Polymer-coated metal substrate

Abstract

A method of producing a polymer coated bullet jacket comprises applying a polymer to a substrate and drawing the substrate. The coating provides sufficient thickness, ductility and durability to replace the conventional copper/zinc jacketing layer, but also has an appropriate amount of flexibility and adhesion to the substrate to allow the substrate to be formed into the bullet jacket after the polymer coating is applied. A bullet jacket comprises a ferrous or aluminum substrate and a polymer layer bound to the substrate and is essentially devoid of a metal layer on the ferrous substrate. A bullet jacket may also comprise a metal substrate, and a polyethylene terephthalate layer bound to the substrate. A coated steel strip comprises a metal substrate and a polymer layer bound to the substrate, where the polymer layer has a Taber abrasion resistance less than 20 mg wear per 250 revolutions.

1 . A method of producing a polymer coated bullet jacket, the method comprising: 
 applying a polymer to a substrate; and    drawing the coated substrate to form a polymer coated bullet jacket.    
   
   
       2 . The method of  claim 1 , wherein the polymer is a fluoropolymer selected from the group consisting of polymers of perfluoropropyl vinyl ether, tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride and mixtures thereof.  
   
   
       3 . The method of  claim 1 , wherein the substrate is a copper alloy, aluminum, non-plated steel, or steel plated with a metal selected from the group consisting of copper, nickel, brass, bronze, nickel zinc alloy, zinc and combinations thereof.  
   
   
       4 . The method of  claim 2 , wherein the substrate is a copper alloy, aluminum, non-plated steel, or steel plated with a metal selected from the group consisting of copper, nickel, brass, bronze, nickel zinc alloy, zinc and combinations thereof.  
   
   
       5 . The method of  claim 3 , wherein the polymer is selected from the group consisting of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl-fluoride, ethylene-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene-copolymer, fluoroethylene-propylene copolymer, perfluoralkoxy polymer, polychloro-trifluoroethylene, polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), and mixtures thereof.  
   
   
       6 . The method of  claim 1 , wherein applying the polymer to the substrate comprises a method selected from the group consisting of coil-coating, reverse roll-coating, film lamination, and co-extrusion.  
   
   
       7 . The method of  claim 2 , wherein applying the polymer to the substrate comprises a method selected from the group consisting of coil-coating, reverse roll-coating, film lamination, and co-extrusion.  
   
   
       8 . The method of  claim 4 , wherein applying the polymer to the substrate comprises a method selected from the group consisting of coil-coating, reverse roll-coating, film lamination, and co-extrusion.  
   
   
       9 . The method of  claim 4 , wherein the substrate is non-plated steel or aluminum and wherein the polymer additionally comprises a coloring agent.  
   
   
       10 . The method of  claim 5 , wherein the substrate is non-plated steel or aluminum and wherein the polymer additionally comprises a coloring agent.  
   
   
       11 . The method of  claim 1 , wherein the polymer is a polyester.  
   
   
       12 . The method of  claim 1 , wherein the polymer is polyethylene terephthalate.  
   
   
       13 . The method of  claim 1 , wherein the polymer has a melting temperature greater than about 200° C.  
   
   
       14 . The method of  claim 9 , wherein the polymer is polyethylene terephthalate.  
   
   
       15 . The method of  claim 1 , wherein the polymer has a surface roughness less than 30 microinches Ra.  
   
   
       16 . The method of  claim 1 , wherein the steel possesses an equiaxed grain shape and a grain size smaller than ASTM 10.  
   
   
       17 . A bullet jacket made according to the method of  claim 1 .  
   
   
       18 . A bullet jacket comprising: 
 a ferrous or aluminum substrate, and    a polymer layer bound to the substrate,    wherein the bullet jacket is essentially devoid of an additional metal layer on the ferrous or aluminum substrate.    
   
   
       19 . The bullet jacket of  claim 18 , wherein the polymer is selected from the group consisting of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl-fluoride, ethylene chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene-copolymer, fluoroethylene-propylene copolymer, perfluoralkoxy polymer, polychloro-trifluoroethylene, polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), and mixtures thereof.  
   
   
       20 . The bullet jacket of  claim 18 , wherein the polymer is a polyester.  
   
   
       21 . The bullet jacket of  claim 18 , wherein the polymer is polyethylene terephthalate.  
   
   
       22 . The bullet jacket of  claim 18 , wherein the steel possesses an equiaxed grain shape and a grain size smaller than ASTM 10.  
   
   
       23 . The bullet jacket of  claim 18 , wherein the steel is selected from the group consisting of normalized steel and strand annealed steel.  
   
   
       24 . A bullet jacket comprising: 
 a metal substrate, and    a polyethylene terephthalate layer bound to the substrate.    
   
   
       25 . A coated steel strip comprising: 
 a metal substrate, and    a polymer layer bound to the substrate,    wherein the polymer layer has a Taber abrasion resistance less than 20 mg wear per 250 revolutions.    
   
   
       26 . The coated steel strip of  claim 21 , wherein the polymer has a melting point greater than about 200° C.