Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
5;~
This invention relates to detergen-t compositions
containing a silicone foam contro]ling agent.
The use of solid detergent compositions in the
laundering of soiled ~abrics is now well-known and ~idely
practised. Compositions of this type can however give rise
to excessive foaming during the wash cycle, particularly when
employed in automatic washing machines. Such excessive foaming
is ob~ectionable in that it interferes with the efficient
laundering of the fabrics and causes overflowing and flooding
~- 10 of the machine.
One method of overcoming this problem is proposed in
U.K. Patent No. 1,378,874 which relates to a foam control
substance comprising powdered or granular sodium tripoly-
phosphate having on its surface an organopolysiloxane anti-
foam. Such foam control substances can be incorporated into
powdered or granular detergent compositions and are effective
in reducing or suppressing the foaming of aqueous wash liquors
in which the detergent is employed. It has, however, been
~- found that such foam control substances lose some of their
effectiveness when incorporated into certain detergent com-
positions, especially those with a high anionic surfactant
content, which are subsequently stored for prolonged periods.
We have now found that the loss of effectiveness of
foam control substances of the type described can be reduced
if the silicone antifoam is at least partially enclosed within
a mixture of ~ water-insoluble wax and a water-insoluble
emulsifying agent. Accordingly the present invention provides
a powdered or granular detergent composition containing from
0.5 to 20~ by weight of a foam control substance which
.
, ,
3~ 3Z
comprises powclered or granular sodium tripol~phosphate,
sodium sulphate or sodium perborate having on the surface
thereof an organopolysiloxane antifoam agent which is ak
least partially enclosed within a mixture of a water-insoluble
wax having a melting point in the range from above 55C to
~-~ below 100C and a water-insoluble emulsifying agent.
` Thus, in accordance with the present teachings, a
powdered or granular detergent composition is provided which
contains from 0.5 to 20% of a foam control substance con~
sisting essentially of (A) a powdered or granular compound
selected from sodium tripolyphosphate, sodium sulphate and
sodium perborate having on the surface thereof (B) an organo-
polysiloxane antifoam agent which is at least partially
enclosed within a mixture of (C~ a water-insoluble wax which
. has a melting point within the range from above 55C to
below 100C and (D) a water insoluble emulsifying agent,
there is up to 120 parts (B) per 100 parts (A), a weight
ratio of (C) + (D) to (B) of from 1.5/1 to 10/1 and a weight
ratio of (C) to (D) of from 0.5/1 to 5/1. : Any organopolysiloxane antifoam agent which is
.` effective in controlling foaming in aqueous media may be
employed to prepare the foam control substance used in the
compositions of this invention. A variety of such antifoam
-~ agents are known and are described for example in U.K. Patent
.. Specifications Nos. 689,306 r 859,329, 1,020,022, 1,n51,687,
1,051,688, 1,079,832 and 1,110,207. They are normally either
viscous paste-like materials or aqueous emulslons. Generally
the antifoam agent comprises a polydlorganosiloxane in ad-
mixture w~th from 1 to 10 per cent of its weight of a finely-
divi`.ded filler ~avi~ng a high ~at least S0 s~uare metres
per gram) surface area to weight rat~o, e.g. a fume or
--3--
f~
~1
. , " ;,, ., ' . '~ ',,, :
'~ , ' '' "'~ : ' ~
3LS3Z
precipitated silica or fume aluminium oxide. The poly-
diorganosiloxane component usually has a viscosity at
25C in the range from 50 to 5000 cS. However, poly-
diorganosiloxanes having viscosity outside this range can
be used.
The si]icon-bonded substituents in the organopoly-
siloxane are usually methyl radicals. The organopolysiloxane
may, however, also contain other organic radicals, for
example, alkyl, alkenyl, aryl, aralkyl and alkaryl radicals
such as ethyl, propyl, octyl, tetradecyl, phenyl, benzyl
and 2-phenylpropyl, or aminoalkyl radicals as described in
U.K. Patent Specification No. 1,050,996. When radicals
other than methyl
.,.
~'~
, ~ -3a-
la~.s3~
~- are present they preferably comprise less than about 50 per
cent of the total silicon-bonded radicals in the organopoly-
siloxane.
The polydiorganosiloxanes employed in the antifoam
may or may not be end-stopped. Thus they may be terminated
for example with hydroxyl radicals or end-stopped with tri-
organosiloxy radicals e.g. trimethylsiloxy, phenyldimethyl-
siloxy or dimethylvinylsiloxy radicals.
