Epoxy Adhesive for Endoscope Durability

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Solution Overview

Problem

Epoxy-based adhesives used in endoscopes fail to simultaneously achieve high levels of wet durability and sterilization durability, which are essential for maintaining the secured state of endoscope members after repeated exposure to wet conditions and sterilization treatments.

Innovation Solution

An adhesive composition for endoscopes is developed, comprising an epoxy resin as the base material, a polyamine compound with an oxyalkylene structure as the curing agent, and a metal alkoxide compound, specifically a silicon alkoxide compound, to enhance durability and adhesiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If epoxy-based adhesives are used to bond endoscope constituent members, then high workability and initial adhesiveness are achieved, but wet durability and sterilization durability are insufficient after repeated exposure to wet conditions and sterilization treatments

Engineering Contradiction:
ImproveadhesivenessVSAvoiddurability after repeated disinfection or sterilization treatment
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent uses a composite adhesive system combining epoxy resin as the base material with polyamine compound as curing agent. This composite formulation creates a cured product that maintains both high initial adhesiveness and superior durability after repeated disinfection and sterilization treatments, resolving the contradiction between initial bonding strength and long-term reliability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters of the adhesive by specifying the use of polyamine compound (having an oxygen atom but no amide bond) as the curing agent instead of conventional amines. This parameter change in the curing mechanism produces a cured adhesive with enhanced resistance to wet conditions and sterilization processes while maintaining adequate adhesiveness.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the diameter of the insertion section is reduced to alleviate patient discomfort, then ease of insertion is improved, but the use of bulky members such as screws for joining members becomes difficult

Engineering Contradiction:
Improveease of insertionVSAvoidjoining of members
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent replaces mechanical fastening systems (screws, bolts) with a chemical bonding system using epoxy-based adhesive. This substitution allows for secure joining of endoscope constituent members in the reduced-diameter insertion section without requiring bulky mechanical fasteners, thereby maintaining ease of insertion while enabling effective member joining.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 adhesive maintains sufficient adhesiveness and exhibits high long-term wet durability and sterilization durability, reducing performance degradation of endoscopes after extended exposure to wet conditions or repeated sterilization treatments.

Implementation Method 1

an epoxy-based adhesive contains an epoxy resin as a base material in combination with a particular polyamine compound as a curing component

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

if an epoxy-based adhesive contains an epoxy resin as a base material in combination with a particular polyamine compound as a curing component and further contains a metal alkoxide compound, a secured state in which a member is joined with the adhesive can be sufficiently maintained

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Data Source

PatentEP3932971B1Adhesive for endoscope, cured product thereof, and endoscope and manufacturing method thereof
Publication Date: 2025.04.16 FUJIFILM CORP
  • EP3932971B1 patent drawingFigure 1
  • EP3932971B1 patent drawingFigure 2~3
  • EP3932971B1 patent drawingFigure 4

AI summary

Provided are an adhesive for an endoscope, a cured product thereof, an endoscope including a member secured with the cured product, and a method for manufacturing the endoscope. The adhesive includes the following (a) to (c): (a) an epoxy resin including at least one of a bisphenol A epoxy resin, a bisphenol F epoxy resin, or a phenol novolac epoxy resin; (b) a polyamine compound having an oxygen atom but no amide bond in a molecule thereof; and (c) a metal alkoxide compound.