Stable emulsions of polymer-shell drops

Abstract

An emulsion comprising a continuous aqueous phase and a dispersed fatty phase in the form of drops, or conversely, wherein the drops comprise a shell formed of at least one anionic polymer comprising at least one carboxylic acid function and at least one cationic polymer comprising at least two amine functional groups, wherein the quantity of amine functional groups provided by the cationic polymer in the fatty phase is between 0.2 μmol and 10.5 μmol per gram of fatty phase.

Claims

1. Emulsion comprising a continuous aqueous phase comprising an anionic polymer comprising at least one carboxylic acid group, and a dispersed fatty phase comprising a cationic polymer comprising at least two amine groups, and (i) wherein the fatty phase is in a form of drops surrounded by a shell formed of the anionic polymer comprising at least one carboxylic acid group and the cationic polymer comprising at least two amine groups; and (ii) wherein the total quantity of amine groups provided by the cationic polymer in the fatty phase is between 0.2 μmol and 7.0 μmol per gram of the fatty phase; and (iii) wherein said emulsion is kinetically stable at 25-50° C. for up to three months.

2. The emulsion according to claim 1, wherein the emulsion is an oil-in-water emulsion.

3. The emulsion of claim 1, wherein the cationic polymer is a silicone polymer modified with a primary, secondary or tertiary amine groups.

4. The emulsion of claim 1, wherein the cationic polymer has the following formula (I): ##STR00005## in which: R.sub.1, R.sub.2 and R.sub.3, independently of each other, represent OH or CH.sub.3; R.sub.4 represents a group —CH.sub.2— or a group —X—NH— in which X is a divalent alkylene radical having 3 or 4 carbon atoms; x is an integer between 10 and 5000; y is an integer between 2 and 1000; and z is an integer between 0 and 10.

5. The emulsion of claim 4, wherein the cationic polymer has the following formula (I-1): ##STR00006## in which: R.sub.4 represents a group —CH.sub.2— or a group —X—NH— in which X is a divalent alkylene radical having 3 or 4 carbon atoms; x is an integer between 80 and 300; y is an integer between 5 and 20; and z is an integer between 0 and 1.

6. The emulsion of claim 1, wherein the quantity of amine groups present in the cationic polymer is between 0.01 mmol and 12.3 mmol per gram of the cationic polymer.

7. The emulsion of claim 1, wherein the fatty phase comprises from 0.01% to 10% by weight of the cationic polymer relative to the total weight of the fatty phase.

8. The emulsion of claim 1, wherein the anionic polymer is a carbomer or a crosslinked copolymer acrylates/C.sub.10-30 alkyl acrylate.

9. The emulsion of claim 1, wherein the emulsion comprises from 0.01% to 5% by weight of anionic polymer relative to the total weight of the emulsion.

10. The emulsion of claim 2, comprising from 0.0001% to 50% by weight of oil(s) relative to the total weight of the emulsion.

11. The emulsion of claim 1, further comprising at least one active agent selected from the group consisting of hydrating agents, healing agents, depigmenting agents, UV filters, desquamating agents, antioxidants, stimulating active agents for the synthesis of dermal macromolecular agents, stimulating active agents for the synthesis of epidermal macromolecular agents, dermodecontracting agents, anti-perspirant agents, anti-aging agents, perfuming agents, and mixtures thereof.

12. A cosmetic composition comprising the emulsion of claim 1.

13. A non-therapeutic method for a cosmetic treatment of a keratin material, comprising at least one step of applying to the keratin material the emulsion of claim 1.

14. A non-therapeutic method for a cosmetic treatment of a keratin material, comprising at least one step of applying to the keratin material the composition of claim 12.

15. The emulsion according to claim 1, wherein the total quantity amine groups provided by the cationic polymer in the fatty phase is calculated according to the formula:
Q=A×T where: Q represents the quantity of amine groups provided by the cationic polymer in the fatty phase (in μmol/g), A represents the weight percentage of the cationic polymer in the fatty phase, and T represents the proportion of amine groups carried by the cationic polymer (in μmol/g of cationic polymer).

