CN209993362U - Low dielectric constant communication cable - Google Patents

Abstract

The utility model discloses a low dielectric constant communication cable, which comprises a cable core, wherein the cable core consists of four pairs of line groups, and each pair of line groups is formed by mutually twisting two insulating core lines; the cable core is coated with a cable core shielding layer, and each pair of line groups are coated with a pair of line shielding layers; the insulating core wire comprises a core wire conductor, and a silica gel inner layer, a foam layer, a silica gel outer layer and a core wire thin film layer are sequentially coated on the core wire conductor from inside to outside; a cable core thin film layer, a sheath layer, a flame-retardant coating and a water-blocking coating are sequentially coated on the cable core shielding layer from inside to outside; the thickness of the silica gel inner layer and the silica gel outer layer is 3-5 μm, and the thickness of the core wire film layer is 4-6 μm. The inner silica gel layer and the outer silica gel layer are formed by coating room-temperature silicone rubber. The core wire film layer and the cable core film layer are high-temperature polyester film layers. The communication cable has a lower dielectric constant insulating layer structure, and not only has excellent electrical property, but also has chemical resistance and water and high temperature resistance.

Description

Low dielectric constant communication cable

Technical Field

The utility model relates to a digital communication cable that is used for a great deal of communication occasions such as intelligent building, data center and data transmission speed is fast, the security is reliable.

Background

The high frequency and high rate performance of the digital communication cable is closely related to the performance indexes such as impedance, attenuation and crosstalk. In the impedance performance of a digital communication cable, the characteristic impedance is mainly affected by the dielectric constant, the insulated conductor, the outer diameter of the conductor and the number of twists per unit length, while the input impedance of the cable is largely related to the outer diameter of the conductor, the mutual position between paired groups and the spacing structure of the conductors of the cable. The dielectric constant of the insulating layer, the mutual spacing of the conductors, will cause variations in the input impedance, the capacitance between the conductors and the attenuation values from their ideal values, all of which will obviously cause fluctuations and degradation in the transmission performance of the cable. One of the more important parameters affecting the performance of digital communication cables, especially high frequency digital cables, is crosstalk, and the systematic coupling crosstalk caused by electromagnetic coupling is caused by the mutual interference caused by the physical distance between conductors and between line groups, which is largely determined by the mutual positions of conductor loops, such as the constancy of the line group spacing, the stable state of the line group position, and the like.

Most of the existing digital communication cables are formed by twisting eight insulating core wires into four pairs of wire sets in pairs, twisting the four pairs of wire sets into a cable, and finally extruding an outer sheath to form a finished cable. The insulating layer of the wire group insulating core wire adopts a skin/foam/skin three-layer insulating structure, a plurality of foam hole foam layers which are dense and are not communicated with each other are arranged between the solid inner skin layer and the solid outer skin layer, and the dielectric constant of the foam hole foam layers is greatly reduced compared with that of the solid skin insulating layer, so that the insulating layer structure enables the communication cable to have better technical performance of transmitting high-frequency digital signals. Theoretically, the insulating layer on the insulated core conductor completely adopts a foaming structure, the dielectric constant of the insulating layer is lower, and the improvement of the transmission performance of high-frequency digital signals is facilitated, but on one hand, the adhesion between the metal conductor and the insulating layer is weaker, the physical position of the conductor is easy to shift and move, on the other hand, the mechanical strength of the outer foaming insulating layer is weakened, and the twisting collapse is easy to occur during twisting, so that the relative position of the paired conductors is seriously influenced, the insulating performance of the core is also influenced, and most of the insulated core wires in the communication cable adopt a skin/foam/skin structure taking polyolefin as a material. Because of the restriction of polyolefin material and crowded package technology, solid endotheca layer and solid cortex all can not be crowded package and get too thin, and the thickness of solid endotheca layer and cortex all is above 10 mu m (micron), and wherein solid endotheca layer thickness will be above 30 mu m at least, and solid cortex then can reach such thickness of millimeter level, and this is crowded the thickness space that has taken up the foam layer in fact, has restricted the further reduction of insulating layer dielectric constant.

