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US 12,480,018 B2Granted
Unsaturated resins and coating compositions therefrom
AssigneeSwimc LLC
InventorsMarie Braillon-Girard, Sébastien Gibanel, Dominique Michel, Edith Barre, Matthieu Andriot
Life of this patent
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Abstract
The disclosure provides a resin having unsaturated functionality effective for self-cross linking in compositions that are at least substantially free of external cross linkers and still achieve desired performance for internal and/or external food or beverage can coating applications. Unsaturation may be provided by reactants having a carbon-carbon double bond less reactive than a carbon-carbon double bond of maleic anhydride.
Claims18
A method of applying an overprint varnish to an external surface of a food or beverage packaging article, the method comprising:
- applying a base coating layer to at least a portion of a metal substrate that has formed or is to be formed into the food or beverage packaging article;
- applying a coating composition on the base coating layer while the base coating layer is still wet to provide an overprint varnish covering at least a portion of the base coating layer;
- the coating composition includes an unsaturated polyester resin having an iodine value at least about 10, wherein at least some of the unsaturation of the polyester resin is provided by one or more unsaturated reactants having a carbon-carbon double bond less reactive than a carbon-carbon double bond of maleic anhydride;
- wherein the coating composition is substantially free of formaldehyde-based cross linkers;
- and wherein the coating composition includes one of (i) an ether group in the unsaturated polyester resin, (ii) a metal drier in the coating composition, or (iii) both an ether group in the unsaturated polyester resin and a metal drier in the coating composition;
- curing the base coating layer and overprint varnish combination to form a coated metal substrate;
- and
- wherein the dry coating weight of the overprint varnish is about 3 to about 15 g/m2.
5 more elements
Dependencies are inferred from the claim text.