Styrene-free copolymers and coating compositions containing such copolymers

A food or beverage can, or a portion thereof, having a cured coating formed from an aqueous food or beverage can coating composition suitable for use in forming a food-contact coating of a metal food or beverage can, the cured coating being disposed on at least a portion of a metal substrate and wherein the coating composition comprised:

• an aqueous carrier;
• and
• a resin system dispersed in the aqueous carrier, wherein the resin system is substantially free of styrene and comprises:
• a water-dispersible polymer comprising an acrylic polymer, a polyester polymer, a polyether polymer, a polyolefin polymer, a polysilicone polymer, or a mixture or copolymer thereof;
• and
• an emulsion polymerized ethylenically unsaturated monomer component comprising:
• (iii) at least 30 wt-% of one or more alkyl (meth)acrylates;
• and
• (iv) more than 30 wt-% of one or more ethylenically unsaturated monomers having a linear or branched hydrocarbon group including at least 4 carbon atoms.

A method of coating a food or beverage can comprising applying a coating composition suitable for use in forming a food-contact coating on a metal food or beverage can to a surface of a metal substrate prior to or after forming the metal substrate into a food or beverage can or a portion thereof, wherein the coating composition comprises:

• an aqueous carrier;
• and
• a resin system dispersed in the aqueous carrier, wherein the resin system is substantially free of styrene and comprises:
• a water-dispersible polymer comprising an acrylic polymer, a polyester polymer, a polyether polymer, a polyolefin polymer, a polysilicone polymer, or a mixture or copolymer thereof;
• and
• an emulsion polymerized ethylenically unsaturated monomer component comprising:
• (i) at least 30 wt-% of one or more alkyl (meth)acrylates;
• and
• (ii) more than 30 wt-% of one or more ethylenically unsaturated monomers having a linear or branched hydrocarbon group including at least 4 carbon atoms.

A method of making a latex dispersion that is substantially free of each of:

• styrene, bisphenol A, bisphenol F, and bisphenol S, including epoxides thereof, and is also optionally substantially free of substituted styrene compounds, the method comprising:
• providing an aqueous dispersion of a water-dispersible polymer comprising an acrylic polymer, a polyester polymer, a polyether polymer, a polyolefin polymer, a polysilicone polymer, or a mixture or copolymer thereof;
• and
• emulsion polymerizing an ethylenically unsaturated monomer component in the presence of the aqueous dispersion of the water-dispersible polymer, wherein the ethylenically unsaturated monomer component comprises a mixture of monomers that includes:
• more than 30% by weight of one or more ethylenically unsaturated monomer having a four carbon or longer hydrocarbon group, and
• optionally one or more C1-C3 alkyl (meth)acrylates;
• wherein at least one alkyl methacrylate is present in the ethylenically unsaturated monomer component;
• and
• wherein alkyl (meth)acrylates constitute at least 30 wt-% of the ethylenically unsaturated monomer component.