Multi-stage polymeric latexes, coating compositions containing such latexes, and articles coated therewith

Patent metadata

Field	Value
Publication number	US-12441817-B2
Application number	US-202418656283-A
Country	US
Kind code	B2
Filing date	May 6, 2024
Priority date	Sep 1, 2017
Publication date	Oct 14, 2025
Grant date	Oct 14, 2025

Abstract

An aqueous coating composition useful in coating a variety of substrates, including interior or exterior portions of food or beverage cans. The coating composition includes a multi-stage polymeric latex having two or more emulsion polymerized stages in an aqueous carrier liquid, wherein the latex has one or both of:
(i) a lower glass transition temperature (Tg) emulsion polymerized stage having a calculated Tg that is at least 20° C. lower than a calculated Tg of a higher Tg emulsion polymerized stage, or (ii) a gradient Tg with at least a 20° C. differential in the calculated Tg of monomers fed at the start of polymerization compared to monomers fed at the end of polymerization.

When spray-applied on the interior of a food or beverage can, the composition exhibits a global extraction result of less than 50 ppm and a metal exposure value of less than 3 mA.

First claim

The invention claimed is:

1. An aqueous interior spray beverage container coating composition comprising a multi-stage polymeric latex having two or more emulsion polymerized ethylenically unsaturated monomer stages, wherein the latex has a lower Tg emulsion polymerized stage having a calculated Tg that is at least 35° C. lower than a calculated Tg of a higher Tg emulsion polymerized stage, wherein the coating composition includes, based on total resin solids, at least 50 wt. % of the two or more emulsion polymerized stages;
wherein the coating composition includes from 15 wt. % to 25 wt % of solids, is substantially free of each of bisphenol A, bisphenol F, and bisphenol S, and includes or is derived from no more than 0.5 wt. % of acrylamide-type monomers, if any, based on the aggregate weight of polymerizable monomers employed to make the latex;
wherein the coating composition, when spray applied onto an interior of a 355 mL no. 211 two-piece drawn and ironed aluminum beverage can at 115 milligrams per can coating weight and cured at 188° C. to 199° C. (measured at the can dome) for 55 seconds exhibits:
(i) a global extraction result of less than 50 ppm,
(ii) a metal exposure of less than 3 mA on average when the can is filled with 1% NaCl in deionized water and tested pursuant to the Initial Metal Exposure test method disclosed herein,
(iii) a metal exposure of less than 3.5 mA when tested pursuant to the Metal Exposure after Drop Damage test disclosed herein, and
(iv) a measured Tg of at least 50° C.

2. The coating composition of claim 1 , wherein the coating composition, when spray applied onto an interior of a 355 mL no. 211 two-piece drawn and ironed aluminum beverage can at 115 milligrams per can coating weight and cured at 188° C. to 199° C. (measured at the can dome) for 55 seconds, exhibits a measured Tg of at least 60° C.

3. The coating composition of claim 2 , wherein the aggregate of monomers used to form the two or more emulsion polymerized stages include at least 85 wt. % of one or more (meth)acrylates.

4. The coating composition of claim 2 , wherein the latex has a higher Tg emulsion polymerized stage having a calculated Tg of greater than 60° C.

5. The coating composition of claim 1 , wherein more than 50 weight percent of the emulsion polymerized stages have a calculated Tg of at least 60° C.

6. The coating composition of claim 2 , wherein organic solvent constitutes at least 10% by weight of the aqueous carrier liquid of the coating composition.

7. The coating composition of claim 1 , wherein the coating composition, when spray applied onto an interior of a 355 mL no. 211 two-piece drawn and ironed aluminum beverage can at 115 milligrams per can coating weight and cured at 188° C. to 199° C. (measured at the can dome) for 55 seconds, exhibits a measured Tg of at least 70° C.

8. The coating composition of claim 1 , wherein the coating composition, when spray applied onto an interior of a 355 mL no. 211 two-piece drawn and ironed aluminum beverage can at 115 milligrams per can coating weight and cured at 188° C. to 199° C. (measured at the can dome) for 55 seconds, exhibits a measured Tg of at least 80° C.

9. The coating composition of claim 1 , wherein the lower Tg emulsion polymerized stage has a calculated Tg that is at least 50° C. lower than the calculated Tg of the higher Tg emulsion polymerized stage.

