Note: Descriptions are shown in the official language in which they were submitted.
1335~88
DETERGENT COMPOSITION
This invention relates to a detergent composition, in
particular to a detergent composition for washing fabrics.
Fabric washing compositions contain, as an essential
ingredient, a surfactant system whose role is to assist in
the removal of soil from the fabric and its suspension in
the wash liquor. Suitable detergent active materials fall
into a number of classes, including anionic, nonionic and
cationic materials and marketed products contain materials
selected from one or more of these classes.
The most widely used anionic detergent active
materials are the alkyl benzene sulphonates and these
provide satisfactory results especially at high
temperatures. There has been a desire to find alternative
~.
~ 2 1335488
anionic surfactants for use in circumstances when alkyl
benzene sulphonates are undesirable, but generally speaking
the performance of other anionic detergent active materials
is unsatisfactory.
Among such alternative anionic surfactants are the
primary alcohol sulphates (PAS) otherwise known as alkyl
sulphates. The PAS derived from tallow fat has been
rec~ ~nded for use. Thus, GB 1399966 (The Procter & Gamble
Company) discloses a detergent composition in which the
surfactant system is a mixture of sodium tallow alkyl
sulphate and a nonionic detergent active material. However,
tallow PAS suffers from the disadvantage that its
performance at low temperatures is poor. With the trend
towards lower wash temperatures this becomes a serious
disadvantage.
Other PAS's have been proposed in the art. Thus, for
example, GB 1399966 referred to above, also discloses the
possibility of using the PAS derived from coconut oil. We
have appreciated that under some circumstances coconut PAS
can perform better than tallow PAS at low temperatures, but
under such circumstances its perfo ~n~e at higher
temperatures is significantly poorer than the tallow derived
material. Thus, while the consumer expects a single product
to perform satisfactorily both at high and low temperatures,
the replacement of tallow PAS by coconut PAS is not an
attractive option.
An objective of the present invention is to provide a
surfactant system based on PAS and which is able to give a
good combination of perfol -nce levels at a range of
temperatures.
We have found that this can be achieved with a PAS
which has a wider spread of alkyl chain lengths than is the
case when either tallow alone or coconut alone is the source
of the alkyl chains. Use of a PAS derived from a mixture of
3 1335488
-
sources can perform better than tallow PAS at low
temperatures and better than coconut PAS at higher
temperatures. Under some circumstances there is better
performance than with either tallow or coconut PAS. Even
though these may give better performance at certain
temperatures, use of PAS with a wider spread of alkyl chain
lengths can give good performance over a wider temperature
range.
The spread of chain lengths may be characterised by
the presence of alkyl ChA; n~ of twelve and eighteen carbon
atoms in amounts or a ratio which does not occur when the
alkyl chains come from a single natural source.
Thus, according to a first aspect of this invention
there is provided a detergent composition for washing
fabrics, the composition contAi ni ng a surfactant system
comprising an anionic surfactant the major ingredient of
which is alkyl sulphate of mixed alkyl chain length such
that at least 10% by weight of the alkyl ch~ i n~ present in
the alkyl sulphate are Cl 2 ChA,in~ at least 20% by weight of
said alkyl chains are C18 chains and the weight ratio of C1 2
alkyl chains to C1 8 alkyl chains is in the range 9:4 to 1:6,
preferably 2:1 to 1:5.
For comparison in a coconut feedstock the percentages
of C1 2 and C1 8 alkyl are typically 53% and 12%, amounting to
a ratio over 3:1 (and indeed over 4:1) while in a tallow
feedstock the alkyl chains can be 70% C1 8 alkyl with C1 2
almost entirely absent.
In compositions of this invention, preferably at least
15% by weight of the alkyl chains present in the alkyl
sulphate are C1 2 while the C1 8 alkyl chAins are at least 25%
by weight of the alkyl ChAi ns in the alkyl sulphate.
As stated, the alkyl sulphate of mixed chain lengths
is over 50% of the anionic surfactant present. Of course it
4 1335488
may constitute the whole of the anionic surfactant present.
Preferred is that the alkyl sulphate is at least 60% or even
at least 80% of the anionic surfactant present.
