Liquid detergent composition containing stabilizing electrolyte mixtures

The invention pertains to aqueous liquid detergent compositions of the suspending type which comprise a nonionic detergent active material and/or derivative thereof in admixture with an anionic detergent active material and/or cationic detergent active material, and electrolytes which consist of one or more salting-out electrolytes and one or more auxiliary electrolytes having a lyotropic number of 9.5 or above, the combination of said salting-out and auxiliary electrolytes giving improved stability.

The present invention relates to an aqueous liquid detergent composition of 
the suspending type, i.e. a composition in which particles of a different 
density can be suspended. 
More particularly the invention relates to an aqueous liquid detergent 
composition of the suspending type, said composition comprising a nonionic 
detergent active material and/or a derivative thereof in admixture with an 
anionic detergent active material and/or a cationic detergent active 
material, said composition comprising electrolytes. 
Such compositions are known in the art, and a typical example of such a 
composition is an aqueous built liquid detergent composition comprising 
one or more builder salts. It is well known that the formulation and 
manufacture of such aqueous built liquid detergent compositions of the 
suspending type require measures to arrive at a satisfactorily stable 
(=non phase separating) product; such special measures are for example a 
critical balancing of the various ingredients, the use of special 
stabilizers, the use of special processing steps and the like. Analogous 
phase separation problems can occur with electrolytes other than builder 
salts, such as buffer salts, fillers and the like. 
During the investigation of aqueous liquid detergent compositions of the 
suspending type, comprising a mixture of an anionic and a nonionic 
detergent active material, as well as electrolytes, we have noticed that, 
when instability problems occurred, this was frequently accompanied by a 
lowering of the cloud point of the nonionic detergent active material 
caused by the electrolytes present. These electrolytes, at the levels 
used, cause a salting-out effect on the nonionic detergent active 
material. 
We have now found that the instability problems of such liquid compositions 
can be significantly reduced by inclusion in such compositions of an 
inorganic auxiliary electrolyte, the corresponding sodium salt having a 
lyotropic number of 9.5 and above (as determined by the method of Bruins, 
Proc. Acad. Amsterdam, 35, 107 (1932) on agar-agar and gelatin). By the 
use of such an auxiliary electrolyte, the instability of a liquid 
composition comprising a nonionic detergent active material and/or a 
derivative thereof, in admixture with an anionic detergent active material 
and/or a cationic detergent active material and a salting-out electrolyte, 
can be significantly reduced. There is no definite upper value of the 
lyotropic number; this value is primarily governed by practical 
considerations, such as type of electrolyte desired in the composition, 
especially type of the anion, etc. Usually the upper value will be about 
14, preferably 13.3. 
Accordingly, the present invention therefore relates to an aqueous liquid 
detergent composition of the suspending type, said composition comprising 
a nonionic detergent active material and/or a derivative thereof in 
admixture with an anionic detergent active material and/or a cationic 
detergent active material, and electrolytes, the electrolytes consisting 
of a mixture of one or more electrolytes having a salting-out effect on 
the nonionic detergent active material or a derivative thereof, and one or 
more auxiliary electrolytes, the latter having a lyotropic number as 
hereinbefore defined. The invention will be discussed below in more 
detail. 
It is well known that the extent to which a nonionic detergent active or 
derivative thereof is salted out by a salting-out electrolyte, resulting 
in a certain lowering of the cloud point, is dependent upon the nature and 
the amount of salting-out electrolyte used. In general the composition may 
contain from 1 to 60% by weight, and preferably from 3 to 50% by weight, 
and particularly preferably from 5 to 30% by weight of the salting-out 
electrolytes. 
Typical examples of such salting-out electrolytes are water-soluble builder 
salts, such as the alkali metal ortho- and pyrophosphates, the alkali 
metal tripolyphosphates, such as sodium tripolyphosphate, the alkali metal 
silicates, -borates, -carbonates, -sulphates, alkali metal citrates; 
alkali metal salts of nitrilotriacetate; alkali metal salts of 
carboxymethyloxy succinate. Instead of the alkali metal salts, the 
ammonium salts can be used. 
The invention is particularly applicable to compositions which contain 
sodium tripolyphosphate and/or sodium (di)silicate as the salting-out 
electrolyte. 
Depending upon type and level of salting-out electrolyte used, a certain 
level and/or type of auxiliary electrolyte is required. This can be 
determined by routine experimentation, using the general indications below 
as to level and type of auxiliary electrolytes, as also further 
exemplified in the Examples. 
