Note: Descriptions are shown in the official language in which they were submitted.
cC 799
~064361
The invention relates to detergent compositions which
are adapted for fabric washing, and in particular to such
compositions containing phosphate detergency builders.
The most commonly used detergency builders are the
condensed phosphates, especially sodium tripolyphosphate, but
it has been suggested that the use of these phosphate detergency
builders can contribute to eutrophication problems. There have
been very many suggestions for alternative, mainly organic,
materials to be used as detergency builders instead of the
condensed phosphates, but most of these materials tend to be
unsatisfactory for one reason or another, for example they
are less efficient or biologically unacceptable, or they may
simply be too expensive.
It has also been proposed to mitigate the problems of
~ 15 eutrophication by using decreased levels of condensed phosphate
; detergency builders, with or without the presence of other
; detergency builders, but few of these proposals have been
acceptable. Thus, when reduced levels of sodium tripoly-
phosphate are used without supplemental builders, there can
be considerable problems when using the compositions in hard
water if there is insufficient phosphate to sequester all the
calcium ions present, as this causes the precipitation of
insoluble calcium phosphate salts which can accumulate on the
washed fabrics. When a condensed phosphate builder is used
with other types of detergency builders, then they tend to
interact and often the former prevents the latter from
functioning effectively, especially in the case of other
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cC 799
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detergency builders which act by precipitating the calcium
salt, for example sodium carbonate.
We have now found that certain mixtures of synthetic
organic anionic surfactant, sodium tripolyphosphate and
water-soluble soap provide detergency equivalent to
compositions containing high amounts of phosphate. According
to the present invention there is provided a heavy duty
fabric washing powder comprising a surfactant system
consisting essentially of a synthetic organic anionic
surfactant and a water-soluble soap, and a detergency builder
system comprising soap and a tripolyphosphate salt wherein
(a) the synthetic organic anionic surfactant
- is present in an amount of from 5 to 5~/0
by weight
(b) the water-saluble soap is present in an
amount of from 10-3~/~ by weight, and
~c) the tripolyphosphate salt is present in
an amount of between 10 and 2~/~ by weight,
- the balance being conventional fabric washing powder
..
, 20 ingredients. By the suitable choice of the amounts of the
- sodium tripolyphosphate and soap it is possible to formulate
effective detergent compositions containing lower phosphorus
levels than in comparable conventional detergent compositions.
Insofar as these two materials function normally in different
way, ie sodium tripolyphosphate acting as a sequestrant
detergency builder and the soap functioning as a precipitant
builder, it is somewhat surprising that a mixture of the
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cC 799
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materials functions so effectively. In particular, the
tendency for sodium tripolyphosphate to cause inorganic
deposition on washed fabrics when it is used at low levels
in detergent compositions is decreased in the presence of
the soap. Moreover, the sodium tripolyphosphate does not
appear to inhibit the detergency building action of the
soaps, as it does with many other detergency builders, and
any soap not precipitated as the calcium salt, eg when the
compositions are used in soft water or at higher product
concentrations, can function as detergent active compounds,
so increasing the detergency of the compositions.
Instead of the sodium tripolyphosphate there may be
used the potassium salt, but this is more expensive and for
convenience the use of the sodium salt is described and
illustrated in the specification.
The soaps used are the sodium, or less desirably
potassium, salts of C8-C22 fatty acids, especially natural
fatty acids derived from nut oils, such as coconut oil or
palm kernel oil, or tallow class fats, such as beef and
mutton tallows, palm oil, lard, some vegetable b~tters and
castor oil. It is essential to use some soaps of tallow class
soaps, which are soaps of predominantly C14-C20 (mainly C18)
fatty acids, of which normally at least about 40yo are
saturated fatty acids.- The tallow class fats may ~e
; 25 hardened if desired, so as to decrease the content of
unsaturated acids such as oleic acid and linoleic acid, and
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cC 799
~064361
this is particularly beneficial if some more highly poly-
unsaturated oils such as soybean oil are desired to be used
as tallow class fats at significant levels.
It is preferred to use mixtures of soaps derived from
tallow class fats and soaps from nut oils, which are soaps
y C10 C14 (mainly C12) fatty acids, of which
normally at least about 75% are saturated fatty acids; again
the nut oils may be hardened if desired. Such mixtures tend
to have better solubilities than tallow soap alone, coupled
with sufficiently low calcium soap solubilities for
satisfactory detergency building, and sufficiently low
critical micelle concentrations approaching that of tallow
soap alone, to enable any excess of the soap to function as ~,
an extra detergent active component. The preferred mixtures
' 15 are from about 9:1 to 3:1 parts by weight of tallow class
, soap to nut oil class soap~ In general, higher proportions
` o~ tallow class soaps in such mixtur~s give better detergency `
building properties, whilst higher proportions of nut oil
- class soaps give better solubility properties. If desired,
tallow class soap car, be used alone.
