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Cable Jacketing
Similar to primary extrusion, cable jacketing is the process of applying an overall jacket to a cable consisting of multiple individual conductors. Kemcor?s jacket extrusion lines use closed loop vector computer controls to maintain precise diameter control. As with our primary extrusion process, SPC data is collected and used to automatically maintain close diameter tolerances.
Rarely do cabled wires remain unjacketed. In the majority of cases, a plastic jacket is extruded over the twisted components. Jackets cover and protect their enclosed wires against mechanical damage, chemical attack, and other harmful elements. A variety of thermoplastics are available as cable jackets. Among these are PVC, Polyethylene, TPE, polyurethane and nylon.
PVC jackets have a high resistance to ozone, acids, alcohols, oils, greases and gasoline. They are abrasion, moisture and fungus resistant and are typically used for indoor applications and general purpose installations. Kemcor's PVC jackets are flame resistant, lead free and comply with RoHS.
PVC's main disadvantage as a cable jacket is its stiffness at lower temperatures. They are not recommended for uses which require flexing at temperatures below -40° C.
Polyethylene is the most moisture resistant of the jacketing materials, and is used almost exclusively for direct burial cables. It is also commonly used for arial cables, although UV stabilizer pigments must be added to prevent degradation from sunlight. For electronic cables, polyethylene has two disadvantages - it supports combustion and significantly reduces cable flexibility.
TPE, or thermoplastic elastomer, has excellent electrical properties and low temperature flexibilities. Flame retardant varieties are available and are used on our UL listed tray cables. Flame retardant TPE is not currently RoHS compliant.
Polyurethanes have excellent abrasion resistance, high tear strength and exceptional resistance to oil, radiation, fungus, oxidation and ozone. They also exhibit outstanding memory properties, making it an ideal jacketing material for use in coiled cords. Compounds are available that are flame resistant, and have high gloss or low gloss.
Polyurethanes as a group have poor electrical properties and therefore are unsuitable as a primary insulation.
Nylon's most important characteristic is its toughness. It has excellent resistance to abrasion and a very low coefficient of friction. Its great hardness makes it ideal as a jacket over vinyl insulation in thin walled, shielded constructions. Even a thin coating - just a few mils - offers protection against shield strand penetration and prevents shorting of the conductors. It is resistant to oils, greases, dilute mineral acids, and most organic acids.
Its main disadvantages are its stiffness which reduces cable flexibility. Also, nylons as a group absorb moisture which degrade their mechanical and electrical properties. These changes are not permanent and its original properties are restored when the nylon dries out. For these reasons, nylons are not recommended as a primary insulation material, especially since nylon's electrical characteristics, while adequate, are not outstanding.
We invite you to contact us to discuss your requirements.
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