Note: Descriptions are shown in the official language in which they were submitted.
~Z~293 C 816 (R)
LIQUID DETERGENT COMPOSITIONS
The present invention relates to liquid detergent com-
positions and in particular to aqueous liquid deter-
gent compositions having improved non-corrosive
properties.
It i5 desirable to include an anti-corrosion agent in
detergent compositions in order to inhibit the corro-
sive and discolouring influence of the washing liquid
on metal or enamel parts of washing machines and to
prevent thereby the malfunctioning of the machines or
the discolouring of fabrics which come into contact
with such corroded parts.
Aqueous liquid detergent compositions containing
corrosion inhibiting agents are known in the art.
Generally used are soluble silicates, such as meta-
silicate, orthosilicate and sesquisilicate. Apart from
their corrosion inhibiting action, such compounds
provide the liquid detergent composition with a highly
alkaline environment, which i5 not always a desirable
circumstance, especially if in such compositions alka-
li-sensitive ingredients are used. Further anti-
corrosive agents described in the detergent art include
sulphites, nitrites, carbonates, borax or organic com-
pounds such as benzoates.
It has now been found that the corrosive action ofaqueous liquid detergent compositions can be reduced
to a significant extent by incorporation of silica of
such type and in such amount that in the wash liquor a
certain threshold concentration of dissolved silica is
established.
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Accordingly the present invention provides aqueous
liquid detergent compositions with improved non-
corrosive properties, comprising conventional
detergent ingredients and an effective amount of
silica of the type to be defined hereafter.
It has been found that in order to achieve optimal
anti-corrosion protection the silica must be present
in the wash liquor in a dissolved form at a concentra-
tion of at least 120 ppm by weight and preferably 150
ppm by weight. According to the presen-t invention
therefore, in order to provide the required amount of
dissolved silica in the wash liquor to ensure adequate
anti-corrosion protection, the silica will in general
be incorporated in the liquid detergent composition
in an amount which is the equivalent of from about 1%
to 10% by weight, preferably from 1.5% to 5% by weight
and most preferably from 2~ to 4% by weight of the
liquid detergent composition which is intended for use
at an in-wash product dosage of 10 g/l.
If a liquid detergent composition is formulated having
a preferred in-wash product dosage which is different
from 10 g/litre, the amount of silica that should be
incorporated to achieve adequate anti-corrosion
protection must be adjusted accordingly, such that the
amount thereof corresponds with the ranges as defined
for 10 g/l product dosage.
The silica to be used in the present invention should
have a surface area which is greater than 200 m2 per
gram and preferably greater than 350 m2 per gram or
even 500 m2 per gram. The upper limi~ of the surface
area is not a cri~ical factor, but normally surface
areas range to about 1200 m2 per gram.
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In general such sili.cas have elementary particle sizes
of less than about 30 nm, i.n particular less than
about 25 nm. Preferably, elementary parti.cle sizes are
less than 20 nm or even 10 nm. There is no criti.cal
lower li.mit of the elementary particle size; the lower
limi.t is governed by other factors such as the manner
of manufacture etc. In general, commerci.ally available
si.li.cas have elementary parti.cle sizes of 1 nm or more.
Suitable forms of silica include amorphous si.li.ca,
such as precipi.tated sili.ca, pyrogeni.c sili.ca and si.l-
i.ca gels, such as hydrogels, xerogels and aerogels, or
the pure crystal forms quartz, tridymite or crystobal-
i.te, but the amorphous forms of sili.ca are preferred.
Suitable sili.cas may readily be obtained commercially.
They are sold, for instance, under the Regi.stered
Trade Names of Aerosil 380 (ex Degussa Corp., ~.J.,
USA), Cab-0-Sil M5 (ex Cabot Corp., Ill, USA), Tixosi.l
38A (ex SI Chi.mie, France) and Gasil 200 tex Crosfi.eld,
UK).
