Composition for softening fabrics: clay softening agent and nonionic surfactant with 0.degree.-15.degree. C. cloudy phase

A particulate composition useful in the softening of fabrics from a wash liquor, especially in the form of a fabric washing product, comprises a fabric softening clay and a nonionic surfactant system which has a cloud point below 15.degree. C. The clay/nonionic weight ratio is from 2:3 to 20:1. A typical nonionic surfactant is a fatty alcohol with a low degree of ethoxylation, such as a C.sub.13-15 alcohol with 3 ethylene oxide groups per molecule.

BACKGROUND 
This invention relates to a composition for softening fabrics and in 
particular to such a composition which is particulate and capable of 
imparting a softening benefit to fabric during a wash process. 
A number of materials have been suggested in the art for providing 
softening-in-the-wash benefits. These include certain classes of clay 
materials, especially smectite clays. Thus GB 1400898 (Procter and Gamble) 
suggests the use of smectite clays having a relatively high exchange 
capacity. While some fabric softening benefit can be obtained from 
detergent compositions containing fabric softening clays, this benefit is 
generally some way short of that which can be obtained by the application 
of softening materials to fabrics in the rinse step of a laundering 
process. Therefore, there is a desire to boost the performance of fabric 
softening clays in the wash. GB 2138037 (Colgate) proposes that the 
performance of fabric softening clays can be improved by the removal of 
grit therefrom and by their addition to the detergent composition as 
separate agglomerated particles. 
Several disclosures in the art suggest that the performance of fabric 
softening clays is especially poor in the presence of nonionic 
surfactants. Thus, for example, GB1462484 (Procter & Gamble) proposes that 
in the presence of nonionic surfactants it is necessary to use smectite 
clays which have been rendered organophilic by an exchange reaction with 
quarternary ammonium compounds. GB 1400898, referred to above, is silent 
on the presence of nonionic surfactants. Also, European Patent 
Specification EP-11340-A (Procter & Gamble) teaches that, in a composition 
which includes a mixture of a smectite clay and a tertiary amine for 
softening-in-the-wash, when anionic surfactants are employed it is 
preferred that nonionic surfactants be absent, but if mixtures containing 
nonionics are used, it is preferred that the anionic forms the major part 
of the mixture. 
It is apparent therefore that a prejudice has built up against the use of 
nonionic surfactants in combination with clays for softening-in-the-wash, 
especially in the presence of anionic surfactants. 
DISCLOSURE OF THE INVENTION 
We have surprisingly found however that in the presence of certain nonionic 
surfactant materials, at a specified level relative to the clay, the 
fabric softening performance of clays can in fact be enhanced. 
The nonionic surfactant or mixture thereof which is essential to the 
present invention exists as a cloudy phase at 1% concentration in water at 
a temperature somewhere between 0.degree. C. and 15.degree. C. To obtain 
the benefits of the invention it is necessary that the weight ratio of the 
clay to this nonionic surfactant system is from 2:3 to 20:1, preferably 
from 1:1 to 10:1. Any other nonionic surfactant material present which 
does not exist as a cloudy phase between these specified temperatures is 
not counted for the purposes of calculating the required clay to nonionic 
ratio. 
The compositions of the invention may be in any particulate form, 
especially where the clay and the nonionic surfactant system are not in 
undiluted intimate contact with each other. More specifically however, 
this composition may be in the form of clay agglomerates which are formed 
of fine particle size clay, bound together with a material other than said 
nonionic surfactant system as a binder, or with no binder at all, the 
agglomerates carrying the nonionic surfactant system on the surface 
thereof. Alternatively, it is possible for the compositions of the 
invention to be in the form of spray-dried granules, formed, for example, 
by preparing an aqueous slurry containing the clay and the nonionic 
surfactant system and spray-drying the slurry to form the granules. A 
further alternative is to spray the nonionic surfactant system onto 
spray-dried base powder granules which may contain the clay or may have 
previously been mixed with the clay. Still further, the nonionic 
surfactant system may be carried on a suitable carrier material, the clay 
being separately added to the composition. 
All the above forms of the composition may contain other ingredients, 
especially ingredients useful in the washing of fabrics. Alternatively, 
such other ingredients may be added separately. In either case a fully 
formulated fabric washing product may be obtained, and it is preferred 
that overall such products contain at least from 2% to 50%, most 
preferably from 5% to 40% by weight of a detergent active material, which 
amount includes the nonionic surfactant system associated with the fabric 
softening clay; from 20% to 70%, most preferably from 25% to 50% by 
weight, of a detergency builder material and from 1.5% to 35%, most 
preferably from 4% to 15% by weight of fabric softening clay material 
having associated with it the nonionic surfactant system. 
