Polyester-based coating composition for metal substrates
AssigneeThe Sherwin-Williams Company
InventorsBenoit Prouvost, Paul Stenson
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Abstract
The present invention provides novel packaging articles, e.g., food and beverage cans, having a novel coating composition applied to at least a portion of a surface thereon. In preferred embodiments, the coating composition includes at least a film-forming amount of a copolyester resin having a backbone that includes one or more soft segments and a plurality of hard segments. The copolyester resin preferably has a glass transition temperature from about from about 10° C. to about 50° C. The present invention also provides a method for making coated articles.
Claims32
A water-based beverage can coating composition comprising:
- a water-based carrier fluid;
- one or more water-dispersible polymers obtained by grafting acid-functional ethylenically unsaturated monomers to a polyester polymer to form a polyester-acrylic copolymer, the polyester polymer derived from reactants that include one or more polyacid molecules, one or more polyol molecules, and one or more unsaturated monomers having reactive groups capable of participating in a step-growth reaction;
- wherein at least a portion of the acid-functional groups of the acid-functional ethylenically unsaturated monomers are neutralized with a base to provide the water dispersiblity;
- and
- an effective amount of a lubricity additive to impart lubricity to planar coated metal surfaces.
An article comprising
- a riveted beverage can end;
- a cured coating applied on at least a portion of the riveted beverage can end;
- the cured coating formed from a water-based coating composition including one or more water-dispersible polymers obtained by grafting acid-functional ethylenically unsaturated monomers to a polyester polymer to form a polyester-acrylic copolymer, the polyester polymer formed from reactants that include one or more polyacid molecules, one or more polyol molecules, and one or more unsaturated monomers having reactive groups capable of participating in a step-growth reaction;
- wherein at least a portion of the acid-functional groups of the acid-functional ethylenically unsaturated monomers are neutralized with a base to provide the water dispersiblity;
- and wherein the coating composition includes an effective amount of a lubricity additive to impart lubricity to planar coated metal surfaces.
A water-based beverage can coating composition for riveted can ends, the coating composition comprising:
- a water-based carrier fluid;
- one or more water-dispersible polymers obtained by grafting acid-functional ethylenically unsaturated monomers to a polyester polymer form a polyester-acrylic copolymer, the polyester polymer derived from reactants that include one or more of cyclohexane dimethanol, trimethylolpropane, isophthalic acid, terephathlic acid, fatty acid dimers, and maleic anhydride;
- wherein at least a portion of the acid-functional groups of the acid-functional ethylenically unsaturated monomers are neutralized with a tertiary amine to provide the water dispersiblity;
- and
- an effective amount of a lubricity additive to impart lubricity to planar coated metal surfaces.
Dependencies are inferred from the claim text.