Fluoropolymer bonding compositions
Provided are fluoropolymer blends comprising a fluoropolymer having a major amount of fluorothermoplastic, a bubble suppressing metal compound, a base and a phase transfer catalyst. Also provided are layered articles comprising a first layer having the described fluoropolymer blend and methods for making the layered articles.
1. A fluoropolymer blend comprising a fluoropolymer having a major amount of fluorothermoplastic, a bubble suppressing metal compound, a base and a phase transfer catalyst, wherein the bubble suppressing metal compound is a metal powder having a particle size no greater than 10 μm.
2. The fluoropolymer blend of claim 1 wherein the fluorothermoplastic is a copolymer derived from copolymerizable units comprising a perfluorinated alkyl olefin of the formula CF 2 ═CFR wherein R is F or a linear, branched, or cyclic perfluorinated alkyl group of 1 to 10 carbon atoms; a perfluoro(alkyl vinyl) ether; a perfluoro(alkoxy vinyl) ether; or combinations thereof.
3. The fluoropolymer blend of claim 1 wherein the fluorothermoplastic is a homo- or copolymer derived from polymerizable units of a perfluorinated alkyl olefin of the formula CF 2 ═CFR wherein R is F or a linear, branched, or cyclic perfluorinated alkyl group of 1 to 10 carbon atoms.
4. The fluoropolymer blend of claim 1 wherein the fluorothermoplastic is a copolymer derived from copolymerizable units selected from vinylidene fluoride, hexafluoropropylene, perfluorovinyl ethers, ethylene, propylene, chlorotrifluoroethylene, or combinations thereof.
5. The fluoropolymer blend of claim 1 wherein the fluorothermoplastic is a copolymer derived from copolymerizable units of tetrafluoroethylene and hexafluoropropylene; tetrafluoroethylene and perfluoro(propyl vinyl) ether; tetrafluoroethylene and perfluoro(methyl vinyl) ether; tetrafluoroethylene and perfluoro(ethyl vinyl) ether; tetrafluoroethylene and ethylene; tetrafluoroethylene and propylene; tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride; ethylene and chlorotrifluoroethylene; or combinations thereof.
6. The fluoropolymer blend of claim 1 wherein the fluorothermoplastic has 50 or more reactive endgroups per 10 6 carbon atoms.
7. The fluoropolymer blend of claim 1 wherein the fluorothermoplastic has fewer than 50 reactive endgroups per 10 6 carbon atoms.
8. The fluoropolymer blend of claim 1 wherein the bubble suppressing metal compound is Sn, SnO, Active Al, SnSO 4 , Fe, Zn, MgAl 2 (SO 4 ) 2 , Cr, or combinations thereof.
9. The fluoropolymer blend of claim 1 wherein the bubble suppressing metal compound is present in an amount less than 5% by weight based on the total weight of the fluoropolymer, metal compound, base, and phase transfer agent.
10. The fluoropolymer blend of claim 1 wherein the base is a Group 1 hydroxide, a Group 2 hydroxide, an alkoxide salt, or combinations thereof.
11. The fluoropolymer blend of claim 1 wherein the phase transfer catalyst is a salt of triphenylbenzylphosphonium, tetraphenylphosphonium, tributylalkylphosphonium, tetrabutylphosphonium, tributylbenzylammonium, tetrabutylammonium, triarylsulfonium, fluorinated analogues or combinations thereof.
12. The fluoropolymer blend of claim 1 having a bubble index that is 50% lower than the bubble index of a comparative fluoropolymer blend, wherein the comparative fluoropolymer blend is identical to the fluoropolymer blend of claim 1 except that it is substantially free of bubble suppressing metal compound.