Medical fabric
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Solution Overview
Problem
Current stent graft fabrics face challenges in achieving a balance between low water permeability, high tear force, and thin thickness, particularly in branched portions, leading to issues with endoleak and structural integrity during implantation in the human body.
Innovation Solution
A medical fabric with specific woven texture characteristics, including multifilament yarns with adjusted twist coefficients, weft yarn overlap, and warp/weft yarn fineness ratios, is developed to create a seamless tubular fabric with enhanced burst strength and reduced water permeability, suitable for branched stent grafts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the thickness of stent graft fabric is reduced to enable low-profile catheter insertion, then the fabric can be inserted through narrow arteries, but the water permeability increases leading to endoleak
Solution Approach 1:
The patent applies parameter changes by precisely controlling the twist coefficients of warp and weft yarns within specific ranges (50-2000 and 50-1000 respectively) and adjusting the twist coefficient ratio between 0.05-2.0. This optimization of physical parameters enables the fabric to achieve both thinness (10-90 μm) and low water permeability (300 cc/min/cm² or less) simultaneously, resolving the contradiction between insertability and reliability
2Ease of operation
If superfine fibers with small total fineness and single filament fineness are used to reduce fabric thickness, then the fabric profile is reduced for catheter insertion, but the tear force decreases making the fabric prone to tearing at suture sites
Solution Approach 1:
The patent employs composite materials by combining multifilament yarns with specific configurations - using yarns composed of multiple fine filaments (0.5-5 μm diameter) twisted together. This composite structure at the yarn level allows the fabric to maintain thinness while achieving high tear force through the collective strength of bundled filaments, resolving the contradiction between thickness reduction and strength maintenance
3Volume of moving object
If the fabric is made thinner to reduce the stent graft profile, then the catheter size can be reduced, but the burst strength decreases compromising structural integrity during implantation
Solution Approach 1:
The patent applies parameter changes by optimizing the twist coefficients and their ratios within specific ranges, which enhances the structural efficiency of the thin fabric. This allows the fabric to achieve thinness (10-90 μm) while maintaining adequate burst strength through the optimized yarn configuration and twist parameters, resolving the contradiction between profile size and structural integrity
Data Source
AI summary
Provided is a medical fabric that is thin, and has both high tear strength and low water permeability. The medical fabric is characterized in that multifilament yarns having a total fineness of 7-80 dtex are disposed in the warp and weft, the single yarn fineness of at least one of the multifilament yarns among the warp and weft is 0.5 dtex or less, the twist factor A of the weft is 50-2,000, the thickness is 10-90 μm, and the water permeability both before and after puncture by a needle is 300 cc/min/cm2 or less.