Alkyl sulphates are also known as sulphated fatty
alcohol salts. The alkyl sulphates, which are particularly
envisaged for this invention, are normally produced from
natural alcohols, such as those produced by reducing the
glycerides of naturally occurring fats and oils.
Natural alcohols rich in C1 2 alkyl ch~in~ include
those derived from babassu, coconut, ouri-coury and palm
kernel while alcohols rich in C1 8 chains include those
derived from beef tallow, kapok, olive, peanut, sesame, tall
oil and teaseed.
Natural alcohols may be hardened, in which case
unsaturated alkyl chains will be absent. However PAS from
unhardened materials, such as unhardened tallow alcohol, may
be employed so that unsaturated ch~ i n~ are present. C1 8
unsaturated chains will normally be oleyl but further
unsaturation may be present e.g. linoleic chains may be
present.
In addition to the C1 2 and C1 8 chains in the PAS
materials useful in the present invention, other alkyl and
unsaturated chains may be present. These chains will
normally have between 8 and 18 carbon atoms. Materials
which contain more than a small amount, i.e. more than about
2%, of chains containing more than 18 carbon atoms or less
than 8 carbon atoms are less preferred.
From the point of view of ready availability, it is
preferred to use a PAS derived from a mixture of tallow and
coconut in the weight ratio of from 3:1 to 1:3, most
preferably from 2:1 to 1:2.
It is preferred to use the water-soluble salts of
1335~88
these anionic surfactants, specifically the alkali metal
(sodium or potassium) salts thereof.
Preferred compositions according to the invention
include from 2% to 50%, such as from 4% to 30% by weight of
the surfactant system.
The compositions of the invention also preferably
contain a nonionic surfactant. We have found it to be of
advantage if such a nonionic surfactant has an HLB of less
than 10.5, although there is benefit even if the nonionic
surfactant has an HLB greater than this.
Suitable nonionic surfactants which may be used are
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, the
condensation products of aliphatic (C8 - C18) primary or
secondary linear or branched alcohols with ethylene oxide,
and products made by condensation of ethylene oxide with the
reaction products of propylene oxide and ethylenediamine.
When alkylene oxide adducts of fatty materials are
used as the nonionic surfactants, the number of alkylene
oxide groups per molecule has a considerable effect upon the
HLB of the nonionic surfactant. The chain length and nature
of the fatty material is also influential, and thus the
preferred number of alkylene oxide groups per molecule
depends upon the nature and chain length of the fatty
material.
We have found it of advantage that the weight ratio
between the anionic surfactant and the nonionic surfactant
lies between 10:1 and 1:4, most preferably between 4:1 and
1:2.
1335488
The surfactant system may include other surfactant
materials in addition to the specified alkyl sulphate and
the above mentioned nonionic materials. These other
surfactant materials may be selected from other anionic
detergent active materials, zwitterionic or amphoteric
detergent active materials or mixtures thereof.
The level of any such further surfactant materials
will not exceed 50% of the composition. It is preferably
not more than 40% of the total amount of surfactant in the
composition, and may perhaps be not over 5~ by weight of the
whole composition.
The other anionic detergent active materials which may
be present may be the usual water-soluble alkali metal salts
of organic sulphonates having alkyl radicals cont~i ni ng 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 (Cg - 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 coconut oil and synthetic alcohols
derived from petroleum; sodium coconut oil fatty
monoglyceride sulphates and sulphonates; sodium and
potassium salts of sulphuric acid esters of higher (C8 to
Cl 8 ) fatty alcohol-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
S02 and Cl2 and then hydrolysing with a base to produce a
random sulphate. A further anionic detergent active which
may be included is soap, especially soap with a high
-
proportion of unsaturated acyl chains. 13 ~ 5 4 8 8
The compositions of the invention may contain a
detergency builder material, this may be any material
capable of reducing the level of free calcium ions in the
wash liquor and will preferably provide the compositions
with other beneficial properties such as the generation of
an alkaline pH and the suspension of soil removed from the
fabric. The amount of builder material in a composition of
this invention may in particular be from 15% to 60% by
weight of the composition.
