Melt-sprayed curing agent powder and powder coating compositions made therefrom

Abstract

Powder comprising particles of a curing agent selected from the group consisting of azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid and the anhydrides of said acids.

What is claimed:  
     
         1 . Powder comprising substantially spherical particles of at least one compound selected from the group consisting of azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, and the anhydrides of said acids, said particles having a particle size distribution as follows:  
       
         
           
             
               
                 
                   d90 
                   - 
                   d10 
                 
                 d50 
               
               < 
               1.90 
             
           
           
           
               
           
         
       
       wherein: 
 d50 is a particle diameter at which 50% of the particles have diameters which are greater or smaller than the d50 value;  
 d90 is a particle diameter at which 90% of the particles have diameters which are smaller than the d90 value;  
 d10 is the particle diameter at which 10% of the particles have diameters which are smaller than the d10 value; and  
 d50 is 8 to 30 micrometers.  
 
     
     
         2 . Powder as in  claim 1 , wherein said particles further comprise an additive selected form the group consisting of flow modifiers, pigments, degassing agents, adhesion modifiers, slip agents, and ultraviolet absorbers.  
     
     
         3 . Process for making a powder of substantially spherical particles comprising a compound selected from the group consisting of azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, and the anhydrides of said acids, said process comprising spraying molten compound from a nozzle into a walled chamber to form a spray comprising droplets of said compound, said chamber being sized to allow said droplets to solidify before they contact the wall of said chamber.  
     
     
         4 . Powder coating composition comprising a cross-linkable base resin and the powder of  claim 1.