Insulated Microwire Co-Processing for Textile Integration
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Solution Overview
Problem
Existing methods fail to produce electrically conductive fibers, or microwires, with diameters between 10-100 microns that are both flexible and durable enough for textile applications, while maintaining electrical performance comparable to copper and being cost-effective.
Innovation Solution
The production of microwires involves co-processing a lower-melting-point metallic core with a higher-melting-point polymeric sheath in a single operation, using methods like the 'preform' or 'double-crucible' techniques, where the metal is melted within a softened polymer sheath, allowing for simultaneous formation of a continuous, insulated filament.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional methods of making insulated wire are used (drawing metal first, then extruding polymer), then the metal conductor can be made to size, but the process requires multiple separate operations and cannot achieve the desired fine diameter (10-100 microns) with adequate flexibility and durability
Solution Approach 1:
The patent combines the metal drawing and polymer insulation operations into a single simultaneous process. The metal core and polymer sheath are co-drawn together through a die assembly in one continuous operation, eliminating the need for separate drawing and extrusion steps. This merging of operations achieves the desired fine diameter (10-100 microns) while maintaining flexibility and durability, and reduces process complexity.
Solution Approach 2:
The patent uses preliminary action by pre-forming a composite preform with the metal core embedded in the polymer matrix before the drawing operation. This preform structure allows both materials to be processed simultaneously at their respective optimal temperatures and draw ratios, enabling precise control of the final fiber diameter and composition in a single step.
2Reliability
If the metal core is melted within the polymer sheath during co-drawing, then a continuous insulated filament is formed, but the polymer must withstand high temperatures without degrading
Solution Approach 1:
The patent applies parameter changes by controlling the temperature profile during co-drawing to maintain the polymer below its degradation temperature while allowing the metal core to melt and form continuous structures. The polymer is heated to a temperature sufficient to soften it for drawing but kept below the threshold that would cause degradation, achieving both metal continuity and polymer integrity through precise temperature parameter control.
3Temperature
If indium alloys are used as the conductive core material, then the melting point is low enough for co-processing with polymer, but the electrical resistance must remain comparable to copper
Solution Approach 1:
The patent uses composite materials by combining indium alloy with silver particles or other conductive additives to create a core material that has both low melting point (for co-processing with polymer) and high electrical conductivity (comparable to copper). This composite core structure allows the material to satisfy both the temperature and conductivity requirements simultaneously.
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
This approach enables the creation of flexible, durable, and electrically conductive microwires with resistance comparable to copper, suitable for textile integration, while significantly reducing production costs by using indium alloys and polymers like Bayer Macrolon and PETG.
Implementation Method 1
the metal of the core is melted while being confined within the polymeric sheath
Implementation Method 2
capillary action within the sheath as the core and sheath materials are codrawn causes the metallic core to form an elongated continuous conductive member
Data Source
AI summary
Insulated electrically conductive fibers or microwires of sizes on the order of 1 mil (25 microns) diameter, so as to be suitable for processing into yarns or multi-microwire bundles, for example, for incorporation into conformable fabric products or for use as wearable electronic circuitry are made by coprocessing a core of a lower-melting-point metal within a sheath of a higher-melting-point polymer.