Conductive Metal Nodes in Weldable High-Viscosity Adhesives
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Solution Overview
Problem
Weldable sealant and adhesive formulations with higher green-state viscosities face challenges in squeeze-out and bridging between substrates during resistance welding due to non-conductive fillers and fibers, leading to increased electrical resistance and reduced weldability.
Innovation Solution
Incorporating discrete solid metallic portions, such as carbon steel spheres, with diameters between 0.01 mm and 2.5 mm, which create nodes for improved weldability and electrical conductivity, allowing for higher viscosity formulations that maintain strength and handling properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If higher green-state viscosity sealant/adhesive formulations are used, then mechanical properties post-cure and processing/handling/packaging requirements are improved, but the ability to squeeze-out sufficiently to allow metal substrates to engage conductive fillers is reduced
Solution Approach 1:
The invention changes the physical state and electrical properties of filler particles by using conductive metal particles instead of non-conductive fillers. This parameter change allows the material to maintain high viscosity for mechanical strength while the conductive particles can still bridge gaps and provide electrical pathways for welding, resolving the contradiction between viscosity and weldability.
Solution Approach 2:
The invention uses composite material structure by combining conductive metal particles (such as nickel, copper, or aluminum) within the polymer matrix. This composite approach allows simultaneous achievement of high viscosity for mechanical properties and electrical conductivity for weldability, as the metal particles provide both structural reinforcement and electrical pathways.
2Strength
If non-conductive fillers and fibers are used to provide strength and corrosion resistance, then mechanical properties are improved, but electrical conductivity and weldability are inhibited
Solution Approach 1:
The invention fundamentally changes the electrical parameter of the filler particles from non-conductive to conductive by using metal particles. This parameter change allows the filler to simultaneously provide mechanical strength through the metal's inherent properties and electrical conductivity for welding, eliminating the trade-off between strength and conductivity.
Solution Approach 2:
The invention employs composite materials by incorporating conductive metal particles into the polymer matrix. The metal particles serve dual functions: providing mechanical reinforcement similar to traditional fillers and establishing electrical pathways for welding, thus achieving both strength and conductivity simultaneously.
3Strength
If conductive fillers are encapsulated by non-conductive polymeric materials, then strength and corrosion resistance are provided, but the material cannot be conductive in its supplied form
Solution Approach 1:
The invention extracts the non-conductive polymeric encapsulation layer that was isolating the conductive fillers. By removing this encapsulation, the conductive metal particles are directly exposed and can make contact with substrates and each other, enabling electrical conductivity in the supplied form while maintaining the polymer matrix for structural support.
Solution Approach 2:
The invention changes the surface property parameter of the conductive particles from encapsulated/non-conductive to exposed/conductive. This parameter change allows the conductive particles to maintain their electrical conductivity in the supplied state, eliminating the need for squeeze-out to expose them during welding.
4Ease of manufacture
If nonconductive fibers are used for flow control and dimensional stability, then processing properties are improved, but the material cannot move away or squeeze-out adequately during applied pressure
Solution Approach 1:
The invention changes the material composition parameter by replacing non-conductive fibers with conductive metal particles. The metal particles have different rheological properties that allow them to flow and squeeze-out under pressure while still providing flow control and dimensional stability, thus resolving the contradiction between manufacturing properties and welding operation.
Data Source
AI summary
A weldable adhesive or sealant formulation comprising a plurality of discrete solid metallic portions within a material having a viscosity of greater than 10,000 Pa s in its green state and at room temperature.