THE NONIONIC SURFACTANT SYSTEM 
The nonionic surfactant system of the present invention exists as a cloudy 
phase somewhere in the temperature range of 0.degree. C. to 15.degree. C., 
preferably 0.degree. C. to 10.degree. C. in distilled water at 1% 
concentration. In practise this means that the system has a cloud point of 
not more than 15.degree. C., preferably not more than 10.degree. C. Cloud 
point is a term well known in the art, for example from Surface Active 
Ethylene Oxide Adducts by N. Schonfeldt, Pergamon Press 1969, pp 145 to 
154. In general terms the cloud point of a surfactant material is the 
temperature at which association between the surfactant and water 
molecules through hydrogen bonding breaks down, leading to the separation 
of surfactant rich and water rich phases and a consequential increase in 
turbidity or cloudiness. 
The cloud point correlates approximately to the hydrophilic-lipophilic 
balance (HLB) of the surfactant system and it is therefore preferred that 
the HLB should be less than 9.5, such as not more than 9.2. The HLB should 
preferably be above 6.0, most preferably above 8.0 to provide sufficient 
detergency. 
Suitable nonionic detergent compounds which may be used include in 
particular 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 (C.sub.6 -C.sub.22) phenols-ethylene oxide 
condensates, the condensation products of aliphatic (C.sub.8 -C.sub.18) 
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. Other so-called nonionic detergent 
compounds include long chain tertiary amine oxides, long chain tertiary 
phosphine oxides and dialkyl sulphoxides. 
Where, for example, alkylene oxide adducts of fatty materials are used as 
the nonionic detergent compounds, the number of alkylene oxide groups per 
molecule has a considerable effect upon the cloud point as indicated by 
the Schonfeldt reference mentioned above. 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 for example that where the 
fatty material is a fatty alcohol having about 13 to 15 carbon atoms, the 
adduct having 3 ethylene oxide groups per molecule has a cloud point of 
less than 0.degree. C. and is therefore suitable for use in the present 
invention. A similar surfactant having 7 ethylene oxide groups per 
molecule has a cloud point of about 48.degree. C. and is therefore 
unsuitable. Further ethoxylation raises the cloud point still higher. Thus 
the similar surfactant with 11 ethylene oxide groups per molecule has a 
cloud point higher than 80.degree. C. 
Where mixtures of surfactant materials are used, it is the properties of 
the individual components of the mixture rather than their average 
properties which are important. 
Thus, whilst a 1:1 mixture of such 3EO and 11EO ethoxylated alcohols may 
well have an HLB close to that of the 7EO material, the 7EO material alone 
would give a clear solution below 15.degree. C., passing to a cloudy 
condition above about 48.degree. C., while the mixture would be cloudy 
below 15.degree. C. In the context of the present invention therefore, the 
use of the 7EO material would be unsuitable while the mixture of 3EO and 
11EO materials would be suitable. However, when a mixture of nonionic 
surfactants is present for the purposes of determining the suitable clay 
to nonionic ratio only those nonionic materials which exist in the cloudy 
phase are counted. With some mixtures of nonionic surfactants, especially 
mixtures of surfactants which do not have closely related structures, some 
separation may occur so that some components of the mixture form the 
cloudy phase while others, generally the more soluble components, exist 
only in the clear phase. Analysis of the cloudy phase, using methods well 
known in the art, can determine the content of the cloudy phase in these 
circumstances. 
THE CLAY MATERIAL 
The clay containing material may be any such material capable of providing 
a fabric softening benefit. Usually these materials will be of natural 
origin containing a three-layer swellable smectite clay which is ideally 
of the calcium and/or sodium montmorillonite type. It is preferable to 
exchange the natural calcium clays to the sodium form by using sodium 
carbonate, as described in GB 2 138 037 (Colgate). The effectiveness of a 
clay containing material as a fabric softener will depend inter alia on 
the level of smectite clay. Impurities such as calcite, feldspar and 
silica will often be present. Relatively impure clays can be used provided 
that such impurities are tolerable in the composition. In calculating the 
suitable clay to nonionic ratios however, it is the amount of smectite 
clay present which is important. 
OPTIONAL COMPONENTS 
When the compositions of the invention, or the fabric washing products 
containing them, contain a detergent active material in addition to the 
nonionic surfactant system referred to above, this may be selected from 
other nonionic detergent active materials, anionic detergent active 
materials, zwitterionic or amphoteric detergent active materials or 
mixtures thereof. 
