Note: Descriptions are shown in the official language in which they were submitted.
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- 1 - C 557 (R)
LIQUID DETERGENT COMPOSITION
This invention relates to a liquid detergent composition with
improved c~eaning performance. More particularly the invention
relates to an improved liquid detergent composition which is
especially suitable for the manual cleaning of dishes, glasses,
kitchen utensils, cutlery and the like. The liquid detergent
composition of the invention contains juice of a citrusfruit,
such as lemon juice.
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Liquid detergent compositions containing lemon juice are known
in the art. US Patent Specification No. 3,650,968 describes
cleaning compositions for removing fish odours comprising
30-80% by weight of water, 0.1-35% by weight of detergent and
0.1-15~ by weight of citrus (lemon) juice. These li~uid
detergent compositions, however, have very poor dishwashing
properties and cannot therefore be used satisfactorily for the
cleaning of dishes, glasses, kitchen utensils, cutlery and the
like.
It is an object of the present invention to provide an effective
liquid dishwashing detergent composition which is moreover
particularly effective against difficult soils.
It is a further object of the present invention to provide a
method for the removal of difficult soils from dishes, pots and
pans and other kitchen utensils.
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By "difficult soils" is meant here the difficult end of the dish-
washing spectrum, such as baked-on proteins and starch soils.
These and other objects of the invention, which will be apparent
hereinafter, can be achieved by combining an organic synthetic
surfactant system of at least two surfactants as defined below
with a citrus juice at a level of from 5% by weight based on
the total composition. Any juice of a citrus fruit belonging
to the general class of citrus fruits can be used, such as:
sweet oranges (citrus sinensis); sour or bitter oranges
(citrus auranticum); mandarins (citrus reticulata); grapefruits
(citrus paradisi); pumelos (citrus grandis); lemons (citrus
limon~; limes (citrus aurantifolia); citrons (citrus medica);
papeda (citrus hystrix) and trifoliate oranges (citrus
trifoliata), though lemon juice in view of its established
consumer's acceptance will be preferred in the invention.
Unless otherwise indicated the percentages of fruit juices given
in this specification refer to fruit juices of single strength.
The term "single strength" is used here to indicate the average
strength of fruit juice sgueezed out from fruit.
If concentrated juices are used, these will be indicated by
; designating the strength factor, e.g. "4x concentrate".
The compositions of the present invention are therefore
especially designed for general use in conventional dishwashing,
which can be used in the concentrated aqueous form or in the
conventional hi~hly dilute dishwashing operation, producing a
good cleaning effect combined with a consumer-acceptable foam
level and foam stability.
Accordingly the liquid detergent composition of the invention
comprises from about 5-60% by weight of an organic synthetic
surfactant system of at least two surfactants as defined below,
and at least 5% by weight of a citrus juice.
The organic synthetic surfactant system consists of
1) from about 30-90 parts by weight of the surfactant system of
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a Ca-sensitive first surfactant selected from the group consisting
of water-soluble C -C16-alkyl benzene sulphonates, alkane sulphonates
having 8-20 carbon atoms, olefin sulphonates having from
8-20 carbon atoms, di-C8 20-alkyl sulpho-succinates, di-C6 12-
alkyl phenol sulphosuccinates, primary and secondary alkyl
sulphates having 8-20 carbon atoms, C8 20-alkyl polyethoxy
sulphates having 1-25 ethoxy groups, and mixtures thereof,and
2) from about 70-10 parts by weight of said system of a less
Ca-sensitive second surfactant selected from the group consisting
of water-soluble nonionic condensation products obtained by condens-
ing from 5-30 moles of an alkylene oxide, preferably ethylene or
propylene oxide, with one mole of an organic hydrophobic compound,
aliphatic or alkyl aromatic in nature, having 8-24 carbon atoms and
at least one reactive hydrogen atom, particularly a reactive
hydroxyl, amino, amido or carboxyl group; C8 20-alkyl sulphobetaines;
amine oxides containing one long chain alkyl moiety of from 10-28
carbon atoms and two moieties which can be either alkyl radicals or
hydroxyalkyl radicals having from 1 to 4 carbon atoms; C8 20-alkyl
polyethoxy sulphates having 1-25 ethylene oxide groups, and mixtures
thereof,
said surfactants (1) and the ion-active surfactants of group (2)
being present in the form of their alkali metal salts, ammonium
salts, or mixtures thereof.
