Perfumes in the form of aqueous microemulsions
Disclosed is a microemulsion of oil-in-water type including, preferably consisting of, by weight relative to the total weight of microemulsion: •70% to 94% of water, •1% to 15% of at least one hydrophobic fragrancing substance, •4% to 20% of at least one preferably volatile solvo-surfactant, and •0.1% to 15%, preferably 1% to 13%, of at least one hydrotropic agent or at least one surfactant selected from anionic surfactants, cationic surfactants, amphoteric surfactants and non-ionic surfactants. The solvo-surfactant is selected from monoalkylated glycerol derivatives of following formula (I): wherein the “alkyl” group is a linear or branched alkyl group including from 1 to 8 carbon atoms, and R and R′ are each independently H or a linear or branched alkyl group including from 1 to 5 carbon atoms, with the proviso that R is different from R′, and mixtures thereof.
1. A microemulsion of oil-in-water type comprising by weight relative to the total weight of microemulsion:
70% to 94% of water,
1% to 15% of at least one hydrophobic fragrancing substance,
4% to 20% of at least one volatile solvo-surfactant, and
0.1% to 15% of at least one hydrotropic agent or at least one surfactant selected from anionic surfactants, cationic surfactants, amphoteric surfactants and non-ionic surfactants, said solvo-surfactant being selected from monoalkylated glycerol derivatives of following formula (I):
wherein the “alkyl” group is a linear or branched alkyl group comprising from 1 to 8 carbon atoms, and R and R′ are each independently H or a linear or branched alkyl group comprising from 1 to 5 carbon atoms, with the proviso that R is different from R′, and mixtures thereof.
2. The microemulsion as claimed in claim 1 , wherein the hydrophobic fragrancing substance is a natural hydrophobic fragrancing substance selected from terpenes, essential oils and natural compounds having odoriferous properties.
3. The microemulsion as claimed in claim 1 , wherein, in the monoalkylated glycerol derivative of formula (I), the “alkyl” group is a linear alkyl group comprising 3, 4 or 5 carbon atoms, and R and R′ are each independently H or a methyl or ethyl group, with the proviso that R is different from R′.
4. The microemulsion as claimed in claim 1 , wherein, in the monoalkylated glycerol derivative of formula (I), the “alkyl” group is a linear alkyl group comprising 3, 4 or 5 carbon atoms, and R is a methyl group, and R′ is H.
5. The microemulsion as claimed in claim 1 , which is free of ethanol.
6. The microemulsion as claimed in claim 1 , consisting of:
70% to 90% of water,
5% to 12% of at least one hydrophobic fragrancing substance,
4% to 18% of at least one volatile solvo-surfactant, and
0.1% to 10% of at least one hydrotropic agent or at least one surfactant selected from anionic surfactants, cationic surfactants, amphoteric surfactants and non-ionic surfactants.
7. The microemulsion as claimed in claim 1 , wherein the surfactant is an anionic surfactant selected from:
alkyl sulfonates,
alkylaryl sulfonates of formula
wherein w is an integer from 8 to 12,
propoxy sulfates of formula
wherein the number of propoxylate units n is from 4 to 8,
alkyl sulfates,
and salts of fatty acids of formula R—CO 2 − M + , wherein R represents a linear or branched, saturated or unsaturated carbon-based chain containing 8 to 18 carbon atoms, and M + represents a cation selected from the ions Na + , K + , NH 4 + , (HOCH 2 CH 2 ) 3 NH + .
8. The microemulsion as claimed in claim 1 , wherein the surfactant is a non-ionic surfactant selected from:
alkanolamides, with the proviso that said alkanolamide is not a polyol,
alkylpolyglycosides,
polyglycerol ethers,
and polyglycerol esters,
the surfactant is an amphoteric surfactant selected from:
betaines,
and amine oxides, or
the surfactant is a cationic surfactant selected from:
tetraalkylammonium salts,
trialkylammonium salts,
pyridinium salts,
benzalkonium salts,
ammonium salts of triethanolamine of formula
(HO—CH 2 —CH 2 ) 3 NH + X—
wherein
X − represents an anion selected from Cl—, Br—, I—, CH3COO— or lactate.
9. The microemulsion as claimed in claim 1 , wherein the hydrotropic agent is selected from arylsulfonic acids and alkyl glucosides.
10. A fine fragrance composition or a cosmetic or body hygiene composition, comprising the microemulsion of claim 1 .
11. The microemulsion as claimed in claim 7 , wherein the anionic surfactant is selected from:
dihexyl sulfosuccinate of formula:
wherein M + represents Na + , K + , NH 4 + , (HOCH 2 CH 2 ) 3 NH + or 2-ethylhexyl sulfosuccinate of formula:
wherein M + represents Na + , K + , NH 4 + , (HOCH 2 CH 2 ) 3 NH + ,
isododecylbenzenesulfonate of formula:
salts of lauryl sulfate chosen from sodium dodecyl sulfate and sodium alkylether sulfates,
the oleic acid salt of formula CH 3 (CH 2 ) 7 CH═CH(CH 2 ) 7 CO 2 − M + ,
wherein M + has the meaning as defined above.
12. The microemulsion as claimed in claim 8 , wherein:
the surfactant is an non-ionic surfactant selected from
monoethanolamide of formula
the surfactant is an amphoteric surfactant selected from:
cocamidopropyl betaine of formula
lauryldimethylamine oxide of formula
the surfactant is a cationic surfactant selected from:
dialkyldimethylammonium salts of formula
wherein
X − represents an anion selected from Cl − , Br − , I − , CH 3 COO − or lactate,
n is the number of methylenes, from 6 to 12,
trialkylammonium halides,
cetylpyridinium salt of formula
wherein X − has the meanings given above,
benzalkonium salts of formula
wherein
X − has the meanings given above,
p is from 8 to 18.
13. The microemulsion as claimed in claim 12 , wherein:
dialkyldimethylammonim salts are a didecyldimethylammonium salt of formula:
wherein X − represents an anion selected from Cl − , Br − , I − , CH 3 COO − or lactate,
trialkylammonium halides are dodecyltrimethylammonium bromide of formula H 3 C(CH 2 ) 11 N + (CH 3 ) 3 .