Note: Descriptions are shown in the official language in which they were submitted.
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C.3118
DETERGENT COMPOSITIONS
This invention relates to detergent compositions, in
particular built detergent compositions with low or zero
levels of phosphate. Detergent composltions
conventionally include, in addition to a detergent active
material, a phosphate detergency builder, such as sodium
tripolyphosphate. However, in view of the environmental
problems which may occur in some cases with the discharge
of phosphates into waste waters, it is desirable to reduce
the level of phosphorous in detergent compositions.
It has been proposed to use both alkali metal
carbonates and aluminosilicate material as alternatives to
phosphate builder materials. Belgium Patent 861 435
(Colgate) discloses a phosphate-free particulate detergent
composition comprising both an alkali metal carbonate and
bicarbonate, zeolite and a nonionic detergent.
We have now discovered that improved detergency can
be achieved with a detergent composition which can be
substantially free of phosphate builders, and which
includes an alkali metal carbonate and an aluminosilicate
material, by the addition of a seed crystal. Thus,
acrording to the invention there is provided a detergent
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composition comprising from about 5 to about ~0~ by weight
of at least one synthetic detergent active material, from
about 18 to about 40~ by weight of a water-insoluble
aluminosilicate based on the anhydrous material, from 5~ to
50% by weight of an alkali metal carbonate and from 1~ to
10~ by weight of a calcium carbonate seed crystal having a
surface area of at least 2m2/g.
The detergent composition according to the invention
necessarily includes a synthetic detergent active material
otherwise referred to herein simply as a detergent
compound. The detergent compound may be selected from
anionic, nonionic, zwitterionic and amphoteric synthetic
detergent active materials and mixtures thereof. Many
suitable detergent compounds are commercially available
and are fully described in the literature, for example in
"Surface Active Agents and Detergents", Volumes I and II,
by Schwartz, Perry and Berch.
A preferred level of the detergent compound in the
composition from 10% to 25~ by weight.
The preferred detergent compounds which can be used
are synthetic anionic and nonionic compounds. The former
are usually water-soluble alkali metal salts of organic
sulphates and sulphonates having alkyl radicals containing
from about 8 to about 22 carbon atoms, the term alkyl
being used to include the alkyl portion of higher acyl
radicals. Examples of suitable synthetic anionic
detergent compounds are sodium and potassium alkyl
sulphates, especially those obtained by sulphating
higher (C8-C18) alcohols produced for example from tallow
or coconut oil, sodium and potassium alkyl tCg-C20)
benzene sulphonates, particularly sodium linear
secondary alkyl (C10-Cl5) benzene sulphonates; sodium
alkyl glyceryl ether sulphates, especially those ethers
of the higher alcohols derived from tallow or coconutF'' '7 oil and synthetic alcohols derived from petroleum;
sodium coconut oil fatty monoglyceride sulphates
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and sulphonates; sodium and potassium salts of sulphuric
acid esters of higher (C8-Cl8) fatty alcohol-alkylene
oxide, particularly ethylene oxide, reaction products; the
reaction products of fatty acids such as coconut fatty
acids esterified with isethionic acid and neutralised with
sodium hydroxide; sodium and potassium salts of fatty acid
amides of methyl taurine; alkane monosulphonates such as
those derived by reacting alpha-olefins (C8-C20) with
sodium bisulphite and those derived from reacting paraffins
with SO2 and Cl2 and then hydrolysing with a base to
produce a random sulphonate; and olefin sulphonates, which
term is used to describe the material made by reacting
olefins, particularly Cl0-C20 alpha-olefins, with SO3 and
then neutralising and hydrolysing the reaction product.
The preferred anionic detergent compounds are sodium
(C11-C15) alkyl benzene sulphonates and sodium ~C16-C18)
alkyl sulphates.
Suitable nonionic detergent compounds which may be
used include, in particular, the reaction products of
compounds having a hydrophobic group and a reactive
hydrogen atom, for example aliphatic alcohols, acids,
amides or alkyl phenols with alkylene oxides, especially
ethylene oxide either alone or with propylene oxide.
Specific nonionic detergent compounds are alkyl (C6-C22)
phenols-ethylene oxide condensates, generally up to 25 EO,
ie up to 25 units of ethylene oxide per molecule, the
condensation products of aliphatic (C8-C18) primary or
secondary linear or branched alcohols with ethylene oxide,
generally up to 40 EO, and products made by condensation of
ethylene oxide with the reaction products of propylene
oxide and ethylenediamine. Other so-called nonionic
detergent compounds include long chain tertiary amine
oxides, long chain tertiary phosphine oxides and dialkyl
sulphoxides.
