Thermally Reworkable Adhesive for Electronic Devices
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Solution Overview
Problem
Thermoset adhesives, such as epoxies, once cured, are difficult to de-bond from electronic devices, leading to device disposal even when the adhesive outlasts the device, which hinders cost savings and recyclability.
Innovation Solution
A thermally reworkable adhesive composition comprising at least one di-epoxide, one diamine, and an additive that offsets the stoichiometry of the crosslinked polymer network by 5-50%, allowing the adhesive to be de-bonded from a device at a temperature range of 50-200°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermoset adhesives are used to achieve strong adhesion and longevity, then bonding strength is improved, but de-bonding becomes difficult and device recyclability deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the adhesive system by using a partially cured thermoset adhesive with unreacted functional groups. This allows the adhesive to maintain strong bonding strength while enabling de-bonding through chemical reaction with complementary molecules, thus resolving the contradiction between strong adhesion and ease of de-bonding
Solution Approach 2:
The patent introduces a de-bonding agent as an intermediary substance that reacts with unreacted groups in the adhesive. This mediator enables the de-bonding process without compromising the original bonding strength, allowing the adhesive to serve both functions of strong attachment and controlled removal
2Duration of action of stationary object
If thermoset adhesives are used to ensure adhesive outlasts the device, then durability is improved, but device disposal becomes necessary and cost savings deteriorate
Solution Approach 1:
The patent adjusts the curing parameters of the thermoset adhesive to achieve partial rather than complete cure. This parameter change allows the adhesive to maintain durability during device operation while retaining reactive groups that enable subsequent de-bonding for recycling purposes
Solution Approach 2:
The patent enables the recovery of valuable electronic components by allowing the adhesive to be removed through chemical de-bonding. This facilitates the discarding of only the adhesive material while recovering and reusing the expensive electronic components, thus improving overall recyclability
3Reliability
If thermoset adhesives are used to achieve gold standard adhesion, then bonding performance is improved, but adhesive intractability worsens and requires external stimulus for de-bonding
Solution Approach 1:
The patent changes the crosslinking density and cure state parameters of the thermoset adhesive to create a partially cured network. This maintains reliable bonding performance while introducing sufficient chain mobility to allow de-bonding with external thermal stimulus, improving adhesive workability
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 thermally reworkable adhesive can be effectively de-bonded from devices after curing, enabling the reuse or recycling of electronic components while maintaining strong adhesion and durability.
Implementation Method 1
reaction of the at least one di-epoxide and the at least one diamine produces a crosslinked polymer network
Implementation Method 2
heating the cured reworkable adhesive to a temperature in the range of 50-200° C.
Implementation Method 3
the offset crosslinked polymer network comprises a thermally reworkable adhesive that once cured, can be de-bonded from a device to which it is attached at a temperature range of 50-200° C.
Data Source
AI summary
A thermally reworkable adhesive includes at least one di-epoxide, at least one diamine that is reactive with the at least one di-epoxide, at least one additive that is miscible, but not reactive, with the at least one di-epoxide and/or the at least one diamine. Reaction of the at least one di-epoxide and the at least one diamine forms a crosslinked polymer network and the at least one additive offsets the stoichiometry of the crosslinked polymer network by 5-50%. The offset crosslinked polymer network forms the thermally reworkable adhesive that once cured, at a temperature in the range of 20-200° C., can be de-bonded from a device to which it is attached at a temperature in the range of 50-200° C.