In the use process of the communication cable, the communication cable is inevitably influenced by chemical components existing in the external environment and plasticizers and solvents in a cable sheath, harmful chemical components are gradually or accidentally transferred to corrode an insulating core shielding layer under a high-temperature environment along with the continuous prolonging of the use time, particularly when the cable is in an environment polluted by complex chemical substances such as acid, alkali and the like, these harmful chemical components not only corrode the insulated core of the cable, but also attack and change the properties of the material of the insulated core and the dielectric constant of the insulator, therefore, the impedance performance of the communication cable is changed, the transmission performance of the digital communication cable is directly influenced, the long-term stable high-frequency and high-speed transmission of the digital signals of the communication cable is difficult to ensure, and even the safe and reliable transmission of the digital signals is seriously influenced.

Meanwhile, the metal conductor and the solid inner skin layer of the insulating core wire are made of different materials, the adhesive force of the solid inner skin layer on the metal conductor is insufficient, the three-layer insulating structure is easy to move on the conductor in series, the relative positions of the two metal conductors in the wire set are displaced or changed, and then the structural parameters of the wire set are changed, so that the cable structure is unstable, and the working frequency of the high-frequency digital communication cable and the improvement of the data transmission speed are influenced.

The communication cable has wider and wider application range, not only can be laid in a high-temperature inflammable environment, but also can be laid in a humid environment, and in the high-temperature inflammable environment, a sheath layer of the communication cable is easy to melt and soften, so that the effect of protecting the cable by the sheath is lost; when the cable is in a humid working environment, moisture can invade the cable protective layer and even the core wire insulating layer, so that the aging speed of the insulating layer is accelerated, the service life of the cable is shortened, the dielectric constant of the insulating layer of the insulating core wire can be completely changed, and the electrical property of the communication cable is seriously deteriorated.

SUMMERY OF THE UTILITY MODEL

The above-mentioned not enough to prior art exists, the utility model aims to solve the technical problem that a low dielectric constant communication cable is provided, not only has lower insulating layer dielectric constant, can effectively block the erosion of harmful chemical composition to insulating heart yearn insulating layer moreover, and this cable still has good high temperature resistance that blocks water simultaneously.

In order to solve the technical problem, the low dielectric constant communication cable of the present invention comprises a cable core, wherein the cable core comprises four pairs of line groups, and each pair of line groups is formed by mutually twisting two insulation core lines; the cable core is coated with a cable core shielding layer, and each pair of line groups are coated with a pair of line shielding layers; the insulating core wire comprises a core wire conductor, and a silica gel inner layer, a foam layer, a silica gel outer layer and a core wire thin film layer are sequentially coated on the core wire conductor from inside to outside; a cable core thin film layer, a sheath layer, a flame-retardant coating and a water-blocking coating are sequentially coated on the cable core shielding layer from inside to outside; the thickness of the silica gel inner layer and the silica gel outer layer is 3-5 μm, and the thickness of the core wire thin film layer is 4-6 μm.

