Coating compositions for aluminum beverage cans and methods of coating same

1. A method, comprising the steps of:

receiving a coating composition that includes an emulsion polymerized latex polymer that comprises a reaction product of an ethylenically unsaturated monomer component polymerized in the presence of an aqueous dispersion of a salt of an acid- or anhydride-functional polymer, wherein the ethylenically unsaturated monomer component includes an oxirane group-containing monomer, and wherein the coating composition is made without using PVC compounds, BPA, or aromatic glycidyl ether compounds; and

spray applying the coating composition onto an interior surface of an aluminum beverage can including a body portion and a bottom end portion.

2. The method of claim 1 , wherein the oxirane group-containing monomer comprises glycidyl methacrylate, glycidyl acrylate, or a mixture of glycidyl methacrylate and glycidyl acrylate.

3. The method of claim 1 , wherein the ethylenically unsaturated monomer component includes ethyl acrylate.

4. The method of claim 1 , wherein at least 50 wt-% of the ethylenically unsaturated monomer component is used in making the latex polymer, based on the total weight of ethylenically unsaturated monomer component and salt of the acid- or anhydride-functional polymer.

5. The method of claim 1 , wherein the salt of an acid- or anhydride-functional polymer comprises a salt of an acid- or anhydride-functional polymer and a tertiary amine.

6. The method of claim 1 , wherein the acid- or anhydride-functional polymer comprises an organic-solution polymerized acid- or anhydride-functional polymer.

7. The method of claim 5 , wherein the acid- or anhydride-functional polymer comprises an organic-solution polymerized acid- or anhydride-functional polymer.

8. The method of claim 1 , wherein the salt of an acid- or anhydride-functional polymer comprises a salt of an acid- or anhydride-functional alkyd resin, a salt of an acid- or anhydride-functional polyester resin, or a salt of an acid- or anhydride-functional polyurethane resin.

9. The method of claim 1 , wherein the coating composition does not include a crosslinker.

10. The method of claim 1 , wherein the coating composition does not include a phenoplast crosslinker, an aminoplast crosslinker, or a blocked or non-blocked isocyanate crosslinker.

11. The method of claim 1 , wherein the coating composition is completely free of bound BPA and aromatic glycidyl ethers.

12. The method of claim 1 , further comprising filling the coated beverage can with a beverage product.

13. The method of claim 1 , wherein the salt of an acid- or anhydride-functional polymer comprises a salt of an acid- or anhydride-functional acrylic polymer.

14. The method of claim 13 , wherein the 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.

15. The method of claim 13 , wherein the 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.

16. The method of claim 13 , wherein the polymerizable unsaturated monomers used to generate the acid- or anhydride-functional acrylic polymer includes methacrylic acid and does not include acrylic acid.

17. The method of claim 13 , wherein the acid- or anhydride-functional monomers included in the polymerizable unsaturated monomers used to generate the acid- or anhydride-functional acrylic polymer consists of methacrylic acid.

18. The method of claim 13 , further comprising curing the coating composition to form a cured coating.

19. The method of claim 18 , wherein the cured coating exhibits a metal exposure of less than 2 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.

20. The method of claim 19 , wherein the cured coating exhibits a metal exposure of less than 2 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.

21. The method of claim 18 , wherein the cured coating exhibits a metal exposure of less than 1 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.

22. The method of claim 18 , wherein the cured coating exhibits a global extraction result of less than 50 ppm.

23. The method of claim 18 , wherein the cured coating exhibits a global extraction result of less than 10 ppm.

24. The method of claim 18 , wherein the cured coating exhibits a global extraction result of less than 1 ppm.

25. The method of claim 18 , wherein the beverage can or a portion thereof includes a dome apex and the cured coating shows no craze after the outside of the dome apex is subjected to a 12 in-lbs reverse impact.

26. The method of claim 18 , wherein the cured coating 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.

27. The method of claim 26 , wherein the coating composition does not include a crosslinker.

28. The method of claim 1 , wherein the oxirane-group containing monomer is present in an amount of 0.1 wt-% to 30 wt-%, based on the weight of the ethylenically unsaturated monomer component.

