Hot weather and coating products – tip for use! 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.