Coating compositions for aluminum beverage cans and methods of coating same

Patent metadata

Field	Value
Publication number	US-9862854-B2
Application number	US-201615205490-A
Country	US
Kind code	B2
Filing date	Jul 8, 2016
Priority date	Oct 20, 2004
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

A coating composition for a food or beverage can that includes an emulsion polymerized latex polymer formed by combining an ethylenically unsaturated monomer component with an aqueous dispersion of a water-dispersible polymer.

First claim

What is claimed is:

1. An inside spray beverage can coating composition, comprising an emulsion polymerized latex polymer prepared by emulsion polymerizing an ethylenically unsaturated monomer component in the presence of an aqueous dispersion of a salt of an organic-solution polymerized acid- or anhydride-functional acrylic polymer and a tertiary amine;
wherein:
the salt of the organic-solution polymerized acid- or anhydride-functional acrylic polymer comprises more than 15 wt-% acid- or anhydride-functional monomers, based on the weight of polymerizable unsaturated monomer used to generate the acid-or anhydride-functional acrylic polymer; and
the ethylenically unsaturated monomer component includes an alkyl (meth)acrylate, a vinyl aromatic compound and an oxirane-group containing monomer;
the inside spray beverage can coating composition is substantially free of mobile and bound bisphenol A;
the inside spray beverage can coating composition, when spray applied onto an interior of a 12 ounce two-piece drawn and ironed aluminum beverage can at 120 to 130 milligrams per can coating weight and cured at 188° C. to 199° C. (measured at the can dome) for 30 seconds, exhibits:
(i) a global extraction result of less than 50 ppm; and
(ii) a metal exposure of less than 3 mA on average when the can is filled with 1% NaCI in deionized water and tested pursuant to the Initial Metal Exposure test method disclosed herein; and

the inside spray beverage can coating composition is made without using PVC compounds.

2. The coating composition of claim 1 , wherein the ethylenically unsaturated monomer component comprises at least 20 wt-% of vinyl aromatic compound.

3. The coating composition of claim 1 , wherein the ethylenically unsaturated monomer component comprises at least 20 wt-% of styrene.

4. The coating composition of claim 1 , wherein the ethylenically unsaturated monomer component includes ethyl acrylate.

5. The coating composition of claim 1 , wherein the ethylenically unsaturated monomer component includes ethyl acrylate, styrene, and glycidyl methacrylate.

6. The coating composition of claim 1 , wherein the coating composition includes a phenoplast crosslinker.

7. The coating composition of claim 1 , wherein the ethylenically unsaturated monomer component does not include vinyl acrylamides or vinyl methacrylamides.

8. The coating composition of claim 1 , wherein the organic-solution polymerized acid- or anhydride- functional acrylic polymer has a number average molecular weight of 1,500 to 50,000.

9. The coating composition of claim 1 , wherein the salt of the organic-solution polymerized acid- or anhydride-functional acrylic polymer comprises more than 30 wt-% acid- or anhydride-functional monomers, based on the weight of polymerizable unsaturated monomer used to generate the acid-or anhydride-functional acrylic polymer.

10. The coating composition of claim 1 , wherein the polymerizable unsaturated monomers used to generate the organic-solution polymerized acid- or anhydride-functional acrylic polymer includes methacrylic acid and does not include acrylic acid.

11. The coating composition of claim 1 , wherein the tertiary amine comprises triethyl amine or dimethyl ethanol amine.

12. The coating composition of claim 1 , wherein at least 40 wt-% of the ethylenically unsaturated monomer component comprises one or more monomers selected from alkyl acrylates and methacrylates.

13. The coating composition of claim 1 , wherein the coating composition exhibits a global extraction result of less than 10 ppm.

14. The coating composition of claim 1 , wherein the coating composition exhibits a metal exposure of less than 2 mA.

15. The coating composition of claim 1 , wherein the coating composition, when spray applied onto an interior of a 12 ounce two-piece drawn and ironed aluminum beverage can at 120 to 130 milligrams per can coating weight and cured at 188° C. to 199° C. (measured at the can dome) for 30 seconds, shows no craze after the outside of the dome apex of the can is subjected to a 12 in-lbs reverse impact.