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Mixtures of detergent compounds, for example mixed
anionic or mixed anionic and nonionic compounds may be used
in the detergent compositions, particularly in the latter
case to provide controlled low sudsing properties. This
is beneficial for compositions intended for use in
suds-intolerant automatic washing machines.
Amounts of amphoteric or zwitterionic detergent
compounds can also be used in the compositions of the
invention but this is not normally desired due to their
relatively high cost. If any amphoteric or zwitterionic
detergent compounds are used it is generally in small
amounts in compositions based on the much more commonly
used synthetic anionic and/or nonionic detergent compounds.
For example, mixtures of amine oxides and ethoxylated
nonionic detergent compounds can be used.
Soaps may also be present in the detergent
compositions of the invention. The soaps are particularly
useful at low levels in binary and ternary mixtures,
together with nonionic or mixed synthetic anionic and
nonionic detergent compounds, which have low sudsing
properties. The soaps which are used are the
water-soluble salts of C10-C20 fatty acids in particular
with inorganic cations such as sodium and potassium. It is
particularly preferred that the soaps should be based
mainly on the longer chain fatty acids within this range,
that is with at least half of the soaps having a carbon
chain length of 16 or over. This is most conveniently
accomplished by using soaps from natural sources such as
tallow, palm oil or rapeseed oil, which can be hardened if
desired, with lesser amounts of other shorter chain soaps,
prepared from nut oils such as coconut oil or palm kernel
oil. The amount of such soaps can be up to about 20% by
weight, with lower amounts of 0.5~ to about 5% being
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generally sufficient for lather control. Amounts of soap
between about 2% and about 20%, especially between about 5%
and about 15%, can advantageously be used to give a
beneficial effect on detergency and reduced levels of
incrustation.
The alkali metal carbonate and water insoluble
aluminosilicate are used as detergency builder materials in
the present invention. The alkali metal carbonate is
preferably selected from carbonates and sesquicarbonates of
sodium and potassium and is most preferably sodium
carbonate.
The alkali metal carbonate is preferably present in
the detergent composition at a level of about 5% to about
50% by weight, most preferably from about 10% to about 40%
by weight of the composition.
The aluminosilicate material is preferably
crystalline or amorphous material having the general
formula:
Naz (AlO2)z (SiO2)y x H2O
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 0.5, and x is an
integer from 15 to 264 such that the moisture content is
from 10% to 28% by weight. The alumino-silicate
preferably has a particle size of from 0.1 to 100 microns,
ideally between 0.1 and 10 microns and a calcium ion
exchange capacity of at least 200 mg.calcium carbonate/g.
In a preferred embodiment, the water-insoluble
aluminosilicate ion exchange material has the formula
Nal2(Al02siO2)l2xH2o
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wherein x is an integer of from 20 to 30, preferably about
27. This material is available commercially as Zeolite A.
The aluminosilicate material is preferably present in
the detergent composition at a level within the range from
about 1% to about 40%, based on the anhydrous material, by
weight of the composition.
- In addition to the essential alkali metal carbonate
and aluminosilicate material it is possible to include
minor amounts of other precipitating builder materials,
other ion-exchange builder materials and sequestering
builder materials. Preferably the further builder
material is a non-phosphate material.
Preferably the calcium carbonate seed crystal is any
crystalline form of calcium carbonate, such as calcite,
aragonite or travertine or a mixture thereof. Most
preferably the seed crystal is calcite. The calcium
carbonate seed crystal preferably has a surface area of at
least 2m2/g, most preferably at least 30m2/g. A level
from about 1% to about 10% by weight of the seed crystal in
the detergent composition is preferred. Below a level of
1% the addition of calcite has no effect on the detergency
of the detergent composition. No further improvement in
detergency is found if more than 10% by weight of calcite
is added to the detergent composition.
Apart from the essential detergent active compounds,
alkali metal carbonate, aluminosilicate builder and
crystallisation seed, a detergent composition according to
the invention may contain any of the conventional additives
in the amounts in which such materials are normally
employed in fabric washing detergent compositions.