The liquid detergent composi.tions of the i.nventi.on
further comprise as essenti.al ingredient an active de-
tergent material, which may be an alkali metal or al-
kanolami.ne soap of ClO-C24 fatty aci.d, including
polymeri.zed fatty acids, or an anioni.c, noni.onic, cat-
ioni.c, zwi.tteri.oni.c or amphoteric synthetic detergent
material, or a mixture of any of these. The anionic
synthetic detergents are synthetic detergents of the
sulphate- and sulphonate-types. Examples thereof are
salts (i.ncluding sodi.um, potassium, ammoni.um and sub-
sti.tuted ammonium salts, such as mono-, di- and tri-
ethanolamine salts) of Cg-C20 alkyl benzene sulphon-
ates, C8-C22 primary or secondary alkane sulphonates,
C8-C24 olefi.n sulphonates, sulphonated polycarboxylic
aci.ds, prepared by sulphonati.on of the pyrolized product
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of alkali.ne earth metal ci.trates, e.g. as described in
Bri.ti.sh Patent Speci.ficati.on No. 1 082 179, C8-C22 al-
kyl sulphates, C~-C24 alkyl polyglycol ethersulphates,
(containi.ng up to 10 moles of ethylene oxides), further
examples are described in "Surface Acti.ve Agents and
Detergents" (Vol. I and II) by Schwartz, Perry and
Berch.
Exa~nples of nonioni.c syntheti.c detergents are the con-
densati.on products of ethylene oxi.de, propylene oxi.de
and/or butylene oxide with C8-C18 alkylphenols, C8-C18
primary or secondary ali.phatic alcohols, C8-C18 fatty
aci.d ami.des; further examples of noni.oni.cs i.nclude ter-
tiary ami.ne oxi.des wi.th one C8-C18 alkyl chain and two
Cl-C3 alkyl chai.ns. The above reference also describes
further examples of nonioni.cs.
The average number of moles of ethylene oxide and/or
propylene oxi.de present i.n the above nonioni.cs vari.es
from 1 to 30; mixtures of various nonioni.cs, includi.ng
mi.xtures of nonioni.cs wi.th a higher degree of alkoxyl-
ati.on, may also be used.
Examples of cati.onic detergents are the quaternary am-
monium compounds such as alkyl dimethyl ammoni.um halo-
genides.
Examples of amphoteric or zwi.tterionic detergents are
N-alkylamino acids, sulphobetaines and condensation
products of fatty aci.ds with protein hydrolysates, but
owing to their relatively hi.gh cost they are usually
used in combination wi.th an anionic or a nonionic de-
tergent. Mixtures of the various types of active de-
tergents may also be used, and preference is given to
mixtures of an anioni.c and a nonionic detergent-active
compound. Soaps (in the form of thei.r sodium, potas-
si.um, and substi.tuted ammoni.um salts,such as of poly-
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merized fatty acids, may also be used, preferably inconjunction with an ani.onic and/or a nonionic synthet-
i.c detergent.
The amount of the acti.ve detergent material varies
from 1 to 60%, preferably from 2 to 40~ and particu-
larly preferably from 5 to 25~ by wei.ght. When a soap
i.s i.ncorporated, the amount thereof is from 1 to 40
by weight.
Although not necessarily, the li.qui.d compositions of
the invention preferably also comprise up to 60~ of
suitable builder materials, such as sodium, potassium
and ammonium or substituted ammoni.um pyro- and tri-
polyphosphates, -ethylenediamine tetraacetates, -ni.-
trilotriacetates, -ether polycarboxylates, -citrates,
~carbonates, -orthophosphates, zeolites, carboxy-
methyloxysuccinates, etc. Particularly preferred are
the polyphosphate bui.lder salts, nitri.lotriacetates,
ci.trates, zeoli.tes, and mixtures thereof. In general
the builders are present i.n an amount of from 1 to
60~, preferably from 5 to 50% by weight of the final
compositi.on.
The amoun`c of water present in the detergent composi.-
tions of the invention varies from 10 to 70~ by wei.ght.
Other conventi.onal materials may be present i.n the
liquid detergent composi.tions of the invention, for
example sequestering agents, such as ethylenediami.ne-
tetraphosphonic aci.d; non-builder electrolytes, such
as alkali.metal-chlorides, -bromides, -nitrates and
-sulphates; soil-suspending agents, such as sodium
carboxymethylcellulose, polyvinylpyrrolidone or the
maleic anhydride/vinylmethylether copolymer; hydro-
tropes; dyes; perfumes; alkaline materials, such as
sili.cates; optical brighteners; germi.cides; anti-
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tarnishing agents; suds boosters; suds depressants,
such as li.quid polysiloxane anti.-foam compounds; en-
zymes, parti.cularly proteolytic enzymes, such as the
commerci.ally ava;.lable subti.li.sins Maxatase ~ (ex Gi.st-
Brocades N.V., Delft, The Netherlands~, Alcalase ~ andEsperase ~ (both ex Novo Industri A/S, Copenhagen, Den-
mark), amylolyti.c and cellulolyti.c enzymes; enzyme sta-
bi.li.zi.ng systems, such as a mi.xture of a polyol with
bori.c aci.d or an alkali.metal borate; oxygen liberati.ng
bleaches, such as sodium perborate or percarbonate,
di.peri.sophthali.c anhydride wi.th or wi.thout bleach pre-
cursors, such as tetraacetyl ethylene diami.ne; or
chlori.ne li.berati.ng bleaches, such as di.chlorocyanu-
rate; anti.-oxi.dants, such as sodium sulphi.tes; opaci.-
fi.ers; fabri.c so~teni.ng agents; stabi.lizers, such aspolysacchari.de hydrocolloids, e.g. parti.ally acetylated
xanthan gum, commerci.ally available as "Kelzan" (ex
Kelco Comp., New Jersey, USA); buffers and the like.
