Thermally detachable multilayer compositions bonded with thermo-plastic primers
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Solution Overview
Problem
Existing methods for detaching thermoset adhesives, such as those used in electric vehicle batteries, often cause damage to components due to high surface area attachments and broad temperature ranges, and involve hazardous chemicals or inefficient detachment processes.
Innovation Solution
A multilayer composition comprising a thermoplastic primer layer and a thermoset adhesive layer that allows detachment by heating, maintaining bond strength at low temperatures and facilitating separation at elevated temperatures through the softening or melting of the primer layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermoset adhesives are used for bonding, then bonding strength and long term durability are improved, but detachment becomes difficult and may damage components
Solution Approach 1:
The adhesive system is segmented into two distinct layers: a thermoset adhesive layer providing permanent bonding, and a thermoplastic primer layer providing reversible bonding. This segmentation allows each layer to perform its specific function - the thermoset layer ensures strong, durable attachment while the thermoplastic layer enables controlled detachment through thermal softening.
Solution Approach 2:
The thermoplastic primer layer acts as an intermediary between the substrate and the thermoset adhesive layer. It mediates the bonding interaction by providing a interface that can be thermally activated for detachment, thereby enabling the permanent thermoset adhesive to be removed without damaging the substrate or the bonded component.
2Ease of operation
If physical removal methods are used to detach thermoset adhesive, then detachment is achieved, but component damage occurs
Solution Approach 1:
The mechanical detachment process (prying, cutting, or laser ablation) is replaced with a thermal process. By heating the thermoplastic primer layer above its glass transition temperature, the material softens and loses adhesion, allowing the bonded components to be separated without mechanical force that could cause damage.
3Ease of operation
If solvents or chemicals are used to remove thermoset adhesive, then detachment is achieved, but chemical hazards are generated
Solution Approach 1:
Chemical removal methods using solvents, alkalis, or acids are replaced with a purely thermal process. Heating the thermoplastic primer layer above its glass transition temperature causes the material to soften and detach, eliminating the need for hazardous chemicals while achieving the same detachment goal.
4Area of stationary object
If common detachment methods are used on high surface area attachments, then detachment is attempted, but effectiveness is reduced and component damage increases
Solution Approach 1:
The thermal detachment process uniformly softens the thermoplastic primer layer across the entire bonded surface area, allowing simultaneous release from all attachment points. This eliminates the localized mechanical stress and uneven force distribution that occur with prying or cutting methods on high surface area attachments.
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 multilayer composition maintains strong bonding at room temperature while enabling facile detachment at elevated temperatures without damaging components, using a thermoplastic primer layer with a glass transition temperature range of 50° C. to 130° C.
Implementation Method 1
a glass transition temperature in the range of 50° C. to 120° C.
Implementation Method 2
but soften and/or melt at temperatures near and above the glass transition temperature (Tg) or melt point temperature (Tm) of the thermoplastic primer layer
Implementation Method 3
Thermoplastic primer layers disclosed herein may remain solid and maintain thermoset adhesive performance throughout operating temperatures for most applications (e.g., up to 50° C.)
Data Source
AI summary
Multilayer compositions include a substrate having a surface energy of 35 dynes/cm or greater; one or more thermoplastic primer layers comprising 55 wt % to 100 wt % of a maleic anhydride grafted chlorinated polyolefin and a glass transition temperature in the range of 50° C. to 120° C.; and one or more thermoset adhesive layers.