PVC has made up the bulk of the global Wire and Cable polymers market for quite a while now, representing nearly 70% of the volume used in 2018. The list of PVC’s favorable attributes makes it clear why it has been the dominant player in materials for low voltage wire and cable insulation, bedding, and jacketing.
- Inherent flame retardancy
- Excellent physical properties (like resistance to corrosion, abrasion, and chemical attack)
- Easy processing due to it being a thermoplastic rather than thermoset polymer
- Very long service life (~25-40 years when used as insulation)
- Low cost
While PVC has plenty of advantages in Wire and Cable applications, there are some notable downsides that shouldn’t be overlooked.
- Difficult to recycle
- Halogen containing, failing to comply with the Wire and Cable Industry’s move toward Halogen-Free materials
- Off-gasing carcinogenic fumes when exposed to heat during processing and in service
- Poor fit for high voltage applications since it starts to dehydrochlorinate at temperatures as low as 100 °C
- High voltage cables need to handle continuous heat loads of 135 °C and higher
I think we can all agree that off-gasing carcinogenic fumes is a good enough reason to think twice before selecting PVC as a material for a wire and cable application. Is that the only reason Wire and Cable wants to phase out halogen-containing materials? In a manner of speaking yes, since those carcinogenic fumes are produced when recycling PVC, and using PVC in a medium to high voltage application exposes it to sufficient heat to initiate dehydrochlorination. To elaborate a little, Wire and Cable is moving away from halogen containing materials due to: