Non-stick finish
View Patent ↗A non-stick coating on a substrate is provided wherein the coating comprises an overcoat and a primer adhering the overcoat to the substrate, the overcoat comprising fluoropolymer and an effective amount of ceramic particles, preferably at least 3 wt % based on the combined weight of the fluoropolymer and the ceramic particles in the overcoat, said ceramic particles having an average particle size of at least about 10 micrometers to increase the abrasion resistance of said coating as determined by the dry SBAR method.
1. A substrate having non-stick coating thereon comprising an overcoat and a primer adhering said overcoat to said substrate, said overcoat comprising fluoropolymer and an effective amount of ceramic particles having an average particle size of at least about 10 micrometers to increase the abrasion resistance of said coating as determined by the dry SBAR method by at least 50%.
2. The substrate of claim 1 wherein said amount of said ceramic particles is at least about 3 wt % based on the combined weight of said ceramic particles and said fluoropolymer in said overcoat.
3. The substrate of claim 1 wherein said primer also contains ceramic particles having an average size of at least about 10 micrometers.
4. The substrate of claim 1 wherein said primer comprises fluorine-free adhesion promoter and optionally, fluoropolymer.
5. The substrate of claim 4 wherein said adhesion promoter is selected from the group consisting of polyamideimide, polyether sulfone, and polyphenylene sulfide.
6. The substrate of claim 1 wherein said primer is substantially free of fluoropolymer.
7. The substrate of claim 1 wherein said non-stick coating includes a topcoat which comprises fluoropolymer and is free of said ceramic particles.
8. The substrate of claim 7 wherein said overcoat has a thickness which is less than the major dimension of said ceramic particles.
9. The substrate of claim 3 wherein said non-stick coating includes a topcoat which comprises fluoropolymer and is free of said ceramic particles.
10. The substrate of claim 1 wherein additionally inorganic film hardener is present in at least one of said primer and said overcoat, said inorganic film hardener having an average particle size of less than about 5 micrometers.
11. The substrate of claim 1 wherein the thickness of said overcoat is about 0.5 to 1 mil (12.7 to 25.4 micrometers).
12. The substrate of claim 1 wherein said ceramic particles have an average particle size of about 14 to 36 micrometers.
13. The substrate of claim 1 wherein said overcoat contains adhesion promoter in an amount of up to about 10 wt % based on the weight of said fluoropolymer.
14. The substrate of claim 1 wherein said primer and overcoat are sequentially applied to said substrate and said fluoropolymer and said ceramic particles are present in said overcoat prior to its being sequentially applied to said substrate.
15. The substrate of claim 13 wherein said adhesion promoter is selected from the group consisting of polyamideimide, polyether sulfone, and polyphenylene sulfide.
16. The substrate of claim 1 wherein said overcoat is substantially free of adhesion promoter.
17. The substrate of claim 1 wherein said primer and overcoat are sequentially applied to said substrate from a liquid medium.
18. The substrate of claim 1 wherein said substrate is cookware, bakeware, rice cooker, and inserts therefor, water pot, iron sole plate, conveyor, chute, roll surface or cutting blade.
19. The substrate of claim 1 wherein said ceramic particles have a Knoop hardness of at least 1200.
20. The substrate of claim 13 wherein said primer is free of said ceramic particles.