Multilayer Tube Interface Structure for Adhesive-Free Layer Bonding

The patent uses a composite material structure where a polypropylene resin layer containing organic particles (such as calcium carbonate, titanium oxide, or silica) is laminated with a polyamide resin layer. The organic particles create convex protrusions at the interface that enhance mechanical interlocking and increase the contact area between layers, thereby improving interlayer adhesion while maintaining the cost benefits and functional properties of the multilayer structure.

The patent applies local quality by concentrating organic particles specifically at the interface region between the polypropylene and polyamide layers. This localized modification creates convex protrusions precisely where adhesion is needed, without altering the bulk properties of either resin layer. The particles are distributed in the polypropylene layer adjacent to the interface, providing enhanced bonding capability exactly where required.

The patent applies beforehand cushioning by pre-forming convex protrusions at the layer interface using organic particles before annealing occurs. These protrusions create a robust mechanical interlocking structure that anticipates and resists the adhesive degradation that would normally occur during heat treatment. The interlocked structure maintains adhesion even when the resin layers soften during annealing, allowing flexibility improvement without adhesion loss.

The organic particles embedded in the polypropylene layer create a composite interface structure that remains stable during annealing. The inorganic nature of particles like calcium carbonate, titanium oxide, or silica provides thermal stability, maintaining the mechanical interlocking mechanism even when the organic resin matrix softens, thus preserving adhesion during flexibility-enhancing heat treatment.

The patent applies self-service by enabling the polypropylene and polyamide layers to bond to each other through self-formed mechanical interlocking via convex protrusions created by organic particles. This eliminates the need for external adhesives or additional bonding processes. The organic particles naturally create the anchoring structure during layer formation, providing adhesion through the inherent structure rather than requiring separate bonding materials or steps.

The patent extracts the adhesive function from the system by removing the need for separate adhesive materials and bonding processes. Instead of adding an external adhesive layer, the adhesion function is achieved through the structural modification of the polypropylene layer itself, which forms convex protrusions that mechanically interlock with the polyamide layer, thereby eliminating additional operation costs.

The patent combines maleic anhydride-modified polypropylene with organic particles to create a composite interface structure. The maleic anhydride groups provide chemical affinity with the polyamide layer, while the organic particles create mechanical interlocking through convex protrusions. This dual mechanism ensures adhesion stability during annealing, as the mechanical interlocking structure remains intact even when thermal conditions affect the chemical bonding.

The patent applies local quality by concentrating organic particles at the interface region where adhesion is critical. This localized modification ensures that the convex protrusions form precisely where the polypropylene and polyamide layers meet, providing enhanced mechanical interlocking exactly where needed to maintain adhesion stability during annealing, without modifying the bulk properties of the resin layers.