Drug – bio-affecting and body treating compositions – Live hair or scalp treating compositions – Polymer containing
Reexamination Certificate
1999-12-17
2002-02-12
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Live hair or scalp treating compositions
Polymer containing
C424S070100, C424S401000, C514S844000, C514S939000, C514S944000, C514S945000
Reexamination Certificate
active
06346239
ABSTRACT:
BACKGROUND OF THE INVENTION
The present patent application relates to thickening water-in-oil latices, to a process for their preparation and to their use as thickeners and/or emulsifiers for skincare and haircare products or for the manufacture of cosmetic, dermopharmaceutical or pharmaceutical preparations.
DESCRIPTION OF THE RELATED ART
Various thickeners exist and are already used for these purposes. Natural products such as guar gums or starch are known in particular, but the drawbacks thereof are those inherent in natural products, such as currency fluctuations, difficulties in supply and a random quality.
Synthetic polymers in powder form, mainly polyacrylic acids, are also widely used but have the drawback of requiring neutralization during use, since they only develop their viscosity from a pH of greater than 6.5 and they are often difficult to dissolve.
Synthetic thickening polymers which are in the form of reverse latices, i.e. latices in which the continuous phase is an oil, also exist. These latices dissolve extremely quickly; the polymers contained in these reverse latices are usually acrylamide/alkali metal acrylate or acrylamide/sodium 2-acrylamido-2-methylpropanesulphonate copolymers; they are already neutralized and, when dissolved in water, for example to a concentration of 1%, it is observed that the pH is generally greater than 6.
However, acrylamide/sodium acrylate copolymers do not develop considerable thickening properties when the pH is lowered below 6; on the other hand, the acrylamide/sodium 2-acrylamido-2-methylpropane-sulphonate copolymers described in EP 0 503 853 conserve considerable thickening capacity even at a pH equal to 4.
However, such copolymers have monoacrylamide contents which, although extremely low, may lead in the future to their use in cosmetics not being possible, on account of the changes in European regulations regarding hazardous substances.
Furthermore, all of the polymers mentioned have a tendency to lose their thickening property when the medium to be thickened, for example a cosmetic product, contains salts; this tendency becomes accentuated as the concentration of salts present in the said medium increases.
SUMMARY OF THE INVENTION
The Applicant has thus become interested in the search for novel acrylamide-free reverse emulsions which are more stable with respect to electrolytes.
According to a first aspect of the present invention, its subject is the use of a composition comprising an oil phase, an aqueous phase, at least one emulsifier of water-in-oil (W/O) type and at least one emulsifier of oil-in-water (O/W) type, in the form of a reverse latex comprising from 20% to 70% by weight, and preferably from 25% to 40% by weight, of an anionic polyelectrolyte, the said anionic polyelectrolyte being based on partially neutralized acrylic acid, which may be branched and/or crosslinked, to prepare a cosmetic, dermopharmaceutical or pharmaceutical composition.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The expression “emulsifier of water-in-oil type” denotes emulsifiers with an HLB value which is low enough to give water-in-oil emulsions, such as the surfactant polymers sold under the name Hypermer™ or such as sorbitan esters, for instance sorbitan monooleate sold by the company SEPPIC under the name Montane™ 80 or sorbitan isostearate sold by SEPPIC under the name Montane™ 70.
The expression “emulsifier of the oil-in-water type” denotes emulsifiers with an HLB value which is high enough to give oil-in-water emulsions, such as, for example, ethoxylated sorbitan esters, for instance sorbitan oleate ethoxylated with 20 mol of ethylene oxide or sorbitan laurate ethoxylated with 20 mol of ethylene oxide, sold by the company SEPPIC under the names Montanox™ 80 and Montanox™ 20, respectively, castor oil ethoxylated with 40 mol of ethylene oxide or alternatively lauryl alcohol ethoxylated with 7 mol of ethylene oxide, sold by the company SEPPIC under the names Simulsol™ OL 50 and Simulsol™ P7, respectively.
