Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1998-08-25
2002-10-22
Travers, Russell (Department: 1617)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S061000, C424S063000, C424S064000, C424S069000, C424S070600, C424S070700, C424S617000, C424S677000, C424S679000, C424S680000, C424S696000, C424S697000
Reexamination Certificate
active
06468550
ABSTRACT:
Applicant references herein the patent application of CHRISTOPHE REMY for PROCESS FOR THE PREPARATION OF PHOTOCHROMIC TITANIUM OXIDE, COMPOUND OBTAINED AND COMPOSITION COMPRISING IT filed on even date herewith and incorporates the disclosure thereof specifically by reference herein.
The present invention relates to the improvement of the photochromic properties of an initially photochromic inorganic compound, and to its application in the field of cosmetic compositions in particular.
Cosmetic compositions, in particular make-up compositions such as free or compact powders, foundations, blushers or eye-shadows, lip compositions or nail varnishes, consist of a suitable vehicle and various colorants intended to impart some degree of colour to the said compositions before and/or after they are applied to the skin, the mucous membranes, the mucocutaneous tissues and/or parts of the exoskeleton, for example the nails or the hair.
A fairly limited range of colorants is presently used to create colours, in particular lakes, inorganic pigments or pearlescent pigments. Lakes allow vivid colours to be obtained, but are for the most part unstable with respect to light, temperature or pH. Some of them also have the drawback of staining the skin unattractively after they have been applied, as a result of the colorant being leached. Conversely, inorganic pigments, in particular inorganic oxides, are highly stable but give somewhat dull and pale colours. In order to obtain coloured effects, use may also be made of pearlescent pigments whose. colours are varied, albeit never intense, which make it possible to obtain iridescent but, most often fairly weak effects.
It has therefore been proposed to use photochromic compounds in make-up or haircare compositions, so as to obtain attractive and varied changes in the colour effect of make-up for the skin and/or the hair.
Photochromic compounds are compounds which have the property of changing colour when they are exposed to a light source, then of returning to their initial colour, or a similar colour, when they are no longer being exposed. In particular, compounds of this type have a particularly advantageous application in cosmetic compositions, in particular in make-up compositions such as foundations and blushers or eye-shadows. Indeed, it has been found that the make-up effect of skin which has been made up differs depending on. whether the illumination is natural or artificial. Thus, make-up applied under artificial illumination will appear lighter under natural light. Conversely, make-up applied out of doors will appear darker in a place where the illumination is artificial.
In particular, it has been proposed to use organic photochromic compounds, for example-compounds of the spiropyran or naphthoxazine families.
These photochromic compounds are particularly advantageous since they enable the support to which they are applied to change colour rapidly when the support is exposed to UV, for example, with a rapid return to the initial colour when it is no longer being exposed to UV.
Mention may thus be made of French patent FR1604929, which describes cosmetic compositions, in particular for the hair and in aerosol form, which contain phototropic compounds such as nitrobenzylpyridines, thiosemicarbazones or spiropyran derivatives. After these compositions have been sprayed onto the hair and exposed to sunlight, a blue violet coloration is obtained which returns to pale yellow in darkness.
Cosmetic compositions comprising particular inorganic photochromic compounds, selected from metal oxides, their hydrated forms and their complexes, have also been proposed, for example by European patent EP359909. In particular, this document mentions the use of titanium oxide, treated so as to make it photochromic, in make-up compositions such as powders and foundations.
However, it has been observed that, even though they make it possible to obtain a make-up which seems to keep a constant colour irrespective of the nature of the; illumination, these photochromic compounds, in particular inorganic ones, nevertheless do not make it possible to obtain a true change in the colour of the make-up, or in other words. a true change in the make-up effect.
Furthermore, it has also been observed that, when it is no longer being exposed to light, the colour of the make-up does not always return acceptably to its initial colour, and in particular does not return completely to a colour identical to the initial colour.
The object of the invention is to provide a particular process for improving the photochromism, that is to say the photochromic properties, of an initially photochromic inorganic compound.
The photochromic properties of a compound can be characterized using trichromatic coordinates (L, a and b) in the way described before the examples. These coordinates make it possible, in particular, to determine the parameters &Dgr;E30 and &Dgr;(&Dgr;E) which will be used in the present application to characterize the photochromism of the compounds, according to the invention and outside the scope of the invention.
In general, the higher the parameter &Dgr;E30, the more capable the compound is to change colour after being exposed. The higher the parameter &Dgr;(&Dgr;E) is, the greater is the ability of the compound to return to its initial colour.
Thus, the object of the invention is therefore, in particular, to improve the parameters &Dgr;E30 and &Dgr;(&Dgr;E) of the composition, that is to say to obtain the highest possible parameters.
The present invention therefore relates to the use of an ionic conductor in a composition comprising an inorganic photochromic compound, in order to improve the photochromism of the composition.
The invention also relates to a composition comprising at least one inorganic photochromic compound and at least one ionic conductor.
One advantage of the invention is that it makes it possible, in the cosmetic compositions according to the invention, to use an amount of photochromic compositions which is smaller than that used in the prior art, while obtaining a comparable make-up effect and covering power.
Another advantage of the invention is that it makes it possible, for the same amount of photochromic compounds, to obtain improved photochromic properties, that is to say an enhanced colour change and/or a return to the initial colour which is also enhanced.
Without being limited by the present explanation, the mechanism making it possible to improve the photochromic properties of a given compound may be as follows. An iron doped photochromic titanium oxide will be considered. When exposed to UV, it can be considered that the cation Fe
3+
will give up an electron to an entity X which will be converted into an entity X
−
, responsible for the colour change of the said photochromic compound. It may be assumed that, during a second phase, electrons in the valence band of the titanium oxide will then be moved to the conduction band, consequently generating both free electrons, which can be picked up by X to form X
−
, and electron vacancies in the, valence band, which are also referred to as positive “holes”, that is to say a vacant state in an energy band corresponding to a region with a negative charge in deficit.
The invention involves promoting the transfer of electrons within photochromic titanium oxide so as to improve its photochromic properties.
The term “ionic conductor” is used according to the invention to mean any compound which can be separated into cations and anions when it is dissolved in water or an aqueous medium.
The ionic conductor is preferably selected from the salts of alkali or alkaline-earth metals; mention may in particular be made of the chlorides of sodium, lithium, potassium, and the sulphates of magnesium or calcium, alone or as a mixture.
The ionic conductor may be incorporated into the composition in an amount which can be readily determined by the person skilled in the art on the basis of his general knowledge, in order to obtain the desired effect; this amount may preferably range from 0.5 to 30%
Berman Alysia
L'Oreal (S.A.)
Travers Russell
LandOfFree
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