Typical examples of suitable auxiliary electrolytes are alkali metal 
iodides, alkali metal (per)chlorates, alkali metal rhodanides, and alkali 
metal nitrates, and alkali metal bromides and -chlorides. The 
corresponding ammonium salts can also be used. The auxiliary electrolyte 
is generally used in the composition in an amount of 0.5 to 35% by weight, 
preferably 1 to 30% by weight, and particularly preferably 2 to 25% by 
weight. 
The total level of electrolyte present in the composition can vary from 1.5 
to 70% by weight. 
The anionic, cationic and nonionic detergent active materials used in the 
present invention can be any suitable well-known material. The anionics 
comprise the well-known anionic detergents of the alkylaryl sulphonate 
type, the alkyl sulphate type, the alkane- and alkene sulphonate type and 
so on. Numerous other examples can be found in Schwartz, Perry, Vol. II, 
1958, "Detergents and Surface-Active Agents". 
The nonionics comprise ethylene oxide and/or propylene oxide condensation 
produces with alcohols, alkylphenols, fatty acids, fatty acid amides; the 
above-mentioned reference gives further examples of nonionics. Fatty acid 
mono- and dialkylol amides, as well as tertiary amine oxides are also 
included in the terminology of nonionic detergent active compounds. 
As derivatives of nonionic detergent active materials, those compounds are 
contemplated that are derived from nonionics, such as sulphated, 
phosphonated or carboxylated nonionics. 
Examples of cationic detergents are the quaternary ammonium compounds, such 
as di(higher alkyl)di(lower alkyl)ammonium halides. 
Although cationics can be used according to the present invention in 
combination with the nonionics, it is preferred to use anionics in 
combination with the nonionics. 
The ratio of anionic to nonionic may vary from 10:1 to 1:10, preferably 5:1 
to 1:1, and the total amount of active detergent material may vary from 2 
to 50, preferably from 5 to 35% by weight. 
The compositions of the invention may furthermore comprise all the other 
detergent ingredients usually encountered in such products, such as 
enzymes, fluorescers, soil-redeposition agents, germicides, opacifiers, 
suds boosters, foam depressants, corrosion inhibitors, perfumes, bleaching 
agents, bleach precursors, solvents, and so on. They are suitable for 
stably suspending particulate material, such as insoluble particulate 
material like zeolites, abrasive materials like calcite, and undissolved 
particulate builder salts. 
The compositions of the invention have an alkaline pH, normally in the 
range of 7 to 13.

The invention will be further illustrated by way of Example. 
EXAMPLE 1 
A stock solution was prepared comprising: 
16.9% by weight of dodecyl benzene sodium sulphonate 
3.9% C.sub.13 -C.sub.15 primary alcohol, condensed with 11 moles of 
ethylene oxide 
79.2% distilled water 
The anionic/nonionic ratio was 4.3 and the total active detergent content 
abt. 20%. 
To 100 g of this stock solution were added 16 g of a 32% aqueous solution 
of sodium disilicate (Na.sub.2 O:SiO 2.1) (composition A), 16 g of the 
same sodium disilicate solution plus 9 g of sodium iodide (lyotropic 
number 12.5) (composition B), and 16 g of the same sodium disilicate 
solution plus 18 g of sodium iodide (composition C). 
These compositions were stored at room temperature and assessed for their 
storage stability. (Stable=.ltoreq.1% phase separation; unstable 
.gtoreq.3% phase separation). 
Composition A was already unstable after less than 1 hour; compositions B 
and C were still stable after 6 months. 
Increasing the disilicate solution level in A, B and C to 32 g, and using 6 
and 9 NaI in B and C gave products which were unstable after 1 hour 
(A.sup.1), stable for 1 month (B.sup.1) and stable for more than 6 months 
(C.sup.1). 
Using a mixture of 16 g of disilicate solution and 4.2, 5.6, 8.2 or 16.8 g 
of sodium perchlorate (lyotropic number 11.6) in 100 g stock solutions 
gave products which were all stable for more than 3 months. 