Examples of phosphorus-contAining inorganic detergency
builders, when present, include the water-soluble salts,
especially alkali metal pyrophosphates, orthophosphates,
metaphosphates, polyphosphates and phosphonates. Specific
examples of inorganic phosphate builders include sodium and
potassium tripolyphosphates, orthophosphates and
hexametaphosphates.
Examples of non-phosphorus-containing inorganic
detergency builders, when present, include water-soluble
alkali metal carbonates, bicarbonates, silicates and
crystalline and amorphous aluminosilicates. Specific
examples include sodium carbonate (with or without calcite
seeds), potassium carbonate (with or without calcite seeds),
sodium and potassium bicarbonates and silicates.
Examples of organic detergency builders, when present,
include the alkali metal, ammonium and substituted ammonium
polyacetates, carboxylates, polycarboxylates, polyacetyl
carboxylates and polyhydroxysulphonates. Specific examples
include sodium, potassium, lithium, ammonium and substituted
ammonium salts of ethylenediaminetetraacetic acid,
nitrilotriacetic acid, oxydisuccinic acid, melitic acid,
benzene polycarboxylic acids and citric acid.
It is preferred that the compositions according to the
- 1335~88
invention be alk~l Ine, that is at the concentration of 1 g/l
in distilled water at 25C the pH should be at least 8,
preferably at least 10. To this end the compositions may
include a water-soluble alk~l~ne salt. This salt may be a
detergency builder or a non-building alkaline material.
Apart from the ingredients already mentioned, a number
of optional ingredients may also be present.
Examples of other ingredients which may be present in
the composition include fabric softening agents such as
fatty amines, fabric softening clay materials, lather
boosters such as alkanolamides, particularly the
monoethanolamides derived from palm kernel fatty acids and
coconut fatty acids, lather depressants, oxygen-releasing
bleaching agents such as sodium perborate and sodium
percarbonate, peracid bleach precursors, chlorine-releasing
bleaching agents such as trichloroisocyanuric acid,
inorganic salts such as sodium sulphate, and, usually
present in very minor amounts, fluorescent agents, perfumes
including deodorant perfumes, enzymes such as proteases,
cellulases, amylases and lipase, germicides and colourants.
The detergent compositions according to the invention
may be prepared by a number of different methods according
to their physical form. In the case of granular products
they may be prepared by dry-mixing or coagglomeration. A
preferred physical form is a granule incorporating a
detergency builder salt and this is most conveniently
manufactured by spray-drying at least part of the
composition. In this process a slurry is prepared
containing the heat-insensitive components of the
composition such as the surfactant system, builder material
and filler salt. The slurry is spray-dried to form base
powder granules with which any solid heat-sensitive
ingredients may be mixed, such ingredients including
bleaches and enzymes. The specified nonionic surfactants
can be liquified by melting or solvent dissolution and
9 1335~88
sprayed onto the base powder granules, rather than including
them in the slurry for spray-drying. The invention will now
be described in more detail in the following non-limiting
examples.
EXAMPLES 1 T0 6
Wash liquors were prepared in water having a hardness
of 25 FH (equivalent to a free calcium ion concentration of
2.5 x 10- 3 molar). The wash liquor contained the equivalent
of 6 g/l of a composition contAining (by weight):
10 Specified anionic surfactant 9%
Specified nonionic surfactant 4%
Sodium tripolyphosphate 23%
Sodium carbonate 6%
Sodium alkaline silicate 5.5%
15 Sodium sulphate 30.8%
Sodium chloride 2.93%
Water --- balance ---
The sodium chloride was included as being equivalent
in ionic strength to 5% sodium perborate monohydrate which
would be present in practice. The bleach is left out of
these experiments in order to avoid confusion between
detergency and bleaching effect in the interpretation of the
results.
The wash liquors were used to wash a fabric load at
liquor to cloth ratio of 50:1. The load included a number
of polyester monitors to which had previously been applied
an amount of C1 4 tagged triolein. Measurement of the level
of tagged triolein after washing, using stAnAArd radio-
tracer techniques, gives an indication of the degree of
detergency, i.e. soil removal, obtA i neA .
The wash time was 20 minutes with an agitation of 70
rpm. Washes were isothermal at temperatures as specified
1~3S488
below.
