weigh the dispenser drawer after ensuring that it is
properly dried.
4) Place a vertical positioning screen in the mainwash
section of the dispenser, so that it blocks the width of
the drawer at a distance of 12.5 cm from the end of the
drawer furthest from the water exit. Pour the product
into the dispenser between the vertical positioning
screen and the end of the drawer furthest from the water
exit. The powder should be poured in such a way as to
keep the powder surface as level as possible. Remove
the screen.
5) Place the dispenser drawer gently in its slot, ensuring
it is fully home.
6) Start water at the calibrated flow rate. Ensure that
water is flowing entirely in the mainwash compartment.
7) Stop the water flow after 2 minutes and wait until the
water drain from the drawer is completely stopped.
8) Remove the drawer from the slot and drain any excess
water by slight tilting of the drawer. Ensure that no
product falls from the drawer. There should be no water
in any other compartment of the drawer. If some water
PCT/~S93/081~1
34
is found, the system needs rechecking to ensure that all
the water flow goes in the mainwash compartment.
9) Weigh the dispenser drawer with total residues.
10) Repeat the determination at least 5 times.
11) Average the wet residues. The result is expressed in
%wt of the initial amount of dry product.
Accuracy and Assessment
Significant differences between products can be assessed
when the average percent residues differ in 10% or more. A
product is considered to show good dispensing profile if
under this stressed test is below 30% residue at 2 L/min
(and/or below 10% residue at 3 L/min).
