Mixed-metal-neutralized-copolymer-resins for metal coating powder applications

A method of coating a metallic surface comprising the steps:

• (a) preparing a resin powder comprising at least one neutralized acid copolymer wherein the neutralized copolymer is a mixed metal salt of zinc (Zn) and a second metal (M2) that is different from Zn, wherein:
• (i) the acid copolymer is obtained by copolymerization of an alpha-olefin with an alpha-beta unsaturated carboxylic acid;
• (ii) the copolymer includes the alpha-olefin in a wt % range of from about 78% to about 86% and the carboxylic acid in a wt % range of from about 14% to about 22%, based on the total weight of the copolymer;
• (iii) the copolymer optionally includes a third comonomer in an amount of up to about 30 wt % based upon the total combined monomer weight in the copolymer;
• (iv) the copolymer has an MI in the range of from a about 20 to about 1,000 g/10 min;
• (v) the carboxylic acid group is neutralized with Zn and M2 to a combined neutralization level of from about 10 mol % to about 60 mol % of the acid;
• (vi) M2 is selected from Groups 1-13 of the Periodic Table of the Elements;
• and
• (vii) the transition metal content is at least 35%;
• (b) forming a powder having irregularly shaped particles from the resin by grinding the copolymer, the particles having a particle size in the range of from about 20 to about 500 micrometers;
• and
• (c) applying the powder to the metallic surface or a layer on said surface to form a powder coating on said surface or layer.