Preferred for use in this invention are antifoams
based on or containing polydimethylsiloxanes and a high (at
least 50 m2/g.) surface area silica. Among the preferred
antifoam compositions are those comprising a mixture of from
80 to 98 per cent by weight of polydimethylsiloxane and from
- 2 to 20 per cent by weight of a silica having a surface area
- of at least 50 m2/g. Also included in the group of preferred -
antifoams are those comprising a silica, a polydimethylsiloxane
and a polydiorganosiloxane which contains silicon-bonded
methyl, ethyl and 2-phenylpropyl radicals, the silica being
present in a proportion of from 1 to 10 per cent by weight
- 20 based on the total weight of polydiorganosiloxane.
In addition to the organopolysiloxane component the
:
silicone antifoam may contain other ingredients, for example,
resin copolymers of (CH3)3SiOo 5 and SiO2 units as described
in U.K. Patent Specification No. 1,110,207.
:
As the water-insoluble wax there may be employed for
example, polyethylene wax, Montan wax, oxidised microcrystal-
line wax, carnauba wax, ceresin wax and ozokerite. The wax
should have a melting point of above 55C but below 100C.
` As the water-insoluble emulsifying agent there may be
employed, for example, the esters of fatty acids and polyhydric
_ ~ _
.
~i3Z
alcohols, e.g. sorbi-tan monooleate, sorbitan monostearate,
ethylene glycol monostearate, glycerol monostearate and
polyoxyethylene distearate, and the reaction products of
alcohols or phenols, particularly the fatty alcohols, with
ethylene oxide, e.g. polyoxyethylene nonylphenyl ether,
polyoxyethylene oleyl ether, polyoxyethylene lauryl ether
and tallow alcohol ethoxylates, said ethers or ethoxylates
containing low proportions of ethoxy groups, usually from
about 2 to 5 such groups, per molecule. In general, non-
ionic emulsifiers with an HLB value below 8 are preferred.
In the foam control substances present in thecompositions of this invention the organopolysiloxane
` antifoam agent is at least partially enclosed in a mixture
of the water-insoluble wax and the water-insoluble emulsify-
ing agent. Such an arrangement may be arrived at by mixing
the organopolysiloxane antifoam agent and the sodium tri-
polyphosphate, sodium sulphate or sodium perborate so that
the antifoam agent becomes dispersed over the surface of the
solid. The treated solid is then contacted with the mixture
of water-insoluble wax and emulsifying agent whereby it
- becomes at least partially encapsulated by said mixture. Any
suitable technique may be employed for treating the solid
substrate with the organopolysiloxane antifoam agent. For
- example the antifoam agent, in the form of a thick paste,
may be mixed with the substrate using e.g. a ribbon blender
-` to yield a substantially dry and flowable granulate.
Alternatively the antifoam agent may be employed in the form
of an aqueous emulsion to treat the dehydrated or partially
dehydrated substrate. For example dehydrated sodium tripoly-
phospha~e may ~e contacted with sufflcient antifoam emulsion
-- 5 --
.
-to supply up to six molecules of H2O per molecule of
sodium tripolyphosphate.
An alternative method of preparing the foam control
substance comprises mixing the organopolysiloxane antifoam
agent with the wax and emulsifying agent and applying the
mixture to the surface of the solid substrate, e.g. the
sodium tripolyphosphate. Such application may be carried
out by simple mixing of the solid substrate with the other
components at an elevated temperature so that the wax and
emulsifying agent are molten. The resulting mixture may
then be allowed to cool and thereafter crushed. The substrate
can also be coated with the molten mixture of organopolysiloxane,
wax and emulsifier by containing the powder in a fluidized
bed and spray drying the melt onto the fluidized powder mass.
