Process for producing metal flakes

Abstract

The present invention provides a jetting process for the production of flakes with uniform size distribution to be used in pigments comprising the steps of ejecting molten metal from a jet head and collecting droplets of metal on a solid collecting substrate or collecting droplets of metal in or on a collecting substrate.

1 .- 32 . (canceled) 
     
     
         33 . A metal pigment comprising metal flakes having a median particle diameter of 100 μm or less and a particle size distribution such that at least 90% by volume of the metal flakes have a particle diameter within ±25% of the median particle diameter. 
     
     
         34 . A metal pigment according to  claim 33  comprising metal flakes having a median particle diameter of 50 μm or less. 
     
     
         35 . A metal pigment according to  claim 33  comprising metal flakes having a median particle diameter of 30 μm or less. 
     
     
         36 . A metal pigment according to  claim 33  comprising metal flakes having a median particle diameter of 20 μm or less. 
     
     
         37 . A metal pigment according to  claim 33  comprising metal flakes having a median particle diameter in the range 5 to 15 μm. 
     
     
         38 . A metal pigment according to  claim 33  comprising metal flakes having a particle size distribution such that at least 95% by volume of the metal flakes have a particle diameter within ±25% of the median particle diameter. 
     
     
         39 . A metal pigment according to  claim 33  comprising metal flakes having a particle size distribution such that at least 95% by volume of the metal flakes have a particle diameter within ±3% of the median particle diameter. 
     
     
         40 . A metal pigment according to  claim 33  wherein the metal flakes have an aspect ratio of at least 15:1. 
     
     
         41 . A metal pigment according to  claim 33  wherein the metal flakes have an aspect ratio of about 30:1 to about 100:1. 
     
     
         42 . A metal pigment according to  claim 33  wherein the metal flakes have an aspect ratio of at least 150:1. 
     
     
         43 . A metal pigment according to  claim 33  wherein the metal flakes have a substantially circular face. 
     
     
         44 . A metal pigment according to  claim 33  which is obtainable by a jetting process comprising the steps of ejecting molten metal from a jet head, wherein the molten metal is in the form of droplets which are induced to part reliably and uniformly on egress from the nozzle entrance, and either:
 (a) collecting droplets of metal on a collecting substrate, wherein the collecting substrate comprises a solid release layer; or 
 (b) collecting droplets of metal in or on a collecting substrate and subsequently milling the collected metal droplets. 
 
     
     
         45 . A surface coating comprising a metal pigment as defined in  claim 33 . 
     
     
         46 . A surface coating according to  claim 45  which is an ink, a paint, a powder coating or a metal flake pigment paste.