Note: Descriptions are shown in the official language in which they were submitted.
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PROCESS FOR MAKING DE7.'ERGENT COMPOSITIONS
The present invention relates to a process for making
detergent compositions
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
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
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2
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.
W094/05761, published on 17th March 1994, describes a final
product densification step wherein substantially all of the
product is sprayed with nonionic surfactant and coated with
zeolite. Good dispensing and dissolving properties are
claimed.
However it has now been found that even further
improvements in dispensing and dissolving properties can be
achieved if the nonionic surfactant and zeolite coating is
applied only to selected parts of the detergent
composition, rather than to the detergent composition as a
whole.
The object of the invention is to provide an improved
process for making a detergent composition comprising
anionic surfactant, nonionic surfactant and non-surfactant
additives.
Summary of the Invention
The object of the present invention is achieved by a
process for making a detergent composition comprising
anionic surfactant, nonionic surfactant and non-surfactant
additives, the process comprising the steps of:
(i) mixing together at least two non--surfactant additives
to form a premix;
(ii) spraying all of the nonionic surfactant on to the
premix; subsequently applying a finely divided particulate
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3
material to the premix to form a first intermediate
particle; and
(iii) subsequently mixing the first intermediate particle
with a second intermediate spray-dried or agglomerated
particle, wherein the second intermediate spray-dried or
agglomerated particle comprises from 20 to 40% by weight of
anionic surfactant, and is free of nonionic surfactant.
Detailed Description of the Invention
In a preferred embodiment of the process the first
intermediate particle is formed by:
(a) mixing together at least two non-surfactant additives
to form a premix; and
(b) increasing the mean particle size of the premix by
spraying nonionic surfactant on to the premix arid applying
a finely divided particulate material, preferably
aluminosilicate.
In a still further preferred embodiment of the process the
first intermediate particle is formed by:
(a) mixing together at :least two non-surfactant additives
to form a premix;
(b) spraying nonionic surfactant on to the premix wherein
the ratio of nonionic surfactant to premix is at least
1:25;
(c) applying a first arnount of finely divided particulate
material, wherein the ratio of the first amount of finely
divided particulate material to nonionic surfactant applied
in step (b) is less than 1:1;
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(d) increasing the mean particle size of the premix by
mixing; and
(e) applying a second amount of finely divided particulate
material, wherein the second amount of finely divided
particulate material to nonionic surfactant applied in step
(b) is greater than 1:1.
The process of the invention results in a narrow particle
size distribution with a sharply defined mean. Preferably
the mean particle size is 800 to 1200 micrometers, and the
particle size distribution has a standard deviation of less
than 100 micrometers. More preferably the mean particle
size is from 900 to 1100 micrometers, and the particle size
distribution has a standard deviation of less than 50
micrometers.
Non-surfactant additives may include any detergent
additives such as bleach, especially perborate or
percarbonate; inorganic salts, especially carbonate,
bicarbonate, silicate, sulphate, or citrate; chelants,
enzymes.
Preferably the first intermediate particle comprises less
than 5% by weight of anionic surfactant, more preferably
the first intermediate particle comprises less than 1% by
weight of anionic surfactant.
Finely divided particulate materials useful herein include
aluminosilicates having the empirical formula:
Mz ( zA102 ) y ] ~ x H20
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.
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Useful aluminosilicate ion exchange materials are
commercially available. These a.luminosilicates 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-A-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 .
Nal2 [ (A102) 12 (SiO2) 12 l ~ x H20
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 abovut 200 mg equivalent of
CaC03 water hardness/g of alumi:nosilicate, 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
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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 (0.138
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 (0.398
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).
While any nonionic surfactant may be usefully employed in
the present invention, two families of nonionics have been
found to be particularly useful. These are nonionic
surfactants based on alkoxylated (especially ethoxylated)
alcohols, and those nonionic surfactants based on amidation
products of fatty acid esters and N-alkyl polyhydroxy
amine. The amidation products of the esters and the amines
are generally referred to herein as polyhydroxy fatty acid
amides. Particularly useful in the present invention are
mixtures comprising two or more nonionic surfactants
wherein at least one nonionic surfactant is selected from
each of the groups of alkoxylated alcohols and the
polyhydroxy fatty acid amides.
Suitable nonionic surfactants 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
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yield a water-soluble compound having the desired degree of
balance between hydrophilic and hydrophobic elements.
Particularly preferred for use in the present invention are
nonionic surfactants such as 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 an average of up 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 2 to 10 moles of ethylene oxide per mole of alcohol;
and condensation products of propylene glycol with ethylene
oxide. Most preferred are condensation products of alcohols
having an alkyl group containing from about 12 to 15 carbon
atoms with an average of about 3 moles of ethylene oxide
per mole of alcohol.