The proportion of organopolysiloxane antifoam agent
present in the foam control substance is not narrowly critical
and will depend on several factors, including the defoaming
effect desired in the detergent composition and the method
employed to prepare the foam control substance. Depending
on the particular substrate up to about 120 parts of antifoam
agent per 100 parts of substrate can be applied to provide a
free flowing powder which is then subsequently coated with
the mixture of wax and emulsifying agent. When the organo-
polysiloxane antifoam agent is mixed with the wax and
.. i
emulsifying agent prior to application to the substrate the
proportion of antifoam agent in relation to the other components
of the foam control substance can also be varied within wide
limits. In general it is preferred that the total amount of
. . .
wax and emulsifying agent be at least equal to the amount
.. . . ,, ~
'.i32
of organopolysiloxane antifoam agent. Preferably the ratio
of the total weight of wax and emulsifying agent to the
weight of organopolysiloxane antifoam agent is from 1.5/1
to 10/1. The proportion of wax to emulsifying agent can be
varied within Eairly wide limits but preferably falls within
the range from 0.5/1 to 5/1.
The hereinabove described foam control substances are
incorporated into powdered or granular detergent compositions
in a proportion of from 0.5 to 20~ by weight, based on total
composition weight, to provide the compositions of -this
invention. Powdered or granular detergent compositions are
well-known and typically contain by weight from 10 to 25 per
cent of an organic surface active agent, and about 15 to 50
per cent of an inorganic phosphate e.g. sodium tripolyphosphate.
:: .
Other ingredients which are normally present include one or more
of sodium sulphate, sodium silicate, sodium perborate, foam
builders, optical brighteners and perfumes. Typical of the
organic surface active agents which are present are sodium salts
of alkylaryl su~phonates, sulphates of straight chain primary
alcohols, sodium alkyl glyceryl ether sulphonates and sodium
and potassium salts of fatty acid mixtures. Specific examples
of such organic surface active agents are sodium dodecyl
benzene sulphonate, sodium lauryl sulphate and potassium stearate.
The invention is illustrated by the following examples,
in which the parts are expressed by weight.
Example 1
.
Two compositions were prepared. Composition A was
obtained by mixing for 3 hours at 175C a silica (3 parts)
having a viscosity at 25C of about 1500 cS, a methyl to
. :.
~ - 7 -
::~
,
3~ :
silicon ratio of 1:1, an ethyl to silicon ratio of ahout
0.8:1 and a 2-phenylpropyl to sil:icon ratio of about 0.2:1.
Composition s was obtained by mixing a trimethylsiloxy-
terminated polydimethylsiloxane (88 parts) having a viscosity
at 25C of 1000 cS, a silica aerogel (10 parts) and a resin
copolymer of (CH3)3SiOo 5 and SiO units (2 parts) in which
the ratio of the former to the latter units was in the range
from 0.6:1 to 102:1.
An organopolysiloxane antifoam agent was prepared by
~ 10 mixing together 50 parts of each of Composition A and Com-
position B. The paste-like product (10 parts) was then mixed
with Brij 72 (a stearyl alcohol ethoxylate) (12 parts) and
oxidised Montan wax (11.4 parts) at about 80 C. This mixture
was tumble mixed while molten with granular sodium tripoly-
phosphate (66.6 parts) and the mix allowed to cool to yield
` a granular foam control substance which was free-flowing at
room temperature.
10.5 parts of the foam control substance prepared as
described above were thoroughly mixed into 98 parts of a heavy
duty, granular detergent sold under the trade designation Omo.
The mi~ was stored in a cardboard container under laboratory
conditions of temperature and humidity for 4 weeks. In order
to evaluate the sudsing properties of the detergent composition
portions (108.5 g.) of the composition were taken prior to,
during and at the end of the four week storage period. Each
portion was evaluated by addition to 28 litres of cold water,
hardness 50 ppm Ca++, in a Philips Autostar automatic washing
machine calibrated with a O - 17 cm. foam height scale. The
; maximum foam height achieved during the washing cycle was noted,
- 8 -
, ' .
.. . . . . .
-
. .
- ~
~V~ 3Z
the wash load consisting of 2 kg. of clean cotton. The
results obtained are shown in the following table.
- .,
Storage Period O 1 week 3 weeks 4 weeks
._ .. _. _
Maximum Foam Height 13 ~ 10 1o
Example 2
~ The procedure described in Example 1 was repeated
- except that the foam control substance was prepared from
6.7 parts of the mixture of Compositions A and B, 15 parts
of Brij 72, 11.6 parts of oxidized Montan wax and 66.6 parts
of sodium tripolyphosphate. This foam control substance was
employed in a proportion of 15.75 parts per 98 parts of Omo.
The foam heights obtained initially and after storage
for 2 and 4 weeks were 9, 10 and 15 cm. respectively.
;:
_ g _
. . , ~ , .
.
