Multi-stage polymeric latexes, coating compositions containing such latexes, and articles coated therewith
An aqueous coating composition is provided that is useful in coating a variety of substrates, including interior or exterior portions of food or beverage cans. The coating composition includes a resin system that includes a multi-stage latex. In some embodiments, the multi-stage latex is formed using a process that includes emulsion polymerizing two or more stages in the presence of an aqueous dispersion including a water-dispersible polymer. In certain preferred embodiments, the water-dispersible polymer is a polyether polymer.
1. An aqueous coating composition comprising:
a resin system including:
a water-dispersible polymer comprising a solution-polymerized acrylic polymer, a polyether polymer, a polyolefin polymer, a polyester polymer, or a mixture or copolymer thereof; and
a multi-stage polymeric latex having two or more emulsion polymerized stages in an aqueous carrier liquid, wherein the water-dispersible polymer is incorporated into the multi-stage polymeric latex, blended with the multi-stage polymeric latex, or both; the aqueous coating composition is a sprayable composition for a food or beverage container; and wherein the latex has 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; and
wherein the coating composition is substantially free of each of bisphenol A, bisphenol F, and bisphenol S.
2. The coating composition of claim 1 , wherein the two or more emulsion polymerized stages are emulsion polymerized in the presence of the water-dispersible polymer.
3. The coating composition of claim 2 , wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 50:50.
4. The coating composition of claim 3 , wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 40:60.
5. The coating composition of claim 4 , wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 30:70.
6. The coating composition of claim 3 , wherein the water-dispersible polymer has an acid number from 40 to 200 mg KOH per gram.
7. An aqueous coating composition comprising:
a resin system including:
a water-dispersible polymer comprising a solution-polymerized acrylic polymer, a polyether polymer, a polyolefin polymer, a polyester polymer, or a mixture or copolymer thereof; and
a multi-stage polymeric latex having two or more emulsion polymerized stages in an aqueous carrier liquid;
wherein the two or more emulsion polymerized stages are emulsion polymerized in the presence of the water-dispersible polymer;
wherein the water-dispersible polymer is incorporated into the multi-stage polymeric latex, blended with the multi-stage polymeric latex, or both; and
wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 50:50;
wherein the latex has a gradient Tg;
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; and
wherein the aqueous coating composition is a sprayable composition for a food or beverage container; and
wherein the coating composition is substantially free of each of bisphenol A, bisphenol F, and bisphenol S.
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:
(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, and
(iii) a metal exposure of less than 10 mA when tested pursuant to the Metal Exposure after Drop Damage test disclosed herein.
9. The coating composition of claim 4 , 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, and
(iii) a metal exposure of less than 3.5 mA when tested pursuant to the Metal Exposure after Drop Damage test disclosed herein.
10. The coating composition of claim 8 , 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 lower sidewall adhesion rating value of 9 or 10 after retort in 2% citric acid under pressure at 121° C. and tested according to ASTM D 3359-Test Method B.
11. The coating composition of claim 8 , 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.
12. The coating composition of claim 3 , wherein the resin system does not include and is not derived from any acrylamide-type monomers.
13. The coating composition of claim 1 , wherein the coating composition does not contain formaldehyde or formaldehyde-containing compounds.
14. An aqueous coating composition comprising:
a resin system including:
a water-dispersible polymer having an acid number of at least 40 mg KOH per gram and comprising a solution-polymerized acrylic polymer, a polyether polymer, a polyolefin polymer, a polyester polymer, or a mixture or copolymer thereof;
and a multi-stage polymeric latex having two or more emulsion polymerized stages, wherein the two or more emulsion polymerized stages are emulsion polymerized in the presence of the water-dispersible polymer, and wherein the latex has 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; and
an aqueous carrier liquid that includes at least 5 wt-% of organic solvent; and
wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 50:50; and
wherein the coating composition is an inside spray beverage can coating composition; is substantially free of each of bisphenol A, bisphenol F, and bisphenol S; and has a total solids weight of about 15 to about 25%, based on the total weight of the coating composition.
15. The coating composition of claim 14 , 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 lower sidewall adhesion rating value of 9 or 10 after retort in 2% citric acid under pressure at 121° C. and tested according to ASTM D 3359-Test Method B.
16. The coating composition of claim 14 , wherein the resin system does not include and is not derived from any acrylamide-type monomers.
17. The coating composition of claim 14 , wherein the coating composition does not contain formaldehyde or formaldehyde-containing compounds.