It is a particularly preferred embodiment of the present
invention that the nonionic surfactant system also includes
a polyhydroxy fatty acid amide component.
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-(R1)-
CHz (CH20H) 4-CHZ-OH, where Rl is typically alkyl, e.g.
methyl group; and the preferred ester is a C12-C20 fatty
acid methyl ester.
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Methods of manufacturing polyhydroxy fatty acid amides have
been described in WO 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-methyl
glucamine is reacted with a C12-C20 methyl ester.
Other nonionic surfactants which may be used as components
of the surfactant systems herein include ethoxylated
nonionic surfactants, glycerol ethers, glucosamides,
glycerol amides, glycerol esters, fatty acids, fatty acid
esters, fatty amides, alkyl polyglucosides, alkyl
polyglycol ethers, polyethylene glycols, ethoxylated alkyl
phenols and mixtures thereof.
The second intermediate particle of the present invention
comprises anionic surfactant. The second intermediate
particle may be made by any process including spray drying,
flaking, prilling, extruding, pastillating, and
agglomeration. Agglomeration processes for making anionic
surfactant particles have been disclosed in the prior art
in, for example, EP-A-0 508 543, EP-A-0 510 746, EP-A-0 618
289 and EP-A-0 663 439. An essential feature of the
invention is that no nonionic surfactant is sprayed on to
the surfactant agglomerate stream.
Non-limiting examples of anionic surfactants useful herein
include the conventional C11-C18 alkyl benzene sulfonates
("LAS") and primary, branched-chain and random C10-C20
alkyl sulfates ("AS"), the C10-C18 secondary (2,3) alkyl
sulfates of the formula CH3 (CH2)x (CHOS03-M+) CH3 and CH3
(CH2)y(CHOS03-M+) CH2 CH3 where x and (y+1) are integers of
at least about 7, preferably at least about 9, and M is a
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water-solubilizing cation, especially sodium, unsaturated
sulfates such as oleyl sulfate, the C10-C18 alkyl alkoxy
sulfates ("AExS", especially EO 1-7 ethoxy sulfates), C10-
C18 alkyl alkoxy carboxylates (especially the EO 1-5
ethoxycarboxylates), the C10-C18 glycerol ethers, the C10-
C18 alkyl polyglycosides and their corresponding sulfated
polyglycosides, the C12-C18 alpha-sulfonated fatty acid
esters, methyl ester sulphonat~e and oleoyl sarcosinate.
Finally the surfactant agglomerates and layered granular
additives are mixed, optionally with additional additives
to form a finished detergent composition.
The various mixing steps of thcs present invention may be
carried out in any suitable mixer such as the Eirich~,
series RV, manufactured by Gust=au Eirich Hardheim, Germany;
Lodige°, series FM for batch mixing, series Baud KM for
continuous mixing/agglomeration, manufactured by Lodige
Machinenbau GmbH, Paderborn Ge~__~many; Drais~ T160 series,
manufactured by Drais Werke GmbH, Mannheim Germany; and
Winkworth° RT 25 series, manufactured by Winkworth
Machinery Ltd., Berkshire, Eng:Land; the Littleford Mixer,
Model #FM-130-D-12, with internal chopping blades and the
Cuisinart Food Processor, Mode=L #DCX-Plus, with 7.75 inch
(19.7 cm) blades. Many other mixers are commercially
available for both batch and continuous mixing.
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Examples
Example Example Example Example Example
1 2 3 4 5
Sodium carbonate 3 2 2 7.8
Sodium citrate - - - - 10
Sodium - - - - 10
bicarbonate
Percarbonate 20 16 16 - -
Perborate - - - 18 -
Enzymes 1.7 2.2 2.2 1 2
Nonionic 4 13 19 20 20
surfactant
particles
Hydroxy ethylene 1 1 1 -
diphosphonic acid
Tetraacetyl 6 4.7 4.7 4 -
ethylene diamine
Antifoam particle 2.8 1 1 - -
Layered silicate 15 12 12 - -
Sodium silicate - - - 2 3
(2.0R)
Sodium sulphate - - - - 5
Cationic 5 - - - -
surfactant
particles
Brightener - - - 0.2 -
58.5 51.9 57.9 53 50
All percentages expressed by weight of finis hed product
are
unless otherwise ated.
st
Nonionic surfactantparticles contained 15 parts alcohol
ethoxylate with average 5 EO grou ps per le, AE5,15
an of mo
parts of polyhydroxy fatty 60 parts zeolite,5
acid amide,
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parts fatty acid and 5 parts water, and were made according
to the process disclosed in EP-A-0 643 130.
Antifoam particles contained lc. parts silicone oil, 70
parts starch and 12 parts hydrogenated fatty acid / tallow
alcohol ethoxylate (TAE80), anal were made according to the
process disclosed in EP-A-0 495 345.
