COSMETIC COMPOSITION FOR HAIR

Abstract

The invention relates to an aqueous cosmetic composition for care and maintenance of the hair comprising at least one setting resin, said resin comprising at least 20 mol % of a monomer unit of methacrylic acid and/or one of its salts; and optionally at least one monomer unit of acrylic acid and/or maleic anhydride, and/or one of their salts, the resin having a weight-average molecular weight greater than or equal to 20,000 g/mol. The invention also relates to the use of the setting resin for improving the resistance to humidity of these cosmetic compositions.

Claims

1. An aqueous cosmetic composition for hair care comprising at least one setting resin, said resin comprising: at least 30 mol % of monomer units of methacrylic acid and/or a salts thereof; at least 10 mol % of monomer units of acrylic acid and/or maleic acid and/or itaconic acid, and/or a salt thereof; the resin being water-soluble and having a weight-average molecular weight of 20,000 gm/mol or more.

2. The composition according to claim 1, wherein the resin comprises less than 80 mol % of the monomer units of methacrylic acid and/or a salt thereof.

3. The composition according to claim 1, wherein the resin comprises at least 20 mol % of the monomer units of acrylic acid and/or maleic acid and/or itaconic acid and/or a salt thereof.

4. The composition according to claim 1, wherein the resin comprises less than 70 mol % of the monomer units of acrylic acid and/or maleic acid and/or itaconic acid and/or a salt thereof.

5. The composition according to claim 1, wherein the resin is a copolymer of methacrylic acid and acrylic acid and/or their salts.

6. The composition according to claim 1, wherein the resin has a weight-average molecular weight greater than or equal to 60,000 g/mol.

7. The composition according to claim 1, wherein the resin has a weight-average molecular weight greater than or equal to 2,000,000 g/mol.

8. The composition according to claim 1, wherein the resin represents 0.05 to 10% by weight, based on the weight of the composition.

9. The composition according to claim 1, wherein the composition comprises: water; from 0.05 to 10% by weight of the setting resin; and a thickening agent.

10. The composition according to claim 1, wherein the composition comprises a thickening agent consisting of a cross-linked polyacrylic acid.

11. The composition according to claim 1, wherein the composition is in gel form.

12. The composition according to claim 1, wherein the composition has a transmittance value greater than 85%, the transmittance measurement being carried out at 420 nm, with an optical path of 10 mm, at 25° C., for a solution comprising 2.4 g/L of resin in water.

13. A method for improving resistance to humidity of an aqueous cosmetic composition, said method comprising adding to an aqueous preparation a setting resin comprising: at least 30 mol % of monomer units of methacrylic acid and/or a salt thereof; at least 10 mol % of monomer units of acrylic acid and/or maleic acid and/or itaconic acid, and/or a salt thereof; the resin being water-soluble and having a weight-average molecular weight of 20,000 g/mol or more.

14. A setting resin for an aqueous cosmetic composition for hair care, the resin comprising: at least 30 mol % of monomer units of methacrylic acid and/or a salt thereof; at least 10 mol % of monomer units of acrylic acid and/or maleic acid and/or itaconic acid, and/or a salt thereof; the resin being water-soluble and having a weight-average molecular weight of 20,000 gm/mol or more.

15. The composition according to claim 1, wherein the resin comprises: at least 30 mol % and less than 80 mol % of the monomer units of methacrylic acid and/or a salt thereof; at least 20 mol % and less than 70 mol % of the monomer units of acrylic acid and/or maleic acid and/or itaconic acid and/or a salt thereof; and

16. The composition according to claim 15, wherein the resin is a copolymer of methacrylic acid and acrylic acid and/or their salts.

17. The composition according to claim 15, wherein the resin has a weight-average molecular weight greater than or equal to 60,000 g/mol.

18. The composition according to claim 16, wherein the resin represents 0.05 to 10% by weight, based on the weight of the composition.

19. The composition according to claim 16, wherein the composition is in gel form and comprises: water; a thickening agent; and from 0.05 to 10% by weight of the setting resin, said setting resin having a weight-average molecular weight greater than or equal to 60,000 g/mol.

20. The composition according to claim 19, wherein the resin has a weight-average molecular weight greater than or equal to 2,000,000 g/mol.

Description

FIGURES

[0072] FIG. 1 illustrates the change in the percentage of curl retention over time of the compositions containing a setting resin.

EXAMPLES OF EMBODIMENTS OF THE INVENTION

1/Synthesis of Setting Resins

[0073] 203.0 gm of water and 50 mg of sodium hypophosphite are introduced into a jacketed reactor equipped with a mechanical stirrer with a half-moon paddle, a refrigerant, and a temperature probe. The medium is heated to 83° C. When the temperature is reached, a solution containing acrylic acid (AA) and methacrylic acid (AMA) or hydroxypropyl acrylate (HPA) co-monomer is added over a period of 120 minutes. The quantities of AA and AMA or HPA are shown in Table 1.

