Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to ~ process ~or the
production of a detergent powder and to -the powders the~-
selves.
Spray-dried deterge~t powder~ co~taining a
nonionic surfaotant a9 the major detergent-active
compone~t ~that is more tha~ 50% by weight of the to-tal
detergent active material) have recently been i~troduced
~o the ~arket i~ Britain. ~hese powders have a very
good washing performance but they are not easy to manu~acture.
One of the difficulties which arises during -the prepara-tio~
of the spray-dried portion o~ the powcler ~herea~ter referred
to as the base powder) i9 that it can au-to-oxidise under
normal spray-drying tower temperature conditions. ~his is
not a feature of conve~tional alkyl be~ze~e sulpho~ate-based
powders.
We have now discovered that the autoxidation
temperature or the time to autoxidation at a given -temperature
of detergent base powders o~ high nonionic content can be
increased substantially by incorporting a relatively high
level of c~n alkanola~ide into the slurry a~d by enJuri~g
that the slurry re~ains 3u~ficiently alkali~e.
Accordingly, the present i~ventio~ provides a proce~s
for the production o~ a detergent base powder oontaining a
nonionic sur~actant as the ma~or deterge~t-active ingredien-t
which comprises spray drying a slurry comprising part or all
of the,nonionic surfactant, an alkaline material in an amount
equivalent to,at least 5% of sodium oxide, c~nd from ~ to 6%
of an,alkanolamide,~the~ercentages being expressed as
proportions o~the base powder.; ; ~,l
~ The invention also provides a base powder produced
by the process.
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9~32
The problem o~ autoxidation varies i~ degree ~rom
one specific no~ionic sur~actant to another. Whilst we
consider that the measures suggested in this speci~ication
will be efiective with all ~onionic sur~actants i~ reducing
the autoxidatio~ temperature~ or the time to autoxidation
at a give~ temperature, clearly when using those nonionic
sur~actants ior which autoxidation i9 not a severe problem,
the benefit obtai~ed ~ro~ t~e inventio~ will be reduoed.
We have ~ound that the inventio~ is particularly adva~tageous
when the ~ollowing no~ionic suriactants are used:-
1. Nonylphenol 8,10,12 and 15 (moles) ethyleneo~ide condensates
2. ~ergitol 1~-S-70 9,12 and 15
3. Tergitol 45-S-7, 9,10,12 and 15
4. Dobanol 25-7,9,12 and 15
~ 5. Dobanol 45-7,9,1~ and 15
~ra~ ~1ark)
-~ 6. Acropol~35-7,991~ and 15
7. Al~ol 12/14 and 14/12-7,9,12 and 15
8. Synperonic 7,9,11 and 15
~ergitols (llrade Mark) are a Unlon Carbide ~erie~
of Cll_l5 and C14_15 9econdary alcohol ethoxylates.
Dobanols ~rade Mar~) are a Shell ~eries o~ pri~ry
C12 1~ alcohol ethoxylates containing about 20~d branched
material.
Acropols are a serie~ of Cl3_15 Oxo alcohol
ethoxylates manu~ac-tured by Ugine-Kuhlman. The alcohols
are 70% C13 and 30~o C15 contai~ing 25% of d methyl branched
material and 10~ o~ ethyl branched material. ~he same
materials are also sold under the Ukanil Trade Mark.
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Alfols 12~14 and 1~112 (Trade Mark) are a series
of Condea Ziegler primary C12_1~ and Cl~ l2 alcohol
ethoxylates.
Synperonics (Trade Mark) are an ICI series of
- 5 C13 15 alcohol ethoxylates, co~-taining 670/o C15 and 33% C
alcohols~ 45-~5~o of which are alkyl blranched, ~09tly
methyl branched alcohols.
The designation.7,9,10,12 and 15 refersto the number
o~ moles o~ ethylene oxide per mole of alcohol.
The term "nonionic sur~actant" as used i~ this
specification i9 intended to re~er in general to lo~g chain
ethoxylates of alcohols and phenols and simllar compounds.
It does not include alkanolamides~ which in some cases have
been included within the general nonionic surfactant ¢lass.
This invention is relevant to the preparation o~
spray dried base powders containing ~rom about 10 to about
r.
20% by weight o~ nonionic surfactant preierably about 13
to about 18~ by weight. A~ter adding the normal proportio~
of dry-dosed ingredients, -this will produce a ~inished
detergent powder having a nonionic sur~actan-t content o~ from
about 7 to 14~ by weight.
All Or this nonionic surPactant material may be i
in.corporated in the slurry to be spray dried~via the crutcher
or some or all o~ it may be injected directly into a slurry
of the other ingredients immediately prior to spray-drying.
The type o~ al~anolamide uséd as in the compositions
o~ the invention. is not believed to be critical. ~hus
mono- an.d di- alkanolamides can be used, as ca~ alkanola~ides
derived ~rom ~atty acids o~ dif~erent chain leng-ths and
those derived~~rom alkanolamines containing various di~erent
alkyl groups as well as those containing polyoxyethyllene/
polyoxypropylene chains. Suitable alkanolamides include
4~
lauric monoethanolamide, lauric diethanolamide, palm kernel
monoethanolamide (PKEA), coconut monoethanolamide (CEA),
caprylic monoethanolamide, caprylic diethanolamide, capric
diethanolamide, tallow monoethanolamide and lauric mono-
isopropanolamide and mixtures thereof.
