Multilayer Barrier Film of Biaxially Oriented PA6/EVOH by Double Bubble Tubular Film Process

Abstract In the market, a film adapted to environmental and barrier problems is desired. The previous report discussed easy tear and gas barrier PA6 film. This report discusses the multilayer PA6 film having high barrier EVOH layer. A biaxially oriented PA6 film produced by double bubble tubular film process has high strength, but does not have enough gas barrier property compared with K-coated PA6. In the following a multilayer film with gas barrier layer is studied. A high gas barrier layer of EVOH is added to the center layer in the outer layers of PA6 films. The gas barrier ability increases with increasing the content of EVOH and decreasing ethylene content of EVOH, but at the same time the mechanical properties and processability get worse. From this point of view, it is found that the optimum content of EVOH is between 20% and 43%. In a biaxially oriented multilayer film composed of PA6 layers and EVOH one keeps high strength and high gas barrier. The material and production technology of a PA6 film can solve environmental and barrier problems.