Note: Descriptions are shown in the official language in which they were submitted.
~093/18123 ~ PCT/US93/01790
2~3~17;~
HIGH ACTIVE DETERGENT PASTES
Field of the invention
The present invention relates to pumpable high active
surfactant pastes which are suitable for further processing
into detergent granules, and to a process for making such
pastes.
WO93/18123 2131~172 PCT/US93/01790
Backqround of the invention
Granular detergents have so far been principally
prepared by spray drying. In the spray drying process the
detergent components, such as surfactants and builders, are
mixed with as much as 35-50% water to form a slurry. The
slurry obtained is heated and spray dried, which is
expensive. A good agglomeration process, however, could be
less expensive.
There are many prior art nonspray-drying processes which
produce detergent granules. Most require neutralisation of
the anionic surfactant acid, immediately before, or in the
course of, a granulation step.
However, these processes have certain limitations. The
close coupling of the neutralization and granulation steps
considerably limits the range of processing conditions that
can be used. Furthermore, if the anionic surfactant chosen is
not stable in the acid form (eg. alkyl sulphate) it is
necessary to have close coupling of the sulph(on)ation with
the neutralization and granulation stages. This results in
considerable limitations in the logistics and/or design of
the facilities for these processes as well as an important
increase in complexity and difficulty of control systems for
the overall process.
The purpose of this invention is to provide a high
active anionic surfactant paste which has rheological
properties that make it suitable for pumping, storing,
transportation between manufacturing sites, and further
processing by agglomeration into high active detergent
particles. It is an important feature of the invention that
the granulation/agglomeration step is completely uncoupled
from the sulph(on)ation step.
~093/18123 ~ PCT/US93/01790
It has now been found that the addition of small amounts
of alkyl ethoxy sulphate greatly improves the rheological
characteristics of the surfactant paste.
GB2021141, published November 28 1979, discloses
surfactant paste compositions within a narrow concentration
range in the fluid lamellar ('G') phase.
GB2116200, published September 21 1983, discloses paste
compositions of up to about 40% by weight of anionic
surfactant containing ethoxylated surfactants as dissolution
aids, and forming agglomerates from these compositions.
EP 403148, published December l9 l990, describes high
active surfactant compositions containing less than 14%
water. The use of process aids to reduce viscosity of the
high active paste in a neutralisation loop is described.
Polyethylene glycol and ethoxylated nonionic surfactants are
disclosed as suitable process aids.
EP 399581, published November 28 l990, describes high
active surfactant compositions containing ethoxylated anionic
surfactants and ethoxylated nonionic surfactants.
Summar~ of the invention
The present invention relates to a detergent paste
composition comprising : from 50% to 94% by weight of an
anionic surfactant: from 1% to 30% by weight of an alkyl
ethoxy sulphate and from 5% to 35% by weight of water. The
paste has a viscosity greater than 10 Pa.s at a temperature
of 70-C and measured at a shear rate of 25 5-1. The present
invention also encompasses a process for making such a paste.
WO93/18123 2~1~2 PCT/US93/01790
Detailed descriPtion of the invention
The alkyl ethoxy sulphate herein has been found to act as a
rheology modifier and gives the anionic surfactant paste the
behaviour of a simple shear thinning fluid with a yield
point. Accordingly the very concentrated paste of the present
invention can be pumped with the certainty that it will not
thicken during processing.
THE SURFACTANT PASTE
Typically surfactant pastes in the form of concentrated
solutions can be described by non-Newtonian, shear thinning
rheology models with yield points. These pastes usually show
reduced viscosities at increased shear rates (see figure l).
Surprisingly, it has now been found that under certain
conditions of surfactant type, concentration, inorganic
content, unsulph(on)ated contents, temperature etc., these
pastes may show a rheology profile where, at certain shear
rates, the viscosity increases with the shear rate. This
phenomenon is referred to as shear thickening.
The presence of shear thickening in these pastes makes
the transportation, storage and handling in general, a very
difficult task. The possibility of the formation of these
shear thickened pastes during pumping and conveying can
result in considerable pressure drops and possible blockage
of lines. In order to make the transportation of these pastes
a robust operation, suitable for commercial application, it
is necessary to ensure the absence of shear thickening
behaviour and to turn the rheology of the paste into that of
a typical shear thinning fluid, with or without a yield
point.
