Diels-Alder Polyol Enables Thermal Debonding
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Solution Overview
Problem
Current polyurethane polymer adhesives are not easily detachable from substrates, limiting the recyclability of adhered substrates and the reuse of multi-layer materials and multi-material structures.
Innovation Solution
A Diels-Alder polyol (DA polyol) comprising a Diels-Alder unit capable of a DA/rDA reaction and a dimer fatty residue is used to create a polyurethane polymer with enhanced debonding properties, allowing for thermal triggered reversible bonding and debonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polyurethane polymer adhesives are used, then strong bonding strength is achieved, but the adhesive becomes difficult to detach from substrates
Solution Approach 1:
The patent applies the dynamics principle by incorporating a Diels-Alder unit into the polyol structure, which enables the adhesive to transition between bonded and debonded states. The DA unit allows the polymer network to dynamically reconfigure upon thermal stimulation, transforming the static strong bond into a reversible system that can be detached on demand while maintaining strong bonding during use.
Solution Approach 2:
The patent employs parameter changes by utilizing thermal stimulation to alter the bonding state of the adhesive. The Diels-Alder unit undergoes a reversible chemical reaction when exposed to heat, changing the molecular structure from a bonded state (at lower temperatures) to a debonded state (at elevated temperatures), thereby enabling controlled detachment without compromising initial bonding strength.
2Strength
If permanent adhesive bonding is used, then strong joint strength is achieved, but recyclability of substrates is limited
Solution Approach 1:
The patent implements the discarding and recovering principle by designing an adhesive system where the Diels-Alder unit can be reversibly deactivated through thermal stimulation. This allows the adhesive to be discarded from the substrate in a controlled manner during recycling processes, enabling recovery of both the substrate and the adhesive material for reuse, while maintaining strong joint strength during the product's service life.
3Strength
If multi-layer materials are bonded with permanent adhesives, then structural integrity is achieved, but reuse of individual layers is difficult
Solution Approach 1:
The patent applies the dynamics principle to multi-layer structures by incorporating the Diels-Alder unit into the adhesive layer. This enables the adhesive to dynamically respond to thermal stimulation, allowing individual layers to be separated from the multi-layer structure when needed for repair or reuse, while maintaining structural integrity during normal use through strong bonding.
4Strength
If coatings are applied to substrates for protection, then coating adhesion is achieved, but coating removal without substrate damage is difficult
Solution Approach 1:
The patent employs parameter changes by utilizing thermal stimulation to control coating removal. The Diels-Alder unit in the coating adhesive undergoes a reversible reaction when heated, causing the coating to debond from the substrate in a controlled manner that prevents mechanical damage to the substrate, while maintaining strong adhesion during normal service conditions.
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 DA polyol-based polyurethane polymer achieves improved recyclability and reuse of substrates and coatings by enabling thermal debonding without damaging the substrate, while also providing intrinsic self-healing properties.
Implementation Method 1
a Diels-Alder unit capable of a DA/rDA reaction
Implementation Method 2
capable of a DA/rDA reaction
Data Source
AI summary
The present invention relates to a Diels Alder polyol (DA polyol), a polymer composition comprising the DA polyol, and use of the polymer composition comprising the DA polyol as a coating, adhesive, sealant, elastomer or composite. More specifically, Diels Alder polyol comprising: a) a Diels-Alder unit, wherein the Diels-Alder unit is capable of a DA/rDA reaction, and, b) a dimer fatty residue, wherein the DA polyol necessarily contains at least two functional groups selected from hydroxyl groups, amino groups and/or carboxyl groups.