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Legacy planning for ‘perfect’ PVC-U
» » HOW SYSTEMS COMPANIES
manage legacy chemicals in recycled content
is key if they want to be able to guarantee
through-life performance.
To step into PVC-U recycling is something
of a step into the unknown. The lead
stabilisers and additives may be long since
gone from PVC-U extrusion but in recycled
material, they’re still very much there – or at
the very least could be. And that’s enough to
create a significant challenge.
PVC-U extrusion is a ‘dark art’. Profile
performance is dependent on the strict control
of its formulation and by definition,
recycled material is an unknown
quantity.
“If you don’t know the ratios of
the formulation you can’t possibly
predict how it’s going to perform
in extremes of temperature. The
differentiation between metal
salts or stabilisers can be really very
significant”, says Ian Cocken, Director
of Sales and Marketing, aluplast.
“If material was extruded in the 80s it’s
likely to have used barium cadmium, then
the industry switched to lead – you cannot
possibly know what you’re getting in recycled
content and you consequently can’t predict
product performance.”
The strategy adopted by the industry has
for the most part been to put this material
into standalone second-grade products, for
example reinforcements, to apply a skin of
‘virgin’ material or to foil product. The last two
options, however, appear fraught with risk.
“The substrate can have a significant impact
on surface gloss even and consistency of finish
and because it’s ‘unknown’ and variable, it
can be very difficult to control”, says Cocken.
“Even if you’re simply using it as a substrate
for a foil, you can still encounter challenges,
creating significant problems down the line.”
Processing approaching 200,000 tonnes of
PVC-U globally annually, equivalent to 75
per cent of the whole UK and Irish markets
combined and with its worldwide customer
base manufacturing more than 10million
windows per year, aluplast has the scale to
apply to product innovation.
Its solution to the challenge but also the
opportunities delivered by the introduction of
recycled PVC-U content into new generation
products, is simple in concept but draws on
52 » M AY 2018 » CL EARVI E W- UK . C O M
extrusion genius to
deliver it.
Available as an option
on its core Ideal 70 offer but
also contemporary new Ideal 4000 system,
ecotech, does this by isolating recycled
material only in the core web of its product
where dimensional stability is not critical.
The extrusion process applied by aluplast to
deliver this minor miracle in PVC-U profile
manufacture, uses pre and post-extrusion
product and post fabrication waste plus known
source post installation pelletized, PVC-U.
Two compound screw feeds then push
recycled and virgin material simultaneously
through the profile dye to create the profile
while maintaining a distinct separation between
the two. This separates and at the same time
locks recycled material away from areas of the
frame visible to the end-user or which perform
a structural role, which means that aluplast can
guarantee surface and finish quality.
“The development of ecotech has
represented a significant commitment in the
creation of special dyes and the increased
investment in running two extruders
simultaneously on a single profile but the
commercial advantages it delivers to our
customers makes that investment very much
worth it”, says Ian.
“aluplast surface profiles are completely flat
with depth of gloss and no pits, no extrusion
‘lines’ and that’s important for consumers.
PVC-U is seen as a ‘perfect’ product, there’s a
level of end-user expectation - imperfections
on the surface are immediately obvious.
“This also provides a stable substrate for the
millions of metres of foils we supply each year.
Critically, having doubled our foiling capacity
accompanied by investment in the latest CNC
foiling technologies, we are able to under-write
our foil offer with absolute confidence.”
aluplast for its part, foils approaching
1.5million metres of product each month.
This means that it holds thousands of metres
of coloured profiles in stock, including two
options for anthracite grey, which are available
as standard within just days of orders. It also
offers special foils in 15-days or less.
Ian adds, “The point is we’re not using
foils to disguise a sub-standard surface finish.
This means that we can offer exactly the same
guarantees of performance as on any extrusion
using virgin material only.
“This should offer comfort to those
installers who are currently getting call backs
on foils because of inherent flaws in process
and consequential surface stability in some
other systems.
“This aside ecotech offers a point of
differentiation and a very positive message
about the industry’s commitment to recycle
both of which deliver a key competitive
advantage.”