Coaxial cables foam-insulated

Typical HDPE—blow-molded products bottles, cans, trays, drums, tanks, and pails injection-molded products housewares, toys, food containers, cases, pails, and crates films, pipes, bags, conduit, wire and cable coating, foam, insulation for coaxial and communication cables... 

HDPE pipes are used for transporting water, sewer wastes, and gas they are also widely used in the chemical industry. Other significant applications include wire and cable coatings, foam, insulation for coaxial and communication cables, as well as those areas where high resistance to oil and chemicals is desirable. 

Cellular polyethylene is particularly useful in a number of electrical applications, such as in coaxial cables (CATV, military and other) and in twin leads. The foamed material is particularly useful in modem wire-coating equipment because of the ease of handling and the economies it provides in size and weight of insulated conductors (6). 

The main driver for fluoroplastic foams has been the insulation for data transmission cables. An example is coaxial cables that have relatively thick insulation. Its low dielectric constant and dissipation factor are desirable electrical properties. Air has the ideal dielectric constant (1.0). The ideal dissipation factor for data-cable insulation is zero. Perfluoropolymers have low dielectric constant and dissipation factor values (Table 11.2, see Ch. 6 for additional data). Foaming perfluorinated fluoropolymers further reduces the dielectric constants toward 1.0 and moves the dissipation factors closer to zero because the resin is replaced with air-filled cells in the insulation. The decrease in the dielectric constant is proportional for example, FEP insulation with 60% void content had a dielectric constant of More uniform foam cell size and smaller cells yield foams with the best electrical properties. 

In summary, conductors can be coated with a foamed insulation by a continuous wire process to produce coaxial cables. Even though only the production process for RG-62 was described, processing conditions can be altered to make other foam-insulated coaxial cables. 

EFFECTS OF PROCESSING CONDITIONS ON THE FOAMING PERFORMANCES IN THE POLYOLEFIN INSULATED COAXIAL CABLE EXTRUSION... 

A new low-loss cable was developed by improving the foaming degree of PE insulation. The foaming extrusion was performed in two extrusion lines. From the preliminary experiments in single extrusion line, optimizations of resin compositions and processing conditions on the foaming au value of the low-loss cable was produced in tandem extrusion line. The newly developed low-loss coaxial cable has 6 8% lower attenuation values compared to the conventional cable. 

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