Examples of nonionic water-soluble condensation products
obtained by condensing 5-30 moles of an alkylene oxide with one
mole of an organic hydrophobic compound are:
a) the condensates of ethylene oxide with aliphatic straight
chain or branched chain, primary or secondary alcohols of more than
8 carbon atoms such as those derived from tallow or coconut fatty
acids, containing 5-20 ethylene oxide groups, and branched chained
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Cl1-C15 alcohols condensed with 5-20 ethylene oxide groups.
b) the condensates of ethylene oxide with alkylphenols, in which
the phenols may be mono- or polyalkylated and the
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total number of carbon atoms in the side chain or chains is
from 5 to 18. Specific examples are condensates of one mole
nonyl phenol with 8 to 15 moles of ethylene oxide.
c) the condensates of ethylene oxide with fatty acid esters,
preferably mono-fatty acid esters of the sugar alcohols,
sorbitol and manitol.
d) polyethenoxyesters obtained by reacting ethylene oxide with
carboxylic acids, the latter being natural fatty acids or
synthetic fatty acids made from oxidised paraffin wax
having from 8-20 carbon atoms or alkylbenzoic or naphthenic
acids having from 5-18 carbon atoms in the alkyl chain.
e) the condensation products of fatty acyl alkanolamides of the
type C7 17 alkyl-C0-NHC2H40H, C7_17 alkyl-CO-N(C2H40H)2
with ethylene oxide.
f) the condensation products of C8 18 alkyl-, C8 18 alkenyl-
and C8 18 alkylaryl amines with ethylene oxide.
A specific example is the condensation product of one mole of
a dodecylamine with 9-12 moles of ethylene oxide.
Specific examples of amine oxides are dimethyl dodecyl amine
oxide, diethyl tetradecyl amine oxide, bis-(2-hydroxyethyl)-
dodecyl amine oxide, and dimethyl-2-hydroxydodecyl amine oxide.
It has been discovered that the above defined surfactant system
can be utilised effectively in combination with citrus juice,
particularly lemon juice, in the above stated proportions, to
provide the desirable combined effect of good detergency, good
; foam behaviour and enhanced per'ormance on difficult soils,
particularly baked-on or dried-on proteins or starchy soils,
over a wide pH range from practically acid pH to alkaline pH,
e.g. from 4-10. A preferred pH range of the composition of the
invention is from about 5.5 to 9, particuarly from 6-8.5, more
particularly from 7-8.5.
Any combination of the above-described first and second sur-
factants can be used to form the organic synthetic surfactant
system in the composition of the invention.
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-S- C 557 (R)
Typical examples of surfactant systems are alkyl benzene
sulphonate/alkyl polyethoxy sulphate mixtures; alkyl benzene
sulphonate/alkyl polyethoxy sulphate/nonionic mixtures; alkyl
sulphate/alkyl benzene sulphonate/alkyl polyethoxy sulphate
mi~tures and alkyl sulphate/alkyl polyethoxy sulphate/amine oxide
mixtures.
As explained above, any type of citrus juice at a level of from
5~0 by weight can be used in the present invention, lemon, lime,
orange and grapefruit juices being representative of the
general class. The minimum amount of 5% by weight of citrus juice
is taken since at lower levels the effect is insignificant to
practically zero. Although any proportion above 5% of citrus
juice as practically possible can in principle be used, it was
found that high levels are not necessary to achi~e the desired
benefit. Besides, as there is a clear fall-off in the increase
in performance improvements with increasing juice content above
10%, and a quick fall-off especially in the higher percentage
region, the use of too high levels of juice will not justify
the extra high expenses incurred. Advantageously 50~, preferably
25%,can be taken as a convenient practical upper level of single
strength citrus juice in the composition of the invention, as at
concentrations above these percentages citrus iuice provides no
further advantages that would compensate the high costs of extra
citrus juice.
