Catheter Liner Flexibility via Composite PTFE Elastomer Layers

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Solution Overview

Problem

Existing PTFE catheter liners are too stiff for certain applications, such as neurovascular procedures, where flexibility and low friction are required for effective implant delivery and clot removal.

Innovation Solution

A catheter design featuring an inner layer of thermoplastic elastomeric material, such as polyolefin-based thermoplastic elastomer, combined with a tie layer of low durometer polymer, and optionally reinforced with materials like coil wires or braids, to enhance flexibility and low friction properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If PTFE catheter liners are used, then low friction properties are achieved, but flexibility deteriorates

Engineering Contradiction:

ImprovefrictionVSAvoidflexibility

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent employs a composite liner structure consisting of an inner PTFE layer for low friction and an outer thermoplastic elastomeric layer for flexibility. The PTFE layer (5-15 microns thick) provides the low friction surface, while the elastomeric layer (15-50 microns thick) provides the necessary flexibility and radial compliance, resolving the contradiction between low friction and flexibility.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The liner is segmented into distinct functional layers: an inner PTFE layer dedicated to low friction properties and an outer thermoplastic elastomeric layer dedicated to flexibility and compliance. This segmentation allows each layer to optimize its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If PTFE catheter liners are used, then low friction properties are achieved, but radial compliance deteriorates

Engineering Contradiction:

ImprovefrictionVSAvoidradial compliance

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The composite liner structure with inner PTFE and outer thermoplastic elastomeric layers provides both low friction and radial compliance. The elastomeric outer layer specifically addresses radial compliance needs while the PTFE inner layer maintains low friction, eliminating the trade-off between these properties.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Different regions of the liner have different properties: the inner surface maintains PTFE's low friction characteristic, while the outer region provides elastomeric compliance. This local differentiation of material properties allows simultaneous optimization of friction and compliance characteristics.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250170307A1Low friction and flexible catheter liner

Publication Date: 2025.05.29 TELEFLEX LIFE SCIENCES LLC

AI summary

A catheter and method for producing a catheter having an inner layer having a polyolefin- or polyethylene-based thermoplastic elastomeric material; an outer layer; and a tie layer disposed between the inner layer and the outer layer. The tie layer is a low durometer polymer. The thermoplastic elastomeric material includes at least one of a polyolefin-based thermoplastic elastomer, including, in one embodiment, a polyethylene-based thermoplastic elastomer. The tie layer includes a maleic anhydride grafted linear low-density polyethylene.