The anlonlc surfactants used were as set out ln the
followlng table:
Chaln Length Dlstrlbutlon (%)
5 Surfactant <C8 C~ 2 Cl 8 <C~ ~ Orlgln
ELFAN 2801 0 53 120 Coco~l~t
ELFAN KT5501 0 27 380 Coco/tallow mix
* SULFOPON T552 0 0 700 Tallow
1 - ex Akzo
2 - ex Henkel
In Examples 1 to 6 the nonionic surfactant was
* SYNPERONIC A7 (ex ICI) which is princlpally Cl 3 /Cl 5 alcohol
ethoxylated with an average of 7 moles of ethylene oxlde.
This nonionic surfactant has an HLB of 11.7.
The results obtalned were as follows:
Wash % Soil
Example No Anionic Temperature Removal
1 ELFAN 280 30C 24.9
2 ELFAN KT550 30C 30.0
3 SULFOPON T55 30C 24.9
4 ELFAN 280 60C 30.5
ELFAN KT550 60C 36.3
6 SULFOPON T55 60C 46.7
From these results lt ls apparent that at 60C ELFAN
KT550 outperforms the coconut only derlved PAS, ELFAN 280.
At the lower temperature of 30C, ELFAN KT550 outperforms
both the coconut only and the tallow derlved materlals.
* denotes trade mark
`~''
11 1335~88
EXAMPLES 7 TO 12
Examples 1 to 6 were repeated, except that the
nonionic surfactant was a mixture of 1 part SYNPERONIC A7
with 3 parts of SYNPERONIC A3, which is a similar material
in which the alcohol is ethoxylated with an average of 3
moles ethylene oxide per molecule. This nonionic surfactant
mixture has an HLB of approximately 9Ø
The results were as follows:
Wash ~ Soil
10 Example No Anionic Temperature Removal
7 ELFAN 280 30C 39.0
8 ELFAN KT550 30C 38.7
9 SULFOPON T55 30C 30.4
ELFAN 280 60C 44.6
11 ELFAN KT550 60C 49.8
12 SULFOPON T55 60C 54.4
From these results it is apparent, as with Examples 1
to 6, that at 60C ELFAN KT550 outperforms the coconut only
derived PAS, ELFAN 280. At the lower temperature, ELFAN
KT550 outperforms the tallow only derived PAS, SULFOPON T55,
while not being significantly different in performance to
the coconut only derived material.
A comparison of the results in Examples 7 to 12 with
those in Examples 1 to 6 demonstrates the preference for
utilising a nonionic surfactant with a lower HLB.
EXAMPLES 13 TO 24
Examples 1 to 3 were repeated but the levels and
proportions of the surfactants were varied. The variations
in composition and the results are set out in the list below
in which "A3" and "A7" denote SYNPERONIC A3 and SYNPERONIC
A7. The wash temperature was 30C in each instance, as with
Examples 1 to 3.
12 1335488
% Soil
Example No Anionic Nonionic Removal
13 12% ELFAN 280 1.33% A7 + 4% A3 42.9
14 12% ELFAN KT550 1.33% A7 + 4% A3 43.7
12% SULFOPON T55 1.33% A7 + 4% A3 34.5
16 9% ELFAN 280 2% A7 + 3% A3 37.3
17 9% ELFAN KT550 2% A7 + 3% A3 36.8
18 9% SULFOPON T55 2% A7 + 3% A3 32.3
19 9% ELFAN 280 3% A7 + 3% A3 35.2
9% ELFAN KT550 3% A7 + 3% A3 37.2
21 9% SULFOPON T55 3% A7 + 3% A3 33.0
22 9% ELFAN 280 4% A7 + 3% A3 34.3
23 9% ELFAN KT550 4% A7 + 3% A3 36.1
24 9% SULFOPON T55 4% A7 + 3% A3 33.2
It will be seen that in every case, the ELFAN KT550
outperformed the all tallow SULFOPON T55 and came close to
or surpassed the all coconut ELFAN 280. In every case, this
amounts to a soil removal which is better than the average
of the figures for the all coconut and all tallow derived
materials.
