Polyurethane dispersions for use in personal care products

1. An aqueous polyurethane dispersion suitable for use in personal care products, the dispersed polyurethane comprising the reaction product of:

A) a prepolymer according to the formula:

wherein

R 1 represents a bivalent radical of a polyol,

R 2 represents a radical of an aliphatic or cycloaliphatic polyisocyanate,

R 3 represents a radical of a low molecular weight diol, optionally substituted with ionic groups,

n is from 0 to 5, and

m is >1;

B) at least one chain extender according to the formula:

H 2 N—R 4 —NH 2

wherein R 4 represents an alkylene or alkylene oxide radical not substituted with ionic or potentially ionic groups; and

C) at least one chain extender selected from the group consisting of the sodium salt of N-(2-aminoethyl)-2-aminoethane sulfonic acid and compounds according to the formula:

H 2 N—R 5 —NH 2

wherein R 5 represents an alkylene radical substituted with ionic or potentially ionic groups.

2. The aqueous polyurethane dispersion of claim 1 , wherein the reactants further include a chain terminator according to the formula:

wherein R 6 is an H atom or alkylene radical optionally having a hydroxyl end and R 7 is alkylene radical optionally having a hydroxyl end.

3. The aqueous polyurethane of claim 2 , wherein the chain terminator is selected from the group consisting of methylamine, ethylamine, propylamine, butylamine, octylamine, laurylamine, stearylamine, isononyloxy-propylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, N-methylaminopropylamine, diethyl(methyl)aminopropylamine, morpholine, piperidine and diethanolamine, amide amines of diprimary amines and monocarboxylic acids, monoketimes of diprimary amines, primary/tertiary amines, methanol, butanol, hexanol, 2-ethylhexyl alcohol, isodecyl alcohol, aminomethylpropanol and mixtures thereof.

4. The aqueous polyurethane of claim 1 , wherein the polyisocyanate is selected from the group consisting of tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate (isophorone diisocyanate), 4,4′-diisocyanatodicyclohexylmethane, 4,4′-diisocyanatodicyclohexylpropane-(2,2) and mixtures thereof.

5. The aqueous polyurethane of claim 1 , wherein the low molecular weight diol is selected from the group consisting of ethylene glycol, diethylene glycol, propane 1,2-diol, propane 1,3-diol, butane 1,4-diol, butylene 1,3-glycol, cyclohexane diol, 1,4-cyclohexane dimethanol, hexane 1,6-diol, bisphenol A (2,2-bis(4-hydroxyphenyl)propane), hydrogenated bisphenol A (2,2-bis(4-hydroxycyclohexyl)propane) and mixtures thereof.

6. The aqueous polyurethane of claim 1 , wherein the first chain extender B) is a mixture of 3-{2-[2-(3-aminopropoxy)ethoxy]ethoxy}propylamine and ethylenediamine.

7. The aqueous polyurethane of claim 3 , wherein the first chain extender B) is a mixture of 3-{2-[2-(3-aminopropoxy)ethoxy]ethoxy}propylamine and ethylenediamine.

8. The aqueous polyurethane of claim 1 , wherein the second chain extender C) is the sodium salt of N-(2-aminoethyl)-2-aminoethane sulfonic acid.

9. The aqueous polyurethane of claim 1 , wherein n is from 1 to 3, and m is from 1 to 5.

10. The aqueous polyurethane of claim 1 , wherein either R 3 is a radical of diethylene glycol or R 4 is a radical of 3-{2-[2-(3-aminopropoxy)ethoxy]ethoxy}propylamine.

11. A hair fixative comprising the aqueous polyurethane dispersion of claim 1 and water.

12. A hair fixative comprising the aqueous polyurethane dispersion of claim 1 and ethanol.

13. A suntan lotion comprising the polyurethane dispersion of claim 1 .