18. An aqueous coating composition comprising:
a resin system including:
a water-dispersible polymer comprising a solution-polymerized acrylic polymer, a polyether polymer, a polyolefin polymer, a polyester polymer, or a mixture or copolymer thereof; and
a multi-stage polymeric latex having two or more emulsion polymerized stages in an aqueous carrier liquid, wherein the water-dispersible polymer is incorporated into the multi-stage polymeric latex, blended with the multi-stage polymeric latex, or both; the aqueous coating composition is a sprayable composition for a food or beverage container; and wherein the latex has one or both of:
(i) a lower 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; and
wherein the coating composition is substantially free of each of bisphenol A, bisphenol F, and bisphenol S; and
wherein the coating composition does not include styrene.
19. The coating composition of claim 18 , wherein the aqueous carrier liquid contains greater than about 5% organic solvent based on the total weight of the aqueous carrier liquid.
20. The coating composition of claim 18 , wherein the two or more emulsion polymerized stages are emulsion polymerized in the presence of the water-dispersible polymer.
21. The coating composition of claim 20 , wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 50:50.
22. The coating composition of claim 21 , wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 40:60.
23. The coating composition of claim 22 , wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 30:70.
24. The coating composition of claim 21 , wherein the water-dispersible polymer has an acid number from 40 to 200 mg KOH per gram.
25. The coating composition of claim 21 , 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 the higher Tg emulsion polymerized stage.
26. The coating composition of claim 18 , wherein more than 50 weight percent of the emulsion polymerized stages have a calculated Tg of at least 40° C.
27. The coating composition of claim 18 , 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, and
(iii) a metal exposure of less than 10 mA when tested pursuant to the Metal Exposure after Drop Damage test disclosed herein.
28. The coating composition of claim 22 , 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, and
(iii) a metal exposure of less than 3.5 mA when tested pursuant to the Metal Exposure after Drop Damage test disclosed herein.
29. The coating composition of claim 27 , 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 lower sidewall adhesion rating value of 9 or 10 after retort in 2% citric acid under pressure at 121° C. and tested according to ASTM D 3359-Test Method B.
30. The coating composition of claim 26 , 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.
31. The coating composition of claim 21 , wherein the resin system does not include and is not derived from any acrylamide-type monomers.
32. The coating composition of claim 18 , wherein the coating composition does not contain formaldehyde or formaldehyde-containing compounds.
33. An aqueous coating composition comprising:
a resin system including:
a water-dispersible polymer having an acid number of at least 40 mg KOH per gram and comprising a solution-polymerized acrylic polymer, a polyether polymer, a polyolefin polymer, a polyester polymer, or a mixture or copolymer thereof;
and a multi-stage polymeric latex having two or more emulsion polymerized stages, wherein the two or more emulsion polymerized stages are emulsion polymerized in the presence of the water-dispersible polymer, and wherein the latex has a lower Tg emulsion polymerized stage having a calculated Tg that is at least 30° C. lower than a calculated Tg of a higher Tg emulsion polymerized stage; and
an aqueous carrier liquid that includes at least 5 wt-% of organic solvent; and
wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 50:50; and
wherein the coating composition is an inside spray beverage can coating composition; is substantially free of each of bisphenol A, bisphenol F, and bisphenol S; and has a total solids weight of about 15 to about 25%, based on the total weight of the coating composition; and
wherein the coating composition does not include styrene.
34. The coating composition of claim 33 , wherein more than 50 weight percent of the emulsion polymerized stages have a calculated Tg of at least 50° C.
35. The coating composition of claim 33 , 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 lower sidewall adhesion rating value of 9 or 10 after retort in 2% citric acid under pressure at 121° C. and tested according to ASTM D 3359-Test Method B.
36. The coating composition of claim 33 , wherein the resin system does not include and is not derived from any acrylamide-type monomers.
37. The coating composition of claim 33 , wherein the coating composition does not contain formaldehyde or formaldehyde-containing compounds.
38. An aqueous coating composition comprising:
a resin system including:
a water-dispersible polymer comprising a solution-polymerized acrylic polymer, a polyether polymer, a polyolefin polymer, a polyester polymer, or a mixture or copolymer thereof; and
a multi-stage polymeric latex having two or more emulsion polymerized stages in an aqueous carrier liquid, wherein the water-dispersible polymer is incorporated into the multi-stage polymeric latex, blended with the multi-stage polymeric latex, or both; the aqueous coating composition is a sprayable composition for a food or beverage container; and wherein the latex has one or both of:
(i) a lower 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; and
wherein the coating composition is substantially free of each of bisphenol A, bisphenol F, and bisphenol S; and
wherein the coating composition comprises a beta-hydroxyalkyl-amide crosslinker.