The i.nventi.on is further i.llustrated by the following
Examples, i.n whi.ch parts and percentages are by
wei.ght, unless i.ndi.cated otherwi.se.
Example I
The followi.ng composi.ti.on was prepared:
Ingredient: %
-
Sodium dodecyl benzene sulphonate5.0
C13-C15 linear pri.mary alcohol, con-
densed wi.th 7 moles of alkylene oxi.de
(a mixture o~ ethylene- and propylene-
oxide in a weight rati.o of 92:~)2.0
Anhydrous sodi.um tripolyphosphate 21.0
Amorphous si.li.ca (elem. parti.cle size
10 nm, surface area 700 m2/g) 3.0
Sodium carboxymethylcellulose 0.2
Foam depressant 0.3
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~xample I, Ingredi.ents (continued)
%
Opti.cal hrightener 0.1
Stabi.lizer 0.2
Proteolyt;.c enzyme *
Enzyme stabilizer 10.0
Perfume 0.25
Water balance
pH 8.0
* The enzyme was added i.n such an amount that the
fi.nal product had a proteolyti.c activity of 9 GU/mg
(733 GU/mg = 1 Anson uni.t/g).
To demonstrate the corrosion inhibi.ting action of the
compositi.ons of the present i.nventi.on the aforemen-
ti.oned composi.ti.on was tested comparatively under
various temperature condi.tions and degrees of water
hardness.
Al-corrosion test
In order to assess the corrosive acti.on of a test wash
li.quor, circular plates of pure alumi.nium (~9.5% Al)
having a surface area of 40 cm2 were cleaned to re-
move surface grime and contami.nants. They were rinsedwith distilled water, dipped in methanol and air-
dried. After being wei.ghed the plates were subjected
to the test liquor for a period of 8 hours, during
whi.ch time the solution was stirred continuously. Sub-
sequently the plates were cleaned, dried and weighed.The corrosive action of the test liquor was expressed
in weight loss of aluminium per m2 and per hour. In
all tests the liquid detergent composition was dosed
to the wash liquor at a concentrati.on of 10 grams/-
li.tre, unless stated otherwise.
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Corrosion versus waterhardness test
By means of the corrosion test described above the
composi.ti.on of Example I was compared wi.th a control
composi.tion (i.e. the example compositi.on without the
si.li.ca) at various degrees of water hardness at a tem-
perature of 85~C. The hardness of the water i.s expres-
sed in degrees of French hardness (one degree French
hardness is equi.valent to 10 mg CaC03 per li.tre).
The followi.ng results were obtai.ned:
FH(Ca:~g = 3:1)Wei.ght loss of alumini.um
(g/m2/h)
_Comp.of Example I Control
0 1 4.0
12.5 1 2.4
c 0.1 1.1
37.5 1 0.4
c 0.1
Corrosion versus temperature test
By means of the corrosion test described above the
composi.ti.on of Example I was compared wi.th the control
composi.ti.on at various temperatures usi.ng deminerali~
zed water for the wash li.quor.
The following results were obtained:
Temperature (C)Weight loss of aluminium
(g/m2/h)
Comp.of Example I Control
1 0.4
1 0.8
~ 0.1 1.2
1 1.8
1 2.8
1 4.0
These results clearly show the corrosion inhibi.ti.ng
ef~ect of the silica.
