Ethylene-propylene rubbers cables

R. B. Blodgett, "Ethylene—Propylene Rubber and Crosslinked Polyethylene as Insulations for 90°C Rated Medium Voltage Cables," Rubber Chem. Technol, 52, 410-424 (1978). 

NEMA WC8/1998 Ethylene propylene rubber insulated wire and cable for the transmission and distribution of power ... 

The main use of ethylene-propylene rubber is to produce automotive parts such as gaskets, mechanical goods, wire, and cable coating. It may also be used to produce tires. 

D 2770 Ozone-Resist Ethylene-Propylene Rubber Integral Insulation Jacket for Wire Cable. 

D 2802 Ozone-Resistant Ethylene-Propylene Rubber Insulation for Wire Cable. 

PVC, another widely used polymer for wire and cable insulation, crosslinks under irradiation in an inert atmosphere. When irradiated in air, scission predominates.To make cross-linking dominant, multifunctional monomers, such as trifunctional acrylates and methacrylates, must be added. Fluoropolymers, such as copol5miers of ethylene and tetrafluoroethylene (ETFE), or polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF), are widely used in wire and cable insulations. They are relatively easy to process and have excellent chemical and thermal resistance, but tend to creep, crack, and possess low mechanical stress at temperatures near their melting points. Radiation has been found to improve their mechanical properties and crack resistance. Ethylene propylene rubber (EPR) has also been used for wire and cable insulation. When blended with thermoplastic polyefins, such as low density polyethylene (LDPE), its processibility improves significantly. The typical addition of LDPE is 10%. Ethylene propylene copolymers and terpolymers with high PE content can be cross-linked by irradiation. ... 

Depending upon the end-use requirement, wire jacketing is most often made from formulated polyethylene. Blends of polyethylene and ethylene-propylene rubber are used if greafer flexibilify is needed, especially as fhe diameter of fhe jacketing increases as for cables. Another possibility is EPDM rubber with... 

Ethylene propylene rubber (EPR) has been also used for wire and cable insulation. When blended with thermoplastic polyefins such as LDPE its processibility improves significantly. The typical addition of LDPE is 10%. Ethylene propylene copolymers and terpolymers with high PE content can be cross-linked by irradiation.34... 

A number of manufactured products comprising thermoplastics (polyethylene, polyvinylchloride, polyamides,. ..) or elastomers (natural rubber, nitrile rubber, ethylene propylene rubber, silicones) are processed by cross-linking to improve their performances in insulated electric wires and cables, multilayered films for cooking pouches, shape memory tubes, pressure resistant water pipes, expandable foams, automotive parts exposed to motor... 

In power transmission and distribution cables rated 5 kv and above low density polyethylene (PE), cross-linked low density polyethylene (XLPE) and ethylene-propylene rubbers (EPR) are used in large quantities. 

The thermoset elastomers most frequently used for cables are ethylene propylene rubber and cross-linked polyethylene. 

BS6622 Specification for cables with extruded cross-linked polyethylene or ethylene propylene rubber insulation for rated voltages from 3.8/6.6 kV up to 19/33 kV. 

Ethylene-propylene rubber has relatively high resistance to heat. Standard formulations can be used continuously at temperatures of 250-300°F (121-148°C) in air. hr the absence of air, such as in a steam hose lining or cable insulation covered with an outer jacket, higher temperatures can be tolerated. It is also possible by special compounding to produce material that can be used in services up to 350°F (176°C). Standard compoimds can be used in intermittent service at 350°F (176°C). 

Ethylene-propylene rubber finds application in the electrical industry and in the manufacture of electrical equipment. One of the primary applications is as an insulating material. It is used for medium-voltage (up to 35 kV) and secondary network power cable, coverings for line and multiplex distribution wire, jacketing and insulation for types S and SJ flexible cords, and insulation for automotive ignition cable. 

Matty polymers may be used for produetion of wire and cable. These include polyethylene, crosslinked polyethylene, chlorosnlfonated polyethylene, ethylene-propylene rubber, polyvinylchloride, bntyl robber, styrene bntadiene rubber, silicone rubber, natural robber, polyisoprene robber, polyurethane, nitrile butadiene rubber, polychloroprene, polysulfone, thermoplastie elastomers, polyimide, and polyamides. Selection of polymer(s) depends on projected conditions of service such as temperature, presence of corrosive liquids, surrounding temperature, quality of insulation, etc. 

Uses of Ethylene-Propylene Rubbers. EPDM and EPR vulcanizates are used in extruded profiles, cable insulation and jacketing, and roofing membranes. There are many automotive uses radiator hose, door and trunk seals, insulation, jacketing, and others. These elastomers are also used in applications such as window and architectural profiles, dock fenders, and washing-machine hoses. In short, their applications are extensive and diverse. Ethylene-propylene rubbers may be the most versatile of general-purpose rubbers. In addition, EP rubbers are added to polyolefin plastics as impact modifiers and as components of certain thermoplastic elastomer compositions (e.g., thermoplastic vulcanizates, which are discussed later in this chapter). 

Which of these two principal types is the better is not clear-cut. The plastics insulation is relatively easy to apply by cross-head extrusion. PVC, polyethylene, crosslinked polyethylene, ethylene propylene rubbers are commonly used. This is a relatively cheap and efficient process. Paper cable manufacture, by comparison, is a complex and labour-intensive... 

Ozone-Resistant Ethylene-Propylene Rubber Insulation for Wire and Cable, Spec, for, (D 2802) 33... 

The cross-linking of materials such as polyethylene, ethylene propylene rubber and some other rubbers used for cable insulation and sheathing is conventionally measured for quality purposes by means of a test of elongation imder a specified load at elevated temperature of the permanent set measured when the load is removed and the sample allowed to cool. This hot-set test is very good when it is possible to cut appropriately sized tensile test dumb-bells for the measurement. Where samples are irregular and small, as may be the case in work of a more investigative nature, it is much more difficult to apply, and TMA has been applied, albeit in a fairly qualitative way, to the problem of finding out if a specimen is cross-linked. 

They are finding extensive use in the car industry, for example, for car bumpers and radiator grills. They are also of interest for such diverse applications as cable sheathing and ski boots. There is reason to believe that blends of polypropylene with ethylene-propylene rubbers have considerable scope for further development. Whilst it provides the polymer manufacturers with an opportunity to use up spare capacity for making both polypropylene and the ethylene-propylene rubbers the rubber product manufacturers are less likely to gain much from their existence. This is because most of the processing being carried out with these materials is done by thermoplastics converters rather than the rubber industry. 

Cable and wire -EPDM m [ELASTOMERS, SYNTHETIC - ETHYLENE-PROPYLENE-DIENE RUBBER] (Vol 8)... 

EPDM Rubber Sulfur-vulcanizable thermosetting elastomer produced from ethylene, propylene, and a small amount of nonconjugated diene such as hexadiene. Has good weatherability and chemical and heat resistance. Used as impact modifiers and for weather stripping, auto parts, cable insulation, conveyor belts, hoses, and tubing. Also called EPDM. 

---