A citrus juice level most advantageously used in the liquid
detergent composition of the invention is from 5% to about 10%
by weight.
Accordingly the invention provides an aqueous liquid detergent
composition especially adapted for dishwashing and having
improved cleaning performance particularly on difficult soils,
comprising 5-60% by weight of an organic synthetic surfactant
system consisting of at least two surfactants as defined here-
inbefore, and 5-50% weight of a citrus juice.
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Citrus juices are availble on the market. They are generally
presented as either single strength juices or as concentrates of
various strengths, i.e. from 2x concentrates
up to 10x concentrates. Lemon juice contains a
number of different classes of chemical compounds including
acids, sugars, amino acids, oils and trace elements. Analytical
data on citrus juices can be found in the following literature
references:
a) "Chemical Constituents of Citrus Fruits", SUPD. 2 (1970)
by Kefford and Chandler;
2) "Biochemistry of Fruits and their Products", Vol. 1 (1970)
Ed. A.C.Hulme.
Within each class there are several different constituents
each separately capable of being determined analytically. The
main acid in citrus juice is citric acid, which is present at a
level of about 5-6% by weight.
It is not known exactly which of the constituents present in
citrus juice are responsible for improving the cleaning effect,
but it is believed that a synergistic effect is produced by the
combination of one or more constituents present in citrus juice
and the active system used in the composition of the invention.
In addition to the above-described essential ingredients the
liquid detergent composition of the invention can optionally
contain other nOn-essential materials. Such optional
ingredients include additional surfactants other than those
specified as first and second surfactants of the organic
synthetic surfactant system; builder salts which can be added
to promote the cleaning and soil-removal efficiency of the
surfactants of the composition, e.g. phosphates, polyphosphates,
phosphonates, carbonates, polyacetates and polycarboxylates;
lather promoting agents, such as coconut fatty acid diethanol
amide; hydrotropes and solubilising agents, such as the lower
alkanols containing 2-4 carbon atoms, especially ethanol, urea,
sodium or potassium toluene sulphonate and sodium or potassium
xylene sulphonate, which are generally added to promote phase
stability especially of compositions with high concentrations
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-7- C 557 (R)
of surfactants; preservatives; perfume and colouring agents.
Furthermore, as desired, acid or alkaline substances for pH
adjustment and also scouring agents may be incorporated in the
detergent composition of the invention.
Preferred compositions are those which contain 10-50% by weight
of the above-described organic synthetic surfactant system,
5-25% by weight of lemin juice and about 15-75% by weight of
water. Particularly preferred are those having an active
detergent content of more than 35% by weight.
The invention will now be illustrated by the following
Examples:
Examples I-III
The following compositions were prepared:
Composition I II III A B
/O by weight
sodium dodecyl benzene 29.0 29.0 29.0 29.0 29.0
sodium lauryl-(ethXY)3-14.0 14.0 14.0 14-0 14-0
sodium citrate - - - - 1.0
lemon juice 1.25 2.5 5.0 0.25 0.25
(4x concentrate)
ethanol 5.5 5.5 5.5 8.0 7.0
urea 5.5 5.5 5.5 7.5 8.0
water + preservatives44.7543.5 41.0 41.25 40.75
To determine the relative ease of cleaning of baked-on soils
from substrates after soaking, the following half-tile
comparison test method was used:
Soiled substrates, in the form of square enamel tiles
(10 x 10 cm) are immersed in solutions of the test products
(1 litre) at 0.15% concentrations. The solution is at 45C
at the start of the test and is reheated when it drops to
40C (use a small immersion coil). The tiles are checked for
the first indications that the soil on one of them has
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softened and then all are removed from the test solution and
cleaned (immersion time varies between 5-50 mins). Cleaning is
carried out for 30 seconds using a Brillo Swish sponge dipped in
the appropriate test solution.
The soil and soiling method:
The testswere carried out using Fruit Pie filling (Cherry and
Apricot) and a mixture of flour and fruit pie filling (1:4~.
The pie filling is finely mushed by pressing it through a 240
micron sieve and a fine paste is produced from the flour/pie
filling mixture.