The expression “partially neutralized acrylic acid” denotes more particularly acrylic acid partially salified in the form of an alkali salt, such as the sodium or potassium salt, or in the form of the salt of a nitrogenous base, such as the ammonium salt, or a salt with a compound containing quaternary ammonium, such as an amino alcohol salt. It is preferably acrylic acid partially neutralized in the form of the ammonium salt (NH
4
+
) or a monoethanolamine salt (HOCH
2
CH
2
NH
3
+
).
The expression “branched polymer” denotes a non-linear polymer which contains pendant chains so as to obtain, when this polymer is dissolved in water, a strong state of entanglement leading to very high low-gradient viscosities.
The expression “crosslinked polymer” denotes a non-linear polymer which is in the form of a three-dimensional network which is insoluble in water but swellable in water and thus leads to the production of a chemical gel.
The composition according to the invention can comprise crosslinked units and/or branched units.
The term “amino alcohol” means mono- or poly(hydroxyalkyl)amines.
A subject of the invention is, more particularly, the use, as defined above, of a composition in which the anionic polyelectrolyte is crosslinked and/or branched with a crosslinking agent and/or a branching agent chosen from trimethylolpropane triacrylate, ethylene glycol dimethacrylate or methylenebis(acrylamide) or compounds comprising at least two allyl radicals such as, for example, diallyloxyacetic acid or a salt thereof such as sodium diallyloxyacetate, triallylamine or diallylurea.
The crosslinking and/or branching agent is generally used in a molar proportion, expressed relative to the monomers used, of from 0.05% to 0.5% and preferably from 0.1% to 0.25%.
The latex according to the invention generally contains from 2.5% to 15% by weight and preferably from 4% to 9% by weight, of emulsifiers, among which from 20% to 50%, in particular from 25% to 40%, of the total weight of the emulsifiers present are of the water-in-oil (W/O) type and in which from 80% to 50%, in particular from 75% to 60%, of the total weight of the emulsifiers are of the oil-in-water (O/W) type.
According to one specific aspect of the present invention, the oil phase of the composition used represents from 15% to 40%, preferably from 20% to 25%, of the total weight of this composition.
This oil phase consists either of a commercial mineral oil containing saturated hydrocarbons of paraffin, isoparaffin or cycloparaffin type, with a density at room temperature of between 0.7 and 0.9 and a boiling point of greater than 180° C., such as, for example, Exxol™ D 100 S sold by Exxon or a white mineral oil such as Marcol™ 52 also sold by Exxon, the isohexadecane sold by Bayer or isododecane, or of a plant oil such as hexamethyltetracosane or squalane, or of a synthetic oil such as polyisobutene or hydrogenated polyisobutene, or of a mixture of several of these oils.
The isohexadecane, which is identified in Chemical Abstracts by the number RN=93685-80-4, is a mixture of C
12
, C
16
and C
20
isoparaffins containing at least 97% C
16
isoparaffins, among which the main constituent is 2,2,4,4,6,8,8-heptamethylnonane (RN=4390-04-9). It is sold in France by the company Bayer. Marcol™ 52 is a commercial oil corresponding to the definition of liquid petroleum jellies in the French Codex. It is a white mineral oil in accordance with the rules FDA 21 CFR178.878 and CFR 178.3620(a); it is registered in volume US XXIII of the USA Pharmacopoeia (1995) and in the European Pharmacopoeia (1993).
According to one preferred aspect of the present invention, the oil phase of the composition used comprises isohexadecane or a white mineral oil.
The latices contain between 20% and 50% water. They can also contain various additives such as complexing agents, transfer agents or chain-limiting agents.
According to a second aspect of the present invention, its subject is a composition as employed in the use defined above, comprising an oil phase, an aqueous phase, at least one emulsi
Boiteux Jean Pierre
Mallo Paul
Tabacchi Guy
Page Thurman K.
Societe d'Exploitation de Produits Pour les Industries Chim
Ware Todd D
Young & Thompson
LandOfFree
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