29. The method of claim 28 , wherein the oxirane-group containing monomer is present in an amount of more than 5 wt-% to 30 wt-%, based on the weight of the ethylenically unsaturated monomer component.

30. The method of claim 29 , wherein the oxirane group-containing monomer comprises glycidyl methacrylate, glycidyl acrylate, or a mixture of glycidyl methacrylate and glycidyl acrylate.

31. The method of claim 28 , wherein the oxirane-group containing monomer is present in an amount of more than 5 wt-% to 9 wt-%, based on the weight of the ethylenically unsaturated monomer component.

32. The method of claim 1 , wherein the ethylenically unsaturated monomer component includes at least 20 wt-% of a vinyl aromatic compound.

33. The method of claim 32 , wherein the ethylenically unsaturated monomer component includes butyl acrylate.

34. The method of claim 33 , wherein the ethylenically unsaturated monomer component includes from about 30 wt-% to about 55 wt-% of butyl acrylate.

35. The method of claim 32 , wherein the ethylenically unsaturated monomer component includes ethyl acrylate.

36. The method of claim 1 , wherein the ethylenically unsaturated monomer component includes at least 20 wt-% of styrene.

37. The method of claim 36 , wherein the ethylenically unsaturated monomer component includes butyl acrylate.

38. The method of claim 37 , wherein the ethylenically unsaturated monomer component includes from about 30 wt-% to about 55 wt-% of butyl acrylate.

39. The method of claim 36 , wherein the ethylenically unsaturated monomer component includes ethyl acrylate.

40. The method of claim 1 , wherein the ethylenically unsaturated monomer component includes butyl acrylate.

41. The method of claim 40 , wherein the ethylenically unsaturated monomer component includes from about 30 wt-% to about 55 wt-% of butyl acrylate.

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

43. The method of claim 42 , wherein the ethylenically unsaturated monomer component does not include any vinyl acrylamide monomers.

44. A method, comprising the steps of:

receiving a coating composition that includes an emulsion polymerized latex polymer that comprises a reaction product of an ethylenically unsaturated monomer component polymerized in the presence of an aqueous dispersion of a salt of an acid- or anhydride-functional acrylic polymer and an amine, wherein the ethylenically unsaturated monomer component includes an oxirane group-containing monomer, and wherein the coating composition is made without using PVC compounds, BPA, or aromatic glycidyl ether compounds; and

spray applying the coating composition onto an interior surface of an aluminum beverage can including a body portion and a bottom end portion.

45. The method of claim 44 , wherein the oxirane group-containing monomer comprises glycidyl methacrylate, glycidyl acrylate, or a mixture of glycidyl methacrylate and glycidyl acrylate.

46. The method of claim 44 , wherein the ethylenically unsaturated monomer component includes ethyl acrylate.

47. The method of claim 44 , wherein at least 50 wt-% of the ethylenically unsaturated monomer component is used in making the latex polymer, based on the total weight of ethylenically unsaturated monomer component and the salt of the acid- or anhydride-functional acrylic polymer and an amine.

48. The method of claim 44 , wherein the amine comprises a tertiary amine.

49. The method of claim 44 , wherein the coating composition does not include a crosslinker.

50. The method of claim 44 , wherein the coating composition does not include a phenoplast crosslinker, an aminoplast crosslinker, or a blocked or a blocked or non-blocked isocyanate crosslinker.

51. The method of claim 44 , wherein the coating composition is completely free of bound BPA and aromatic glycidyl ethers.

52. The method of claim 44 , further comprising curing the coating composition to form a cured coating.

53. The method of claim 52 , wherein the cured coating exhibits a metal exposure of less than 1 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.

