Colloid systems and wetting agents; subcombinations thereof; pro – Continuous gas or vapor phase: colloid systems; compositions... – Discontinuous phase primarily liquid
Reexamination Certificate
1997-03-06
2001-12-25
Metzmaier, Daniel S. (Department: 1712)
Colloid systems and wetting agents; subcombinations thereof; pro
Continuous gas or vapor phase: colloid systems; compositions...
Discontinuous phase primarily liquid
C424S045000, C424S047000, C510S130000, C510S135000, C510S140000
Reexamination Certificate
active
06333362
ABSTRACT:
The invention relates to new pressurized devices containing oil-in-water emulsions that have a good ability to foam, and the use of such an emulsion for topical uses, in particular, for cleansing and care of the skin.
Cleansing of the skin is very important for facial care. It must be as effective as possible because the fatty residues, such as the excess of sebum, the remainders of cosmetic products employed daily, and the make-up products, especially the water-resistant “waterproof” products, accumulate in skin folds and can block the pores of the skin and result in the appearance of pimples.
Two major types of skin-cleansing products are known: foaming detergent aqueous lotions and gels and rinsable cleansing anhydrous oils and gels.
Foaming detergent aqueous lotions and gels have a cleansing action by virtue of the surfactants therein which suspend the fatty residues and the pigments of the make-up products. They are effective and cosmetically pleasant because they foam and they are easily removed. Insofar as they do not contain any cosmetic oil, they have the disadvantage of drying the skin by their dilapidating action. This is the case, for example, with the products described by document WO95/05796, which teaches skin-cleansing lotions which are very fluid and pressurizable and which produce an attractive foam. These products, however, destroy the hydro-lipid film of the skin and leave the skin clean, but rough.
Rinsable anhydrous oils and gels have a cleansing action by virtue of the oils present in these formulations. These oils make it possible to solubilize the fatty residues and to disperse the make-up pigments. These products are effective arid well tolerated by the skin. They have the disadvantage of being heavy, of not foaming and of not imparting a sensation of coolness when applied, and this is disadvantageous from a cosmetic viewpoint.
Attempts have been made to solve these technical problems by producing creams and milks for removing make-up, simultaneously containing oils, emulsifiers and detergent surfactants in a quantity which is sufficiently low so as not to destabilize the emulsion. Despite their good effectiveness, these products are not foaming and have an insufficient rinsability, which makes it necessary to use an additional detergent tonic lotion to complete the rinsing and the removal of the soiling. In addition to its astringent nature, the use of this second product can, in the long term, result in drying of the skin.
What is sought after are foaming detergent products which are completely water-rinsable, containing hydrophilic surfactants and oils which simultaneously make it possible to optimize the cleansing of the skin and to hydrate and to nourish the latter in order to avoid any drying-out phenomenon.
Oils cannot merely be introduced into a detergent aqueous lotion or gel in order to produce a product which cleanses the skin without drying it out. In fact, oils have a tendency to inhibit the foaming properties of these formulations; it is said that oils “kill” the foam. In addition, the oil dispersion is unstable. Foaming emulsions, for example, emulsions for removing make-up are known, for example, from document WO95/17163. A product of this type is very mild and very well tolerated by the skin, but the foamability of these emulsions is low because of the presence of oils. Moreover, these emulsions are always opaque and relatively thick, and this does not allow them to be packaged in pressurized receptacles.
In the same way, foaming surfactants cannot merely be introduced into conventional creams or milks for removing make-up, which are oil-in-water emulsions, in order to obtain good foamability. When introduced in concentrations higher than 5% by weight, these surfactants result in the breaking of these emulsions, because they disturb the interfacial film formed by the emulsifier around the oil droplets in dispersion.
In addition, attempts have been made to prepare a pressurizable product. In fact, packaging in aerosol form is particularly advantageous because it allows a controlled distribution, better conservation of the product and, in addition, they have the appearance of a plaything as seen by the user.
It is known, for example from document WO89/11907, that the phase inversion method makes it possible to prepare pressurizable, ultrafine, stable, fluid oil-in-water emulsions. These emulsions are often packaged in the form of a pressurized composition and are restored into the form of sprays, without solvent and without volatile organic compounds. However, the emulsions prepared by the phase inversion method in the prior art are nonfoaming. In fact, the surfactants employed for making emulsions capable of inverting, or PIT emulsions, are nonfoaming nonionics, essentially polyethoxylated fatty alcohols, since other surfactants do not make it possible to obtain a phase inversion. From numerous investigations, which have been carried out around this subject, it is also known that the behavior of PIT emulsions is very sensitive to the components which are incorporated therein, it being very possible for an emulsion to lose its invertible character and to become destabilized under the effect of some additives. On this subject reference may be made, for example, to the following documents: T. Mitsui et al., Bulletin of the Chemical Society of Japan, vol. 43, 3044-3048 (1970) and T. Mitsui et al., American Cosmetics and Perfumery, vol. 87, 33-36 (1972). Until these discoveries, PIT emulsions were highly valued for their fluid character which gives them a great ease of application and of spreading on the skin.
Cleansing aqueous compositions for the body and hair are also renown, for example, from German document DE-A-4318171, these compositions include high proportions of ionic surfactants as well as an oil, which is introduced into the surface-active aqueous composition in the form of an ultrafine emulsion. However, this document does not mention or suggest the possibility of pressurizing such compositions.
Surprisingly and unexpectedly, the Inventor has overcome the disadvantages of the prior art by using so-called “ultrafine” specific oil-in-water emulsions (which will be denoted by O/W), wherein the size of the oil particles constituting the oil phase is within well-determined limits. The emulsions of O/W type are preferably obtained according to the so-called “phase inversion” technique, described in detail below. These ultrafine O/W emulsions can be employed in particular for the cleansing and care of the skin and are rich in oils, fluid, pressurizable, foaming, stable and translucent. They can also be pressurized and packaged in aerosol receptacles.
A subject of the present invention is thus an aerosol device comprising a pressurized receptacle provided with a means of dispensing including a valve, the receptacle containing a propellent gas and a foaming emulsion comprising:
(A) at least one cosmetic oil,
(B) at least one nonionic emulsifier having an HLB ranging from 9 to 18,
(C) at least one foaming surfactant, and
(D) water,
wherein the average size of the oil particles which constitute the oil phase of these emulsions ranges from 50 to 1000 nm.
When pressure is applied to the means of dispensing of the device according to the invention, the valve is actuated and the device restores and dispenses its contents in the form of a creamy foam. Products with such a consistency are particularly valued for the cleansing and the care of the skin or of hair.
Such a device usually contains from 0.5 to 20% of propellent gas and from 80 to 99.5% of emulsion. Any propellent gases known for such applications can be employed in the devices according to the invention. There may be mentioned, in particular, hydrocarbon gases like, for example, propane, isopropane and n-butane, isobutane and mixtures thereof; fluorine-containing gases like, for example, chlorodifluoromethane, dichlorodifluoromethane, difluoroethane, chlorodifluoroethane, dichlorotetrafluoroethane and the like, and mixtures thereof. Nitrogen and carbon dioxide and their mixtures can
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
L'Oreal
Metzmaier Daniel S.
LandOfFree
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