SEPTEMBER 2017 | 47
Products
Read online at www.proinstaller.co.uk
NEW TECHNOLOGY
SEALANT GOES FROM
STRENGTH TO STRENGTH
Breakthrough technologies are often
claimed, but Ceresit Fusion and Ceresit
7T are moving the goalposts for the way
sealants are produced and specified.
At the core of the technolo-
gy lies a curing system that
improves performance and
removes curing by-products
(oxime silicones) that have been
increasingly linked to carcinogenic
effects. Ceresit Fusion and Ceresit
7T, predominantly used in the
PVCu industry as perimeter seals
on PVCu, are oxime free and now
with a thicker body more amena-
ble to easier tooling and joint
finishing.
The products offer easy extru-
sion and good adhesion. Ceresit
Fusion is almost odourless during
application, fast curing and flexi-
ble (25 per cent movement). It has
excellent UV, weather and ageing
resistance, and can be used on
wood and aluminium, as well as
PVCu roofline.
From the roof to cellars, silicone
sealants are used in numerous ap-
plications by construction contrac-
tors and craftsmen everywhere.
There are different silicones for
different uses. However, not all of
them are believed to be entirely
harmless to health.
Impressive user safety
The oxime silicones based on
methyl ethyl ketoxime (MEKO) are
considered to be carcinogenic. But
now Ceresit Fusion’s oxime-free
technology offers impressive user
safety and an all-in-one solution
that covers virtually every applica-
tion, whether interior or exterior.
The silicone sealant product
group can be divided into three
systems: acetate silicones are char-
acterised by their acidic crosslink-
ing process, which means they re-
lease acetic acid upon curing and
give off a vinegary smell. Their
strengths lie primarily in sanitary
and kitchen applications.
However, they are unsuitable
for some substrates due to their
tendency to react with certain ma-
terials such as metal or concrete.
Another sort, alkoxy systems, un-
dergo neutral crosslinking and are
extensively odourless. They are
suitable for many substrates but
cure relatively slowly, which can
lead to sealant contamination.
an innovative solution that can
‘ completely
replace oximes ’
Neutrally crosslinking oxime
silicones based on methyl ethyl
ketoxime (MEKO), although offer-
ing good adhesion and fast curing,
release MEKO, the common
name for 2-butanone oxime. This
substance is suspected of being
carcinogenic and there is an occu-
pational exposure limit (OEL) on it
in countries such as Germany.
This means the wearing of
protective gloves and a protective
respiratory mask is additionally
required. The latter must also be
worn post application until con-
centrations safely fall. Depending
on the ventilation and the type
of room involved, this can take
several days.
Because of this situation,
Germany’s Industrial Association
for Sealants (IVD) has decided
to substitute out MEKO-releas-
ing products within the next two
years. It is also recommended that
the preventative measures de-
scribed also be applied in the case
of all other oxime silicones, as the
suspicion of carcinogenic effects
cannot be precluded.
True all-rounder
Following extensive research,
Ceresit Fusion and Ceresit 7T
provide an innovative solution that
can completely replace oximes
while uniting all the advantages
of a neutrally crosslinking sealant.
This new silicone generation is
able to ensure outstanding adhe-
sion on virtually all substrates,
whether concrete, glass, metal,
wood or tiles.
Compliant with EN 15651,
the products are also suitable
for glazing systems and sanitary
applications. The flexible material
exhibits very good compatibility
on most standard commercial
coating systems. It has a shelf life
of 18 months and is certified for
use in both clean rooms and HVAC
systems.
A true all-rounder, it is easy to
use and fast curing with minimal
shrinkage.
Compared to oxime silicones,
the product does not give rise to
critical emissions – making it ideal
for interior applications without
restriction. The formulation is also
suitable for external applications
due to its UV stability and high
weather resistance.