Co-Extruded Adhesive Sheet Laminate for Strength and Releasability

The patent changes the physical parameters of the resins by selecting specific resin types (polyethylene for release layer, polypropylene for substrate layer) with compatible melting points and viscosity ranges that enable them to be co-stretched together. This resolves the contradiction by finding resin combinations whose physical properties align for simultaneous stretching while maintaining layer integrity.

The patent creates a composite laminated structure where multiple resin layers (release layer, adhesive layer, substrate layer) are combined in a specific configuration. Each layer uses resin selected for its compatibility with adjacent layers during co-stretching, achieving both high strength through stretching and proper layer compatibility through careful material selection.

The patent selects polyethylene as the release layer resin with specific viscosity and melting point parameters that match the polypropylene substrate layer. This parameter matching enables the release layer to be co-stretched with the substrate layer while maintaining its protective function on the adhesive surface.

The patent merges the release layer and substrate layer into a single co-extruded and co-stretched laminated structure. This integration allows both layers to be formed simultaneously with compatible physical properties, eliminating the need for separate lamination steps while maintaining adhesive surface protection.

The patent combines extrusion and stretching operations into an integrated co-extrusion co-stretching process. The laminated film is co-extruded in a tubular form and then co-stretched in the longitudinal direction to achieve high strength while maintaining process efficiency. This merged approach eliminates the need for separate lamination steps required by conventional stretching methods.

The patent performs co-extrusion of the laminated structure before stretching. By pre-forming the multi-layer structure through co-extrusion with controlled resin distribution, the subsequent stretching operation can uniformly increase strength across all layers without causing layer separation or film breakage.

The patent inverts the conventional layer arrangement by placing the release layer as the outermost layer instead of the adhesive layer. This inversion prevents the adhesive layer from being exposed to foreign matters during handling and winding, eliminating roll staining and die drool while maintaining high strength through the co-stretched laminated structure.

The patent introduces the release layer as an intermediary protective barrier between the adhesive layer and the external environment. This release layer prevents direct contact between the adhesive layer and foreign matters or rollers, eliminating staining and drool issues while allowing the adhesive layer to maintain its bonding function when needed.

The patent merges the release layer formation with the substrate layer formation into a single co-extrusion operation. Both layers are extruded simultaneously and then co-stretched together in an integrated process, eliminating the need for separate lamination steps and reducing manufacturing complexity while ensuring proper releasability through appropriate release layer resin selection.

The patent forms the release layer and substrate layer structure in advance during the co-extrusion process, before final stretching and finishing operations. This preliminary formation of the laminated structure with proper layer configuration streamlines subsequent processing and eliminates the need for additional lamination steps, reducing overall manufacturing complexity.