Conformal fluoropolymer coatings

Abstract

The present disclosure provides methods for forming a fluoropolymer coated component, such as a metal component, comprising applying an adhesion promoter onto a surface of the component; applying an organic material onto the adhesion promoter; and applying a mixture comprising a fluoropolymer and a solvent selected from a furan or a fluorinated solvent onto the organic material. Aspects of the present disclosure further provide fluoropolymer coatings having a thickness of from about 5 mil to about 80 mil on a component, an average porosity of from about 20% to about 70% based on the total volume of the layer, and a void density of from about 1011 to about 1013 voids per cm3.

What is claimed is: 
     
         1 . A method for forming a fluoropolymer coated component, comprising:
 applying an adhesion promoter onto a surface of a component;   applying an organic material onto the adhesion promoter; and   applying a mixture comprising a fluoropolymer and a solvent selected from a furan or a fluorinated solvent onto the organic material.   
     
     
         2 . The method of  claim 1 , wherein applying the adhesion promoter comprises applying the adhesion promoter onto a non-flat metal surface of the component. 
     
     
         3 . The method of  claim 2 , wherein applying the adhesion promoter comprises applying the adhesion promoter onto a metal surface comprising one or more of aluminum, nickel, steel, magnesium, or titanium alloy. 
     
     
         4 . The method of  claim 1 , wherein applying the adhesion promoter comprises applying an adhesion promoter that is the reaction product of acetic acid, zirconium tetra-n-propoxide, and (3-glycidyloxypropyl)trimethoxysilane. 
     
     
         5 . The method of  claim 4 , further comprising curing the adhesion promoter at a temperature of from about 30° C. to about 70° C. 
     
     
         6 . The method of  claim 1 , wherein applying an organic material onto the adhesion promoter comprises applying an organic material that is one or more of epoxy, a polyurethane, or a fiber-reinforced plastic. 
     
     
         7 . The method of  claim 6 , wherein applying an organic material onto the adhesion promoter comprises applying an organic material that is a layer having a thickness of from about 0.5 mil to about 5 mil and applying an adhesion promoter that is a layer having a thickness from about 0.5 mil to about 5 mil. 
     
     
         8 . The method of  claim 1 , wherein the fluoropolymer is selected from a fluoroacrylate, a fluorosilicone acrylate, a fluorourethane, a perfluoropolyether, a perfluoropolyoxetane, a polyvinylidenefluouride, and a perfluoroalkoxy alkane. 
     
     
         9 . The method of  claim 8 , wherein the solvent is a fluorinated solvent having a boiling point of from about 40° C. to about 200° C. 
     
     
         10 . The method of  claim 9 , wherein the fluorinated solvent is represented by formula (I):
   R 1 —(CF 2 ) n -R 2   (I)
   
       wherein n is an integer of from about 1 to about 25; R 1  and R 2  are independently —CF 3 , hydrogen, hydroxyl, hydroxyalkyl, aminoalkyl, aminoaryl, aryloxy, alkyl, aryl, carboxylic acid groups having from about 1 to about 25 carbons, aldehyde, ketone, and —CF 3 (CF 2 )q(CH 2 )p, wherein q is an integer from about 0 to about 25, and p is an integer from about 1 to about 25. 
     
     
         11 . The method of  claim 1 , wherein the solvent is a furan having a boiling point of from about 40° C. to about 200° C. 
     
     
         12 . The method of  claim 11 , wherein the furan solvent is represented by formula (IIa) or (IIb): 
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2 , R 3  and R 4  are independently hydrogen, hydroxyl, hydroxyalkyl, aminoalkyl, aminoaryl, aryloxy, alkyl, aryl, carboxylic acid groups having from about 1 to about 25 carbons, aldehyde, and ketone. 
     
     
         13 . The method of  claim 1 , wherein the mixture further comprises one or more additional polymers selected from epoxies, polyacrylates, polyesters, polyethers, carbamates, and polysiloxanes. 
     
     
         14 . The method of  claim 1 , wherein the mixture has a viscosity of from about 0.00046 Pa*s to about 1 Pa*s at 25° C. 
     
     
         15 . The method of  claim 1 , wherein applying the mixture comprises spraying the mixture onto the organic material layer at a pressure of from about 12 psi to about 18 psi. 
     
     
         16 . The method of  claim 15 , wherein applying the mixture comprises spraying multiple layers of the mixture to form a fluoropolymer layer having a thickness of from about 2 mil to about 20 mil on the organic material. 
     
     
         17 . The method of  claim 16 , wherein the fluoropolymer layer has an average porosity of from about 20% to about 70% based on the total volume of the layer. 
     
     
         18 . The method of  claim 16 , wherein the fluoropolymer layer has a void density of from about 10 11  to about 10 13  voids per cm 3 . 
     
     
         19 . The method of  claim 16 , wherein the fluoropolymer layer has an additive content of less than about 1 wt %. 
     
     
         20 . The method of  claim 16 , further comprising applying a second mixture comprising a fluoropolymer and a solvent selected from a furan or a fluorinated solvent onto the first fluoropolymer layer by spraying multiple layers of the second mixture to form a second fluoropolymer layer having a thickness of from about 2 mil to about 20 mil. 
     
     
         21 . The method of  claim 1 , further comprising heating the metal surface while applying the mixture onto the organic material to about 45° C. to about 55° C. 
     
     
         22 . The method of  claim 1 , further comprising forming a free standing film by applying a second mixture comprising a fluoropolymer and a solvent selected from a furan or a fluorinated solvent onto a mylar sheet. 
     
     
         23 . The method of  claim 22 , further comprising hot pressing the free standing film at a temperature of from about 90° C. to about 150° C. 
     
     
         24 . The method of  claim 23 , further comprising applying an epoxy adhesive to the free standing film or the fluoropolymer coated metal and pressing the free standing film to the fluoropolymer coated metal or the fluoropolymer coated metal to the free standing film to form a pressed assembly. 
     
     
         25 . The method of  claim 24 , further comprising disposing the pressed assembly onto a metal plate, disposing a bag over the pressed assembly, and applying vacuum to the vacuum bag at a pressure of from about 1 psi to about 20 psi. 
     
     
         26 . The method of  claim 25 , further comprising curing the pressed assembly at a temperature of from about 100° F. to about 300° F. at a temperature ramp rate of from about 1° F./minute to about 20° F./minute. 
     
     
         27 . An assembly comprising:
 a metal component; and   a fluoropolymer layer having a surface roughness of from about 5 microinches to about 100 microinches disposed on the metal component.   
     
     
         28 . The assembly of  claim 27 , wherein the fluoropolymer is selected from a fluoroacrylate, a fluorosilicone acrylate, a fluorourethane, a perfluoropolyether, a perfluoropolyoxetane, a polyvinylidenefluouride, and a perfluoroalkoxy alkane. 
     
     
         29 . The assembly of  claim 28 , wherein the fluoropolymer layer has an additive content of less than about 1 wt %.