Direct bonding, adhesive-free Multilayer Thermoplastic Systems for Oil & Gas Pipelines, Risers and Umbilicals

Abstract

Abstract Since the 1970ies, Multilayer Thermoplastic Systems have been a success in many applications, from food packaging films to automotive fuel hoses and tanks. The great advantage of these systems is to combine the strengths of its single materials, from mechanical strength and chemical resistance, ductility and crack resistance to price. In those industries, Multilayer Technology is state of the art and you can hardly find single material solutions any more. Although these advantages perfectly match the requirements of oil and gas applications, tough conditions combined with long lifetime requirements and expensive qualification programs have limited the use of multilayer systems up to now. As conditions are getting even tougher, sometimes a single material solution cannot meet the requirements any more. On the other hand, Multilayer Technology has been developed further and can now meet all requirements of the oil and gas industry. The authors will introduce two different multilayer systems based on Fluoropolymer – Polyamide combinations. As all combinations provide bonding without having to use an adhesive layer, delamination because of adhesive layer errors are impossible. As delamination of the direct bond after rapid gas decompression has been defined as one of the key show stoppers for multilayer systems used in pipelines and risers, development work first has been focused on RGD performance. The testing setup including peel testing and results will be shown. After that, further testing on the systems has been performed, for example chemical resistance testing, permeation tests and bonding performance over time in accelerated aging conditions. Another important development step has been to make the materials extrudable in large diameters and compatible to each other in processing. Both systems offer significant advantages over existing single material solutions. In this paper, PVDF-PA12 for Flexible pipes and EFEP-PA12 for Umbilicals will be introduced in more detail.