The process of the invention requires the presence,
in the crutcher slurry, of an alkaline material in an amount
equivalent to at least 5% of sodium oxide. In considering
whether a slurry meets this requirement, the contribution
to the alkalinity of a phosphate builder salt should be ignored.
Thus when the slurry contains sodium tripolyphosphate, sodium
pyrophosphate or sodium orthophosphate, although these salts
have an alkaline reaction, their contribution is not to be
taken into account when determining the sodium oxide equivalen-t
of the alkaline material.
Preferred alkaline materials are sodium silicate
having an SiO2:Na2O ratio of from 1.6:1 to 2:1, sodium
carbonate and sodium hydroxide.
The aqueous slurry to be spray dried may contain
materials other than those already mentioned. For example it
may contain small amounts, for example up to about 5% based on
the weight of the base powder of an anionic surfactant such as
an alkyl sulphate, an alkyl benzene sulphonate or a soap.
Mixtures of tallow and coconut soaps are preferred. An
example of a suitable mixture is from 8 to 9 parts of tallow
soap and from 2 to 1 part of coconut oil soap.
The aqueous slurry will also usually contain a builder
salt, preferably a phosphate builder salt such as sodium
tripolyphosphate, in an amount sufficient to constitute from
about 25 to about 60~, preferably about 40 to about 60% of
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the base powder.
The aqueous slurry will also contain minor ingredients
in conventional amounts. These will include anti-redeposition
agents, fillers, fluorescers, chelating agents and anti-
oxidants. It will also contain water.
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In the ~ollowing examples and tables the e~fect of
alkanolamides and o~ alkaline materials in stabilising
ds-tergent powders having a nonionic surfactant as the ma~or
detergent-active ingredient i9 shown.
The method by which the time taken for a powder to
autoxidise at a given temperature is measured i9 a
modification o~ the method o~ PC Bowes ~nd A Cameron
described in J Appl~Chem. and Biotechnol, 1971. This method
involves suspending cubic open-topped baske-ts co~taining
the powder in a~ oven set to a given temperature. The
powder has a thermocouple embedded in it, connec-ted to a
chart recorder. When autoxidation sets i~ a rapid rise i~
temperature occurs. Unless o-therwise indicated, the present
experi~ents are conducted using a cube o~ 10 cm side and an
oven temperature o~ 150C.
Example 1
Slurries having formulae as detailed below were
made up and spray-dried.
~0 by wo~ight o~ base powder
Component of Slurry A B C D ~ F
Nonionic suriactant 16.116.1 16.1 16.1 16.116.1
Anionic suriactant 6.03.0 6.0 6.0 3.06.0
Coconut ethanolamide (CE~) 2.3 2.3 2.3 - - 2.3
Sodium tripolyphosphate42.342.3'`42.3~ 42.3 54.347.5
Sodium carbonate - - - - - 1,5
Sodium silicate 15.015.0 7.5 15.0 7.57.5
(2.0 : 1?
Sodium hydroxide - - 5.0
Moisture and minorto 100.0 100.0 lOOoO 100~0 100~0 100~0
ingredients
Autoxidation time ~hrs) ~ 48~48 >48 8 2 8
~4" basket, 150 C)
Na20 equivalen~t ~ 5 ~5 ~5 ~ 5 2.53.1
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44982
Powders formed from slurries A, B and-C which
are in accordance with the invention demonstrate acceptably
long times to autoxidation, whereas those formed from
slurries D, E and F which are included for comp~rative
purposes and which are low in alkanolamide or alkaline
material, do not.
Base powders A, B and C may be converted into
finished detergent powders by the usua:l post-dosing
techniques. For example the following dose may be added:
Dosed component % by weight of
Finished Powder
Speckles 7.~
Post-dosed ethanolamide 2.2
Sodium perborate 2~.5
Perfume 0.2
An additional factor which we have found can reduce
the autoxidation temperature or the time to autoxidation at
a given temperature is the introduction into the slurry of
certain reducing agents, particularly sGdium sulphite or
sodium thiosulphate or a mixture thereof. Both of th~se
reducing agents are particularly advantageous since they are
oxidised to sodium sulphate which is present in many detergent
formulations as a filler. Thus introduction of such a
reducing agent into the slurry does not result in the finished
detergent powder containing undesirable material. Amounts of
reducing agents of from about 1 to about 7% have been found
to have some effect in inhibiting autoxidation.
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Example 2
Component of Slurry % by weight o~ base powder
G H
. _ _ _ _
Nonionic surfactant 16.2 16~2 16.2
Coconut soap 300 3.0 3.0
Coconut ethanolamide 2.3 2.3 203
Sodium tripolyphosphate 54.8 54.8 54~8
Sodium silica$e (2.0 : 1)7.6 7.6 7.6
- Sodium sulphite 2.3 - -
Sodium thiosulphate - 6.6
Moisture and minor ingredients to 100 to 100 to 100
Autoxidation time (hr~) > 48 > 48 8
(10 cm basket, lS0 C)
We have discovered that a further measure which can
be taken to prevent or substantially reduce autoxidation is
to ensure that the bulk density of the spray-dried powder
is as high as possible. Whilst the precise bulk density
which can be achieved will vary from composition to
composition, we have found that bulk densities above about
0.35 gm/ml have a substantial effect in reducing autoxidation.
