Styrenated maleinized fatty acid glyceride copolymer for aqueous dispersed binders in solvent free ambient dry paints

An ambient dry coating composition substantially free of volatile organic coalescing solvents, the coating composition having a polymeric binder of a copolymer of a copolymerized maleinized fatty acid glyceride and ethylenically unsaturated monomer, wherein the copolymer is overpolymerized with ethylenically unsaturated monomer and free unpolymerized fatty acid glyceride does not exceed 20 percent of the copolymerized maleinized fatty acid glyceride and the copolymer comprising on a weight basis,

• between 40% and 50% copolymerized non-conjugated, unsaturated fatty acid glyceride,
• between 40% and 55% copolymerized ethylenic monomer comprising styrene, and
• between 3% and 12% copolymerized maleic anhydride, where the copolymer is produced by the process of
• (a) reacting the maleic anhydride with the fatty acid glyceride at temperatures above about 140° C. to form a maleinized fatty acid glyceride having a pendent maleic anhydride structure,
• (b) in situ copolymerizing the ethylenic monomers with the maleinized fatty acid glyceride, in the absence of water and volatile organic solvent, at temperatures between about 80° C. and 200° C., and in the presence of a peroxide initiator, the peroxide initiator at a level above the molar peroxide equivalent of 4% by weight di-tertiary butyl peroxide based on the weight of monomer copolymerized, to form a styrenated, maleinized fatty acid glyceride copolymer having anhydride groups,
• (c) reacting the anhydride groups with water or a low alkyl alcohol to form a carboxyl functional copolymer,
• (d) neutralizing the carboxyl functional copolymer with amine or ammonia to form a neutralized copolymer, and
• (e) dispersing the neutralized copolymer into water to form an aqueous dispersed copolymer.