54. The method of claim 52 , wherein the cured coating exhibits a global extraction result of less than 50 ppm.

55. The method of claim 52 , wherein the cured coating exhibits a global extraction result of less than 10 ppm.

56. The method of claim 52 , wherein the cured coating exhibits a global extraction result of less than 1 ppm.

57. The method of claim 52 , wherein the beverage can or a portion thereof includes a dome apex and the cured coating shows no craze after the outside of the dome apex is subjected to a 12 in-lbs reverse impact.

58. The method of claim 52 , wherein the cured coating 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.

59. The method of claim 58 , wherein the coating composition does not include a crosslinker.

60. The method of claim 52 , further comprising filling the coated beverage can with a beverage product.

61. The method of claim 44 , wherein the oxirane-group containing monomer is present in an amount of 0.1 wt-% to 30 wt-%, based on the weight of the ethylenically unsaturated monomer component.

62. The method of claim 61 , wherein the oxirane-group containing monomer is present in an amount of more than 5 wt-% to 30 wt-%, based on the weight of the ethylenically unsaturated monomer component.

63. The method of claim 62 , wherein the oxirane group-containing monomer comprises glycidyl methacrylate, glycidyl acrylate, or a mixture of glycidyl methacrylate and glycidyl acrylate.

64. The method of claim 61 , wherein the oxirane-group containing monomer is present in an amount of more than 5 wt-% to 9 wt-%, based on the weight of the ethylenically unsaturated monomer component.

65. The method of claim 44 , wherein the ethylenically unsaturated monomer component includes at least 20 wt-% of a vinyl aromatic compound.

66. The method of claim 65 , wherein the ethylenically unsaturated monomer component includes butyl acrylate.

67. The method of claim 66 , wherein the ethylenically unsaturated monomer component includes from about 30 wt-% to about 55 wt-% of butyl acrylate.

68. The method of claim 65 , wherein the ethylenically unsaturated monomer component includes ethyl acrylate.

69. The method of claim 44 , wherein the ethylenically unsaturated monomer component includes at least 20 wt-% of styrene.

70. The method of claim 69 , wherein the ethylenically unsaturated monomer component includes butyl acrylate.

71. The method of claim 69 , wherein the ethylenically unsaturated monomer component includes ethyl acrylate.

72. The method of claim 44 , wherein the ethylenically unsaturated monomer component includes butyl acrylate.

73. The method of claim 72 , wherein the ethylenically unsaturated monomer component includes from about 30 wt-% to about 55 wt-% of butyl acrylate.

74. The method of claim 44 , wherein the ethylenically unsaturated monomer component does not include acrylamide, methacrylamide, N-isobutoxymethyl acrylamide, or N-butoxymethyl acrylamide.

75. The method of claim 74 , wherein the ethylenically unsaturated monomer component does not include any vinyl acrylamide monomers.

76. The method of claim 44 , wherein the acid- or anhydride-functional acrylic polymer comprises an organic-solution polymerized acid- or anhydride-functional acrylic polymer.

77. The method of claim 76 , wherein the amine comprises a tertiary amine.

78. The method of claim 44 , wherein the 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.

79. The method of claim 78 , wherein the polymerizable unsaturated monomers used to generate the acid- or anhydride-functional acrylic polymer includes methacrylic acid and does not include acrylic acid.

80. A coated article comprising:

an aluminum beverage can including a body portion and a bottom end portion; and

a cured coating on an interior surface of the aluminum beverage can, wherein the coating is formed from a coating composition that includes an emulsion polymerized latex polymer that comprises a reaction product of an ethylenically unsaturated monomer component polymerized in the presence of an aqueous dispersion of a salt of an acid- or anhydride-functional polymer, wherein the ethylenically unsaturated monomer component includes an oxirane group-containing monomer, and wherein the coating composition is made without using PVC compounds, BPA, or aromatic glycidyl ether compounds.

81. The coated article of claim 80 , wherein the salt of the acid- or anhydride-functional polymer comprises a salt of an acid- or anhydride-functional acrylic polymer and an amine, and wherein the coating is formed from a spray applied coating composition.

82. The coated article of claim 81 , wherein the beverage can contains a beverage product.