This then makes it possible to completely decouple the
neutralisation and granulation steps of making the finished
W~93/18123 2 ~ 3 ~ 1 7 2 PCT/US93/01790
detergent granule. The paste can be stored between these two
steps, alternatively it can be transported between two
manufacturing sites. This means that the manufacturing
process is greatly simplified, and becomes much more
flexible.
PHYSICAL PROPERTIES OF THE PASTE
The paste has a high viscosity, greater than l0 Pa.s at
70~C when measured at a shear rate of 25s-l, but has
rheological characteristics that make it easily pumpable and
favour further processing by agglomeration. Preferably the
paste has a viscosity greater than 20 Pa.s at 70 C.
A process for making such a paste is also described
hereinafter.
The paste is made up of two main components, the anionic
surfactant (the "active" ingredient) and the alkyl ethoxy
sulphate (the "rheological modifier"). These components are
described in greater detail below.
THE ANIONIC SURFACTANT
The aqueous surfactant paste contains an organic
surfactant selected from the group of anionic surfactants,
and mixtures thereof. Surfactants useful herein are listed in
U.S. Pat. No. 3,664,961, Norris, issued May 23, 1972, and in
U.S. Pat. No. 3,9l9,678, Laughlin et al., issued December 30,
1975.
The paste includes a high concentration of anionic
surfactant, preferably about 56% to about 63% by weight of the
paste.
~S ';
,~ . ' , t ~
,. ', i ~ ', ~ ..
W093/18123 21311~ PCT/US93/01790
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 lO 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 prcauaed by
reducing the glycerides of tallow or coconut oi 7; and the
sodium and potassium alkyl benzene sulfonates _n which the
alkyl group contains from about 9 to about lS carbon atoms,
in straight or branched chain configuration, e.g., those of
the type described in U.S. Pat. Nos. 2,220,099 and 2,477,383.
Especially valuable are linear straight chain alkyl benzene
sulfonates in which the average number of carbon atoms in the
alkyl group is from about ll to 13, abbreviated as Cll-Cl3
LAS .
Other useful anionic surfactants herein include the
water-soluble salts of alpha-sulfonated fatty acid methyl
esters containing from about 6 to 20 carbon atoms in the
fatty acid group and from about l to lO carbon atoms in the
ester group; water-soluble salts of 2-acyloxy-alkane-l-
W093/18123 2 13~ 172 PCT/US93/01790
sulfonic acids containing from about 2 to 9 carbon atoms inthe acyl group and from about 9 to about 23 carbon atoms in
the alkane moiety; 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.
The preferred anionic surfactant pastes are mixtures of
linear or branched alkylbenzene sulfonates having an alkyl of
10-16 carbon atoms and alkyl sulfates having an alkyl of 10-
18 carbon atoms. These pastes are usually produced by
reacting a liquid organic material with sulfur trioxide to
produce a sulfonic or sulfuric acid and then neutralizing the
acid to produce a salt of that acid. The salt is the
surfactant paste discussed throuqhout this document. The
sodium salt is preferred due to end performance benefits and
cost of NaOH vs. other neutralizing agents, but is not
required as other agents such as KOH may be used.
Particularly preferred surfactants for use herein
include : sodium linear Cll-C13 alkyl benzene sulphonate; ~
olefin sulphonates, triethanol ammonium Cll-C13 alkyl benzene
sulphonate; alkyl sulphates (tallow, coconut, palm, synthetic
origins eg. C14-C15 etc.) methyl ester sulphonate and the
water soluble sodium and potassium salts of coconut and
tallow fatty acids.
Most preferred are sodium Cll-13 linear alkyl benzene
sulphonate, tallow alkyl sulphonate and mixtures thereof.
THE ALKYL ETHOXY SULPHATE
The rheology modifier in the paste is chosen from the
alkali metal, alkaline earth metal, ammonium or substituted
ammonium salts of alkyl ethylene oxide ether sulphates
(generally referred to as alkyl ethoxy sulphates), containing
from about 1 to about 7 units of ethylene oxide per molecule
and wherein the alkyl group contains from about 10 to 18
~.