In addition to the tallow class soap, and any optional
nut oil soap, some soap of longer carbon chain length can be
used if desired, especi,ally C20-C24 soaps, eg rapeseed soaps,
which are useful for lather-depressing properties, or soaps
of synthetic fatty acids. In contrast to naturally-occurring
^ or derived fatty acids which have linear carbon chain lengths
of even numbers, synthetic fatty acids can have both odd and
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cC 799
1064361
even numbers and they can be of both linear and branched-
chain form. Synthetic fatty acids o carbon chain length
predominantly C14-C20, which are pre~erably at least about
4~/0 saturated and at least about 75% linear, can be used
in partial or full replacement of natural tallow class soaps,
and synthetic fatty acids of carbon chain length predominantly
C10-Cl6, preferably at least about 75% saturated and at least
about 5~/o linear, can be used in partial or full replacement
of natural nut oil soaps. If any branched-chain fatty acids
are used they are preferably ~ -alkyl, eg cC-methyl branched,
rather than being more highly branched.
There have in the past been many suggestions for using
sodium tripolyphosphate as a detergency builder in detergent
compositions comprising soap as a detergent active material.
For example in so-called ternary active mixtures for use in
low sudsing compositions, it is usual to have present some
soap, at a low level of up to about 8% by weight. Normally
such soaps are tallow soaps or soaps of longer-chain length
fatty acids. Also, detergent compositions based on ssap
have contained low amounts of sodium tripolyphosphate.
However, to the Applicants' knowledge, it has not been
proposed hitherto to use the specific detergency builder
mixtures of sodium tripolyphosphate and soap in the proportions
as set out below for use in fabric washing powders according
to the present invention.
The ratio of the soap to the sodium tripolyphosphate in
the detergent composition is preferably less than 1:1,
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cC 799
1064361
generally from about 0. 75 :1 to about 0.9:1 parts by weight.
The total amount of sodium tripolyphosphate plus soap is
preferably about 25% to about 5~/o~ and especially about 30%
to about 50/0, by weight of the composition. Lower levels of
sodium tripolyphosphate are intended for use either at higher
product concentrations or in soft water.
It will be appreciated that the amount of sodium tripoly-
phosphate is chosen according to the overall phosphate
detergency builder level which is desired in the detergent
compositions or according to the maximum permitted phosphoru~
content. An amount of sodium tripolyphosphate is normally
used within the range between about 15 and 2~/o by weight of
the composition, for example about 16%-by weight. However,
lf the compositions of the invention are intended to be used
with decreased phosphate levels for environmental reasons,
- then lower amounts are used. A level of less than 20yo sodium
;; tripolyphosphate by weight of composition is equivalent to less
than about 5% by weight of phosphorus, and it is a feature
of the invention that detergent compositions can be prepared
with these low phosphate levels and yet have good detergent
properties.
The minimum level of soap which should be present is
-` lOyo by weight of the composition, and the maximum level is 30%
; by weight, preferably less than about 25% by weight of the
composition, and especially about 15% to about 2~/o by weight.
The amounts of the sodium tripolyphosphate and soap for
use in a particular detergent composition are selected according
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cC 799
1064361
to the expected washing conditions. We have found for example
that amounts of about 16% and 14% respectively give good
performance (at 4% phosphorus level) for compositions intended
for use at relatively high product concentrations, ie about
0.3% to about 0.8% by weight, as is common practice in Europe,
especially in front-loading automatic washing machines. But
in compositions intended for use at relatively low product
concentrations, ie about 0.1% to 0.3%, as is common practice
~- under North American washing conditions, especially in top-
- 10 loading automatic washing machines, we have found that amounts
of about 16% sodium tripolyphosphate and about 3~/o soap are
required.
The detergent compositions of the invention necessarily
include an amount of a synthetic organic anionic surfactant.
Many suitable detergent active compounds of this type 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.
The preferred compounds are 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,
~! 25 especially those obtained by sulphating the higher (C8-C18)
alcohols produced by reducing the glycerides of tallow or
coconut oil and especially the C16 18 primary alkyl sulphate;
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cC 799
1064361
sodium and potassium alkyl (Cg-C2~) 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
coconut oil and synthetic alcohols derived from petroleum;
sodium coconut oil fatty acid mono~lyceride sulphates and
sulphonates; sodium and potassium salts of sulphuric acid
esters of higher (Cg-C18) fatty alcohol-alkylene cxide,
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 by reacting paraffins with S02 and C12 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 alpha-olefins, with
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S03 and then neutralising and hydrolysing the reaction product.
