Methods to reduce the mixed viscosity
It is best to purchase products that are
formulated to yield the required viscosities to accommodate the processing. In
certain cases however, it may be desirable to lower the viscosity of a given
epoxy or polyurethane system to improve its handling characteristics. It must
be considered that all deviations from the recommended handling will result in
some form of trade-off.
The following are ways to reduce viscosities:
-
Warming the mixed material. Viscosities
decrease quickly with the application of heat. Two of the most significant
trade-offs will be shorter pot life and faster set up time.
-
Warming the resin only. This will lower
the resin viscosity and make mixing easier. The resultant trade-offs will be
the same as above, only to a lesser extent, since the hardener is cooler.
-
Warm the hardener only. This is the least
desirable since many hardeners contain at least some volatile components
and the volatility of these components will become more severe with the
application of heat. The same trade-offs will apply complicated by possible
cosmetic defects caused by the volatile ingredients.
Diluted resins are employed in some formulations
in order to increase filler loading and reduce costs. There are two types of
diluents that are commonly used for this purpose. Reactive diluents
which, as the name indicates, are part of the reaction during the curing process
and Non-reactive diluents which lower the viscosity but do not take part
in the actual reaction. Depending on the type of diluent employed, if any, may
cause surface defects as the resin is warmed to reduce the viscosity. It is
best to check with the supplier to ensure that there are no problems with
heating material components to reduce viscosity.
Make certain that there is good ventilation
present when heating any Epoxy or Polyurethane components and that any residual
fumes are drawn away from the operator. Observe all precautions on the
manufacturer's MSDS.
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Disclaimer: The above information is general in nature and is based solely on experiences by Crosslink Technology Inc. The recommendations provided herein may not be applicable in all situations. They are provided to the recipient as part of our customer service and the user must determine the relevance of the information to his/her application, considering any limitations that may be applicable thereto. Crosslink technology Inc. does not accept any liability for direct or consequential damages resulting from the implementations of these recommendations or the use of this information.
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