Cables
 Flexible Protection -
Phthalates in Wires and Cables
Plasticised polyvinyl chloride (PVC) is the most widely used
electrical insulation material in use today. Not only is it the
most commonly specified material for protecting wires in the many
thousands of different types of machines and appliances that we
have come to rely upon in our everyday lives, it is also the
preferred insulation for transmission cables and for the very
latest fibre optics.
About 25 per cent of all plasticised PVC is used by the wire,
cable and electrical industries.
Plasticised PVC is the preferred choice because it offers the
benefits of long service life and durability in a wide range of
conditions at exceptionally competitive prices.
Flexibility and Versatility
PVC's ability to bend and twist without cracking is a safety
feature which makes it particularly suitable for a wide range of
applications. This flexibility is provided by the addition of
plasticisers that are mixed with the PVC before it is extruded
around the metal wires it has to insulate and sheath.
By varying the phthalate used, cable manufacturers are able to
produce a wide range of sheathing for particular applications.
Manufacturers can select precisely the degree of flexibility
necessary to meet the mechanical requirements of the end
application. Road vehicles, for example, need very different wiring
to household appliances.
Furthermore, the equipment used by wire and cable producers -
although sophisticated - does not demand high levels of investment
helping to keep down the overall cost of the finished products.
Phthalates are widely used as general-purpose plasticisers
because they offer the advantage of lower costs and increased
production efficiency. This is achieved through improved melt
viscosity and production speeds of heated PVC with phthalates
added. Increased flow characteristics give better workability and
reduced out-of service breaks in equipment.
Phthalates are a family of substances which have a similar
molecular structure. Different individual phthalates, however,
confer particular qualities.
Phthalate plasticisers, in particular di-2-ethylhexyl phthalate
(DEHP or DOP), diisononyl phthalate (DINP) dipropylheptyl phthalate
(DPHP), and diisodecyl phthalate (DIDP), meet a wide range of
operating demands. This is vital, for example, for energy cables
used in buildings or for energy distribution wiring buried in the
ground which should remain flexible even at low temperatures.
Environment
In the past there have been concerns raised that phthalates may
leach out of end-of-life PVC cables in landfills. Whilst there
could be minimal leaching from PVC cables in landfill, phthalates
are readily biodegradable, as confirmed by the report of the
Swedish Environmental Protection Agency(1) and more
recently in the EU risk assessments of the most commonly used
phthalates.
(1) What needs to be done with PVC Waste Products? A report of
a Governmental Assignment, Swedish Environmental Protection Agency,
1996.
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