Emulsifier-free finely disperse systems of the oil-in-water and water-in-oil type

Abstract

Pickering emulsions, which are finely disperse systems of the water-in-oil or oil-in-water type, comprising (1) an oil phase which comprises at least 0.5% by weight, based on the weight of the oil phase, of at least one oil component chosen from the group of oils having a viscosity which is less than 30 mPa.s (measured at a shear gradient of 500/s and a temperature of 25° C.), (2) a water phase, (3) at least one type of microfine particles which a) have an average particle size of less than 200 nm, which b) display both hydrophilic and lipophilic properties, i.e. which have amphiphilic character, and are dispersible both in water and in oil and which c) have optionally been coated on the surface, and (4) at most 0.5% by weight of one or more emulsifiers.

1 . Pickering emulsions, which are finely disperse systems of the water-in-oil or oil-in-water type, comprising 
 (1) an oil phase which comprises at least 0.5% by weight, based on the weight of the oil phase, of at least one oil component chosen from the group of oils having a viscosity which is less than 30 mPa.s (measured at a shear gradient of 500/s and a temperature of 25° C.),    (2) a water phase,    (3) at least one type of microfine particles which 
 a) have an average particle size of less than 200 nm, which  
 b) display both hydrophilic and lipophilic properties, i.e. which have amphiphilic character, and are dispersible both in water and in oil and which  
 c) have optionally been coated on the surface, and  
   (4) at most 0.5% by weight of one or more emulsifiers.    
     
     
         2 . Pickering emulsions according to  claim 1 , characterized in that they are emulsifier-free.  
     
     
         3 . Pickering emulsions according to one of the preceding claims, characterized in that the content of the particles used is between 0.1% by weight and 30% by weight, based on the total weight of the preparations.  
     
     
         4 . Pickering emulsions according to one of the preceding claims, characterized in that the particle diameter of the particles used is between 5 nm and 100 nm.  
     
     
         5 . Pickering emulsions according to one of the preceding claims, characterized in that the particles used are chosen from the group consisting of amphiphilic metal oxides, boron nitride, microfine polymer particles and modified polysaccharides, it being possible for the particles to be present individually or as a mixture.  
     
     
         6 . Pickering emulsions according to one of the preceding claims, characterized in that the particles used have been surface-treated to repel water, where the amphiphilic character of the particles is formed or retained.  
     
     
         7 . Pickering emulsions according to one of the preceding claims, characterized in that the viscosity of the oils is less than 20 mPa.s (measured at a shear gradient of 500/s and a temperature of 25° C.).  
     
     
         8 . Pickering emulsions according to one of the preceding claims, characterized in that they comprise other auxiliaries which can contribute to reducing or preventing a dull or dry feel on the skin following their application.  
     
     
         9 . Use of at least one oil component chosen from the group of oils having a viscosity which is less than 30 mPa.s (measured at a shear gradient of 500/s and a temperature of 25° C.) in a cosmetic or dermatological preparation for reducing or preventing a dull or dry feel on the skin following its application.