Composite Adhesive Sheets for Positional Stability Across Dissimilar Moduli
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Solution Overview
Problem
Strain in the curable adhesive layer between adherends of different materials leads to positional shifting, affecting accurate strain measurement in strain sensors and causing potential short circuits and reliability issues in densely packed electronic components.
Innovation Solution
An adhesive sheet with a tensile elastic modulus of 3.5 GPa or more, breaking elongation of 60% or more, and tensile shearing adhesive strength of 10 MPa or more, composed of an epoxy resin, acryl resin, curing agent, and inorganic filler, particularly bisphenol A-type epoxy resin and three functional or more epoxy resin, with an inorganic filler content of 30.0 to 68.0 mass%, is used to adhere members with differing elastic moduli.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional adhesive agent is used to adhere members with different elastic moduli, then the adhesive strength is sufficient, but strain in the curable adhesive layer causes positional shifting of the adherends
Solution Approach 1:
The patent changes the mechanical parameters of the adhesive sheet by controlling its tensile elastic modulus to be 0.5 GPa or more (after curing) and breaking elongation to be 60% or more. This parameter optimization allows the adhesive to maintain sufficient strength while reducing strain-induced positional shifting when adhering members with different elastic moduli.
Solution Approach 2:
The adhesive sheet uses a composite material system comprising epoxy resin, acryl resin, curing agent, and inorganic filler. This composite formulation enables simultaneous achievement of high tensile elastic modulus and high breaking elongation, resolving the contradiction between strength and positional stability.
2Reliability
If the tensile elastic modulus of the adhesive sheet is increased to reduce strain, then positional shifting is inhibited, but the breaking elongation decreases
Solution Approach 1:
The composite material system of epoxy resin + acryl resin + inorganic filler enables the adhesive sheet to simultaneously achieve high tensile elastic modulus (0.5 GPa or more) and high breaking elongation (60% or more). The epoxy resin provides rigidity while the acryl resin and inorganic filler contribute to elongation and stress distribution.
Solution Approach 2:
The patent optimizes the parameter combination of tensile elastic modulus and breaking elongation to a specific range (modulus ≥0.5 GPa, elongation ≥60%). This parameter control allows the adhesive to balance rigidity for positional stability with flexibility for elongation capability.
3Manufacturing precision
If an adhesive agent with high rigidity is used to prevent strain deformation, then positional accuracy is maintained, but the adhesive becomes brittle and loses flexibility
Solution Approach 1:
The patent changes the mechanical parameters to achieve tensile elastic modulus of 0.5 GPa or more while maintaining breaking elongation of 60% or more. This creates an adhesive that is rigid enough for positional accuracy but flexible enough to adapt to strain without becoming brittle.
Solution Approach 2:
The composite formulation combines epoxy resin (for rigidity) with acryl resin and inorganic filler (for flexibility and elongation). This composite structure provides both the rigidity needed for manufacturing precision and the flexibility needed for adaptability to different 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 adhesive sheet inhibits positional shifting due to strain, ensuring accurate strain measurement and preventing short circuits by maintaining rigidity and adhesive strength, even under external forces and temperature changes.
Implementation Method 1
an adhesive sheet of which tensile elastic modulus after cured is 3.5 GPa or more, and a tensile shearing adhesive strength of the adhesive sheet after cured is 10 MPa or more
Implementation Method 2
a tensile elastic modulus of the adhesive sheet after cured is the tensile elastic modulus of the first member or more
Implementation Method 3
maintaining rigidity and adhesive strength, even under external forces and temperature changes
Implementation Method 4
a breaking elongation is 60% or more
Data Source
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AI summary
The present disclosure provides an adhesive sheet to be used for adhering a first member and a second member, a tensile elastic modulus of the first member is smaller than a tensile elastic modulus of the second member; a breaking elongation of the adhesive sheet is 60% or more; a tensile elastic modulus of the adhesive sheet after cured is the tensile elastic modulus of the first member or more; and a tensile shearing adhesive strength of the adhesive sheet after cured is 10 MPa or more.