' 93/18123 2 ~ 3 ~ 1 7 2 PCT/US93/01790
carbon atoms. The alkyl ethoxy culphate is present at a level
of preferably about 7~ to about 14~ by weight of the paste
Preferred are the sodium or potassium salts of alkyl
ethoxy sulphate containing from about 2 to about 4 units of
ethylene oxide.
Most preferred are products of the sulphation of
synthetic, branched Cl3-Cl5, Cl4-Cl5 or Cl2-Cl5 ethoxylated
alcohols with an average of about 3 units of ethylene oxide
per molecule.
The ratio of anionic surfactant to alkyl ethoxy sulphate
will vary according to the rheological behaviour of the
anionic surfactant chosen. The ratio may vary between 2:l
(for example, in the case where the anionic surfactant is
tallow alkyl sulphate), to 50:l (for example, in the case
where the anionic surfactant is a mixture of 75% LAS with 25%
tallow alkyl sulphate). A preferred ratio of 9:l is suitable
in the case where the anionic surfactant is Cl4-Cl5 alkyl
sulphate.
WATER CONTENT OF THE PASTE
The water content of the paste is between about 23~ and
about 35% by weight. A low water content is preferable in order
to be able to make high active detergent particles in the
granulation/agglomeration step.
OPTIONAL INGREDIENTS
Other ingredients commonly used in detergent
compositions can be included in the paste of the present
invention. These include additional surfactants, hydrotropes,
suds boosters or suds suppressors, antitarnish and
anticorrosion agents, soilsuspending agents, soil release
B agents, germicides, pH adjusting agents, enzyme stabilising
-
~093/18123 2131~72 PCT/US93/01790
agents, perfumes, polymers including polyacrylates, and
copolymers including copolymers of maleic and acrylic acids.
Additional surfactants may be selected from the groups
of anionic, zwitterionic, ampholytic, cationic and nonionic
surfactants.
Suitable anionic surfactants include alkyl
polyglucosides, alkyl glyceryl ethoxy sulphonates and alkyl
glucose amides.
Suitable nonionic surfactants include the polyethylene
oxide condensates of alkyl phenol, and 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
mole of alcohol.
Semipolar nonionic surfactants including amine oxides,
phosphine oxides, and sulphoxides are also suitable for use
in the paste.
Ampholytic surfactants including those derived from
secondary and tertiary amines, and zwitterionic surfactants
including those derived from aliphatic quaternary ammonium ,
phosphonium and sulphonium compounds may also be used.
THE PROCESS
The surfactant paste is preferably produced in a
continuous neutralisation system, for example a continuous
neutralisation loop available from the Chemithon Corporation,
Seattle, WA, USA. In a continuous neutralisation loop,
organic sulphuric/sulphonic acid and concentrated metal
hydroxide solution (greater than about 4~% by weight of the
hydroxide) are added to the loop where neutralisation takes
place. For this invention, alkali metal hydroxide solution,
WO93/18123 - ~ PCT/US93/01790
Z13~172
between 50% and 75% hydroxide is preferred with the higher
concentrations leading to less water in the final paste.
A separate stream of water may also be added to the
loop, or mixed with the metal hydroxide in order to achieve
the required water level in the finished paste.
The organic sulphuric/sulphonic acid for use in making
the surfactant paste preferably is made by a sulph(on)ation
process using SO3 in a falling film reactor. See "Synthetic
Detergents~, 7th Ed., A.S. Davidson and B. Milwidsky, John
Wiley and Sons, Inc., 1987, pages 151-168.
The alkali metal hydroxide is preferably present in
slight excess of stoichiometric amount necessary to
neutralise the organic sulphuric/sulphonic acid. However,
reserve (free) alkalinity should not exceed about 1.5% M2O
(where M is metal)otherwise the paste becomes difficult to
circulate because of high viscosity. If reserve alkalinity
drops below about 0.1%, the surfactant paste may not be
stable long term because of hydrolysis. It is therefore
preferred that reserve alkalinity, which can be measured by
titration with acid, of the paste in the neutralisation
system be between about 0.1% and 1.5%, more preferably
between 0.2% and 1.0%, most preferably between about 0.3% and
1.0%.
The organic sulphuric/sulphonic acid and alkali metal
hydroxide are put into the continuous neutralisation loop,
preferably at a high shear mixer in the neutralisation loop
so that they mix together as rapidly as possible.
