Resin Composition Compatibilization for Recycled EVOH Laminates

The patent introduces a compatibilizer as an intermediary substance to mediate between the thermoplastic resin without polar group and EVOH. The compatibilizer has both polar and non-polar characteristics, allowing it to interact with both resin types and improve their compatibility during melting and reusing processes, thereby preventing die drool, fish eye, and appearance defects while maintaining waste reduction benefits

The patent changes the chemical parameters of the compatibilizer by selecting specific types with controlled saponification degrees and ethylene content. Instead of using highly saponified EVA that causes discoloration, the patent employs compatibilizers with optimized parameters that provide sufficient compatibility improvement while minimizing thermal degradation and discoloration during processing

The patent creates a composite compatibilizer system combining multiple substances with complementary functions. This includes saponified EVA with controlled parameters, thermoplastic resin with polar groups, and additional compatibility-enhancing additives. The composite approach allows each component to contribute differently to compatibilization, maintaining mechanical strength while minimizing discoloration through synergistic effects

The patent applies local quality by using thermoplastic resin with polar groups specifically in the compatibilizer layer or at the interface between EVOH and non-polar thermoplastic resin layers. This localized application of polar-containing resin provides compatibility improvement exactly where needed at the interface, while the bulk layers maintain their original mechanical properties, thereby improving overall mechanical strength more effectively than uniform blending