Coating composition including an unsaturated polymer
View Patent ↗A coating composition is described. The coating composition preferably includes an unsaturated polymer such as, for example, an unsaturated polyester polymer; an ether component including one or more ether groups; and an optional liquid carrier. In preferred embodiments, the unsaturated polymer preferably has an iodine value of at least 10. The coating composition is useful in coating a variety of substrates, including planar metal substrates.
1. A method comprising:
providing a thermally crosslinkable coating composition comprising:
at least 5% of an unsaturated polymer having an iodine value of at least 10, based on the total weight of nonvolatile material in the coating composition,
an ether component including one or more ether groups, and
a liquid carrier;
applying the coating composition to at least a portion of a planar metal substrate; and
heating the coated metal substrate to a peak metal temperature of at least 350° F. to form a crosslinked coating.
2. The method of claim 1 , wherein the coating composition includes an efficacious amount of the ether component.
3. The method of claim 1 , wherein the unsaturated polymer comprises a polyamide, a polycarbonate, a polyester, a polyether, a polyurea, a copolymer thereof, or a mixture thereof.
4. The method of claim 1 , wherein the coating composition includes at least 50 weight percent of the unsaturated polymer, based on the total weight of nonvolatile material in the coating composition.
5. The method of claim 1 , wherein the unsaturated polymer has an iodine value of at least 20.
6. The method of claim 1 , wherein the unsaturated polymer comprises a polyester polymer.
7. The method of claim 1 , wherein the ether component comprises a second polymer that includes the one or more ether groups.
8. The method of claim 1 , wherein the ether component comprises tripropylene glycol, a structural unit derived from tripropylene glycol, or a combination thereof.
9. The method of claim 1 , wherein the unsaturated polymer includes one or more aliphatic carbon-carbon double bonds that comprise a vinylic double bond, a conjugated double bond, a double bond present in a strained ring group, a double bond present in an unsaturated polycyclic group, or a combination thereof.
10. The method of claim 1 , wherein the coating composition is applied to a food-contact surface of the planar metal substrate.
11. The method of claim 1 , wherein the planar metal substrate comprises metal coil.
12. The method of claim 1 , wherein the coating composition is a water-based coating composition that may optionally include organic solvent.
13. The method of claim 1 , wherein the unsaturated polymer includes the ether component.
14. The method of claim 13 , wherein the unsaturated polymer includes at least 1% by weight of ether oxygen.
15. The method of claim 1 , wherein the ether component comprises a low-molecular-weight organic compound that includes the one or more ether groups.
16. The method of claim 15 , wherein the low-molecular-weight organic compound is a volatile organic compound that includes two or more ether groups.
17. The method of claim 1 , wherein the unsaturated polymer includes one or more segments derived from an unsaturated polybutadiene compound.
18. The method of claim 17 , wherein the unsaturated polymer is formed from ingredients including, based on total non-volatiles, at least 5% by weight of the unsaturated polybutadiene compound.
19. A coated article formed using the method of claim 1 .
20. The coated article of claim 19 , wherein the coated article comprises a food or beverage container or a portion thereof.
21. A composition, comprising:
a thermally crosslinkable coating composition, including:
at least 20% by weight of an unsaturated polymer having an iodine value of at least 10, based on the total weight of nonvolatile material in the coating composition;
an efficacious amount of an ether component including one or more ether groups; and
a liquid carrier that includes an amount of organic solvent that constitutes at least 15% by weight of the coating composition.
22. The coating composition of claim 21 , wherein the unsaturated polymer comprises a polyester polymer.
23. The coating composition of claim 21 , wherein the unsaturated polymer comprises a polyamide, a polycarbonate, a polyester, a polyether, a polyurea, a copolymer thereof, or a mixture thereof.
24. The composition of claim 21 , wherein the coating composition, when applied at a dry film weight of 7 milligrams per square inch directly to 0.0082 inch thick 5182 (alloy) aluminum sheet substrate and the coated metal substrate is heated for 21 seconds in a 500° F. oven to a peak metal temperature of 450° F., forms a coating having a pencil hardness of at least 2H.
25. The coating composition of claim 24 , wherein the cured coating composition exhibits a pencil hardness of at least 2H when any optional external crosslinker, if present, is omitted from the coating composition.