The alkyl ethoxy sulphate can be added at any suitable
stage in the process, including post addition to the paste
after the neutralisation loop or even in a storage tank,
provided enough mechanical energy is provided to intimately
mix the alkyl ethoxy sulphate with the salt of the anionic
surfactant.
~093/18123 Z~3~172 PCT/US93/01790
A preferred embodiment of the invention is to add ~he
alkyl ethoxy sulphates directly into the neutralisation loop.
In this way the rheology benefits of the invention are
realised in the paste within the neutralisation loop and no
additional mixing stage is required later.
Another alternative is to sulphate the ethoxylated
alcohol at the same time as sulph(on)ation of the anionic
surfactant. Then both components can be neutralised together
in the neutralisation loop to give a paste of the required
composition.
UK'l'~ K PROCESSING OF THE PASTE
The paste of the invention can be processed into high
active detergent agglomerates by any conventional
granulation/agglomeration step. This is normally done by
agglomerating the paste upon mixing with a dry detergent
powder.
A highly attractive option in a preferred embodiment of
the present invention to further increase the concentration
of surfactant in the final particle, is accomplished by the
addition to a liquid stream containing the anionic surfactant
and/or other surfactant, of other elements that result in
increases in viscosity and/or melting point and/or decrease
the stickiness of the paste. In a preferred embodiment of
the process of the present invention the addition of these
elements can be done in line as the paste is pumped into the
agglomerator. Example of these elements can be various
powders, including zeolite, carbonate, silica, silicate,
citrate, phosphate, perborate etc. and process aids such a
starch.
W093/18123 2~ 311 72 12 PCT/US93/01790
POWDER STREAM
Although the preferred embodiment of the process of the
present invention involves introduction of the anionic
surfactant in via pastes as described above, it is possible
to have a certain amount via the powder stream, for example
in the form of blown powder. In these embodiments, it is
necessary that the stickiness and moisture of the powder
stream be kept at low levels, thus preventing increased
"loading" of the anionic surfactant and, thus, the production
of agglomerates with too high of a concentration of
surfactant. The liquid stream of a preferred agglomeration
process can also be used to introduce other surfactants
and/or polymers. This can be done by premixing the
surfactant into one liquid stream or, alternatively by
introducing various streams in the agglomerator. These two
process embodiments may produce differences in the properties
of the finished particles (dispensing, gelling, rate of
dissolution, etc.), particularly, if mixed surfactants are
allowed to form prior to particle formation. These
differences can then be exploited to the advantage of the
intended application for each preferred process.
It has also been observed that by using the presently
described technology, it has been possible to incorporate
higher levels of certain chemicals (e.g. nonionic, citric
acid) in the final formula than via any other known
processing route without detrimental effects to some key
properties of the matrix (caking, compression, etc.).
THE AGGLOMERATION STEP
The term "agglomeration," as used herein, means mixing
and/or granulation of the above mixture in a fine dispersion
mixer at a blade tip speed of from about 5m/sec. to about 50
m/sec., unless otherwise specified. The total residence time
of the mixing and granulation process is preferably in the
order of from O.l to l0 minutes, more preferably 0.l-5 and
most preferably 0.2-4 minutes. The more preferred mixing and
WO93/18123 ~3~172 PCT/US93/01790
13
granulation tip speeds are about 10-45 m/sec. and about 15-40
m/sec.
Any apparatus, plants or units suitable for the
processing of surfactants can be used for carrying out the
process according to the invention. Suitable apparatus
includes, for example, falling film sulphonating reactors,
digestion tanks, esterification reactors, etc. For mixing/
agglomeration any of a number of mixers/agglomerators can be
used. In one preferred embodiment, the process of the
invention is continuously carried out. Especially preferred
are mixers of the FukaeR FS-G series manufactured by Fukae
Powtech Kogyo Co., Japan; this apparatus is essentially in
the form of a bowl-shaped vessel accessible via a top port,
provided near its base with a stirrer having a substantially
vertical axis, and a cutter positioned on a side wall. The
stirrer and cutter may be operated independently of one
another and at separately variable speeds. The vessel can be
fitted with a cooling jacket or, if necessary, a cryogenic
unit.
