Cleaning compositions for solid surfaces – auxiliary compositions – Auxiliary compositions for cleaning – or processes of preparing – Textile softening or antistatic composition
Reexamination Certificate
2000-07-05
2002-08-13
Hardee, John (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Auxiliary compositions for cleaning, or processes of preparing
Textile softening or antistatic composition
C510S525000
Reexamination Certificate
active
06432911
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to fabric conditioning compositions, and in particular, relates to concentrated cationic fabric softener compositions in the form of water-in-oil micro-emulsions.
BACKGROUND OF THE INVENTION
Rinse added fabric conditioning compositions are well known. Typically, such compositions comprise a fabric softening agent dispersed in water. The fabric softening agent can be included at up to 8% by weight, in which case the compositions are considered dilute, or at levels from 8% to 60% by weight, in which case the compositions are considered concentrated.
In addition to softening, fabric conditioning compositions desirably have other properties, including stability upon storage, good dispersibility in water and delivery of sufficient amounts of perfume to the fabric being treated.
One of the problems frequently associated with conventional concentrated fabric conditioner compositions is physical instability upon storage. This problem is usually accentuated when the composition is stored at low temperature (e.g. at 5° C. or below) or at elevated temperatures.
Physical instability can manifest itself as a thickening of the composition. This thickening can occur to a level at which the composition is no longer pourable, and, can even lead to the formation of an irreversible gel. Such thickening is very undesirable because the composition can thereafter no longer be conveniently used and/or it is unattractive to the consumer.
However, fabric conditioning concentrates are increasingly desired by the consumer. The consumer requires these products to be stable upon storage.
EP 0 829 531 Al (Unilever) discloses a concentrated fabric conditioner composition, comprising a cationic softener suspended in oil, which delivers perfume benefits to the fabric being treated.
Concentrated, clear compositions containing fabric softening actives have been disclosed in WO 98/08924 and WO 98/47991 (both Procter & Gamble). Such compositions comprise bio-degradable fabric conditioners. However, both disclose compositions comprising water miscible solvents which do not form water-in-oil micro-emulsions.
Clear fabric conditioning compositions have also been disclosed in EP 730023 (Colgate Palmolive), WO 96/19552 (Colgate Palmolive), WO 97/47723 (Colgate Palmolive), WO 96/33800 (Witco Co.), WO 97/03170 (Procter & Gamble), WO 97/03172 (Procter & Gamble), WO 97/03169 (Procter & Gamble), U.S. Pat. No. 5,492,636 (Quest Int.) and U.S. Pat. No. 5,427,697 (Procter & Gamble).
A further problem associated with many conventional concentrated fabric conditioners is that the perfume intensity in the composition decreases significantly during storage. This, correspondingly, results in a less ‘perfumed’ effect being given to fabric treated with the composition.
However, perfume longevity during storage and perfume delivery are also highly valued by the consumer. Therefore, it is desirable to provide a fabric treatment composition which gives increased perfume longevity during storage, and, better perfume delivery in use.
OBJECTS OF THE INVENTION
Thus, the present invention seeks to address one or more of the above-mentioned problems, and, to give one or more of the above-mentioned benefits desired by consumers.
Surprisingly, we have found that a fabric conditioning composition in the form of a micro-emulsion has good physical stability upon storage, increased perfume longevity and improved perfume delivery to the fabric. In addition, providing the composition as a micro-emulsion appears to improve both dispersion of the composition in water and dispensing of the composition from a dispensing drawer of a washing machine.
SUMMARY OF THE INVENTION
According to the present invention there is provided an aqueous fabric conditioning composition comprising:
(i) one or more cationic surfactants selected from:
(a) quaternary ammonium compounds having at least one ester group and being formed from a parent fatty acid having a degree of unsaturation represented by an iodine value of from 20 to 140 and,
(b) quaternary ammonium compounds having two C
8
-C
28
alkyl or alkenyl chains directly attached to the nitrogen and being formed from a parent fatty acid having a degree of unsaturation represented by an iodine value of from 0 to 20 and,
(ii) one or more oils,
(iii) one or more solvents,
the composition being in the form of a micro-emulsion.
According to the invention, there is also provided a process for conditioning fabrics comprising the step of adding to a laundry operation the abovementioned fabric conditioning composition.
According to the invention, there is also provided a method for preparing an aqueous fabric conditioning composition comprising mixing a cationic surfactant, an oil, a solvent and water and either agitating or heating the mixture to form a micro-emulsion.
According to the invention, there is further provided a macro-emulsion formed by diluting the aforementioned fabric conditioning composition with water.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is particularly concerned with cationic fabric softening compositions which are in the form of water-in-oil micro-emulsions.
In the context of the present invention, the term ‘micro-emulsion’ means a liquid product which is clear or translucent, isotropic and thermodynamically stable over a specified temperature range. It does not include conventional macro-emulsions which are not clear and isotropic.
The compositions of the invention are typically thermodynamically stable above 10° C. Below 10° C. the compositions may become hazy but recover upon warming to ambient temperature where they revert back to a clear isotropic micro-emulsion. When diluted, the compositions are transformed to inverse macro-emulsions (including multiple emulsions) which typically have droplet sizes of 10 &mgr;m or less or mesophases.
Without wishing to be bound by theory, it is believed that the compositions of the invention have a physical state wherein water droplets are stabilised within an oil continuous phase by the cationic surfactant and, if present, a dispersibility aid. Typically, the water droplets in the emulsion have a diameter of between 50-500 Å. The physical structure can be bicontinuous in nature (for an explanation of the physical structures see Micelles, Membranes, Micro-emulsions and Mono-layers, Ed. Gelbart et. al., Springler-Verlag, Chapter 7).
Cationic Surfactant
The fabric conditioning composition of the present invention comprises one or more cationic surfactants.
These surfactants are fabric softening compounds which are typically included in rinse-added fabric softening compositions.
The surfactants may be quaternary ammonium compounds having at least one ester group and being formed from a parent fatty acid having a degree of unsaturation represented by an iodine value of from 20 to 140 (referred to as type (a) herein).
Alternatively, the cationic surfactants may comprise quaternary ammonium compounds having two C
8
-C
28
alkyl or alkenyl chains being directly attached to the nitrogen with the compound being formed from a parent fatty acid having a degree of unsaturation represented by an iodine value of from 0 to 20 (referred to as type (b) herein).
Preferably, the average chain length of the alkyl or alkenyl group is at least C
14
, more preferably at least C
16
. Most preferably at least half of the chains have a length of C
18
.
Mixtures of the aforementioned types of cationic surfactants, that is mixtures of either type (a) or (b), may also be used according to the invention.
It is generally preferred if the alkyl or alkenyl chains are predominantly linear.
It is especially preferred if the cationic surfactant is a water insoluble quaternary ammonium material which comprises a compound having two C
12-18
alkyl or alkenyl groups connected to the nitrogen head group via at least one ester link. It is more preferred if the quaternary ammonium material has two ester links present.
A first group of preferred ester-linked cationic surfactant materials for use in the invention is represented
Buron Helene Sylvie
Jones Craig Warren
Martinez-Escolano Pablo
Soubiran Laurent
Hardee John
Plotkin Ellen
Unilever Home & Personal Care USA , division of Conopco, Inc.
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