Personal cleansing composition

1. A personal cleansing composition comprising:

a) an amidoamine surfactant of the formula:

R 5 R 6 N—(CH 2 ) x —NHC(O)R 7   (I)

wherein R 5 and R 6 are independently methyl or ethyl, x is 2 or 3, and R 7 is C6 to C30 alkyl, wherein R 7 is saturated or unsaturated,

b) 5 to 15 wt. % cleansing surfactant,

c) water, and

d) protonating agent

wherein:

the cleansing surfactant comprises from 85 to 100% by weight of a combination of betaine surfactant and taurate surfactant, and wherein:

when the composition comprises 5 to 6 weight percent of cleansing surfactant, the weight ratio of betaine surfactant to taurate surfactant is from 55:45 to 45:55;

when composition comprises from greater than 6 weight percent to up to 10 weight percent of cleansing surfactant, the weight ratio of betaine surfactant to taurate surfactant is from 80:20: to 40:60; and

when the composition comprises greater than 10 weight percent of cleansing surfactant, the weight ratio of betaine surfactant to taurate surfactant is from 80:20: to 20:80;

wherein the composition is essentially free of sulfate surfactant.

2. The personal cleansing composition according to claim 1 , wherein the amidoamine surfactant is present in an amount of up to 2 wt. %, based on the total weight of the composition.

3. The personal cleansing composition according to claim 1 , wherein the composition comprises from 0.05 to 1 wt. % of the amidoamine surfactant, based on the total weight of the composition.

4. The personal cleansing composition according to claim 1 , wherein the betaine surfactant is an amidobetaine and the taurate surfactant is an acyl taurate.

5. The personal cleansing composition according to claim 1 , wherein the taurate surfactant comprises sodium methyl cocoyl taurate and the betaine surfactant comprises cocamidopropyl betaine.

6. The personal cleansing composition according to claim 1 , wherein the composition comprises from 6 to 12 wt. % of cleansing surfactant, based on the total weight of the composition.

7. The personal cleansing composition according to claim 1 , wherein the composition has an isotropic surfactant phase.

8. The composition according to claim 1 , wherein the amidoamine surfactant comprises stearamidopropyl dimethyl amine.

9. The personal cleansing composition according to claim 1 , that is transparent.

10. The personal cleansing composition according to claim 1 that is essentially free of (meth)acrylate polymers and copolymers.

11. The personal cleansing composition according to claim 1 that further comprises electrolyte.

12. A method of adjusting the viscosity of a composition, the method comprising the steps of:

I) providing a composition according to claim 1 : and

II) adding electrolyte to the composition,

wherein the addition of electrolyte increases the viscosity of the resulting composition.

13. The method according to claim 12 wherein the electrolyte is sodium chloride, ammonium chloride, magnesium chloride, sodium sulfate or sodium citrate.

14. The personal cleansing composition according to claim 1 , wherein the amidoamine is selected from the group consisting of stearamidopropyldimethylamine, stearamidoethyldiethylamine, stearamidopropyldiethylamine, palmitoamidopropyldimethylamine, palmitamidopropyldiethylamine, palmitoamidoethyldimethylamine, behenamidopropyldimethylamine, behenamidoethyldimethylamine, and arachiamidopropyldimethylamine.

15. The personal cleansing composition according to claim 4 , wherein the acyl taurate is of the formula:

R8C(O)N(R9)(CH2) y SO3M  (IIa),

wherein R8 is C6 to C30 alkyl,

y is 2 or 3,

R9 is hydrogen or methyl, and

M is a solubilizing cation.

16. The personal cleansing composition according to claim 15 , wherein y is 2.

17. The personal cleansing composition according to claim 15 , wherein M is hydrogen, ammonium, alkali metal cation, a C1 to C4 alkanolammonium cation, or a basic amino acid cation.

18. The personal cleansing composition according to claim 1 , wherein the betaine is represented by the general formula:

R10[C(O)NH—(CH2) y]z -N+(R11)(R12)CH2CO2  (III)

where R10 is C6 to C30,

z is 0 or 1,

R11 and R12 are independently alkyl, hydroxyalkyl or carboxyalkyl of 1 to 3 carbon atoms, and

y is 2 or 3; and salts thereof.

19. The personal cleansing composition according to claim 18 , wherein R11 and R12 are methyl.