Rheology modifier/hair styling resin

1. A rheology modifier/hair styling resin consisting of a crosslinked, linear poly(vinyl amide/polymerizable carboxylic acid) copolymer having a composition, by weight, of 25–75% of a vinyl amide monomer selected from vinyl pyrrolidone. vinyl caprolactam, N-vinyl formamide, N-vinyl-acetamide, N-vinyl-N-methylacetamide and mixtures thereof, and 25–75% of a polymerizable carboxylic acid monomer selected from (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid and mixtures thereof, and a crosslinker in an amount of 0.5–2%. based on weight of total monomers, which is characterized by an aqueous solution having a viscosity of 55,000 cps at a pH of 9 (Brookfield RVT, T-bar C@ 10 RPM, 60 sec., 1% resin solids in water).

2. A rheology modifier/hair styling resin according to claim 1 wherein said vinyl amide is vinyl pyrrolidone.

3. A rheology modifier/hair styling resin according to claim 1 wherein said polymerizable carboxylic acid is acrylic acid.

4. A rheology modifier/hair styling resin according to claim 1 wherein said crosslinker has at least two free radical polymerizable groups in the molecule.

5. A rheology modifier/hair styling resin according to claim 4 wherein said crosslinker is selected from pentaerythritol triallylether, pentaerythritol triacrylate, pentaerythritol tetraacrylate and methylene bisacrylamide.

6. A process of making the rheology modifier/hair styling resin of claim 1 which consists of precipitation polymerizing, by wt., 5–50% of a reaction mixture of 25–75% of a vinyl amide and 25–75% of a polymerizable carboxylic acid, and 0.5–2% of a crosslinker, based on total monomers, in 50–95% of a non-polar removable organic solvent, in the presence of 0.1–5% of a free radical initiator, based on total weight of monomers, and removing the solvent, to provide the resin in powder form.

7. A process according to claim 6 wherein said reaction mixture consists of 10–25% of said monomers and 75–90% of said solvent.

8. A hair care composition including the rheology modifier/hair styling resin of claim 1 .

9. A hair care composition according to claim 8 including 0.1–20% by wt. of said resin.

10. A hair care composition according to claim 8 which exhibits a curl retention of 80% to 100% over a 4-hour period at 90% RH and 80° F.

11. A hair care composition according to claim 10 wherein said retention is about 90%.

12. A personal care composition including the resin of claim 1 .

13. A personal care composition according to claim 12 which is a skin care formulation.

14. A personal care composition according to claim 13 which is an absorbent composition.

15. A personal care composition according to claim 12 which includes a thickener.

16. A personal care composition according to claim 15 wherein said thickener is a crosslinked polyacrylic acid or its copolymer.

17. A personal care composition according to claim 15 wherein said thickener is crosslinked polymethylvinyl ether/maleic anhydride copolymer.

18. An aqueous hair care composition according to claim 8 having a yield stress value of 10 to 100,000 dynes/cm 2 .

19. A composition according to claim 18 wherein said value is 100 to 10,000 dynes/cm 2 .

20. A hair care composition including the rheology modifier of claim 1 which is a hair fixative, a styling gel, a crème, a mousse, or a spray.

21. A hair care composition according to claim 9 which includes 0.2–10% by wt. of said resin.

22. A hair care composition according to claim 21 which includes 0.5–5% by wt. of said resin.