W/o nanoemulsion and method for producing same

Abstract

The present invention provides a W/O nanoemulsion which remains stable even if stored for long periods of six months, for example. The W/O nanoemulsion of the present invention comprises: a) a water content of greater than 0 wt % but no greater than 30 wt %; b) an oil content of less than 100 wt % but no less than 70 wt %; c) 1 to 30 parts by weight of at least one nonionic surfactant for every 100 parts by weight of oil, the nonionic surfactant having an HLB value of 1 to 10; and d) 0.1 to 30 parts by weight of at least one selected from the group consisting of an anionic surfactant, a cationic surfactant, and an amphoteric surfactant, for every 100 parts by weight of water, wherein the average particle size of 50% of the water particles in the W/O nanoemulsion is 100 nm or less.

1 . A W/O type emulsion comprising:
 a) water: more than 0 wt % but no more than 30 wt %;   b) oil: less than 100 wt % but no less than 70 wt %;   c) at least one nonionic surfactant having an HLB value of 1 to 10:1 to 30 parts by weight, which are normalized in a case where an amount of the oil is considered as 100 parts by weight; and   d) at least one selected from the group consisting of anionic surfactants, cationic surfactants and amphoteric surfactants: 0.1 to 30 parts by weight, which are normalized in a case where an amount of the water is considered as 100 parts by weight,   wherein 50% average particle size of the water particle in the W/O type emulsion is 100 nm or less.   
     
     
         2 . The W/O type emulsion according to  claim 1 , wherein the 50% average particle size of the water particle in the W/O type emulsion is 5 to 100 nm. 
     
     
         3 . The W/O type emulsion according to  claim 1 , wherein the b) oil is at least one selected from the group consisting of kerosene, gasoline, light oil, heavy oil, alcohol, biofuel and ethyl tert-butyl ether. 
     
     
         4 . The W/O type emulsion according to  claim 1 , wherein the c) nonionic surfactant is at least one selected from the group consisting of polyoxyethylene glycol, fatty acid sorbitan esters, alkyl polyglucosides, fatty acid diethanolamides, alkyl monoglyceryl ethers, alkyl glycosides, polyethylene glycol, and polyvinyl alcohol. 
     
     
         5 . The W/O type emulsion according to  claim 1 , wherein the d) surfactant comprises an anionic surfactant. 
     
     
         6 . The W/O type emulsion according to  claim 1 , wherein the d) surfactant consists of an anionic surfactant(s). 
     
     
         7 . The W/O type emulsion according to  claim 1 , wherein the anionic surfactant is at least one selected from the group consisting of fatty acid salts, monoalkyl sulfates, alkyl polyoxyethylene sulfates, alkylbenezene sulfonates, monoalkyl phosphates, and sulfosuccinate-type surfactants. 
     
     
         8 . The W/O type emulsion according to  claim 1 , wherein the surfactant d) comprises a cationic surfactant. 
     
     
         9 . The W/O type emulsion according to  claim 1 , wherein the surfactant d) consists of a cationic surfactant(s). 
     
     
         10 . The W/O type emulsion according to  claim 1 , wherein the cationic surfactant is at least one selected from the group consisting of alkyltrimethyl ammonium salts, dialkyldimethyl ammonium salts, and alkylbenzyldimethyl ammonium salts. 
     
     
         11 . The W/O type emulsion according to  claim 1 , wherein the surfactant d) comprises an amphoteric surfactant. 
     
     
         12 . The W/O type emulsion according to  claim 1 , wherein the surfactant d) consists of an amphoteric surfactant(s). 
     
     
         13 . The W/O type emulsion according to  claim 1 , wherein the amphoteric surfactant is at least one selected from the group consisting of alkyldimethylamine oxides and alkylcarboxy betaines. 
     
     
         14 . A fuel comprising the W/O type emulsion according to  claim 1 . 
     
     
         15 . A fuel consisting of the W/O type emulsion according to  claim 1 . 
     
     
         16 . A method for producing a W/O type emulsion comprising:
 a) water: more than 0 wt % but no more than 30 wt %;   b) oil: less than 100 wt % but no less than 70 wt %;   c) at least one nonionic surfactant having an HLB value of 1 to 10:1 to 30 parts by weight, which are normalized in a case where an amount of the oil is considered as 100 parts by weight; and   d) at least one selected from the group consisting of anionic surfactants, cationic surfactants and amphoteric surfactants: 0.1 to 30 parts by weight, which are normalized in a case where an amount of the water is considered as 100 parts by weight,   wherein 50% average particle size of the water particle in the W/O type emulsion is 100 nm or less,   the method comprising the steps of:   i) preparing the a) water;   ii) preparing the b) oil;   iii) preparing the c) nonionic surfactant;   iv) preparing the d) surfactant; and   v) mixing the a) to d);   to obtain the W/O type emulsion.   
     
     
         17 . The method according to  claim 16 , wherein the mixing step v) comprises the steps of
 v-1) mixing the oil of the step ii); and the nonionic surfactant of the step iii), separately from step v-1), v-2) mixing the water of the step i) and the surfactant of the step iv) and   v-3) mixing the mixture obtained in the step v-1) and the mixture obtained in the step v-2).