Patent No. U.S. 7,736,694 B2
Dupont Polymer Powders has received a patent for a process of preparation of an antimicrobial powder coating composition comprised of the steps of transforming a natural antimicrobial agent into a salt-form and micronizing the resulting antimicrobial salt into powder,  mixing at least one of the natural antimicrobial salt together with at least one amino-reactive thermoplastic binder resin, subjecting the mixture to a melt compounding process at a temperature in a range of 80° C to 230° C, at a residence time period in a range of 5 to 60 seconds, using at least one co-rotating twin-screw extruder with a soft screw design having conveying elements offering a high D/d ratio and having mixing forward kneading block elements, cooling the extrudate and micronizing into powder particles.