[0074] In parallel, a 10.0% by weight sodium persulfate solution is added over a period of 135 minutes. When pouring of the sodium persulfate solution has ended, the medium is cooled to 60° C., and 156.8 gm of water is added to the medium. The pH is adjusted between 2.2 and 3.0 then the medium is stirred for an additional hour. The product is then filtered at 300 μm.

[0075] Polymeric solutions corresponding to Examples 2 to 6 are obtained, the compositions and the average molecular weights by weight (Mw) of which are detailed in Table 1. The resin of the composition of Example 1, for its part, contains only acrylic acid monomers.

TABLE-US-00001 TABLE 1 Compositions and Molecular Weight of Setting Resins Polymer composition (mol %) Mw AA AMA HPA (gm/mol) Example 1 (Comparative) 100 191,000 Example 2 (Comparative) 91.5 8.5 172,000 Example 3 (Invention) 55 45 152,000 Example 4 (Invention) 29 71 179,000 Example 5 (Comparative) 55 45 15,900 Example 6 (Comparative) 55 45 326,000

2/Manufacture of Transparent Aqueous Cosmetic Compositions for Hair Care

[0076] The resins corresponding to Examples 1 to 6 are incorporated into the gel formulation described in Table 2. We thus obtain compositions C′1 to C′6 containing respectively setting resins 1 to 6.

TABLE-US-00002 TABLE 2 Hair Gel Composition % by Weight Water Qs 100 Carbomer (Flogel FG 1000) 2.00 Polymer of Examples 1 to 7 0.24 Glycerine 1 EDTA 0.03 TEA Qs pH 6.5 Perfume 0.2

[0077] Qs 100=sufficient quantity to reach 100%

[0078] EDTA=ethylenediaminetetraacetic acid

[0079] TEA=Triethanolamine

[0080] Qs pH 6.5=sufficient quantity to reach a pH of 6.5

[0081] The clarity of the gels is determined by measuring the transmittance of light on a Hach Lange DR 600 spectrophotometer. These measurements were carried out at 420 nm in 1.5 mL PS cuvettes, at 25° C., for a solution comprising 2.4 gm/L of resin in water.

[0082] The viscosity of the gels is determined at 23° C. with a Brookfield RVT viscometer at a speed of 20 revolutions/min. Those skilled in the art know how to choose the modulus as a function of the viscosity of the gels. In this case, and taking into account the composition of the gel and the desired texture, module 7 is used.

[0083] The results are reported in Table 3.

TABLE-US-00003 TABLE 3 Viscosity and Clarity of the Styling Gels Gel Composition Viscosity CPS (20 tpm) Clarity % T (420 nm) C′1 (Comparative) 54.000 89 C′2 (Comparative) 56.000 91 C′3 (Invention) 58.000 92 C′4 (Invention) 64.000 91 C′5 (Comparative) 70.000 97 C′6 (Comparative) 61.000 88

[0084] The gels of compositions C′1 to C′6 obtained are all transparent because they have a clarity greater than 85% T. Their viscosity and their rheological property are very good.

3/Resistance to Humidity of the Setting Resins

[0085] The resins' resistance to humidity was evaluated by a “curl retention” test.

[0086] The protocol is as follows: 3.1 gm of resin is added to 87.5 gm of hydroalcoholic water/ethanol solution (37/63). We thus obtain the compositions C′1 to C′6 containing the resins of Examples 1 to 6, respectively.

[0087] A strand of European-type hair is immersed in the hydroalcoholic resin solution, and the excess solution is removed by passing the strand of hair between two fingers over its entire length. The hair strand is then combed once and rolled up on a curler.

[0088] The strands are then placed on the curler for 24 hours at 23° C. and 50% relative humidity. The strands are unrolled and placed in a humidity-controlled oven at 90% at 25° C. The length of the strand at to is used as a reference (Li) for the calculation of the percentage of curl hold (% TB), also known as the percentage of curl retention (% CR). The length of the strands is measured at different time intervals (Lt).

[0089] The percentage of curl retention is calculated using the following ratio:

% TB=[(L−Lt)/(L−Li)]*100

with L=Length of the unrolled strand=19 cm.

[0090] We observe, in FIG. 1, that the compositions C′3 and C′4, respectively containing the resins of Examples 3 (45% mol AMA) and 4, (71% mol AMA), offer excellent resistance to humidity, although greater than those obtained with compositions C′1 and C′2, containing the resins of Examples 1 (0 mol % AMA) and 2 (8.5 mol % AMA). Composition C′2 exhibits poorer curl retention than composition C′1. This demonstrates that the incorporation of AMA in a resin is not the only parameter for increasing curl strength but that a minimum molar percentage of at least 30 AMA in the AA/AMA copolymer is necessary to obtain better curl retention.

[0091] We also observe from the results of compositions C′3 and C′4 in FIG. 1 that the increase in the amount of AMA in the copolymer makes it possible to obtain increased resistance to humidity. Furthermore, compositions C′5 and C′6 offer very poor resistance to humidity. The observation of curve C′6 compared to curve C′3 allows us to say that the substitution of AMA by HPA strongly degrades the resistance to humidity.

