EVOH Multilayer Film Balancing Gas Barrier and Flexibility

The patent applies composite materials by creating a multilayer film structure combining EVOH (for gas barrier) with thermoplastic resin layers (for bending resistance and flexibility). Specifically, Claim 1 defines a multilayer film with at least one EVOH layer (A) and at least one thermoplastic resin layer (B), where the composite structure integrates the strengths of different materials to simultaneously achieve gas barrier properties and bending resistance without pinhole formation during stirring operations.

The patent applies local quality by creating a multilayer structure where different layers have different mechanical properties. The EVOH layer (A) provides gas barrier properties, while the thermoplastic resin layer (B) provides flexibility and bending resistance. This local differentiation of material properties within the composite structure allows the container to be both flexible enough for handling and resistant enough to prevent pinhole formation during stirring operations.

The patent resolves this contradiction through composite materials where the thermoplastic resin layer (B) is specifically designed to provide both the required bending resistance and flexibility. The composite structure allows the container to maintain high bending resistance to prevent pinholes while retaining sufficient flexibility for easy handling, as each layer contributes its specific mechanical properties to the overall performance.