Fluoropolymer coating compositions comprising amine curing agents, coated substrates and related methods

1. A composition comprising

at least one fluoropolymer, wherein the fluoropolymer comprises cure sites and at least 90% by weight based on the total weight of the fluoropolymer of polymerized units derived from perfluorinated monomers selected from tetrafluoroethene (TFE) and one or more unsaturated perfluorinated alkyl ethers;

solvent comprising a branched, partially fluorinated ether and wherein the partially fluorinated ether corresponds to the formula:

Rf—O—R

wherein Rf is selected from perfluorinated and partially fluorinated alkyl or (poly)ether groups and R is selected from partially fluorinated and non-fluorinated alkyl groups; and

a curing agent comprising at least one amine group and at least one organosilane group.

2. The composition of claim 1 wherein the unsaturated perfluorinated alkyl ether has the general formula

R f —O—(CF 2 ) n —CF═CF 2

wherein n is 1 or 0 and R f is a perfluoroalkyl or perfluoroether group.

3. The composition of claim 1 wherein the compound is an amino organosilane ester compound or ester equivalent.

4. The composition of claim 1 wherein the compound comprises a blocked amine group.

5. The composition of claim 1 wherein the composition further comprises an alkoxy silane compound that lacks at least one amine groups.

6. The composition of claim 1 wherein the composition comprises 0.01 to 25% by weight of the fluoropolymer based on the weight of the total composition.

7. The composition of claim 1 wherein the partially fluorinated ether of the solvent corresponds to the formula:

C p F 2p+1 —O—C q H 2q+1

wherein q is an integer from 1 to 5 and p is an integer from 5 to 11.

8. The composition according to claim 7 wherein the C p F 2p+1 — unit is branched.

9. The composition of claim 1 wherein the fluoropolymer comprises nitrile cure sites.

10. The composition of claim 1 wherein the fluoropolymer comprises one or more cure sites selected from iodine, bromine, chlorine, or a combination thereof.

11. The composition of claim 1 wherein the fluoropolymer comprises 40 to 60% by weight of polymerized units of TFE based on the total weight of the fluoropolymer.

12. The composition of claim 1 wherein the fluoropolymer contains 0 to 5 wt.- % of polymerized units derived from non-fluorinated or partially fluorinated monomers.

13. A composition comprising

at least one fluoropolymer, wherein the fluoropolymer comprises:

at least 90% by weight based on the total weight of the fluoropolymer of polymerized units derived from perfluorinated monomers selected from tetrafluoroethene (TFE) and one or more unsaturated perfluorinated alkyl ethers; and one or more cure sites selected from nitrile, iodine, bromine, or a combination thereof;

a fluorinated solvent; and

a curing agent comprising at least one amine group and at least one silane group.

14. The composition of claim 13 wherein the solvent has a GWP of less than 1000.

15. The composition of claim 14 wherein the fluorinated solvent is a branched, partially fluorinated ether and wherein the partially fluorinated ether corresponds to the formula:

R f —O—R

wherein R f is selected from perfluorinated and partially fluorinated alkyl or (poly)ether groups and R is selected from partially fluorinated and non-fluorinated alkyl groups.

16. The composition of claim 1 wherein the composition lacks a multi-olefinic crosslinker, free-radical photoinitiator, and combinations thereof.

17. A method of making the composition of claim 1 comprising dissolving the fluoropolymer in the solvent and adding the curing agent subsequently, concurrently, or after dissolving the fluoropolymer in the solvent.

18. A substrate comprising a coated surface wherein the coated surface comprises

a crosslinked fluoropolymer, wherein the fluoropolymer comprises at least 90% by weight based on the total weight of the fluoropolymer of polymerized units derived from perfluorinated monomers selected from tetrafluoroethene (TFE) and one or more unsaturated perfluorinated alkyl ethers; and one or more cure sites selected from nitrile, iodine, bromine, or a combination thereof; and

a curing agent comprising at least one amine group and at least one silane group.

19. A polymer sheet comprising a fluoropolymer wherein the fluoropolymer comprises at least 90% by weight based on the total weight of the fluoropolymer of polymerized units derived from perfluorinated monomers selected from tetrafluoroethene (TFE) and one or more unsaturated perfluorinated alkyl ethers; and one or more cure sites selected from nitrile, iodine, bromine, or a combination thereof; and

a curing agent comprising at least one amine group and at least one silane group.

20. A method of making a coated substrate comprising:

i) applying a coating composition to a substrate wherein the coating composition comprises

at least one fluoropolymer, wherein the fluoropolymer comprises cure sites and at least 90% by weight based on the total weight of the fluoropolymer of polymerized units derived from perfluorinated monomers selected from tetrafluoroethene (TFE) and one or more unsaturated perfluorinated alkyl ethers;

fluorinated solvent, and

an amine curing agent comprising at least one amine group and at least one silane group;

ii) removing the solvent; and

iii) curing the fluoropolymer at a temperature ranging from 135° C. to 170° C. or curing the fluoropolymer with ultraviolet radiation concurrently or prior to removing the solvent.