Other similar mixers found to be suitable for use in the
process of the invention include DiosnaR V series ex Dierks &
Sohne, Germany: and the Pharma MatrixR ex T K Fielder Ltd.,
England. Other mixers believed to be suitable for use in the
process of the invention are the FujiR VG-C series ex Fuji
Sangyo Co., Japan; and the RotoR ex Zanchetta & Co srl,
Italy.
Other preferred suitable equipment can include EirichR,
series RV, manufactured by Gustau Eirich Hardheim, Germany;
LodigeR, series FM for batch mixing, series Baud KM for
continuous mixing/agglomeration, manufactured by Lodige
Maschinenbau GmbH, Paderborn Germany; DraisR Tl60 series,
manufactured by Drais Werke GmbH, Mannheim Germany; and
WinkworthR RT 25 series, manufactured by Winkworth Machinery
Ltd., Bershire, England.
WO93/18123 X1~ 72 PCT/US93/01790
14
The Littleford Mixer, Model #FM-130-D-12, with internal
chopping blades and the Cuisinart Food Processor, Model #DCX-
Plus, with 7.75 inch (l9.7 cm) blades are two examples of
suitable mixers. Any other mixer with fine dispersion mixing
and granulation capability and having a residence time in the
order of 0.l to l0 minutes can be used. The "turbine-type"
impeller mixer, having several blades on an axis of rotation,
is preferred. The invention can be practiced as a batch or a
continuous process.
OPERATING TEMPERATURES
Preferred operating temperatures should also be as low
as possible since this leads to a higher surfactant
concentration in the finished particle. Preferably the
temperature during the agglomeration is less than l00-C, more
preferably between l0 and 90 C, and most preferably between
20 and 80 C. Lower operating temperatures useful in the
process of the present invention may be achieved by a variety
of methods known in the art such as nitrogen cooling, cool
water jacketing of the equipment, addition of solid CO2, and
the like; with a preferred method being solid CO2, and the
most preferred method being nitrogen cooling.
FINAL AGGLOMERATE COMPOSITION
The present invention produces agglomerates of high
density for use in detergent compositions. A preferred
composition of the final agglomerate for incorporation into
granular detergents has a high surfactant concentration. By
increasing the concentration of surfactant, the
particles/agglomerates made by the present invention are more
suitable for a variety of different formulations. These high
surfactants containing particle agglomerates require fewer
finishing techniques to reach the final agglomerates, thus
freeing up large amounts of processing aids (inorganic
powders, etc.) that can be used in other processing steps of
the overall detergent manufacturing process (spray drying,
dusting off, etc).
~093/18123 2~ PCT/US93/01790
The agglomerates made according to the present invention
are large, low dust and free flowing, and preferably have a
bulk density of from about 0.4 to about l.2 g/cc, more
preferably from about 0.6 to about 0.8 g/cc. The weight
average particle size of the particles of this invention are
from about 200 to about l000 microns. The preferred granules
so formed have a particle size range of from 200 to 2000
microns. The more preferred granulation temperatures range
from about 10~C to about 60 C, and most preferably from about
20~C to about 50~C.
DRYING
The desired moisture content of the free flowing agglomerates
of this invention can be adjusted to levels adequate for the
intended application by drying in conventional powder drying
equipment such as fluid bed dryers. If a hot air fluid bed
dryer is used, care must be exercised to avoid degradation of
heat sensitive components of the granules. It is also
advantageous to have a cooling step prior to large scale
storage. This step can also be done in a conventional fluid
bed operated with cool air. The drying/cooling of the
agglomerates can also be done in any other equipment suitable
for powder drying such as rotary dryers, etc.
For detergent applications, the final moisture of the
agglomerates needs to be maintained below levels at which the
agglomerates can be stored and transported in bulk. The
exact moisture level depends on the composition of the
agglomerate but is typically achieved at levels of 1-8% free
water (i.e. water not associated to any crystalline species
in the agglomerate) and most typically at 2-4%.
GRANULAR DETERGENT COMPOSITIONS CONTAINING THE AGGLOMERATES
The present invention also encompasses free flowing
granular detergent compositions containing the agglomerates
described hereinabove and processes to make them ;
W093/18123 213~172 PCT/US93/01790
16
Said detergent compositions may comprise additional
detergency builders and powders which may be added to the
agglomerates to give a free flowing granular detergent
composition. The additional detergency builder and powders
may be combined into an aqeous slurry and spray dried to form
a powder, and/or simply added to the agglomerates in a dry
powder form.