The soil is applied to the substrate by screen printing, using
two passes. The s~il is then baked in the centre of a large
oven (Gallenkamp Oven Model OV330) for 4 minutes. Temperature
should be 250C before putting the soiled substrates into the
oven and speed in putting them into the oven is desirable to
avoid the temperature dropping below 220C.
Results:
These are set out fully in Table 1 below.
Assessment was made by a technician panel rating the degree
of soil removal on the following basis:
O = completely clean
1 = still slightly soiled
2 = moderately soiled
3 = considerably soiled
4 = no visible cleaning.
The ratings were averaged from 8 results for each product and
control. Product A was used as control.
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TABLE 1
Average Rating Difference (control-sample)
Product in 5H water in 26H water in 5H water in 26H water
I 2.13 2.93 + 0.81 + 0.81
5control (A) 2.94 3.74
II 1.25 3.31 + 0.44 + 0.32
control (A) 1.69 3.63
10III 1.00 2.18 + 0.88 + 0.44
control (A) 1.88 2.62
B 0.75 2.62 - 0.12 - 0.37
control (A) 0.63 2.25
From the above results it is clear that the lemon juice
compositions I, II and III of the invention are superior to
compositions A and B outside the invention.
Example IV
The influence of pH was investigated from assessing the perfor-
mance of the following liquid composition in a soaking test.
Composition
sodium dodecyl benzene sulphonate 29.0%
C12 alkyl ether sulphate containing 3 ethylene oxide 14.0%
lemon juice 10.0%
ethanol . 5.5%
urea 5.5%
water + preservatives 36.0%
Comparisons were carried out by using the standard (10 x 10 cm)
enamel tiles soiled with Apricot pie filling/flour and baked
as in Examples I-III. Half tile comparisons in water of 11.3
German Hardness were carried out at 45C.
Test products were tested in a random manner and all tests were
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duplicated.
pH Adjustments were carried out at 45C using dilute sulphuric
acid (0.1 M) and dilute sodium hydroxide (0.1 M) solutions and
measurement of the pH at the end of each test was also made.
A product of the above nominal composition without lemon juice
was used as control.
Assessment was made by a technician panel to assess the degree
of soil remaining on each half tile using the following ratings:
0 = completely clean
1 = still slightly soiled
2 = moderately soiled
3 = considerably soiled
4 = no visible cleaning.
These ratings have been averaged ( 6 results for each test product
andcontrol at each pH value) and a soil difference between the
control and the test product calculated.
TABLE I
Results of soaking ~st - a comparison of product with and without
10% lemon juice.
pH Product Ratings Average Difference
control-sample
5.5 lemon 1.5 2.5 1. 0.5 1. 0.5 1.17 +0.75
control 2.5 3. 1.5 1.5 2. 1. 1.92
7.0 lemon 3. 3.5 2.5 0 0 0 1.5 +0.67
control 3.5 4. 3. 0.5 1. 0.5 2.17
.5 lemon 0.5 0.5 0.5 0.5 1. 0.5 0.58 +1.42
control 1.5 2. 1. 2.5 3. 2. 2.0
10.0 lemon 1.5 2.5 1. 1.5 2.5 1. 1.67 +0.50
control 3. 3. 1.5 2. 2.5 1. 2.17
The above Table shows that the composition of the invention shows
a consistent superiority at pH 5.5, 7.0, 8.5 and 10.0, with
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results at pH 8.5 being particularly good.
Example V
The following compositions were assessed:
% by weight
Composition C V1 V2 V3 V4 V5 V6
sodium dodecyl ben- 29 0 29.0 29.0 29.0 29.0 29-0 29-0
zene sulphonate
lauryl-3-ethoxy- 14.0 14.0 14.0 14.0 14.0 14.0 14.0
lemon juice 0.25 1.25 2.5 3.75 5.06.25 12.5
(4x concentrate)
ethanol 10.0 10.0 10.0 10.0 10.010.0 10.0
urea 10.0 10.0 10.0 10.0 10.010.0 10.0
- 15 water+ to to to to to to to
preservative100.0 100.0 100.0 100.0 100.0 100.0 100.0
nominal lemon1 5 10 15 20 25 50
juice level
The method employed was as follows:
1. An egg soiling was prepared by carefully mixing dried egg
powder and water in a ratio of 1:1.
