Method for producing a granular formulation of plastic-soluble colorants

Abstract

The present invention relates to a method of producing a granular formulation of colorants soluble in plastics, which method comprises suspending in water a filter cake obtained from preparation of the colorant, adding thereto from 0.1 to 5.0% by weight, calculated with respect to the weight of colorant, of a polyvinylpyrrolidone or of a sodium lauryl sulfate and, where appropriate, further adjuvants, and then drying the aqueous suspension to form granules, to the granular formulations obtainable according to that method, and to the use thereof in the production of colored plastics or colored polymeric particles.

What is claimed is:  
     
         1 . A method of producing a granular formulation of a colorant that is soluble in plastics, which comprises suspending in water a filter cake obtained from preparation of the colorant, addition thereto from 0.1 to 5.0% by weight, calculated with respect to the weight of colorant, of a polyvinylpyrrolidone or of a sodium lauryl sulfate and, where appropriate, further adjuvants, as then drying the aqueous suspension to form granules.  
     
     
         2 . A method according to  claim 1 , wherein from 0.1 to 5.0% by weight, calculated with respect to the weight of colorant, of a polyvinylpyrrolidone is used.  
     
     
         3 . A method according to  claim 1 , wherein from 0.1 to 5.0% by weight, calculated with respect to the weight of colorant, of a sodium lauryl sulfate is used.  
     
     
         4 . A method according to any one of  claims 1  to  3 , wherein there is used, as a further adjuvant, a viscosity regulator.  
     
     
         5 . A method according to  claim 4 , wherein the viscosity regulator used is hydroxypropyl methylcellulose, hydroxypropylcellulose or methylcellulose.  
     
     
         6 . A method according to any one of  claims 1  to  5 , wherein the granulation is carried out with spray drying.  
     
     
         7 . A granular formulation of a colorant soluble in plastics, which comprises 
 (A) a colorant soluble in plastics,    (B) from 0.1 to 5.0% by weight, calculated with respect to the weight of colorant, of a polyvinylpyrrolidone or of a sodium lauryl sulfate and,    (C) where appropriate, further adjuvants.    
     
     
         8 . A method of producing colored plastics or colored polymeric particles, which comprises using a granular formulation according to  claim 7 .  
     
     
         9 . Use of a granular formulation according to  claim 7  in the production of colored plastics of colored polymeric particles.  
     
     
         10 . Use of a granular formulation according to  claim 7  for coloring food packaging.