Curable 1K Structural Adhesive for Humidity-Stable Electrochemical Debonding
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Solution Overview
Problem
Existing electrochemically debondable adhesives are hygroscopic, leading to water accumulation and compromised long-term stability and performance under harsh conditions such as high temperature and high humidity.
Innovation Solution
A curable and electrochemically debondable one-component (1K) structural adhesive composition comprising (meth)acrylate monomers, electrolytes, co-polymerisable acids, initiators, core-shell tougheners, and tougheners, which form a stable adhesive polymer matrix that maintains adhesion and debondability under harsh conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional adhesives are used to provide strong bonding strength, then adhesion strength is improved, but debondability deteriorates
Solution Approach 1:
The adhesive composition is segmented into distinct functional components: (a) adhesive matrix formers providing bonding strength, (b) electrolytes enabling electrochemical debonding, and (c) hydrophobic agents preventing water accumulation. This segmentation allows each component to perform its specific function without compromising the others, achieving both strong adhesion and controlled debondability.
Solution Approach 2:
The adhesive composition utilizes parameter changes through electrochemical reactions. When voltage is applied, the electrolyte enables ion transport that alters the chemical state at the adhesive-substrate interface, transforming the strong adhesive bond into a debonded state. This parameter change (electrochemical potential) allows reversible control of bond strength.
2Ease of operation
If electrolytes are added to enable electrochemical debonding, then debondability is improved, but long-term stability deteriorates due to water accumulation
Solution Approach 1:
A hydrophobic agent is introduced as an intermediary substance that mediates between the electrolyte and the adhesive matrix. This hydrophobic agent prevents water from accumulating in the adhesive composition while allowing the electrolyte to maintain its ionic conductivity for electrochemical debonding. The hydrophobic agent acts as a barrier that excludes water molecules without interfering with the electrochemical reactions.
Solution Approach 2:
The adhesive composition is a composite material combining multiple phases: the adhesive matrix, electrolyte crystals, and hydrophobic agent. This composite structure allows the hydrophobic agent to occupy interstitial spaces and prevent water ingress while maintaining the functional properties of the electrolyte and adhesive matrix. The composite nature enables simultaneous achievement of electrochemical debonding and long-term stability.
3Ease of repair
If mechanical processes are used to remove adhesive, then debondability is improved, but substrate surface integrity deteriorates
Solution Approach 1:
The invention replaces mechanical removal processes with an electrochemical system. Instead of using sand blasting, wire brushing, or scraping to remove adhesive, an electric voltage is applied to initiate electrochemical reactions at the adhesive-substrate interface. This electrochemical debonding mechanism eliminates the need for mechanical contact with the substrate surface, preventing damage while achieving complete debonding.
4Ease of repair
If aggressive chemicals or high temperature are applied for disassembly, then debondability is improved, but substrate surface integrity deteriorates
Solution Approach 1:
The invention replaces chemical and thermal removal processes with an electrochemical system. Instead of using aggressive chemicals or high temperature to dissolve or soften adhesive for removal, an electric voltage is applied to drive electrochemical reactions that selectively disrupt the adhesive-substrate interface. This electrochemical approach provides controlled debonding without the harsh conditions that damage substrate surfaces.
Solution Approach 2:
The electrolyte acts as an intermediary that enables debonding through electrochemical reactions rather than direct chemical attack on the substrate. The electrolyte facilitates ion transport and electrochemical reactions at the adhesive interface, allowing debonding to occur through chemical means that are selective and controlled, unlike aggressive chemicals that indiscriminately attack both adhesive and substrate.
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 composition provides good initial bonding strength, effective debondability, and high aging stability, maintaining adhesive properties under high temperature and high humidity without compromising stability.
Implementation Method 1
the electrolyte provides sufficient ionic conductivity to support a faradaic reaction at a bond formed between the composition and an electrically conductive surface and thus allows the composition to debond from the surface
Implementation Method 2
a free radical initiator; and, an electrolyte
Data Source
AI summary
The present invention relates to a curable and electrochemically debondable one-component (1K) structural adhesive composition comprising a) a (meth)acrylate monomer selected from the group consisting of hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, isobornyl acrylate, isobornyl methacrylate, methyl methacrylate and mixtures thereof; b) an electrolyte selected from the group consisting of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, 1-pentyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, 1-hexyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-heptyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, 1-nonyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, 1-decyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-dodecyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-tetradecyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-hexadecyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-octadecyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl) amide, and mixtures thereof; c) a co-polymerisable acid; d) an initiator; e) a core shell toughener; and f) a toughener. The composition according to the present invention can withstand harsh conditions (high temperature and high humidity) while maintaining adhesive and debonding properties.