INVERSE LATEX FOR A COSMETIC COMPOSITION COMBINING EDDS AS A SEQUESTERING AGENT AND A POLYELECTROLYTE COMPRISING AMPS AND ACRYLAMIDE

Abstract

Disclosed is a self-invertible inverse latex having an aqueous phase, including: a) a cross-linked anionic polyelectrolyte (P) including: - at least one monomer unit derived from 2-methyl-2-[(1-oxo-2-propenyl)amino] 1-propanesulfonic acid in the form of a free or partially or totally salified acid; - at least one monomer unit derived from at least one monomer selected from the elements of the group consisting of acrylamide, N,N-dimethylacrylamide, methacrylamide, N-isopropylacrylamide, N-tert-butylacrylamide; and - at least one monomer unit derived from a polyethylenic cross-linking monomer (AR); b) ethylenediamine disuccinic acid in the form of trisodium salt.

Claims

1. A self-invertible inverse latex comprising an aqueous phase comprising: a) a crosslinked anionic polyelectrolyte (P) consisting of: at least one monomer unit derived from 2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid in free acid form or partially or totally salified form; at least one monomer unit derived from at least one monomer chosen from the elements of the group consisting of acrylamide, N,N-dimethylacrylamide, methacrylamide, N-isopropylacrylamide, and N-(tert-butyl)acrylamide; and at least one monomer unit derived from a polyethylenic crosslinking monomer (AR); b) ethylenediaminedisuccinic acid in trisodium salt form.

2. The inverse latex as claimed in claim 1, wherein the aqueous phase comprises at least 0.01 mol% of ethylenediaminedisuccinic acid in trisodium salt form.

3. The inverse latex as claimed in claim 1, wherein the polyethylenic crosslinking monomer (AR) is chosen from methylenebis(acrylamide), ethylene glycol dimethacrylate, diethylene glycol diacrylate, ethylene glycol diacrylate, diallylurea, triallylamine, trimethylolpropane triacrylate, diallyloxyacetic acid or a salt thereof, or a mixture of these compounds.

4. The inverse latex as claimed in claim 1, wherein the crosslinking monomer (AR) is methylenebis(acrylamide) or triallylamine.

5. The inverse latex as claimed in claim 1, wherein the crosslinked anionic polyelectrolyte comprises, for 100 mol%: a proportion between 20% and 90% of the monomer unit derived from 2-methyl-2-[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid in free acid form or partially or totally salified form; a proportion of between 10% and 80% of the monomer unit derived from at least one monomer chosen from the elements of the group consisting of acrylamide, N,N-dimethylacrylamide, methacrylamide, N-isopropylacrylamide, and N-(tert-butyl)acrylamide, and a proportion of greater than 0 mol% and less than or equal to 1 mol% of monomer units derived from at least one polyethylenic crosslinking monomer (AR).

6. A process for preparing an inverse latex as defined in claim 1, comprising the following steps: a) preparing the aqueous phase, b) preparing an organic phase comprising at least one oil and an emulsifying surfactant system (S.sub.1) of water-in-oil type, c) mixing the aqueous phase and the organic phase prepared in steps a) and b) and emulsifying so as to form an emulsion, d) inerting the emulsion with nitrogen, e) initiating the polymerization reaction by introducing a free-radical initiator into the inerted emulsion, and f) introducing into the reaction medium resulting from step e) an emulsifying surfactant system (S.sub.2) of oil-in-water type at a temperature between 30° C. and 60° C.

7. The process as claimed in claim 6, wherein, in step e), the radical initiator is a redox pair which generates hydrogen sulfite (HSO.sub.3.sup.-) ions.

8. The process as claimed in claim 6, wherein, in step e), a polymerization coinitiator is introduced into the inerted emulsion.

9. The process as claimed in claim 6, wherein, in step a), the pH of the aqueous phase is adjusted between 3.0 and 7.0.

10. The process as claimed in claim 6, wherein the reaction medium derived from step e) is concentrated by distillation before carrying out step f).

11. The process as claimed in claim 6, wherein the reaction medium derived from step e) or f) is spray-dried.

12. A thickening and/or emulsifying and/or stabilizing agent for a topical cosmetic composition comprising the inverse latex of claim 1.

13. A topical cosmetic composition comprising, as thickening agent, per 100% of its total weight, between 0.1% and 10% by weight of said inverse latex as defined in claim 1.

14. A topical pharmaceutical composition comprising, as thickening agent, per 100% of its total weight, between 0.1% and 10% by weight of said inverse latex as defined in claim 1.

15. The process of claim 7, wherein the redox pair is the cumene hydroperoxide/sodium metabisulfite (Na2S2O5) pair.

16. The process of claim 7, wherein the redox pair is the cumene hydroperoxide/thionyl chloride (SOCl2) pair.

17. The process of claim 8, wherein the polymerization coinitiator is azobis(isobutyronitrile).

18. The inverse latex as claimed in claim 2, wherein the polyethylenic crosslinking monomer (AR) is chosen from methylenebis(acrylamide), ethylene glycol dimethacrylate, diethylene glycol diacrylate, ethylene glycol diacrylate, diallylurea, triallylamine, trimethylolpropane triacrylate, diallyloxyacetic acid or a salt thereof, or a mixture of these compounds.