Layered silicate is SKS-6° supplied by Hoechst
Cationic surfactant particles contained 30 parts alkyl
dimethyl ethoxy ammonium chloride, 60 parts sodium
sulphate, 5 parts alkyl sulphate and 5 parts water and were
made according to the process disclosed in EP-A-0 714 976.
Brightener is Tinopal CDX° supplied by Ciba-Geigy.
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Example 1
The additives shown under Example 1 in the previous table
were mixed together and found to have an average particle
size of 440 micrometers.
6.5% of nonionic surfactant (alcohol ethoxylate with an
average of 5 EO groups per mole, AE5) at 35°C was sprayed
onto the additive mixture in a concrete mixer using a two-
fluid spray nozzle. 5% of zeolite A was added into the
concrete mixer over a period of 1 minute. The mixer then
continued to operate without further addition of zeolite
for a further one and a half minutes. Finally a further 8%
of zeolite was added over a period of 1 minute.
The product in the concrete mixer had an average particle
size of 1020 micrometers.
An anionic surfactant particle was then added to the
concrete mixer at a level of 22%. The anionic surfactant
particle contained 28 parts linear alkyl benzene
sulphonate, 12 parts tallow alkyl sulphate, 30 parts
zeolite, 20 parts carbonate and 10 parts water, and had an
average particle size of 850 micrometers.
The finished product had an average particle size of 960
micrometers.
Example 2
The additives shown under Example 2 in the previous table
were mixed together and found to have an average particle
size of 390 micrometers.
6.5% of nonionic surfactant (AE5) at 35°C was sprayed onto
the additive mixture in a concrete mixer using a two-fluid
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spray nozzle. 4% of zeolite A w,as added into the concrete
mixer over a period of 1 minute. The mixer then continued
to operate without further addition of zeolite for a
further one minute. Finally a further 9% of zeolite was
added over a period of 2 minutes.
The product in the concrete mixE_r had an average particle
size of 1080 micrometers.
An anionic surfactant particle was then added to the
concrete mixer at a level of 28.,6%. The anionic surfactant
particle contained 28 parts linear alkyl benzene
sulphonate, 12 parts tallow alkyl sulphate, 30 parts
zeolite, 20 parts carbonate and 10 parts water, and had an
average particle size of 850 micrometers.
The finished product had an average particle size of 1030
micrometers.
Example 3
The additives shown under Example 3 in the previous table
were mixed together and found to have an average particle
size of 390 micrometers.
6.5% of nonionic surfactant (AE5) at 35°C was sprayed onto
the additive mixture in a concreae mixer using a two-fluid
spray nozzle. 7% of zeolite A wa.s added into the concrete
mixer in a single step.
The product in the concrete mixer had an average particle
size of 555 micrometers.
An anionic surfactant particle was then added to the
concrete mixer at a level of 28.60. The anionic surfactant
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particle contained 28 parts linear alkyl benzene
sulphonate, 12 parts tallow alkyl sulphate, 30 parts
zeolite, 20 parts carbonate and 10 parts water, and had an
average particle size of 410 micrometers.
The finished product had an average particle size of 520
micrometers.
Example 4
The additives shown under Example 4 in the previous table
were mixed together.
6% of nonionic surfactant (AE5) at 35°C was sprayed onto
the additive mixture in a concrete mixer using a two-fluid
spray nozzle. 13% of zeolite A were added into the concrete
mixer in discrete portions, 1% at a time.
The product in the concrete mixer had an average particle
size of 1000 micrometers.
A spray dried powder was then added to the concrete mixer
at a level of 28%. The spray dried particle contained 20
parts linear alkyl benzene sulphonate, 5 parts polyacrylate
polymer, 5 parts of chelant, 30 parts zeolite, 30 parts
sulphate and 10 parts water, and had an average particle
size of 1000 micrometers.
The finished product had an average particle size of 1000
micrometers.
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Example 5
The additives shown under Example 5 in the previous table
were mixed together.
7% of nonionic surfactant (AE5) at 35°C was sprayed onto
the additive mixture in a concrete mixer using a two-fluid
spray nozzle. 13% of zeolite A were added into the concrete
mixer in discrete portions, 1% at a time.
The product in the concrete mixer had an average particle
size of 1050 micrometers.
A spray-dried granule was then added to the concrete mixer
at a level of 30%. The spray dried particle contained 20
parts linear alkyl benzene sulp.honate, 5 parts polyacrylate
polymer, 5 parts of chelant, 30 parts zeolite, 30 parts
sulphate and 10 parts water, and had an average particle
size of 1000 micrometers.
The finished product had an average particle size of 1020
micrometers.