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Example II
The following compositi.on was prepared:
Ingredi.ent: %
Sodium dodecyl benzene sulphonate 7.0
C13-Cl5 lin. prim. alcohol, con-
densed with 7 moles of alkylene oxi.de
ta mixture of ethylene oxide and propyl-
ene oxide i.n a wei.ght ratio of 92:8) 2.0
Coconut potassium soap 1.0
Sodium tripolyphosphate 23.8
Amorphous silica (elem. parti.cle size
10 nm, surf.area 700 m2/g) 2.0
Enzyme stabi.lizer 7.0
Proteolyti.c enzyme 9 GU/mg
Sodi.um carboxymethylcellulose 0.1
Opti.cal brightener 0.1
Foam depressant 0.2
Perfume 0.3
Water balance
pH 7.8
To illustrate the corrosive acti.on as a functi.on of
product dosage (and accordingly as a function of sili
ca concentrati.on) the composi.tion of Example II was
submitted to the corrosion test and compared with a
control compositi.on at different product dosages at a
temperature of 85C, usi.ng demineralized water for the
wash liquor.
The following results were obtai.ned:
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Product dosage Si.lica Weight loss of aluminium
(g/l) (ppm)(in g/m2/h)
Com~. of Ex. II Control
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10 200 G~ 0.1 4.0
9180 c 0.1 4.0
8 160 c 0.1 3.9
7 140 0.5 3.8
6 120 0.8 3.8
These results clearly i.ndicate that effective corro-
si.on i.nhi.biti.on is provided if the product dosage is
above 6 g/l, whi.ch corresponds to 120 ppm by wei.ght of
silica.
E~ample III
The following composi.tion was prepared:
Ingredi.ent %
Sodi.um dodecylbenzene sulphonate 8.0
Sodi.um laurylethersulphate 0.5
C12 li.n.-prim. alcohol condensed
wi.th 8 moles of ethylene oxide 2.5
Sodium pyrophosphate 11.0
Amorphous sili.ca (elem. part. 10 nm,
25 surface area 700 m2/g) 7.5
Enzyme stabili.zer 10.0
Proteolytic enzyme 9 GU/mg
Opti.cal brightener 0.2
Water balance
pH 8~0
The above composition was submitted to an experiment
equivalent to the one carried out in Example II. As
the above product should be used at a much lower
dosage, the investigated range of product dosages is
di.fferent.
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The following results were obtained:
Product dosage Silica Wei.ght loss of al~inium
(g/l) (ppm~ (in g/m2/h)
Comp. of Ex. III Control
3.0 225~c 0.1 1.7
2.5 188c 0.1 1.5
2.0 1500.4 1.3
1.5 1130.7 1~1
The above test shows that at least 120 ppm and preer-
ably 150 ppm of sili.ca should be present i.n the wash
li.quor in order to provide effecti.ve corrosion inhi.b-
ition.
Example IV
To illustrate the anti-corrosive acti.on of vari.ous
types of si.lica the corrosion test was performed on a
set of composi.tion prepared accordi.ng to the formula-
ti.on of Example 2 but di.fferi.ng therefrom in the type
of sili.ca employed. The amounts of sili.ca incorporated
equaled 10% by wei.ght of the composition.
The following results were obtai.ned at 85~C, zero
water hardness and 10 g/litre in-wash product dosage.
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12
Silica Type Elem.part. Surface Weight loss
size area of
(nm) (m2/g) aluminium
- -- - ~ (g/m2/h)
control - - - 4.0
Durosil 1) precipitated 25 50 3.1
'i~
Neosyl ET
2) precipitated 30 250 0.1
Tixosil
1038A 3) hydrogel 20 250 0.0
Gasil WP
2) hydrogel 1.5-2.0 850 0.0
Cab-O-Sil
M5 4) pyrogenic 14 200 0.0
15 Aerosil
380 1) pyrogenic 7 380 0.0
Gasil 35
2) xerogel 3-5 300 0.0
Gasil 200
202) xerogel 1.5-2.0 700 0.0
1) ex Degussa, Germany 4) ex Cabot Corp.Ill.,USA
2) ex Crosfield, UK
3) ex SI France
Example V
The composition according to example II was tested on
its effectiveness in protecting enamel from corrosion
30 attack.
The silica as specified in example II was included in
an amount of 2.596 by weight. This composition at an
in-wash dosage of 12 g/litre, zero waterhardness and
35 90C, was subjected to an enamel adapted corrosion
test similar to the above described A1-corrosion test.
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As enamel corrosion is a somewhat slower process than
metal corrosion, enamel covered steel plates were used
having a surface area of 100 cm2 and the testing
time was extended to a period of 24 hours.
Results indicate a significant anti-corrosive action:
Weight loss of enarnel
mg/dm2/24 hours
for the control composition 101
for the sample composition 19
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