Ampholytic polymers having a thermosensitive character

Abstract

A comb copolymer with a polymer backbone having grafted lateral macromonomer segments, the method of preparing, and the use thereof as a thickener in cosmetics. The polymer backbone is more than 55% and up to 90% molar ATBS, between 1% and 20% molar cationic monomer or monomer of formula (I): CH.sub.2C(R.sub.1)C(O)Y(CH.sub.2)m-N(R.sub.2) (R.sub.3), where m is between 1 and 4, Y is O or NH, R1 is H or CH.sub.2, and R.sub.2 and R.sub.3 are each a methyl or ethyl radical, and optionally 0.005% to 1% molar of at least one cross-linking monomer with at least two CC bonds. The lateral macromonomer segments are polymerized from 9% to 30% molar of N-alkyl acrylamide or N,N-dialkyl acrylamide of formula (II): CH.sub.2C(R.sub.4)C(O)N(R.sub.5) (R.sub.6), where R.sub.4 is H or CH.sub.2 and R.sub.5 and R.sub.6 are H or a C.sub.1 to C.sub.3 alkyl radical, with at least one of R.sub.5 or R.sub.6 not being H.

Claims

1. A comb copolymer consisting of a polymer backbone to which macromonomeric side segments are grafted, wherein said polymer backbone consists, for 100 mol % of constituent monomer units of said comb copolymer: of more than 55 mol %, up to 90 mol % of monomer units resulting from 2-methyl 2-[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid (hereinafter denoted ATBS), which is free, partially salified or completely salified; of 1 mol % to 20 mol % of monomeric units resulting from a monomer of dimethylaminoethyl methacrylate or N-[3-(dimethylamino)propyl]acrylamide; optionally of 0.005 mol % to 1 mol % of monomer units resulting from at least one crosslinking monomer comprising at least two carbon-carbon double bonds, and said macromonomeric side segments result, for 100 mol % constituent of said comb copolymer, from the polymerization of 9 mol % to 30 mol % of an N-alkylacrylamide selected from the group consisting of N-methylmethacrylamide, N-ethylmethacrylamide, N-propylmethacrylamide, N-isopropylmethacrylamide, N-(2-hydroxyethyl)methacrylamide, N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide, N-isopropylacrylamide, and N-(2-hydroxyethyl)acrylamide.

2. The comb copolymer as defined in claim 1, wherein the N-alkylacrylamide is N-isopropylacrylamide.

3. The comb copolymer as defined in claim 1, wherein the monomer units resulting from 2-methyl 2-[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid (hereinafter denoted ATBS) are 60 mol % to 80 mol % of the comb copolymer.

4. The comb copolymer as defined in claim 1, wherein the monomeric units resulting from a monomer of dimethylaminoethyl methacrylate or N-[3-(dimethylamino)propyl]acrylamide are 4 mol % to 15 mol % of the comb copolymer.

5. The comb copolymer as defined in claim 1, wherein the monomer units resulting from at least one crosslinking monomer comprising at least two carbon-carbon double bonds are 0.01 mol % to 0.5 mol % of the comb copolymer.

6. The comb copolymer as defined in claim 1, wherein the macromonomeric side segments result from the polymerization of 15 mol % to 25 mol % of said N-alkylacrylamide.

