Fluoropolymer composition for oil pipe

Abstract

The present invention relates to a composition of tetrafluoroethylene/perfluoro(ethyl vinyl ether) copolymer particles and metal powder which enables the composition to the used for rotolining an interior surface of a hollow article, wherein the resultant lining adheres to such surface. The invention further relates to oil pipe having its interior surface rotolined with fluoropolymer, the rotolining containing an effective amount of metal powder to cause the rotolining to adhere to said interior surface and a process for rotolinig the interior of the oil pipe.

1 . Oil pipe having its interior surface rotolined with fluoropolymer, said rotolining containing an effective amount of metal powder to cause said rotolining to adhere to said interior surface  
     
     
         2 . The oil pipe of  claim 1  as down-hole oil pipe having an inner diameter of at least 2 in (5 cm) and length of at least 10 ft (3 m).  
     
     
         3 . The oil pipe of  claim 2  wherein said length is at least 20 ft (6.1 m).  
     
     
         4 . The oil pipe of  claim 1  wherein said rotolining comprises a primer layer of said fluoropolymer containing said metal powder and an overcoat of said fluoropolymer.  
     
     
         5 . The oil pipe of  claim 1  wherein said rotolining has a thickness 30 mils (762 micrometers) to 250 mils (6350 micrometers).  
     
     
         6 . The oil pipe of  claim 4  wherein said primer layer has a thickness of at least 762 micrometers (30 mils) and said overcoat has a thickness of 30 mils (762 micrometers) to 220 mils (5588 micrometers). (30-220 mils)  
     
     
         7 . Process for rotolining the interior surface of an oil pipe having an inner diameter of no greater than 6 in (15.2 cm) and length of at least 10 ft (3 cm), comprising introducing particles of rotolining composition comprising fluoropolymer and metal powder into the interior of said pipe, heating said pipe to a temperature above the melting temperature of said fluoropolymer, rotating said pipe around its longitudinal axis during said heating and rocking said pipe from end-to-end thereof during said rotating so as to distribute said composition over the entire interior of said pipe, the combination of said heating and said distributing causing said particles to melt and coalesce to form a rotolining on said pipe over its entire interior.  
     
     
         8 . Process of  claim 7  wherein said rotolining is a primer.  
     
     
         9 . Process of  claim 8  comprising applying a rotolined overcoat on said primer rotolining, said rotolined overcoat comprising fluoropolymer but being free of said metal powder.