Warm Weather Tips for Solventless Resins
Solventless resins for dip and bake and VPI applications are pre-catalyzed.
In other words, unlike the trickle or roll-through resins which require
the addition of peroxide prior to use, these resins already have a pre-measured
amount of catalyst when shipped.
In order to cure these resins at 300-350°F in 1-2 hours and yet maintain
the tank stability a combination of right peroxide(s) and inhibitor(s)
are employed in the formulation.
With the solventless resins, the major cause of instability (increase
in viscosity and/or decrease in gel time) is heat. Resins in the tanks
maintained at around 70-75°F have much better stability than the resins
at 90-95ºF and higher. Since a majority of resin tanks do not have chillers,
hot dipping the units in combination with higher ambient temperatures
around this time of year can cause instability in the resin.
Just as gasoline producers have different blends for the winter and
summer months, the resin viscosity and gel time should be adjusted,
depending on the time of the year. In order to maintain tank stability
in summer months, the viscosity of the resin must be adjusted as close
to the lower end of the specification and gel time as close to the upper
end of the specification. In winter months, adjustments in the middle
of the specification is recommended. The key is proper maintenance.
Three critical parameters are temperature of the resin (in the tank
as well as the storage temperature), viscosity and gel time.
Dolph provides free evaluation of tank resin. A formal report, along
with recommendations for adjustments, if any, is furnished to the customer
in 2-3 days. Take advantage of it. Summer months are especially critical.
Impress upon every customer to send in the sample. With a well-maintained
resin in the tank, our customers will enjoy optimum performance of the
resin year after year.