16. The coating composition of claim 1 , wherein the coating composition, when spray applied onto an interior of a 12 ounce two-piece drawn and ironed aluminum beverage can at 120 to 130 milligrams per can coating weight and cured at 188° C. to 199° C. (measured at the can dome) for 30 seconds, exhibits no adhesion failure when tested pursuant to ASTM D-3359-Test method B after retort in deionized water for 90 minutes at a heat of 121° C. and a corresponding pressure.

17. The coating composition of claim 1 , wherein the coating composition, when spray applied onto an interior of a 12 ounce two-piece drawn and ironed aluminum beverage can at 120 to 130 milligrams per can coating weight and cured at 188° C. to 199° C. (measured at the can dome) for 30 seconds, gives a metal exposure of less than 3,5 mA when tested pursuant to the Metal Exposure after Drop Damage test disclosed herein.

18. The coating composition of claim 1 , wherein the oxirane-group containing monomer (i) comprises glycidyl methacrylate, glycidyl acrylate, or a mixture of glycidyl methacrylate and glycidyl acrylate and (ii) is present in an amount of 0.1 wt-% to 30 wt-%, based on the weight of the ethylenically unsaturated monomer component.

19. The coating composition of claim 18 , wherein at least 60 wt-% of the ethylenically unsaturated monomer component is used in making the latex polymer, based on the total weight of the ethylenically unsaturated monomer component and the salt of the organic-solution polymerized acid- or anhydride-functional acrylic polymer.

20. The coating composition of claim 18 , wherein the organic-solution polymerized acid- or anhydride-functional acrylic polymer has an acid number of at least 100.

21. The coating composition of claim 1 , wherein the ethylenically unsaturated monomer component does not include acrylamide, methacrylamide, N-isobutoxymethyl acrylamide, or N-butoxymethyl acrylamide.

22. The coating composition of claim 21 , wherein the emulsion polymerized latex polymer is substantially free of bound aromatic glycidyl ether compounds.

23. The coating composition of claim 1 , wherein at least 25 wt-% of the ethylenically unsaturated monomer component is used in making the latex polymer, based on the total weight of the ethylenically unsaturated monomer component and the salt of the organic-solution polymerized acid- or anhydride-functional acrylic polymer.

24. The coating composition of claim 23 , wherein at least 15 wt-% of the salt of the organic-solution polymerized acid- or anhydride-functional acrylic polymer is used in making the latex polymer, based on the total weight of the ethylenically unsaturated monomer component and the salt of the organic-solution polymerized acid- or anhydride-functional acrylic polymer.

25. An inside spray beverage can coating composition, comprising:
an emulsion polymerized latex polymer that is substantially free of bound hisphenol A and bound aromatic glycidyl ether compounds and is prepared by emulsion polymerizing an ethylenically unsaturated monomer component in the presence of an aqueous dispersion of a salt of an organic-solution polymerized acid- or anhydride-functional acrylic polymer and a tertiary amine, wherein the ethylenically unsaturated monomer component includes an alkyl (meth)acrylate, a glycidyl ester of an alpha, beta-ethylenically unsaturated acid or anhydride, a

Assignees

• Valspar Sourcing Inc

Inventors

• O'Brien Robert M
• Rardon Daniel E
• Spynda Rachael Ann
• Bartley George K
• Evans Richard H

Classifications

• Y10T428/31688

  Next to aldehyde or ketone condensation product · CPC title

• Y10T428/31681

  Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.] · CPC title

• B32B15/20

  comprising aluminium or copper {(B32B15/016 and B32B15/017 take precedence)} · CPC title

• C08F265/04

  on to polymers of esters · CPC title

• C08F291/00

  Macromolecular compounds obtained by polymerising monomers on to macromolecular compounds according to more than one of the groups C08F251/00 - C08F289/00 · CPC title