Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
1999-12-13
2001-07-03
Gupta, Yogendra (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S119000, C510S121000, C510S122000, C510S123000, C510S127000, C510S130000, C510S135000, C510S151000, C510S152000, C510S153000, C510S155000, C510S156000, C510S242000, C510S417000, C510S434000, C510S437000, C510S466000, C510S490000
Reexamination Certificate
active
06255264
ABSTRACT:
The present invention relates to detergent compositions suitable for topical application for cleansing and improving the condition of the human body, particularly for moisturising the skin, hair, nails and other epithelial tissues, including the mucosae. In particular, it relates to compositions which are formulated to give mild cleansing and conditioning of the skin, and improved deposition of benefit agents.
Compositions formulated to cleanse the skin are well known. It is also known to formulate products which provide both a cleansing and a moisturising benefit.
For example WO 90/13283 discloses a composition comprising an acyl ester of an isethionic acid salt, a long chain fatty acid, a moisturiser component and, optionally, soap.
One of the problems which may be encountered with such dual purpose compositions is that they contain either an insufficient level of moisturiser component, or that an insufficient amount is deposited on use. In particular in the context of the second problem, insufficient deposition means that a large proportion of the benefit agent which is in the composition is wasted.
We have found a way of formulating such compositions such that they can deliver effective moisturising, conditioning and/or protection of the skin, and also a way of delivering benefit agents in a more efficient manner.
Thus, according to a first aspect of the invention, there is provided an aqueous liquid cleansing and moisturising composition comprising:
a) a surface active agent selected from anionic, nonionic, zwitterionic and cationic, surface active agents, soap and mixtures thereof;
b) a benefit agent; and
c) a cationic polymer
characterised in that the cationic polymer is present at levels of 0.05-3% by weight, and that the benefit agent is present in the neat composition as aggregated particles.
Compositions according to the invention are preferably shear thinning.
An advantage of compositions according to the present invention is that they lead to improved deposition of benefit agents from a surfactant containing aqueous liquid composition during use.
We have surprisingly found in compositions according to the invention that particles of the skin benefit agent form aggregates which comprise a number of individual particles. Aggregates which characterise compositions according to the invention may typically comprise 5-5000 individual particles of benefit agent. Without wishing to be bound by theory, it is suspected that compositions which comprise these aggregated particles, which aggregated particles stay in this form and do not coalesce, serve to deliver to the substrate relatively large aggregates of benefit agent, which provides an effective local high concentration of the benefit agent, thus enhancing the moisturising benefit to the substrate, and also the overall efficiency of delivery of the benefit agent.
As such, compositions according to the invention may typically comprise relatively high populations of relatively large, aggregated particles. Compositions according to the invention may therefore for example have a mean individual particle size of less than 5 microns, typically less than 1 micron, but contain about 50% or less by weight of the benefit agent in the composition in particles less 3 microns in size. Typically the composition may also comprise less than 10% by weight of the benefit agent in aggregated particles of greater than 80 microns in size. Compositions according to the invention typically have more than 3% by weight of the benefit agent in aggregated particles with sizes in the range 3-80 microns.
Compositions according to the invention also characteristically retain the aggregated microstructure during dilution in use, for example when diluted by a factor of 10 with distilled water. As such, compositions which have been diluted at ratios between 1:1 and 1:100 with water have been found also to retain the microstructure.
Compositions according to the invention, in particular containing the aggregated particles described, preferably contain not only relatively high levels of benefit agent, cationic polymer, and contain aggregated particles of benefit agent, but may conveniently also be made according to preferred process aspects. In the preferred process, it is important that the relatively high level of cationic polymer is sufficiently dispersed in the aqueous vehicle of the invention such that the product will have a smooth (i.e. not textured or lumpy) appearance. This can be quite difficult with the relatively high levels of cationic polymer in the composition, but is nevertheless within the remit of the skilled person to achieve.
The following also represent preferred aspects of the process of manufacture of compositions according to the invention:
a) The skin benefit agent should be prepared as a pre-emulsion, which is heated to 50-70° C.
b) The surfactant components of the composition are prepared as a solution, and the skin benefit agent pre-emulsions from a) are blended into the surfactant solution.
c) The cationic polymers are pre-dispersed in water in a controlled manner such that the rate of hydration of the cationic polymer is controlled if necessary. This can for example be done by dispersing the dried cationic polymer in a solution of pH at least 10, preferably greater than 11, to control hydration of the polymer, before dispersing it in the other components of the composition. Incomplete distribution of the cationic polymer is typified by a grainy appearance of the composition, or the presence of globules of undissolved polymer. Alternatively, the cationic polymer can be dispersed in a non-aqueous liquid component of the composition, such as eg glycerol. However, in such a situation the non-aqueous component must be present in the composition at sufficient and suitable levels so as to provide satisfactory, non-lumpy dispersion of the cationic polymer which will disperse satisfactorily in the aqueous vehicle. In any event, it is highly preferable that the cationic polymer is fully dispersed in the aqueous vehicle prior to it being fully hydrated.
d) Following the sequence of steps a)-c) above, the remaining components of the composition, with the exception of the perfume and preservatives, are blended together and maintained at or around 50-70° C. Complete mixing is preferably attained by subjecting the composition to high shear at this stage, but in such a manner that aeration of the composition is avoided; the high shear stage can typically take 20 minutes.
e) Following the sequence of steps a)-d), the composition is cooled to 30° C. where the minors (eg perfume, preservative) are added, and the viscosity is modified by the addition of the appropriate viscosity modifying agent.
In any event, it is preferred that the cationic polymer used in compositions according to the invention is at least partially hydrated when it is dispersed in the aqueous vehicle. If the cationic polymer is insufficiently hydrated, this may lead to insufficient aggregation of the droplets of benefit agent in the composition, whilst if the cationic polymer is overly hydrated, in particular during its dispersion in the composition, it may prove difficult to disperse satisfactorily.
The composition according to the invention is suitable for cleansing and “moisturising”, “conditioning” or “protection” of the skin. The benefit agent is included in the composition to moisturise, condition and/or protect the skin. By “benefit agent” is meant a substance that softens the skin (stratum corneum) and keeps it soft by retarding the decrease of its water content and/or protects the skin.
Preferred benefit agents, which may be solid or liquid at room temperature, but for the sake of simplicity of terminology herein are referred to as “particles”, include:
a) silicone oils, gums and modifications thereof such as linear and cyclic polydimethylsiloxanes, amino, alkyl alkylaryl and aryl silicone oils;
b) fats and oils including natural fats and oils such as jojoba, soyabean, rice bran, avocado, almond, olive, sesame, persic, castor, coconut, mink oils; cacao fat, beef t
Fleurot Olivier
Lee Robert Stanley
Boyer Charles
Gupta Yogendra
Koatz Ronald A.
Unilever Home & Personal Care USA , division of Conopco, Inc.
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