Examples of these additives include lather boosters such as
alkanolamides, particularly the monoethanolamides derived
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from palm kernel fatty acids and coconut fatty acids,
lather depressants, antiredeposition agents, such as sodium
carboxymethyl cellulose and cellulose ethers,
oxygen-releasing bleaching agents such as sodium perborate
and sodium percarbonate, peracid bleach precursors,
chlorine-releasing bleaching agents, fabric softening
agents, inorganic salts, such as sodium sulphate, and
usually present in very minor amounts fluorescent agents,
perfumes, germicides and colourants.
It is also desirable to include in the compositions an
amount of an alkali metal silicate, particularly sodium
ortho-, meta- or preferably neutral or alkaline silicate.
The presence of such alkali metal silicates at levels of at
least about 1~, and preferably from about 3% to about 15%,
by weight of the composition, is advantageous in decreasing
the corrosion of metal parts in washing machines, besides
giving processing benefits and generally improved powder
properties. The more highly alkaline ortho- and meta-
silicates would normally only be used at lower amountswithin this range, in admixture with the neutral or
alkaline silicates.
It is generally also desirable to include a
structurant material, such as succinic acid, and/or other
dicarboxylic acids, sucrose and polymers, in detergent
compositions of the invention, to provide a powder having
excellent physical properties. When the detergent
compositions contain succinic acid this can react with the
alkali metal carbonate present to give an alkali-metal
bicarbonate, or sesquicarbonate.
Detergent compositions according to the invention may
be produced by any of the techniques commonly employed in
the manufacture of fabric washing detergent compositions,
including particularly slurry-making and spray-drying
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processes. The calcium carbonate seed crystal and the
following optional components, the silicate material,
enzyme, bleach and perfume, may be post-dosed to a
spray-dried powder comprising the detergent active, the
detergency builders and any other optional materials.
The invention is further illustrated by the following
non-limiting examples.
Example 1
The water softening capacity of a number of
co-builders when added to zeolite A (Wessalith, P, ex
Degussa) was examined. Two grams of zeolite were added to
a litre of 40FH water. (The water hardness was adjusted
using stock solutions of calcium chloride). After one
minute, lg (occasionally 2g) of a co-builder was added.
Experiments were carried out at ambient temperature and at
40C. Values of pCa for each solution were determined
using conventional methods.
Co-builder pCa ~after 20 minutes)
ambient 40C
Na2CO3 (~0.lg calcite*) 5.19 6.01
Na2C3 _ 5 59
zeolite 5.60 5.60
No co-builder (control) 4.20 4.42
.~
`'~ * calcite (Omyalite 90, ex Omya).
These results demonstrate that the addition of calcite
to a solution comprising zeolite and carbonate has a
positive effect on the softness of the water when compared
with the control.
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Example 2
The influence of the amount, and type, of calcite on
the water softening performance of a detergent composition
was investigated in this example.
- ~ Varying amounts of two forms of calcite, Omyalite 90
~~ and Socal U3 (ex Solvay), which have surface areas of
10.8m2/g and 80m2/g respectively, were added to a solution
of a detergent composition in 40FH water, at a temperature
of 22C. The detergent composition comprised 20% zeolite
A, 20% sodium carbonate, 9% alkyl benz~ne sulphonate (DOBS
JN) and 4% of an alkoxylated alcohol (Synperonic A7) and
was present at a level of 5g/1.
After 15 minutes a value of pCa-for each detergent
composition was measured. Figure 1 shows graphically the
variation of pCa with the concentration of calcite, where
the level of calcite is based on the weight of sodium
carbonate present in the composition.
Clearly, at a level of calcite of greater than 15%,
based on the weight of sodium carbonate, the replacement of
low surface area calcite by high surface area calcite gives
a significant improvement in the water softening capacity
of the detergent composition.
Example 3
Calcite (Socal U3), sodium perborate monohydrate and
alkaline sodium silicate were post-dosed to a spray-dried
powder detergent composition comprising 8.1% alkyl benzene
sulphonate ~irene X12L, ex SIR), 3.6% of an alkoxylated
alcohol (~utensol AO-7, ex BASF), 3.7% soap, 27.7% sodium
carbonate, 18% zeolite A, 6.5% sodium sulphate, 2% succinic
acid, and minor quantities of other conventional detergent
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additives. The sodium perborate monohydrate and alkaline
sodium silicate were present at levels of 9~ and 5%
respectively in the detergent composition. For comparison
purposes a composition was prepared in which the calcite
was replaced by an equivalent amount of sodium sulphate.
