Method for manufacture of lamellar metal particles

摘要

A method for converting spherical or amorphous metal particles into lamellar flakes that promote improved adhesive and cohesive characteristics when incorporated into coating compositions. The metal flakes produced exhibit properties compatible with binder chemistries such as isocyanates, titanates, titanate hybrids and are suitable for use in conjunction with advanced top coating techniques, such as electrodeposition. The particles produced by the method may be used in coatings and may exhibit improved substrate adhesion and improved cohesion characteristics when used in conjunction with an electrodeposition top coat.

主权项

1. A method of producing lamellar metal particles in a ball mill, wherein the ball mill comprises an internal mill chamber and further wherein the internal mill chamber contains an amount of grinding media having a mass, the method comprising the steps of:
(i) adding an amount of a metal charge having a mass that is between about 2% and about 12% of the mass of the grinding media to the internal mill chamber; (ii) adding an amount of a milling lubricant that is between about 0.75% and about 3% of the mass of the metal charge to the internal mill chamber; (iii) adding an amount of an anti-welding additive that is between about 0.15% and about 3.5% of the mass of the metal charge to the internal mill chamber; (iv) dry milling the metal charge by operating the mill at between about 14 and about 45 rpm for between about 6 and about 18 hours; (v) providing a mill chamber temperature of between about 140° F. and about 380° F.; and (vi) removing a metal flake product from the mill chamber, wherein the metal flake product comprises lamellar particles ranging in size from between about 1 and about 110 microns in major dimension.