Note: Descriptions are shown in the official language in which they were submitted.
`` 1163522
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CONTROLLED-SUDSING DETERGENT COMPOSITIONS
This invention relates to controlled suds washing
. powders containing alkyl benzene sulphonate as a detergent
; ~ I active component primarily designed for use in front
. ~ loading or drum type washing machines.
Most controlled suds washing powders contain anionic
surfactants usually in admixture with nonionic
surfactants, and the suds generated by the surfactants is
~: controlled by a suds suppressant, soap being the one most
: commonly used~ However, manufacturers are beginning
to be willing to accept the cost penalty of using suds
~ controllers other than soap because of the increased
: flexibil~ity they give in formulation of thç detergent
active component. Even so, it is necessary to minimise the
additional cost which use of these compounds involves.
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We have now discovered that when an alkyl benzene
sulphonate is used as the anionic surfact component of the
washing powder, and an alkyl phosphoric acid or a salt
thereof is used as the suds controller, then very effective
suds control can be achieved by a selection of the type of
alkyl benzene sulphonate used.
Accordingly the present invention provides a washing
powder comprising 5% or more by weight of water-soluble
salts of alkyl benzene sulphonates in which the total
content of alkyl groups containlng 14 or more carbon atoms
is less than 15% by weight of the alkyl material, and a
suds controller comprising an alkyl phosphoric acid or a
salt thereof.
The alkyl benzene precursors of the sulphonates of the
invention may be prepared from cracked wax olefines, from
polymerized lower olefines or by any other desired route,
provided that they conform to the chain length and
molecular weight criteria of the invention.
The characteristics of the alkyl benzene sulphonates
are extremely important to the present invention, since we
have discovered that if sulphonates containing high
proportions of alkyl groups having 14 or more carbon atoms
are used, the suds produced requires significantly greater
amounts of suds controller to be used in order to achieve
the target suds profile.
It is preferred that the total content of alkyl
sulphonates having 14 or more carbon atoms is less than 5%
by weight. Also preferred is that the mean molecular
weight of the unsulphonated hydrocarbon is from 235 to 245.
The alkyl benzene sulphonates may be used in
combination with other anionic detergent active species.
Examples of such materials are sodium primary and secondary
alkyl sulphates, sodium olefine sulphonates and sodium
alkane sulphonates. Of these, the C12-C20 primary and
secondary alkyl sulphates are preferred.
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Preferred total amounts of anionic surfactant in the
compositions of the invention are from 5 to 25~ by weight,
most preferably 5 to 15~ by weight. Desirably the selected
alkyl benzene sulphonates will constitute at least half of
these amounts and in any event at least 5~ by weight of the
composition.
Nonionic surfactants may also be present in the
compositions of the invention in amounts of up to 15% by
weight. Preferred nonionic surfactants are the C8-C24
primary and secondary aliphatic alcohols, ethoxylated with
from 3 to 25 moles of ethylene oxide per mole of alcohol.
Particularly preferred are the C10-C18 primary alcohol
ethoxylates containing from 5 to 15 moles of ethylene
oxide. We have found C12 15 primary alcohol 7EO
ethoxylate to be best from the point of view of detergency.
The second essential component of the compositions of
the invention is an alkyl phosphoric acid, or a salt
; thereof, preferably mixed with a hydrocarbon oil or wax.
The preferred alkyl phosphoric acids have the general
formula
.~ O
~I
RlO(EO)n - P - OH (I)
~l 25
where A is -OH or R2O(EO)m-, Rl and R2 are the same
or different C12-C24t preferablY C16 C22' straigh
or branched chain, saturated or unsaturated alkyl groups,
essentially C16-C18 linear saturated groups, and
m and n are the same or different and are O or an integer
of from 1 to 6. Preferably A is -OH and n is O, so that
the compounds are monoalkyl phosphoric acids, preferably
with linear alkyl groups. These compounds may be present
either as the free acid or as a sodium, potassium, calcium
or magnesium salt or as a mixture thereof.
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The amount of the alkyl phosphoric acid or salt
thereof used in the detergent compositions can be varied
widely from a minimum level of about 0.05% up to a
practical maximum of about 5, preferably about 0.1% to
about 3% by weight. Higher levels than 5% can be employed
but this would be uneconomical and would generally not give
any product advantages.
Suitable hydrocarbon waxes for use in the detergent
compositions are water insoluble materials of either
synthetic, mineral, vegetable or animal origin, which are
dispersible in the detergent solutionsO The waxes should
normally melt at a temperature between about 20C and about
120C, preferably not more than about 90C and especially
in the range of about 30C to about 70C, i.e. lower than
the maximum intended wash temperatures for the detergent
compositions.
The preferred waxes are of mineral origin, especially
those derived from petroleum, including microcrystalline
and oxidised microcrystalline petroleum waxes, petroleum
jelly ('Vaseline') and paraffin waxes. Petroleum jelly is
correctly a semi-solid wax, usually having a drop melting
point of about 50C, but is for convenience here grouped
with other solid waxes. Synthetic waxes such as
Fischer-Tropsch and oxidised Fischer-Tropsch waxes, or
~lontan waxes, or natural waxes such as beeswax, candelilla
and carnauba waxes may be used if desired. Any of the
waxes described may be used alone or in admixture with
other waxes. The waxes should be readily dispersible in
the detergent liquor but not soluble therein, and
preferably they should not have very high saponification
values, e.g. not in excess of about 100. Emulsifying or
stabilising agents for the waxes can also be included
in the detergent composition.