16. The emulsion according to claim 1, wherein the drops have a diameter of less than 2 mm after storage at 25-50° C. for up to three months.

17. The emulsion according to claim 1, wherein said emulsion is kinetically stable at 25-5O ° C. for up to three months, and wherein said emulsion undergoes less coalescence than an emulsion comprising a total quantity of amine groups provided by the cationic polymer in the fatty phase that is greater than 7.0 μmol per gram of the fatty phase.

Description

(1) The results obtained at room temperature and 50° C. are shown in FIGS. 1 and 2.

(2) FIG. 1 describes the evolution of the coalescence (average of the notes obtained during the 3 months of follow-up) as a function of the quantity of amine functions provided by the amodimethicone (AM1, AM2 or AM3) in the fatty phase at room temperature.

(3) FIG. 2 describes the evolution of coalescence (mean of the scores obtained during the 3 months of follow-up) as a function of the quantity of amine functions provided by amodimethicone (AM1, AM2 or AM3) in the fatty phase at 50° C.

(4) In FIGS. 1 and 2, the curves of the 3 amodimethicones tested (AM1, AM2 and AM3) have the same evolution. These amodimethicones therefore have a similar behavior in the face of coalescence. Thus, it may be deduced that the structural differences of amodimethicones do not seem to impact coalescence. On the other hand, it was observed that the coalescence is a function of the quantity of amine functions (provided by the amodimethicone) in the fatty phase.

(5) Improved coalescences, i.e. low, or even zero, were observed in particular for dispersions whose quantity in amine functions (provided by amodimethicone) in the fatty phase is between 0.2 μmol and 7 μmol per gram of fatty phase (dispersions according to the invention), whatever the nature of the amodimethicone. These results advantageously demonstrate the stability of the emulsions according to the invention.

(6) It has been shown that the coalescence is even lower, or even zero, for emulsions whose quantity in amine functions (provided by the amodimethicone) in the fatty phase is less than 7 μmol, or even less than 5 μmol, and in particular less than 3 μmol, per gram of fatty phase.

(7) In particular, low or no coalescences were observed for dispersions whose quantity in amine functions (provided by amodimethicone) in the fatty phase is between 0.2 μmol and 5 μmol per gram of fatty phase, preferably between 0.2 μmol and 4 μmol. The best results are observed for dispersions whose quantity in amine functions (provided by amodimethicone) in the fatty phase is between 0.2 μmol and 3 μmol per gram of fatty phase, and especially between 0.2 μmol and 2 μmol.

(8) Above 7 μmol per gram of fatty phase, the results show that coalescence is induced more significantly. This increase is even more marked for samples placed at 50° C. Thus, when the quantity of amine functions provided by the amodimethicone in the fatty phase is greater than 7 μmol, the dispersions have a greater coalescence, and therefore a lower stability compared to the dispersions according to the invention.

Example 3: Mechanical Strength Test

(9) In the context of this example, the mechanical strength of the emulsions described in Example 1 above was evaluated using the following protocol: a glass pot of 4.5 cm in diameter and 7 cm in height containing the dispersions to a height of 50 mL, was positioned on a modular roller shaker (R2P-Wheaton). By imposing a rotation of the pot, the drops are subjected to a combination of deformations and relaxations. This offers both a simple shear but also the phenomena of compression and expansion.

(10) The samples were subjected to a first cycle of 3 minutes at 6 rpm and then to a second cycle at 30 rpm of the same duration. After each cycle, a visual evaluation was performed on the samples with the following rating system: from 0 for no fragmentation, to 4 for a very large drop fragmentation. This test was performed 1 month after the production of the drops.

(11) This rolling test made it possible to evaluate the shear strength of emulsion drops.

(12) The results are shown in FIGS. 3 and 4 below.

(13) FIG. 3 describes the evaluation of the mechanical resistance (visual rating) as a function of the quantity of amine functions provided by the amodimethicone (AM1, AM2 or AM3) in the fatty phase (in μmol per gram of fatty phase) at 6 rpm for 3 minutes.

