a process for the production of a permanently bonded polyester - polyolefin film laminate is disclosed herein . the process involves exposing the surface of polyester or polyolefin film to contact with a flame so as to prime the surface thereof and thereafter coating the primed surface of the film with a layer of a molten polyolefin or polyester , respectively . flame priming of the polyester or polyolefin film results in a permanent surface modification of the film . thus , the time lapse between the priming of the polyester or polyolefin film and the subsequent coating with the molten polymer may be a matter of days , if desired . multi - layer laminates which comprise a substrate - polyester - polyolefin laminate , e . g ., paperboard - polyester - polyolefin laminates , can be provided by the process of the present invention by providing a previously formed laminate of a substrate and a polyester film and flame priming the polyester surface of the laminate . thereafter , a layer of a molten polyolefin is coated onto the primed polyester surface .