19. The inverse latex as claimed in claim 2, wherein the crosslinking monomer (AR) is methylenebis(acrylamide) or triallylamine.

20. The inverse latex as claimed in claim 3, wherein the crosslinking monomer (AR) is methylenebis(acrylamide) or triallylamine.

Description

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0113] The following example illustrates the invention , without, however, limiting it.

1- Examples

1.1 Preparation of an Inverse Latex (LI.SUB.1.) Comprising a Crosslinked Copolymer of the Sodium Salt of 2-methyl-[(1-oxo-2-propenyl)amino]-1-propanesulfonic Acid and of Acrylamide Containing Ethylenediaminedisuccinic Acid in Trisodium Salt Form as Sequestering Agent

[0114] The following are charged to a beaker, with stirring: [0115] 272 g of a commercial solution containing 55% of sodium salt of 2-methyl-[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid [0116] 255 g of a solution containing 50% of acrylamide [0117] 115 g of 2-methyl-[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid [0118] 0.115 g of methylenebisacrylamide [0119] 0.62 g of a commercial solution of ethylenediaminedisuccinic acid in trisodium salt form [0120] 0.14 g of copper sulfate pentahydrate

[0121] The pH of the aqueous phase is adjusted to 6 with a 48% sodium hydroxide solution. The organic phase is prepared at the same time by mixing: [0122] 220 grams of isohexadecane [0123] 21 grams of Montane™ 80.sup.(1)

[0124] (1): Montane™80 is a Sorbitan Monooleate, an Emulsifying Surfactant of Water-In-Oil Type, Sold by SEPPIC.

[0125] The aqueous phase prepared above is gradually added to the oily phase and then dispersed using an Ultra Turrax™ rotor-stator sold by Ika™.

[0126] The emulsion obtained is then transferred to a jacketed reactor, and subjected to nitrogen bubbling in order to remove the oxygen. A solution containing 0.56% by weight of cumene hydroperoxide in 5 ml of isohexadecane is introduced and the emulsion is kept stirring for 5 minutes of homogenization at ambient temperature.

[0127] The polymerization reaction is initiated by adding 15 ml of an aqueous solution containing 0.2% of sodium metabisulfite. Once the polymerization reaction has finished, the reaction medium is heated at 85° C. for 1 h and then the whole mixture is cooled to approximately 35° C., then 50 g of Montanox™ 80 .sup.(2) are added to the preparation.

[0128] (2): Montanox™80 is a Polyoxyethylenated Derivative of a Sorbitan Monooleate, Used as a Surfactant of Oil-In-Water Type, Sold by SEPPIC.

[0129] The product obtained is referenced (LI.sub.1) and the results of its evaluations are presented in table 1.

1.2 Preparation of an Inverse Latex (LI.SUB.2.) Comprising a Crosslinked Copolymer of the Sodium Salt of 2-Methyl-[(1-oxo-2-propenyl)amino]-1-Propanesulfonic Acid and of Acrylamide Containing Sodium Diethylenetriaminepentaacetate as Sequestering Agent

[0130] The same protocol as 1.1 is implemented, but the 0.62 g of a commercial solution of ethylenediaminedisuccinic acid in trisodium salt form are replaced with 0.45 g of a solution of sodium diethylenetriamine pentaacetate (sold under the brand name Versenex™ 80).

[0131] The Product is referenced (LI.sub.2).

TABLE-US-00001 Test No. Sequestering agent (amount in mol ppm) Polymerization analyses Inhibition(min) exothermicity (°C) polymerization time (min) Latex viscosity 25° C. (mPa.s) (Brookfield RVT, Spindle 3 Speed 20) Viscosity of aqueous gel at 2% by weight, mPas.s (Brookfield RVT, Spindle 6 Speed 5) Viscosity of aqueous gel at 3% by weight + 0.1% NaCl, mPa.s (Brookfield RVT, Spindle 6 Speed 5) (LI.sub.2) Varenea™ 60 130 ppm 1 52.2 32 2500 97 000 9300 (LI.sub.1) Natriquest™ E30 200 ppm 0 52.8 30 3220 90 000 8640

Table 1: Properties of the copolymers obtained in examples 1.1 and 1.2

[0132] In conclusion, the tests for copolymerization of 2-methyl-[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid and of acrylamide show that, in the presence of copper cations, ethylenediaminedisuccinic acid trisodium salt exhibits an efficiency similar to sodium diethylenetriaminepentaacetate.

[0133] In each of the tests, the polymerization exhibits similar characteristics: duration of inhibition, of polymerization and exothermicity. The self invertible inverse latexes obtained under these conditions have equivalent thickening properties in water and in the presence of electrolytes.