Packaging coating containing water-dispersible acrylic block copolymer
AssigneeSwimc LLC
InventorsJoseph D. DeSousa, Zhilian Zhou, Kailas B. Sawant
Life of this patent
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Abstract
A food or beverage container having a body portion or an end portion that includes a metal substrate with a coating composition disposed thereon. The coating composition includes a water-dispersible acrylic linear block copolymer made by surfactant-free heterogeneous radical polymerization (“SFHRP”). The block copolymer imparts a desirable combination of flexibility and corrosion resistance to the coating composition, and the substantial absence of surfactants during polymerization contributes to other desirable properties including good blush resistance.
Claims20
A food or beverage container that includes one or more of a body portion or an end portion including a metal substrate and a cured coating disposed thereon as a cured continuous coating on an interior surface at a coating weight of about 1 to about 20 mg/in2 (msi), wherein the coating is formed from an aqueous coating composition comprising a water-dispersible acrylic linear block copolymer made by surfactant-free heterogeneous radical polymerization, wherein the copolymer has blocks having different glass transition temperatures (Tg) by at least about 50° C., and the copolymer has a number average molecular weight (Mn) of at least 75,000 Daltons and an acid number of at least 80 milligrams (mg) KOH per gram of copolymer.
A method for preparing a coated food or beverage container, or a portion thereof, the method including applying an aqueous coating composition as a cured continuous coating on an interior surface at a coating weight of about 1 to about 20 mg/in2 (msi) that includes a water-dispersible acrylic linear block copolymer made by surfactant-free heterogeneous radical polymerization to a metal substrate prior to or after forming the metal substrate into a food or beverage container or portion thereof, wherein the copolymer has blocks having different glass transition temperatures (Tg) by at least about 50° C., and the copolymer has a number average molecular weight (Mn) of at least 75,000 Daltons and an acid number of at least 80 milligrams (mg) KOH per gram of copolymer.
Dependencies are inferred from the claim text.