High Gas Barrier Materials with Multilayer Morphology for Packaging Applications

Multilayer films are widely used in packaging industry to fulfil different applications. It is well known that multilayer structure is essential for high gas barrier packaging using EVOH, because moisture has negative effects on EVOH’s barrier properties [1, 2]. In order to effectively use EVOH in barrier applications, usually a moisture barrier layer and a tie layer are required [3, 4]. In this study, specially prepared polymeric compounds based on EVOH and polyolefin with good dispersion, proper compatibility/incompatibility and viscosity match are prepared. These special materials all yield a morphology that is similar to multilayered structure after the resins are extruded into thin film. Different from some previous researches [5, 6, 7], our technique involves with a precompound process, which ensure the multilayer morphology to form after resins are extruded into thin films. With multilayer-like morphology inside, EVOH phase is extended and protected. Therefore, good gas barrier (both OTR and WVTR) properties agreeing with series model calculation are reported for all film samples. These materials with multilayer-like morphology have also shown decent adhesion with different PE reins, so 3layer instead of 5-layer films are successfully fabricated, which are applicable in barrier packaging applications in terms of barrier and optical properties. It is expected that these special materials with multilayer-like morphology inside can be used as monolayer films or a layer in multilayer structures to enhance the barrier performance as well as process flexibility of EVOH resins.