Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
2001-04-26
2003-08-12
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S070110, C424S070220, C424S070310, C424S070210, C514S937000
Reexamination Certificate
active
06605290
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an aerated composition comprising an associative polymer and an anionic surfactant and to its use in particular for treating and/or cleansing human skin, including the scalp, nails and/or hair, in particular for caring for dry skin and/or dry lips, and for making up the skin.
2. Description of the Related Art
Users of skin care products are increasingly looking for products which are pleasant to use and which have a novel texture. Until now, cosmetic compositions have been generally provided in the form of solutions, gels or more or less fluid creams.
Creams are conventionally composed of an emulsion. Emulsions comprise an aqueous phase and an oily phase dispersed in one another. Oil-in-water (O/W) emulsions, the external phase of which is the aqueous phase, are more particularly desired because they contribute more freshness on application than water-in-oil (W/O) emulsions comprising an oily external phase. Their feel and their application seem to be less greasy than those of a W/O emulsion. In addition, they make possible a high level of moisturizing, which is particularly useful in caring for dry skin or lips.
In order to confer a novel texture on emulsions, attempts have been made to introduce a gas, generally air, therein in order to confer on them a light texture and to give them the appearance of a foam. This is what is known as expansion. The aerated emulsions obtained are appreciated for their lightness on application. Nevertheless, they exhibit the disadvantage of being relatively unstable because of their low relative density and thus of separating out after a certain storage time. The application CH-A-674,804 discloses stabilization of an aerated cosmetic cream comprising an inert gas or air by the addition of an aqueous solution of a protein of animal origin. However, the use of such proteins is avoided in cosmetics.
Furthermore, the application JP-A-56/079613 discloses stable aerated surfactant-free compositions comprising from 5 to 20% of waxes, preferably waxes with a high melting point. The emulsions obtained are then stable but exhibit cosmetic properties which are unacceptable to the user. This is because these compositions comprise very little water and therefore lack freshness when applied to the skin. In addition, they comprise a significant amount of humectants, such as glycerol, which leads to a feeling of stickiness to the touch. In addition, the use of a wax with a high melting point in an amount of 5% results in heavy textures which are very difficult to apply to the skin.
The need thus remains for an emulsion which has the appearance of a foam, while comprising a large amount of water, and which is fresh and not sticky when applied to the skin.
SUMMARY OF THE INVENTION
The Inventors have found, unexpectedly, that the use of associative polymers in combination with an anionic surfactant makes it possible to obtain an aerated emulsion having the desired properties. An associative polymer is an amphihilic polymer, i.e., a polymer which comprises at least one fatty chain and hydrophilic units.
Accordingly, the present invention provides an aerated composition suitable for application to human skin, comprising:
an oily phase dispersed in an aqueous phase;
air or an inert gas;
at least one amphiphilic polymer; and
at least one anionic surfactant,
wherein the composition has a relative density ranging from 0.2 to 0.8.
The present invention also provides a method of treating, protecting, caring for, removing make-up from and/or cleansing the skin, lips and/or hair and/or for making up the skin and/or lips, comprising applying the inventive composition to the skin, lips and/or hair.
A subject-matter of the invention is consequently an aerated composition comprising, in a physiologically acceptable medium, an oily phase dispersed in an aqueous phase, characterized in that it contains air or inert gas in a sufficient amount to have a relative density ranging from 0.2 to 0.8 and in that it comprises at least one amphilic polymer and at least one anionic surfactant.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description.
DETAILED DESCRIPTION OF THE INVENTION
The composition of the invention exhibits a relative density which is lower than that of a conventional emulsion and yet nevertheless remains very stable over time (several months at room temperature). The aerated composition of the invention comprises air or inert gas bubbles and has a relative density ranging from 0.2 to 0.8 (g/cm
3
) and preferably from 0.4 to 0.75, this relative density being measured at a temperature of approximately 25° C. and at atmospheric pressure. Inert gas may be nitrogen, helium or argon, or a mixture thereof. A mixture of air and any of these inert gases may also be used. The amount of air or inert gas necessary to obtain the wanted density is of at least 30% by volume, and it may range for example from 40 to 80% by volume, and preferably from 50 to 70% by volume with respect to the total volume of the composition.
The composition of the invention differs from foams obtained with a propellant (such as isobutane), such as shaving foams, by the fact that it stays as a stable foam over time, contrary to shaving foams which break down very quickly.
The composition of the invention advantageously comprises a physiologically acceptable medium, that is to say compatible with the skin, eyes and/or hair, and it can constitute in particular a cosmetic and/or dermatological composition.
This composition is an O/W (oil-in-water) emulsion which is neither greasy nor heavy and, as the external phase is the aqueous phase, it gives an impression of freshness on application to the skin.
The polymers which can be used in the present invention are amphiphilic polymers which comprise at least one fatty chain, therefore a hydrophobic part, and hydrophilic units, therefore a hydrophilic part. They are known as associative polymers because the percentage and/or the sizes of the hydrophobic groups are such that the said hydrophobic groups are capable of forming an association, in aqueous medium, with other hydrophobic groups.
The hydrophobic part can be in reduced number with respect to the remainder of the polymer chain, can be situated in the pendant position on the chain and can be distributed randomly (random copolymers) or distributed in the form of sequences or grafts (block copolymers or sequential copolymers).
The polymers which can be used in the composition of the invention can be soluble in water or dispersed in water to give microgels. These polymers are known as “swellable” in water. The polymers can be of any chemical nature; it is thus possible to choose optionally modified polymers of natural origin; radical polymers, in particular of vinyl or acrylic polymers; polycondensates; and their mixtures. These polymers can be ionic or nonionic and they are preferably anionic or nonionic.
Examples of optionally modified polymers of natural origin which can used in the composition of the invention include:
1) cellulose ethers possessing hydrophobic substituents, which substituents can be alkyl groups having a carbon number equal to or greater than 8. Examples of cellulose ethers of this type include, for example, hydroxyethylcellulose substituted by hydrophobic groups, such as the product sold under the name Natrosol Plus Grade 330 by Aqualon;
2) quaternized cationic celluloses modified by groups comprising at least one fatty chain, such as alkyl, arylalkyl or alkylaryl groups or their mixtures where the alkyl groups are preferably C
8
-C
22
groups;
3) quaternized (cationic) alkylhydroxyethylcelluloses, such as the products sold under the names Quatrisoft LM 200, Quatrisoft LM-X 529-18-A, Quatrisoft LM-X 529-18-B (C
12
alkyl) and Quatrisoft LM-X 529-8 (C
18
alkyl) by Amerchol and the products sold under the names Crodacel QM, Crodacel QL (C
12
alkyl) and Crod
Daubig Therese
Roulier Veronique
Fubara Blessing
L′Oreal
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Page Thurman K.
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