EXAMPLE 2 
Using 5 g of trisodium carboxy methyloxy succinate 5H.sub.2 O ("CMOS") in 
100 g of the stock solution (composition D), 5 g of CMOS+11.2 g of sodium 
perchlorate (composition E) or 5 g of CMOS plus 22.4 g of sodium 
perchlorate in 100 g of the stock solution (composition F) gave the 
following results: 
D: unstable after 1 day 
E: stable for more than 3 months 
F: stable for more than 3 months 
EXAMPLE 3 
A stock was prepared comprising: 
16.9% by weight of dodecyl benzene sodium sulphonate 
3.9% C.sub.13 -C.sub.15 primary alcohol, condensed with 11 moles of 
ethylene oxide 
79.2% distilled water 
The anionic/nonionic ratio was 4.3 and the total active detergent content 
was abt. 20%. 
To 100 g of the stock solution were added 12.5 g of sodium tripolyphosphate 
and 6 g of sodium disilicate. This composition (G) was unstable within 3 
days. Addition of the auxiliary electrolytes to composition G gave the 
following results: 
______________________________________ 
Stability (days) 
Amount of auxiliary electrolyte added 
Auxiliary 
(moles) to 118.5 g of composition G 
electrolyte 
0.02 0.03 0.04 0.06 0.08 0.12 0.16 
______________________________________ 
Na I &gt;90 80 &gt;90 80 80 &gt;90 &gt;90 
NaBr &lt;3 3 10 50 90 50 50 
(Lyotropic 
number 11.3) 
NaNO.sub.3 
&lt;3 &lt;3 &gt;90 &gt;90 &gt;90 &lt;3 &lt;3 
(Lyotropic 
number 11.8) 
______________________________________ 
To 100 g of this stock solution were added 25 g of sodium tripolyphosphate 
and 7.5 g of sodium disilicate. This composition (H) was unstable within 3 
days. Addition of the auxiliary electrolytes to composition H gave the 
following results. 
______________________________________ 
Stability (days) 
Amount of auxiliary electrolyte added 
Auxiliary 
(moles) to 132.5 g of composition H 
electrolyte 
0.02 0.03 0.04 0.06 0.08 0.12 0.16 
______________________________________ 
NaI 20 70 &gt;90 55 85 60 &lt;3 
NaBr &lt;3 &lt;3 &lt;3 15 20 75 75 
NaNO.sub.3 
&lt;3 &lt;3 &lt;3 35 10 &lt;3 &lt;3 
______________________________________ 
EXAMPLE 4 
A stock solution was prepared comprising: 
14.7% by weight of dodecyl benzene sodium sulphonate 
5.9% C.sub.12 -C.sub.15 primary alcohol condensed with 7 moles of a mixture 
of ethylene- and propylene oxide containing 92% ethylene oxide 
79.4% distilled water. 
The anionic/nonionic ratio was 2.5 and the total active detergent content 
was abt. 20%. 
To 100 g of this stock solution were added 25 g of sodium tripolyphosphate 
and 7.5 g of sodium disilicate. This composition (K) was unstable within 3 
days. Addition of the auxiliary electrolytes to composition K gave the 
following results: 
______________________________________ 
Stability (days) 
Amount of auxiliary electrolyte added (moles) 
Auxiliary 
to 132.5 g of composition K 
electrolyte 
0.02 0.03 0.04 0.06 0.08 0.12 0.16 
______________________________________ 
NaI 15 &gt;90 &gt;90 60 60 60 60 
NaBr &lt;3 10 35 &gt;90 &gt;90 40 &gt;90 
NaNO.sub.3 
15 15 15 3 10 &gt;90 20 
______________________________________ 
EXAMPLE 5 
A stock solution was prepared comprising 
10.7% by weight of dodecyl benzene sodium sulphonate 
10% coconut diethanol amide 
79.3% water 
The anionic/nonionic ratio was 1.1 and the total active detergent content 
abt. 20% . 
To 100 g of this stock solution were added 8 g of sodium orthophosphate, 4 
g of sodium triphosphate and 10 g sodium disilicate. This composition (L) 
was unstable within 1 day. Addition of the auxiliary electrolyte to 
composition L gave the following results: 
______________________________________ 
Stability (days) 
Amount of auxiliary electrolyte added 
Auxiliary (moles) to 122 g of composition L 
electrolyte 
0.025 0.04 0.07 0.11 0.15 
______________________________________ 
NaCNS (lyo- 
&gt;65 &gt;65 35 15 7 
tropic number 
13.3) 
NaI &gt;90 &gt;90 35 20 20 
NaNO.sub.3 20 65 &gt;90 70 40 
NaClO.sub.3 
50 20 65 30 15 
(lyotropic 
number 10.6) 
NaCl &lt;1 &gt;90 40 10 3 
(lyotropic 
number 10.0) 
______________________________________