Epoxy Adhesive Curing Agent for High Humidity Bond Strength

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Solution Overview

Problem

Conventional epoxy resin adhesives fail to maintain sufficient bond strength under high humidity conditions, which is critical for ensuring product reliability in applications like automobiles and industrial machinery.

Innovation Solution

A curing agent comprising reactive terminated polydiene, reactive polyamine, and amidine, specifically designed to enhance adhesiveness and moisture resistance, is used in combination with an epoxy resin to form an adhesive that maintains bond strength even under high humidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional epoxy resin adhesive is used, then good initial bond strength is achieved, but bond strength cannot be maintained under high humidity conditions

Engineering Contradiction:
Improvebond strength under high humidityVSAvoidhumidity effect on bond strength
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical composition parameters of the curing agent by incorporating specific ratios of polyether polyamine (30-70 wt%), non-polyether polyamine (10-50 wt%), and amidine (1-20 wt%). This parameter change in the curing agent composition enables the adhesive to maintain bond strength under high humidity conditions while achieving good initial bonding performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite curing agent system by combining multiple types of amines (polyether polyamine, non-polyether polyamine) with amidine compounds. This composite approach synergistically improves both initial bond strength and moisture resistance, resolving the contradiction between initial performance and humidity resistance

Inventive Principle:
Principle #40Composite materials

2Strength

If amine-terminated rubber and polyether are used as curing agents, then mechanical strength and collision resistance are improved, but bond strength deteriorates under high temperature and high humidity

Engineering Contradiction:
Improvemechanical strength and collision resistanceVSAvoidbond strength under high temperature and high humidity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent optimizes the compositional parameters of the curing agent by specifying precise weight percentage ranges for each component. The inclusion of amidine in 1-20 wt% range and the balanced ratio between polyether and non-polyether polyamines create a formulation that maintains both mechanical strength and humidity resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces amidine compounds as an intermediary substance that mediates between the epoxy resin and the amine components. This intermediary role of amidine enhances the overall performance of the adhesive system, particularly improving resistance to high temperature and humidity while maintaining mechanical properties

Inventive Principle:
Principle #24Intermediary (Mediator)

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 achieves good bond strength and moisture resistance, ensuring durability and reliability of bonded products even after storage under high humidity.

Implementation Method 1

A curing agent (B) for an epoxy resin, comprising: a reactive terminated polydiene (B1); a reactive polyamine (B2); and an amidine (B3).

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

An adhesive, comprising: an epoxy resin (A); and a curing agent (B), wherein the curing agent (B) comprises a reactive terminated polydiene (B1), a reactive polyamine (B2), and an amidine (B3).

Methodology Applied
Scientific EffectPolymerization:

Data Source

PatentUS20250109324A1Curing agent for epoxy resin, and adhesive
Publication Date: 2025.04.03 SUNSTAR GIKEN KK

AI summary

Excellent adhesive strength can be maintained to improve product reliability, even after storage under high humidity, by a curing agent (B) for an epoxy resin, the curing agent (B) containing a reactive terminated polydiene (B1), a reactive polyamine (B2), and an amidine (B3).