PVC Nitrile

• Family: Elastomeric
• Use: Insulation and Sheathing 

General characteristics

NBR/PVC is a vulcanisable blend of Nitrile rubber and polyvinyl chloride. It is sometimes referred to as Nitrile/PVC. The proportion of Nitrile rubber and PVC can be varied within limits to give products having different degrees of resistance to oils and solvents.

Sheathings produced from NBR/PVC blends have excellent resistance to ozone and weathering. They exhibit good resistance to oils and aromatic solvents. They can be formulated to give good flame retardant, mechanical and abrasion-resistant properties. The resistance to heat ageing of NBR/PVC is good – of the same order as PCP but inferior to CSP. NBR/PVC has, however, rather poor low-temperature flexibility, although it is usually adequate for the outdoor temperatures encountered in this country.

Processing

Nitrile and PVC polymers are compounded in standard rubber compounding equipment and formulated to produce the relevant final properties. PVC/N requires vulcanisation. Extrusion is by single screw process, with vulcanisation achieved using standard CV tubes or by various autoclave processes. 

Uses of material/Cable types

NBR/PVC is used for sheathing purposes where resistance to oils and solvents is of paramount importance. Being, however, inferior in most other respects to CSP, it is only employed to a small degree for sheathing over heat-resisting elastomeric cores. The maximum continuous operating temperature for NBR/PVC is normally given as 70^oC. Some users claim temperatures up to 85^oC are possible, but this does not appear to have general recognition. 

Standards

Cables manufactured from PCP compounds are included in the following standards:

• IEC 60092 – series
• IEC 60245 – series
• BS EN 50363 – series
• BS EN 50525 – series
• BS 6708 
• BS 7655
• DIN VDE 0207 – series

List of Polymeric materials for cables used:

• Chlorinated Polyethylene – CPE
• Chloro Sulphonated Polyethylene – CSP
• Crossed Linked Polyethylene – XLPE
• Ethylene Propylene Rubber – EPR and EPDM
• Fire performance Silicone Rubber
• General Purpose Silicone Rubber
• LSZH Cross linked
• LSZH Thermoplastic
• Nylon
• Polyethylene
• Polyethylene – PE
• Polyvinyl Chloride – PVC Insulation
• Polyvinyl Chloride (PVC) Sheath
• PVC Nitrile