Foaming Adhesive Sheet Heating Sequence for Bond Strength
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Solution Overview
Problem
Adhesive compositions containing foaming agents face issues with decreased adhesive strength, leading to inferior reliability and durability of adhered members, despite satisfying the predetermined relationship between foaming start temperature and curing start temperature.
Innovation Solution
A method involving a foaming adhesive sheet with a thermosetting resin and a thermally expandable microcapsule, where specific conditions are met to ensure the curing reaction of the resin occurs before the shrinkage of the microcapsule, enhancing adhesive strength by maintaining the adhesive layer thickness during foaming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the adhesive composition includes a foaming agent and is heated under conventional conditions (T1≤T2), then the foaming process occurs, but the adhesive strength decreases
Solution Approach 1:
The invention applies preliminary action by designing the heating conditions so that the curing reaction of the thermosetting resin starts and progresses before the foaming agent begins to decompose and foam. This sequence ensures that the adhesive layer achieves sufficient curing strength before the foaming process causes expansion and potential weakening, thereby maintaining high adhesive strength and reliability
2Volume of moving object
If the foaming agent is used to expand the adhesive layer, then the adhesive layer thickness increases, but the adhesive strength may decrease due to improper heating sequence
Solution Approach 1:
The invention ensures that the curing reaction of the thermosetting resin is initiated first through controlled heating conditions (T2<T1), allowing the adhesive layer to develop structural strength before the foaming agent decomposes and expands the layer. This preliminary curing action prevents strength loss during the subsequent foaming expansion process
Solution Approach 2:
The invention utilizes phase transitions by controlling the temperature sequence to first trigger the curing reaction (chemical phase change) of the thermosetting resin, and then trigger the decomposition and foaming (physical phase change) of the foaming agent. This sequential phase transition management ensures that the adhesive layer maintains integrity while achieving the desired thickness increase
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 method improves adhesive strength and reliability by ensuring the thermosetting resin cures before the microcapsule shrinks, resulting in increased adhesive layer thickness and enhanced durability of the bonded product.
Implementation Method 1
the foaming agent is a thermally expandable microcapsule
Implementation Method 2
curing the adhesive composition by heating
Data Source
AI summary
A method for producing a product, the method including: a placing step of placing an adhesive composition, including a thermosetting resin and a foaming agent, between a first member and a second member; and an adhering step of adhering the first member and the second member by foaming and curing the adhesive composition by heating, wherein the foaming agent is a thermally expandable microcapsule; the adhesive composition has predetermined properties; and the adhesive composition is heated under predetermined heating conditions in the adhering step.