2. A 5 cm strip of soil was screen-printed on to the centre
of a 30 x 25 cm glass tile.
3. Tiles were baked for 30 mins at 20nc.
Five assessments could then be carried out across each
tile. At least two control assessments were carried out
on each tile.
4. Five 5 cm wells were built across the tile using plasticine
strips. 6 mls of solution (0.15%) were placed in a well.
Using a J cloth covered head and a 1.5 kg weight, the
number of rubs to clean the 5 cm strip of soil was recorded.
5. Results for the test solution were calculated as a per-
centage of the performance of the nearest control in the
tile.
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The results of the tests using water of 5H are tabulated below:
Composition /0 Lemon juice Average performance as % control
Control (C) 1 100
V1 5 89
V2 10 61
V3 15 70
V4 20 73
V5 25 68
V6 50 . 60.5
The above results clearly show the superior performance of the
compositions V1 to V6 of the invention, containing 5' to 50%
lemon juice respectively, on cleanin~ baked-on egg, over the
control.
Example VI
The following compositions were compared in a standard plate
washing test for their dishwashing performance as well as in
a test to determine the relative ease of cleaning baked-on
soils from substrates after soaking, using the test method as
described in Examples I-III.
Composition Vl Composition D
- 25 10~ sodium dodecylbenzene sulphonate 15' Empilan~LP 10
5' sodium lauryl (ethoxy)3-sulphate 30~c glycerin
5o lemon juice 5% lemon juice
2'~, urea 2% urea
balance water balance water
Empilan LP10 is a nonionic fatty amide condensate, comparable
to Nopco 1179 of the Nopco Chemical comPany~
Empilan is a Registered Trade Mark of Marchon Products Ltd.
The standard plate washing tests were carried out using the
following test conditions:
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Product concentrations: 0.15% and 0.45%
Temperature of solution: 45C
Standard gravy soil at 5g/plate: fat, starch, oleic and
stearic acids.
The results are tabulated below:
TABLE 3
Number of plates washed
Water hardness 5H 26H
Product concentration 0.15% 0.45% 0.15% 0.45%
Composition VI (pH 7) 30 63 27 59
Composition D (pH 5.8) 3 7 2 4
Results of the test to determine the relative ease of cleaning
baked-on soils from substrates. The ratings were arranged from
5 results for each product used at 0.75% concentrations.
TABLE 4
Average rating Difference
Composition in 5Hwater in 26H water in 5Hwater in 26Hwater
VI (pH 7) 0.2 2.4
D (pH 5-8) 0 72.4 + 0.5 + 0.0
VI (pH 7) 0.73.0
D (pH 7) 1.13.3 + 0.4 + 0 3
VI (pH 7) 2.4
D (pH 5.8) 2.7 ~ + 0.3
VI (pH 7) 1.5
D (pH 7) 2.1 + 0.6
The above results clearly show the superior properties of
composition VI of the invention over comDosition D of the art in
both dishwashing and baked-on soil performance.
Examples VII-IX
The following liquid dishwashing formulations are within the scope
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of the invention:
Composition VII % by weight
sodium dodecyl benzene sulphonate 16.0
nonyl phenol-7 ethylene oxide 7.0
ethanol 2.0
urea 4.0
lemon juice 8.0
water + preservatives to 100.0
Composition VIII % by weight
ammonium dodecyl benzene sulphonate32.0
nonyl phenol-10 ethylene oxide 8.0
ethanol 3.0
15 urea 3.0
sodium xylene sulphonate 9.0
lemon juice 7.5
magnesium sulphate 1.2
water + preservatives to 100.0
Composition IX
sodium lauryl (ethoxy)3-sulphate 24.0
dimethyl dodecyl amine oxide 5.0
lemon juice 10.0
25 sodium citrate 1.0
urea 3.0
ethanol 3.0
water + preservatives to 100.0
