COAXIAL CABLE

Abstract

A coaxial cable (10) includes at least one conducting wire (110), at least one insulting layer (120) coating a respective conducting wire, at least one shielding layer (130) surrounding the at least one insulting layer, and a single sheath (140) wrapping the at least one shielding layer. The shielding layer includes a polymer material (134) and a plurality of carbon nanotubes (132) embedded in the polymer material. The coaxial cable is, advantageously, an electromagnetic interference (EMI) shield cable.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present coaxial cable can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, the emphasis instead being placed upon clearly illustrating the present coaxial cable.

FIG. 1 is a perspective view of a coaxial cable of the first embodiment;

FIG. 2 is a plane, cross sectional view along the II-II direction of the coaxial cable in FIG. 1;

FIG. 3 is a plane, cross sectional view of a coaxial cable of the second embodiment; and

FIG. 4 is a plane, cross sectional view of a coaxial cable of the third embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present coaxial cable is further described below with reference to the drawings.

The present coaxial cable includes at least one conducting wire, at least one insulating layer, each insulating layer respectively surrounding a corresponding conducting wire, at least one shielding layer encompassing the at least one insulating layer, and a sheath wrapping the above-mentioned three parts thereof. The coaxial cable is, usefully, an electromagnetic interference (EMI) shield cable.

Referring to FIG. 1, a coaxial cable 10, according to the first embodiment, is shown. The coaxial cable 10 includes a conducting wire 110, an insulating layer 120, a shielding layer 130 and a sheath 140. The axis of the conducting wire 110, the insulating layer 120, the shielding layer 130, and the sheath 140 is consistent (i.e., such elements are coaxial), and the arrangement thereof is, in turn, from center to outer.

The conducting wire 110 can be a single wire or a number of stranded wires. The conducting wire 110 is made of a conducting material, such as a metal, an alloy, a carbon nanotube bundle, or a carbon nanotube composite having electrical conduction. Advantageous metals for this purpose are aluminum (Al) or copper (Cu). A particularly useful alloy is a copper-zinc alloy or a copper-silver alloy, wherein a mass percent of copper in the copper-zinc alloy is about 70% and that in the copper-silver alloy is about 10-40%. The carbon nanotube composite advantageously includes the carbon nanotubes and one of the above-mentioned alloys. Preferably, the mass percent of the carbon nanotubes in the carbon nanotube composite is 0.2%-10%. The carbon nanotube bundle is, usefully, a sort of carbon nanotube chain connected by van der Waals attractive forces between ends of adjacent carbon nanotubes.

The insulating layer 120 coating/surrounding the conducting wire 110 is an electric insulator/dielectric, and can be, for example, polytetrafluoroethylene (PTFE) or a nano-sized clay/polymer composite. The clay of the composite is a hydrated alumino-silicate mineral in a nano-sized layer form. The mineral can, for example, be nano-sized kaolinite or nano-sized montmorillonite. The polymer of the clay/polymer composite is, usefully, chosen from the group consisting a material of silicone, polyamide, and polyolefin, such as polyethylene and polypropylene. In the preferred embodiment, the clay/polymer composite includes nano-sized montmorillonite and polyethylene. The clay/polymer composite has many good properties such as electrically insulating, fire resistant, low smoke potential, and halogen free. The clay/polymer is an environmentally friendly material and can be applied as an electrically insulating material to protect the conducting wire and keep/maintain a certain space between the conducting wire and the shielding layer.

Referring to FIG. 2, the shielding layer 130 coating/encompassing the insulting layer 120 is a carbon nanotube/polymer composite including a polymer material 134 and carbon nanotubes 132 embedded therein. The polymer material 134 is, beneficially, a material such as polyethylene terephthalate (PET), polycarbonate (PC), acrylonitrile-butadiene styrene terpolymer (ABS), or PC/ABS. The carbon nanotubes 132 can, e.g., be single-walled carbon nanotubes, multi-walled carbon nanotubes, a single-walled carbon nanotube bundle, a multi-walled carbon nanotubes bundle, or mixtures thereof. To be uniformly distributed in the carbon nanotube/polymer composite, a preferred length of the carbon nanotubes 132 is 0.1 microns (μm) to 10 milimiters (mm), a preferred diameter of the carbon nanotubes 132 is 0.5-40 nanometers (nm), and a mass percent of the carbon nanotubes 132 in the carbon nanotube/polymer composite is 0.2-10%.

