Pipe preformed liner comprising metal powder

Abstract

The present invention relates to a preformed liner of tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer adhered to the surface of a pipe, and in particular, an oil well pipe, without the need for either a primer layer or an adhesive. The liner comprises an effective amount of metal powder which provides adhesion between the liner and the surface of the pipe. The present invention also relates to a process for making such pipe, where in a preferred embodiment, the liner is co-extruded to form an inner layer and an outer layer. This co-extrusion embodiment is particularly useful in applications where high purity is necessary. In this case, the inner layer comprises an effective amount of metal powder and the outer layer is pure tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer.

1 . A process for forming a pipe having a preformed liner comprising a copolymer of tetrafluoroethylene and perfluoro (alkyl vinyl ether) and an effective amount of metal powder to adhere the liner to the interior surface of the pipe, comprising forming said preformed liner, inserting said liner into the pipe and adhering the liner to the interior surface of the pipe. 
     
     
         2 . The process of  claim 1 , wherein the preformed liner and the pipe are heated. 
     
     
         3 . The process of  claim 1 , wherein the step of forming a preformed liner comprises co-extruding an inner layer and an outer layer together to form the preformed liner. 
     
     
         4 . The process of  claim 1  or  3 , wherein the pipe and the preformed liner are rotated about a single axis to heat the pipe and the preformed liner.