10. The coating composition of claim 1 , wherein the lower Tg emulsion polymerized stage has a calculated Tg that is at least 60° C. lower than the calculated Tg of the higher Tg emulsion polymerized stage.

11. The coating composition of claim 1 , wherein the weight ratio of the lower Tg emulsion polymerized stage relative to the higher Tg emulsion polymerized stage ranges from 20:80 to 70:30.

12. The coating composition of claim 1 , wherein the coating composition is not prepared using halogenated monomers.

13. The coating composition of claim 1 , wherein the monomers used to form at least one of the emulsion polymerized stages includes at least 85 wt. % of one or more (meth)acrylates.

14. The coating composition of claim 1 , wherein two or more of the emulsion polymerized stages are formed from monomers having in the aggregate a calculated Tg of at least 50° C.

15. The coating composition of claim 1 , wherein the aqueous coating composition includes, based on total resin solids, at least 60 wt. % of the two or more emulsion polymerized stages.

16. The coating composition of claim 1 , wherein the aqueous coating composition includes, based on total resin solids, at least 70 wt. % of the two or more emulsion polymerized stages.

17. The coating composition of claim 1 , wherein organic solvent constitutes at least 5% by weight of the aqueous carrier liquid of the coating composition.

18. The coating composition of claim 1 , wherein at least one of the emulsion polymerized stages is formed from monomers including a multi-ethylenically unsaturated monomer.

19. The coating composition of claim 1 , wherein the coating composition is substantially free of styrene and substituted styrene compounds.

20. The coating composition of claim 1 , wherein the coating composition does not contain any structural units derived from a bisphenol.

21. The coating composition of claim 1 , wherein the aqueous coating composition further comprises a phenoplast crosslinker.

22. The coating composition of claim 1 , wherein the coating composition, when spray applied onto an interior of a 355 mL no. 211 two-piece drawn and ironed aluminum beverage can at 115 milligrams per can coating weight and cured at 188° C. to 199° C. (measured at the can dome) for 55 seconds, is capable of passing a necking and flanging test as indicated by a change of metal exposure after necking of less than 1.0 mA.

23. An aqueous interior spray beverage container coating composition comprising a multi-stage polymeric latex having two or more emulsion polymerized ethylenically unsaturated monomer stages, wherein the latex has a lower Tg emulsion polymerized stage having a calculated Tg that is at least 40° C. lower than a calculated Tg of a higher Tg emulsion polymerized stage, wherein the coating composition includes, based on total resin solids, at least 70 wt. % of the two or more emulsion polymerized stages;
wherein the coating composition:
includes from 15 wt. % to 25 wt % of solids,
has a viscosity of from 20 to 80 seconds (Ford Cup #2, 25° C.),
is substantially free of each of bisphenol A, bisphenol F, and bisphenol S,
is not prepared using halogenated monomers, and
includes or is derived from no more than 0.5 wt. % of acrylamide-type monomers, if any, based on the aggregate weight of polymerizable monomers employed to make the latex;

wherein the coating composition, when spray applied onto an interior of a 355 mL no. 211 two-piece drawn and ironed aluminum beverage can at 115 milligrams per can coating weight and cured at 188° C. to 199° C. (measured at the can dome) for 55 seconds exhibits:
(i) a global extraction result of less than 50 ppm,
(ii) a metal exposure of less than 3 mA on average when the can is filled with 1% NaCl in deionized water and tested pursuant to the Initial Metal Exposure test method disclosed herein,
(iii) a metal exposure of less than 3.5 mA when tested pursuant to the Metal Exposure after Drop Damage test disclosed herein, and
(iv) a measured Tg of at least 70° C.

24. The coating composition of claim 23 , wherein the coat

Assignees

• Swimc Llc

Inventors

• O'Brien Robert M
• Stuetelberg Mark
• Desousa Joseph D
• Scandolari Mary Jo
• Koch Nikolaus
• Pollin Stephen
• Hussain Nusrah

Classifications

• C09D133/26

  Homopolymers or copolymers of acrylamide or methacrylamide · CPC title

• C09D133/12

  Homopolymers or copolymers of methyl methacrylate · CPC title

• C09D5/024

  characterised by the additives · CPC title

• B65D25/14

  Linings or internal coatings (of containers made by folding or erecting blanks made of paper B65D5/56 {; linings for domestic water storage heaters F24H1/183}) · CPC title

• C09D7/40

  Additives · CPC title