Medical Guide Wire Multi-Layer Coating Adhesion

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Solution Overview

Problem

Existing guide wires with heat-shrinkable fluoroplastic resin coatings suffer from poor adhesion between layers, leading to torque transmission issues and peeling, and high material costs, as well as insufficient friction reduction.

Innovation Solution

A guide wire design featuring a core with a distal and proximal covering layer, where the underlying layer has a higher fluoroplastic resin content near the surface and the surface layer has a lower content, ensuring strong adhesion between layers and improved torque transmission, along with a flexible distal covering layer for reduced friction and enhanced safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a heat-shrinkable tube of fluoroplastic resin is used as the coating layer, then frictional resistance is reduced and slidability is improved, but adhesion between the core and the coating layer is poor and torque transmission is insufficient

Engineering Contradiction:
ImproveslidabilityVSAvoidadhesion
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The coating layer is divided into multiple distinct layers: a base layer (first coating layer) applied directly to the core, and an outer layer (second coating layer) applied over the base layer. This segmentation allows each layer to perform its specific function - the base layer provides strong adhesion to the core while the outer layer provides low friction and high slidability, thereby resolving the contradiction between adhesion and slidability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs composite material structure with different coating materials having complementary properties. The base layer uses materials optimized for adhesion to the core, while the outer layer uses fluoroplastic resin materials optimized for low friction. This composite approach allows the guide wire to simultaneously achieve both strong adhesion and high slidability, resolving the technical contradiction.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If a heat-shrinkable tube of fluoroplastic resin is used as the coating layer, then slidability is improved, but the material cost is high

Engineering Contradiction:
ImproveslidabilityVSAvoidmaterial cost
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The patent applies fluoroplastic resin material specifically in the outer layer where low friction and high slidability are most critical for catheter advancement. The base layer uses different materials optimized for adhesion, reducing the overall quantity of expensive fluoroplastic resin required while maintaining high slidability performance. This local application strategy reduces material cost while preserving the essential slidability benefit.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If the distal covering layer is made from a flexible material, then friction is reduced and safety is improved, but adhesion between the distal covering layer and the main body covering layer is poor causing peeling

Engineering Contradiction:
ImprovefrictionVSAvoidadhesion
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The coating structure is segmented into multiple layers with the distal covering layer (second coating layer) applied over the base layer (first coating layer). This segmentation enables the distal covering layer to be made from flexible material for reduced friction and improved safety, while the base layer provides strong adhesion to prevent peeling. The multi-layer structure resolves the contradiction between flexibility for friction reduction and adhesion for preventing peeling.

Inventive Principle:
Principle #1Segmentation

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 guide wire achieves reliable torque transmission, prevents peeling, and reduces friction, making it safer and easier to navigate through biological lumens with improved operational efficiency.

Implementation Method 1

a first coating layer that adheres to the surface of the core

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

the second coating layer... reduces frictional resistance and improves slidability

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2228094B1A guide wire
Publication Date: 2014.04.30 TERUMO KK
  • EP2228094B1 patent drawingFigure 1
  • EP2228094B1 patent drawingFigure 2
  • EP2228094B1 patent drawingFigure 3

AI summary

A guide wire (1) includes a core (3) possessing a distal end part (31) and a proximal end part (32), a distal covering layer covering the distal end part of the core, and a proximal covering layer (5) covering the proximal end part of the core. The proximal covering layer includes a first layer (6) that covers the surface of the core, and a second layer (7) that partly covers the surface of the first layer. The first layer has a first part (62) which is not covered by the second layer and a second part (61) which is covered by the second layer, and the surface of the second part is tightly surrounded by the proximal end of the distal covering layer (4).