(14) FIG. 4 describes the evaluation of the mechanical resistance (visual rating) as a function of the quantity of amine functions provided by amodimethicone (AM1, AM2 or AM3) in the fatty phase (in μmol per gram of fatty phase) at 30 rpm for 3 minutes.

(15) The results showed that, whatever the nature of the amodimethicone studied, the observed behavior is similar.

(16) It has been shown that for quantities of amine functions provided by the amodimethicone, in the fatty phase, are too low, typically less than 0.2 μmol, wherein the mechanical strength of the drops is very low (a significant fragmentation is observed). Significant fragmentation of the drops is also observed for comparative dispersions comprising high quantities of amine functions, for example greater than 10.5 μmol, in the fatty phase.

(17) Between these two extremes, an area was advantageously observed where the mechanical strength of the drops is satisfactory.

(18) Despite good stability under static conditions, the dispersions obtained in the absence of amine have zero mechanical strength. Thus under flow, the stability of this sample is not acceptable. In an industrialization context, the emulsion is subjected to flow constraints which must not cause fragmentation of the drops.

(19) However, it has been observed that the mechanical strength is improved by increasing the quantity of amine functions (provided by the amodimethicone) in the fatty phase.

(20) Thus, the emulsions according to the invention comprising an quantity of amine functions provided by the amodimethicone in the fatty phase, of between 0.2 μmol and 10.5 μmol per gram of fatty phase, advantageously offer an improved resistance to fragmentation of the drops, which reflects a high mechanical strength for these emulsions.

(21) This resistance to fragmentation of the drops is further improved for emulsions according to the invention comprising a quantity of amine functions provided by the amodimethicone in the fatty phase, of between 0.3 μmol and 7 μmol, preferably between 0.4 μmol and 5 μmol, and better still between 0.8 μmol and 2 μmol, per gram of fatty phase

Example 4: Sparkling Balm for the Body

(22) Preparation Protocol (Non-Microfluidic Method)

(23) In a beaker (1), weigh the osmosis water and the chelating agent(s) (in particular EDETA BD).

(24) Place the beaker (1) under mechanical stirring with a deflocculating blade until homogenization.

(25) Continue the stirring and add the anionic polymer(s) (especially the carbomer) in the beaker (1).

(26) Leave the mixture obtained at rest for about 20 minutes (to ensure the hydration of the anionic polymer), then resume stirring until homogenization.

(27) Weigh and add in the beaker (1) the gelling agent(s) of aqueous phase (including Aristoflex AVC, Sepimax zen).

(28) If necessary, weigh and add 10% sodium hydroxide solution.

(29) Stir until homogenization.

(30) In another beaker (2), weigh the glycerin, if necessary with at least one gelling agent of aqueous phase.

(31) Mix with a spatula to obtain a homogenous premix.

(32) Add the premix (2) to the beaker (1).

(33) When the solution obtained in the beaker (1) is homogeneous, heat the solution to 67° C.

(34) In another beaker (3), weigh the cationic polymer (especially amodimethicone) and the isononyl isononanoate.

(35) With magnetic stirring, heat the solution to 67° C. for about 5 minutes until homogenized.

(36) Then, weigh any additional oils and/or solid fats still in the beaker (3).

(37) Put everything under magnetic stirring, and heat to 67° C. for 10 minutes until homogenization.

(38) When the solutions in the beakers (1) and (3) are at the given temperature (i.e. 67° C.), subject the solution of the beaker (1) to strong mechanical agitation.

(39) Obtaining the emulsion then consists in adding the solution of the beaker (3) in the beaker (1) under this strong mechanical stirring.

(40) Continue to stir for 15 to 20 minutes, then cool to 40° C. to 35° C.

(41) In another beaker (4), add the preservative(s), especially phenoxyethanol (i.e. Microcare PE) and/or pentylene glycol (i.e. Microcare Emollient PTG).

(42) Mix with a spatula to obtain a homogenous premix.

(43) At 35° C., add the premix of the beaker (4) to the beaker (1).