If desired small amounts of nonionic surfactants may
be used additionally, for facilitating soap scum dispersion
and inhibiting its deposition on washing machine parts.
However it is preferred that nonionic surfactants are entirely
absent. Examples of suitable nonionic surfactants include the
reaction products of alkylene oxides, usually ethylene oxide,
with alkyl (C6-C22) phenols, generally 5 to 25 E0; ie 5 to 25
units of ethylene oxide per molecule; the condensation products
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cC 799
1064361
of aliphatic (C8-C18) primary or secondary alcohols with
ethylene oxide, generally 6 to 30 EO, and products made by
condensation of ethylene oxide with the reaction products of
propylene oxide and ethylenediamine. Other so-called nonionic
detergent active compounds include long chain tertiary amine
oxides, long chain tertiary phosphine oxides and dialkyl
sulphoxides, which are propertly semi-polar compounds.
Amounts of amphoteric or zwitterionic detergent active
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 active
compounds are used it is generally in small amounts. However,
some such zwitterionic or amphoteric compounds, especially
sulphobetaines such as hexadecyldimethylammoniopropane sulphonate,
have useful soap scum dispersion properties.
The amount of the synthetic organic detergent active
compound or compounds used is generally in the range of from
about 5% to 50~o, preferably about 7% to about 15%, by weight
of the compositions, depending on the desired properties. Some
of the soap added can also act as a detergent active compound
in so-called "overbuilt" circumstances, ie at higher product
concentrations or when using soft water. The ratio of the
total detergent compounds to the total of the amount of sodium
tripolyphosphate and soap should generally be in the range of
from about 10 1 to 1:10, especially about 3:1 to 1:5, parts
; by weight.
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cC 799
106436~
Apart from the detergent active compounds and detergency
builders, a detergent composition of the invention can contain
any of the conventional additives in the amounts in which such
additives are normally employed in fabric washing detergent
powders. Examples of these additives include lather boosters
such as alkanolamides, particularly the monoethanolamides
derived from palm kernel fatty acids and coconut fatty acids,
powder flow aids such as silicas and aluminosilicates, lather
depressants, anti-redeposition agents, such as sodium carboxy-
methylcellulose, oxygen-releasing bleaching agents such as
sodium perborate and sodium percarbonate, per-acid bleach
precursors, chlorine-releasing bleachin~ agents such as tri-
chloroisocyanuric acid and alkali metal salts of dichloroiso-
cyanuric acid, fabric softening agents such as clays of the
smectite and illite types, anti-ashing aids, starches, soap
scum dispersants, inorganic salts such as sodium sulphate,
and usually present in very minor amounts, fluorescent agents,
perfumes, enzymes such as proteases and amylases, germicides
and colourants. In addition, it may be desirable to add
slurry stabilisers such as copolyethylene-maleic anhydride
.,
and copolyvinylmethylether-maleic anhydride, usually in salt
form.
It is also possible to include in the detergent compositions
` of the invention minor amounts, eg not more than about 25% by
~! 25 weight, of other detergency builders, which may be either
' so-called precipitant builders or sequestrant builders. This
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cC 799
1064361
detergency whilst using particularly low levels of the sodium
tripolyphosphate, so as to achieve particularly low phosphorus
contents in the detergent compositions. Examples of such
other detergency builders are amine carboxylates such as
sodium nitrilotriacetate, and sodium carbonate. It may also
be noted that some minor amounts of sodium pyrophosphate and
sodium orthophosphate are normally formed by hydrolysis of
sodium tripolyphosphate during spray drying processes to make
detergent powders, so low levels of these other phosphate
builders may be present in the detergent compositions.
It is 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 silicate at levels of for example about 5%
to about 15% by weight, is usually advantageous in decreasing
the corrosion of metal parts in washing machines, besides
giving processing benefits and generally improved powder
properties. In additon, the amount of silicate can be used
to some extent to control the pH of the compositions which
should generally be within the range of about 9 to about 11,
preferably about 9.5 to about lO.S, in aqueous solution of
the compositions at the recommended concentrations~ A high
pH, ie over about pH 10.5, tends to be more efficient as
regards detergency but it may be less desirable for domestic
safety.
The fabric washing powder may be produced by any of the
techniques commonly employed in the manufacture of fabric
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cC 799
~064361
washing compositions, including particularly slurry making and
spray drying processes. However, it has been found that the
presence of appreciable levels of soap in the detergent slurries
tends to give rise to problems in spray drying, notably the
production of powders of low bulk density and with high
proportions of small particles (fines).
