Method for producing nanoparticles suspensions

Abstract

The invention relates to a method for producing a suspension of an undecomposed meltable material having an average particle diameter of between 5 to 500 nm. The inventive method enables stable suspensions to be produced and is characterised in that it only requires a simple technical infrastructure in many production plants, it delivers high space-time yields, and can easily be scaled up.

1 . A process for the production of a suspension of a substance which can be melted without decomposing with a mean particle diameter in the range from 5 to 500 nm, characterized in that 
 (a) an emulsion is prepared from the substance which can be melted without decomposing, a liquid phase in which the substance is poorly soluble and an effective quantity of at least one surface modifier and    (b) the resulting emulsion is expanded into a zone of reduced pressure so that the emulsion is cooled to below the melting point of the substance.    
     
     
         2 . A process as claimed in  claim 1 , characterized in that the mean particle diameter is in the range from 10 to 300 nm.  
     
     
         3 . A process as claimed in  claim 1  or  2 , characterized in that the emulsion from step (a) is prepared by melting the substance together with the liquid phase and the at least one surface modifier.  
     
     
         4 . A process as claimed in  claim 1  or  2 , characterized in that the emulsion from step (a) is prepared by initially introducing the molten substance and then adding the liquid phase and at least one surface modifier either together or successively.  
     
     
         5 . A process as claimed in any of  claims 1  to  4 , characterized in that the cooling of the emulsion to below the melting point of the substance in step (c) is effected by partial evaporation of the liquid phase.  
     
     
         6 . A process as claimed in any of  claims 1  to  5 , characterized in that the pressure in step (b) is in the range from 10 to 800 mbar and preferably in the range from 20 to 300 mbar.  
     
     
         7 . A process as claimed in any of  claims 1  to  6 , characterized in that 5 to 50% by weight and preferably 10 to 20% by weight of the liquid phase is removed from the emulsion in step (b), based on the total weight of the emulsion before expansion.