Pipe preformed liner comprising metal powder
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 lined pipe comprising:
forming a preformed liner, wherein the preformed liner comprises a copolymer of tetrafluoroethylene and perfluoro(alkyl vinyl ether) and an effective amount of a metal powder to adhere the liner to the surface of the pipe, wherein said metal powder is selected from the group consisting of zinc, copper, and tin or combinations thereof;
applying said preformed liner on the surface of the pipe, wherein the surface of the pipe is free from primer layer and adhesive; and adhering said preformed liner to the surface of the pipe.
2. The process of claim 1 , further comprising: roughening the surface of the pipe prior to applying said preformed liner on the surface of the pipe.
3. The process of claim 1 , wherein forming said preformed liner comprises extruding a copolymer of tetrafluoroethylene and perfluoro(alkyl vinyl ether) to form the preformed liner.
4. The process of claim 1 , wherein forming said preformed liner comprises co-extruding an inner layer and an outer layer together to form the preformed liner.
5. The process of claim 4 , further comprising co-extruding at least one intermediate layer between the inner layer and the outer layer to form the preformed liner.
6. The process of claim 1 , wherein said preformed liner further comprises a plurality of barrier particles.
7. The process of claim 4 , wherein the outer layer is free of metal powder.
8. The process of claim 4 , wherein the outer layer consists essentially of tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer.
9. The process of claim 1 , further comprising heating the pipe and/or the preformed liner applied on the surface of the pipe to adhere the preformed liner to the surface of the pipe.
10. The process of claim 9 , further comprising rotating the pipe about an axis while heating the pipe to adhere the preformed liner to the surface of the pipe.
11. The process of claim 1 , wherein the metal powder comprises zinc.
12. The process of claim 1 , wherein the steps of applying and adhering said preformed liner on the surface of the pipe comprises inserting said preformed liner into the pipe and adhering said preformed liner to an interior surface of the pipe.
13. The process of claim 1 , wherein the preformed liner has an initial outer diameter that is larger than an inner diameter of the pipe prior to the preformed liner being applied on and adhered to an interior surface of the pipe.