Composite Medical Balloon With Adhesive-Free ePTFE–Thermoplastic Bonding
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Solution Overview
Problem
Existing medical balloons made of expanded polytetrafluoroethylene (ePTFE) face challenges in adhering to other materials due to low surface energy and high melt viscosity, leading to issues like trapped air and unpredictable deformation.
Innovation Solution
A composite medical balloon is formed through a stretch blow molding process that mechanically adheres a porous ePTFE layer to a thermoplastic layer without adhesives, creating a unitary structure with a patterned outer surface featuring recesses and protrusions to enhance adhesion and compliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ePTFE is adhered to other materials using conventional methods, then the balloon can be made with desired material properties, but adhesion is difficult due to low surface energy and high melt viscosity
Solution Approach 1:
The patent applies parameter changes by heating the ePTFE material to elevate temperatures during the molding process. This temporary parameter change reduces the material's viscosity and increases surface energy, enabling effective adhesion to other layers without requiring special adhesives or surface treatments. The thermal parameter modification allows conventional molding processes to successfully bond ePTFE to thermoplastic layers.
Solution Approach 2:
The patent creates a composite structure combining ePTFE with thermoplastic materials. This composite approach leverages the complementary properties of both materials: ePTFE provides low friction and chemical resistance, while the thermoplastic layer provides ease of processing and adhesion. The composite material strategy resolves the adhesion difficulty by pairing ePTFE with materials that have better bonding characteristics.
2Reliability
If ePTFE is used in medical balloons, then low coefficient of friction and chemical resistance are achieved, but trapped air and unpredictable deformation occur during processing
Solution Approach 1:
The patent uses parameter changes by controlling temperature and pressure during the molding process. Heating the ePTFE to elevated temperatures modifies its rheological properties, making it more compliant and easier to form into precise shapes. The controlled thermal parameter changes enable predictable deformation and eliminate trapped air by allowing the material to flow uniformly into the mold cavity.
Solution Approach 2:
The patent exploits phase transitions of the ePTFE material during processing. By heating the material to its melting or softening point, it transitions from a rigid, difficult-to-form state to a plastic, moldable state. This phase transition enables the material to be shaped precisely without trapping air, and then it solidifies upon cooling to maintain the desired form with predictable geometry.
3Device complexity
If a single layer material is used for the balloon, then the structure is simple, but it cannot optimize both adhesion and compliance simultaneously
Solution Approach 1:
The patent employs composite materials by combining ePTFE with thermoplastic layers to create a multi-layer balloon structure. Each layer contributes different properties: ePTFE provides low friction and chemical resistance, while the thermoplastic layer provides compliance and ease of processing. This composite structure simultaneously achieves adhesion and compliance optimization that would be impossible with a single material.
Solution Approach 2:
The patent applies segmentation by dividing the balloon wall into multiple functional layers. Rather than using a single homogeneous material, the balloon is segmented into distinct layers with specialized functions. This segmentation allows each layer to be optimized for its specific role while working together as an integrated structure, achieving both adhesion and compliance through functional division.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process results in a balloon with improved lubricious properties, reduced trapped air, and tailored compliance, achieving higher rated burst pressures and efficient therapeutic agent delivery.
Implementation Method 1
A composite medical balloon is formed through a stretch blow molding process that mechanically adheres a porous ePTFE layer to a thermoplastic layer without adhesives
Implementation Method 2
A composite medical balloon is formed through a stretch blow molding process
Implementation Method 3
A composite medical balloon is formed through a stretch blow molding process that mechanically adheres a porous ePTFE layer to a thermoplastic layer
Implementation Method 4
a polymeric layer having a porous microstructure wherein the porous polymeric layer is an outermost layer
Data Source
Figure 1a~1b
Figure 2
Figure 3a~3b
AI summary
The present disclosure is directed toward a composite balloon comprising a layer of material having a porous microstructure (e.g., ePTFE or expanded polyethylene) and a thermoplastic polymeric layer useful for medical applications. The layers of the composite balloons become adhered through a stretch blow-molding process. Methods of making and using such composite balloons are also described amongst others.