US Patent 11135808 PET release liner

A multilayer release liner for use in a roofing system, that includes a roofing membrane and an asphalt or bitumen adhesive. The multilayer release liner contains a core layer including PET, surrounded by several outer layers including at least two tie layers adhered to the core layer, and at least two polyolefin layers adhered to the tie layers. The multilayer release liner of the present invention is highly compatible with silicone and does not contain any ingredients that may interfere with the adhesion or cure of a silicone coating. The liner of the present invention also provides an effective oil barrier and minimizes oil migration and discoloration of the multilayer release liner from the adhesives used in roofing systems.