Jacketing compounds

Ethylene vinyl acetate (EVA) polymers are used in thermoplastic and thermosetting jacketing compounds for apphcations that require flame retardancy combined with low smoke emission during the fire as well as the absence of halogen in the composition. 

Leyden and Rabb [68] have illustrated the rubber formula reconstruction process. Table 2.8 shows some of the difficulties encountered in the reconstruction of a complex wire and cable jacket compound. Forrest [38] has illustrated the reverse engineering of the reasonably complex highly flame retardant elastomer compound of... 

This material finds use as a sealing material in automotive applications and marine motor lead wire insulation. It has also been used as the base polymer for low flammability, halogen free, cable jacketing compounds. 

Automotive wire and cable jacketing compounds outdoor applications plastisols automotive interiors (except for crash pads) Wire and cable sealants plastisols calendering applications... 

L. Y. Lee, D. E. Roberts, B. L. Vest, K. TonyaU, Laser Printable Black Cable Jacketing Compounds, Proc. International Wire Cable Symp., 1995,823-828. 

The wire and cable industry has used fluoroproducts compounded with pigments and nucleants for decades. Semiconductive grades were introduced in the 1990s, but they tend to be limited to specialty applications like self-regulating heater cables described above. New areas of focus include jacket compounds for limited combustible cables and nanocomposites. 

Compounding can assist with the limited combustible requirements mentioned above. Although j ackets made with perfluoroplastic have been around since the advent of the plenum specifications, their market share has declined due to low productivity and relatively high cost. New products that combine compounding technology with the inherently low fuel load of perfluorinated polymers promise to open new windows for jacket compounds that possess the low flammability of perfluorinated resins combined with improved processibility. 

Poly(ethylene vinyl acetate) copolymers are commonly used in the wire and cable jacket compounds because of easy processing and good compatibility with many traditional flame retardants such as ATH and MDH. Recently, EVA also demonstrated their ability to promote nanocomposite formation by melt-blending with organoclays [38, 39]. 

Rigid and flexible PVC Polyolefins, polyamides and polyesters Plenum cable jacket compounds Paints and coatings Automotive components... 

The demand for white and coloured mbber articles for various applications is steadily growing. Rubbers are, depending on their content of olefinic double bonds, very sensitive to ozone, and hence effective antiozonants are necessary. Due to their discolouring and staining effect, para-phenylenediamine antiozonants cannot be used in compounds for white or coloured articles. A survey of the effectiveness of Vulkazon AFS, a cyclic acetal providing excellent ozone protection in coloured compounds based on various elastomers, is presented. The effectiveness of the cyclic acetal is compared with paraphenylenediamine antiozonants in chloroprene, butyl and halobutyl compounds. The effect in diene rubbers, where the cyclic acetal has to be used in combination with waxes, is investigated. Cyclic acetals do not affect the peroxide cure like other antiozonants and hence the material has also been tested in peroxide-cured cable jacket compounds based on a saturated elastomer. 2 refs. 

The primary use for Vamac in wire and cable is in ATH filled, flame resistant, nonhalogen jackets, usually peroxide cured (Table 6.32). The following typical jacket compounds are based on Vamac D and Vamac G. A color concentrate can be used in place of the carbon black. Armeen 18D and Vanfre VAM can be added to improve release properties but at the high filler levels associated with flame-retardant jacketing compounds, release is usually not a problem. 

Flame Retardant Non-Halogen Jacket Compounds Ingredients Parts... 

The fuel hose jacket compound is a HVA-2/Tetrone A cured compound for adhesion to the tie layer and fabric. It is a less expensive formulation as it does not have to meet the rigid dynamic properties of a power steering hose and is exposed to only occasional oil spills. 

Calcium carbonate provides a modest increase in volume resistivity in PVC, but very much less than calcined clay. One can expect 10-20 phr to approximately double volume resistivity at constant plasticizer level. Usually, however, loadings of calcium carbonate are accompanied by increases in plasticizer level. For a typical ester plasticizer, the decrease in volume resistivity fiom increased plasticizer offsets, or more than offsets, the decrease from adding filler. This can be avoided by using combinations of calcium carbonate with the minimum needed level of ester plasticizer, plus a secondary plasticizer having good electrical properties, such as chlorinated paraffin (Paroil , Dover Chemical) or polymerized aromatic oil (Kenflex A, Kenrich Petrochemical). These approaches are typically used in jacket compounds having insulation resistance specifications. Insulation compounds... 

Choice of plasticiser is of great importance. Most plasticisers are detrimental to the electrical properties of neoprene, but some ester plasticisers are particularly poor. These must be avoided even in jacket compounds if used without a barrier to prevent migration of plasticiser into the insulation. Naphthenic oils or hydrocarbon resins such as Kenflex A give the highest insulation values. A typical sheathing compound is shown in Table 7. 

EPDM rubber preferred for a great number of specific applications. For many years peroxide-cured EPDM based compounds have been applied, e.g., for window seals, automotive hoses, steam hoses, conveyer belts, roof sheeting, tank lining, roll coverings, mouldings, and last but not least, for electrical insulation and jacketing compounds. Two formulation types (403) are illustrated in Tables 33 and 34. 

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