Wet-skin treatment compositions

Details Wet-skin treatment compositions Wet-skin treatment compositions

2003-04-29

2004-04-06

Webman, Edward J. (Department: 1617)

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Cosmetic, antiperspirant, dentifrice

C514S938000, C514S844000, C514S847000

Reexamination Certificate

active

06716440

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to wet-skin treatment compositions that are designed for use during bathing to impart desirable properties to the skin, help maintain its health and protect it from environmental stress. By using aqueous dispersions of specific structured oil phases, which satisfy specific criteria in tests defined herein, applicants have obtained compositions that are activated by water and retained efficiently on skin. More particularly, at least a portion of the structured oil phase comprises a dispersed phase which may in turn comprise inorganic particles, organic particles or droplets of water soluble ingredients.
These wet skin treatment compositions impart the noted desirable benefits to the skin and are perceived to absorb quickly on wet skin, thereby leaving the skin feeling clean and non-greasy after rinsing. Thus, the consumer obtains the benefit of oily benefit agent from the wash, but does not perceive “greasy” feeling often associated with the benefit agent even after rinsing.
BACKGROUND OF INVENTION
Compositions that can effectively moisturize and protect the skin during the bathing process while the skin is still wet are a potentially convenient, and time saving approach to skin treatment. By bathing is meant any number of processes commonly used to cleanse the body and face, e.g., showering. To be truly effective, these compositions must be such that an adequate level of benefit agent is retained on the skin after rinsing and/or towel drying without at the same time imparting an excessively oily feel to the wet and dry skin and without leaving it looking too shiny.
Bath oil, which is used by some consumers, must be applied sparingly because it does not absorb efficiently on the skin and the excess can be very oily and messy. Furthermore light bath oils (i.e., oils that have a low viscosity and spread on the skin) absorb more rapidly to overcome this problem, but are not very effective in providing longer lasting benefits.
Conventional oil-in-water emulsion type skin lotions or creams that are designed to be applied to dry skin, even water resistant variants, are very poorly retained when applied to wet skin that is either further rinsed or towel dried. By contrast, conventional water-in-oil skin lotions that are designed for application to dry skin are very efficiently retained on wet skin but are excessively greasy and messy and are not perceived to absorb quickly.
U.S. Pat. No. 5,578,299 to Starch and U.S. Pat. No. 5,928,632 are directed to gelled mineral oil compositions wherein the mineral oil is gelled by a specific oil soluble copolymers (ethylene/propylene/styrene/ and butylene/ethylene/styrene). No mention is made of structured oils wherein the structurant forms a network of finely divided solids, nor the criticality of the rheological properties of such networks, or of the droplet size. Also there is no mention of structured oils comprising a dispersed phase.
Further, the compositions described in U.S. Pat. No. 5,578,299 to Starch and U.S. Pat. No. 5,928,632 although they deposit on skin, are still perceived as greasy.
U.S. Pat. No. 5,661,189 to Grieveson et al is directed to an aqueous cleansing and moisturizing composition containing a dispersion of a thickened benefit agent. No mention is made of the criticality that the composition should have a mildness index as measured by the zein solubility test below a specific value (essentially equal to water). Furthermore, there is no mention that the compositions of U.S. Pat. No. 5,661,189 must have a foam generation index below a critical value as measured by the shake test (essentially non-foaming), and no mention that the thickening agents must be limited to structurants that specifically form a network of finely divided solids having the properties defined herein.
Finally, applicants have filed an application also entitled “Wet-Skin Treatment Compositions” on May 17, 2001, U.S. Ser. No. 09/859,862. This reference does not specifically disclose, as does the subject application, that structured oil phase also comprises a dispersed phase inside the structured oil phase.
There remains a need for compositions that can be applied to wet skin, absorb quickly and are perceived to be effective skin treatments and provide natural looking and natural feeling skin.
One objective of the current invention is to provide a composition in which the benefit agent efficiently deposits on wet-skin and is retained to a high degree when the skin is subsequently rinsed and dried.
A further objective is to provide a composition in which the oil phase is perceived to rapidly absorb when the composition is applied and rubbed on the wet skin.
A further objective is to provide a composition that is perceived to moisturize and protect the skin while still being perceived to leave the skin clean and with a natural look and a moisturized feel.
A still further objective of the present invention is to provide a convenient method to moisturize and treat the skin to yield an enduring effect that can be accomplished conveniently and routinely in a single step as part of the bathing process. Such a process will obviate the need for separate treatments.
Applicants have found that these and other objectives can be realized through the use of oil-in-water compositions in which the oil phase is specifically structured through a network comprising finely divided solid particle and the structured phase and the composition posses specific functional properties according to the tests described herein. Moreover, the structured oil phase comprises a dispersed phase comprising inorganic particles, organic particles and/or droplets of water-soluble ingredients.
BRIEF DESCRIPTION OF THE INVENTION
The subject invention provides skin care treatment compositions that are designed for use during bathing comprising an aqueous dispersion of one or more water-insoluble skin compatible oils which is structured by a stable network of finely divided solid particles and which structured oil phase comprises a dispersed phase. Provided the composition meets specific requirements in the tests set forth herein, the applicants have obtained compositions that are perceived to absorb quickly on wet skin, and impart their benefits while leaving the skin feeling non-greasy/oily after rinsing and/or drying.
More specifically, the invention provides a wet-skin treatment composition, comprising:
a) an aqueous phase comprising water and a dispersion stabilizer;
b) a structured oil phase comprising:
i) a liquid, skin compatible oil;
ii) a structurant that forms a stable network of finely divided solids in said liquid skin compatible oil at a temperature below 35° C. and wherein said structurant is present in an amount sufficient to cause said oil phase to have a viscosity of 100 to 5000 poise measured at 1 sec-1 at 25° C.; and
iii) a dispersed phase (preferably comprising about 1-40% of the structured oil phase) within the structured oil phase;
wherein said dispersion-containing oil phase is itself dispersed and stabilized in said aqueous phase to form an oil-in-water emulsion having a weight average droplet size of 1-500 microns and the weight average drop size of the structured oil is at least 10 times larger than the size of particles dispersed inside the structured oil;
wherein said structured oil phase is capable of being efficiently retained on the skin upon rinsing as measured by a Skin Retention Efficiency Index of at least 0.15 as determined in the In-Vitro Skin Retention Test,
wherein said wet skin treatment composition has a Zein Solubility below 0.3 as measured by the Zein Solubility Test, and a Foam Volume below 5 cc as measured in the Solution Shake Test.
DETAILED DESCRIPTION OF THE INVENTION
The inventive composition described herein is designed for use as part of the bathing process to essentially treat the skin after it has been cleansed but while it is wet. To be of most utility, the composition should behave in an optimal fashion when it is used. Firstly the composition should be capable of depositing its beneficial ing

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