(44) When present, weigh and add the denatured alcohol (especially superfine 99 denat ethyl alcohol) into the beaker (1).

(45) Leave to homogenize.

(46) Weigh and add the cosmetic active and/or perfumes and/or coloring agents successively in the beaker (1).

(47) Leave to homogenize.

(48) Weigh and add a 10% soda solution in the beaker (1).

(49) A body balm is prepared according to the protocol described above and comprises the following ingredients:

(50) TABLE-US-00005 Commercial designation Supplier INCI % Osmosis water Capsum AQUA 52.460% EDETA BD BASF DISODIUM EDTA 0.030% Microcare PE Thor PHENOXYETHANOL, AQUA 0.800% Microcare Emollient PTG Thor PENTYLENE GLYCOL, AQUA 2.000% Tego Carbomer 340 FD Evonik CARBOMER 0.192% Carbopol Ultrez 21 polymer Lubrizol 0.408% Sepimax Zen Seppic POLYACRYLATE 0.250% CROSSPOLYMER-6 Glycerine codex (99%) Interchimie GLYCERIN 20.000% Zemea Propanediol Dupont Tate & Lyle PROPANEDIOL 5.000% Butylene glycol 1,3 Interchimie BUTYLENE GLYCOL 5.000% Solution soude 10% Panreac AQUA, SODIUM HYDROXYDE 0.100% Dub ININ Nusil ISONONYL ISONONANOATE 2.000% CAS-3131 Nusil AMODIMETHICONE 0.020% Dub PTB Stéarinerie Dubois PENTAERYTHRITYL 0.500% TETRABEHENATE Eutanol G 1.000% Lipex Shea Light AAK SHEA BUTTER ETHYL ESTERS 1.000% Plantec refined shea butter CRM International BUTYROSPERMUM PARKII 0.500% MOD Gattefossé 1.500% Lipocire A Gattefossé TRIGLYCERIDES C10-18 1.000% Floraesters 30 Floratech JOJOBA ESTERS 0.500% Lanette O OR BASF CETEARYL ALCOHOL 1.000% Dub VCl 10 Stéarinerie Dubois ISODECYL NEOPENTANOATE 1.000% Sensual Drop Givaudan FRAGRANCE 0.300% Sepimat SB Seppic METHYL MATHACRYLATE 2.000% CROSSPOLYMER Solution soude 10% Panreac AQUA, SODIUM HYDROXYDE 0.900% Prestige soft bronze Eckart 0.040% Colorona Sun Gold Merck 0.100% Sparkle MP-29 Sunshine spectral gold SunChemical 0.400%

Example 5: Anti-Aging Serum

(51) Anti-aging serum with the following ingredients was prepared.

(52) TABLE-US-00006 % w/w Name INCI name PHASES % w/w AQUEOUS PHASE GEL Osmosis water Water 86.56 78.70 Microcare PE Phenoxyethanol 0.88 0.80 Microcare Emollient Pentylene glycol 2.20 2.00 PTG Tego Carbomer 340FD Carbomer 0.27 0.25 Rhodicare T Xanthan gum 0.11 0.10 Phylcare Sodio Sodium hyaluronate 0.01 0.010 Yaluronato XS Glycerine codex (99%) Glycerin 4.40 4.00 Zemea Propanediol 5.50 5.00 EDETA BD Disodium EDTA 0.03 0.030 Solution 10% Sodium Aqua; sodium 0.04 0.038 Hydroxide Pellets PRS hydroxide codex Total 100.00 90.93 FATTY PHASE DUB ININ Isononyl Isononanoate 54.68 4.96 KF-96A-50CS (PDMS Dimethicone 44.68 4.06 50 cSt) Ionol CP BHT 0.45 0.040 (hydroxytoluene butyl) D&C Red N.sup.o17 K7007 CI 26100 0.0013 0.00012 Nusil CAS 3131 Amodimethicone 0.18 0.020 Total 100.00 9.08 Total 100.00

(53) The final composition comprises translucent pink fatty phase drops dispersed in a colorless aqueous gel.