The utility model discloses low dielectric constant communication cable, because the cladding has the silica gel inlayer outside the heart yearn conductor, the foam blanket, silica gel skin and thin layer, thereby constituted the four-layer insulation system of heart yearn insulating layer, at first this structure becomes silica gel layer and thin layer through crowded covering solid polyolefin, makes the thickness of solid endothelial layer reduce 90%, the thickness of solid endothelial layer reduces 95%, thereby greatly increased the thickness of foam blanket, make the insulating layer dielectric constant and the work electric capacity of insulating heart yearn descend by a wide margin, thereby make the line transmission decay constant reduce, high frequency performance is good; in addition, the inner silica gel layer and the outer silica gel layer formed by coating silica gel on the two sides of the foam layer in the structure are respectively positioned on the inner side and the outer side of the foam layer, so that the foam layer forms a tight closed layer, the foam pore-forming degree and the pore size are always kept unchanged, the stability of the dielectric constant of the insulating layer is ensured, the extrusion resistance of the foam layer is greatly enhanced, the rigidity and the strength of bubbles in the foam layer are ensured, the stability of the distribution of the bubbles in the foam layer and the stability of the dielectric constant of the insulating layer are effectively ensured, and the adhesive force between the thin film layer and the foam layer is also ensured by arranging the outer silica gel layer between; the silica gel inner layer enables the insulating structure layer outside the conductor to be tightly and firmly adhered to the conductor, so that the relative and stable physical position of the conductor of the winding core wire is effectively ensured, and the relative position of the insulating core wire is ensured not to be displaced and changed even if the cable is laid, pulled or twisted; particularly, the core wire thin film layer is arranged on the outermost layer of the insulated core wire, and the core wire thin film layer is a high-temperature polyester thin film, so that the core wire thin film layer has excellent physical and chemical properties such as air tightness, moisture resistance and dimensional stability, and also has excellent mechanical properties such as obdurability, tensile strength and impact strength, and not only can effectively block the invasion and transfer of an outer sheath plasticizer and environmental harmful chemical substances to the core wire insulating layer, ensure the stability of the dielectric constant of the insulating layer, but also greatly enhance the mechanical strength of the surface of the insulated core wire. And because the cable core thin film layer is arranged between the cable shielding layer and the sheath layer, the tight sealing layer formed by the cable core thin film layer effectively prevents the plasticizer of the outer protective layer and volatile harmful chemical substances in the environment from invading the cable core, and forms double blocking protection with the core wire thin film layer, thereby preventing the volatile chemical substances from transferring and invading the insulating layer and ensuring the stability of the dielectric constant of the insulating layer. And the flame-retardant coating and the water-blocking coating are arranged on the sheath layer, so that the cable can be durable under high-temperature and severe working conditions, and the waterproof and flame-retardant protection capabilities of the communication cable are greatly improved. And because each paired line group is wrapped with the paired line shielding layer, the cable core is wrapped with the cable core shielding layer, and the paired line shielding layer and the cable core shielding layer form a double shielding structure, electromagnetic interference signals are effectively prevented from invading the paired insulated single lines, electromagnetic signal radiation inside the insulated single lines is prevented from leaking, and the double-shielded cable has a strict and reliable shielding effect.

The utility model discloses a preferred embodiment, silica gel inlayer and silica gel skin are formed by the coating of room temperature silicon rubber. Can exert good adhesive function at room temperature, and has good adhesive property and thin coating thickness.

The utility model discloses a preferred embodiment, heart yearn thin layer and cable core thin layer are high temperature polyester thin layer. Has excellent physical and chemical properties, and good air tightness and chemical resistance.

The utility model discloses a preferred embodiment, mould compound shielding area for copper to the line shielding layer. The cable core shielding layer is a foil tape shielding layer or a braided shielding layer. The sheath layer is a low-smoke halogen-free flame-retardant polyolefin extrusion coating layer.

Drawings

The low dielectric constant communication cable of the present invention will be described in further detail with reference to the accompanying drawings and embodiments.

FIG. 1 is a schematic cross-sectional view of an embodiment of the low dielectric constant communication cable of the present invention;

fig. 2 is a schematic sectional structure view of an insulated core wire in the embodiment shown in fig. 1.

In the figure, 1-core conductor, 2-silica gel inner layer, 3-foam layer, 4-silica gel outer layer, 5-core thin film layer, 6-paired wire shielding layer, 7-cable core shielding layer, 8-cable core thin film layer, 9-sheath layer, 10-flame retardant coating and 11-water blocking coating.

Detailed Description

The low dielectric constant communication cable shown in fig. 1 has a cable core formed by twisting four pairs of wire sets; each pair of line groups is formed by mutually twisting two insulated core wires, each pair of line groups is wrapped with a pair of line shielding layers 6, and the pair of line shielding layers 6 are copper-plastic composite shielding tapes or aluminum-plastic composite shielding tapes; the insulated core wire is composed of a core wire conductor 1 and a conductor insulating layer covering the conductor.

The cable core is coated with a cable core shielding layer 7, and the cable core shielding layer 7 is a copper foil shielding tape, or an aluminum foil shielding tape or a copper wire braided shielding layer. The cable core shielding layer 7 is wrapped with a cable core thin film layer 8, the cable core thin film layer 8 is also made of a high-temperature polyester film (PET film), the cable core thin film layer 8 is wrapped with a sheath layer 9 in an extruding mode, the sheath layer 9 is a low-smoke halogen-free flame-retardant polyolefin extrusion layer, and the sheath layer 9 is coated with a flame-retardant coating 10 and a water-blocking coating 11 outwards in sequence.

