Recyclable Epoxy Adhesive With Cleavable Curing Linkages
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Solution Overview
Problem
Conventional epoxy adhesives are non-recyclable, posing a constraint in recycling and debonding adhesive joints, which is critical in demanding applications like wind turbine blades.
Innovation Solution
A recyclable epoxy adhesive system comprising 60-80% epoxy resin and 20-40% curing agent with cleavable linkages, allowing disintegration under heat and acid for recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional epoxy adhesives are used to achieve high mechanical strength and adhesion, then bonding performance is improved, but recyclability is lost
Solution Approach 1:
The patent changes the chemical parameters of the curing agent by incorporating cleavable linkages (acetal, ketal, orthoester, or carbamate groups) into the curing agent structure. These parameter changes allow the adhesive to maintain strong bonding performance while enabling controlled degradation under specific conditions (acidic environment or enzymatic treatment), thus achieving both high strength and recyclability
Solution Approach 2:
The patent creates a composite adhesive system by combining epoxy resin with specially designed curing agents that contain multiple functional groups including cleavable linkages. This composite approach integrates the strength-providing epoxy network with the degradation-enabled curing agent structure, resulting in an adhesive that simultaneously achieves high mechanical properties and recyclability through controlled breakdown
2Reliability
If epoxy adhesives are used for structural bonding to ensure reliability, then bond strength is improved, but debonding capability deteriorates
Solution Approach 1:
The patent modifies the chemical composition parameters of the curing agent to include cleavable linkages that remain stable under normal service conditions but become labile under specific degradation conditions. This parameter change enables the adhesive to provide reliable bonding during operation while allowing controlled debonding when exposed to acidic environments or enzymatic treatment, thus resolving the contradiction between bond reliability and debonding capability
3Strength
If traditional curing agents are used to achieve complete crosslinking, then mechanical strength is improved, but recyclability is worsened
Solution Approach 1:
The patent develops a composite curing agent system that integrates multiple functional components: hardening groups for crosslinking, and cleavable linkage groups for controlled degradation. This composite structure allows the adhesive to achieve complete crosslinking for high mechanical strength while maintaining inherent recyclability through the degradation-prone linkage groups that can be selectively activated under specific conditions
Solution Approach 2:
The patent changes the chemical structure parameters of the curing agent by incorporating cleavable linkages that can be selectively activated. These parameter changes enable the material to transition from a permanently crosslinked state to a degradable state, allowing complete material recovery and reuse, thus improving material recoverability while maintaining mechanical strength during service
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
Enables recycling of adhesive joints with high adhesion strength, low curing shrinkage, and resilience, suitable for structural bonding applications including wind turbine rotor blades.
Implementation Method 1
curing agent having at least one cleavable linkage... allowing disintegration under heat and acid for recovery
Data Source
AI summary
A recyclable epoxy adhesive system is disclosed. The recyclable epoxy adhesive system comprises 60-80% by wt. of an epoxy resin component having one or more di-functional epoxy resin; and 20-40% by wt. of a curing agent component having one or more curing agent having at least one cleavable linkage.