Cleansing composition
There is provided a cleansing composition which has creamy foaming and excellent cleansing power, provides no stretched feeling of skin after rinsing and a refreshed feeling of skin, is excellent in storage stability and exhibits no reduction in physical properties, formation of precipitates and yellowing during a long-term storage period by combining N-acyl-aspartic acid or a salt thereof and N-acyl-diaspartic acid or a salt thereof, which have the same molecular structure of the N-acyl group, with a higher fatty acid or a salt thereof which has the same alkyl group as that of the above described N-acyl residue.
1. A cleansing composition, comprising:
(A) N-acyl-aspartic acid or a salt thereof represented by formula (1):
wherein R is an alkyl group having from 7 to 23 carbon atoms, and M 1 and M 2 are each, independently, a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium, alkylammonium, alkanolammonium or a protonated basic amino acid;
(B) a first N-acyl-diaspartic acid or a salt thereof, represented by formula (2):
wherein R is the same alkyl group specified in formula (1), and M 3 , M 4 and M 5 are each, independently, a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium, alkylammonium, alkanolammonium or a protonated basic amino acid;
a second N-acyl diaspartic acid or salt thereof, represented by formula (3):
wherein R is the same as in formula (2), and M 6 , M 7 and M 8 are each, independently, a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium, alkylammonium, alkanolammonium or a protonated basic amino acid,
and the weight ratio of the first N-acyl-diaspartic acid or a salt thereof represented by formula (2) to the second N-acyl-diaspartic acid or a salt thereof represented by formula (3) is 1:3 to 3:1; and
(C) a higher fatty acid or a salt thereof represented by formula (4):
[Formula 4]
R—COOM 9 (4)
wherein R is the same as in formula (2), and M 9 is a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium, alkylammonium, alkanolammonium or a protonated basic amino acid,
wherein in a simile composition, R is defined the same in formulae (1) through (4) such that R has the same number of carbon atoms in components (A), (B) and (C).
2. The cleansing composition according to claim 1 , wherein the amount of components (B) is 0.1 to 15% by mass based on the total amount of components (A) and (B), and the amount of component (C) is 0.1 to 15% by mass based on the total amount of components (A) and (C).
3. The cleansing composition according to claim 2 , wherein the amount of components (B) is 0.1 to 8% by mass based on the total amount of components (A) and (B), and the amount of component (C) is 0.1 to 10% by mass based on the total amount of components (A) and (C).
4. The cleansing composition according to claim 1 , wherein the composition has a pH of from 5.0 to 7.0.
5. The cleansing composition according to claim 1 , wherein R in component (A) has from 9 to 17 carbon atoms.
6. The cleansing composition according to claim 1 , wherein M 1 to M 9 in formulas (1) to (4) are one or more selected from a hydrogen atom, sodium, lithium, potassium, ammonium and triethanolammonium.
7. The cleansing composition according to claim 6 , wherein M 1 to M 9 in formulas (1) to (4) are only one selected from sodium, lithium, potassium, ammonium and triethanolammonium, other than a hydrogen atom.
8. The cleansing composition according to claim 7 , wherein M 1 to M 9 in formulas (1) to (4) are selected only from a hydrogen atom and sodium.
9. A method for producing a cleansing composition of claim 1 in which N-acyl-aspartic acid or a salt thereof is used as component (A), wherein the N-acyl-aspartic acid or a salt thereof is prepared by the steps comprising:
adjusting the N-acyl-aspartic acid or a salt thereof to a pH of 6.0 or higher; and then
adjusting the resulting mixture to a final pH of from 4.5 to 6.0,
wherein the difference between the highest pH and the final pH is 0.5 or more.
10. The cleansing composition according to claim 1 , comprising from 0.005 to 0.3 part by mass of phosphorus.
11. The cleansing composition according to claim 1 , comprising from 0.005 to 0.08 part by mass of organic phosphorus.