[0092] Observation of curve C′5 compared to curve C′3 makes it possible to demonstrate the importance that the molecular weight of the resin has on the resistance to humidity of the composition containing it. In fact, composition C′5 containing an AA/AMA 45/55 copolymer with a weight-average molecular weight of less than 20,000 gm/mol does not make it possible to increase curl retention. Finally, the strands prepared with compositions C′3 and C′4 according to the invention do not exhibit any stickiness and are easy to remove during washing, thus satisfying the desired criteria.

4/Examples 7 and 8

[0093] A methacrylic acid homopolymer (Example 7), i.e., containing 100 mol % of monomer units of methacrylic acid, is prepared according to the method described in the scientific publication “High Molecular Weight Poly(methacrylic acid) with Narrow Polydispersity by RAFT Polymerization”—Macromolecules, 2009, 42, pages 1494-1499. The polymer obtained corresponds to example 7. Another polymer is prepared according to the same method, except that 12 mol % of the methacrylic acid is replaced by 12 mol % of acrylic acid. The polymer obtained corresponds to Example 8. The polymer of Example 7 has such high viscosity that it cannot be used by formulators of cosmetic compositions due to the fact that it is too difficult to handle. Nor does a dilution test to reduce the viscosity lead to a product that is satisfactory for the user because of stability problems. Its properties are therefore not evaluated.

[0094] The polymer of Example 8 is able to be handled. A hair gel composition C′8 is made with the polymer of Example 8 according to the formulation of Table 2. The viscosity of the gel is 52,000 CPS, and the clarity is 91%. The same resistance to humidity test as in part 3/is carried out, and the curl hold at 300 minutes is 93%, which is very satisfactory and demonstrates the technical effect of the polymers of the invention.

5/Examples 9 to 14

[0095] The polymers of lines 2, 5, and 8 of Table 1 of document EP1402877 are produced. They are noted as examples 9, 11, and 13, respectively. A polymer 10 is made as polymer 9, in which 10 mol % ethyl acrylate is replaced by 10 mol % acrylic acid. A polymer 12 is made as polymer 11, in which 25 mol % ethyl acrylate is replaced by 25 mol % methacrylic acid. A polymer 14 is made, such as polymer 13, in which 25 mol % of methyl acrylate is replaced by 25 mol % of methacrylic acid.

[0096] Table 4 summarizes the composition of polymers 9 to 14.

TABLE-US-00004 TABLE 4 Composition of Polymers 9 to 14 AA AMA EA MA Lipol 1 DAP DDM Example 9 7.13 30 62 0.87 0.2 0.1 (Comparative) Example 10 15 30 52 0.87 0.2 0.1 (Invention) Example 11 27.76 11.58 59.82 0.84 0.2 0.1 (Comparative) Example 12 27.76 36.58 34.82 0.84 0.2 0.1 (Invention) Example 13 25.29 10.55 63.4 0.76 0.2 0.1 (Comparative) Example 14 25.29 35.55 38.4 0.76 0.2 0.1 (Invention)

[0097] The values of acrylic acid (AA), methacrylic acid (AMA), ethyl acrylate (EA), methyl acrylate (MA), and Lipol 1 are expressed in mol %. The values of diallyl phthalate (DAP) and n-dodecyl mercaptan (DDM) are expressed as mass %. The molecular weight of Lipol 1 is 1188 g/mol.

[0098] Lipol 1 is a lipophilically modified monomer having a linear saturated alkyl group of 18 carbon atoms connected via 20 residues of ethylene oxide to a methacryloyl group.

[0099] The polymers 9 to 14 are used in the hair gel composition of Table 2, and the gel compositions obtained are noted respectively as C′9 to C′14. The viscosity of the gels and their clarity were measured according to the same methods previously described. The results are reported in Table 5.

TABLE-US-00005 TABLE 5 Viscosity and Clarity of Styling Gels C′9 to C′14. Gel Composition Viscosity CPS (20 tpm) Clarity % T (420 nm) C′9 (Comparative) 67,000 84 C′10 (Invention) 70,000 87 C′11 (Comparative) 51,000 87 C′12 (Invention) 62,000 91 C′13 (Comparative) 56,000 89 C′14 (Invention) 63,000 93

[0100] The same resistance to humidity test as in part 3/is carried out, and the results of curl hold at 300 minutes are given in Table 6.

TABLE-US-00006 TABLE 6 Curl Hold of Compositions C′9 to C′14 Gel Composition Curl Hold in % C′9 (Comparative) 76 C′10 (Invention) 84 C′11 (Comparative) 65 C′12 (Invention) 85 C′13 (Comparative) 67 C′14 (Invention) 88

[0101] Increasing the proportion of acrylic acid from 7.13 mol % to 15 mol % in Example 9 results in more than a 10% improvement in curl hold. Increasing the proportion of acrylic acid from 11.58 mol % to 36.58 mol % in Example 11 results in more than a 30% improvement in curl hold. Increasing the proportion of acrylic acid from 10.55 mol % to 30.55 mol % in Example 13 results in more than a 31% improvement in curl hold.

[0102] These results make it possible to demonstrate the better performance of the polymers according to the invention, in particular, compared to those of the prior art.