EXAMPLES 25 TO 31
Wash liquors were prepared in water of 30FH
(equivalent to a free calcium ion concentration of
3.0 x 10- 3 molar). The wash liquor contained the equivalent
of 6g/l of a composition containing (by weight):
Specified surfactant 13%
Zeolite 24%
Polyacrylate 4%
Sodium sulphate 20.6%
30 Sodium carbonate 12%
Water --- balance ---
Each wash liquor composition was employed to launder
13 1335488
several test cloths in a Tergotometer, in a heat-up cycle to
60C. After laundering the increase in reflectance of the
test cloths was measured.
The test cloths employed had various stains as
follows:
EMPA-104 : Stain of Indian ink and olive oil.
WFK-lOC : Stain predominantly wool fat, with minor amounts
of kaolin, carbon black and iron oxide.
PC-9 : Stain of ground nut oil, Indian ink and iron
oxide.
The specified surfactant(s) consisted of some or all
of hardened tallow alcohol sulphate (TAS) and/or coconut
alcohol sulphate (CAS) and mixtures with nonionic surfactant
(NI) which was SYNPERONIC A3, i.e. Cl 3 /Cl 5 fatty alcohol
ethoxylated with an average of 3 moles of ethylene oxide per
molecule.
Results were as follows:
Example
No Surfactant(s) Increase in Reflectance
WFK-lOC PC-9 EMPA-104
100% TAS 0% CAS 17.1 18.9 21.5
26 60% TAS 40% CAS 21.8 19.3 24.3
27 40% TAS 60% CAS 23.7 19.7 22.2
28 0% TAS100% CAS 18.4 17.9 20.6
29 20% NI80% TAS0% CAS 20.0 19.8 17.9
20% NI40% TAS40% CAS 24.6 21.0 20.3
31 20% NI0% TAS80% CAS 19.2 18.9 16.9
It will be seen that in each case the mixture of
hardened tallow based and coconut based surfactants gave
better detergency than either of them used alone.
14 1335488
EXAMPLES 32 AND 33
Wash liquors were prepared in water having a hardness
of 25 FH. The wash liquors cont~ne~ the equivalent of 6
g/l of a composition cont~ n~ ng ( by weight):
5 Ingredient % by weight
Specified anionic 9
SYNPERONIC A7
SYNPERONIC A3 3
Zeolite 26.6
10 Sodium sulphate 19.5
Sodium carbonate 14.0
Sodium silicate 1.3
Sodium chloride 3.0
Moisture --- balance to 100% ---
For Example 32 the anionic surfactant was ELFAN KT550.
For Example 33 the anionic surfactant was PAS derived from
myristyl alcohol (i.e. C1 4 alcohol). The wash liquors were
tested as in Examples 1 to 6, although a different grade of
polyester was used for the test cloths.
Soil removal results were:
Example 32 (ELFAN KT550) 28.1%
Example 33 (Cl 4 PAS) 26.0
EXAMPLE 34
The following formulation was prepared by spray drying
a slurry of some of the ingredients to form a base powder
and then subsequently spraying on some of the nonionic
surfactant and post dosing the remaining ingredients.
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Ingredients Parts by weight
Base powder
Anionic (see below) 9.0
SYNPERONIC A7 1.0
5 Zeolite 26.6
Sodium sulphate 19.5
Sodium carbonate 2.0
Moisture and miscellaneous 13.7 71.8
Spray-on
10 SYNPERONIC A3 1.0 1.0
Post-dose
Sodium silicate 1.3
Sodium perborate monohydrate 8.0
SYNPERONIC A3 2.0
15 TAED granules 2.8
Antifoam 3.0
Enzyme 0.6
Perfume 0.3
Sodium carbonate 12.0 30.0
20 Total 102.8
This composition was used to wash a variety of stained
fabrics under a variety of conditions, results being
assessed by measuring the reflectance of treated monitors.
The anionic surfactants used were tallow PAS, coconut PAS
and a 50/50 mixture of the two.
The benefits observed in previous Examples were again
observed in this case also. Thus the 50/50 mixture
generally gave better performance than the coconut PAS
alone, while on a number of stains (notably dirty motor oil,
and make-up on white cotton) the mixture out-performed both
alternatives.
