Blended fluoropolymer compositions

Abstract

Blended fluoropolymer compositions are provided. In one embodiment, a liquid dispersion of a first fluoropolymer is blended with a liquid dispersion of a second fluoropolymer. The first fluoropolymer may be polytetrafluoroethylene (PTFE), such as a low molecular weight PTFE (LPTFE) that has been polymerized via a dispersion or emulsion polymerization process, and which has not been agglomerated, irradiated, or thermally degraded. The LPTFE may be in the form of an aqueous dispersion, having a mean particle size of less than 1.0 microns (□m), with the LPTFE having a first melt temperature (T m ) of 332° C. or less. The second fluoropolymer may be a melt processable fluoropolymer (MPF), such as methylfluoroalkoxy (MFA), fluorinated ethylene propylene (FEP), or perfluoroalkoxy (PFA), for example, in the form of an aqueous dispersion, and having a mean particle size of less than 1.0 microns (□m). Blending of the dispersions facilitates interaction of the LPTFE and MPF on a submicron level to facilitate intimate blending such that, when the blended fluoropolymer composition is dried, a crystal structure representing a true alloy of the fluoropolymers is formed, having melt characteristics that differ from those of the individual fluoropolymers. The blended fluoropolymer composition may be used to provide a coating having improved impermeability, stain resistance, abrasion resistance, smoothness, and higher contact angles.

1 - 28 . (canceled) 
     
     
         29 . A blended fluoropolymer composition, comprising:
 low molecular weight polytetrafluoroethylene (LPTFE) having a number average molecular weight (M n ) less than 500,000;   perfluoroalkoxy (PFA) having a melt flow rate (MFR) greater than 4 g/10 min as determined by ASTM D1238;   the LPTFE present in an amount of 15 wt. % to 50 wt. % and the perfluoroalkoxy present in an amount of 50 wt. % to 85 wt. %, based on the combined weight of the LPTFE and perfluoroalkoxy; and   the blend in solid form and having an alloy crystal structure with at least melt characteristic which differs from the individual melt characteristics of the LPTFE and perfluoroalkoxy.   
     
     
         30 . The blended fluoropolymer composition of  claim 29 , wherein the LPTFE has a number average molecular weight (M n ) less than 200,000. 
     
     
         31 . The blended fluoropolymer composition of  claim 29 , wherein the LPTFE has a number average molecular weight (M n ) less than 100,000. 
     
     
         32 . The blended fluoropolymer composition of  claim 29 , wherein the LPTFE has a number average molecular weight (M n ) less than 70,000. 
     
     
         33 . The blended fluoropolymer composition of  claim 29 , wherein the melt characteristic is a melt point as determined by differential scanning calorimetry (DSC). 
     
     
         34 . The blended fluoropolymer composition of  claim 29 , wherein the solid form blended composition exhibits a melt point differing from individual melt points of each of the LPTFE and PFA. 
     
     
         35 . The blended fluoropolymer composition of  claim 29 , wherein the LPTFE is present in an amount of 40 wt. % to 50 wt. % and the PFA is present in an amount of 50 wt. % to 60 wt. %, based on the combined weight of the LPTFE and PFA. 
     
     
         36 . The blended fluoropolymer composition of  claim 29 , wherein the PFA has a co-monomer content of one or more monomers other than tetrafluoroethylene of 3.0 wt. % or greater. 
     
     
         37 . The blended fluoropolymer composition of  claim 29 , wherein the PFA has a co-monomer content of one or more monomers other than tetrafluoroethylene of 4.0 wt. % or greater. 
     
     
         38 . The blended fluoropolymer composition of  claim 29 , wherein the PFA has a co-monomer content of one or more monomers other than tetrafluoroethylene of 5.0 wt. % or greater. 
     
     
         39 . The blended fluoropolymer composition of  claim 29 , wherein the PFA has a co-monomer content of one or more monomers other than tetrafluoroethylene of 6.0 wt. % or greater. 
     
     
         40 . The blended fluoropolymer composition of  claim 29 , wherein the LPTFE has a first melt temperature (T m ) of less than 330° C. as determined by differential scanning calorimetry (DSC). 
     
     
         41 . The blended fluoropolymer composition of  claim 29 , wherein the LPTFE has a first melt temperature (T m ) of less than 320° C. as determined by differential scanning calorimetry (DSC). 
     
     
         42 . The blended fluoropolymer composition of  claim 29 , wherein the LPTFE has a co-monomer content of one or more monomers other than tetrafluoroethylene of 1.0 wt. % or less. 
     
     
         43 . The blended fluoropolymer composition of  claim 42 , wherein the co-monomer is perfluoropropylvinylether (PPVE). 
     
     
         44 . The blended fluoropolymer composition of  claim 29 , wherein said LPTFE is obtained via emulsion polymerization and without being subjected to agglomeration, thermal degradation, or irradiation. 
     
     
         45 . The blended fluoropolymer composition of  claim 29 , in the form of tubing. 
     
     
         46 . The blended fluoropolymer composition of  claim 29 , in the form of a hose liner. 
     
     
         47 . The blended fluoropolymer composition of  claim 29 , in the form of solid pellets. 
     
     
         48 . A fluoropolymer powder, obtained from the blended fluoropolymer composition of  claim 29 .