Polymer Composition for Multilayer Packaging Delamination

An intermediate tie-layer comprising a polycondensation product of a diol and a dicarboxylic acid is introduced between the PGA barrier layer and PET structural layers. This tie-layer acts as a chemical bridge that forms strong intermolecular bonds with both adjacent layers through complementary functional groups, preventing interlayer delamination while maintaining the high gas barrier properties of the PGA layer and the mechanical strength of the PET layers.

The tie-layer is designed with specific compositional parameters - comprising 30-70 wt% diol units and 30-70 wt% dicarboxylic acid units - that create a balance between adhesion and recyclability. The moderate polarity and specific functional group density provide sufficient chemical bonding to prevent delamination while maintaining compatibility with standard recycling processes for polyester materials, allowing the multilayer structure to be processed without specialized chemical separation.

The invention creates a composite multilayer structure where a thin PGA barrier layer (providing excellent gas barrier properties) is combined with PET structural layers (providing mechanical strength) and a specifically designed tie-layer (providing chemical bonding). This composite approach allows each layer to contribute its optimal properties - the thin PGA layer maintains recyclability while the tie-layer ensures strong adhesion, achieving both high gas barrier performance and recycling compatibility simultaneously.