Microwires, methods for their production, and products made using them
AssigneePascale Industries, Inc.
InventorsWillorage Rathna Perera, Gerald J. Mauretti
Life of this patent
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Abstract
Insulated electrically conductive continuous 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.
Claims39
A method for making an insulated microwire comprising a electrically conductive metallic core and an insulative polymer sheath, comprising the steps of:
- selecting a metal of suitably high electrical conductivity and of relatively low melting point;
- selecting a polymer of relatively high melting point;
- disposing a quantity of said metal within a quantity of said polymer disposed in tubular form around said quantity of said metal;
- heating said metal and said polymer such that said metal is substantially liquified while said polymer is softened;
- and
- codrawing said polymer and said metal simultaneously, forming a microwire wherein said polymer forms an elongated tube sheathing a continuous filament of said metal.
Apparatus for formation of an insulated microwire comprising a conductive metallic central filament within an insulative polymer resin sheath, comprising:
- generally tubular elongated inner and outer crucibles, for receiving said metal and resin respectively,
- devices for heating the metal and polymer resin in said crucibles to respective desired temperatures,
- said inner and outer crucibles being mounted vertically with said inner crucible being mounted within
- said outer crucible, said outer crucible having a resin inlet opening at its upper end and a cylindrical resin discharge passage at its lower end,
- wherein the lower end of the outer crucible defines a frustoconical inner surface, having the cylindrical resin discharge passage disposed at the lowest central portion thereof, said cylindrical resin discharge passage terminating at a resin discharge aperture,
- wherein said generally tubular elongate inner crucible comprises a upper body and a tip affixed to the lower end of the upper body, said upper body having a metal inlet opening at its upper end, wherein said tip defines an outer surface and an inner surface, the outer surface thereof comprising a upper portion of a first larger diameter conforming generally to the outer diameter of said upper body portion of said inner crucible, an intermediate portion, and a elongated lower nipple of a second smaller diameter having a metal discharge aperture therein,
- an adjustment device for controllably varying the relative axial positions of the inner and outer crucibles, and
- wherein the length of the elongated lower nipple is longer than the cylindrical resin discharge passage, so that the relative axial positions of said inner and outer crucibles can be adjusted, so as to define the relative location of the resin discharge aperture of the outer crucible with respect to the metal discharge aperture in the lower end of said nipple, without variation in the cross-sectional area of the resin flow passage formed therebetween, whereby
- a fiber comprising a central filament of said metal surrounded by a sheath of said resin can be drawn from the lower apertures of said inner and outer crucibles.
Dependencies are inferred from the claim text.