Polyamide Catheter Tube Composition for Slidability and Burst Strength
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Solution Overview
Problem
Existing catheters face challenges in maintaining desirable slidability and burst strength, especially when navigating complex lesion sites in medical treatments, necessitating a balance between flexibility and rigidity.
Innovation Solution
A catheter tube configuration with a first polyamide layer containing a pressure resistance enhancer, composed of amorphous carbon and titanium oxide, is used, enhancing both slidability and burst strength through improved adhesion and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a polyolefin material is used for the inner tube to ensure excellent slidability, then the guidewire operation is enabled, but the burst strength and flexibility are insufficient
Solution Approach 1:
The patent applies composite materials by combining polyamide resin with specific additives (carbon black, titanium oxide, zinc stearate) to create an inner tube that achieves both excellent slidability and high burst strength. The composite formulation allows the material to exhibit properties superior to pure polyolefin while maintaining the desired lubricating characteristics.
Solution Approach 2:
The patent changes the material parameters by specifying precise compositional ratios: carbon black (1-10 parts by weight), titanium oxide (1-10 parts by weight), and zinc stearate (0.1-5 parts by weight) per 100 parts of polyamide resin. These parameter adjustments optimize both slidability and burst strength simultaneously.
2Adaptability or versatility
If the catheter is reduced in size and diameter to navigate narrower lesion sites, then pliability is improved, but the burst strength and structural integrity are compromised
Solution Approach 1:
The use of polyamide resin as the base material provides inherently high strength-to-weight ratio, enabling the catheter to maintain structural integrity even at reduced dimensions. The composite formulation with reinforcing additives further enhances this property, allowing small-diameter catheters to withstand high pressures without bursting.
Solution Approach 2:
The patent applies different material compositions to different layers of the catheter structure. The inner tube uses the specific composite formulation for slidability, while outer layers can use different formulations optimized for flexibility and radial strength, allowing the catheter to be both pliable and strong simultaneously.
3Strength
If a polyamide material is used for the inner tube to improve flexibility and burst strength, then the structural integrity is enhanced, but the slidability and guidewire operation become difficult
Solution Approach 1:
The patent combines polyamide resin with lubricating additives, specifically zinc stearate (0.1-5 parts by weight per 100 parts resin), to reduce friction between the guidewire and inner tube. This composite approach maintains the high burst strength of polyamide while adding the necessary slidability characteristics.
Solution Approach 2:
Zinc stearate acts as an intermediary substance that reduces direct contact friction between the guidewire and the polyamide inner tube surface. This lubricating additive mediates the interaction, enabling smooth guidewire passage while the polyamide matrix maintains structural strength.
4Adaptability or versatility
If the catheter is made more flexible to navigate complex lesion sites, then trackability is improved, but the ability to maintain lumen and prevent kinking deteriorates
Solution Approach 1:
The patent applies different material properties to different catheter components and layers. The inner tube uses the polyamide composite for flexibility, while reinforcement elements or outer layers provide kinking resistance. This localized differentiation allows the catheter to be flexible where needed while maintaining structural stability elsewhere.
Solution Approach 2:
The composite material structure with polyamide resin and additives creates a material that inherently resists kinking while maintaining flexibility. The specific formulation and layering provide both the adaptability to navigate complex anatomy and the structural memory to prevent permanent deformation.
Data Source
Figure 1(A)~1(B)
Figure 2~3
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AI summary
A catheter having a catheter tube includes a first polyamide layer and a second polyamide layer disposed on an outer surface of the first polyamide layer. The first polyamide layer contains a pressure resistance enhancer in an amount more than 10 wt.% but equal to or less than 30 wt.% of total solids content of the first polyamide layer. According to the invention, there is provided a catheter that includes a catheter tube having an inner surface with desirable slidability and having an excellent burst strength.