39. The coating composition of claim 38 , wherein the aqueous carrier liquid contains greater than about 5% organic solvent based on the total weight of the aqueous carrier liquid.
40. The coating composition of claim 38 , wherein the two or more emulsion polymerized stages are emulsion polymerized in the presence of the water-dispersible polymer.
41. The coating composition of claim 40 , wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 50:50.
42. The coating composition of claim 41 , wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 40:60.
43. The coating composition of claim 42 , wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 30:70.
44. The coating composition of claim 41 , wherein the water-dispersible polymer has an acid number from 40 to 200 mg KOH per gram.
45. The coating composition of claim 41 , 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 the higher Tg emulsion polymerized stage.
46. The coating composition of claim 38 , wherein more than 50 weight percent of the emulsion polymerized stages have a calculated Tg of at least 40° C.
47. The coating composition of claim 38 , 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, and
(iii) a metal exposure of less than 10 mA when tested pursuant to the Metal Exposure after Drop Damage test disclosed herein.
48. The coating composition of claim 42 , 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, and
(iii) a metal exposure of less than 3.5 mA when tested pursuant to the Metal Exposure after Drop Damage test disclosed herein.
49. The coating composition of claim 47 , 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 lower sidewall adhesion rating value of 9 or 10 after retort in 2% citric acid under pressure at 121° C. and tested according to ASTM D 3359-Test Method B.
50. The coating composition of claim 46 , 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.
51. The coating composition of claim 41 , wherein the resin system does not include and is not derived from any acrylamide-type monomers.
52. The coating composition of claim 38 , wherein the coating composition does not contain formaldehyde or formaldehyde-containing compounds.
53. An aqueous coating composition comprising:
a resin system including:
a water-dispersible polymer having an acid number of at least 40 mg KOH per gram and comprising a solution-polymerized acrylic polymer, a polyether polymer, a polyolefin polymer, a polyester polymer, or a mixture or copolymer thereof;
and a multi-stage polymeric latex having two or more emulsion polymerized stages, wherein the two or more emulsion polymerized stages are emulsion polymerized in the presence of the water-dispersible polymer, and wherein the latex has a lower Tg emulsion polymerized stage having a calculated Tg that is at least 30° C. lower than a calculated Tg of a higher Tg emulsion polymerized stage; and
an aqueous carrier liquid that includes at least 5 wt-% of organic solvent; and
wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 50:50; and
wherein the coating composition is an inside spray beverage can coating composition; is substantially free of each of bisphenol A, bisphenol F, and bisphenol S; and has a total solids weight of about 15 to about 25%, based on the total weight of the coating composition; and
wherein the coating composition comprises a beta-hydroxyalkyl-amide crosslinker.
54. The coating composition of claim 53 , wherein more than 50 weight percent of the emulsion polymerized stages have a calculated Tg of at least 50° C.
55. The coating composition of claim 53 , 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 lower sidewall adhesion rating value of 9 or 10 after retort in 2% citric acid under pressure at 121° C. and tested according to ASTM D 3359-Test Method B.
56. The coating composition of claim 53 , wherein the resin system does not include and is not derived from any acrylamide-type monomers.
57. The coating composition of claim 53 , wherein the coating composition does not contain formaldehyde or formaldehyde-containing compounds.
58. An aqueous coating composition comprising:
a resin system including:
a water-dispersible polymer comprising at least one of an aromatic polyether polymer and a polyether-acrylate copolymer; and
a multi-stage polymeric latex having two or more emulsion polymerized stages in an aqueous carrier liquid, wherein the water-dispersible polymer is incorporated into the multi-stage polymeric latex, blended with the multi-stage polymeric latex, or both; the aqueous coating composition is a sprayable composition for a food or beverage container; and wherein the latex has one or both of:
(i) a lower 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; and
wherein the coating composition is substantially free of each of bisphenol A, bisphenol F, and bisphenol S.
59. The coating composition of claim 58 , wherein the aqueous carrier liquid contains greater than about 5% organic solvent based on the total weight of the aqueous carrier liquid.
60. The coating composition of claim 58 , wherein the two or more emulsion polymerized stages are emulsion polymerized in the presence of the water-dispersible polymer.
61. The coating composition of claim 60 , wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 50:50.
62. The coating composition of claim 61 , wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 40:60.
63. The coating composition of claim 62 , wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 30:70.
64. The coating composition of claim 58 , wherein the water-dispersible polymer comprises a polyether polymer formed from reactants including (i) an extender and (ii) a diepoxide of: an aromatic diol, an aromatic diacid, an aliphatic diol, an aliphatic diacid, a cycloaliphatic diol, a cycloaliphatic diacid, or a combination thereof.
