URETHANE
is ethyl carbamate, one of a group of organic compounds
sharing a common functional group with the general structure
(-NH(CO)O-).
Carbamates are esters of carbamic acid, NH2COOH,
an unstable compound. Since carbamic acid contains a nitrogen
attached to a carboxyl group, it is also an amide. Therefore,
carbamate esters may have alkyl or aryl groups substituted
on the nitrogen, or the amide function. Urethane
or ethyl carbamate, is unsubstituted, while ethyl N–methylcarbamate
has a methyl group attached to the nitrogen. Urethane should
not be confused with polyurethane which is not made from
carbamic acid at all. Urethane is available in many different
chemical formulae (due to
additives),
giving
it different chemical
properties,
and in varying thicknesses -- both of which affect its coefficient
of expansion. Urethanes can generally be classified
into four groups, thermoplastic
urethanes, urethane rubber, urethane as a coating and urethane
adhesives all of which have differing uses and physical properties.
Successful long term bonding of urethane to
itself, and to other substrates,
requires
careful
preparation
and
matching
of
the adhesive
being
used with the differing COEs of the substrates involved. BONDiTTM
products are among the few available that can be used
to bond urethanes to substrates with differing COE's for harsh
environments and long term deployment without debonding.
Our first recommended product for thermoplastic urethanes, urethane rubber
and urethane coatings is
to first apply an adhesion promoter or primer such as BONDiTTM A-43
or C-6, followed by one of the BONDiTTM B-4X series adhesives.
Our recommendation would change if unusually high chemical resistance is necessary
in which case we recommend our BONDiTTM A-3, in place
of the A-43 above.
Our other recommended product for urethane adhesives is simply using any of
the BONDiTTM B-4X
line products, unless high moisture resistance is required -- in which case
we recommend using an adhesive promoter BONDiTTM A-3
first.
Among the other substrates which urethanes can be bonded to using BONDiTTM products
are: UHMW, Delrin, fluoropolymers, polyethylene,
polyolefin, polypropylene, polyurethane, other urethanes, rubber, silicone,
thermoplastics, thermoset, ceramics, glass, fiberglass, wood, metals, stone,
aggregate
and
concrete.
To see our chart showing elongation rankings of the various
BONDiTTM products click
here. Call or email us for advice on
for COE ratings and matching BONDiTTM products for your application
at (707) 284-8808 or reltek@reltekllc.com.