In a further aspect of the invention, it has been found
beneficial to produce the detergent compositions by a slurry
making and spray drying process in which either none or only a
proportion of the soap, preferably not more than about 8% by
weight, is added to the slurry and all or the remainder of
the soap is post-dosed to the spray dried powder in particulate
form, eg as noodles, granules, pellets, ribbons, threads,
flakes, small spheres or marumes. It may be beneficial in
this case to add minor ingredients, for example perfumes, to
the detergent compositions in the post-dosed soap particles.
Such soap particles can be made by the usual processes
depending on the final shape and size desired, and it is
preferable to mill the soap thoroughly before making the
particles, as this tends to improve their solubility,
especially for particles with a higher content of tallow soap.
Alternatively, it is possible to spray dry two separate
slurries, either in the same or different spray drying towers,
and then mix them to form the final composition. In this case,
one slurry preferably has all the major ingredients in it but
not more than about 8% by weight of soap, and the other slurry
has a mjaor proportion of soap with other minor ingredients.
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cC 799
` 1064361
The term "spray drying" is used above to include processes in
which detergent slurries are sprayed into relatively hot gas,
normally air, either in counter-current or co-current processes
and processes in which hotter slurries are sprayed into
relatively cool air, ie in so-called spray drying or flash
drying processes. Conventional slurry and drying gas
temperatures are used in such spray drying processes for
producing the detergent compositions according to the invention.
The invention is illustrated by the following Examples in
which parts and percentages are by weight except where otherwise
indicated.
- Example 1
A detergent composition was prepared to the following
^ formulation:
Ingredient %
Sodium alkyl benzene sulphonate 7
Nonionic detergent compound 3
Soapl 2 6
Soap noodles 12
Sodium tripolyphosphate 19
Sodium sulphate 9
Sodium silicate 8
Sodium perborate 25
Sodium carboxymethylcellulose
Moisture + minor ingredients
balance to 100
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cC 799
1064361
1 Sodium soap made from tallow fatty acids and hardened
rapeseed fatty acids (1:1 mixture), added in the
detergent slurry~
Sodium soap noodles made from mixed tallow soap and
coconut soap (70:30).
The above composition was made by spray drying an aqueous slurry
of the ingredients except for the soap noodles and the sodium
perborate which were post-dosed to the spray dried powder. The
composition had a higher bulk density and better powder
properties than a powder of like formulation made by spray
drying the whole composition except for the sodium perborate.
m is composition compared favourably for detergency
properties with a commercially available low sudsing formulation
containing 35% of sodium tripolyphosphate instead of the mixed
sodium tripolyphosphate and soap builders, and otherwise similar
ingredients.
Exam~le 2
,
A spray dried detergent composition was prepared to the
following formulation:
Ingredient Parts - % by weight of
flnlshed composi_ion
Sodium alkyl benzene sulphonate 16.0 13.g
Sodium tripolyphosphate 16.0 13.9
Sodium alkaline silicate 6.0 5.2
Sodium carbonate 20.0 17.4
Sodium carboxymeth~lcellulose 0.4 0.3
Water and fluorescent agents 11.6 10.1
70.0
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cC 799
1064361
This composition was then admixed with 45 parts by weight of
a separately spray dried composition having the following
formulation:
Ingredient Parts% by weight of
Sodium soap (tallow:coconut, 29.7 25.8
74:2~)
Coconut fatty ethanolamide1.6 1.4
Sodium alkaline silicate 6.0 5.2
- Sodium ethylenediamine tetra- 0.2 0.2
acetate -
Fluorescent agent 0.4 0.3
Moisture balance to 100
45.0
The resultant composition was found to compare favourably for
detergency properties with comm~rcially available nonionic-
and anionic-based detergent compositions containing 33% of
sodium tripolyphosphate.
Example 3
The procedure of Example 2 was repeated except that instead
of the 45 parts of the soap-based spray dried composition, 30
parts of potassium tallow soap in noodle form were added to the
spray dried base powder. Similar favourable detergency properties
were exhibited.
Example 4
A detergent composition was prepared to the following
formulation:
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cC 799
1064361
Ing~edient %
Alkyl benzene sulphonate 7.0
Tallow alcohol - 18 EO 1.5
Sodium tallow soap 15.0
. Sodium hardened fish oil soap 3.0
Sodium tripolyphosphate 19.0
Sodium alkaline silicate 5.0
Sodium carboxymethylcellulose 1.5
: Fluorescent agents and preservative 0.4
Sodium perborate 30.0
Water (and minor additives) 18.6
,: , 100 . O
: This product was produced by a slurry making and spray drying
process in which all of the ingredien~s except for the
- perborate were added in the slurry, and the perborate was
admixed with the resultant powder.
This detergent powder was found to have good detergency
properties in comparison with a commercially available
detergent powder of higher (30% phosphate) content.
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