Toilet – Methods – Hair treatment by application of specific chemical composition
Reexamination Certificate
2001-09-24
2004-09-14
Wilson, John J. (Department: 3732)
Toilet
Methods
Hair treatment by application of specific chemical composition
Reexamination Certificate
active
06789550
ABSTRACT:
The present invention relates to a process for the temporary lightening and/or dyeing of the hair by vaporizing a solution of a polymer which forms, after evaporation of the solvent, a light-coloured opaque deposit, to a composition intended to be used in this process and to an aerosol device for carrying out this process.
The bleaching of human keratin fibres, in particular the hair, is generally carried out by oxidation of melanin resulting in the dissolution and partial or total removal of this pigment.
This chemical treatment with oxidizing and alkaline agents is often very harsh and modifies the chemical structure of the keratin, thus resulting in a degradation of the keratin fibres and change in the cosmetic properties of the hair.
The use of oxidizing lightening treatments is moreover relatively long and complex. The final nature of the lightening obtained may appear at first sight to be advantageous. However, the durability of the effect involves, during the regrowth of the hair, renewal of the treatment at regular intervals, thus making this type of treatment fairly restrictive.
A lightening treatment which is practical to use and which would not induce degradation of keratin fibres would consequently constitute a considerable advance in the field of hair treatment.
The Applicant has discovered, quite unexpectedly, that the application to the hair of certain crystalline hot-melt polymers in aerosol form gives rise to the formation of light-coloured opaque polymeric deposits.
The lightening effect thus obtained is temporary since the opaque polymeric deposit may be removed by simply washing the hair. The fugacity of this lightening is an advantage. Specifically, since the simplicity of the treatment and the total absence of degradation of the keratin fibres no longer prohibits multiple applications, the lightening process of the present invention allows great freedom of use. The user may thus vary the intensity and localization of the lightened zones as desired.
Moreover, the addition of colorants or pigments to the lightening solution containing the said crystalline hot-melt polymer makes it possible to obtain coloured shades which the user may combine in total freedom, with each other or with items of his or her wardrobe.
One subject of the present invention is thus a process for the temporary lightening and/or colouring of the hair, which consists in applying to dry hair by vaporization a lightening solution containing, dissolved in a cosmetically acceptable medium, at least one crystalline hot-melt polymer having a crystal melting point, measured by differential scanning calorimetry, of between 30° C. and 80° C., and at least one cosmetically acceptable volatile solvent having a boiling point of less than 90° C., so as to form, after evaporation of the solvent, a light-coloured opaque deposit.
A subject of the invention is also a composition for the temporary lightening and/or colouring of the hair, which composition comprises a lightening solution containing, dissolved in a cosmetically acceptable medium, at least one crystalline hot-melt polymer having a crystal melting point, measured by differential scanning calorimetry, of between 30° C. and 80° C., and at least one cosmetically acceptable volatile solvent having a boiling point of less than 90° C.
Another subject of the present invention is an aerosol device for carrying out the above process of temporary lightening and/or colouring of the hair, this device consisting
of a container containing an aerosol composition formed from a propellent compound and a liquid phase which is a lightening solution containing, dissolved in a cosmetically acceptable medium, at least one crystalline hot-melt polymer having a crystal melting point, measured by differential scanning calorimetry, of between 30° C. and 80° C., and at least one cosmetically acceptable volatile solvent having a boiling point of less than 90° C., and
of a means for distributing the said aerosol composition, which is suitable to create vaporization conditions for forming a light-coloured opaque deposit.
The present invention thus makes it possible by simple vaporization of a lightening solution onto dry hair, for example using the aerosol device described in greater detail below, to obtain, within a few tens of seconds after evaporation of the solvent, a light, more or less opaque, optionally coloured deposit. The coating thus deposited on the hair has no “powdering” effect, that is to say it does not have the appearance of a powder sprayed onto the hair and shows good resistance to mechanical stresses.
The crystalline hot-melt polymers which may be used according to the present invention for the temporary lightening and/or colouring of the hair are preferably crystalline copolymers comprising
i) from 85% to 98% by weight of hydrophobic units and
ii) from 2% to 15% by weight of hydrophilic units.
The hydrophobic units are derived from &agr;,&bgr;-ethylenic monomers containing a C
12-50
and preferably C
12-24
n-alkyl side chain, forming crystalline homopolymers known in the literature as side chain crystalline polymers. They are in particular C
12-50
and preferably C
14-24
n-alkyl acrylates and methacrylates.
The hydrophilic units are preferably derived from &agr;,&bgr;-unsaturated C
3-6
monocarboxylic acids such as acrylic acid, methacrylic acid or crotonic acid, unsaturated C
4-6
dicarboxylic acids such as maleic acid and itaconic acid, or esters and amides containing a C
1-4
alkyl chain of these monocarboxylic or dicarboxylic acids, such as C
1-4
alkyl (meth)acrylates and N-(C
1-4
alkyl) (meth)acrylamides.
The synthesis of these polymers is described in particular in international patent application Wo 98/25710.
Hydroxyethyl methacrylate or vinylpyrrolidone may also be used as hydrophilic units.
The carboxylic acid groups of the hydrophilic units are preferably partially or totally neutralized with a base chosen, for example, from sodium hydroxide, potassium hydroxide, 2-amino-2-methylpropanol, monoethanolamine, triethanolamine and triisopropanolamine.
The crystalline hot-melt polymers which may be used in the present invention are moreover characterized by a relatively low crystal melting point, that is to say a melting point of between 30° C. and 80° C. This relatively low melting point allows the polymers to be removed easily by simply washing the hair with water having a temperature above the melting point of the polymer.
The crystal melting point of the polymers which may be used in the present invention is measured by differential scanning calorimetry.
The heat of fusion of a polymer is the amount of energy required to convert a partially or totally crystalline sample into a totally amorphous sample. The thermogram &Dgr;Cp=f(T), in which &Dgr;Cp represents the difference in heat capacity of the sample relative to a reference sample which has undergone no thermal transition in the range studied, thus has an endothermal signal whose area is proportional to the heat of fusion of the sample.
The melting point of the crystalline polymers which may be used in the present invention is measured using a differential scanning calorimetry (DSC) machine, model M2920CE-5010 sold by the company TA Instruments. The sample is heated, at a rate of 10° C./minute, from −20° C. to +150° C., and the difference in heat capacity between the sample and the control is recorded as a function of the temperature.
The temperature corresponding to the top of the endothermal peak for fusion of the crystal zones which is thus obtained is known as the crystal melting point (T
f
).
Mention may be made, by way of example, of crystalline polymers with a low melting point such as those described above, of a copolymer sold under the name Structure® O by the company National Starch. It is a random copolymer consisting of 10% by weight of units derived from acrylic acid and 90% by weight of units derived from n-octadecyl methacrylate. This polymer has a crystal melting point, measured by differential scanning calorimetry, of 46° C.
The hot-melt crystalline
Giroud Franck
Samain Henri
Doan Robyn Kieu
Jacobson & Holman PLLC
L'Oreal
Wilson John J.
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