Drug – bio-affecting and body treating compositions – Live hair or scalp treating compositions – Polymer containing
Reexamination Certificate
1999-01-19
2001-03-06
Bawa, Raj (Department: 1619)
Drug, bio-affecting and body treating compositions
Live hair or scalp treating compositions
Polymer containing
C424S401000, C514S844000, C514S939000, C514S944000, C514S945000
Reexamination Certificate
active
06197287
ABSTRACT:
FIELD OF THE INVENTION
The present application relates to thickening water-in-oil latices, to a process for their preparation and to their application as thickeners and/or emulsifiers for skincare products and haircare products or for the manufacture of cosmetic, dermopharmaceutical or pharmaceutical preparations.
BACKGROUND OF THE INVENTION
Various thickeners exist and are already used for these purposes. Natural products such as guar gum or corn starch are known in particular, the drawbacks of which are those inherent to natural products, such as price fluctuations, supply difficulties and random quality.
Synthetic polymers in powder form, mainly polyacrylic acids, are also widely used but have the drawback of requiring neutralization when they are used, since they only develop their viscosity from a pH >6.5 and they are often difficult to dissolve.
Synthetic thickening polymers in the form of an inverted latex, that is to say one in which the continuous phase is an oil, are also known. These latices dissolve extremely quickly; the polymers contained in these inverted latices are usually acrylamide/alkali metal acrylate copolymers or acrylamide/sodium 2-acrylamido-2-methylpropane-sulphonate co-polymers; they are already neutralized and when they are dissolved in water, for example to a concentration of 1%, it is observed that the pH is generally above 6.
However, acrylamide/sodium acrylate copolymers do not develop any appreciable 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 retain an appreciable thickening capacity even at pH 4.
However, such copolymers have monoacrylamide contents which, although extremely low, could result in making them impossible to use in cosmetics in the near future, following changes in the European legislation on hazardous substances.
The Applicant has thus been concerned with the synthesis and development of polymers that thicken, even at acidic pH, in the form of an inverted latex, without using monoacrylamide.
SUMMARY OF THE INVENTION
One subject of the invention is a composition comprising an oil phase, an aqueous phase, at least one emulsifier of water-in-oil (W/O) type, at least one emulsifier of oil-in-water (O/W) type, characterized in that the composition is an inverted latex comprising from 20% to 60% by weight, and preferably from 25% to 45% by weight, of a branched or crosslinked anionic polyelectrolyte based on at least one monomer possessing a strongly acidic function, copolymerized either with at least one monomer possessing a weakly acidic function or with at least one neutral monomer.
The expression “emulsifier of the water-in-oil type” is understood to denote emulsifiers having an HLB value that is low enough to give water-in-oil emulsions, such as the surfactant polymers sold under the name Hypermer™ or such as sorbitan extracts, for instance sorbitan monooleate sold by the company SEPPIC under the tradename Montane 80™, or sorbitan isostearate sold by SEPPIC under the name Montane 70™.
The expression “emulsifier of the oil-in-water type” is understood to denote emulsifiers having an HLB value that is high enough to give oil-in-water emulsions, such as ethoxylated sorbitan esters, for instance sorbitan oleate ethoxylated with 20 mol of ethylene oxide, sold by SEPPIC under the name MONTANOX 80™.
The term branched polymer is understood to denote a non-linear polymer which has pendant chains so as to obtain, when this polymer is dissolved in water, a high degree of entangling leading to very high low-gradient viscosities.
The term crosslinked polymer is understood to denote a non-linear polymer in the form of a three-dimensional network which is insoluble in water but swellable in water and thus leading to the production of a chemical gel.
The composition according to the invention can contain crosslinked units and/or branched units.
The subject of the invention is, in particular, a composition as defined above, characterized in that the anionic polyelectrolyte is the result of a copolymerization of its precursor monomers, which is carried out at a pH below 4.
The subject of the invention is also a composition as defined above, characterized in that 30% to 90% of the monomer units which comprise the anionic polyelectrolyte have a strongly acidic function.
The strongly acidic function of the monomer containing it is, in particular, a sulphonic acid function or a phosphonic acid function, partially or totally salified. The monomer can be for instance, styrenesulfonic acid partially or totally salified. It is preferably 2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propanesulphonic acid partially or totally salified in the form of an alkali metal salt or an ammonium salt. The weakly acidic function of the monomer containing it is, in particular, a carboxylic acid function, and the monomer is preferably chosen from acrylic acid, methacrylic acid, itaconic acid and maleic acid. The neutral monomer is chosen in particular from 2-hydroxyethyl acrylate, 2,3-dihydroxypropyl acrylate, 2-hydroxyethyl methacrylate and 2,3-dihydroxypropyl methacrylate, or an ethoxylated derivative, with a molecular weight between 400 and 1000, of each of these esters.
According to a specific aspect of the present invention, it relates to 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, characterized in that the said composition is a reverse latex comprising from 20% to 60% by weight, and preferably from 25% to 45% by weight, of a branched or crosslinked, anionic polyelectrolyte based on partially or totally salified 2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid, copolymerized with 2-hydroxyethyl acrylate, more particularly, a composition as defined above, characterized in that 30% to 90%, preferably 50% to 90%, in molar proportions, of the monomer units comprised by the anionic polyelectrolyte is 2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid (MPSA) partially or totally salified, and in particular a composition as defined above, for which the anionic polyelectrolyte contains, in molar proportions, from 60% to 90% of sodium salt or of ammonium salt of 2-methyl-2[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid and from 10% to 40% of 2-hydroxyethyl acrylate.
According to another specific aspect of the present invention, it relates to a composition as defined above, characterized in that the composition is a reverse latex comprising from 20% to 60% by weight, and preferably from 30% to 45% by weight, of a branched or crosslinked, anionic polyelectrolyte based on a 2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid, which is partially or totally salified in the form of sodium salt or of ammonium salt, copolymerized with acrylic acid, partially salified in the form of the sodium salt or of ammonium salt.
The subject of the invention is, more particularly, a composition as defined above, characterized in that the anionic polyelectrolyte is crosslinked and/or branched with a diethylenic or polyethylenic compound in a molar proportion, expressed relative to the monomers used, of from 0.005% to 1% and preferably from 0.01% to 0.2%, and more particularly from 0.01% to 0.1%, and preferably that for which the crosslinking agent and/or the branching agent is chosen from ethylene glycol dimethacrylate, sodium diallyl-oxyacetate, ethylene glycol diacrylate, diallylurea, trimethylolpropane triacrylate or methylene-bisacrylamide.
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 a specifi
Boiteux Jean-Pierre
Mallo Paul
Tabacchi Guy
Bawa Raj
Berman Alysia
Societe d'Exploitation de Produits pour les Industries Chim
Young & Thompson
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