The anionic detergent active materials are usually water-soluble alkali 
metal salts of organic sulphates and sulphonates having alkyl radicals 
containing 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 sulphates, especially those obtained by sulphating higher (C.sub.8 
-C.sub.18) alcohols produced for example from tallow or coconut oil, 
sodium and potassium alkyl (C.sub.9 -C.sub.20) benzene sulphonates, 
particularly sodium linear secondary alkyl (C.sub.10 -C.sub.15) 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 (C.sub.8 -C.sub.18) fatty alcohol-alkylene 
oxide, particularly 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 (C.sub.8 
-C.sub.20) with sodium bisulphite and those derived from reacting 
paraffins with S0.sub.2 and C1.sub.2 and then hydrolysing with a base to 
produce a random sulphonate; and olefin sulphonates, which term is used to 
describe the material made by reacting olefins, particularly C.sub.10 
-C.sub.20 alpha-olefins, with S0.sub.3 and then neutralising and 
hydrolysing the reaction product. The preferred anionic detergent 
compounds are sodium (C.sub.11 -C.sub.15) alkyl benzene sulphonates and 
sodium (C.sub.16 -C.sub.18) alkyl sulphates. 
When the compositions of the invention, or the fabric washing products 
containing them, 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 composition with other beneficial 
properties such as the generation of an alkaline pH, the suspension of 
soil removed from the fabric and the dispersion of the fabric softening 
clay material. 
Examples of phosphorus-containing inorganic detergency builders, when 
present, include the water-soluble salts, especially alkaline metal 
pyrophosphates, orthophosphates, polyphosphates and phosphonates. Specific 
examples of inorganic phosphate builders include sodium and potassium 
tripolyphosphates, phosphates and hexametaphosphates. 
Examples of non-phosphorus-containing inorganic detergency builders, when 
present, include water-soluble alkali metal carbonates, bicarbonates, 
silicates and crystalline and amorphous alumino silicates. Specific 
examples include sodium carbonate (with or without calcite seeds), 
potassium carbonate, sodium and potassium bicarbonates and silicates. 
Examples of organic detergency builders, when present, include the alkaline 
metal, ammonium and substituted ammonium polyacetates, carboxylates, 
polycarboxylates, polyacetyl carboxylates and polyhydroxsulphonates. 
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. 
Apart from the ingredients already mentioned, a number of optional 
ingredients may also be present, either as part of the clay containing 
compositions or as part of the overall fabric washing product. 
Examples of other ingredients which may be present in the composition 
include the lather boosters, lather depressants, oxygen-releasing 
bleaching agents such as sodium perborate and sodium percarbonate, peracid 
bleach precursors, chlorine-releasing bleaching agents such as 
tricloroisocyanuric acid, inorganic salts such as sodium sulphate, and, 
usually present in very minor amounts, fluorescent agents, perfumes, 
enzymes such as proteases and amylases, germicides and colourants.

EXAMPLES 
The invention will now be illustrated by the following non-limiting 
examples. 
EXAMPLES 1 and 2 
Detergent compositions were prepared by spray-drying some ingredients to 
form a spray-dried base powder and then post-dosing the remaining 
ingredients. The approximate formulations were as follows: 
______________________________________ 
Example No: 
Ingredients (% by weight) 
1 2* 
______________________________________ 
Spray-dried: 
Anionic detergent active 
9.0 9.0 
Nonionic Active A7.sup.1 
1.0 1.0 
Sodium tripolyphosphate 
21.5 21.5 
Sodium alkaline silicate 
5.5 5.5 
Polymer.sup.2 2.7 2.7 
Water and minor ingredients 
10.3 10.3 
Post-dosed 
Sodium perborate monohydrate 
5.0 5.0 
Silicone antifoam granule 
1.2 1.2 
TAED 4.6 4.6 
Dequest 0.2 0.2 
Sodium carbonate 5.0 5.0 
Burkeite/A3.sup.3 12.0 -- 
Burkeite/A7.sup.4 -- 12.0 
Clay.sup.5 10.0 10.0 
Sodium sulphate balance balance 
*comparative example 
______________________________________ 
NOTES 
.sup.1 Synperonic A7 (ex ICI) which is a C.sub.13 -C.sub.15 alcohol 
ethoxylated with approximately 7 moles of ethylene oxide per molecule and 
having a cloud point 48.degree. C. 
.sup.2 DKW 125N (ex National Starch) which is a phosphinated polyacrylate 
antiredeposition polymer. 
