Endoscope Flexible Tube Coating for Chemical Resistance and Adhesion

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Solution Overview

Problem

Existing flexible tubes for endoscopes have defects in the resin layer after molding, insufficient chemical resistance, and low adhesiveness between the topcoat layer and the resin layer, which affect their handleability and durability.

Innovation Solution

A flexible tube for endoscopes with a resin layer composed of a polyester elastomer, a phosphorus-containing compound, a thioether compound, and a hindered amine compound, which enhances chemical resistance and adhesiveness, while minimizing defects in the resin layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a resin layer is formed on the flexible tube substrate, then the chemical resistance is improved, but defects appear in the resin layer after molding

Engineering Contradiction:
Improvechemical resistanceVSAvoiddefects in resin layer
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the chemical composition parameters of the resin layer by incorporating specific additives (hindered amine compound at 0.01-5 parts by mass, phosphorus-containing compound or thioether compound) into the polyester elastomer base material. This compositional parameter adjustment improves chemical resistance while the controlled additive amounts prevent defects during molding, resolving the contradiction between reliability and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the resin layer composition is optimized for chemical resistance, then the adhesiveness between topcoat layer and resin layer is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improveadhesiveness between layersVSAvoidresin composition complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by concentrating the adhesion-enhancing function in a specific interface region. The hindered amine compound and phosphorus-containing/thioether compounds are positioned in the resin layer to create a chemically active interface that bonds effectively with the topcoat layer. This localized functional distribution achieves high adhesiveness without requiring complex multi-layer structures throughout the entire resin layer, thus balancing reliability with manageable complexity.

Inventive Principle:
Principle #3Local quality

3Duration of action of stationary object

If multiple resin components are used to improve chemical resistance, then the durability is enhanced, but the handling ease during manufacturing decreases

Engineering Contradiction:
ImprovedurabilityVSAvoidhandling ease
Core Design Contradiction:
Duration of action of stationary objectVSEase of operation

Solution Approach 1:

The patent creates a composite resin material system where polyester elastomer serves as the base material and hindered amine compounds along with phosphorus-containing or thioether compounds function as specialized additives. This composite structure combines the mechanical properties of polyester elastomer with the chemical resistance and adhesion properties of the additives, achieving enhanced durability while maintaining relatively simple handling procedures through established composite material processing techniques.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3646900B1Endoscope flexible tube, endoscope-type medical device, resin composition for coating endoscope flexible tube substrate, and resin composition set for coating endoscope flexible tube substrate
Publication Date: 2025.05.21 FUJIFILM CORP
  • EP3646900B1 patent drawingFigure 1
  • EP3646900B1 patent drawingFigure 2
  • EP3646900B1 patent drawingFigure 3

AI summary

Provided is a flexible tube, for an endoscope, having a flexible tube substrate, for an endoscope, that is flexible and tubular and a resin layer covering the flexible tube substrate for an endoscope. The resin layer includes one or more layers, the layers including a layer A including a polyester elastomer (a) as a resin component, at least one of a phosphorus-containing compound (b1) or a thioether compound (b2), and a hindered amine compound (c). Also provided are an endoscopic medical device including the flexible tube for an endoscope and a resin composition and a set of resin compositions that are suitable for forming the resin layer of the flexible tube for an endoscope.