7. A process for preparing the comb copolymer as defined in claim 1, comprising the steps of: (a) reacting: an N-alkylacrylamide compound selected from the group consisting of N-methylmethacrylamide, N-ethylmethacrylamide, N-propylmethacrylamide, N-isopropylmethacrylamide, N-(2-hydroxyethyl)methacrylamide, N-methylacrylamide, N-ethylacrylamide, N-propylacrylamide, N-isopropylacrylamide, and N-(2-hydroxyethyl)acrylamide, said N-alkylacrylamide compound being defined according to formula (II):
CH.sub.2C(R.sub.2)C(O)N(R.sub.3)(R.sub.4)(II), in which, depending on said N-alkylacrylamide compound, R.sub.2 represents a hydrogen atom or a methyl group, R.sub.3 represents a hydrogen atom and R.sub.4 represents a linear or branched alkyl radical comprising from 1 to 3 carbon atoms, optionally substituted by a hydroxyl group, with a chain-limiting compound of formula (IVa):
HSR.sub.1NH.sub.2(IVa)
or of formula (IVb):
HSR.sub.1C(O)OH(IVb) in which formula (IVa) or (IVb) R.sub.1 represents a divalent radical comprising from 1 to 4 carbon atoms, in the presence of a polymerization initiator, in a tert-butanol/water mixture, in order to obtain a poly(N-alkylacrylamide) telomer of formula (Va):
H.sub.2NR.sub.1S{CH.sub.2C(R.sub.2)[C(O)N(R.sub.3)(R.sub.4)]}.sub.nH(Va)
or of formula (Vb):
HOC(O)R.sub.1S{CH.sub.2C(R.sub.2)[C(O)N(R.sub.3)(R.sub.4)]}.sub.nH(Vb), in which formula (Va) or (Vb) n represents an integer of greater than or equal to 2 and less than or equal to 100; optionally (b) isolating and/or drying of said telomer of formula (Va) or of formula (Vb) obtained in step (a); (c) reacting in tert-butanol of the telomer of formula (Va) or of formula (Vb) obtained in step (a), or optionally in step (b), with glycidyl methacrylate (VI) and in a (VI)/(IVa) or (VI)/(IVb) molar ratio of less than or equal to 10 and greater than or equal to 1, while maintaining the pH of the reaction medium at a value of greater than 10 and less than or equal to 13 in order to obtain, after adjustment of the pH to a value of greater than or equal to 7 and less than or equal to 9 a solution of the macromonomer of formula (VIIa):
CH.sub.2C(CH.sub.3)C(O)NHR.sub.1S{CH.sub.2C(R.sub.2)[C(O)N(R.sub.3)(R.sub.4)]}.sub.nH (VIIa); or of formula (VIIb):
CH.sub.2C(CH.sub.3)C(O)O(CO)R.sub.1S{CH.sub.2C(R.sub.2)[C(O)N(R.sub.3)(R.sub.4)]}.sub.nH (VIIb); optionally (d) isolating and/or drying of said macromonomer of formula (VIIa) or of formula (VIIb) obtained in step (c); (e) copolymerizing in tert-butanol of said macromonomer of formula (VIIa) or of formula (VIIb) resulting from step (c) or from optional step (d) with 2-acrylamido-2-methylpropanesulfonic acid and dimethylaminoethyl methacrylate or N-[3-(dimethylamino)propyl]acrylamide, and optionally with at least one crosslinking monomer comprising at least two carbon-carbon double bonds in the desired molar proportions, and, optionally (f) purifying the comb copolymer obtained in step (e).

8. A method for caring for and/or conditioning the hair, comprising applying an effective amount of a cosmetic or pharmaceutical composition comprising the comb copolymer as defined in claim 1.

9. A cosmetic or pharmaceutical composition, comprising, as thickening agent, an effective amount of the comb copolymer as defined in claim 1.

Description

Example 1 of Synthesis of the ATBS(NH4)/DMAPAM/NIPAM Copolymer Molar Ratio: 70.6/7.8/21.6

(1) (1) Preparation of a Poly(N-Isopropylacrylamide) Telomer

(2) 60 g of N-isopropylacrylamide (NIPAM) are dissolved at 25 C. in 75 g of a tert-butanol/water (50/50 by volume) mixture in a thermostatically controlled reactor, which is stirred for approximately 1 hour while flushing with nitrogen. 0.9 g of 2-aminoethanethiol hydrochloride (AET.HCl) is subsequently added. The polymerization is initiated by adding 1.33 g of dilauroyl peroxide, the temperature being brought to 60 C., and then the reaction mixture is left stirring for a further three and a half hours while flushing with nitrogen. 87 g of tert-butanol are subsequently added to result in a white and pasty final reaction mixture.

(3) (2) Preparation of the Macromonomer

(4) 0.5 g of a 48% by weight solution of sodium hydroxide in tert-butanol is added to the reaction medium obtained in stage (1) maintained at a temperature of 10 C., in order to bring the pH to approximately 12 during. 3.16 g of glycidyl methacrylate are then added and the reaction is left to take place for one hour. At the end of the reaction, approximately 1.3 g of 15% hydrochloric acid in water are added in order to lower the pH to a value of between 7 and 8.

(5) The solution obtained comprises 28.1% by weight of NIPAM macromonomer and 17% by weight of water.

(6) (3) Synthesis of the Comb Copolymer

(7) 40.5 g of the solution obtained in stage 2 are diluted in 487.5 g of tert-butanol in the reactor thermostatically controlled at 25 C.; 67.7 g of 2-acrylamido-2-methylpropanesulfonic acid powder and 5.7 g of N-[3-(dimethylamino)propyl]acrylamide (DMAPAM) are added thereto; 4.95 g of ammonia are injected into the reaction mixture, so as to obtain a pH approximately equal to 6. 0.5 g of water and 0.48 g of trimethylolpropane triacrylate (TMPTA) are then added. After sparging with nitrogen for 1 h and heating to 60 C., the polymerization is initiated with 1 g of dilauroyl peroxide. After reacting for 3 h, the product is emptied, filtered and dried. The desired comb copolymer is obtained in the form of a white powder [referred to in the following examples as copolymer (1)].

(8) Viscosity of a 1% solution of the comb copolymer in water at 25 C.:

(9) =10 000 mPa.Math.s (Brookfield RVT Spindle 4; Rate: 5 revolutions/minute)

(10) Viscosity of a 1% solution of the comb copolymer in water at 50 C.:

(11) =50 000 mPa.Math.s (Brookfield RVT Spindle 5; Rate: 5 revolutions/minute)

(12) This difference in viscosity observed between 25 C. and 50 C. is characteristic of a heat-sensitive polymer.

