Conductive PSA Composition for Low PIM and Stable Peel Adhesion
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Solution Overview
Problem
Conductive pressure sensitive adhesives (CPSAs) face challenges in achieving high electrical conductivity while maintaining strong adhesion to electrical components without causing corrosion, and they also generate undesired passive intermodulation (PIM) signals, especially under elevated temperatures and humidity.
Innovation Solution
The conductive adhesives comprise a pressure sensitive adhesive matrix made of non-linear block copolymers, hydrocarbon-based tackifying resin, and aromatic reinforcing resin, with dispersed electrically conductive particles, providing high peel adhesion, low DC resistance, and resistance to temperature and humidity, while minimizing PIM.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive particles are added to PSA matrix to achieve high electrical conductivity, then DC resistance decreases, but adhesion strength and resistance to corrosion may be compromised
Solution Approach 1:
The patent uses a composite material system combining a specifically formulated PSA matrix (with non-linear block copolymers, hydrocarbon-based tackifying resin, and aromatic reinforcing resin) with electrically conductive particles. This composite structure allows the conductive particles to provide electrical conductivity while the optimized PSA matrix maintains adhesion strength and corrosion resistance, resolving the contradiction between conductivity and mechanical bonding performance.
Solution Approach 2:
The patent optimizes multiple parameters of the PSA matrix including the use of non-linear block copolymers with specific molecular structures, hydrocarbon-based tackifying resins, and aromatic reinforcing resins. These parameter changes in the matrix formulation allow the adhesive to maintain strong bonding and corrosion resistance even in the presence of electrically conductive particles, thereby resolving the contradiction between electrical conductivity and adhesion strength.
2Strength
If conventional PSA materials are used to achieve strong adhesion, then Peel Adhesion is high, but they generate undesired PIM signals under elevated temperatures and humidity
Solution Approach 1:
The patent changes the chemical and physical parameters of the PSA matrix by incorporating non-linear block copolymers, hydrocarbon-based tackifying resins, and aromatic reinforcing resins. These parameter changes result in an adhesive that maintains strong Peel Adhesion while having low PIM generation, especially under elevated temperatures and humidity conditions, thus resolving the contradiction between adhesion strength and harmful PIM signal generation.
Solution Approach 2:
The patent develops a disposable adhesive layer that is formulated to achieve the required adhesion performance while minimizing harmful PIM signals. The specific composition with non-linear block copolymers and hydrocarbon-based tackifying resin creates an adhesive that performs its function effectively and then can be removed without causing corrosion or generating significant PIM, addressing the contradiction between strong adhesion and low harmful output.
3Reliability
If conductive particles are dispersed in PSA matrix to provide grounding performance, then electrical conductivity increases, but the adhesive may adversely affect electrical components
Solution Approach 1:
The patent employs a composite material system where electrically conductive particles are dispersed in a specifically formulated PSA matrix containing non-linear block copolymers, hydrocarbon-based tackifying resin, and aromatic reinforcing resin. This composite structure provides the necessary electrical conductivity for grounding performance while the optimized PSA matrix acts as a protective barrier that prevents corrosion of electrical components, resolving the contradiction between grounding performance and component protection.
Solution Approach 2:
The PSA matrix acts as an intermediary layer between the conductive particles and the electrical components. The specific formulation with non-linear block copolymers and hydrocarbon-based tackifying resin creates a protective interface that maintains electrical conductivity for grounding while preventing direct harmful interactions between the conductive particles and electrical components, thus resolving the contradiction between grounding performance and corrosion resistance.
4Strength
If adhesive formulation is optimized for strong bonding, then Peel Adhesion is high, but adhesion performance degrades under elevated temperature and humidity aging
Solution Approach 1:
The patent optimizes the parameters of the PSA matrix by incorporating non-linear block copolymers with specific molecular structures, hydrocarbon-based tackifying resins, and aromatic reinforcing resins. These parameter changes result in an adhesive formulation that maintains high Peel Adhesion and stability under elevated temperature and humidity aging conditions, resolving the contradiction between initial adhesion strength and long-term adhesion stability.
Solution Approach 2:
The patent uses a composite material system combining non-linear block copolymers, hydrocarbon-based tackifying resin, and aromatic reinforcing resin in the PSA matrix. This composite formulation provides both strong initial Peel Adhesion and resistance to degradation under elevated temperature and humidity aging, resolving the contradiction between adhesion strength and environmental stability.
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 adhesives maintain excellent adhesive and conductive properties even after aging, with low PIM, ensuring reliable performance in electronic devices.
Implementation Method 1
The conductive adhesive comprises a pressure sensitive adhesive matrix and electrically conductive particles... has a DC Resistance of less than 0.4 ohms
Implementation Method 2
at least one hydrocarbon-based tackifying resin... high Peel Adhesion
Data Source
AI summary
Conductive adhesives include a pressure sensitive adhesive matrix and electrically conductive particles. The matrix includes at least one non-linear block copolymer with aromatic end blocks and aliphatic elastomeric blocks, at least one hydrocarbon-based tackifying resin, and at least one aromatic reinforcing resin. The conductive adhesive is a pressure sensitive adhesive and has a 180° peel adhesion of at least 15.0 newtons/decimeter at room temperature, and when disposed on a copper foil substrate has a DC resistance of less than 0.4 ohms as measured by ETM-7. Upon aging on a conductive fabric substrate for at least 1 week at 85° C. and 85% relative humidity, the 180° peel adhesion changes by 25% or less.