Multilayer Catheter Tube With Thin Polyimide Reinforcement

The patent applies composite materials by combining fluororesin (for chemical resistance and biocompatibility) with polyimide resin (for mechanical strength) in a multilayer structure. The polyimide resin layer provides reinforcement to the fluororesin layer, achieving high tensile strength while keeping the overall thickness small (polyimide layer ≤15 μm). This composite approach resolves the contradiction between strength and thickness by leveraging the complementary properties of different materials.

The patent applies local quality by creating a multilayer structure where each layer has a specific function: the fluororesin layer provides chemical resistance and biocompatibility, while the thin polyimide resin layer (≤15 μm) provides localized mechanical reinforcement. This localized reinforcement approach strengthens the tube where needed without increasing overall thickness, resolving the contradiction between tensile strength and tube thickness.

The patent uses composite materials to combine fluororesin (providing biocompatibility and chemical resistance) with polyimide resin (providing mechanical strength). The fluororesin layer maintains contact with bodily fluids for biocompatibility, while the polyimide resin layer reinforces the structure to provide adequate tensile strength, thus resolving the contradiction between biocompatibility and strength.

The patent applies local quality by assigning different functional properties to different layers: the fluororesin layer provides biocompatibility and chemical resistance where it contacts bodily fluids, while the polyimide resin layer provides mechanical strength reinforcement. This functional differentiation resolves the contradiction between biocompatibility and tensile strength.