65. The coating composition of claim 61 , wherein the water-dispersible polymer has an acid number from 40 to 200 mg KOH per gram.
66. The coating composition of claim 61 , 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 the higher Tg emulsion polymerized stage.
67. The coating composition of claim 58 , wherein more than 50 weight percent of the emulsion polymerized stages have a calculated Tg of at least 40° C.
68. The coating composition of claim 58 , 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, and
(iii) a metal exposure of less than 10 mA when tested pursuant to the Metal Exposure after Drop Damage test disclosed herein.
69. The coating composition of claim 62 , 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, and
(iii) a metal exposure of less than 3.5 mA when tested pursuant to the Metal Exposure after Drop Damage test disclosed herein.
70. The coating composition of claim 68 , 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 lower sidewall adhesion rating value of 9 or 10 after retort in 2% citric acid under pressure at 121° C. and tested according to ASTM D 3359-Test Method B.
71. The coating composition of claim 67 , 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.
72. The coating composition of claim 61 , wherein the resin system does not include and is not derived from any acrylamide-type monomers.
73. The coating composition of claim 58 , wherein the coating composition does not contain formaldehyde or formaldehyde-containing compounds.
74. An aqueous coating composition comprising:
a resin system including:
a water-dispersible polymer having an acid number of at least 40 mg KOH per gram and comprising at least one of an aromatic polyether polymer and a polyether-acrylate copolymer;
and a multi-stage polymeric latex having two or more emulsion polymerized stages, wherein the two or more emulsion polymerized stages are emulsion polymerized in the presence of the water-dispersible polymer, and wherein the latex has a lower Tg emulsion polymerized stage having a calculated Tg that is at least 30° C. lower than a calculated Tg of a higher Tg emulsion polymerized stage; and
an aqueous carrier liquid that includes at least 5 wt-% of organic solvent; and
wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 50:50; and
wherein the coating composition is an inside spray beverage can coating composition; is substantially free of each of bisphenol A, bisphenol F, and bisphenol S; and has a total solids weight of about 15 to about 25%, based on the total weight of the coating composition.
75. The coating composition of claim 74 , wherein more than 50 weight percent of the emulsion polymerized stages have a calculated Tg of at least 50° C.
76. The coating composition of claim 74 , 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 lower sidewall adhesion rating value of 9 or 10 after retort in 2% citric acid under pressure at 121° C. and tested according to ASTM D 3359-Test Method B.
77. The coating composition of claim 74 , wherein the resin system does not include and is not derived from any acrylamide-type monomers.
78. The coating composition of claim 74 , wherein the coating composition does not contain formaldehyde or formaldehyde-containing compounds.
79. An aqueous coating composition comprising:
a resin system including:
a water-dispersible polymer comprising a solution-polymerized acrylic polymer, a polyether polymer, a polyolefin polymer, a polyester polymer, or a mixture or copolymer thereof; and
a multi-stage polymeric latex having two or more emulsion polymerized stages in an aqueous carrier liquid, wherein the water-dispersible polymer is incorporated into the multi-stage polymeric latex, blended with the multi-stage polymeric latex, or both; the aqueous coating composition is a sprayable composition for a food or beverage container; and wherein the latex has one or both of:
(i) a lower 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; and
wherein the coating composition is substantially free of each of bisphenol A, bisphenol F, and bisphenol S; and
wherein polymerization of the lower Tg emulsion polymerized stage is initiated before initiating polymerization of the higher Tg emulsion polymerized stage.
80. An aqueous coating composition comprising:
a resin system including:
a water-dispersible polymer having an acid number of at least 40 mg KOH per gram and comprising a solution-polymerized acrylic polymer, a polyether polymer, a polyolefin polymer, a polyester polymer, or a mixture or copolymer thereof;
and a multi-stage polymeric latex having two or more emulsion polymerized stages, wherein the two or more emulsion polymerized stages are emulsion polymerized in the presence of the water-dispersible polymer, and wherein the latex has a lower Tg emulsion polymerized stage having a calculated Tg that is at least 30° C. lower than a calculated Tg of a higher Tg emulsion polymerized stage; and
an aqueous carrier liquid that includes at least 5 wt-% of organic solvent; and
wherein the weight ratio of water-dispersible polymer to emulsion polymerized stages is less than 50:50; and
wherein the coating composition is an inside spray beverage can coating composition; is substantially free of each of bisphenol A, bisphenol F, and bisphenol S; and has a total solids weight of about 15 to about 25%, based on the total weight of the coating composition; and
wherein polymerization of the lower Tg emulsion polymerized stage is initiated before initiating polymerization of the higher Tg emulsion polymerized stage.