fastening & assembly solutions and technology - Approved Business

Meeting the aesthetic
demands of the designer
Long bond lines, typically found between a deck and a hull of a yacht, can
experience extreme torsional loads
Industry today has many elements
where the colour of the
structural adhesive is paramount.
With so many products in
marine, vehicle manufacture and
construction being white, the
aesthetic demands of designers
and engineers require the adhe-
Adekit A236 has a short initial
hardening time of 4 hours
sive to be the same colour. This
was mainly due to improve or
reduce the clean-up process after
assembly but now a neat fillet
along the bond line is acceptable
and requisite. Whereas white or
clear single part mastics have
been common place for some
years to reduce movement
between panels and frames, the
emergence of a white structural
adhesive has been necessary for
structures requiring greater
integrity.
This causes the manufacturer
some logistic problems in the
production line. White epoxy
types are rare; they are rigid and
take a long time to cure before
handling is possible.
Methacrylates are too
quick and have unpleasant
odours which permeate
the work place. When
using methacrylates, it is
difficult to create a clean
edge as they enter the initial
polymerisation phase.
The continued demand to
bond dissimilar materials
together means that the
bond requires greater
elongation or flexibility
to cope with the different
coefficients of expansion
between the substrates
being used. In the previously
mentioned Industries, materials
bonded are usually aluminium to
GRP, or where long bond lines of
GRP are bonded to GRP, typically
between a deck and a hull
where extreme torsional loads
are experienced. The need for
high elongation prevents the use
of a stiff epoxy adhesive and
methacrylates are too fast to
allow assembly. Another advantage
that the PU structural 1:1
adhesive has over 5:1 methacrylate
adhesive is in its receptiveness
to primers and paints, by not
having a tacky like quality in the
immediate time after curing.
FAST OCTOBER 2011
FASTTOP TIPS
Aesthetic demands of the designer
often require the adhesive to be
white
The introduction of Adekit
A236 developed from the very
successful marine adhesive for
the bonding of composites
XP3550, combines the features
of a long open time of 40 mins
with a short initial hardening
time of 4 hrs. The adhesive is
available in 400ml cartridges or
in bulk for machine dispensing.
With a final cure overnight, the
product has a high gap fill greater
than 30mm and is white.
Lap shear strength on abraded
aluminium is 14 Mpa with an
impressive 60% elongation at
break, making the Adekit A236 a
prime candidate for applications
with high vibration, severe torsional
movement, long bead
lines, and where the
adhesive really does
need to be white.
AXSON 01638 660062
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