The compositions were added to water of varying hardness
and pCa values were measured. The following results were
obtained.
Dosage Water No ~ 4%
hardness Socal U3 Socal U3
pCa
5g/1 40FH 3.85 5.28
(all Ca)
5g/1 27FH 4.25 5.25
(Ca:Mg of 4:1)
2g/1 10FH 4.40 5.26
(all Ca)
5g/1 27FH 3.74 4.10
(all Ca)
Clearly the presence of calcite in the composition has
a positive effect on the softness of the water.
Example 4
Six different test cloths were washed in a laboratory
apparatus with a detergent composition (X) comprising 9%
alkyl benzene sulphonate (DOBS~JN), 4% of an alkoxylated
alcohol (Synperonic~A7), 20% zeolite A, 20~ sodium
carbonate, 2% calcite (Socal U3), 10% sodium sulphate, 5%
alkaline sodium silicate and 0.5% sodium carboxylmethyl
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cellulose. For comparison purposes test cloths were also
washed in the same detergent composition except that it
contained no calcite (Detergent composition Y). These
experiments were carried out in 40FH water at a
temperature of 40C with a concentration of the detergent
composition of either 4 or 8g/1; the duration of the wash
cycle was 20 minutes. The test cloths were then dried and
the value of ~R at 460 nm was determined using a "Zeiss
Elrepho" reflectometer fitted with a UV filter (~R
represents the difference in the value of the reflectance
of the test cloth compared to the untreated cloth).
Triplicate experiments were performed and the following
results were obtained.
Test cloths were washed at 40C with the detergent
composition present at a level of 4g/1.
" R460
Detergent X Y
composition
Test Cloths
a 13.1 9.2
b 15.8 15.2
c 12.2 11.1
d 17.5 9.4
e 16.8 13.3
f 9.8 5.4
Test cloths were washed at 40C with the detergent
composition present at a level of 8g/1.
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~ R460
Detergent X Y
composition
Test Cloths
a 17.7 14.6
b 24.7 21.0
c 16.6 15.6
d 21.7 20.5
e 25.3 22.4
f 21.6 14.9
These results demonstrate the significant effect
including calcite in a detergent composition, comprising
carbonate and zeolite as co-builders, has on reflectance
values.
Example 5
Calcite, sodium perborate monohydrate and alkaline
sodium silicate were as post-dosed to a spray-dried powder
detergent composition comprising 8.1% alkyl benzene
sulphonate (Sirene X12L, ex SI~), 3.6% of an alkoxylated
alcohol (Lutensol AO-7, ex BASF), 3.7% soap, 27.7% sodium
carbonate, 18~ zeolite A, 6.5~ sodium sulphate, 2% succinic
acid, and minor quantities of other conventional detergent
additives. The sodium perborate monhydrate and alkaline
sodium silicate were present at levels of 9% and 5
respectively in the detergent composition.
A range of different calcite materials (defined in
terms of surface area m2/g) were tested. The following
table gives the levels of calcite used.
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Example Surface Area % Calcite ~ 460
Calcite (m /q)
5A 0 23.9
5B 0.75 10 28.4
5C 10.8 10 28.7
5D 23 10 30.4
5E 80 3 31.8
5F 80 6 31.3
5G 80 10 31.8
5H 80 20 28.5
Test cloths were washed in a laboratory apparatus with
each of the above detergent compositions. The experiments
were carried out in 40FH water at a temperature of 60C
with a concentration of the detergent composition of 5gtl,
the duration of the wash cycle was 20 minutes. The test
cloths were then dried and the value of ~ R at 460nm was
determined using a "Zeiss Elrepho" reflectometer fitted
with a UV filter. (~R is defined as in Example 4).
The results clearly demonstrate that replacement of
low surface area calcite by high surface area calcite gives
a detergent composition with improved detergency. The
results further show that increasing the level of calcite
above 10% by weight gives no further improvement in
detergency.
As used herein, "FH" with respect to water hardness
is the molar concentration of free hard water ions x 10 4.
As used herein, "pCa" is the negative logarithm of the
free calcium ion concentration.
All percentage weights are based on the anhydrous
material.
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The words "Zeiss Elrepho" used herein is a registered
Trade Mark.