A flame-retardant coating 10 and a water-blocking coating 11 which are formed by coating on the sheath layer 9, wherein the flame-retardant coating 10 comprises the following material components: 8-12 wt% of fluororubber, 2-5 wt% of alumina micropowder, 2-4 wt% of rare earth oxide, 2-4 wt% of zirconia, 1-2 wt% of glycerol, 2-3 wt% of titanium dioxide, 2-4 wt% of lanthanum phosphate, 4-6 wt% of gadolinium zirconate and the balance of epoxy resin; the water-blocking coating 11 comprises the following material components: 20 to 25 weight percent of epoxy resin, 5 to 8 weight percent of tung oil, 3 to 5 weight percent of wool grease, 2 to 4 weight percent of rare earth oxide, 3 to 5 weight percent of chlorinated paraffin, 2 to 5 weight percent of zinc oxide, 2 to 5 weight percent of polyurethane and the balance of nitrile rubber.

As shown in fig. 2, the core conductor 1 of the insulated core is a copper wire with a diameter of 0.58 mm (millimeter), and the elongation of the conductor is controlled to be between 24% and 26.5%; the conductor insulation layer comprises a silica gel inner layer 2, a foam layer 3, a silica gel outer layer 4 and a core wire thin film layer 5. The silica gel inner layer 2 is positioned between the surface of the core wire conductor 1 and the foam layer 3, the thickness of the silica gel inner layer 2 is 4 micrometers (micrometers), the thickness of the foam layer 3 is 70 micrometers (micrometers), and the foam layer 3 is formed by using mixed high-density polyethylene as a material through chemical or physical foaming. The core thin film layer 5 located on the outermost surface of the conductor insulation layer is made of a high temperature polyester film (PET film) with a thickness of 5 μm, and the silica gel outer layer 4 formed by coating between the core thin film layer 5 and the foam layer 3 is 4 μm (micrometer). The inner silica gel layer 2 and the outer silica gel layer 4 are both formed by coating room temperature silicone rubber. The thickness of the silica gel inner layer 2 and the silica gel outer layer 4 is controlled between 3 μm and 5 μm, and the thickness of the core wire thin film layer 5 is controlled between 4 μm and 6 μm.

Claims (6)

1. A low dielectric constant communication cable comprises a cable core, wherein the cable core is composed of four pairs of line groups, and each pair of line groups is formed by mutually twisting two insulating core wires; have cable core shielding layer (7), its characterized in that on the cable core: each pair of line groups is wrapped with a pair of line shielding layers (6); the insulating core wire comprises a core wire conductor (1), and a silica gel inner layer (2), a foam layer (3), a silica gel outer layer (4) and a core wire thin film layer (5) are sequentially coated on the core wire conductor (1) from inside to outside; a cable core thin film layer (8), a sheath layer (9), a flame retardant coating (10) and a water blocking coating (11) are sequentially coated on the cable core shielding layer (7) from inside to outside; the thickness of the silica gel inner layer (2) and the silica gel outer layer (4) is 3-5 μm, and the thickness of the core wire thin film layer (5) is 4-6 μm.

2. The low dielectric constant communication cable of claim 1, wherein: the silica gel inner layer (2) and the silica gel outer layer (4) are formed by coating room-temperature silicone rubber.

3. The low dielectric constant communication cable of claim 1, wherein: the core wire film layer (5) and the cable core film layer (8) are high-temperature polyester film layers.

4. The low dielectric constant communication cable of claim 1, wherein: the pair of wire shielding layers (6) are copper-plastic composite shielding belts.

5. The low dielectric constant communication cable of claim 1, wherein: the cable core shielding layer (7) is a foil tape shielding layer or a woven shielding layer.

6. The low dielectric constant communication cable of claim 1, wherein: the sheath layer (9) is a low-smoke halogen-free flame-retardant polyolefin extrusion coating layer.

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