Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1995-04-21
2002-08-13
Venkat, Jyothsna (Department: 1627)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S063000, C424S064000, C424S069000, C424S070100, C424S070700, C424S078020, C424S078030, C424S078080, C424S078160, C424S078370
Reexamination Certificate
active
06432417
ABSTRACT:
The subject of the present invention is cosmetic compositions, containing a dispersion of solid particles, into which are introduced solid organic particles whose surface is coated with a cationic polymer.
It is known that various make-up products such as loose or compacted powders, foundations, blushers, eye shadows, as well as lipsticks, are provided in the form of compositions comprising a dispersion of solid organic particles in a fatty binder. They may be anhydrous compositions or else oil-in-water or water-in-oil emulsions.
Depending on the types of compositions, the solid organic particles are especially pigments (white and/or coloured), intended to confer on the skin of the face or lips a certain colouring, or even to colour the compositions themselves, or alternatively particles which act as fillers (in particular in compositions in the form of powders).
In lipsticks, the solid particles dispersed in an appropriate fatty binder are especially coloured pigments, optionally in combination with white pigments (for example fine particles of titanium dioxide) which make it possible to impart a shade to the colours provided by the coloured pigments.
Such coloured pigments are also used in nail varnish compositions which essentially consist of a dispersion of these pigments in a solution of a film-forming polymer and of a plasticizer in an appropriate organic solvent.
The preparation and use of the cosmetic compositions containing dispersions of solid particles pose several types of problem. One problem common to the preparation of all the compositions which have just been discussed lies in the difficulty of obtaining stable dispersions, so as to apply, for example to the skin, a regular make-up whose application is uniform and which retains a good homogeneity. For this, specialists have been led to perform surface treatments on the powders used, especially in order to modify the interfacial properties involved in the wetting and dispersion phenomena. The aim of these treatments is often to render the powder hydrophobic in order to enhance its incorporation into the formulation binders and oils, and to increase the stability of the dispersion by reducing the phenomena of flocculation and aggregation; see for example European Patent 279,319 which describes the coating of pigments with siliconized polymers.
These treatments therefore make it possible to solve the problems of stability of the dispersion by limiting the flocculation phenomena. However, they do not solve another important problem, namely the weak properties of adhesion of the solid particles to the skin. Indeed, it is known that the solid particles used especially in the compositions in the form of powders have only weak properties of adhesion to the skin. The surface treatments intended to improve the stablity of the dispersions in the fatty binders do not provide a substantial improvement as far as the adhesion properties are concerned.
It is known furthermore that the make-up products for the face and for the eyes are often provided in the form of compacted powders. The compacted powders are prepared by mixing the constituents of the powder with a binding agent and then converted to the desired form by compression in appropriate containers.
The compacted powders should exhibit special characteristics of hardness. The hardness is a function of the applied compacting pressure. If the compacted product is too soft, it will be highly brittle and too large a quantity of product will be removed at the time of application. In contrast, if it is too hard, the disintegration will be difficult. Furthermore, a compact product should exhibit a perfectly flat surface. Finally, it should respond favourably to the drop test, that is to say exhibit a reduced loss of weight after a drop performed under standardized conditions.
It has now been discovered that it is possible to obtain cosmetic compositions, comprising a dispersion of solid organic pigments in a binder, having good properties of stability and adhesion to the skin or to superficial body growths, by introducing into the said compositions solid organic particles whose surface has been coated with a cationic polymer. It was observed, surprisingly, that the coating of the solid organic particles with cationic polymers, which nevertheless constitute a hydrophilic coating, does not prevent a good dispersibility of the particles in the fatty binders from being obtained. In addition, the compacted compositions obtained with cationic polymer-coated solid organic particles surprisingly exhibit good cohesion properties which result especially in a very satisfactory behaviour in the drop test. Furthermore, the compositions thus obtained have good properties of adhesion to the skin or to superficial body growths (fingernails or nails), after application.
The subject of the present invention is therefore a cosmetic composition for the skin or superficial body growths (fingernails or nails), comprising a dispersion of solid organic particles in a binder, characterized in that at least a portion of the said organic particles are introduced into the said composition in the form of particles whose surface is coated with at least one cationic polymer.
In the compositions of the invention, solid organic particles are coated with the cationic polymer at the surface. This means that, after coating, there is neither a change in morphology nor notable modification in the sizes of the particles, as verifiable by electron microscopy.
In the present application, the expression “cationic polymer” denotes a polymer containing cationic groups or groups which can be ionized to cationic groups.
The preferred cationic polymers are chosen from those containing units comprising primary, secondary, tertiary and/or quaternary amine groups which may either form part of the polymer chain or be carried by a side substituent.
The cationic polymers used preferably have a molecular mass of between 10
3
and 3×10
6
, approximately.
Preferably, the coated organic particles used in the compositions of the invention are coated solely with one (or more) cationic polymer(s).
The cationic polymers used are in particular those having a quaternization value, expressed as cationic equivalents per gram of polymer, of at least 0.05 cationic meq/g. Use is especially made of cationic polymers which contain for example at least 10% by weight of units comprising amine or quaternary ammonium groups.
When the cationic polymer contains amine or quaternary ammonium groups carried by a side substituent, the polymer chain is for example an acrylic, vinyl, siliconized, fluorinated or saccharide chain.
Among the cationic polymers, there may be mentioned more particularly quaternized proteins (or protein hydrolysates), quaternized polysiloxanes and polymers of quaternary polyammonium, polyaminoamide and polyamine type. These are known products.
Use is preferably made of cationic polymers which do not contain silicon, that is to say other than siliconized polymers.
It is more particularly preferable to use, as cationic polymer, a polymer containing ionized tertiary, secondary or primary amine group(s) or containing quaternary ammonium group(s), the latter being preferred.
The quaternary ammonium group may especially be obtained by quaternization of amino groups with conventional quaternization agents such as alkyl or aralkyl halides (for example methyl iodide, ethyl bromide or benzyl chloride), alkyl sulphates (for example dimethyl sulphate), and the like.
The ionized amine groups are obtained by salification of the amino groups with organic or inorganic acids such as hydrochloric, hydrobromic, lactic, acetic and glycolic acids and the like.
The quantities of polymer deposited on the particles vary with the procedure used for the coating. Generally, the proportion by weight of cationic polymer, relative to the total weight of the coated particles, is at least equal to 0.1%; the upper limit of the quantity of cationic polymer is sufficiently low for the particles to retain their individuality and their shape. In other words,
Candau Didier
Mellul Myriam
L'Oreal
Nixon & Vanderhye P.C.
Venkat Jyothsna
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