Example 2: Antistress Hair Care Product

(13) TABLE-US-00001 Formula Phase A Water: q.s. for 100% Xanthan gum 0.50% Phase B Sepicap MP: 3.00% Phase C Copolymer 1: 4.00% Phase D Butylene glycol: 5.00% Lanol 99: 5.00% Sepicide HB: 0.30% Sepicide CI: 0.20% Fragrance 0.20% Procedure The xanthan gum is dispersed in the water with a deflocculator. Sepicap MP is subsequently added, followed by the compound 1; it is dispersed and then the ingredients of phase D are added.

Example 3: Restructuring Cream Mask for Stressed and Embrittled Hair

(14) TABLE-US-00002 Formula Phase A Montanov 82: 3.00% Lanol P: 6.00% Amonyl DM: 1.00% Isostearyl isononanoate: 5.00% Copolymer 1: 2.50% Phase B Water: q.s. for 100% Phase C Sepicap MP: 3.00% Sepicide HB: 0.30% Sepicide CI: 0.20% Procedure Phase A is melted at 75 C. Phase B is heated to 75 C. A is emulsified in B. The constituents of phase C are introduced at approximately 40 C.

Example 4: Purifying Facial Gel

(15) TABLE-US-00003 Formula Phase A Montaline C 40: 7.00% Pearlescent base 2078: 5.00% Copolymer 1: 2.00% Phase B Water: q.s. for 100%

Example 5: Dye Shampoo

(16) TABLE-US-00004 Formula Phase A Montaline C 40: 15.00% Disodium cocoamphoacetate: 5.00% Cetrimonium chloride: 1.00% Sepiperl N: 3.00% Copolymer 1: 3.00% Phase B Color q.s. Water q.s. for 100%

Example 6: Fluid Emulsion at Alkaline pH

(17) TABLE-US-00005 Marcol 82: 5.0% Sodium hydroxide: 10.0% Water: q.s. for 100% Copolymer 1: 1.5%

Example 7: Rinse-Off Restructuring Cream Mask for Stressed and Embrittled Hair

(18) TABLE-US-00006 Ketrol T: 0.5% Pecosil SPP50: 0.75% N-Cocoyl amino acids: 0.70% Butylene glycol: 3.0% Copolymer 1: 3.0% Montanov 82: 3.0% Jojoba oil: 1.0% Lanol P: 6.0% Amonyl DM: 1.0% Lanol 99: 5.0% Sepicide HB: 0.3% Sepicide CI: 0.2% Fragrance: 0.2% Water: q.s. for 100%

Example 8: Hair Lotion

(19) TABLE-US-00007 Butylene glycol: 3.0% Copolymer 1: 3.0% Simulsol 1293: 3.0% Lactic acid: q.s. pH = 6 Sepicide HB: 0.2% Sepicide CI: 0.3% Fragrance: 0.3% Water: q.s. for 100%

Example 9: Protective and Relaxing Shampoo

(20) TABLE-US-00008 Amonyl 675 SB: 5.0% 28% Sodium lauryl ether sulfate: 35.0% Copolymer 1: 3.0% Sepicide HB: 0.5% Sepicide CI: 0.3% Sodium hydroxide: q.s. pH = 7.2 Fragrance: 0.3% Dye (FDC Blue 1/Yellow 5): q.s. Water: q.s. for 100%

Example 10: Leave-on Protector; Antistress Hair Care Product

(21) TABLE-US-00009 Ketrol T: 0.5% Mixture of cocoyl amino acids: 3.0% Butylene glycol: 5.0% DC 1501: 5.0% Copolymer 1: 4.0% Sepicide HB: 0.5% Sepicide CI: 0.3% Fragrance: 0.3% Water: q.s. for 100%
The definitions of the commercial products used in the examples are as follows:
Montaline C40: (cocammoniumcarbamoyl chloride), sold by Seppic.
Sepiperl N: (cocoyl glucoside 1 cocoyl alcohol), sold by Seppic.
Amonylt DM: (Quaternium 82), sold by Seppic.
Sepicap MP: (Sodium cocoyl amino acids 1 potassium dimethicone copolyol panthenyl phosphate), sold by Seppic.
Simulsol 1293 is hydrogenated and ethoxylated castor oil, with an ethoxylation number equal to 40, sold by Seppic.
Ketrol T is xanthan gum, sold by Kelco.
Lanol 99 is isononyl isononanoate, sold by Seppic.
DC1501 is a mixture of cyclopentasiloxane and dimethiconol, sold by Dow Chemical.
Montanov 82 is an emulsifying agent based on cetearyl alcohol and on cocoyl glucoside.
Sepicide Cl, imidazolidinyl urea, is a preservative, sold by Seppic.
Sepicide HB, which is a mixture of phenoxyethanol, methylparaben, ethylparaben, propylparaben and butylparaben, is a preservative, sold by Seppic.
Lanol P is an additive having a stabilizing effect, sold by Seppic.