.sup.3 Synperonic A3 (as A7 but containing an average of three moles 
ethylene oxide per molecule) 1 part carried on 3 parts Burkeite. 
Synperonic A3 has a cloud point of less than 0.degree. C. 
.sup.4 As 3, but using A7 in place of A3. 
.sup.5 ASB1.7 (ex English China Clay) in the form of granulated calcium 
montmorillonite from Morocco (94% montmorillonite). 
It will be seen that the nonionic surfactant system in Example 1 consists 
of 1% A7 plus 3% A3 while the nonionic surfactant system in comparative 
Example 2 consists of 4% A7. 
In order to compare the softening-in-the-wash performance of these two 
formulations, they were used to wash fabrics under the following 
conditions: 
______________________________________ 
Dosage 6 g/l 
Water hardness 24.degree. FH 
Wash temperature 40.degree. C. or 60.degree. C. 
Fabrics Preharshened terry towelling 
Wash time 30 minutes 
Rinse 3 .times. 5 minutes 
______________________________________ 
After line drying, the treated fabrics were judged for softness by a panel 
of experienced assessors who together assign a softening score for each 
tested formulation. 
The results were as follows, with softening being expressed as a percentage 
of the maximum possible preferance score: 
______________________________________ 
Example No. 
Softness at 40.degree. C. 
Softness Score 60.degree. C. 
______________________________________ 
1 69% 82% 
2 31% 16% 
______________________________________ 
A 20% difference in softness is significant. These results demonstrate the 
softening benefit obtained in the case of the composition according to the 
invention is preferred, at both 40.degree. C. and 60.degree. C., to that 
obtained with a similar composition not containing the low cloud point 
nonionic surfactant system. 
EXAMPLES 3 and 4 
Detergent compositions were prepared by post-dosing the following 
ingredients to the same base powder as used in Example 1: 
______________________________________ 
Example No: 3 4* 
______________________________________ 
Ingredients (parts by weight) 
Base powder 50.0 50.0 
Sodium carbonate 5.0 5.0 
Burkeite/A3 12.0 -- 
Burkeite/A7 -- 12.0 
Clay 20.0 20.0 
______________________________________ 
*comparative example 
These formulations were evaluated in the same manner as described in 
Examples 1 and 2 with the following results: 
______________________________________ 
Example No. Softness at 40.degree. C. 
______________________________________ 
3 81% 
4 14% 
______________________________________ 
A significant benefit is shown for the use of a nonionic surfactant system 
with the lower cloud point. 
Similar results are obtained when the granulated calcium montmorillonite is 
replaced with the sodium equivalent or with Detecol, which is an impure 
calcium montmorillonite clay (40% montmorillonite) in granular form (ex 
Carlo Laviosa, Italy). 
EXAMPLES 5 to 13 
Compositions were prepared by spray-drying the following ingredients, the 
nature of which was the same as in Examples 1 and 2. 
______________________________________ 
Ingredients (parts by weight) 
______________________________________ 
Anionic detergent active 
9.0 
Nonionic active A7 1.0 
Sodium tripolyphosphate 
21.5 
Sodium alkaline silicate 
5.5 
Polymer 2.7 
Water 10.3 
______________________________________ 
To this spray-dried base was added 10 parts of Prassa clay (ex Colin 
Stewart Minerals--96% montmorillonite) and a variable amount of nonionic 
active A3, as set out below. 
In order to compare the softening-in-the-wash performance of these 
formulations, they were used to wash fabrics under the following 
conditions: 
______________________________________ 
Dosage Equivalent to 0.5 g/l clay 
Water hardness 24.degree. FH 
Wash temperature 40.degree. C. 
Fabrics Preharshened terry towelling 
Wash time 15 minutes 
Rinse 2 .times. 2 minutes 
______________________________________ 
Softness assessment was carried out as described in connection with Example 
1, each composition being compared with that of Example 5, which contained 
no A3. 
The results were as follows: 
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% Preference 
Example No % A3 against control 
______________________________________ 
5* -- Control 
6* 0.4 44% 
7 0.67 58% 
8 1.0 67% 
9 3.0 71% 
10 5.0 71% 
11 10.0 71% 
12 15.0 67% 
13* 20.0 49% 
______________________________________ 
In all of these examples (except Example 5) A3 will exist as a cloudy phase 
below 15.degree. C. These results show that softening performance 
initially improves as the level of low cloud point nonionic active is 
increased, reaching an optimum level with about 3% A3. Thereafter, the 
addition of further A3 produces no improvement, leading eventually to a 
loss of performance.