In a preferred embodiment of the invention at least part
of the builder is incorporated into a surfactant free slurry
which has physical properties which make it suitable for
spray drying by conventional process. A free flowing granular
detergent composition is then made by mixing these spray
dried particles, with the agglomerates of the invention and
with any other detergency builders and powders.
DETERGENCY BUILDERS AND POWDERS
Any compatible detergency builder or combination of
builders or powder can be used in the process and
compositions of the present invention.
The detergent compositions herein can contain
crystalline aluminosilicate ion exchange material of the
formula
NaZ[(Al02)Z (SiO2)y] xH20
wherein z and y are at least about 6, the molar ratio of z to
y is from about l.0 to about 0.4 and z is from about l0 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 l, said
material having a magnesium ion exchange capacity of at least
about 50 milligram equivalents of CaC03 hardness per gram of
anhydrous aluminosilicate. Hydrated sodium Zeolite A with a
particle size of from about l to l0 microns is preferred.
~093/18123 Z~3~172 : PCT/US93/01790
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/gallon/minute/gram/gallon, based on calcium ion
hardness. Optimum aluminosilicate for builder purposes
exhibit a calcium ion exchange rate of at least about 4
grains/gallon/minute/gram/gallon.
The amorphous aluminosilicate ion exchange materials
usually have a Mg++ exchange of at least about 50 mg eq.
CaCO3/g (12 mg Mg++/g~ and a Mg++ exchange rate of at least
about 1 grain/gallon/minute/gram/gallon. Amorphous materials
do not exhibit an observable diffraction pattern when
examined by Cu radiation (1.54 Angstrom Units).
CA 02131172 1997-12-02
18
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[(Alo2)12(sio2)12] xH2o
wherein x is from about 20 to about 30, especially about 27
and has a particle size generally less than about 5 microns.
The granular detergents of the present invention can
contain neutral or alkaline salts which have a pH in solution
of seven or greater, and can be either organic or inorganic in
nature. The builder salt assists in providing the desired
density and bulk to the detergent granules herein. While some
of the salts are inert, many of them also function as
detergency builder materials in the laundering solution.
Examples of neutral water-soluble salts include the
alkali metal, ammonium or substituted ammonium chlorides,
fluorides and sulfates. The alkali metal, and especially
sodium, salts of the above are preferred. Sodium sulfate is
typically used in detergent granules and is a particularly
preferred salt. Citric acid and, in general, any other
organic or inorganic acid may be incorporated into the
granular detergents of the present invention as long as it is
chemically compatible with the rest of the agglomerate
composition.
Other useful water-soluble salts include the compounds
commonly known as detergent builder materials. Builders are
WO93/18123 2 ~ 3 1 1 7 ~ PCT/US93/01790
.
19
generally selected from the various water-soluble, alkali
metal, ammonium or substituted ammonium phosphates,
polyphosphates, phosphonates, polyphosphonates, carbonates,
silicates, borates, and polyhyroxysulfonates. Preferred are
the alkali metal, especially sodium, salts of the above.
Specific examples of inorganic phosphate builders are
sodium and potassium tripolyphosphate, pyrophosphate,
polymeric metaphosphate having a degree of polymerization of
from about 6 to 21, and orthophosphate. Examples of
polyphosphonate builders are the sodium and potassium salts
of ethylene diphosphonic acid, the sodium and potassium salts
of ethane l-hydroxy-1,1-diphosphonic acid and the sodium and
potassium salts of ethane, 1,1,2-triphosphonic acid. Other
phosphorus builder compounds are disclosed in U.S. Pat. Nos.
3,159,581; 3,213,030; 3,422,021; 3,422,137; 3,400,176 and
3,400,148.
Examples of nonphosphorus, inorganic builders are sodium
and potassium carbonate, bicarbonate, sesquicarbonate,
tetraborate decahydrate, and silicate having a molar ratio of
sio2 to alkali metal oxide of from about 0.5 to about 4.0,
preferably from about 1.0 to about 2.4. The compositions
made by the process of the present invention does not require
excess carbonate for processing, and preferably does not
contain over 2% finely divided calcium carbonate as disclosed
in U.S. Pat. No. 4,196,093, Clarke et al., issued Apr.1,
1980, and is preferably free of the latter.
