Microencapsulated Epoxy Hardener Infrared Curing Stability

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Solution Overview

Problem

Conventional latent epoxy resin hardeners have limitations in rapid curing reactivity, storage stability, solvent resistance, adhesiveness, dispersibility, and fluidity, which are crucial for applications in electronics and materials requiring high connection reliability and low-temperature curing.

Innovation Solution

A microcapsulated epoxy resin hardener with a core formed from epoxy resin hardener particles and a shell containing specific binding groups that absorb infrared radiation, providing improved storage stability, solvent resistance, and rapid curing reactivity, achieved by controlling the particle diameter, water content, and molecular weight distribution of the amine adduct.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional latent hardeners (dicyandiamide, BF3-amine complex, amine salts) are used to achieve good storage stability, then storage stability is improved, but curability deteriorates requiring high temperature or long time for curing

Engineering Contradiction:

Improvestorage stabilityVSAvoidcurability

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The hardener is segmented into microcapsules with a core-shell structure, where the core contains the latent hardener and the shell provides protection and controlled release, enabling both storage stability and rapid curability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the physical and chemical parameters of the hardener system by microencapsulation, transforming the hardener from a bulk material into controlled-release microcapsules with specific size distribution (0.3-12 μm), enabling rapid curing at room temperature while maintaining storage stability

Inventive Principle:

Principle #35Parameter changes

2Productivity

If latent hardeners with high curability are used, then curability is improved, but storage stability deteriorates requiring storage at low temperature

Engineering Contradiction:

ImprovecurabilityVSAvoidstorage stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The shell acts as an intermediary between the latent hardener core and the external environment, controlling the release of the hardener to maintain storage stability while enabling rapid curability when needed

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If conventional latent hardeners are used in mixtures containing solvents and reactive diluents, then application flexibility is improved, but storage stability deteriorates to extremely low levels

Engineering Contradiction:

Improveapplication flexibilityVSAvoidstorage stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The shell acts as an intermediary protecting the latent hardener from degradation by solvents and reactive diluents, maintaining storage stability while allowing application flexibility

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The microcapsule shell provides a protective barrier that is flexible enough to allow application in various formulations including solvents and reactive diluents, while maintaining storage stability

Inventive Principle:

Principle #30Flexible shells and thin films

4Stability of the object's composition

If conventional latent hardeners are used to achieve good storage stability, then storage stability is improved, but curing speed deteriorates requiring long curing time

Engineering Contradiction:

Improvestorage stabilityVSAvoidcuring time

Core Design Contradiction:

Stability of the object's compositionVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The microcapsule structure enables periodic release of the latent hardener, providing an initial burst of curing activity for rapid curing while maintaining storage stability before application

Inventive Principle:

Principle #19Periodic action

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 microcapsulated epoxy resin hardener exhibits superior storage stability, solvent resistance, adhesiveness, and fluidity, enabling high connection reliability and adhesive strength even at low temperatures, suitable for various applications including electrically conductive materials and fuel cell sealing.

Implementation Method 1

a shell (S) which covers the core (C), by forming a core (C) using a starting material of particles of epoxy resin hardener (H) having a specific range of average particle diameter, and a shell (S) covering the core having a binding group which absorbs infrared radiation with a specific wave number

Methodology Applied

Scientific EffectInfrared radiation absorption: Absorption (EM radiation)

Data Source

PatentUS7854860B2High-stability microencapsulated hardened for epoxy resin and epoxy resin composition

Publication Date: 2010.12.21 ASAHI KASEI CHEM CORP

AI summary

A microencapsulated latent hardener for epoxy resins which comprises cores (C) and shells (S) with which the cores are covered, characterized in that the cores (C) are ones formed from, as a starking material, particles of an epoxy resin hardener (H) comprising an amine adduct (A) and a low-molecular amine compound (B) as major ingredients and that the shells (S) have on the surface thereof connecting groups (x), (y), and (z) which absorb infrared. Also provided is an epoxy resin composition containing the hardener.