Multi-stage polymeric latexes, coating compositions containing such latexes, and articles coated therewith

An article that has been or will be formed into a food or beverage container or container component, the article comprising a metal substrate having on at least one surface a coating formed from a sprayable aqueous coating composition comprising:

• a resin system including a water-dispersible polymer and two or more emulsion a multi-stage polymeric latex having two or more emulsion polymerized stages in an aqueous carrier liquid, wherein the water-dispersible polymer is incorporated into the multi-stage polymeric latex, blended with the multi-stage polymeric latex, or both;
• the aqueous carrier liquid contains greater than about 5% organic solvents based on the total weight of the aqueous carrier liquid;
• and wherein the latex has one or both of:
• (i) a lower Tg emulsion polymerized stage having a calculated Tg that is at least 20° C. lower than a calculated Tg of a higher Tg emulsion polymerized stage, and wherein polymerization of the lower Tg emulsion polymerized stage is initiated before initiating polymerization of the higher Tg emulsion polymerized stage, or
• (ii) a gradient Tg with at least a 20° C. Tg differential in the calculated Tg of monomers fed at the start of polymerization compared to monomers fed at the end of polymerization.

A method for making a coated food or beverage container or container component, the method comprising the steps of:

• (a) spray-applying on an interior surface of a metal food or beverage container having a body portion and an end portion an aqueous coating composition comprising a resin system including a water-dispersible polymer and a multi-stage polymeric latex having two or more emulsion polymerized stages in an aqueous carrier liquid, wherein the water-dispersible polymer is incorporated into the multi-stage polymeric latex, blended with the multi-stage polymeric latex, or both;
• the aqueous carrier liquid contains greater than about 5% organic solvents based on the total weight of the aqueous carrier liquid;
• and wherein the latex has one or both of:
• (i) a lower Tg emulsion polymerized stage having a calculated Tg that is at least 20° C. lower than a calculated Tg of a higher Tg emulsion polymerized stage, and wherein polymerization of the lower Tg emulsion polymerized stage is initiated before initiating polymerization of the higher Tg emulsion polymerized stage, or
• (ii) a gradient Tg with at least a 20° C. Tg differential in the calculated Tg of monomers fed at the start of polymerization compared to monomers fed at the end of polymerization;
• and
• (b) curing the coating composition to form a hardened coating.