As mentioned above powders normally used in detergents
such as zeolite, carbonate, silica, silicate, citrate,
phosphate, perborate, etc. and process aids such as starch,
can be used in preferred embodiments of the present
invention.
Brief descriPtion of the drawinas
~'
WO93/18123 PCT/US93/01790
Z~3'1172
Fig. l shows graphs of shear stress and viscosity
plotted against shear rate. The paste tested is 77% by weight
sodium Cll-Cl3 linear alkyl benzene sulphonate solution,
measured at 70~C.
Fig. 2 shows graphs of shear stress and viscosity
plotted against shear rate. The paste tested is 76% by weight
sodium Cl4-Cl5 alkyl sulphate solution, measured at 70 C.
Fig. 3 shows graphs of shear stress plotted against rate
for five different paste compositions. The percentaqe by
weight of sodium Cl4-Cl5 alkyl sulphate solution : sodium
Cl3-Cl5 alkyl ethoxy sulphate (with average of 3 ethoxylates)
is a) 70:0, b)68:2, c)66.5:3.5, d)63:7, e) 56:14.
In each case the aqueous paste is measured at 70 C.
Fig. 4 shows graphs of shear stress and viscosity
plotted against shear rate. The paste tested is 78% by weight
of a mixture of sodium Cll-Cl3 linear alkyl benzene
sulphonate and sodium tallow alkyl sulphate. The two
surfactants being present in equal proportions. The aqueous
paste is measured at 70 C.
Fig. 5 shows graphs of shear stress and viscosity
plotted against shear rate. The paste tested is 74.8% by
weight of a mixture of sodium Cll-Cl3 linear alkyl sulphonate
and sodium tallow alkyl sulphate. The two surfactants being
present in equal proportions. The paste also includes 3.2% by
weight of sodium Cl3-15 alkyl ethoxy sulphate (with an
average of 3 ethoxylates). The aqueous paste is measured at
70 C.
EXAMPLES
l. In each of the following examples, the anionic surfactant
paste was made by sulphation of a fatty alcohol followed
by neutralisation by 48-50% aqueous solution of sodium
WO 93/18123 Z13'Z ~72 PCI/US93/01790
21
hydroxide in a continuous neutralisation loop at
production rates between l and 2 tonnes/hour.
A 76% active paste of Cl4-Cl5 sodium alkyl sulphate has a
rheological profile as shown in Figure 2. There is a
distinct shear thickening region at shear rates of
between about 20 and 40 s~l.
The following examples a-e illustrate how the rheological
profile is modified by the addition of Cl3-Cl5 sodium
alkyl ethoxy sulphate (with an average of 3 ethoxylate
groups) In examples b-e the aIkyl ethoxy sulphate is
injected into the neutralisation loop.
a b c d e
Alkyl sulphate 70 68 66.5 63 56
Alkyl ethoxy 0 2 3.5 7 14
sulphate
water(and 30 30 30 30 30
misc.)*
The shear thickening behaviour of compositions a-c can be
seen in Figure 3. By contrast, examples d and e do not
show shear thickening behaviour, but rather they behave
as shear thinning liquids (with a yield point).
2. In the following example a mixture of Cll-Cl3 linear
alkyl benzene sulphonate and tallow alkyl sulphate (equal
parts of each by weight) was made by coneutralisation
with a 48-50% aqueous solution of sodium hydroxide at a
production rate of 1-2 tonnes/hour.
~ PCT/US93/01790
WO93/18123
2~31~72 22
F (Fig. 4) G (Fig. 5)
Cll-C13 LAS 39 37.l
TAS 39 37.4
Alkyl ethoxy 0 3.2
sulphate
water (and 22 22
misc.)*
The compositions in example F (see Fig. 4) behaves
erratically in the neutralisation loop because of large
pressure fluctuations caused by the rheological
characteristics of this composition. This makes steady
state production of this paste composition impossible by
continuous neutralisation loop.
The composition in example G (see Fig. 5) contains 3.2%
by weight of Cl3-Cl5 alkyl ethoxy sulphate (average of 3
ethoxylates) which makes the resulting paste composition
behave as a shear thinning liquid.
Note : In examples l and 2 the total percentage reported for
water also includes a low level of impurities, mainly
unsulph(on)ated materials e.g. alcohols, fatty acids.