The amount of wax is normally from about 0.05% to
about 10%, preferably about 0.1% to about 5% and especially
about 0.5% to about 3% in the composition. The total
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amount of the alkyl phosphoric acid or salt and the
hydrocarbon wax is generally from about 0.2% to about 20
by weight of the composition, preferably about 0.5~ to
about 5~ by weight. The ratio of the amount of the alkyl
phosphoric acid or salt to the wax can be varied widely
rom about 1:25 to about 10:1 parts by weight but is
generally from about 1:20 to about 10:1 parts by weight,
preferably from about 1:10 to about 1:1 parts by weight.
- In addition to the wax which may be used with the
alkyl phosphoric acid or salt in the detergent composition,
a hydrocarbon oil may also be present, either added
separately or jointly with the wax, for example in order to
facilitate addition of the wax or to modify its melting
point or dispersion eharacteristics.
Examples of suitable liquid hydrocarbons are mineral,
vegetable or animal oils of which colourless mineral oils
are preferred. Either light or heavy mineral oil or
mixtures thereof may be employed, but of eourse any liquid
. hydrocarbon used must be of low volatility at normal fabric
washing temperatures. Other oils which could be used if
desired are vegetable oils such as sesame oil, cottonseed
oil, corn oil, sweet almond oil, olive oil, wheat germ oil,
rice bran oil, or peanut oil, or animal oils such as
lanolin, neat's foot oil, bone oil, sperm oil or eod liver
oil. Any such oils used should of course not be highly
eoloured, of strong odour or otherwise unaeceptable for use
in a detergent eomposition.
Other suds eontrollers may also be used in eombination
with the alkyl phosphoric acid-based suds controllers.
Examples of these are silieone~based eontrollers, for
example partieles of granular sodium tripolyphosphate
impregnated with organopolysiloxane and encapsulated in
wax, or hydrophobic silica particles impregnated with an
organopolysiloxane. Another example, which is of
particular interest, is a particle having a spherieal or
eylindrical core, desirably of sucrose, coated with an
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absorbent such as titanium dioxide which is impregnated
with polysiloxane, the whole particle being coated with
wax. Mixtures of polysiloxanes and waxes or ethylene
distearimides either alone or in admixture with waxes can
also be used as auxiliary suds controllers.
A detergency builder will normally be included within
the compositions of the invention. Several suitable
; detergency builders are well-known and commercially
available, examples being alkali metal, ortho-, pyro- and
tripolyphosphates, alkali metal carbonates and
- bicarbonates, alkali metal polyphosphonates, alkali metal
nitrilotriacetates and the host of organic builders which
have been suggested as a response to the anti-phosphate
lobby, examples of which are sodium carboxymethyloxy-
succinate, sodium citrate, and sodium polyacrylate.
Other detergency builders are the sodium carbonate/
finely divided calcite combination, and the crystalline or
amorphous aluminosilicate cation exchange materials. These
builders may be used in an amount of from 5 to 80% by
weight of the composition, preferably 10 to 60% by weight.
The compositions of the invention may also contain
oxygen bleaches such as sodium perborate and sodium
percarbonate, fillers such as sodium sulphate, and moisture
and minor components such as slurry hydrotropes, corrosion
inhibitors, anti-redeposition agents, anti-ashing agents,
anti-oxidants, fluorescers and optical brighteners,
enzymes, blue-whiteners and pigments and dyestuffs.
The invention will be further illustrated by the
following Examples.
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Example l
A series of spray-dried powders was produced to the
following general formulation and by the following general
method:
Parts by Weight
Sodium alkylbenzene sulphonate 8.0
: . p
rimary Cl2_l5 alcohol
ethoxylate 7EO 3.0
Sodium silicate 8.0
Sodium tripolyphosphate 35.0
Sodium sulphate 7.0
Sodium carboxymethylcellulose l.0
Moisture, fluorescers and stabilisers 14.0
.
A suds suppressant in the form of a mixture of one
part of Cl6 alkyl phosphoric acid ester with three parts
of petroleum jelly was sprayed onto this powder as it fell
in a cascade from one conveyor belt to another. 24 parts
of sodium perborate tetrahydrate were then mixed with the
spray-dried powder, together with perfume.
The suds produced by each powder, varying one from the
other as shown below, were assessed as follows:
2'- kg loads of white terry cotton towelling were
washed in Hoover (registered trade mark) front-loading
automatic washing machines using water of 26H hardness and
200 g of powder. The washing programme used washes at
90C .
The suds height of each wash liquor was measured using
an arbitrary scale attached to the window of the machines.
Each suds assessment was performed four times, the average
suds height being quoted in the following tables, which are
interpolations from a graph. The graph was produced
directly from the results in the experiments.
In the first series of experiments, three sets of
powder were used, Set A, the control set, containing a
sulphonate of an alkyl benzene having a molecular weight of
35 ~
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~55 and Sets B and C, the sets in accordance with the
invention, containing a sulphonate of an alkyl benzene
having a molecular weight of 241 and 242 respectively.
The actual alkyl chain length distribution is shown in
Table 1.
Five variants of each set of powder were prepared by
-` spraying the powder with 0.6, 0.8, 1.0, 1.2 and 1.4% by
weight respectively of the alkyl phosphoric acid/petroleum
jelly mixture and the suds height was assessed as
described. The results are shown in Table 2.
It can be seen that whereas Powder A containing an
alkyl benzene sulphonate having substantial proportions of
C14, C15 and C16 alkyl groups in the composition
produces over-foaming at the lower levels of suds-
suppressant, the powders in accordance with the inventiondo not, and indeed produce only a trace of suds at the
higher levels of suppressant.
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