Microbiologically Stable Surfactant-Containing Formulation

1 . An aqueous formulation comprising

a) an anionic surfactant selected from the group of alkyl sulphates, alkyl ether sulphates and/or acyl glutamates,

b) an amphoteric surfactant selected from the group consisting of alkyl betaines and/or amidoalkyl betaines,

c) 2-methyl-1,3-propanediol,

wherein

d) said formulation has a pH of 6 to 10,

e) comprises no further preservatives for microbiological stabilization selected from the group consisting of:

e1) authorized preservatives cited in Annex V of Regulation (EC) No. 1223/2009, and

e2) multifunctional additives selected from the group of linear or branched, saturated or unsaturated aliphatic or aromatic hydroxamic acids having a number of 6-16 carbon atoms and aromatic alcohols of the general structure

Ar—(CH2) n -OH

where n=2-4.

2 . The aqueous formulation according to claim 1 , wherein the anionic surfactant according to a) is present at a concentration of 0.1 to 30% by weight.

3 . The aqueous formulation according to claim 2 , wherein the anionic surfactant according to a) is selected from the group consisting of sodium lauryl sulphate, ammonium lauryl sulphate, sodium laureth sulphate, sodium cocoyl glutamate and disodium cocoyl glutamate.

4 . The aqueous formulation according to claim 1 , wherein the amphoteric surfactant according to b) is present at a concentration of 0.1 to 20% by weight.

5 . The aqueous formulation according to claim 4 , wherein the amphoteric surfactant according to b) is a quaternary surfactant selected from the group consisting of cocoamidopropyl betaine and coco betaine.

6 . The aqueous formulation according to claim 1 , wherein 2-methyl-1,3-propanediol is present at a concentration of 0.1 to 10% by weight.

7 . The aqueous formulation according to claim 1 , wherein 2-methyl-1,3-propanediol is used for microbiological stabilization of the formulation against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans and/or Aspergillus brasiliensis.

8 . The aqueous formulation according to claim 1 , wherein the pH is from 6 to 9.5.

9 . A cosmetic product for cleansing and/or care of skin and/or hair, wherein said product comprises a formulation according claim 1 .

10 . A formulation according to claim 1 in a cosmetic product for cleansing and/or care of skin and/or hair.

11 . An aqueous formulation comprising 2-methyl-1,3-propanediol as sole biocide for microbiological stabilization:

a) at least one anionic surfactant selected from the group of alkyl sulphates, alkyl ether sulphates and/or acyl glutamates,

b) at least one amphoteric surfactant selected from the group of alkyl betaines and/or amidoalkyl betaines.

12 - 13 . (canceled)

14 . The aqueous formulation according to claim 1 , wherein the anionic surfactant according to a) is present at a concentration of 2 to 25% by weight.

15 . The aqueous formulation according to claim 1 , wherein the anionic surfactant according to a) is present at a concentration of 5 to 20% by weight.

16 . The aqueous formulation according to claim 1 , wherein the amphoteric surfactant according to b) is present at a concentration of 1 to 15% by weight.

17 . The aqueous formulation according to claim 2 , wherein the amphoteric surfactant according to b) is present at a concentration of 1 to 15% by weight.

18 . The aqueous formulation according to claim 3 , wherein the amphoteric surfactant according to b) is present at a concentration of 1 to 15% by weight.

19 . The aqueous formulation according to claim 1 , wherein the 2-methyl-1,3-propanediol is present at a concentration of 1 to 8% by weight.

20 . The aqueous formulation according to claim 1 , wherein the pH is from 6 to 9.