All the laminates that we supply
can be glued satisfactorily using high performance
adhesives of either hot melt or water based
PVA/EVA type. Some laminates are easier to
glue than others and this, together with
other factors such as the nature of both
the surfaces to be joined, the type of gluing
machine and adhesive application system etc,
will affect the choice of adhesive.
A U.V.
varnish must be specially formulated to
allow adhesives to bond to its surface and
we therefore need to know if a job requires
a glueable varnish finish. Glueable varnishes
again require high performance adhesives
chosen
to perform correctly in the given circumstances. Recommendations
If you are at all unused
to gluing laminates or varnishes we strongly
recommend that you
discuss your requirements with your adhesive
supplier. We will be glad to supply material
for laboratory or machine proofing if needed.
We
suggest that glue flaps be perforated to
allow some physical penetration of adhesive
through the laminate or varnish into
the base
board. This will improve both the setting
speed and the final strength of the bond.
Do
not print in the glue flap or have any
sealer coatings in this area. This
is crucially
important
when gluing a U.V. varnished job because
the adhesion of the varnish to underlying
ink is
usually the weakest part of the joint
and failure is likely at this point.
The bond
of varnish
to board is much stronger than that
of varnish to ink.
Do not try to use water-based
adhesives to join two laminated or varnished
surfaces together since neither can
absorb the
water from the
adhesive. An extremely slow setting
speed and a poor final bond will
result. If
you need
to make such a joint, use either
hot melt adhesive or a double sided, self
adhesive
tape.
Some joints, such as the crash
lock bases of whisky cartons, are difficult
to make
and have
to have high strength over a long
time period. We would not recommend
any
of our finishes,
except Spot U.V. varnish, as being
suitable for use in such circumstances.
With the
spot UV process the glue flaps
can be left free
from varnish.
If a mistake has been
made and gluing is problematical, it is
possible
to fit an
attachment to most
gluing machines that will mill
or grind the laminate or varnish
off
the glue
flap and
thus allow normal processing. |
