Thermosetting Composition for Precision Device Bonding
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Solution Overview
Problem
Thermosetting compositions containing epoxy resin and thiol compounds face challenges with poor storage stability and difficulty in temporary bonding, especially in applications requiring high alignment precision, such as precision devices.
Innovation Solution
A thermosetting composition comprising an epoxy resin, a thiol compound with multiple thiol groups, a radical polymerizable compound, a photo radical polymerization initiator, and a radical scavenger, which allows for temporary bonding through photocuring and subsequent thermal curing, improving storage stability and adhesion strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thermosetting composition containing epoxy resin and thiol compound is used, then low-temperature curing ability and flexibility are improved, but storage stability deteriorates
Solution Approach 1:
A radical scavenger (e.g., BHT) is introduced as an intermediary substance to suppress unwanted radical reactions during storage. The radical scavenger captures free radicals that would otherwise cause premature polymerization, thereby maintaining storage stability while preserving the low-temperature curing capability of the epoxy-thiol system.
Solution Approach 2:
The composition parameters are optimized by controlling the ratio of epoxy resin to thiol compound (1:0.5 to 1:2 by mass) and limiting the thiol compound content to 10-50 parts by mass per 100 parts epoxy resin. These parameter changes ensure sufficient reactivity for low-temperature curing while minimizing spontaneous reaction during storage.
2Strength
If thermosetting composition is used for bonding, then adhesion strength is improved, but ability to perform temporary bonding deteriorates
Solution Approach 1:
The curing process is segmented into two distinct stages: (1) photocuring stage using a photo radical polymerization initiator to achieve temporary bonding with alignment capability, and (2) thermal curing stage to achieve final strong bonding. This segmentation allows the composition to provide both temporary positioning and permanent adhesion.
Solution Approach 2:
Photocuring is performed as a preliminary action before thermal curing. The photocuring step creates an initial bond that holds parts in aligned positions, allowing for adjustment and positioning before the final thermal curing process provides permanent fixation with maximum adhesion strength.
3Strength
If high adhesion strength is achieved, then bonding reliability is improved, but resistance to high-temperature high-humidity environments deteriorates
Solution Approach 1:
The composition creates a composite cured product combining crosslinked epoxy-thiol networks with polymerized radical polymerizable compounds. This composite structure provides both high adhesion strength through the epoxy-thiol crosslinking and improved environmental resistance through the additional polymer network that resists moisture and heat degradation.
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 achieves good storage stability and sufficient adhesion strength, enabling reliable temporary bonding and final bonding of precision devices with improved alignment precision and resistance to high-temperature, high-humidity environments.
Implementation Method 1
a photo radical polymerization initiator (D)
Implementation Method 2
a radical scavenger (E)
Implementation Method 3
heating the thermosetting composition to form the cured product
Data Source
AI summary
A thermosetting composition according to the present disclosure contains: an epoxy resin (A); a thiol compound (B) having at least two thiol groups per molecule; a radical polymerizable compound (C); a photo radical polymerization initiator (D); and a radical scavenger (E).