Removable closure and coating system

Patent metadata

Field	Value
Publication number	US-10486865-B2
Application number	US-201415026895-A
Country	US
Kind code	B2
Filing date	Sep 24, 2014
Priority date	Oct 2, 2013
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

The present invention provides coating systems that use polycyclic polyester resins in combination with phenolic resins. The combination of these resin materials provides a coating composition that provides cured coatings with excellent adhesion, blush resistance, stain resistance, and corrosion resistance in a single coating composition. This makes the coating compositions well suited for use to form coatings on closures used in the packaging industry for food and beverages. In many embodiments, even though PVC and BPA materials are excluded, the coating compositions provide monocoats whose performance substantially matches and even exceeds the performance of monocoats formed from PVC and BPA containing materials.

First claim

What is claimed is:

1. A method of making a removable closure for use in sealing a food or beverage container, the method comprising:
(a) providing a metal-containing substrate;
(b) providing a coating composition, said coating composition incorporating ingredients comprising:
(i) at least one polycyclic polyester resin, wherein the polycyclic polyester resin comprises first and second fused rings that share at least one atom in common; and
(ii) first and second crosslinkable, resole phenolic resins that are different from one another, the first crosslinkable, resole phenolic resin comprising a crosslinkable, alkylated resole phenolic resin; and
wherein the coating composition is substantially free of resins and resin precursors comprising covalent halogen-containing functionality, and wherein the coating composition is substantially free of resins and resin precursors incorporating bisphenol A;

(c) applying the coating composition onto at least a portion of a surface of the substrate under conditions effective to provide a dried coating having an average dry film weight of 1 to 25 grams per square meter of coated surface area;
(d) at least partially curing the applied coating composition to form a coating on the substrate;
(e) forming the coated substrate into a removable closure comprising the coating on an interior surface of the closure; and
(f) providing a gasket to at least a portion of the coating on the interior surface of the closure, wherein the gasket is adhered to the coating.

2. The method of claim 1 , wherein the polycyclic polyester resin has an acid number of less than 10.

3. The method of claim 1 , wherein the polycyclic polyester resin has a glass transition temperature greater than 50° C.

4. The method of claim 1 , wherein the polycyclic polyester resin has a glass transition temperature greater than 70° C.

5. The method of claim 1 , wherein the polycyclic polyester resin comprises one or more polycyclic groups derived from one or more ingredients comprising tricyclodecanedimethanol.

6. The method of claim 1 , wherein the step of providing the coating composition further comprises providing at least one compound comprising blocked isocyanate functionality.

7. The method of claim 6 , wherein the at least one compound comprising blocked isocyanate functionality comprises a blocked isophorone diisocyanate compound.

8. The method of claim 6 , wherein the at least one compound comprising blocked isocyanate functionality comprises a cyclohexyl moiety comprising at least two pendant blocked isocyanate groups.

9. The method of claim 1 , wherein the polycyclic polyester resin has a number average molecular weight of at least 4,000, a glass transition temperature of at least 30° C., and a hydroxyl number of less than 25.

10. The method of claim 1 , wherein the coating composition comprises 15 to 45 weight percent of at least one polycyclic polyester resin, 5 to 60 weight percent of the first and second crosslinkable, resole phenolic resins, 0 to 25 weight percent of at least one filler particle, and 20 to 70 weight percent of a solvent.

11. The method of claim 1 , wherein the coating has an average dry film weight of from 9 to 13 grams per square meter of coated surface.

12. The method of claim 1 , wherein the applied coating is a monocoat coating, and wherein the gasket is applied directly onto the monocoat coating.

13. The method of claim 1 , wherein the polycyclic polyester resin further comprises at least one bridged ring sharing three or more atoms in common with at least one of the first and second fused rings.

14. The method of claim 1 , wherein the coating composition is substantially free of polyvinyl chloride.

15. The method of claim 1 , wherein the coating composition is substantially free of mobile and bound bisphenol A, mobile and bound bisphenol F, mobile and bound bisphenol S, and mobile and bound diepoxides of any of these bisphenols.

16. The method of claim 1 , wherein the second crosslinkable, resole phenolic resin is non-alkylated.

17. The method of claim 1 , wherein the polycyclic polyester resin comprises one or more substituted and/or unsubstituted polycyclic groups selected from

wherein each Y independently is a bond that connects the polycyclic group to another portion of the resin.

18. The method of claim 1 , wherein a polycyclic group of the polycyclic polyester resin comprises a substituted or unsubstituted moiety of the formula, wherein each Y independently is a bond that connects the polycyclic group to another portion of the resin:

19. The method of claim 1 , wherein the gasket comprises a PVC resin.

20. The method of claim 1 , wherein the polycyclic polyester resin has a backbone and a plurality of polycyclic moieties are incorporated into the backbone, or a plurality of polycyclic moieties are pendant from the backbone.

21. The method of claim 1 , wherein an acidic food item is stored in the container.

22. The method of claim 1 , wherein an acidic beverage is stored in the container.

23. The method of claim 1 , wherein the fused rings share at least 2 atoms in common.

24. The method of claim 1 , wherein the second crosslinkable, resole phenolic resin, is an alkylated crosslinkable, resole phenolic resin that is different from the first crosslinkable, alkylated resole phenolic resin.

25. The method of claim 1 wherein the removable closure is subjected to retort, and the coating composition remains adhered to the substrate after retort.

Assignees

• Valspar Sourcing Inc
• Sherwin Williams Co

Inventors

• Destal Delphine
• Quereau Marie-Edith
• Michel Philippe
• Prouvost Benoit

Classifications

• B32B2435/02

  for containers · CPC title

• B65D41/023 Primary

  with integral internal sealing means · CPC title

• C09D167/02

  Polyesters derived from dicarboxylic acids and dihydroxy compounds (C09D167/06 takes precedence) · CPC title

• C08L61/12

  with polyhydric phenols · CPC title