# US 2009/0260848 A1 · Microwires, methods for their production, and products made using them

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2009/0260848 A1
- Document ID: US20090260848A1
- Status: Published application
- Kind: A1
- Application number: 12/384,466
- Filed: 2009-04-06
- Published: 2009-10-22
- Earliest claimed: 2006-12-01
- Assignees: Pascale Industries, Inc.
- Inventors: Willorage Rathna Perera; Gerald J. Mauretti
- Web page: https://patentgrep.com/patent/US20090260848A1

## CPC

- D01D 5/34: Core-skin structure; Spinnerette packs therefor
- D01F 8/00: Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
- H01B 1/02: mainly consisting of metals or alloys
- H01B 3/423: {Linear aromatic polyesters}
- H01B 3/426: {Polycarbonates}
- Y10T 29/532: Conductor
- Y10T 428/2929: Bicomponent, conjugate, composite or collateral fibers or filaments [i.e., coextruded sheath-core or side-by-side type]
- D01D: MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## 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.

## Claims

### Claim 1

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.

### Claim 2 (depends on 1)

The method of claim 1, wherein said metal is selected from the group consisting of indium and its alloys, and tin and its alloys.

### Claim 3 (depends on 1)

The method of claim 1, wherein said polymer is selected from the group consisting of polycarbonates, polyethylene terephthalates, including glycol-stabilized polyethylene terephthalates, acrylics, nylon, and fluouropolymers.

### Claim 4 (depends on 1)

The method of claim 1, wherein at least one solid member of said metal is disposed in a bore in a solid member of said polymer prior to said melting step.

### Claim 5 (depends on 4)

The method of claim 4, wherein said at least one member of said metal comprises a plurality of wires of said metal disposed within said bore in said solid member of said polymer.

### Claim 6 (depends on 4)

The method of claim 4, comprising the steps of forming said bore by drilling into a solid member of said polymer without penetrating therethrough, so as to form a bore with one closed end, disposing said member of said metal therein, and capping the open end of the bore, and wherein said codrawing step is commenced by application of tension to the end of said solid member including said closed end of said bore.

### Claim 7 (depends on 6)

The method of claim 6, wherein said solid member of said polymer is weakened so as to control the point at which application of tension to said solid member causes elongation of said solid member to commence.

### Claim 8 (depends on 4)

The method of claim 4, wherein said metal and said polymer are separately heated.

### Claim 9 (depends on 1)

The method of claim 1, wherein said quantity of said metal is heated while disposed within a first elongated inner crucible, and said polymer is heated while disposed in a second elongated outer crucible concentric with said first inner crucible.

### Claim 10 (depends on 9)

The method of claim 9, wherein said first and second crucibles are oriented vertically, with exit orifices at their lower extremities, whereby a filament of metal drawn from the inner crucible is codrawn with a tubular sheath of polymer drawn from the outer crucible.

### Claim 11 (depends on 10)

The method of claim 10, wherein the relative axial positions of the exit orifices of said inner and outer crucibles are readily adjustable with respect to one another.

### Claim 12 (depends on 9)

The method of claim 9, wherein said inner and outer crucibles are made of material of good heat conductivity and higher melting point than either said metal or said polymer, and which does not react with either, such that independent control of the heating of said metal and said polymer can be accomplished by application of heat to the inner and outer crucibles, respectively.

### Claim 13 (depends on 12)

The method of claim 12, wherein at least the inner surface of said inner crucible is coated with a material chosen to improve the flowing characteristics of the metal.

### Claim 14 (depends on 13)

The method of claim 13, wherein said material is chosen from the group consisting of nickel and polytetraflouoroethylene.

### Claim 15 (depends on 14)

The method of claim 14, wherein the material of said inner crucible is stainless steel and a nickel coating is applied by electroless plating.

### Claim 16 (depends on 1)

The method of claim 1, wherein a surfactant is added to the metal.

### Claim 17 (depends on 9)

The method of claim 9, wherein either or both of said crucibles are sealed, and said method comprises the further step of applying compressed gas or vacuum thereto.

### Claim 18 (depends on 1)

The method of claim 1, wherein said microwire comprises plural metal filaments made simultaneously by codrawing together with the polymer material.

### Claim 19 (depends on 1)

The microwire made by the method of claim 1.

### Claim 20 (depends on 19)

Products made employing the yarn of claim 19.

### Claim 21 (depends on 1)

The method of claim 1, comprising the further step of processing one or a plurality of the microwires thus made to form a yarn.

### Claim 22 (depends on 21)

The method of claim 21, wherein said yarn additionally includes ends of other materials selected to provide desired characteristics to the yarn.

### Claim 23 (depends on 21)

The yarn made by the method of claim 21.

### Claim 24 (depends on 21)

Products made employing the yarn of claim 21.

### Claim 25 (depends on 1)

The method of claim 1 wherein the polymer material is chosen to exhibit desired engineering properties.

### Claim 26

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.

### Claim 27 (depends on 26)

The apparatus of claim 26, further comprising a takeup reel for winding a microwire comprising a metallic filament in a polymer resin sheath, such that said fiber is drawn down from an initial diameter to a final diameter, whereby the relative rate of takeup of said microwire with respect to the rate of discharge of said fiber determines the diameter of said microwire.

### Claim 28 (depends on 27)

The apparatus of claim 27, comprising a further heating device for applying further heat to the fiber after it has been drawn from the lower apertures of said inner and outer crucibles so as to enable the fiber to be drawn down further.

### Claim 29 (depends on 28)

The apparatus of claim 28, wherein the further heat is applied to the fiber and it is further drawn down after initial drawing and spooling steps have been performed.

### Claim 30 (depends on 26)

The apparatus of claim 26, wherein said intermediate portion of the outer surface of said tip comprises an elongated portion of generally constant diameter, and comprises smoothly-curved sections connecting the upper end of said elongated portion to the upper portion of the outside surface of said tip and the lower end of said elongated portion to said nipple, respectively.

### Claim 31 (depends on 30)

The apparatus of claim 30, wherein the inner surface of said inner crucible conforms generally to the outer surface thereof.

### Claim 32 (depends on 26)

The apparatus of claim 26, further comprising an automated device for inspecting the fiber as it is drawn.

### Claim 33 (depends on 32)

The apparatus of claim 32, further comprising an automated device, responsive to said automated device for inspecting the fiber as it is drawn, for controlling the level of metal in said inner crucible.

### Claim 34 (depends on 26)

The apparatus of claim 26, further comprising an automated device for monitoring and controlling the level of metal in said inner crucible.

### Claim 35 (depends on 26)

The apparatus of claim 26, further comprising a heater for maintaining the temperature of the metal in said inner crucible and of the resin in the outer crucible at predetermined levels.

### Claim 36 (depends on 26)

The apparatus of claim 26, wherein at least the inner surface of said inner crucible is coated with a material chosen to improve the flowing characteristics of the metal.

### Claim 37 (depends on 36)

The apparatus of claim 36, wherein said material is chosen from the group consisting of nickel and polytetraflouoroethylene.

### Claim 38 (depends on 36)

The apparatus of claim 36, wherein the material of said inner crucible is stainless steel and a nickel coating is applied by electroless plating.

### Claim 39 (depends on 26)

The apparatus of claim 26, further comprising apparatus for supply of a non-oxidizing gas to the inner crucible above the level of metal therein.