Abstract: In an injection molded polypropylene field joint of an oil or gas pipeline, the three- dimensional geometry of the injection molded/cast coating can have an influence on the stress placed on the line coating during cooling. Specifically, it has been found that molding or casting a coating having circumferential grooves, or other groove geometry, proximal to the interface with the line coating, will reduce line coating failure proximal to the field joint, in particular line coating failure related to the initial spooling/reeling of the pipe.

Abstract: A method of providing a foamed insulation coating on at least a portion of a pipe, including extruding a melt stream over the pipe portion. The melt stream includes a matrix polymer and expandable fillers in an unexpanded state, the melt stream being maintained at a sufficiently high temperature to maintain the matrix polymer in extrudable form and at a sufficiently high pressure to maintain the expandable fillers in the unexpanded state. Once extruded, the expandable fillers are permitted to expand into an expanded state at a lower pressure.

Abstract: A method of providing a foamed insulation coating on at least a portion of a pipe, including extruding a melt stream over the pipe portion. The melt stream includes a matrix polymer and expandable fillers in an unexpanded state, the melt stream being maintained at a sufficiently high temperature to maintain the matrix polymer in extrudable form and at a sufficiently high pressure to maintain the expandable fillers in the unexpanded state. Once extruded, the expandable fillers are permitted to expand into an expanded state at a lower pressure.

Abstract: A method of providing a foamed insulation coating on at least a portion of a pipe, including extruding a melt stream over the pipe portion. The melt stream includes a matrix polymer and expandable fillers in an unexpanded state, the melt stream being maintained at a sufficiently high temperature to maintain the matrix polymer in extrudable form and at a sufficiently high pressure to maintain the expandable fillers in the unexpanded state. Once extruded, the expandable fillers are permitted to expand into an expanded state at a lower pressure.

Abstract: A polymeric composition for insulating fluid and/or gas transport conduits, such as off-shore oil and gas pipelines operating at temperatures of about 200° C. or higher in water depths above 1,000 metres. The outer surface of the conduit is provided with at least one layer of solid or foam insulation comprising a high temperature resistant polysulfone having sulfone, ether and isopropylidene bridging groups, and/or a polyphenylsulfone or a polyethersulfone.