A method for manufacturing carbon nanotube/polymer composite includes the steps, as follows: providing a prepolymer solution; uniformly dispersing the carbon nanotubes 132 into the prepolymer solution; coating the prepolymer solution with the carbon nanotubes 132 therein directly on the outside of insulting layer 120; and solidifying/curing the prepolymer solution to obtain the polymer material 134 and thereby yield the carbon nanotube/polymer composite. Alternatively, another method for manufacturing carbon nanotube/polymer composite includes the following steps: melting the polymer material 134; dispersing the carbon nanotubes 132 uniformly into the melted polymer material 134; coating the melted polymer material 134 with the carbon nanotubes 132 dispersed therein directly on the outside of insulting layer 120; and solidifying the melted polymer material 134 and thereby obtaining the carbon nanotube/polymer composite, in contact with the outside of insulting layer 120.

The material of the sheath 140 is, advantageously, the same as the material used for the insulating layer 120. This kind of material has many good properties, such as good mechanical behavior, electrically insulating, fire resistant, chemically durable, low smoke potential, and halogen free. Thus, the material is an environmentally friendly material and can be applied to protect the coaxial cable 10 from external injury, such as physical, chemical, and/or mechanical injury.

Referring to FIG. 3, a coaxial cable 20, according to the second embodiment, is shown. The coaxial cable 20 includes a number of conducting wires 210, a number of insulating layers 220 each, respectively, surrounding a corresponding one of the conducting wires 210, a single shielding layer 230 surrounding all the conducting wires 210 with the corresponding insulating layer 220 coated thereon, and a single sheath 240 wrapping the shielding layer 230. The materials of the conducting wires 210, the insulting layer 220, the shielding layer 230, and the sheath 240 are substantially similar to the materials of the corresponding parts in the first embodiment.

Referring to FIG. 4, a coaxial cable 30, according to the third embodiment, is shown. The coaxial cable 30 includes a number of conducting wires 310, a number of insulating layers 320 respectively coating a corresponding one of the conducting wires 310, a number of shielding layers 330 respectively applied to a corresponding one the insulating layers 320, and a single sheath 340 wrapping all the conducting wires 310, as separately coated, in turn, with a corresponding insulating layer 320 and a corresponding shielding layer 330. The materials of the conducting wires 310, the insulting layers 320, the shielding layers 330, and the sheath 340 are substantially similar to the materials of the corresponding parts in the first embodiment. The arrangement of the respective shielding layers 330 each surrounding a corresponding one of the conducting wires 310 can provide quite good shielding against noises (i.e., electrical interference) from outside and between the conducting wires 310, which ensures the stable characteristics of the coaxial cable 30. Finally, it is to be understood that the embodiments mentioned above are intended to illustrate rather than limit the invention. Variations may be made to the embodiments without departing from the spirit of the invention as claimed. The above-described embodiments illustrate the scope of the invention but do not restrict the scope of the invention

Claims

1. A coaxial cable comprising: at least one conducting wire;at least one insulting layer, each insulating layer being respectively coated on a corresponding conducting wire;at least one shielding layer surrounding the at least one insulting layer, each shielding layer comprising a polymer material and a plurality of carbon nanotubes embedded in the polymer material; anda sheath wrapping the at least one shielding layer.

2. The coaxial cable as claimed in claim 1, wherein the coaxial cable comprises a conducting wire, an insulating layer applied directly upon the conducting wire, a shielding layer coated upon the insulating layer, and a sheath wrapping the shielding layer.

3. The coaxial cable as claimed in claim 1, wherein the coaxial cable comprises a plurality of conducting wires, a plurality of insulating layers each respectively coated on a corresponding one of the conducting wires, a shielding layer surrounding all the coated conducting wires, and a sheath wrapping the shielding layer.

4. The coaxial cable as claimed in claim 1, wherein the coaxial cable comprises a plurality of conducting wires, a plurality of insulating layers respectively coated on a corresponding one of the conducting wires, a plurality of shielding layers respectively coated on a corresponding one of the insulating layers, and a sheath wrapping all the conducting wires coated, in turn, with the corresponding insulating layer and the corresponding shielding layer.

5. The coaxial cable as claimed in claim 1, wherein the polymer material is selected from a group consisting of polyethylene terephthalate (PET), polycarbonate (PC), acrylonitrile-butadiene styrene terpolymer (ABS), and PC/ABS.

6. The coaxial cable as claimed in claim 1, wherein a mass percent of the carbon nanotubes in the shielding layer is about 0.2-10%.

7. The coaxial cable as claimed in claim 1, wherein an average length of the carbon nanotubes is about 0.1 microns to 10 milimeters, and an average diameter of the carbon nanotubes is about 0.5-40 nanometers.

8. The coaxial cable as claimed in claim 1, wherein the carbon nanotubes are selected from a group consisting of single-walled carbon nanotubes, multi-walled carbon nanotubes, single-walled carbon nanotube bundle, multi-walled carbon nanotubes bundle, and mixtures thereof.

9. The coaxial cable as claimed in claim 1, wherein the conducting wire is made of a metal material or a carbon nanotube/polymer composite material.