Method for applying a polymer coating to a substrate

Abstract

Corrosion resistant non-polar polymer coatings and method for applying the coatings to substrates is described, wherein a source of non-polar polymer powder is deposited as a coating onto the surface of a substrate by high temperature thermal spray, wherein the non-polar character of the powder and any additives thereto is substantially preserved during the high temperature thermal spray by using a mixture of a non-oxidizing shielding gas or reducing gas, or combination of the two, at one or more locations along the thermal spray to displace or react with ambient oxygen.

I claim:  
     
       1. A method for applying a corrosion resistant non-polar polymer coating to a substrate comprising the steps of: 
       (a) providing a source of non-polar polymer powder,  
       (b) generating a high temperature thermal spray of said powder for spraying said powder onto a substrate;  
       (c) introducing into said thermal spray at least one gas for substantially displacing or reacting with oxygen in said thermal spray and substantially preserving the non-polar character of said powder during the step of spraying said powder onto a substrate; and  
       (d) applying said powder as a coating onto said substrate using said thermal spray.  
     
     
       2. The method of  claim 1  wherein said non-polar polymer powder comprises a thermoplastic type polymer selected from the group consisting of polyethylene, ultra-high molecular weight polyethylene, high density polyethylene, polypropylene, nylon, polytetrafluoroethylene, polystyrene, polyester, acrylic, polymethylmethacrylate, acrylonitrile butadiene styrene, polyvinyl-chloride, polybutylene, polycarbonate, polyaramid, polysulfone, polyimide, tar, wax, latex, polyurethane, polyvinylidene chloride, cellulose acetate, phenolics, nitrophenolics, polyetheretherketone, and phenol-formaldehyde, or a thermoset type polymer selected from the group consisting of polyester, epoxy, acrylic, vinyl ester, polyurethane, phenolic, styrene butadiene, silicone, polyimide, polyurea, polysulfone, and nitrophenolics. 
     
     
       3. The method of  claim 1  wherein the step of generating a high temperature thermal spray of said powder is performed using a thermal spray gun. 
     
     
       4. The method of  claim 3  wherein said powder is sprayed at a velocity of about 10 to 900 mph. 
     
     
       5. The method of  claim 4  wherein said powder is sprayed at a velocity of about 700 mph. 
     
     
       6. The method of  claim 1  wherein said polymer powder is in the size range of from about 1 to about 250 microns. 
     
     
       7. The method of  claim 1  wherein said at least one gas is selected from the group consisting of carbon dioxide, nitrogen, argon, helium, krypton, carbon monoxide, neon, hydrogen, methane, ethane, propane, butane, pentane, hexane, septane, octane, nonane, decane, alcohols, acetylene, propylene, ethylene, butylene, pentylene, hexylene, septylene, octylene and hydrogen sulfide. 
     
     
       8. The method of  claim 7  wherein the step of introducing at least one gas is performed using a gas mixture consisting essentially of 90% carbon dioxide and 10% hydrogen. 
     
     
       9. The method of  claim 1  further comprising the steps of providing said substrate, cleaning a surface of said substrate to which said polymer coating is to be applied, and roughening said surface to a roughness of about 0.002 inch average prior to the application of said polymer coating. 
     
     
       10. A method for applying a corrosion resistant non-polar polymer coating to a substrate comprising the steps of: 
       (a) providing a substrate for receiving a polymer coating;  
       (b) spraying onto said substrate a layer of metal fibers or particles;  
       (c) providing a source of non-polar polymer powder;  
       (d) generating a high temperature thermal spray of said powder for spraying said powder onto said substrate;  
       (e) introducing into said thermal spray at least one gas for substantially displacing or reacting with oxygen in said thermal spray and substantially preserving the non-polar character of said powder during the step of spraying said powder onto a substrate; and  
       (f) applying said powder as a coating onto said substrate using said thermal spray.  
     
     
       11. The method of  claim 10  wherein the step of spraying said substrate with a layer of metal fibers or particles is performed using a thermal spray process. 
     
     
       12. The method of  claim 10  wherein said non-polar polymer powder comprises a thermoplastic type polymer selected from the group consisting of polyethylene, ultra-high molecular weight polyethylene, high density polyethylene, polypropylene, nylon, polytetrafluoroethylene, polystyrene, polyester, acrylic, polymethylmethacrylate, acrylonitrile butadiene styrene, polyvinyl-chloride, polybutylene, polycarbonate, polyaramid, polysulfone, polyimide, tar, wax, latex, polyurethane, polyvinylidene chloride, cellulose acetate, phenolics, nitrophenolics, polyetheretherketone, and phenol-formaldehyde, or a thermoset type polymer selected from the group consisting of polyester, epoxy, acrylic, vinyl ester, polyurethane, phenolic, styrene butadiene, silicone, polyimide, polyurea, polysulfone, and nitrophenolics. 
     
     
       13. The method of  claim 10  wherein the step of generating a high temperature thermal spray of said powder is performed using a thermal spray gun. 
     
     
       14. The method of  claim 13  wherein said powder is sprayed at a velocity of about 10 to 900 mph. 
     
     
       15. The method of  claim 14  wherein said powder is sprayed at a velocity of about 700 mph. 
     
     
       16. The method of  claim 10  wherein said polymer powder is in the size range of from about 1 to about 250 microns. 
     
     
       17. The method of  claim 10  wherein said at least one gas is selected from the group consisting of carbon dioxide, nitrogen, argon, helium, krypton, carbon monoxide, neon, hydrogen, methane, ethane, propane, butane, pentane, hexane, septane, octane, nonane, decane, alcohols, acetylene, propylene, ethylene, butylene, pentylene, hexylene, septylene, octylene and hydrogen sulfide. 
     
     
       18. The method of  claim 17  wherein the step of introducing at least one gas is performed using a gas mixture consisting essentially of 90% carbon dioxide and 10% hydrogen.